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Toxoplasma gondii in lactating animals: potential risk to milk consuming population in Khyber Pakhtunkhwa

Toxoplasma gondii em animais lactantes: risco potencial para população consumidora de leite em Khyber Pakhtunkhwa

Abstract

Toxoplasma gondii is an intracellular zoonotic protozoan parasite usually infects human and animal worldwide. This study aimed to analyze the sero-prevalence of T. gondii in blood of lactating animals and human living in close proximity and also to detect Toxoplasma DNA in unpasteurized milk of the studied animals. A total of 233 blood and milk samples were collected from lactating animals, and 735 blood samples were taken from humans in District Upper Dir, Khyber Pakhtunkhwa, Pakistan. The blood samples were analyzed through ELISA while the milk samples were analyzed by PCR for the presence of T. gondii DNA. A standard questionnaire was introduced to collect the data from the participants. In animals, the reported sero-prevalence was 32.18% for IgM, 17.16% for IgG, and 6.4% for both IgM and IgG. The reported positivity for T. gondii DNA in milk was 14.44%, 34.8%, 20%, and 26% in sheep, goats, cows, and buffaloes, respectively. In the human blood samples, 9.8% were found positive for IgM and 11.2% for IgG while none of the samples was found positive for both IgM and IgG. Overall sero-prevalence reported in females was significantly higher than the male (p<0.05) poor hygiene condition (p < 0.0001) were the significant risk factors associated with T. gondii infections in animals. In conclusion, T. gondii infection is prevalent in lactating animals and humans using their raw milk in the study area. It is suggested that raw milk should be considered as a vehicle for the transmission of T. gondii to humans. Proper pasteurization of milk is very useful in limiting the transmission of infection. Awareness and control programs should be implemented to prevent the infection.

Keywords
Toxoplasma gondii; sheep; goat; cow; buffalo; milk; ELISA; PCR

Resumo

Toxoplasma gondii é um protozoário parasita intracelular zoonótico que geralmente infecta humanos e animais em todo o mundo. Este estudo teve como objetivo analisar a soroprevalência de T. gondii no sangue de animais lactantes e humanos que vivem em proximidade, além de detectar o DNA de Toxoplasma no leite não pasteurizado dos indivíduos estudados. Um total de 233 amostras de sangue e leite foram coletadas de animais lactantes e 735 amostras de sangue foram coletadas de humanos no Distrito Upper Dir Khyber Pakhtunkhwa, no Paquistão. As amostras de sangue foram analisadas pelo método ELISA enquanto as amostras de leite foram analisadas por PCR para a presença de DNA de T. gondii. Um questionário padrão foi introduzido para coletar os dados dos participantes. Em animais, a soroprevalência relatada foi de 32,18% para IgM, 17,16% para IgG e 6,4% para IgM e IgG. A positividade relatada para DNA de T. gondii encontrada no leite foi de 14,44%, 34,8%, 20% e 26% em ovelhas, cabras, vacas e búfalas, respectivamente. Nas amostras de sangue humano, 9,8% foram consideradas positivas para IgM e 11,2% para IgG, enquanto nenhuma das amostras foi considerada positiva para IgM e IgG. A soroprevalência geral relatada em mulheres foi significativamente maior do que em homens (p < 0,05). Neste estudo, contato com gatos (p < 0,0001), hábitos alimentares (p < 0,0001), fonte de água para beber (p < 0,0001) e más condições de higiene (p < 0,0001) foram os fatores de risco significativos associados a infecções por T. gondii em animais. Em conclusão, a infecção por T. gondii é prevalecente em animais lactantes e humanos que utilizam leite cru, isto é, não-pasteurizado, na área de estudo. Sugere-se que o leite não-pasteurizado seja considerado um veículo de transmissão do T. gondii para humanos. A pasteurização adequada do leite é muito útil para limitar a transmissão de infecções. Programas de conscientização e controle devem ser implementados para prevenir a infecção.

Palavras-chave:
Toxoplasma gondii; ovelha; cabra; vaca; búfala; leite; ELISA; PCR

1. Introduction

Toxoplasma gondii (T. gondii) is an obligate intracellular cyst forming apicomplexan parasite, infecting all warm-blooded animals including humans, with a cosmopolitan distribution (Rouatbi et al., 2019ROUATBI, M., AMAIRIA, S., AMDOUNI, Y., BOUSSAADOUN, M.A., AYADI, O., AL-HOSARY, A.A.T., REKIK, M., BEN ABDALLAH, R., AOUN, K., DARGHOUTH, M.A., WIELAND, B. and GHARBI, M., 2019. Toxoplasma gondii infection and toxoplasmosis in North Africa: a review. Parasite (Paris, France), vol. 26, pp. 6. http://dx.doi.org/10.1051/parasite/2019006. PMid:30767889.
http://dx.doi.org/10.1051/parasite/20190...
; Sharif et al., 2009SHARIF, M., DARYANI, A., NASROLAHEI, M. and ZIAPOUR, S.P., 2009. Prevalence of Toxoplasma gondii antibodies in stray cats in Sari, northern Iran. Tropical Animal Health and Production, vol. 41, no. 2, pp. 183-187. http://dx.doi.org/10.1007/s11250-008-9173-y. PMid:18473184.
http://dx.doi.org/10.1007/s11250-008-917...
) and is a causative agent of the geographically omnipresent infection known as toxoplasmosis (Rahimi et al., 2015RAHIMI, M.T., DARYANI, A., SARVI, S., SHOKRI, A., AHMADPOUR, E., TESHNIZI, S.H., MIZANI, A. and SHARIF, M., 2015. Cats and Toxoplasma gondii: a systematic review and meta-analysis in Iran. The Onderstepoort Journal of Veterinary Research, vol. 82, no. 1, pp. e1-e10. http://dx.doi.org/10.4102/ojvr.v82i1.823. PMid:26017063.
http://dx.doi.org/10.4102/ojvr.v82i1.823...
; Sugden et al., 2016SUGDEN, K., MOFFITT, T.E., PINTO, L., POULTON, R., WILLIAMS, B.S. and CASPI, A., 2016. Is Toxoplasma Gondii Infection Related to Brain and Behavior Impairments in Humans? Evidence from a PopulationRepresentative Birth Cohort. PLoS One, vol. 11, no. 2, pp. e0148435. http://dx.doi.org/10.1371/journal.pone.0148435. PMid:26886853.
http://dx.doi.org/10.1371/journal.pone.0...
). The lactating animals are the significant hosts of T. gondii and thus considered most important transmission route of T. gondii infection. Usually, T. gondii infection is passed to grazing animals when coming in contact with the soil contaminated with T. gondii oocysts. Then these infected animals transmit tachyzoites through unpasteurized milk to their offspring as well as to human beings (Khamsian et al., 2021KHAMSIAN, E.M., HAJIMOHAMMADI, B., ESLAMI, G., FALLAHZADEH, M.H. and HOSSEINI, S.S., 2021. Toxoplasma gondii in milk of human and goat from the desert area in Central Iran. Iranian Journal of Parasitology, vol. 16, no. 4, pp. 601-609. http://dx.doi.org/10.18502/ijpa.v16i4.7873. PMid:35082889.
http://dx.doi.org/10.18502/ijpa.v16i4.78...
; Camossi et al., 2011CAMOSSI, L.G., GRECA-JÚNIOR, H., CORRÊA, A.P.F.L., RICHINI-PEREIRA, V.B., SILVA, R.C., DA SILVA, A.V. and LANGONI, H., 2011. Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes. Veterinary Parasitology, vol. 177, no. 3-4, pp. 256-261. http://dx.doi.org/10.1016/j.vetpar.2010.12.007. PMid:21216534.
http://dx.doi.org/10.1016/j.vetpar.2010....
; Sharif et al., 2009SHARIF, M., DARYANI, A., NASROLAHEI, M. and ZIAPOUR, S.P., 2009. Prevalence of Toxoplasma gondii antibodies in stray cats in Sari, northern Iran. Tropical Animal Health and Production, vol. 41, no. 2, pp. 183-187. http://dx.doi.org/10.1007/s11250-008-9173-y. PMid:18473184.
http://dx.doi.org/10.1007/s11250-008-917...
).

