Prevalence and geographical distribution of bovine cysticercosis in the mesoregion of Northern Minas Gerais

ABSTRACT The knowledge of the prevalence of bovine cysticercosis is important for the implementation of control programs. The objective was to evaluate the prevalence and geographical distribution of bovine cysticercosis in Northern Minas Gerais. For that, 14,556 cattle were evaluated during the federal post-mortem inspection in 27 municipalities of five microregions: Janaúba, Montes Claros, Januária, Pirapora and Bocaiúva. The prevalence of Cysticercus bovis was 1.03% with distribution in all microregions evaluated of the northern Minas Gerais. All municipalities with a sampling number of cattle slaughtered above 543 showed positive animals for cysticercosis. The microregions of Bocaiúva, Montes Claros, Janaúba, Januária and Pirapora presented a prevalence of cysticercosis at 2.11%, 1.17%, 1.01%, 0.90% and 0.56%, respectively. The microregions of Montes Claros and Januária presented a greater chance of finding positive cattle for cysticercosis. As there are positive cases of cysticercosis in all microregions evaluated, there is a risk to human health.


INTRODUCTION
The bovine taeniasis-cysticercosis complex can be defined as a set of pathological alterations caused by the adult and larval forms of Taenia saginata. This zoonosis can be expressed in two distinct forms, taeniasis, which affects human, or cysticercosis, caused by the presence of Cysticercus bovis in bovine tissues (Magalhães et al., 2017). Infection of humans with T. saginata is common in areas of the world where sanitation is inadequate (Usip et al., 2011;Acevedo Nieto et al., 2012). The parasite is commonly found in South America, North America and Africa (Usip et al., 2011), mainly in areas marginalized by public power. The knowledge of the prevalence of bovine cysticercosis is important for the implementation of control programs (Acevedo Nieto et al., 2012). Anatomopathological diagnosis is the most important instrument in veterinary medicine, since the identification of cysticercosis at the time of animal slaughter is essential for the success of human taeniasis prevention programs (Côrtes, 2000).
Besides the damages imposed on human health, the economic aspect includes direct and indirect losses due to the disease in the animals. The carcasses or organs parasitized with cysticercus can have different destinations, depending on the degree of involvement, which causes economic losses to the beef supply chain (Laranjo-González et al., 2016) and, currently, synonymous with technical inadequacy in relation to the adoption of Good Production Practices (Rossi et al., 2014). In view of the above, the goal was to evaluate the prevalence and geographical distribution of bovine cysticercosis in the northern region of the State of Minas Gerais.

MATERIAL AND METHODS
This cross-sectional study analyzed data from the slaughter of cattle from January to December 2010. Males and females aged between 20 and 60 months were slaughtered in a slaughterhouse with federal inspection, located in Janaúba, State of Minas Gerais, Brazil.

DISCUSSION
As the majority of municipalities presented positive cases of cysticercosis, the sanitary conditions of cattle rearing properties should be improved, since they are related to the prevalence of the disease (Acevedo Nieto et al., 2012). As there have been cases of positive animals in all the municipalities of higher representativeness (> 543 animals per municipality), the problem is even more serious. São Francisco and Janaúba presented higher prevalence among the municipalities of higher representativeness. The apparent prevalence recorded in this study, in general, is not considered endemic because, for the Pan American Health Organization, an endemic area has a prevalence above 5%. Although the prevalence of cysticercosis in the municipality of Claro dos Poções is high, it cannot be considered endemic due to the small sample size. Magalhães et al. (2017), in the municipality of Salinas, State of Minas Gerais, reported a prevalence of 4.7% of bovine cysticercosis. The prevalence of bovine cysticercosis is higher in regions where the population has low socioeconomic status (Queiroz et al., 2000). It is noted that, with the exception of Montes Claros, the municipalities evaluated in this study have an average HDI (Human Development Index), below the Brazilian average, and therefore, more serious health problems. Taking into account factors related to health and development, this mesoregion is also below the average of the State of Minas Gerais. For Pinto et al. (2019), the predominance of a low family income in the researched communities, accompanied by the respective implications of sanitary deficiency and low standard of knowledge, are indicative signs of the common occurrence of the disease. The risk to humans in these microregions of Minas Gerais may be underestimated, as there are frequent cases of clandestine slaughter. Most of these municipalities do not have a slaughterhouse, which strengthens the previous assertion. Ferreira et al. (2014) reported that the lack of official inspection establishments may cause underreporting. In view of the above, municipalities that did not present positive cattle can be within this description, which suggests risk to humans. Garro et al. (2015) reinforced the need to implement hygienic-sanitary and technological control in beef cattle production in São João Evangelista, State of Minas Gerais, since the consumption of raw uninspected meat was considered the main risk factor for the occurrence and maintenance of the bovine taeniasis-cysticercosis complex.

CONCLUSION
There are cases of bovine cysticercosis in the Northern region of the State of Minas Gerais, distributed in all microregions evaluated. For this reason, there is a risk to human health in this macroregion.