Diagnosis of Leptospira spp. Infection in Sheep Flocks in the State of Mato Grosso, Brazil
Keywords:small ruminants, leptospirosis, serology.
Background: Leptospirosis has a worldwide distribution with high social and economic impact. It is caused by a variety of Leptospira spp. serovars, particularly in tropical regions. Various species of animals can be affected by Leptospira spp. including cattle, horses, sheep, goats and swine, and can act as a reservoir for human infection. In Brazil, sheep leptospirosis has been diagnosed in a variety of States, however, little is known about sheep flocks of Mato Grosso. Considering the marked growth of sheep industry in Mato Grosso State in past recent years, this study aimed to evaluate the frequency of serologically positive sheep for Leptospira spp. serovars in the State of Mato Grosso (Brazil).
Materials, Methods & Results: Blood samples of 346 sheep, which belonged to 16 sheep flocks of the medium northern region of Mato Grosso was obtained by jugular vein puncture. Serum was obtained by blood centrifugation and stored at -20°C until the test to be performed. The diagnosis was performed using the microscopic agglutination test. Serovars Australis, Autumnalis, Bataviae, Bolívia, Castelonis, Celledoni, Grippotyphosa, Hardjo, Hardjobovis, Hebdomadis, Icterohaemorrhagiae, Javanica, Lagoa, Norma, Panama, Pomona, Sejroe, Shermani, Szwajizak, and Wolffi were tested. Reactions were considered positive with minimum titration of 1:100. Considering all serovars, 54.9% of sheep were positive, and the serovar more frequently detected was Celledoni (22.8%), followed by Javanica (19.4%), Castellonis (16.5%), and Norma (15.3%), with predominance of titration of 100 for these serovars, while only one sheep had a titration of 1:800 detected for serovar Hardjo. All flocks (100%) were positive (at least one positive animal), with the frequency of animals positive to Leptospira spp. varying of 31.3% to 79.2% in flocks.
Discussion: Infection for Leptospira spp. in humans has a large social and sanitary impact. Under an animal health perspective, beyond sanitary impact, leptospirosis have a large economic impact and can act as important reservoirs for Leptospira spp. for human infection, especially in tropical conditions, which favor the persistence of agent in the environment. The occurrence of sheep leptospirosis has been diagnosed in several States of Brazil as Rio Grande do Sul, Paraíba, Rio de Janeiro, São Paulo and Maranhão, with frequency of herds positive for Leptospira spp. varying of 5.4% to 47.4%, however, the frequency of positive sheep in this study was higher than these previous reports in other Brazilian States. The most frequent serovar in sheep flocks have a great importance for prophylactic control. However, there were identified as main frequent serovar Celledoni and Javanica, which are considered unusual in sheep, and indicates a peculiar profile of ovine serovars for the region. Considering de high frequency of positive farms (100%) in Mato Grosso and the lack of studies about the occurrence of leptospirosis in this region, our results suggest the occurrence of risk factors that can favor the dispersion and survival of agent. Contact of the sheep evaluated in this study with other animal species such as cattle, dogs, and horses that can serve as a source for sheep infection or may become contaminated from sheep. Then, the profile of sheep infection by Leptospira spp. in the State of Mato Grosso has a peculiar profile of serovars, with high frequency of infection of animals and herds.
Alves C.J., Alcindo J.F., Farias A.E., Higino S.S.S., Santos F.A., Azevedo S.S., Costa D.F. & Santos C.S.A.B. 2012. Caracterização epidemiológica e fatores de risco associados à leptospirose em ovinos deslanados do semiárido brasileiro. Pesquisa Veterinária Brasileira. 32(6): 523-528.
Barbante P., Shimabukuro F.H., Langoni H., Richini-Pereira V.B. & Lucheis S.B. 2014. Leptospira spp. infection in sheep herds in southeast Brazil. Journal of Venomous Animals and Toxins including Tropical Diseases. 20(1): 20.
Carvalho S.M., Mineiro A.L., Castro V., Genovez M.E., Azevedo S.S. & Costa F.A.L. 2014. Leptospirosis seroprevalence and risk factors for sheep in Maranhão State, Brazil. Tropical Animal Health and Production. 46(2): 491-494.
Hermuche P.M., Maranhão R.L.A., Guimarães R.F., Carvalho Júnior O.A., Gomes R.A.T., Paiva S.R. & McManus C. 2013. Dynamics of sheep production in Brazil. ISPRS International Journal of Geo-Information. 2(3): 665-679.
Herrmann G.P., Lage A.P., Moreira E.C., Haddad J.P.A., Resende J.R., Rodrigues R.O. & Leite R.C. 2004. Soroprevalência de aglutininas anti-Leptospira spp. em ovinos nas Mesorregiões Sudeste e Sudoeste do Estado Rio Grande do Sul, Brasil. Ciência Rural. 34(2): 443-448.
Higino S.S.S. & Azevedo S.S. 2014. Leptospirose em pequenos ruminantes: situação epidemiológica atual no Brasil. Arquivos do Instituto Biológico. 81(1): 86-94.
Instituto Brasileiro de Geografia e Estatística (IBGE). 2013. Pesquisa pecuária Municipal. Available at . [Accessed online in August 2016].
Levett P.N. 2001. Leptospirosis. Clinical Microbiology Reviews. 14(2): 296-326.
Martins G., Penna B., Hamond C., Leite R.C., Silva A., Ferreira A., Brandão F., Oliveira F. & Lilembaum W. 2012. Leptospirosis as the most frequent infectious disease impairing productivity in small ruminants in Rio de Janeiro, Brazil. Tropical Animal Health and Production. 44(4): 773-777.
Martins G. & Lilenbaum W. 2013. The panorama of animal leptospirosis in Rio de Janeiro, Brazil, regarding the seroepidemiology of the infection in tropical regions. BMC Veterinary Research. 9(1): 237.
Petrakovsky J., Bianchi A., Fisun H., Nájera-Aguilar P. & Pereira M.M. 2014. Animal Leptospirosis in Latin America and the Caribbean countries: Reported outbreaks and literature review (2002-2014). International Journal of Environmental Research and Public Health. 11(10): 10770-10789.
How to Cite
This journal provides open access to all of its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Such access is associated with increased readership and increased citation of an author's work. For more information on this approach, see the Public Knowledge Project and Directory of Open Access Journals.
We define open access journals as journals that use a funding model that does not charge readers or their institutions for access. From the BOAI definition of "open access" we take the right of users to "read, download, copy, distribute, print, search, or link to the full texts of these articles" as mandatory for a journal to be included in the directory.
La Red y Portal Iberoamericano de Revistas Científicas de Veterinaria de Libre Acceso reúne a las principales publicaciones científicas editadas en España, Portugal, Latino América y otros países del ámbito latino