The disease is noticeable in both medical as well as veterinary field, as it result a significantly serious drain on productivity and the economy by damaging animal husbandry due to stillbirths and neonatal mortality in animals and stress on the health systems (Rahimi et al., 2015RAHIMI, M.T., DARYANI, A., SARVI, S., SHOKRI, A., AHMADPOUR, E., TESHNIZI, S.H., MIZANI, A. and SHARIF, M., 2015. Cats and Toxoplasma gondii: a systematic review and meta-analysis in Iran. The Onderstepoort Journal of Veterinary Research, vol. 82, no. 1, pp. e1-e10. http://dx.doi.org/10.4102/ojvr.v82i1.823. PMid:26017063.
http://dx.doi.org/10.4102/ojvr.v82i1.823...
, Sharif et al., 2009SHARIF, M., DARYANI, A., NASROLAHEI, M. and ZIAPOUR, S.P., 2009. Prevalence of Toxoplasma gondii antibodies in stray cats in Sari, northern Iran. Tropical Animal Health and Production, vol. 41, no. 2, pp. 183-187. http://dx.doi.org/10.1007/s11250-008-9173-y. PMid:18473184.
http://dx.doi.org/10.1007/s11250-008-917...
). Many epidemics responsible for high mortality and morbidity and were reported in livestock sector of Pakistan (Ahmed et al., 2016AHMED, H., MALIK, A., ARSHAD, M., MUSTAFA, I., KHAN, M.R., AFZAL, M.S., ALI, S., MOBEEN, M. and SIMSEK, S., 2016. Seroprevalence and spatial distribution of toxoplasmosis in sheep and goats in North-Eastern Region of Pakistan. Korean Journal of Parasitology, vol. 54, no. 4, pp. 439-446. http://dx.doi.org/10.3347/kjp.2016.54.4.439. PMid:27658595.
http://dx.doi.org/10.3347/kjp.2016.54.4....
). Toxoplasma infection in dairy animals may illustrate a real risk for transmission of parasite to human (Van den Brom et al., 2020VAN DEN BROM, R., DE JONG, A., VAN ENGELEN, E., HEUVELINK, A. and VELLEMA, P., 2020. Zoonotic risks of pathogens from sheep and their milk borne transmission. Small Ruminant Research, vol. 189, pp. 106123. http://dx.doi.org/10.1016/j.smallrumres.2020.106123. PMid:32427176.
http://dx.doi.org/10.1016/j.smallrumres....
; Omonijo et al., 2022OMONIJO, A.O., KALINDA, C. and MUKARATIRWA, S., 2022. Toxoplasma gondii Infections in Animals and humans in southern africa: a systematic review and meta-analysis. Pathogens (Basel, Switzerland), vol. 11, no. 2, pp. 183. http://dx.doi.org/10.3390/pathogens11020183. PMid:35215126.
http://dx.doi.org/10.3390/pathogens11020...
), causes different complications such as Toxoplasmic encephalitis, blindness, stillbirth, abortion, fetal abnormalities, or even prenatal death in congenital cases, pneumonia, and sometimes heart infection (Chan and Smith, 2018CHAN, M.Y. and SMITH, M.A., 2018. Infections in pregnancy. In C.A. MCQUEEN, ed. Comprehensive toxicology. USA: Elsevier, pp. 232-249. http://dx.doi.org/10.1016/B978-0-12-801238-3.64293-9.
http://dx.doi.org/10.1016/B978-0-12-8012...
). Globally prevalence of T. gondii is variable, different countries ranging from zero to hundred percent prevalence rates depending upon their civilizations, societies, inhabitant’s life styles, animal’s age and climate conditions (Lashari et al., 2018LASHARI, M.H., AFZAL, F., and FAROOQ, U., 2018. Hematological changes in free-range chicken (Gallus domesticus) naturally infected with Toxoplasma gondii. Sarhad Journal of Agriculture, vol. 34, no. 4, 973-978. http://dx.doi.org/10.17582/journal.sja/2018/34.4.973.978.
http://dx.doi.org/10.17582/journal.sja/2...
; Thai et al., 2019THÁI, T.L., JUN, H., PARK, S.H., LÊ, H.G., LEE, J., AHN, S.K., KANG, J.M., MYINT, M.K., LIN, K., SOHN, W.M., NAM, H.W., NA, B.K. and KIM, T.S.. 2019. Seroprevalence of Toxoplasma gondii among School Children in Pyin Oo Lwin and Naung Cho, Upper Myanmar. Korean Journal of Parasitology, vol. 57, no. 3, pp. 303-308. http://dx.doi.org/10.3347/kjp.2019.57.3.303. PMid:31284355.
http://dx.doi.org/10.3347/kjp.2019.57.3....
). The broad dissemination of this parasite may be attributed to various factors such as its co-evolution with multiple hosts (Mukhopadhyay et al., 2020MUKHOPADHYAY, D., ARRANZ-SOLÍS, D. and SAEIJ, J.P., 2020. Influence of the host and parasite strain on the immune response during Toxoplasma infection. Frontiers in Cellular and Infection Microbiology, vol. 10, pp. 580425. http://dx.doi.org/10.3389/fcimb.2020.580425. PMid:33178630.
http://dx.doi.org/10.3389/fcimb.2020.580...
; Alzaheb, 2018ALZAHEB, R.A., 2018. Seroprevalence of Toxoplasma gondii and its associated risk factors among women of reproductive age in Saudi Arabia: a systematic review and meta-analysis. International Journal of Women’s Health, vol. 10, pp. 537-544. http://dx.doi.org/10.2147/IJWH.S173640. PMid:30288126.
http://dx.doi.org/10.2147/IJWH.S173640...
; Ding et al., 2017DING, H., GAO, Y.M., DENG, Y., LAMBERTON, P.H. and LU, D.B., 2017. A systematic review and meta-analysis of the seroprevalence of Toxoplasma gondii in cats in mainland China. Parasites & Vectors, vol. 10, no. 1, pp. 27. http://dx.doi.org/10.1186/s13071-017-1970-6. PMid:28086987.
http://dx.doi.org/10.1186/s13071-017-197...
; Sanchez and Besteiro, 2021SANCHEZ, S.G. and BESTEIRO, S., 2021. The pathogenicity and virulence of Toxoplasma gondii. Virulence, vol. 12, no. 1, pp. 3095-3114. http://dx.doi.org/10.1080/21505594.2021.2012346. PMid:34895084.
http://dx.doi.org/10.1080/21505594.2021....
), multiple transmission routes (Foroutan et al., 2018FOROUTAN, M., DALVAND, S., DARYANI, A., AHMADPOUR, E., MAJIDIANI, H., KHADEMVATAN, S. and ABBASI, E., 2018. Rolling up the pieces of a puzzle: a systematic review and meta-analysis of the prevalence of toxoplasmosis in Iran. Alexandria Journal of Medicine, vol. 54, no. 3, pp. 189-196. http://dx.doi.org/10.1016/j.ajme.2017.06.003.
http://dx.doi.org/10.1016/j.ajme.2017.06...
), presence of diverse T. gondii genotypes (Shapiro et al., 2019SHAPIRO, K., BAHIA-OLIVEIRA, L., DIXON, B., DUMÈTRE, A., DE WIT, L.A., VANWORMER, E. and VILLENA, I., 2019. Environmental transmission of Toxoplasma gondii: oocysts in water, soil and food. Food and Waterborne Parasitology, vol. 15, pp. e00049. http://dx.doi.org/10.1016/j.fawpar.2019.e00049. PMid:32095620.
http://dx.doi.org/10.1016/j.fawpar.2019....
), long viability in the moderate environment (Galvan-Ramirez et al., 2012GALVAN-RAMIREZ, M.L., TROYO, R., ROMAN, S., CALVILLO-SANCHEZ, C. and BERNAL-REDONDO, R., 2012. A systematic review and meta-analysis of Toxoplasma gondii infection among the Mexican population. Parasites & Vectors, vol. 5, pp. 271. http://dx.doi.org/10.1186/1756-3305-5-271. PMid:23181616.
http://dx.doi.org/10.1186/1756-3305-5-27...
), longer infectious time for about 18 months (Furtado et al., 2011FURTADO, J.M., SMITH, J.R., BELFORT JUNIOR, R., GATTEY, D. and WINTHROP, K.L., 2011. Toxoplasmosis: a global threat. Journal of Global Infectious Diseases, vol. 3, no. 3, pp. 281-284. http://dx.doi.org/10.4103/0974-777X.83536. PMid:21887062.
http://dx.doi.org/10.4103/0974-777X.8353...
) and resistant to freezing, drying and even disinfection (Rahimi et al., 2015RAHIMI, M.T., DARYANI, A., SARVI, S., SHOKRI, A., AHMADPOUR, E., TESHNIZI, S.H., MIZANI, A. and SHARIF, M., 2015. Cats and Toxoplasma gondii: a systematic review and meta-analysis in Iran. The Onderstepoort Journal of Veterinary Research, vol. 82, no. 1, pp. e1-e10. http://dx.doi.org/10.4102/ojvr.v82i1.823. PMid:26017063.
http://dx.doi.org/10.4102/ojvr.v82i1.823...
). Milk is a highly consumable complete source of food as it contains all required nutrients in good proportion. Peoples need hygienic quality of milk for daily use and they fulfill their need from domestic and farm animals. The milk of these animals represents a source of infection for humans, therefore required to monitor prevalence of infection, aimed to reduce infections in them as much as possible. Better information regarding the environmental contamination of T. gondii is critical and vital to holistic determinations of potential health risks (Aguirre et al., 2019AGUIRRE, A.A., LONGCORE, T., BARBIERI, M., DABRITZ, H., HILL, D., KLEIN, P.N., LEPCZYK, C., LILLY, E.L., MCLEOD, R., MILCARSKY, J., MURPHY, C.E., SU, C., VANWORMER, E., YOLKEN, R. and SIZEMORE, G.C., 2019. The one health approach to toxoplasmosis: epidemiology, control, and prevention strategies. EcoHealth, vol. 16, no. 2, pp. 378-390. http://dx.doi.org/10.1007/s10393-019-01405-7. PMid:30945159.
http://dx.doi.org/10.1007/s10393-019-014...
) and highlights the areas for further investigation so to implement effective measures to prevent T. gondii infections (Stelzer et al., 2019STELZER, S., BASSO, W., SILVÁN, J.B., ORTEGA-MORA, L.M., MAKSIMOV, P., GETHMANN, J., CONRATHS, F.J., and SCHARES, G., 2019. Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact. Food and Waterborne Parasitology, vol. 15, e00037. https://doi.org/10.1016/j.fawpar.2019.e00037.
https://doi.org/10.1016/j.fawpar.2019.e0...
). Due to the economic importance of toxoplasmosis, this study aimed to analyze the sero-prevalence of T. gondii in blood of lactating animals and human living in close proximity and also to detect Toxoplasma DNA in unpasteurized milk of the studied animals in District Upper Dir, Pakistan.

2. Materials and Methods

2.1. Description of the study area

The study was conducted in Upper Dir District of Khyber Pakhtunkhwa, Pakistan, lies at latitude of 35° 9’55.89” N and 72° 2’48.54” E longitude having total areas of the district is 3,699 km2 (Figure 1). People of the area mostly depend on domestic animals for the purpose of milk and different types of dairy products such as butter, cheese, yoghurt, and meat. These are the main sources of income for the people of the region. Basic educational and health facilities have also been provided by the Government to the people of the area.

Figure 1
Map of Pakistan. The red area represents Upper Dir, Khyber Pakhtunkhwa (Ruhoollah et al., 2021RUHOOLLAH, KHAN, W., AL-JABR, O.A., KHAN, T., KHAN, A., EL-GHAREEB, W.R., AGUILAR-MARCELINO, L., HUSSEIN, E.O.S., ALHIMAIDI, A.R. and SWELUM, A.A., 2021. Prevalence of gastrointestinal parasite in small ruminants of District Dir Upper Khyber Pakhtunkhwa Province of Pakistan. Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 83, pp. e248978. https://doi.org/10.1590/1519-6984.248978.
https://doi.org/10.1590/1519-6984.248978...
).

2.2. Ethical considerations

The Advance Study Research Board (ASRB), University of Peshawar Khyber Pakhtunkhwa, Pakistan has approved the research Proposal. Special permission was obtained from the owner of the animals during sampling. Informed consent was obtained from all participants of the study.

