Epidemiological and clinicopathological findings of feline immunodeficiency virus and feline leukemia virus infections in domestic cats from the Brazilian semiarid region.

Feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) are retroviruses of great importance for domestic cats with a worldwide distribution. A retrospective study was conducted to determine the epidemiological and clinicopathological aspects of the infection by FIV and FeLV in cats from the Brazilian semiarid region. Cats treated between 2011 and 2021 at the teaching veterinary hospital of the Federal Rural University of the Semi-Arid Region that were submitted to a point-of-care (POC) test to detect anti-FIV IgG antibodies and FeLV antigen were enrolled in the study. Overall, 454 cats were selected, of which 30.2% [95% CI = 26.0% - 34.3%] were FIV-positive, 1.1% [95% CI = 0.9% - 1.2%] were FeLV-positive, and 0.7% [95% CI = 0.1% - 1.3%] were coinfected by both retroviruses. No statistical association was found between the studied retroviruses (P = 0.144). Multivariable analysis detected significant associations between FIV infection and male sex [OR = 5.7, 95% CI = 3.0-10.7, P < 0.0001), age between 19 and 78 months [OR = 5.2, 95% CI = 2.2-12.1, P < 0.0001], age greater than 78 months [OR = 12.8, 95% CI = 5.1-31.9, P < 0.0001], crossbreed [OR = 4.1, 95% CI = 1.2-13.4, P = 0.021], the presence of oral disease [OR = 2.1, 95% CI = 1.3-3.4, P = 0.004], reduced red blood cell (RBC) count [OR = 3.7, 95% CI = 1.9-7.2, P < 0.0001], and an albumin:globulin (A:G) ratio lower than 0.6 [OR = 3.4, 95% CI = 1.6-7.1, P = 0.001]. No statistical analyses were performed for FeLV infection due to the low number of positive animals. In the quantitative analyses of hematological parameters, FIV-positive cats presented lower values for RBC, hemoglobin, hematocrit, lymphocytes, and platelets compared to the negative animals. In the biochemical profile, cats infected with FIV showed higher creatinine, urea, total protein, and globulin values, while lower values for albumin and A:G ratio were observed (P < 0.05). The findings of this study characterized the prevalence, clinicopathological findings, and risk factors associated with FIV and FeLV in cats from the Brazilian semiarid region. They may help support veterinary practitioners in diagnosing feline retroviruses. The FIV prevalence observed is among the highest reported in Brazil, demonstrating the need for prevention and control strategies for this retrovirus.

Distribution, seroprevalence and risk factors for bovine brucellosis in Brazil: Official data, systematic review and meta-analysis.

Bovine brucellosis is an endemic disease in Brazil, and evidence-based assessments of the available literature on its seroprevalence and risk factors are limited. The aim of this study was to systematically review and summarize studies related to seroprevalence and risk factors of bovine brucellosis in the entire Brazil, in addition to comparing published data with the most recent official reports. Articles available in scientific databases and published between October 2006 and October 2021 were evaluated. Forty-five publications were included in the meta-analysis on the seroprevalence of brucellosis and 29 publications in the review on risk factors. The largest number of publications was found for the State of Mato Grosso do Sul (n=4), and the highest and lowest seroprevalences were observed in Acre (11%; 95% CI: 8.0-14.0%) and in the Federal District (0.4%; 95% CI: 0.2-0.7%). The main risk factors were the purchase of animals for breeding, vaccination, the number of heifers (female ≥2 years), the presence of calving paddocks and the occurrence of abortions. The need for new official studies has been suggested to determine the true prevalence of bovine brucellosis in Brazil, supported by the National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis.

Strong Evidence of the Role of Donkeys in the Epidemiology of Leptospira spp. in Semiarid Conditions.

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.

Herd and animal level prevalences and risk factors for Neospora caninum infection in cattle in the state of Paraíba, northeastern Brazil.

