The objective of this study was to determine the seroprevalence of leptospirosis and the predominant serogroups in serological tests of ruminants performed at the Transmissible Diseases Laboratory of the Federal University of Campina Grande, Patos, Paraíba, northeastern Brazil, between 2010 and 2017. This research included the records of serological tests for leptospirosis from 5594 animals, including 1527 cattle, 1761 goats, 2170 sheep, and 136 buffaloes from four Brazilian states (Paraíba, Pernambuco, Maranhão, and Rio Grande do Norte). Of the 5594 serum samples, 662 were serologically positive, corresponding to a frequency of 11.8%. Serjoe (30.6%), Autumnalis (13.6%), and Icterohaemorrhagiae (11.3%) were the most frequent subgroups among all species. The individual frequencies in cattle, goats, sheep, and buffaloes were 20% (306/1527), 8.3% (147/1761), 7.9% (171/2170), and 27.9% (38/136), respectively, with titers ranging from 1:100 to 1:3200. The most frequent serogroups according to animal species were as follows: Serjoe predominated in cattle (62%), followed by Icterohaemorrhagiae (12.5%) and Tarassovi (6.6%); Autumnalis was the most frequent in goats and sheep (29.4% and 26.9%, respectively), followed by Seramanga (12.5%) in goats and Icterohaemmorrhagiae (13.5%) in sheep; and Australis predominated in buffaloes (39.5%), followed by Pomona (31.6%) and Canicola (21.1%). Leptospira sp. infection, determined by serology, is widespread in ruminants (cattle, goats, sheep, and buffaloes) in northeastern Brazil, suggesting the existence of alternative transmission routes that are less dependent on environmental factors. Identification of the most frequent serogroups highlights the need to improve sanitary conditions, and implement efficient and targeted control measures directed at the primary infection sources.

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The aim of this survey was to determine epidemiological indicators for leptospirosis in equids from Paraíba state, Northeastern Brazil. A total of 138 equids were sampled from 58 rural properties, and for the diagnosis of leptospirosis it was used the Microscopic Agglutination Test (MAT) with 22 serovars as antigens. A seropositivity found was 40.6% (56/138). The reactive serogroups were Australis (43%), Sejroe (16.3%), Icterohaemorrhagiae (14.3%), Grippotyphosa (10.2%), Canicola (6.1%), Tarassovi (4.1%), Pomona (2%), Ballum (2%) and Hebdomadis (2%). Animals over 36 months of age presented higher chance of get seropositive (odds ratio = 3.04; 95% CI = 1.23 – 7.56; P = 0.016). The results obtained in the present work point to the high occurrence of seropositive equids for Leptospira sp. in the semiarid of Paraíba, Northeastern Brazil. As it is the first report of seropositive equidae in Paraíba, other surveys should be conducted in the region aiming to isolate and identify the agent for the determination of the current infection in the animals.

Considering the importance of leptospirosis in both equine husbandry and public health, as well as the relevance of knowledge of current serogroup and the small number of studies addressing this disease in equines in Northeastern Brazil, the present study performed a serological survey of Leptospira spp. in a serum bank of 1,267 equines originating from 177 municipalities, located in four states in Northeastern Brazil: Ceará, Rio Grande do Norte, Paraíba and Pernambuco. The microscopic agglutination test (MAT) was used for diagnosis of leptospirosis using 24 serovars as antigens. The frequency of reagent equines was 29.7% (376/1,267), and 68.9% (122/177) of municipalities had at least one positive reaction. The serogroups reagent were Australis (37.2%), Icterohaemorrhagiae (29.3%), Tarassovi (9.6%), Sejroe (5.8%), Pomona (5.3%), Grippotyphosa (4.5%), Pyrogenes (2.4%), Bataviae (1.9%), Ballum and Hebdomadis (1.3%), Mini (0.5%), Celledoni, Shermani, and Javanica (0.3% each). There were significant statistical differences regarding sex and age, with a higher frequency in females (P= 0.014), and in animals ≥ 6 years (P=0.001). We concluded that seropositivity to Leptospira spp. is high in equines in Northeastern Brazil, with a predominance of serologic reactions to the Australis serogroup in the border areas between the states, and the Icterohaemorrhagiae serogroup in coastal areas or their vicinity. The high degree of seropositivity found points to the need to implement prophylactic strategies, both intraspecies infection prophylaxis and rodent control. We also recommended avoiding animal crowding and separating animals according to sex and age group during handling.