2.3. Data collection

Data related risk factors of toxoxoplasma in animals (feeding habits, type of food, source of drinking water, hygienic conditions and age) and humans (age, contact with cats and gender) were collected through a predesigned questionnaire.

2.4. Collection of samples

2.4.1. Collection of blood and milk samples from animal

Blood and milk samples were collected from 233 lactating animals including sheep (n=76), goats (n=69), cows (n=50) and buffaloes (n=38)], from five different tehsils (Proper Dir, Wari, Barawal, Shringal and Kalkot) in district Upper Dir Khyber Pakhtunkhswa Pakistan. Blood samples (5mL) were collected from the jugular vein of lactating animals. Milk samples (5mL) were taken manually after disinfection of the teats with 70% ethanol. All the blood and milk samples were immediately transported to the Laboratory of Virology and Immunology, Department of Zoology, University of Peshawar. Serum was separated by centrifugation. All samples were stored at -20°C for serological and molecular assays.

2.4.2. Collection of blood samples from humans

A total of 735 blood samples (350 males and 385 females) were collected from the participants who live nearby the animals and consume their milk especially animal’s owners and their family members.

All the blood samples were collected in 5 mL sterile test tubes and serum was separated and stored at -20°C for further serological examination.

2.5. Serological examination of T. gondii

The serum of human were analysed for T. gondii IgM antibodies and IgG antibodies using commercially available Toxo- IgM kit (BioCheck Inc. USA, Catalog Number: BC-1087) and Toxo-IgG kit (BioCheck, Inc. USA, Catalog Number BC-1085) according to the manufacturer’s instructions. The microwell plate of ELISA was read by a Microplate reader with O.D at 450 nm (Microplate Reader, Model Dia 710 UK). The serum of animals were analysed by using Commercial ELISA Kits (ID Screen Toxoplasmosis Indirect®ID-VET Company, France) for the detection of Toxo-IgG and Toxo-IgM antibodies.

2.6. T. gondii DNA detection from milk

The extraction of DNA from milk was carried out by using a DNA isolation kit (Favorgen Tissue Genomic DNA Extraction Mini kit, USA). The extracted DNA was amplified by using primers of B1 gene for T. gondii following the protocol of Sadek et al. (2015)SADEK, O.A., ABDEL-HAMEED, Z.M. and KURAA, H.M., 2015. Molecular detection of Toxoplasma gondii DNA in Raw Goat and Sheep milk with discussion of its Public Health Importance in Assiut Governorate. Assiut Veterinary Medical Journal, vol. 61, no. 145, pp. 166-177.http://dx.doi.org/10.21608/avmj.2015.170200.
http://dx.doi.org/10.21608/avmj.2015.170...
. The reaction conditions consisted of one cycle of 95ºC for 5 minutes followed by 40 cycles of 94ºC for 30 seconds, 60ºC for 30 seconds, 72ºC for 1 minute, and final extension at 72ºC for 10 minutes, and then the amplified DNA were electrophoresed on 2% agarose gel. The amplified DNA 115 bp bands were visualized under UV- trans illuminator and compared with a 50 bp DNA ladder marker (thermoisher scientific, USA).

2.7. Data analysis

The data were analyzed by using SPSS version 20. Chi-square test (X2) was used to assess the associations between Toxoplasma seropositive and the studied factors. A p-value less than 0.05 was considered statistically significant. The frequency of Toxoplasma DNA in milk samples was analyzed in four age groups of animals (≤5 years, 6-9 years, 10-12 years, and ≥13 years. Age-wise sero-prevalence of T. gondii was analyzed in the different age groups of humans (5-20 years, 21-35 years, 36-50 years, and ≥51 years).

3. Result

3.1. Toxoplasma in animals

The serological examination of the serum samples showed the presence of T. gondii antibodies (IgM and IgG) while PCR analysis showed the presence of T. gondii DNA in the unpasteurized milk samples of lactating animal. The overall prevalence for T. gondii IgM was 32.18% (n=75), IgG was 17.16% (n=40), while both IgG and IgM was 6.4% (n=15). Out of 76 sheep, IgM positivity was 38.16% (n=29), IgG was 21.05% (n=16), and both IgG and IgM was 6.5% (n=5). Of 69 goats, 34.78% (n=24) were positive for IgM, 21.74% (n=15) for IgG, and 8.6% (n=6) for both IgG and IgM. Of 50 cows , 24.4% (n=12), 10% (n=5), and 4% (n=2) were positive for IgM, IgG, and both IgG and IgM, respectively. In 38 buffaloes, 26.31% (n=10) were positive for IgM, 10.53% (n=4) for IgG and 26.0% (n=2) were reported positive for both IgG and IgM.

Through PCR, 23.60% (55/233) milk samples were found positive for T.gondii DNA. Of the positive samples, 14.47% (n=11) sheep, 34.80% (n=24) goats, 20% (n=10) cows and 26.31% (n=10) buffaloes. Interestingly, DNA was found positive in the milk samples of sheep (n=4), goats (n=14), cows (n=6) and buffaloes (n=3) whose blood were negative for IgM+IgG (p=0.477). Prevalence of T. gondii antibodies (IgM and IgG) and DNA in milk of lactating animals in Upper Dir district was shown in Table 1).

Table 1
Prevalence of T. gondii antibodies (IgM and IgG) and DNA in milk of lactating animals in Upper Dir district.

The distribution of positive antibodies in blood of animals and DNA of milk was showed in Table 2. The positive results of PCR (23.60%) were significantly higher than those of IgG (10.73%) but lower than IgM (25.75%). The proof of DNA in milk samples by PCR in both IgG positive animals and IgM positive animals were statistically significant (p=0.0002 and p=0.0092, respectively) in comparison to concurrent presence IgG and IgM. Goats were reported with high prevalence (34.8%) of T. gondii DNA in their milk as compared to other animals.

Table 2
Comparative analysis of T. gondii antibodies and DNA in Upper Dir district.

The frequency of Toxoplasma DNA in studied animals in age groups ≤5 years, 6-9 years, 10-12 years, and ≥13 years was 20.48%, 25.55%, 27.02%, and 38.49%, respectively. Statistically, T. gondii DNA positivity increased non-significantly (p=1.195) with age in all animals studied (Table 3).

Table 3
T. gondii DNA in lactating animals by PCR in Upper Dir district.

Different risk factors of acquiring the parasite related to the IgM in positive and negative cases were also analyzed. It was found that contact with cats (p =0.9282), drinking water source (p=0.0955) and poor hygiene condition (p =0.39551) were not significant risk factor while feeding habits (p < 0.0001) of animals was associated with T. gondii infections (Table 4).

Table 4
Risk factors related prevalence for T. gondii in lactating animals in Upper Dir district.

3.2. Toxoplasma in human

A total of 735 human blood samples (350 males and 385 females) were also analyzed for T. gondii infection. The overall seroprevalence of IgM and IgG were 9.8% (n=72) and 11.2% (n=82), respectively, while none was found positive for both IgM and IgG. In the male population, the prevalence of IgM was 8.5% (n=30/350) and IgG was 9.7% =(34/350), while in females, the seroprevalence of IgM was10.9% (n=42/385) and IgG was 12.4% (n=48/385). (Table 5).

Table 5
Overall seroprevalence of T.gondii in human population in Upper Dir district.

The prevalence of T. gondii infection in the human population was given in Table 6. Results of this study indicated that toxoplasmosis infections significantly increase with age in both male (p=0.02) and female (p=0.01) populations.

Table 6
Age-wise sero-prevalence of T. gondii in human population in Upper Dir district.

4. Discussion

In the current study, the reported sero-prevalence of IgM was 32.18%, IgG was 17.16% and both IgM and IgG was 6.4% of the studied animals. The prevalence of T. gondii DNA in the milk of studied animals was 23.60%. The prevalence of T. gondii DNA in the milk samples varies in different age groups, ranging from 16.66% in animals aged ≤5 years, 11.76% in 6-9 years, and the prevalence increase with the age of the animals. The present study was consistent with a previous study from the United Kingdom that old age animals were less resistant to T. gondii infection than younger animals due to low immunity and high susceptibility to infection (Schares et al., 2017SCHARES, G., BANGOURA, B., RANDAU, F., GOROLL, T., LUDEWIG, M., MAKSIMOV, P., MATZKEIT, B., SENS, M., BÄRWALD, A., CONRATHS, F.J., OPSTEEGH, M. and VAN DER GIESSEN, J., 2017. High seroprevalence of Toxoplasma gondii and probability of detecting tissue cysts in backyard laying hens compared with hens from large free-range farms. International Journal for Parasitology, vol. 47, no. 12, pp. 765-777. http://dx.doi.org/10.1016/j.ijpara.2017.07.003. PMid:28870755.
http://dx.doi.org/10.1016/j.ijpara.2017....
).

