Introduction

The cryptosporidiosis occurrence in dogs was determined because of the increasing importance of intestinal coccidian as an opportunist parasite and for its zoonotic potential defined by the narrow cohabitation between human beings and domestic animals. Cryptosporidiosis is a zoonoses caused by a protozoa of the genera Cryptosporidium, being Cryptosporidium parvum (C. parvum) the mainly pathogenic specie responsible for human infection (Xiao et al. 2001). The disease undertakes domestic and wild animal's species. Svobodova & Svoboda (2001) affirmed that Cryptosporidium is cited in a relevant way in the endoparasitosis, characterizing one of the 150 diseases with zoonótico potential described, demonstrating the great importance of zoonoses control and veterinary medicine collaboration to human medicine. Oshiro et al. (2000) observed that among 12 children with cryptosporidiosis 83,3% had contact with domestic animals (dog or cat) and all of them presented parasitism for C. parvum. The parasites endogenous development in the host culminates with the production of encysted forms, denominated oocysts, which ones are liberated with excrements. The oocyst stage is of great importance to dispersion, surviving and parasite infectivity, besides also being the important stage to detect the parasite and identify the species (Silva, 2004). According to Robertson et al. (2000), the frequency of Cryptosporidium infections is not much known and it is believed that most of the infected dogs are asymptomatic carriers. The clinic map of dog's gastroenteritis, although with less frequency, generally is associated to stress conditions and immunosuppression. Figueiredo et al. (2004) affirm that the frequency of dog's cryptosporidiosis is difficult to be determined once the most infected dogs are asymptomatic carriers. The main purpose of this paper is to determine the Cryptosporidium spp occurrence in dogs belonging to kennels in the urban area of Uberlandia, MG, Brazil.

Materials and Methods

It has been collected 91 excrement samples from different dogs, in kennels localized in the Uberlandia urban area, both sexes, with breed and ages varying. The simple casual sample technique for qualitative variable was adopted, composed to elements taken randomly from the population (Bussab & Morettin, 2002). The excrement samples were collected between eight and ten o'clock in the morning, using movable cage to facilitate animal identification that defecated and the immediately collection. To stimulate the defecation also has been used the animal's movimentation as technique and management. The collected excrements, approximately 10 gr per animal, were stored in polyethylene bottles with 20ml capacity, which ones were due walled in and identified. Lately, it has been added to each sample a 10% formalin solution in enough quantity to cover the excrements, aiming at conservation of biological material till the moment of examination. The samples were designated to the Parasitology Laboratory from the Biomedic Science Institute from the Federal University of Uberlandia. In order to have the exams done, it has been confectioned an excrements rubbing lamina per animal, which ones were colored using the modified Ziehl-Neelsen method, by Henriksen & Pohlenz (1981). The lamina analyzing was in optical microscopy, under 100 x objectives. They were considered positive those which presented oocysts which weigh was inside micrometric ocular in 4 to 6 m diameters (Rigo & Franco, 2002), having spherical forms, colored purple to pink lighted, with the presence of dark granulations inside it contrasting to the green color on the background. It has been realized sweeping in all the lamina extension searching for Cryptosporidium spp oocysts, and when similar structures were detected such as shape and color the micrometric ocular was used to measurement as a differential method. The experiment was executed following the rules from the institution ethic committee.

Results

In all the analyzed samples none of them were found positive.

Discussion and Conclusions

All the 91 analyzed samples were negative to the search to the oocyst, resembling studies realized by Gorman et al. (1989) and Chattopadhyay et al. (2000), which affirmed that the Cryptosporidium prevalence in dogs is 0%. Fayer (1997) analyzed 50, 101 and 200 adult dog's excrement samples in Finland, Scotland and in Edinburgh, in German, and didn't find positive samples in dogs of different ages. The observed results disagree to the results found by León et al. (1994), Svobodova et al. (1995), Causas et al. (1996), Navarro et al. (1997), El-Hohary & Abdel-Latif (1998), Kim et al. (1998), Gennari et al. (1999), Sawano et al. (2002), Figueiredo et al. (2004), Kumar et al. (2004), which found the respective occurrences: 12,38%; 4.6%; 7,4%; 2,26%; 8,33%; 9,7%; 2,83%; 9,3%; 1,85%; 8,53%. This, possibly, can be related to the kennel's sanitary conditions involved, animal's age and the used number of samples. Mundim et al. (2001), determined the occurrence of Cryptosporidium parvum, in Uberlandia city, MG, finding an 1,90% percentual, confirming, therefore, the decreased parasite occurrence evaluated in the same region of the present study. Lallo & Bondan (2006) compared the modified Ziehl-Neelsen method and PCR, and observed a prevalence of 8,8% and 9,5%, respectively, demonstrating that the PCR technique permitted a greater detection in front of light microscopy, seeing that young animals presented lower frequency related to adult animals, without significant difference between sexes. Inside the analyzed samples, none of them were identified as positive, characterizing the non occurrence of the parasite in the evaluated animals of the kennels in the urban area of Uberlandia, MG, Brazil.

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