Caracterização epidemiológica e fatores de risco associados à leptospirose em ovinos deslanados do semiárido brasileiro

Systematic review and meta-analysis on seroprevalence of leptospirosis in non-human primates worldwide

Leptospirosis is a zoonotic disease whose transmission is linked to multiple factors involving the interface between animals, humans, and the environment. This disease is of great importance for public health, as it profoundly affects the health aspects of the population and animals. Considering the importance of non-human primates in this epidemiological chain, the objective of this research was to conduct a systematic literature review with meta-analysis, providing information on leptospirosis in non-human primates (NHPs) and an update on the infection situation in Brazil and other countries. Thus, a search was performed in five databases, initially finding 3332 studies, of which 32 met the eligibility criteria and were used for the systematic review. According to them, the most prevalent serogroup in non-human primates was Icterohaemorrhagiae, which is adapted to rodents as primary hosts. A wide distribution of the infection was found in the regions of both wild and captive animals. Through meta-analysis, the seroprevalence rate of leptospirosis in non-human primates was 27.21% (CI 17.97-38.95%). Cochran's Q test (p < 0.01) identified heterogeneity between studies, classified as high by the Higgins and Thompson test (I2 = 92.4%). Therefore, seroepidemiological and Leptospira isolation studies in non-human primates are important to investigate and monitor the suspected impact of these species as maintainers or transmitters of the pathogen to humans and other wild and domestic animals, in addition to demonstrating the need for standardization related to control and prevention measures.

Detection of Leptospira spp. in genitourinary tract of female goats managed in the brazilian semiarid

Studies related to the prevalence of leptospirosis in the semiarid region showed that even during long periods of drought, the disease has a remarkable frequency in herds in the region. It is a neglected disease and the extent of its effects in the Brazilian semiarid region is not known. The dynamics of this agent is well studied in the urinary tract, however, there are not many studies regarding the genital tract in female goats. Observing this scenario, the present work aimed to diagnose Leptospira spp. in female goats kept in the Brazilian semiarid region by means of serological, molecular and isolation techniques. Blood samples, vaginal fluid, urine and fragments of organs from the genitourinary tract were collected from 40 goats destined for slaughter. Microscopic agglutination test (MAT) was used as a serological technique, with a battery of 24 serovars. The Polymerase Chain Reaction (PCR) of the vaginal fluid, urine and organ fragments was performed, as well as the bacterial growth of these same products in a selective medium. Isolation positive samples were subjected to PCR. It was observed that two (5%) animals were serologically positive for the Pyrogenes serogroup. A total of 29 (72.5%) animals were PCR positive, with DNA present in 51/160 (31.8%) samples from the genital tract and 34/120 (28.3%) from the urinary tract, with no statistical difference. For bacterial growth, 22/40 (55%) animals were positive for growth, with morphology being observed in 19/160 (11.8%) for the genital tract and 16/120 (13.3%) for the urinary tract, with no statistical difference. Two uterus samples showed 99% similarity with L. interrogans after sequencing. Thus, female goats kept under semiarid conditions were positive for Leptospira spp, with positive samples from both the urinary and genital tracts, which possible is an alternative way of adapting and maintaining the agent for severe and adverse conditions.

Cross-sectional survey for sheep leptospirosis in the northeast region of Brazil

Sheep farming has shown expressive growth, even in the Northeast region of Brazil, with rainfall below expectations in the last decade. This growth has been observed not only in the number of herds, but also in the number of properties involved in sheep farming. Although expressive, the production of small ruminants still presents low levels of performance, mainly due to the occurrence of diseases, which constitute an obstacle to this activity. The aim of this study was to determine the factors associated with the seroprevalence of leptospirosis in sheep in Northeastern Brazil. Blood samples were collected from 3438 sheep in 190 herds from 48 municipalities, belonging to the states of Ceará, Paraíba, Piauí, Rio Grande do Norte and Sergipe. Serological diagnosis was performed using the microscopic agglutination test (MAT). In 76.3 % (95 % CI = 69.79-81.81) of the herds there was at least one animal seropositive for at least one of the Leptospira spp. serogroups and 14.94 % (95 %CI = 13.8-16.18) of the animals were seropositive. The state of Paraíba had the highest herd (95.7 %) and animal (26.6 %) prevalences, followed by Ceará (93.9 % and 23.7 %, respectively). The most frequent serogroups were Autumnalis (18.68 %), Australis (17.9 %) and Pyrogenes (15.18 %). There was no association between the studied variables and the herd-level prevalence of leptospirosis. High herd and animal-level seroprevalences was found for sheep leptospirosis in the semiarid region of Northeastern Brazil, and there is a need to implement control and prevention measures, such as quarantine, serology, vaccination and adequate treatment, in addition to the introduction of proven healthy animals, mainly in the states of Paraíba and Ceará, aiming to reduce the prevalence of disease.

