Frequency of gastrointestinal parasites in cats seen at the University of São Paulo Veterinary Hospital , Brazil

The frequency of gastrointestinal infections in 502 cats seen at the Veterinary Hospital of the University of São Paulo, SP, Brazil, between 2005 and 2014, was measured. The samples were analyzed using methods of flotation and sedimentation. The results were compared with those from studies published previously using fecal samples from the same hospital at different times. Associations between the frequency of positivity for each parasite and age, breed, sex, diarrhea and use of anthelmintic were investigated (chi-square or Fisher’s exact tests). A partitioned chi-square test was used to compare different periods. Cryptosporidium spp., Giardia spp., Cystoisospora spp. and Sarcocystis spp. were the most common parasites, followed by Toxocara cati and Ancylostoma spp. Cryptosporidium spp. presented higher frequency in young cats and Sarcocystis spp. with the presence of diarrhea (p < 0.05). Results from this study with previous periods showed that the frequencies of Cryptosporidium spp., Cystoisospora spp. and T. cati were lower (p < 0.05) than those observed in previous periods. The frequencies of Giardia spp. and Ancylostoma spp. were similar to the results found in the preceding period and lower than the values found for the other periods (p < 0.05). The reasons for these changes should be investigated.

According to the Brazilian Institute for Geography and Statistics (IBGE, 2015), there are 22.1 million domestic cats in Brazil, thus representing approximately 1.9 cats per household.However, in some regions of the country, studies on the prevalence of gastrointestinal parasites of cats are scarce or absent, and veterinarians have very little information for developing strategic control measures and treatments.
The aims of this study were to determine the frequency of gastrointestinal parasites in fecal samples from cats seen at a veterinary teaching hospital, in the metropolitan region of São Paulo, SP, Brazil, from 2005-2014, and compare this with results published previously (GENNARI et al., 1999(GENNARI et al., , 2001;;FUNADA et al., 2007), from the same diagnostic service since 1991.

Animals
The data used in the present study were obtained from single fecal samples from all cats examined for gastrointestinal parasites at the Parasitology Laboratory Service of the Veterinary Hospital (HOVET), University of São Paulo Veterinary School, São Paulo, SP, Brazil, from January 2005 to December 2014.The samples were collected by the owners, kept refrigerated and send to the laboratory within 12 hours after collection.
A total of 502 samples from domestic cats (i.e. with an owner) living in the metropolitan region of São Paulo were examined.Information relating to sex, breed (belonging or not belonging to a breed), age (< one year, ≥ one year), presence or absence of diarrhea and use of anthelmintics were available, but not for all the cat samples.Out of this total, it was known that 262 of the cats were male and 228 were female; 105 were young (< one year) and 340 were adults (≥ one year); 137 belonged to a breed and 349 did not belong to any defined breed; 170 presented diarrhea and 98 did not have diarrhea; and 148 had had anthelminthics administered previously and 87 had never used anthelminthics.

Diagnostic techniques
The routine diagnostic procedures used at the parasitological service consist of three methods: centrifugal sedimentation in water-ether (FERREIRA et al., 1962), flotation in sucrose solution (d = 1.203 g/cm 3 ) (OGASSAWARA & BENASSI, 1980) and flotation in saturated NaCl solution.Dipylidium caninum was diagnosed based on the presence of proglottids in feces.All the methods were qualitative, and the results were expressed as presence of parasites.

Statistical analyses
The frequency of positive cats and respective binomial 95% confidence intervals (CI) were calculated for each parasite.The associations between the frequencies of each parasite and the variables of age, breed, gender, occurrence of diarrhea and anthelmintic treatment were investigated using the chi-square or Fisher's exact tests (ZAR, 1999).A partitioned chi-square test was used to compare four periods (1991-1995; 1996-1999; 2000-2004; and 2005-2014) in relation to positivity for each parasite.P values < 0.05 were considered significant.All the analyses were performed using the BioEstat software (AYRES et al., 2007), version 5.03.
Table 2 presents the associations between each parasite and the variables analyzed.Cats aged less than one year and cats with diarrhea were associated with parasite infection (p < 0.05).When the parasites were analyzed individually, Cryptosporidium spp. was associated with age, such that there was higher frequency in young cats (p < 0.05), and Sarcocystis spp. with presence of diarrhea (p < 0.05).