Several past studies reported low prevalence of T. gondii DNA in sheep milk samples than the present study; 3.4% prevalence rate reported from Italy (Fusco et al., 2007FUSCO, G., RINALDI, L., GUARINO, A., PROROGA, Y.T., PESCE, A., GIUSEPPINA, M. and CRINGOLI, G., 2007. Toxoplasma gondii in sheep from the Campania region (Italy). Veterinary Parasitology, vol. 149, no. 3-4, pp. 271-274. http://dx.doi.org/10.1016/j.vetpar.2007.07.020. PMid:17764846.
http://dx.doi.org/10.1016/j.vetpar.2007....
), 5% reported from Brazil (Camossi et al., 2011CAMOSSI, L.G., GRECA-JÚNIOR, H., CORRÊA, A.P.F.L., RICHINI-PEREIRA, V.B., SILVA, R.C., DA SILVA, A.V. and LANGONI, H., 2011. Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes. Veterinary Parasitology, vol. 177, no. 3-4, pp. 256-261. http://dx.doi.org/10.1016/j.vetpar.2010.12.007. PMid:21216534.
http://dx.doi.org/10.1016/j.vetpar.2010....
), 6.48% from Iran (Dehkordi et al., 2013DEHKORDI, F.S., BORUJENI, M.R., RAHIMI, E. and ABDIZADEH, R., 2013. Detection of Toxoplasma gondii in raw caprine, ovine, buffalo, bovine, and camel milk using cell cultivation, cat bioassay, capture ELISA, and PCR methods in Iran. Foodborne Pathogens and Disease, vol. 10, no. 2, pp. 120-125. http://dx.doi.org/10.1089/fpd.2012.1311. PMid:23441913.
http://dx.doi.org/10.1089/fpd.2012.1311...
), the difference between the present study and -mentioned studies might be due to variation in cat density, contaminated water and grasses with T. gondii oocysts, and geographic factors, etc. The current study supported result reported from Serbia that constant contact of sheep to the environment progressively increases the risk of T. gondii infection with the age of the sheep because the environment was contaminated with T. gondii oocysts (Stelzer et al., 2019STELZER, S., BASSO, W., SILVÁN, J.B., ORTEGA-MORA, L.M., MAKSIMOV, P., GETHMANN, J., CONRATHS, F.J., and SCHARES, G., 2019. Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact. Food and Waterborne Parasitology, vol. 15, e00037. https://doi.org/10.1016/j.fawpar.2019.e00037.
https://doi.org/10.1016/j.fawpar.2019.e0...
). The sero-prevalence reported from Southern Punjab Pakistan in sheep was 19.88%, which was lower than the present study (Hanif and Tasawar, 2016HANIF, M. and TASAWAR, Z., 2016. Seroprevalence and risk factors associated with toxoplasmosis in sheep in Multan and Khanewal districts of Punjab (Pakistan). Journal of Animal & Plant Sciences, vol. 26, no. 6, pp. 1620-1627.). Likewise, sero-prevalence reported in sheep was 36% from Mohmand agency, Pakistan (Thai et al., 2019), and 31.45% from Ethiopia (Gebremedhin and Gizaw, 2014GEBREMEDHIN, E.Z. and GIZAW, D., 2014. Seroprevalence of Toxoplasma gondii infection in sheep and goats in three districts of Southern Nations, Nationalities and Peoples’ Region of Ethiopia. World Applied Sciences Journal, vol. 31, no. 11, pp. 1891-1896.). The molecular prevalence of T. gondii DNA reported in sheep from Egypt was10.71% (Camossi et al., 2011CAMOSSI, L.G., GRECA-JÚNIOR, H., CORRÊA, A.P.F.L., RICHINI-PEREIRA, V.B., SILVA, R.C., DA SILVA, A.V. and LANGONI, H., 2011. Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes. Veterinary Parasitology, vol. 177, no. 3-4, pp. 256-261. http://dx.doi.org/10.1016/j.vetpar.2010.12.007. PMid:21216534.
http://dx.doi.org/10.1016/j.vetpar.2010....
), which was similar to current work.

In lactating goats in this study, the sero-prevalence rate of IgM was 34.78%, IgG was 21.74% and both IgM and IgG were 8.6% by ELISA. DNA of T. gondii detected in raw milk by PCR was 34.78%. The age of the lactating goats were evaluated for the relationship with T. gondii occurrence. Similar results were also reported from Ethiopia in old age caprine have high toxoplasmosis (Teshale et al., 2007TESHALE, S., DUMETRE, A., DARDE, M.L., MERGA, B. and DORCHIES, P., 2007. Serological survey of caprine toxoplasmosis in Ethiopia: prevalence and risk factors. Parasite (Paris, France), vol. 14, no. 2, pp. 155-159. PMid:17645188.), which justified the present study.

Data reported by several investigators in lactating goat milk from different countries of the world; such as from Egypt, the prevalence of T. gondii DNA through PCR was 22.73% (Camossi et al., 2011CAMOSSI, L.G., GRECA-JÚNIOR, H., CORRÊA, A.P.F.L., RICHINI-PEREIRA, V.B., SILVA, R.C., DA SILVA, A.V. and LANGONI, H., 2011. Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes. Veterinary Parasitology, vol. 177, no. 3-4, pp. 256-261. http://dx.doi.org/10.1016/j.vetpar.2010.12.007. PMid:21216534.
http://dx.doi.org/10.1016/j.vetpar.2010....
), and from El-Fayoum Governorate, Egypt was 25% (Ghoneim et al., 2009GHONEIM, N.S.S., HASSANAIN, N., ZEEDAN, G., SOLIMAN, Y. and ABDALHAMED, A., 2009. Detection of genomic Toxoplasma gondii DNA and anti-Toxoplasma antibodies in high risk women and contact animals. Global Veterinaria, vol. 3, no. 5, pp. 395-400.), from Brazil was 28.9% (Bisson et al., 2000BISSON, A., MALEY, S., RUBAIRE-AKIIKI, C.M. and WASTLING, J.M., 2000. The seroprevalence of antibodies to Toxoplasma gondii in domestic goats in Uganda. Acta Tropica, vol. 76, no. 1, pp. 33-38. http://dx.doi.org/10.1016/S0001-706X(00)00086-3. PMid:10913763.
http://dx.doi.org/10.1016/S0001-706X(00)...
), from Thailand was 27.9% (Jittapalapong et al., 2005JITTAPALAPONG, S., SANGVARANOND, A., PINYOPANUWAT, N., CHIMNOI, W., KHACHAERAM, W., KOIZUMI, S. and MARUYAMA, S., 2005. Seroprevalence of Toxoplasma gondii infection in domestic goats in Satun Province, Thailand. Veterinary Parasitology, vol. 127, no. 1, pp. 17-22. http://dx.doi.org/10.1016/j.vetpar.2004.08.019. PMid:15619370.
http://dx.doi.org/10.1016/j.vetpar.2004....
), from Pakistan was 25.4% (Ramzan et al., 2009RAMZAN, M., AKHTAR, M., MUHAMMAD, F., HUSSAIN, I., HISZCZYNSKA-SAWICKA, E., HAQ, A.U., MAHMOOD, M.S. and HAFEEZ, M.A., 2009. Seroprevalence of Toxoplasma gondii in sheep and goats in Rahim Yar Khan (Punjab), Pakistan. Tropical Animal Health and Production, vol. 41, no. 7, pp. 1225-1229. http://dx.doi.org/10.1007/s11250-009-9304-0. PMid:19225903.
http://dx.doi.org/10.1007/s11250-009-930...
), and from Slovakia was 32.56% T. gondii DNA reported in goats milk (Spišák et al., 2010SPIŠÁK, F., TURČEKOVÁ, Ľ., REITEROVÁ, K., ŠPILOVSKÁ, S. and DUBINSKÝ, P., 2010. Prevalence estimation and genotypization of T. gondii in goats. Biologia, vol. 65, no. 4, pp. 670-674. http://dx.doi.org/10.2478/s11756-010-0070-2.
http://dx.doi.org/10.2478/s11756-010-007...
), which showed coherence with the present study.

Likewise, the prevalence of T. gondii DNA reported by several authors through PCR technique from different countries such as 6.05% in raw milk of goat from Brazil (Bezerra et al., 2015BEZERRA, M.J.G., KIM, P.C.P., MORAES, É.P., SÁ, S.G., ALBUQUERQUE, P.P.F., SILVA, J.G., ALVES, B.H.L.S. and MOTA, R.A., 2015. Detection of T oxoplasma gondii in the milk of naturally infected goats in the N ortheast of B razil. Transboundary and Emerging Diseases, vol. 62, no. 4, pp. 421-424. http://dx.doi.org/10.1111/tbed.12160. PMid:24034351.
http://dx.doi.org/10.1111/tbed.12160...
), and 13% of T. gondii DNA recorded in naturally infected lactating goats from Italy (Mancianti et al., 2013MANCIANTI, F., NARDONI, S., D’ASCENZI, C., PEDONESE, F., MUGNAINI, L., FRANCO, F. and PAPINI, R., 2013. Seroprevalence, detection of DNA in blood and milk, and genotyping of Toxoplasma gondii in a goat population in Italy. BioMed Research International, vol. 2013, pp. 905326. http://dx.doi.org/10.1155/2013/905326. PMid:24093106.
http://dx.doi.org/10.1155/2013/905326...
). Data reported from Northwest Tunisia that consuming raw goats’ milk represents a real risk factor for human toxoplasmosis (Amairia et al., 2016AMAIRIA, S., ROUATBI, M., RJEIBI, M.R., NOUASRI, H., SASSI, L., MHADHBI, M. and GHARBI, M., 2016. Molecular prevalence of Toxoplasma gondii DNA in goats’ milk and seroprevalence in Northwest Tunisia. Veterinary Medicine and Science, vol. 2, no. 3, pp. 154-160. http://dx.doi.org/10.1002/vms3.29. PMid:29067190.
http://dx.doi.org/10.1002/vms3.29...
). The reported prevalence of T. gondii DNA from Northwest of Iran was 9.44% in the raw milk of goats (Tavassoli et al., 2013TAVASSOLI, M., ESMAEILNEJAD, B., MALEKIFARD, F., SOLEIMANZADEH, A. and DILMAGHANI, M., 2013. Detection of T. gondii DNA in sheep and goat milk in Northwest of Iran by PCR-RFLP. Jundishapur Journal of Microbiology, vol. 6, no. 10, pp. e8201. http://dx.doi.org/10.5812/jjm.8201.
http://dx.doi.org/10.5812/jjm.8201...
). The sero-prevalence reported in goats from Multan Pakistan was 52% (Tasawar et al., 2011TASAWAR, Z., LASHARI, H.M., HANIF, M. and HAYAT, S.C., 2011. Seroprevalence of Toxoplasma gondiiin Domestic Goats in Multan Punjab, Pakistan. Pakistan Journal of Life and Social Sciences, vol. 9, no. 1, pp. 24-27.), while from Zimbabwe the prevalence rate reported was 67.9% (Hove et al., 2005HOVE, T., LIND, P. and MUKARATIRWA, S., 2005. Seroprevalence of Toxoplasma gondii infection in goats and sheep in Zimbabwe. The Onderstepoort Journal of Veterinary Research, vol. 72, no. 4, pp. 267-272. http://dx.doi.org/10.4102/ojvr.v72i4.175. PMid:16562728.
http://dx.doi.org/10.4102/ojvr.v72i4.175...
) and from Egypt was 59.4% (Barakat et al., 2009BARAKAT, A.M.A., ELAZIZ, M.A. and FADALY, H.A., 2009. Comparative diagnosis of toxoplasmosis in Egyptian small ruminants by indirect hemagglutination assay and Elisa. Global Veterinaria, vol. 3, no. 1, pp. 9-14.). Detection of toxoplasmosis in different lactating species (goats, sheep, buffalos, cattle, and camels) was recently studied in Iran with different techniques and reported that the raw milk of the mentioned animal contains T. gondii (Dehkordi et al., 2013DEHKORDI, F.S., BORUJENI, M.R., RAHIMI, E. and ABDIZADEH, R., 2013. Detection of Toxoplasma gondii in raw caprine, ovine, buffalo, bovine, and camel milk using cell cultivation, cat bioassay, capture ELISA, and PCR methods in Iran. Foodborne Pathogens and Disease, vol. 10, no. 2, pp. 120-125. http://dx.doi.org/10.1089/fpd.2012.1311. PMid:23441913.
http://dx.doi.org/10.1089/fpd.2012.1311...
). Therefore, the unpasteurized milk of the said animals is a risk factor for T. gondii transmission to humans. In the current study, the molecular prevalence of T. gondii DNA was detected higher in goat milk as compared to other lactating animals included in the study population. A similar result was also reported by other authors that the milk of infected goat contains more T. gondii tachyzoites as compared to its meat (Spišák et al., 2010SPIŠÁK, F., TURČEKOVÁ, Ľ., REITEROVÁ, K., ŠPILOVSKÁ, S. and DUBINSKÝ, P., 2010. Prevalence estimation and genotypization of T. gondii in goats. Biologia, vol. 65, no. 4, pp. 670-674. http://dx.doi.org/10.2478/s11756-010-0070-2.
http://dx.doi.org/10.2478/s11756-010-007...
; Bezerra et al., 2015BEZERRA, M.J.G., KIM, P.C.P., MORAES, É.P., SÁ, S.G., ALBUQUERQUE, P.P.F., SILVA, J.G., ALVES, B.H.L.S. and MOTA, R.A., 2015. Detection of T oxoplasma gondii in the milk of naturally infected goats in the N ortheast of B razil. Transboundary and Emerging Diseases, vol. 62, no. 4, pp. 421-424. http://dx.doi.org/10.1111/tbed.12160. PMid:24034351.
http://dx.doi.org/10.1111/tbed.12160...
).