Bovine neosporosis is a globally important disease, causing abortions and significant economic losses. In Brazil, studies on neosporosis in cattle are few and based on limited samples and/or from limited areas. We aimed to determine the herd and animal levels seroprevalence and associated factors for Neospora caninum infections in cattle from the state of Paraíba, Northeastern Brazil, using a planned sampling. Herds (n = 434) and cows aged ≥24 months (n = 1891) were randomly selected, and serum samples were tested with the immunofluorescence antibody test (IFAT) using as cut-off point the antibody titer 200. Herd-level and animal-level seroprevalences were 17.8% (95% CI = 14.3%-21.8%) and 18.1% (95% CI = 14.7%-22.1%), respectively. The factors associated with N. caninum infection were farm located in the Sertão mesoregion (Prevalence ratio [PR] = 2.37), mixed production (PR = 1.64), herd size of 34-111 animals (PR = 3.50) and herd size >111 animals (PR = 6.14). The results indicate high N. caninum circulation in the bovine population of the state of Paraíba, semiarid of Brazil, mainly in the Sertão mesoregion, where the highest apparent herd and animal-level prevalences of positive herds were identified. Control strategies should be adopted to mitigate the impact of disease on cattle production, as well as it's suggested the encouragement of conducting surveys in wildlife from Caatinga biome, mainly canids, to provide information on the importance of these animals on the epidemiology of bovine neosporosis.

Clinical, histopathological, and molecular findings for Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goats under semiarid conditions.

The objective of this study was to report the occurrence of Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goats, via description of their clinical presentation, histopathological findings, and molecular identification of the infectious agent. Screening was performed using IS900 real-time PCR (qPCR) in milk samples from 179 properties in the semiarid of Northeast region of Brazil. Pooled milk samples from all lactating goats from processing plants were submitted to molecular diagnosis. One property had a positive result at qPCR. The production unit which had the positive sample for MAP was located, and an on-site visit to this property was performed to collect individual milk samples, seven of which tested MAP positive by IS900 qPCR. With permission from the owner, two goats (Animal 1 was positive and Animal 2 was negative on first qPCR for MAP) were acquired and euthanized. Animals 1 and 2 had milk and portions of the duodenum, ileum, colon, and mesenteric lymph nodes positive at qPCR for MAP. Animal 1 also had MAP DNA detected in part of the jejunum and cecum. In animal 2, the ileocecal valve tested positive. MAP was not detected in the blood or feces of either animal; however; it was confirmed for the association of clinical findings, histopathology, and qPCR. The gene IS900 from the positive samples were sequenced and showed a 99% similarity with MAP. The MAP was identified for the first time in the goat milk and tissues in the semiarid region of Northeast Brazil.

Factors associated with small ruminant lentivirus infection in goat herds from Pernambuco state, Northeast region of Brazil.

Serum samples (n = 1532) were collected between May 2011 to April 2012 from goats from 76 herds (49 from dairy farms and 27 herds for genetic improvement) from three geographical regions from the state of Pernambuco, Brazil: Zona da Mata, Agreste, and Sertão. Samples were processed using agar gel immunodiffusion test, with p28 CAEV antigen. The objective was to determine the risk factors for small ruminant lentivirus (SRLV) in dairy goats and goats with high genetic value. Overall, seroprevalence was 13.7% (210/1532) [95% CI: 12-15.4%] in animals and 67.1% (51/76) [95% CI: 56.5%- 77.7%] in herds. In dairy farms the seroprevalence was 73.5% (36/49) [95% CI: 61.1%- 85.8%], and in properties with animals of high genetic value it was 55.6% (15/27) [95% CI: 36.8%- 74.3%]. Robust Poisson regression analysis adjusted by the random effect of the herd showed that risk factors were: importing bucks from another Brazilian state (prevalence ratio [PR] = 4.73 [95% CI: 2.05; 10.88]), not isolating sick animals (PR = 3.27 [95% CI: 2.24; 4.76]), and participating in fairs/animal crowding (PR = 1.52 [95% CI: 1.09; 2.11]). Prevalence results show that SRLV is present in caprine herds in the state of Pernambuco and identified risk factors are strongly related to animal transit. Considering the epidemiological situation, the first step for mitigating the consequences of this disease would be controlling animal transit.