Use of serological and molecular techniques for detection of Leptospira sp. carrier sheep under semiarid conditions and the importance of genital transmission route

It is possible that there are peculiarities in the epidemiology of leptospirosis in regions with a semiarid climate, where the environment is often adverse, allowing the occurrence of alternative transmission routes. The objective of the work was to generate contributions to the diagnosis and epidemiology of Leptospira sp. infection in sheep reared in semiarid conditions, using serological, molecular and microbiological techniques for diagnosis in dry and rainy seasons. Samples of blood, vaginal fluid, urine, bladder, kidney, uterus, uterine tube, ovary and placenta were collected from 104 sheep (52 animals per season - dry and rainy) slaughtered in the Brazilian semiarid. Diagnostic tests performed were microscopic agglutination test (MAT), polymerase chain reaction (PCR) and bacterial isolation. Anti-Leptospira sp. antibodies were found in 26 (25%) of the animals analyzed by MAT at 1:50 dilution (cut-off 50), while 69 (66.3%) animals had at least one organ/fluid with the presence of Leptospira sp. DNA. Overall, PCR was performed on 758 fragments of organs/fluids from the genital and urinary tracts, and 519 (68.5%) samples tested positive. PCR-positivity was statistically different in dry (46.2%) and rainy (11.5%) seasons for vaginal fluid. It was possible to perform the DNA sequencing in nine samples with 99% similarity to L. interrogans and recovery of viable strains in three samples of vaginal fluid. Regardless of the biological material used in PCR to detect carrier animals and the season, the highest MAT sensitivity values were obtained with cut-off 50 compared to 100. The results obtained indicate that, even in the adverse environmental conditions of the semiarid region, leptospires may survive and propagate by alternative routes of transmission, such as sexual, and the presence of PCR-positive genital tracts in ewes suggests that sexual transmission may play an important role in the epidemiology of the disease in sheep in Brazilian semiarid. In addition, it is suggested the use of titer 50 as cut-off point at serology in semiarid conditions.

Influence of breed on the clinical and hemato-biochemical parameters in sheep experimentally infected with Leptospira sp

Early diagnosis of leptospirosis may aid in a favorable prognosis in infected animals, but there are few reports of clinical and hematochemical changes in the ovine species, nor whether the breed exerts any influence on the response to infection. Thus, the objective of the present study was to evaluate the clinical, biochemical and hematological alterations in Santa Inês and crossbred ewes challenged with Leptospira interrogans serogroup Pomona serovar Kennewicki. Twenty-four sheep were used in this experiment, 12 crossbred (group A) and 12 Santa Inês (group B). In each group, sheep were conjunctivally and intraperitoneally challenged. During 60 days post-infection the ewes were evaluated for the presentation of clinical signs and the blood was collected for hemogram and serum biochemistry. Concentration of urea and creatinine; serum aspartate aminotransferase activity (AST); gamma-glutamyltransferase (GGT); total protein and albumin; total bilirubin, direct and indirect were analyzed. The urine of these sheep was collected for urinalysis. Only two Santa Inês sheep showed blood in the urine. Clinical signs implicated in Leptospira sp. infection were not identified. Some sheep had anemia, especially crossbred. However, anemia may be attributed to the more effective cellular response that has been identified in crossbred animals. Only one animal presented leukocytosis with neutrophilia, while 11 presented atypical leukopenia, especially those of the Santa Inês breed. There was a decrease in total protein and albumin, as well as the increase in gammaglutamyltranspeptidase (GGT), especially in Santa Inês sheep. The level of aspartate aminotransferase (AST) remained within the normal range for the species. A significant increase (p < 0.05) in conjugated bilirubin levels in challenged animals was detected. Only one sheep intraperitoneally challenged presented a high level of urea in the blood, but the creatinine level remained within the normal range. The intraperitoneal route was responsible for more significant changes (p < 0.05) in the hemogram and biochemistry when compared to the conjunctival route. The results indicate that crossbred sheep have a more efficient cellular response than Santa Inês sheep, which may confer a greater resistance to infection. Clinical signs are not good parameters to follow the development of leptospirosis in crossbred and Santa Inês breed. Hematological and biochemical analyzes were useful in the detection of anemia and possible liver changes caused by leptospirosis. The intraperitoneal route was able to cause more conclusive alterations of the analyzed parameters, however, it is possible that the alterations caused by the conjunctival route reproduce in a more faithful way what happens in a natural situation of infection.