Discussion
The cats used in the present study were client-owned cats under care at a university veterinary hospital.Therefore, the results represent this category of household cats, and comparisons with shelter or stray cat surveys should be made with caution.Previous studies on household, stray and shelter cats found significant lower occurrence in the group of owned animals (REMBIESA & RICHARDSON, 2003;SERRA et al., 2003;MCGLADE et al., 2003;JOFFE et al., 2011).However, in spite of having an owner and a home, some of those cats were free-roaming.They were allowed to go outdoors and thus became more exposed to sources of infection.They therefore represent a reservoir of parasites that are potentially zoonotic to humans and other companion animals.
After these three protozoa, the nematodes T. cati (11/502) and Ancylostoma spp.(7/502) were the next most frequent.With the exception of the results observed during the first period analyzed (1991)(1992)(1993)(1994)(1995), in which T. cati was among the three most common parasites, over the last 20 years the protozoa Cryptosporidium spp., Giardia spp.and Cystoisospora spp.have presented the highest frequencies in cats seen at HOVET.
Infections with more than one parasite were not very frequent, accounting for only 4.4% of all the samples examined, and the most common multiple infections were also between protozoa (Giardia spp.and Cryptosporidium spp.; and Giardia spp., Cryptosporidium spp.and Cystoisospora spp., each in 3/502).This result deserves special attention from veterinarians, who often use anthelmintics as a preventive control measure, without fecal examination.Several commercial anthelmintics did not show any effectiveness against protozoan parasites.
Although parasites of the genus Uncinaria have already been observed in stray cats in the city of Rio de Janeiro (UCHÔA et al., 1998), there is no description of this hookworm in dogs or cats from São Paulo, and, in this study, all diagnosed hookworm eggs were classified as Ancylostoma spp.
In the present study, the second most frequent nematode was Ancylostoma spp., which is considered to be the most prevalent nematode in dogs in Brazil (reviewed by LABRUNA et al., 2006), and also the one with the highest prevalence in cats in some Brazilian regions (SERRA et al., 2003;LABARTHE et al., 2004;COELHO et al., 2009;RAMOS et al., 2013;MONTEIRO et al., 2016).However, in all surveys on cats in the metropolitan region of São Paulo (OGASSAWARA et al., 1986;GENNARI et al., 1999GENNARI et al., , 2001;;RAGOZO et al., 2002;FUNADA et al., 2007) since 1986, Ancylostoma spp.has been the second most prevalent nematode, and in four of the five studies, T. cati occurrence was around three times higher than that of Ancylostoma spp., in both owned and shelter cats.
Platynosomum fastosum is a trematode that inhabits the hepatobiliary system of domestic and wild felids in tropical and subtropical regions (HEADLEY et al., 2011).In a retrospective study on cats seen at the University of Londrina Veterinary Hospital, in Paraná, Brazil, the most common pathological alterations associated with parasitism by P. fastosum were bile duct hypertrophy and adenomatous epithelial hyperplasia (HEADLEY et al., 2011).
In Brazil, pathological alterations due P. fastosum have also been described in cats in Bahia (SAMPAIO et al., 2006), São Paulo (XAVIER et al., 2007;CARREIRA et al., 2008) and Minas Gerais (VIEIRA et al., 2009).Compared with previous studies, in which this trematode was present with occurrence rates of 1.07% (GENNARI et al., 1999) and 0.3% (FUNADA et al., 2007), the rate of 0.8% found in the present period is almost unchanged.
Dipylidium caninum has been found to be very prevalent in all studies in which the animals were necropsied, because the whole proglottid, i. e. the diagnostic stage, is seldom seen in feces.By means of fecal examination, Martinez-Carrasco et al. (2007) found 1% of the dogs examined were positive, whereas necropsies on the same population showed that this tapeworm was present in 47% of the dogs.Thus, the findings from the present study, which were obtained through fecal examination, are certainly underestimates.
