Prevalence of bovine fascioliasis and economic losses in an abattoir located in the state of Espírito Santo, Brazil

ABSTRACT: Bovine fasciolosis is a neglected parasitic zoonosis that causes economic losses to beef production chains due to liver condemnation at abattoirs. Despite the characterization of Bovine fasciolosis in several areas of Brazil, an update on its prevalence in the states of Rio de Janeiro and Espirito Santo is lacking. Thus, fasciolosis prevalence from 2018 to 2021 is presented here according to cattle origin (municipalities of both states). In addition, the associated economic impact on an abbatoir was analyzed through liver condemnation of bovines from both states. The prevalence of fasciolosis in the state of Espírito Santo (10.4%) was significantly higher than Rio de Janeiro (3.6%) (P < 0.01), and resulted in an economic loss of US$12,678.60 for the abattoir. The following municipalities located in the state of Espírito Santo presented prevalences above the mean (10.3%) established in the study: Vargem Alta, Anchieta, Cachoeiro do Itapemirim, Castelo, Atilio Vivacqua, Apiacá and Ibitirama. Thus, majority of these municipalities are considered high-risk areas. Although, there is an aparrent reduction of fasciolosis prevalence, it continues to be a cause of economic losses in abattoirs especially in the state of Espírito Santo. Accordingly, prophylactic measures must still be adopted in cattle farms.

http://doi.org/10.1590/0103-8478cr20220121 Fasciolosis is a neglected parasitic disease caused by the liver fluke Fasciola hepatica. The disease affects bovines and is widespread in Brazil (ALBUQUERQUE et al., 2022). Bovines with the parasite can present a decrease in body weight gain, poor welfare, and liver condemnation during meat inspection (ARIAS-PACHECO et al., 2020). Although, Fasciolosis is common in ruminants, reports of its incidence in other animals, such as capybaras, and humans have been reported in Brazil (PRITSCH & MOLENTO, 2018;MARTINS et al., 2021). The spatial distribution of this zoonotic disease is related to the presence of intermediate hosts (Lymnaea snails) (BENNEMA et al., 2017;SCHWANTES et al., 2019), which is influenced by climatic conditions (BENNEMA et al., 2017), and altitude (SILVA et al., 2020).
Ciência Rural, v.53, n.4, 2023. Teixeira et al. The presence of this parasite in bovine has been reported in several Brazilian States (BENNEMA et al., 2014). However, there is limited data in the literature about the epidemiology of fasciolosis in the state of Rio de Janeiro (PILE et al., 2001;BENNEMA et al., 2014) while this information is well-documented for the state of Espírito Santo (ALVES et al., 2011;BERNARDO et al., 2011;FREITAS et al., 2014;MARTINS et al., 2014). In this light, there is no recent study focused on fasciolosis prevalence according to cattle origin in these states and the analysis of its economic impact on abattoirs. Understanding the spatial distribution of fasciolosis is useful for a better comprehension of its epidemiology and establishment of priority areas requiring prophylactic strategies in Brazil (FREITAS et al., 2014;ALEIXO et al., 2015). Therefore, this study described fasciolosis prevalence from 2018 to 2021 according to the municipalities of cattle origin and the economic losses due to liver condemnation in an abattoir that slaughters bovines originating from the states of Espírito Santo and Rio de Janeiro. The abattoir is located in the Southern Region of Espírito Santo and is supervisioned by the state inspection agency (Institute of Agricultural and Forest Defense of Espírito Santo -IDAF). A total of 48,202 bovines were slaughtered and inspected in accordance with the standard meat production technology adopted in Brazil for cattle (BRAZIL, 1971). The animals were from 23 and 8 municipalities of the states of Espírito Santo and Rio de Janeiro, respectively ( Figure 1).
The data were obtained from spreadsheets containing registries of post mortem inspection condemnations. The inspection of the livers was performed through palpation, external surface observations and visualization of bile ducts through incisions (BRAZIL, 1971). In cases where F. hepatica was detected, the livers were considered unfit for human consumption (BRAZIL, 2017). To assess the economic losses due to condemnation, livers weighing 5 kg were considered and their commercial price was obtained from an abattoir (R$ 2.60 or US$ 0.51 per kg) located in the state of Espírito Santo, Brazil. Prevalence values were determined for each municipality using an individual cow as an epidemiological unit. At the state and municipality levels, the prevalence values were calculated by dividing the number of livers affected with Fasciola lesions by the total amount of slaughtered cattle. The 95% confidence intervals (CI) of prevalence values were calculated based on the Wilson's method using the binomial R package. The difference between the prevalences in the states of Rio de Janeiro and Espírito Santo was assessed using chi-square test (THRUSFIELD & CRHISTLEy, 2018).
The prevalence values of fasciolosis are shown in table 1 and figure 2. The prevalence of bovine fasciolosis in the state of Espírito Santo  (FREITAS et al., 2014). This prevalence is higher than other states, such as São Paulo The municipalities of Vargem Alta, Anchieta, Cachoeiro do Itapemirim, Castelo, Atilio Vivacqua, Apiacá and Ibitirama presented prevalences higher than the mean prevalence of this study (10.3%). A high prevalence has been previously reported in the municipalities of Vargem Alta (45%), Cachoeiro de Itapemirim (21.9 -36.50%), Atilio Vivacqua (28.9 -30.97%), Castelo (25%) and Apiacá (13%), but not for Ibitirama (ALVES et al., 2011;MARTINS et al., 2014). These municipalities are located in the Southern region of Espiríto Santo, considered a high-risk region for fasciolosis occurrence. It is known that the occurrence of fasciolosis in a certain area is related to the availability of adequate biotopes that allows the development of snails (FREITAS et al., 2014). Conversely, bovines from the municipalities of Divino de São Lourenço, Iúna, Mucurici, Araruama and Quissamã at the abattoir did not present parasites but based on the higher prevalence limits of the 95% confidence intervals the disease may occur in these areas.
Between 2006 and 2009, the abattoir lost US$381.875 US dollars due to the disease (BERNARDO et al., 2011), a higher value than that assessed in this study (US$12,678.60) ( Table 2). Besides a reduction in fasciolosis prevalence observed over the years, the economic losses of the beef production chain are persistent and cannot be considered irrelevant.
In conclusion, bovine fasciolosis continues to be a cause of economic losses among abattoirs in the state of Espírito Santo;, however an apparent reduction of its occurrence was observed. Thus, prophylactic practices must still be adopted in farms, such as limiting grazing in areas where flooding occurs, detecting positive animals and deworming them, and avoiding animals of different species in the same area (MARTINS et al., 2014).