Subsistence swine farming: seroprevalence and risk factors associated with Lawsonia intracellularis infection in the state of Minas Gerais Brazil in 2016.

Although it is considered an economically relevant and prevalent disease, little information is available on the epidemiology and risk factors of porcine proliferative enteropathy (PPE) in commercial pigs, and no publication is available on subsistence pig farming. The objectives of this study were to estimate the seroprevalence of L. intracellularis and identify associated risk factors in backyard pigs in the 12 mesoregions of the state of Minas Gerais, Brazil. Blood from pigs between 2 months and 6 years of age were sampled; an epidemiological questionnaire was applied to 288 properties investigated in 2016. Serum samples were tested for the presence of anti-L. intracellularis antibodies using an immunoperoxidase monolayer assay. The seroprevalence of L. intracellularis was 97.7% (CI 95%: 96.7-98.4), and there was no statistical difference among the prevalence of the sampled mesoregions. Only 3 of the 12 risk factors were significant when samples were analyzed from strongly seropositive animals (≥ 1:120) in a Poisson multivariate regression model. There was an interaction between properties in peri-urban areas and extensive production systems. This interaction demonstrated an increase in prevalence rates by 3.7 times (95%CI: 2.4-5.8). Properties close to dumps demonstrated an increase in prevalence rates by 2.2 times (95%CI: 0.99-4.8). In conclusion, anti-L. intracellularis antibodies were widely dispersed in subsistence pig farming's in Minas Gerais, indicating a wide circulation of the agent in this type of production system. The interactions of animals raised close to peri-urban areas, extensively, and close to landfills are risk factors for spread of PPE.

Trânsito de suídeos em Minas Gerais, Brasil / Swine industry animal network in Minas Gerais, Brazil

Minas Gerais ocupa a quarta posição entre os estados brasileiros com maior produção de suídeos. A suinocultura envolve intenso trânsito de animal e, consequentemente, forma complexas redes de fluxo. Com a movimentação, esses animais podem carrear agentes patogênicos que podem ser disseminados por meio dessa rede de contatos. Diante disso, este estudo tem como objetivo descrever e analisar o trânsito de suídeos em Minas Gerais para compreender os caminhos mais prováveis para a disseminação de possíveis surtos. Os dados foram fornecidos pelo Instituto Mineiro de Agropecuária, originados das 56.823 Guias de Trânsito Animal emitidas no ano de 2009. A movimentação dos 5.354.735 suídeos foi analisada segundo a sua finalidade. O trânsito mais intenso ocorreu com a finalidade de abate (79,95%), seguida pelas finalidades de engorda (10,64%) e de reprodução (9,38%). A movimentação de animais para exposições e leilões representou apenas 0.03% dos transportes realizados. O trânsito em Minas Gerais é heterogêneo e concentra-se, principalmente, nas regiões do Triângulo Mineiro, Alto Paranaíba e Zona da Mata. As características do fluxo de animais tornam a utilização da estratégia das redes ideal para a elaboração das medidas de vigilância e controle das doenças dos suídeos em Minas Gerais.

Minas Gerais is the fourth largest Brazilian state in swine production. This activity involves the intense animal movement producing a complex network. In this context animals can carry on infectious agents and transmit them among the population. The aim of this study is to describe and analyze the movement of swine in Minas Gerais and to understand the most likely paths to spread possible outbreaks. Data were provided by the Instituto Mineiro de Agropecuária, derived from 56.823 Transit Animal Guides issued in 2009. The movement of 5.354.735 swine was analyzed according to its purpose. The traffic was more intense for slaughter (79.95%) followed by finishing (10.64%) and reproduction purposes (9.38%). The fairs and auction purposes represented only 0.03%. Movement of animals in Minas Gerais is heterogeneous and is mainly concentrated in same regions such as Alto Paranaíba and Zona da Mata. It also occurs in the Central and South regions. The network approach, based on graph theory, can be used more efficiently for the development of swine disease control programs and crisis management in Minas Gerais.