The protozoa Cryptosporidium spp., Giardia spp.and Cystoisospora spp.presented very similar occurrence rates in this study and were the most common parasites found in these cats.Similar results were observed in the two previous periods compared: 1991-1999(GENNARI et al., 1999, 2001) and 2000-2004(FUNADA et al., 2007).However, the values found in the present period were lower (p < 0.05) than those of the previous periods for Cryptosporidium spp.and Cystoisospora spp.For Giardia spp., although the occurrence rate was lower, this difference was not statistically significant.Ogassawara et al. (1986) and Ragozo et al. (2002), who both studied shelter cats in the metropolitan region of São Paulo, and Coelho et al. (2009), who studied shelter cats in Andradina, in the interior of the state of São Paulo, found that Cystoisospora spp.and Cryptosporidium spp.were the most frequent protozoan parasites.Their results thus confirm the present findings that cats in the state of São Paulo are frequently infected by these protozoa.
Cystoisospora spp.and Giardia spp.are also very frequent in cats in other regions of Brazil, with descriptions in Rio de Janeiro, Rio Grande do Sul, Paraná and Pernambuco (SERRA et al., 2003;TESSEROLLI et al., 2005;LORENZINI et al., 2007;MONTEIRO et al., 2016).According to Barutzki & Schaper (2011), Giardia spp. is one of the most prevalent parasites of cats in some regions of Europe.
Although Cryptosporidium spp.showed an association with age, such that it was more frequently found in young cats (< one year of age), Cystoisospora spp.and Giardia spp.were present in cats of all ages, with similar occurrence.This result indicates that routine fecal examinations are also important for older cats, and that preventive use of anthelminthics, without previous stool examination, may be very useful for helminth control.However, these treatments may not be effective for protozoan parasites, since several formulations show efficacy only in relation to helminths.The cause of reduction in the occurrence of many of these parasites in recent years, especially helminths, is difficult to explain based only on data that is sent along with fecal samples.There can be many causes, from the more constant use of anthelmintics for all life of animals, lower contact of cats with sources of infections, keeping them with less access to the streets, to the greater consciousness of the owners of health care, among others.
Although infections by Cryptosporidium spp.usually cause diarrhea, especially in young animals, in this study there was no association between the presence of diarrhea and Cryptosporidium spp.infection.The same result was previously described by Lucas & Hagiwara (1997) among cats in the metropolitan region of São Paulo.
According to Dubey et al. (2016), cats are definitive hosts for numerous Sarcocystis species.In the present study, 3.5% of the fecal samples presented Sarcocystis spp.sporocysts, and it was the only parasite in this study that presented an association with diarrhea (p < 0.05), such that 0.3% and 3.5% of the cats without and with diarrhea, respectively, were positive for these species.
Information about the use of anthelmintics was available for 235 cats.Out of this total, 148 (63%) had been administered anthelminthics previously and 87 (37%) had never used anthelminthics.At least one third of the owners were uninformed about the importance of anthelmintic treatment and control of endoparasites in their animals.
The cats in the present study were infected by potentially zoonotic parasites such as Giardia spp., Cryptosporidium spp., T. cati and Ancylostoma spp.Cats have an important role in the homes on which they live, often sharing with their owners the same locations in the house.This study provides information for veterinarians to be able to implement control measures, thereby not only acting on pets, but also reducing the risk of parasite transmission.

Table 1 .
Frequency of occurrence (with 95% CI) of gastrointestinal infection in fecal samples from 502 cats in the metropolitan region of São Paulo, according to parasite genus and species.

Table 3 .
Frequency of helminths and protozoa in fecal samples from cats seen at the Veterinary Hospital, University of São Paulo Veterinary School, São Paulo, SP, Brazil, from 1991 to 2014.