Leptospirosis and brucellosis seroepidemiology in sheep and dogs from non-mechanized rural properties in the northwestern region in the state of Paraná

Abstract

Sheep breeding has been important in agribusiness, transforming the Brazilian productive scenario. However, it is still deficient due to the damages caused by infectious diseases. Leptospirosis is a severe disease with global distribution, caused by bacteria from the Leptospira genre affecting both humans and animals. The general infection is unapparent, or its clinical signs, when present, are similar to other infections. Brucellosis is an infectious disease caused by bacteria from the Brucella genre responsible for reproductive disorders in animals, especially ruminants. The purpose of this paper was to seroepidemiological study of Leptospira spp. and Brucella ovis in sheep and dogs from nonmechanized rural properties from the northwestern region in the state of Paraná, Brazil. In order to detect anti-Leptospira antibodies, microscopic agglutination (MAT) was performed. For anti-Brucella antibodies, the agar gel immunodiffusion assay (AGID) was performed. From the total 542 samples from sheep sera analyzed, 11.25% were considered reagent to Leptospira spp. and 18.26% to Brucella ovis. From the 36 dog samples, 25% were reagent to MAT and AGID. From the 32 properties analyzed, 75% were considered positive for leptospirosis and 56.25% for brucellosis. Antibodies against the most probable serovars were Hardjo (34.42%) and Butembo (44.44%) in sheep and dogs, respectively, and the variable exchange of animals among properties was associated to leptospiric infection (p=0.028) in sheep. Leptospirosis and brucellosis are present in the sheep herd and dogs in the rural properties studied, and such result is a warning of the zoonotic importance and the need to establish sanitary programs directed to these animal species. ResumoA ovinocultura tem se destacado no agronegócio, transformando o cenário produtivo do Brasil, porém ainda possui uma deficiência devido aos danos causados por doenças infecciosas. A leptospirose é uma doença grave de distribuição mundial causada por bactérias do gênero Leptospira que afeta o homem e os animais. A infecção geralmente é inapetente, ou os sinais clínicos, quando presentes, são similares aos de outras infecções. A brucelose é uma enfermidade infecciosa causada por bactérias do gênero Brucella responsáveis por desordens reprodutivas nos animais, especialmente nos ruminantes. O objetivo deste trabalho foi realizar um estudo soroepidemiológico de Leptospira spp. e Brucella ovis ovinos e cães de propriedades rurais não tecnificadas da região noroeste do estado do Paraná, Brasil. Para detecção de anticorpos anti-Leptospira foi realizada a soroaglutinação microscópica (SAM), e para anticorpos anti-Brucella, a prova de imunodifusão em gel de ágar (IDGA). Das 542 amostras de soro ovino analisadas, foram consideradas reagentes 11,25% para Leptospira spp. e 18,26% para Brucella ovis. Das 36 amostras de cães, 25% foram regentes a SAM e IDGA. Das 32 propriedades, 75% foram consideradas positivas para leptospirose e 56,25% para brucelose. Os anticorpos contra os sorovares mais prováveis for...

First study of Brucella ovis antibodies in purebred sheep flocks in the State of Parana, Brazil

“…In Brazil, the flock seroprevalence of B. ovis in the studied populations was between 0% (Marinho and Mathias, 1996;Chiebao, 2011) and 34% (Silva et al, 2003). Our study seroprevalence estimate, based on serologic testing, is much lower than other prevalence estimates published in Brazil with commercial non-mechanized sheep flocks (Magalhães Neto and Gil-Turnes, 1996;Schafer et al, 1997;Coleto et al, 2003;Pinheiro Junior et al, 2009;Rizzo et al, 2009;Silva et al, 2009;Alves et al, 2010;Souza et al, 2012;Araujo et al, 2013;Martins et al, 2013;Azevedo et al, 2014;Rizzo et al, 2014;Manhezzo et al, 2015;Lima et al, 2020;Teixeira et al, 2021), including 1.40% (Cunha Filho et al, 2007) and 18.26% of AGID seropositive sheep (Oliveira et al, 2016) (Magalhães Neto and Gil-Turnes, 1996), and 2.89% (Machado et al, 2015) in Rio Grande do Sul, but both studies analyzed intensive half-bred herds, not purebred animals, maybe justifying the higher occurrence when compared to this study, as more intensive systems can contribute to the introduction and persistence of B. ovis infection in sheep flocks (Elderbrook et al, 2019) and rams from large flocks were 14 times more likely to become infected than rams from small flocks (Chávez et al, 2013). It is also important to stress that molecular characterization showed a high genetic diversity among B. ovis field isolates from Rio Grande do Sul State, Brazil (Dorneles et al, 2014), reinforcing the importance of studies on B. ovis survey.…”

“…Serological tests for antibodies detection are the most useful epidemiological tool for diagnosis of Brucella infection around the world (Erdenebaatar et al, 2004). In Brazil, the Ministry of Agriculture, Livestock and Food Supply (MAPA) recommends Agarose Gel Immunodiffusion (AGID) as the standard test (Brazil, 2004), and it has been already used to identify seropositive sheep in the Parana State (Cunha Filho et al, 2007;Oliveira et al, 2016), but never in purebred sheep flocks.…”

“…Although the infection by B. ovis has already been identified in several Brazilian states using AGID as a serological diagnostic method, and it is included in the National Program for the Sanity of Goats and Sheep of Ministry of Agriculture, Livestock and Food Supply (MAPA) (Brazil, 2004), studies have demonstrated the occurrence of B. ovis antibodies only in commercial sheep herds from non-mechanized farms in Brazil through AGID test (Marinho and Mathias, 1996;Chiebao, 2011), there are even a few from Parana State (Cunha Filho et al, 2007;Oliveira et al, 2016), and most of all, there are no studies with data from purebred sheep herds that sell animals with genealogical records to properties all over the country with breeding purposes, which is of great importance since B. ovis is sexually transmitted (Hartley et al,1955;Buddle, 1955;Blasco, 2010) and the infection may have silent dissemination in the flocks (Van Metre et al, 2012). Thus, this is the first serological study that aimed to determine the occurrence of antibodies anti-B.…”

Molecular and Serological Characterization of Pathogenic Leptospira Spp. Isolated From Symptomatic Dogs in a Highly Endemic Area, Brazil

“…In Brazil, Autumnalis was identi ed as the main infecting serogroup found in stray and asymptomatic dog populations from different parts of the country (47)(48)(49)(50)(51)(52)(53)(54)(55), however con rmation of infection by isolation and molecular/serological characterization hasn't been described yet. Unfortunately, isolation was not achieved in samples taken from dogs presenting the highest titers against Autumnalis in the present study, and the actual infecting serogroup attributed to those cases could not be determined.…”

Molecular and serological characterization of pathogenic Leptospira spp. isolated from symptomatic dogs in a highly endemic area, Brazil

“…In Brazil, Autumnalis was identified as the main infecting serogroup found in stray and asymptomatic dog populations from different parts of the country [ 42 – 45 ], however, confirmation of infection by isolation and molecular/serological characterization hasn’t been described yet. Unfortunately, isolation was not achieved in samples taken from dogs presenting the highest titers against Autumnalis in the present study, and the actual infecting serogroup attributed to those cases could not be determined.…”