The high prevalence of T. gondii in lactating goats in the present research may be due to different climatic factors such as high humidity, temperature change, the difference in agro-ecology, high density of dogs and cats.

In the current study, the examined sero-prevalence in lactating cows through ELISA; IgM was 24%, IgG was 10% and both IgM and IgG was 4%. DNA of T. gondii was detected in raw milk of cow by PCR with the prevalence of 20%. In the different age groups of cows showed that the prevalence of T. gondii DNA considerably increases with the age of the cow. The present research was coherent with the reported prevalence in cows from different countries such as 20% from Mohmand agency, Pakistan (Shah et al., 2013SHAH, M., ZAHID, M., STHANADAR, A.A., PIR, A., KAUSAR, A. and JAN, A.H., 2013. Seroprevalence of Toxoplasmagondii infection in domestic animals of Mohmand agency, Pakistan. Journal of Coastal Life Medicine, vol. 1, pp. 70-73.), 13.3% by ELISA from Sudan (Elfahal et al., 2013ELFAHAL, A.M., ELHASSAN, A.M., HUSSIEN, M.O., ENAN, K.A., MUSA, A.B. and EL HUSSEIN, A.M., 2013. Seroprevalence of Toxoplasma gondii in dairy cattle with reproductive problems in Sudan. ISRN Veterinary Science, vol. 2013, pp. 895165. http://dx.doi.org/10.1155/2013/895165. PMid:24171116.
http://dx.doi.org/10.1155/2013/895165...
), 15.91% from Iran (Delgado et al., 2022DELGADO, I.L.S., ZÚQUETE, S., SANTOS, D., BASTO, A.P., LEITÃO, A. and NOLASCO, S., 2022. The Apicomplexan parasite Toxoplasma gondii. Encyclopedia, vol. 2, no. 1, pp. 189-211. http://dx.doi.org/10.3390/encyclopedia2010012.
http://dx.doi.org/10.3390/encyclopedia20...
), and all these support the present study. While the reported prevalence of T. gondii in cattle from Serbia the estimated prevalence of T. gondii was observed 76.3% in cattle (Klun et al., 2006KLUN, I., DJURKOVIĆ-DJAKOVIĆ, O., KATIĆ-RADIVOJEVIĆ, S. and NIKOLIĆ, A., 2006. Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep and pigs in Serbia: seroprevalence and risk factors. Veterinary Parasitology, vol. 135, no. 2, pp. 121-131. http://dx.doi.org/10.1016/j.vetpar.2005.08.010. PMid:16188388.
http://dx.doi.org/10.1016/j.vetpar.2005....
), and from Brazil, 71% prevalence of T. gondii was reported in cattle (Santos et al., 2009SANTOS, T.R., COSTA, A.J., TONIOLLO, G.H., LUVIZOTTO, M.C.R., BENETTI, A.H., SANTOS, R.R., MATTA, D.H., LOPES, W.D.Z., OLIVEIRA, J.A. and OLIVEIRA, G.P., 2009. Prevalence of anti-Toxoplasma gondii antibodies in dairy cattle, dogs, and humans from the Jauru micro-region, Mato Grosso state, Brazil. Veterinary Parasitology, vol. 161, no. 3-4, pp. 324-326. http://dx.doi.org/10.1016/j.vetpar.2009.01.017. PMid:19232473.
http://dx.doi.org/10.1016/j.vetpar.2009....
) which was extremely higher than the present study.

The sero-prevalence reported in lactating buffalo was 26.31% for IgM, 10.53% for IgG, and 6.4% for both IgG and IgM by ELISA. DNA of T. gondii detected by PCR was 26.0% in unpasteurized milk of buffalo. In the different age groups of buffalo, the prevalence of T. gondii DNA ranges such as, the positivity of 10% was reported in buffalo of age group II, 26.66% in age group III while 38.66% in age group IV. The frequency significantly increases with the age of the buffalo (p<0.05).

There are limited reports throughout the world on the sero-prevalence of T. gondii infection in buffaloes (Shah et al., 2013SHAH, M., ZAHID, M., STHANADAR, A.A., PIR, A., KAUSAR, A. and JAN, A.H., 2013. Seroprevalence of Toxoplasmagondii infection in domestic animals of Mohmand agency, Pakistan. Journal of Coastal Life Medicine, vol. 1, pp. 70-73.). Current study was supported by 27.2% sero-prevalence reported from Brazil (Oliveira et al., 2018OLIVEIRA, J.P., CASSEB, A.R., RAMOS, A.S., ROLIM FILHO, S.T., NOGUEIRA, H.L., PINHO, R.O. and PEREIRA, W.L.A., 2018. Risk factors associated with the epidemiology of Toxoplasma gondii in cattle and buffaloes in the state of Pará, Brazil. Semina: Ciências Agrárias, vol. 39, no. 5, pp. 2029-2037. http://dx.doi.org/10.5433/1679-0359.2018v39n5p2029.
http://dx.doi.org/10.5433/1679-0359.2018...
), 7.8% reported from Trinidad (Persad et al., 2011PERSAD, A., CHARLES, R. and ADESIYUN, A.A., 2011. Frequency of toxoplasmosis in water buffalo (Bubalus bubalis) in Trinidad. Veterinary Medicine International, vol. 2011, pp. 705358. http://dx.doi.org/10.4061/2011/705358. PMid:22195295.
http://dx.doi.org/10.4061/2011/705358...
), 8.8% from Iran (Anvari et al., 2018ANVARI, D., SAADATI, D., NABAVI, R. and ALIPOUR ESKANDANI, M., 2018. Epidemiology and molecular prevalence of toxoplasma gondii in cattle slaughtered in Zahedan and Zabol Districts, South East of Iran. Iranian Journal of Parasitology, vol. 13, no. 1, pp. 114-119. PMid:29963093.). Several risk factors including sex, diagnostic test, age, and climatic alterations probably take part in changing the prevalence in buffaloes throughout the globe (Ahmad and Qayyum, 2014AHMAD, N. and QAYYUM, M., 2014. Seroprevalence and risk factors for toxoplasmosis in large ruminants in northern Punjab, Pakistan. Journal of Infection in Developing Countries, vol. 8, no. 8, pp. 1022-1028. http://dx.doi.org/10.3855/jidc.4405. PMid:25116669.
http://dx.doi.org/10.3855/jidc.4405...
). The high prevalence of T. gondii infection in the present study might be due to differences in agro-ecology, climate, cat and dog density in the study area, sample size, unhygienic condition, animal management, contaminated water with oocysts, transmission routes, age of the animals and type of serological tests applied, etc. Animals reared for dairy production and reproduction often lives much longer. Therefore, T. gondii infection was higher in the milk of adult cattle than in the young cattle mentioning the reason that animals with longer life expectancy have longer exposure to risk factors, thus more contaminated with T. gondii parasite (Abdallah et al., 2019ABDALLAH, M.C., KAMEL, M., KARIMA, B., SAMIR, A., DJAMEL, K., RACHID, K. and KHATIMA, A.O., 2019. Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep, and goats in Algeria: seroprevalence and risk factors. Veterinary Sciences, vol. 6, no. 3, pp. 63. http://dx.doi.org/10.3390/vetsci6030063. PMid:31295942.
http://dx.doi.org/10.3390/vetsci6030063...
; Stelzer et al., 2019STELZER, S., BASSO, W., SILVÁN, J.B., ORTEGA-MORA, L.M., MAKSIMOV, P., GETHMANN, J., CONRATHS, F.J., and SCHARES, G., 2019. Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact. Food and Waterborne Parasitology, vol. 15, e00037. https://doi.org/10.1016/j.fawpar.2019.e00037.
https://doi.org/10.1016/j.fawpar.2019.e0...
), also supported current study. Moreover, in older age, animals are proven less resistant to pathogens due to low immunity and high susceptibility to infection than younger ones (Ahmad and Qayyum, 2014AHMAD, N. and QAYYUM, M., 2014. Seroprevalence and risk factors for toxoplasmosis in large ruminants in northern Punjab, Pakistan. Journal of Infection in Developing Countries, vol. 8, no. 8, pp. 1022-1028. http://dx.doi.org/10.3855/jidc.4405. PMid:25116669.
http://dx.doi.org/10.3855/jidc.4405...
; Roberts et al., 2001ROBERTS, C.W., WALKER, W., and ALEXANDER, J., 2001. Sex-associated hormones and immunity to protozoan parasites. Clinical Microbiology Reviews, vol. 14, vol. 3, pp. 476-488. http://dx.doi.org/10.1128/CMR.14.3.476-488.2001.
http://dx.doi.org/10.1128/CMR.14.3.476-4...
; Ahmed et al., 2016AHMED, H., MALIK, A., ARSHAD, M., MUSTAFA, I., KHAN, M.R., AFZAL, M.S., ALI, S., MOBEEN, M. and SIMSEK, S., 2016. Seroprevalence and spatial distribution of toxoplasmosis in sheep and goats in North-Eastern Region of Pakistan. Korean Journal of Parasitology, vol. 54, no. 4, pp. 439-446. http://dx.doi.org/10.3347/kjp.2016.54.4.439. PMid:27658595.
http://dx.doi.org/10.3347/kjp.2016.54.4....
).