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Donkeys (Equus asinus) are historically known for their close relationship to humanity, which raises the need to study zoonotic diseases that affect them. In this perspective, leptospirosis stands out as a disease with an economic and public health impact, and its occurrence is facilitated in times of higher rainfall indexes, especially in large urban centers. In view of the scarcity of information about leptospirosis in donkeys, the objective of this study was to detect the presence of Leptospira spp. and anti-leptospiral antibodies in donkeys rescued by a zoonosis center located in the Caatiga biome, Brazilian semiarid region. Overall, 30 donkeys of both sexes, aged between 4 months and 15 years, were used, from which 64 serum samples were collected and submitted to the microscopic agglutination test (MAT). In addition, 64 samples of urine, vaginal and preputial fluid, in duplicates, were subjected to the polymerase chain reaction (PCR) and microbiological. Sixteen (53.3%) animals tested positive in at least one diagnostic test, 12 (40%) of which were positive at MAT and seven (23.3%) in the molecular and bacteriological detection (urine, vaginal, and preputial fluid samples). This is the first report identifying donkeys infected with Leptospira spp. by molecular and bacteriological diagnosis in Brazil, and the first in the world to detect this agent in their genital fluids. The study also shows that donkeys are commonly exposed to leptospires in the Caatinga biome, and this constitutes a One Health-based concern, demonstrating the importance of broad studies where large numbers of humans and animals coexist when investigating zoonotic infections and when planning and implementing control measures for donkeys-associated leptospirosis.

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Most of the information about leptospirosis was obtained from experimental infections with rodents, which in spite of being relevant, do not provide all the answers about the disease in animals and human beings, given the variability of interactions which exist between the agent and the different hosts. Therefore, the objective of the present study was to verify the pathogenesis of the infection in native breeds of sheep of Brazil challenged with a strain of the serogroup Pomona.  A total of 10 sheep were divided into two groups with five animals according to the breed. In each group four sheep were challenged by intraperitoneal route with a strain of the serogroup Pomona and one was used as control. Sheep were monitored for 60 days, with collection of blood for serologic diagnosis, as well as vaginal fluid and urine for microbiological and molecular analyses. After this period the animals were submitted to euthanasia and necropsy, with collection of tissues for microbiological, molecular and histopathologic diagnosis. All the challenged sheep presented anti-Leptospira antibodies. Crossbred sheep presented a lower concentration of titers and the antibodies were detected for a shorter period of time when compared to the Santa Inês sheep, with statistical difference in the concentration of the titers on the days 15 (p<0.05), 45 (p<0.05) and 60 (p<0.05) post-infection. There was no significant difference between the groups when comparing the positivity rates of the microscopic agglutination test (MAT) (p>0.05). Eight positive reactions in the urine and vaginal fluid PCR were detected in both groups, being four (50%) in urine and four (50%) in the vaginal fluid, however without statistical difference (p>0.05). In both groups there was a greater proportion of PCR positive samples in kidneys (71.4%) in relation to uterus (28.6%), however without significant difference (p>0.05). There was no significant difference between the groups when comparing the positivity rates of the PCR (p>0.05). The isolation of leptospires from the urine and kidney of a crossbred sheep was possible. Therefore, it is possible that the native sheep, especially the crossbred, may have a relation of resistance with strains of the serogroup Pomona. However the intensity and duration of this relation need to be elucidated and longer-lasting investigations of natural and experimental infections are necessary in order to determine the epidemiological nature of this relation.