Epidemiologic analysis of Leptospira spp. infection among sheep in Pernambuco state, Brazil

ABSTRACT: This study aimed to analyze epidemiological aspects and spatial characteristics of Lesptospira spp. infection among sheep in Pernambuco state, Brazil. A total of 426 samples were collected from unvaccinated animals aged 1 year or older, and submitted to Microscopic Agglutination Test (MAT). To study the risk factors, a standardized investigative survey of sheep farmers, with objective questions, was conducted to establish the general characteristics of the farm property production, reproductive management, and health plan. From 426 samples analyzed, 83 (19.5%; CI 15.9 - 23.6%) were positive; among them, the most prevalent serovar was Autumnalis (32.4%). Significant differences were observed between gender (OR = 0.38; CI 0.14 - 0.99), production system (OR = 2.03; CI 1.07 - 3.84), types of herd (OR = 2.28; CI 1.39 - 3.72), absence of rodents to the grain storage (OR = 0.55; CI 0.34 - 0.91), and restriction to surface waters (OR = 0.60; CI 0.37 - 0.99). Leptospira spp. infection is disseminated in sheep herds, and multiple factors can influence its occurrence. Health education programs and worker training in prevention and control of leptospirosis and other infectious diseases may be useful to reduce infection rates and economic losses caused by this disease.

Animal leptospirosis in Latin America and the Caribbean countries: reported outbreaks and literature review (2002-2014)

Leptospirosis is a worldwide zoonotic disease whose transmission is linked through multiple factors in the animal-human-ecosystem interface. The data on leptospirosis reported to the World Organization for Animal Health (OIE) for Latin America and Caribbean (LAC) countries/sovereign territories from 2005-2011 were mapped, showing a wide distribution of outbreaks in the region. Tropical terrestrial biomes are the predominate ecosystems showing reports of outbreaks. Climatic and ecological factors were relevant to the occurrence of epidemic outbreaks. The available scientific information from 2002-2014 was summarized to obtain a general overview and identify key issues related to the One Health approach. The primary serological test used for diagnosis and for conducting surveys was the microscopic agglutination test (MAT). Reports regarding the isolation and typing of leptospires were scattered and limited to data from a few countries, but their results revealed considerable biodiversity at the species and serovar levels. A total of six out of 11 currently named pathogenic species were found in the region. There was also high diversity of animal species showing evidence of infection by leptospires, including rodents, pets, livestock and wild animals. Prevention and control measures for leptospirosis should consider issues of animal and human health in the context of ecosystems, the territorial land borders of countries and trade.

Leptospirose em pequenos ruminantes: situação epidemiológica atual no Brasil

A leptospirose em pequenos ruminantes é uma doença que pode causar perdas econômicas devido à ocorrência de abortamentos, natimortalidade e diminuição da produção de leite. A infecção pode se apresentar nas formas aguda, crônica e inaparente. Na forma aguda, pode ocorrer anorexia, depressão, dificuldade respiratória, febre, hemoglobinemia e hemoglobinúria. Na forma crônica, abortamentos e natimortalidade são comuns. Vários inquéritos sorológicos recentes conduzidos no Brasil apontaram frequências de soropositividade variando de 3,4 a 31,3% em caprinos, e de 0,7 a 34,6% em ovinos. Os sorovares reatores mais frequentes foram Autumnalis, Grippotyphosa, Hardjo, Icterohaemorrhagiae e Pyrogenes. O teste de soroaglutinação microscópica é o método mais empregado para o diagnóstico da infecção. O controle da leptospirose em pequenos ruminantes é baseado na identificação de fontes de infecção, controle de roedores, controle da aquisição de animais e imunização sistemática com vacinas inativadas que contenham sorovares de leptospiras regionais.

Leptospirosis seroprevalence and risk factors for sheep in Maranhão state, Brazil

This study was conducted to determine leptospirosis seroprevalence in sheep and their spatial distribution as well as identify risk factors associated with seropositivity in sheep from 37 herds and 11 municipalities in the Presidente Dutra microregion, Maranhão state, Brazil. We analyzed 379 blood serum samples using a Microscopic Agglutination Test (MAT). The individual seroprevalence was 32%. Of the 37 herds studied, 30 (81%, 95% CI 69-94%) had at least one seropositive animal. In seven municipalities, we observed infection in 100% of the herds. The serovars recorded were Grippotyphosa (67%), Wollfi with Hardjo (9%), Bratislava (9%), Hardjo (5%), Icterohaemorrhagiae (5%), Pomona (2%), Castellonis (2%) and Copenhageni (0.8%). We concluded that the Leptospira spp. in sheep is widespread in the area of sheep farms in Maranhão state, and a risk factor is the animals' water source.