The poor hygienic state may favor water and food to be contaminated with cat feces, hence it increased risk of T. gondii infection in the livestock. Because a small proportion of individuals acquired the infection, then pose a potential reservoir of infection. While the majority later infected by using contaminated food and drinking water. Thus good hygienic status and cleaning measures have a protective effect (Stelzer et al., 2019STELZER, S., BASSO, W., SILVÁN, J.B., ORTEGA-MORA, L.M., MAKSIMOV, P., GETHMANN, J., CONRATHS, F.J., and SCHARES, G., 2019. Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact. Food and Waterborne Parasitology, vol. 15, e00037. https://doi.org/10.1016/j.fawpar.2019.e00037.
https://doi.org/10.1016/j.fawpar.2019.e0...
).

In this study, 738 humans tested for T. gondii, 9.80% and 11.80% showed seropositivity to IgM and IgG, respectively, corresponding to an overall prevalence rate of 20.95%. This showed that T. gondii infection is highly prevalent in the study area. This region is an agricultural region and the people kept domestic animals for economic purposes. Cat and other pet animals are also generally kept in-home or near home, unhygienic nutritional tradition and low education level contributes to infection. The prevalence rate of T. gondii infection throughout the globe, as well as within-country, is variable since its prevalence depends upon the environment (water quality, sanitation, coverage, etc.), climatic variations from one region to another, socioeconomic (hygiene, source of food, etc.), climatic factors (humidity, temperature), lifestyle of the inhabitants (dietary habits, method of cooking, hand washing, kind of food item cleaning, contact with cats and dogs or other domestic animals, contact with the soil, etc.) and difference in serological tests with variable specificity and sensitivity (Tenter et al., 2000TENTER, A.M., HECKEROTH, A.R. and WEISS, L.M., 2000. Toxoplasma gondii: from animals to humans. International Journal for Parasitology, vol. 30, no. 12-13, pp. 1217-1258. http://dx.doi.org/10.1016/S0020-7519(00)00124-7. PMid:11113252.
http://dx.doi.org/10.1016/S0020-7519(00)...
; Robert-Gangneux and Dardé, 2012ROBERT-GANGNEUX, F. and DARDÉ, M.L., 2012. Epidemiology of and diagnostic strategies for toxoplasmosis. Clinical Microbiology Reviews, vol. 25, no. 2, pp. 264-296. http://dx.doi.org/10.1128/CMR.05013-11. PMid:22491772.
http://dx.doi.org/10.1128/CMR.05013-11...
). However, a statistically significant correlation between positive serology for T. gondii in humans and ingestion of goat milk also had been reported in the literature (Sroka et al., 2017SROKA, J., KUSYK, P., BILSKA-ZAJAC, E., KARAMON, J., DUTKIEWICZ, J., WOJCIK-FATLA, A., ZAJAC, V., STOJECKI, K., RÓŻYCKI, M. and CENCEK, T., 2017. Seroprevalence of Toxoplasma gondii infection in goats from the south-west region of Poland and the detection of T. gondii DNA in goat milk. Folia Parasitologica, vol. 64, pp. 023. http://dx.doi.org/10.14411/fp.2017.023. PMid:28783032.
http://dx.doi.org/10.14411/fp.2017.023...
).

5. Conclusions

High prevalence of T. gondii in milk samples indicates a potential risk for the transmission of T. gondii to human through raw unpasteurized milk consumption. Therefore, awareness regarding the transmission and prevention of the disease is crucial. In general, integrated strategies and measures should be implemented to prevent and control T. gondii infection in dairy animals as well as in human in the study area.

Acknowledgements

We would like to thank all the participants and owners of animals for their cooperation.

References

  • ABDALLAH, M.C., KAMEL, M., KARIMA, B., SAMIR, A., DJAMEL, K., RACHID, K. and KHATIMA, A.O., 2019. Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep, and goats in Algeria: seroprevalence and risk factors. Veterinary Sciences, vol. 6, no. 3, pp. 63. http://dx.doi.org/10.3390/vetsci6030063 PMid:31295942.
    » http://dx.doi.org/10.3390/vetsci6030063
  • AGUIRRE, A.A., LONGCORE, T., BARBIERI, M., DABRITZ, H., HILL, D., KLEIN, P.N., LEPCZYK, C., LILLY, E.L., MCLEOD, R., MILCARSKY, J., MURPHY, C.E., SU, C., VANWORMER, E., YOLKEN, R. and SIZEMORE, G.C., 2019. The one health approach to toxoplasmosis: epidemiology, control, and prevention strategies. EcoHealth, vol. 16, no. 2, pp. 378-390. http://dx.doi.org/10.1007/s10393-019-01405-7 PMid:30945159.
    » http://dx.doi.org/10.1007/s10393-019-01405-7
  • AHMAD, N. and QAYYUM, M., 2014. Seroprevalence and risk factors for toxoplasmosis in large ruminants in northern Punjab, Pakistan. Journal of Infection in Developing Countries, vol. 8, no. 8, pp. 1022-1028. http://dx.doi.org/10.3855/jidc.4405 PMid:25116669.
    » http://dx.doi.org/10.3855/jidc.4405
  • AHMED, H., MALIK, A., ARSHAD, M., MUSTAFA, I., KHAN, M.R., AFZAL, M.S., ALI, S., MOBEEN, M. and SIMSEK, S., 2016. Seroprevalence and spatial distribution of toxoplasmosis in sheep and goats in North-Eastern Region of Pakistan. Korean Journal of Parasitology, vol. 54, no. 4, pp. 439-446. http://dx.doi.org/10.3347/kjp.2016.54.4.439 PMid:27658595.
    » http://dx.doi.org/10.3347/kjp.2016.54.4.439
  • ALZAHEB, R.A., 2018. Seroprevalence of Toxoplasma gondii and its associated risk factors among women of reproductive age in Saudi Arabia: a systematic review and meta-analysis. International Journal of Women’s Health, vol. 10, pp. 537-544. http://dx.doi.org/10.2147/IJWH.S173640 PMid:30288126.
    » http://dx.doi.org/10.2147/IJWH.S173640
  • AMAIRIA, S., ROUATBI, M., RJEIBI, M.R., NOUASRI, H., SASSI, L., MHADHBI, M. and GHARBI, M., 2016. Molecular prevalence of Toxoplasma gondii DNA in goats’ milk and seroprevalence in Northwest Tunisia. Veterinary Medicine and Science, vol. 2, no. 3, pp. 154-160. http://dx.doi.org/10.1002/vms3.29 PMid:29067190.
    » http://dx.doi.org/10.1002/vms3.29
  • ANVARI, D., SAADATI, D., NABAVI, R. and ALIPOUR ESKANDANI, M., 2018. Epidemiology and molecular prevalence of toxoplasma gondii in cattle slaughtered in Zahedan and Zabol Districts, South East of Iran. Iranian Journal of Parasitology, vol. 13, no. 1, pp. 114-119. PMid:29963093.
  • BARAKAT, A.M.A., ELAZIZ, M.A. and FADALY, H.A., 2009. Comparative diagnosis of toxoplasmosis in Egyptian small ruminants by indirect hemagglutination assay and Elisa. Global Veterinaria, vol. 3, no. 1, pp. 9-14.
  • BEZERRA, M.J.G., KIM, P.C.P., MORAES, É.P., SÁ, S.G., ALBUQUERQUE, P.P.F., SILVA, J.G., ALVES, B.H.L.S. and MOTA, R.A., 2015. Detection of T oxoplasma gondii in the milk of naturally infected goats in the N ortheast of B razil. Transboundary and Emerging Diseases, vol. 62, no. 4, pp. 421-424. http://dx.doi.org/10.1111/tbed.12160 PMid:24034351.
    » http://dx.doi.org/10.1111/tbed.12160
  • BISSON, A., MALEY, S., RUBAIRE-AKIIKI, C.M. and WASTLING, J.M., 2000. The seroprevalence of antibodies to Toxoplasma gondii in domestic goats in Uganda. Acta Tropica, vol. 76, no. 1, pp. 33-38. http://dx.doi.org/10.1016/S0001-706X(00)00086-3 PMid:10913763.
    » http://dx.doi.org/10.1016/S0001-706X(00)00086-3
  • CAMOSSI, L.G., GRECA-JÚNIOR, H., CORRÊA, A.P.F.L., RICHINI-PEREIRA, V.B., SILVA, R.C., DA SILVA, A.V. and LANGONI, H., 2011. Detection of Toxoplasma gondii DNA in the milk of naturally infected ewes. Veterinary Parasitology, vol. 177, no. 3-4, pp. 256-261. http://dx.doi.org/10.1016/j.vetpar.2010.12.007 PMid:21216534.
    » http://dx.doi.org/10.1016/j.vetpar.2010.12.007
  • CHAN, M.Y. and SMITH, M.A., 2018. Infections in pregnancy. In C.A. MCQUEEN, ed. Comprehensive toxicology USA: Elsevier, pp. 232-249. http://dx.doi.org/10.1016/B978-0-12-801238-3.64293-9
    » http://dx.doi.org/10.1016/B978-0-12-801238-3.64293-9
  • DEHKORDI, F.S., BORUJENI, M.R., RAHIMI, E. and ABDIZADEH, R., 2013. Detection of Toxoplasma gondii in raw caprine, ovine, buffalo, bovine, and camel milk using cell cultivation, cat bioassay, capture ELISA, and PCR methods in Iran. Foodborne Pathogens and Disease, vol. 10, no. 2, pp. 120-125. http://dx.doi.org/10.1089/fpd.2012.1311 PMid:23441913.
    » http://dx.doi.org/10.1089/fpd.2012.1311
  • DELGADO, I.L.S., ZÚQUETE, S., SANTOS, D., BASTO, A.P., LEITÃO, A. and NOLASCO, S., 2022. The Apicomplexan parasite Toxoplasma gondii. Encyclopedia, vol. 2, no. 1, pp. 189-211. http://dx.doi.org/10.3390/encyclopedia2010012
    » http://dx.doi.org/10.3390/encyclopedia2010012
  • DING, H., GAO, Y.M., DENG, Y., LAMBERTON, P.H. and LU, D.B., 2017. A systematic review and meta-analysis of the seroprevalence of Toxoplasma gondii in cats in mainland China. Parasites & Vectors, vol. 10, no. 1, pp. 27. http://dx.doi.org/10.1186/s13071-017-1970-6 PMid:28086987.
    » http://dx.doi.org/10.1186/s13071-017-1970-6
  • ELFAHAL, A.M., ELHASSAN, A.M., HUSSIEN, M.O., ENAN, K.A., MUSA, A.B. and EL HUSSEIN, A.M., 2013. Seroprevalence of Toxoplasma gondii in dairy cattle with reproductive problems in Sudan. ISRN Veterinary Science, vol. 2013, pp. 895165. http://dx.doi.org/10.1155/2013/895165 PMid:24171116.
    » http://dx.doi.org/10.1155/2013/895165
  • FOROUTAN, M., DALVAND, S., DARYANI, A., AHMADPOUR, E., MAJIDIANI, H., KHADEMVATAN, S. and ABBASI, E., 2018. Rolling up the pieces of a puzzle: a systematic review and meta-analysis of the prevalence of toxoplasmosis in Iran. Alexandria Journal of Medicine, vol. 54, no. 3, pp. 189-196. http://dx.doi.org/10.1016/j.ajme.2017.06.003
    » http://dx.doi.org/10.1016/j.ajme.2017.06.003
  • FURTADO, J.M., SMITH, J.R., BELFORT JUNIOR, R., GATTEY, D. and WINTHROP, K.L., 2011. Toxoplasmosis: a global threat. Journal of Global Infectious Diseases, vol. 3, no. 3, pp. 281-284. http://dx.doi.org/10.4103/0974-777X.83536 PMid:21887062.
    » http://dx.doi.org/10.4103/0974-777X.83536
  • FUSCO, G., RINALDI, L., GUARINO, A., PROROGA, Y.T., PESCE, A., GIUSEPPINA, M. and CRINGOLI, G., 2007. Toxoplasma gondii in sheep from the Campania region (Italy). Veterinary Parasitology, vol. 149, no. 3-4, pp. 271-274. http://dx.doi.org/10.1016/j.vetpar.2007.07.020 PMid:17764846.
    » http://dx.doi.org/10.1016/j.vetpar.2007.07.020
  • GALVAN-RAMIREZ, M.L., TROYO, R., ROMAN, S., CALVILLO-SANCHEZ, C. and BERNAL-REDONDO, R., 2012. A systematic review and meta-analysis of Toxoplasma gondii infection among the Mexican population. Parasites & Vectors, vol. 5, pp. 271. http://dx.doi.org/10.1186/1756-3305-5-271 PMid:23181616.
    » http://dx.doi.org/10.1186/1756-3305-5-271
  • GEBREMEDHIN, E.Z. and GIZAW, D., 2014. Seroprevalence of Toxoplasma gondii infection in sheep and goats in three districts of Southern Nations, Nationalities and Peoples’ Region of Ethiopia. World Applied Sciences Journal, vol. 31, no. 11, pp. 1891-1896.
  • GHONEIM, N.S.S., HASSANAIN, N., ZEEDAN, G., SOLIMAN, Y. and ABDALHAMED, A., 2009. Detection of genomic Toxoplasma gondii DNA and anti-Toxoplasma antibodies in high risk women and contact animals. Global Veterinaria, vol. 3, no. 5, pp. 395-400.
  • HANIF, M. and TASAWAR, Z., 2016. Seroprevalence and risk factors associated with toxoplasmosis in sheep in Multan and Khanewal districts of Punjab (Pakistan). Journal of Animal & Plant Sciences, vol. 26, no. 6, pp. 1620-1627.
  • HOVE, T., LIND, P. and MUKARATIRWA, S., 2005. Seroprevalence of Toxoplasma gondii infection in goats and sheep in Zimbabwe. The Onderstepoort Journal of Veterinary Research, vol. 72, no. 4, pp. 267-272. http://dx.doi.org/10.4102/ojvr.v72i4.175 PMid:16562728.
    » http://dx.doi.org/10.4102/ojvr.v72i4.175
  • JITTAPALAPONG, S., SANGVARANOND, A., PINYOPANUWAT, N., CHIMNOI, W., KHACHAERAM, W., KOIZUMI, S. and MARUYAMA, S., 2005. Seroprevalence of Toxoplasma gondii infection in domestic goats in Satun Province, Thailand. Veterinary Parasitology, vol. 127, no. 1, pp. 17-22. http://dx.doi.org/10.1016/j.vetpar.2004.08.019 PMid:15619370.
    » http://dx.doi.org/10.1016/j.vetpar.2004.08.019
  • KHAMSIAN, E.M., HAJIMOHAMMADI, B., ESLAMI, G., FALLAHZADEH, M.H. and HOSSEINI, S.S., 2021. Toxoplasma gondii in milk of human and goat from the desert area in Central Iran. Iranian Journal of Parasitology, vol. 16, no. 4, pp. 601-609. http://dx.doi.org/10.18502/ijpa.v16i4.7873 PMid:35082889.
    » http://dx.doi.org/10.18502/ijpa.v16i4.7873
  • KLUN, I., DJURKOVIĆ-DJAKOVIĆ, O., KATIĆ-RADIVOJEVIĆ, S. and NIKOLIĆ, A., 2006. Cross-sectional survey on Toxoplasma gondii infection in cattle, sheep and pigs in Serbia: seroprevalence and risk factors. Veterinary Parasitology, vol. 135, no. 2, pp. 121-131. http://dx.doi.org/10.1016/j.vetpar.2005.08.010 PMid:16188388.
    » http://dx.doi.org/10.1016/j.vetpar.2005.08.010
  • LASHARI, M.H., AFZAL, F., and FAROOQ, U., 2018. Hematological changes in free-range chicken (Gallus domesticus) naturally infected with Toxoplasma gondii Sarhad Journal of Agriculture, vol. 34, no. 4, 973-978. http://dx.doi.org/10.17582/journal.sja/2018/34.4.973.978
    » http://dx.doi.org/10.17582/journal.sja/2018/34.4.973.978
  • MANCIANTI, F., NARDONI, S., D’ASCENZI, C., PEDONESE, F., MUGNAINI, L., FRANCO, F. and PAPINI, R., 2013. Seroprevalence, detection of DNA in blood and milk, and genotyping of Toxoplasma gondii in a goat population in Italy. BioMed Research International, vol. 2013, pp. 905326. http://dx.doi.org/10.1155/2013/905326 PMid:24093106.
    » http://dx.doi.org/10.1155/2013/905326
  • MUKHOPADHYAY, D., ARRANZ-SOLÍS, D. and SAEIJ, J.P., 2020. Influence of the host and parasite strain on the immune response during Toxoplasma infection. Frontiers in Cellular and Infection Microbiology, vol. 10, pp. 580425. http://dx.doi.org/10.3389/fcimb.2020.580425 PMid:33178630.
    » http://dx.doi.org/10.3389/fcimb.2020.580425
  • OLIVEIRA, J.P., CASSEB, A.R., RAMOS, A.S., ROLIM FILHO, S.T., NOGUEIRA, H.L., PINHO, R.O. and PEREIRA, W.L.A., 2018. Risk factors associated with the epidemiology of Toxoplasma gondii in cattle and buffaloes in the state of Pará, Brazil. Semina: Ciências Agrárias, vol. 39, no. 5, pp. 2029-2037. http://dx.doi.org/10.5433/1679-0359.2018v39n5p2029
    » http://dx.doi.org/10.5433/1679-0359.2018v39n5p2029
  • OMONIJO, A.O., KALINDA, C. and MUKARATIRWA, S., 2022. Toxoplasma gondii Infections in Animals and humans in southern africa: a systematic review and meta-analysis. Pathogens (Basel, Switzerland), vol. 11, no. 2, pp. 183. http://dx.doi.org/10.3390/pathogens11020183 PMid:35215126.
    » http://dx.doi.org/10.3390/pathogens11020183
  • PERSAD, A., CHARLES, R. and ADESIYUN, A.A., 2011. Frequency of toxoplasmosis in water buffalo (Bubalus bubalis) in Trinidad. Veterinary Medicine International, vol. 2011, pp. 705358. http://dx.doi.org/10.4061/2011/705358 PMid:22195295.
    » http://dx.doi.org/10.4061/2011/705358
  • RAHIMI, M.T., DARYANI, A., SARVI, S., SHOKRI, A., AHMADPOUR, E., TESHNIZI, S.H., MIZANI, A. and SHARIF, M., 2015. Cats and Toxoplasma gondii: a systematic review and meta-analysis in Iran. The Onderstepoort Journal of Veterinary Research, vol. 82, no. 1, pp. e1-e10. http://dx.doi.org/10.4102/ojvr.v82i1.823 PMid:26017063.
    » http://dx.doi.org/10.4102/ojvr.v82i1.823
  • RAMZAN, M., AKHTAR, M., MUHAMMAD, F., HUSSAIN, I., HISZCZYNSKA-SAWICKA, E., HAQ, A.U., MAHMOOD, M.S. and HAFEEZ, M.A., 2009. Seroprevalence of Toxoplasma gondii in sheep and goats in Rahim Yar Khan (Punjab), Pakistan. Tropical Animal Health and Production, vol. 41, no. 7, pp. 1225-1229. http://dx.doi.org/10.1007/s11250-009-9304-0 PMid:19225903.
    » http://dx.doi.org/10.1007/s11250-009-9304-0
  • ROBERT-GANGNEUX, F. and DARDÉ, M.L., 2012. Epidemiology of and diagnostic strategies for toxoplasmosis. Clinical Microbiology Reviews, vol. 25, no. 2, pp. 264-296. http://dx.doi.org/10.1128/CMR.05013-11 PMid:22491772.
    » http://dx.doi.org/10.1128/CMR.05013-11
  • ROBERTS, C.W., WALKER, W., and ALEXANDER, J., 2001. Sex-associated hormones and immunity to protozoan parasites. Clinical Microbiology Reviews, vol. 14, vol. 3, pp. 476-488. http://dx.doi.org/10.1128/CMR.14.3.476-488.2001
    » http://dx.doi.org/10.1128/CMR.14.3.476-488.2001
  • ROUATBI, M., AMAIRIA, S., AMDOUNI, Y., BOUSSAADOUN, M.A., AYADI, O., AL-HOSARY, A.A.T., REKIK, M., BEN ABDALLAH, R., AOUN, K., DARGHOUTH, M.A., WIELAND, B. and GHARBI, M., 2019. Toxoplasma gondii infection and toxoplasmosis in North Africa: a review. Parasite (Paris, France), vol. 26, pp. 6. http://dx.doi.org/10.1051/parasite/2019006 PMid:30767889.
    » http://dx.doi.org/10.1051/parasite/2019006
  • RUHOOLLAH, KHAN, W., AL-JABR, O.A., KHAN, T., KHAN, A., EL-GHAREEB, W.R., AGUILAR-MARCELINO, L., HUSSEIN, E.O.S., ALHIMAIDI, A.R. and SWELUM, A.A., 2021. Prevalence of gastrointestinal parasite in small ruminants of District Dir Upper Khyber Pakhtunkhwa Province of Pakistan. Brazilian Journal of Biology = Revista Brasileira de Biologia, vol. 83, pp. e248978. https://doi.org/10.1590/1519-6984.248978
    » https://doi.org/10.1590/1519-6984.248978
  • SADEK, O.A., ABDEL-HAMEED, Z.M. and KURAA, H.M., 2015. Molecular detection of Toxoplasma gondii DNA in Raw Goat and Sheep milk with discussion of its Public Health Importance in Assiut Governorate. Assiut Veterinary Medical Journal, vol. 61, no. 145, pp. 166-177.http://dx.doi.org/10.21608/avmj.2015.170200
    » http://dx.doi.org/10.21608/avmj.2015.170200
  • SANCHEZ, S.G. and BESTEIRO, S., 2021. The pathogenicity and virulence of Toxoplasma gondii. Virulence, vol. 12, no. 1, pp. 3095-3114. http://dx.doi.org/10.1080/21505594.2021.2012346 PMid:34895084.
    » http://dx.doi.org/10.1080/21505594.2021.2012346
  • SANTOS, T.R., COSTA, A.J., TONIOLLO, G.H., LUVIZOTTO, M.C.R., BENETTI, A.H., SANTOS, R.R., MATTA, D.H., LOPES, W.D.Z., OLIVEIRA, J.A. and OLIVEIRA, G.P., 2009. Prevalence of anti-Toxoplasma gondii antibodies in dairy cattle, dogs, and humans from the Jauru micro-region, Mato Grosso state, Brazil. Veterinary Parasitology, vol. 161, no. 3-4, pp. 324-326. http://dx.doi.org/10.1016/j.vetpar.2009.01.017 PMid:19232473.
    » http://dx.doi.org/10.1016/j.vetpar.2009.01.017
  • SCHARES, G., BANGOURA, B., RANDAU, F., GOROLL, T., LUDEWIG, M., MAKSIMOV, P., MATZKEIT, B., SENS, M., BÄRWALD, A., CONRATHS, F.J., OPSTEEGH, M. and VAN DER GIESSEN, J., 2017. High seroprevalence of Toxoplasma gondii and probability of detecting tissue cysts in backyard laying hens compared with hens from large free-range farms. International Journal for Parasitology, vol. 47, no. 12, pp. 765-777. http://dx.doi.org/10.1016/j.ijpara.2017.07.003 PMid:28870755.
    » http://dx.doi.org/10.1016/j.ijpara.2017.07.003
  • SHAH, M., ZAHID, M., STHANADAR, A.A., PIR, A., KAUSAR, A. and JAN, A.H., 2013. Seroprevalence of Toxoplasmagondii infection in domestic animals of Mohmand agency, Pakistan. Journal of Coastal Life Medicine, vol. 1, pp. 70-73.
  • SHAPIRO, K., BAHIA-OLIVEIRA, L., DIXON, B., DUMÈTRE, A., DE WIT, L.A., VANWORMER, E. and VILLENA, I., 2019. Environmental transmission of Toxoplasma gondii: oocysts in water, soil and food. Food and Waterborne Parasitology, vol. 15, pp. e00049. http://dx.doi.org/10.1016/j.fawpar.2019.e00049 PMid:32095620.
    » http://dx.doi.org/10.1016/j.fawpar.2019.e00049
  • SHARIF, M., DARYANI, A., NASROLAHEI, M. and ZIAPOUR, S.P., 2009. Prevalence of Toxoplasma gondii antibodies in stray cats in Sari, northern Iran. Tropical Animal Health and Production, vol. 41, no. 2, pp. 183-187. http://dx.doi.org/10.1007/s11250-008-9173-y PMid:18473184.
    » http://dx.doi.org/10.1007/s11250-008-9173-y
  • SPIŠÁK, F., TURČEKOVÁ, Ľ., REITEROVÁ, K., ŠPILOVSKÁ, S. and DUBINSKÝ, P., 2010. Prevalence estimation and genotypization of T. gondii in goats. Biologia, vol. 65, no. 4, pp. 670-674. http://dx.doi.org/10.2478/s11756-010-0070-2
    » http://dx.doi.org/10.2478/s11756-010-0070-2
  • SROKA, J., KUSYK, P., BILSKA-ZAJAC, E., KARAMON, J., DUTKIEWICZ, J., WOJCIK-FATLA, A., ZAJAC, V., STOJECKI, K., RÓŻYCKI, M. and CENCEK, T., 2017. Seroprevalence of Toxoplasma gondii infection in goats from the south-west region of Poland and the detection of T. gondii DNA in goat milk. Folia Parasitologica, vol. 64, pp. 023. http://dx.doi.org/10.14411/fp.2017.023 PMid:28783032.
    » http://dx.doi.org/10.14411/fp.2017.023
  • STELZER, S., BASSO, W., SILVÁN, J.B., ORTEGA-MORA, L.M., MAKSIMOV, P., GETHMANN, J., CONRATHS, F.J., and SCHARES, G., 2019. Toxoplasma gondii infection and toxoplasmosis in farm animals: risk factors and economic impact. Food and Waterborne Parasitology, vol. 15, e00037. https://doi.org/10.1016/j.fawpar.2019.e00037
    » https://doi.org/10.1016/j.fawpar.2019.e00037
  • SUGDEN, K., MOFFITT, T.E., PINTO, L., POULTON, R., WILLIAMS, B.S. and CASPI, A., 2016. Is Toxoplasma Gondii Infection Related to Brain and Behavior Impairments in Humans? Evidence from a PopulationRepresentative Birth Cohort. PLoS One, vol. 11, no. 2, pp. e0148435. http://dx.doi.org/10.1371/journal.pone.0148435 PMid:26886853.
    » http://dx.doi.org/10.1371/journal.pone.0148435
  • TASAWAR, Z., LASHARI, H.M., HANIF, M. and HAYAT, S.C., 2011. Seroprevalence of Toxoplasma gondiiin Domestic Goats in Multan Punjab, Pakistan. Pakistan Journal of Life and Social Sciences, vol. 9, no. 1, pp. 24-27.
  • TAVASSOLI, M., ESMAEILNEJAD, B., MALEKIFARD, F., SOLEIMANZADEH, A. and DILMAGHANI, M., 2013. Detection of T. gondii DNA in sheep and goat milk in Northwest of Iran by PCR-RFLP. Jundishapur Journal of Microbiology, vol. 6, no. 10, pp. e8201. http://dx.doi.org/10.5812/jjm.8201
    » http://dx.doi.org/10.5812/jjm.8201
  • TENTER, A.M., HECKEROTH, A.R. and WEISS, L.M., 2000. Toxoplasma gondii: from animals to humans. International Journal for Parasitology, vol. 30, no. 12-13, pp. 1217-1258. http://dx.doi.org/10.1016/S0020-7519(00)00124-7 PMid:11113252.
    » http://dx.doi.org/10.1016/S0020-7519(00)00124-7
  • TESHALE, S., DUMETRE, A., DARDE, M.L., MERGA, B. and DORCHIES, P., 2007. Serological survey of caprine toxoplasmosis in Ethiopia: prevalence and risk factors. Parasite (Paris, France), vol. 14, no. 2, pp. 155-159. PMid:17645188.
  • THÁI, T.L., JUN, H., PARK, S.H., LÊ, H.G., LEE, J., AHN, S.K., KANG, J.M., MYINT, M.K., LIN, K., SOHN, W.M., NAM, H.W., NA, B.K. and KIM, T.S.. 2019. Seroprevalence of Toxoplasma gondii among School Children in Pyin Oo Lwin and Naung Cho, Upper Myanmar. Korean Journal of Parasitology, vol. 57, no. 3, pp. 303-308. http://dx.doi.org/10.3347/kjp.2019.57.3.303 PMid:31284355.
    » http://dx.doi.org/10.3347/kjp.2019.57.3.303
  • VAN DEN BROM, R., DE JONG, A., VAN ENGELEN, E., HEUVELINK, A. and VELLEMA, P., 2020. Zoonotic risks of pathogens from sheep and their milk borne transmission. Small Ruminant Research, vol. 189, pp. 106123. http://dx.doi.org/10.1016/j.smallrumres.2020.106123 PMid:32427176.
    » http://dx.doi.org/10.1016/j.smallrumres.2020.106123

Publication Dates

  • Publication in this collection
    13 Feb 2023
  • Date of issue
    2023

History

  • Received
    29 Aug 2022
  • Accepted
    15 Jan 2023
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