Epidemiology of Leptospira sp. Infection: Current Status, Insights and Future Prospects.

In recent decades, the scientific community has been faced with an increased risk of emerging or re-emerging zoonotic diseases, such as leptospirosis, mainly originating from anthropic actions [...].

New insights on Leptospira sp. infection in ewes maintained in field semiarid conditions.

Leptospirosis is poorly studied in small ruminants raised in field semiarid conditions. In this study we compared serological, bacteriological and molecular diagnostic methods in ewes maintained in field Brazilian semiarid conditions. Blood, vaginal fluid and urine samples were collected from 60 Morada Nova ewes raised in a semi-intensive system 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 eight (13.33%) animals analyzed by MAT at reciprocal titer 25 (cut-off 25), while Leptospira sp. DNA was detected in urine or vaginal fluid of 56 animals (93.33%). There was growth of leptospires in 10 urine cultures and in 11 vaginal fluid cultures, however, two of urine (2/60-3.33%) and eight cultures of vaginal fluid (8/60-13.33%) were confirmed by PCR. Two samples of vaginal fluid (one of each animal) were submitted to sequencing demonstrating 99% similarity with L. santarosai and L. interrogans. The highest MAT sensitivities were obtained with reciprocal titer 25 (cut-off 25) compared to 50 and 100. The performance of different diagnostic techniques for leptospirosis in ewes raised in field semiarid conditions allowed a better evaluation of the herd, as well as made it possible to identify carrier animals. Genital route may be important for efficient transmission and without dependence on environmental factors in ewes from semiarid, as well as it's highlighted that titer 1:25 in serology was more efficient, indicating its use in ewes in field semiarid conditions.

Global Prevalence of RNA-Positive Horses for Hepacivirus (EqHV): Systematic Review and Meta-Analysis.

Equine hepacivirus (EqHV) belongs to the Flaviviridae family, genus Hepacivirus and has the greatest genomic identity with the hepatitis C virus (HCV), one of the main causes of chronic liver disease in humans. Due to the limited applicability of studies of HCV in animal hosts, the interest in studies of characterization of viral homologues has been growing. For this reason, we performed a systematic review of the literature with meta-analysis of the prevalence of EqHV and genetic sequencing studies. Twenty-three studies from four different continents were analyzed. The OR meta-analysis (0.98; 95% CI = 0.69-1.39) showed no influence of sex (female or male) on the risk of infection. Variables associated with EqHV infection were indirectly related to animal management such as transport, reproductive practices, among others. The combined prevalence of positive animals was 7.88% (95% CI = 5.23-11.69%), with the highest proportions in Asia (16.13%; 95% CI = 7.79-30.43%), followed by South America (12.03%; 95% CI = 9.58-15.01%), Africa (8.69%; 95% CI = 6.71-11.20%), and Europe (3.63%; 95% CI = 2.10-6.22%). However, these results represent the regional stratification of the epidemiological studies for EqHV published to date and, therefore, cannot extrapolate to determine the continental prevalence of EqHV. It is therefore important to update the systematic review as further research becomes available.

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.

High herd-level seroprevalence and associated factors for bovine leukemia virus in the semi-arid Paraíba state, Northeast Region of Brazil.

Epidemiological surveys that investigate infectious diseases such as enzootic bovine leukosis (EBL) are important. Furthermore, estimating the prevalence of such infectious diseases and associated factors is key to assess the disease impact and design control programs. In this study, we identified a high herd-level seroprevalence of EBL in cattle from the semi-arid Paraíba state, Northeast Region of Brazil, using a planned cross-sectional survey. Herd-level and animal-level prevalence were estimated using a two-stage random sampling survey. In total, 2067 cows aged ≥24 months from 400 herds were sampled. An enzyme-linked immunosorbent assay was used to detect specific antibodies directed to the bovine leukosis virus gp51 antigen in both individual and pooled sera. The herd-level and animal-level prevalence was 23.4 % (95 % CI = 19.2-28.1 %) and 10.8 % (95 % CI = 7.5 %-15.3 %), respectively. There were no significant clusters of positive herds (within a radius of 2 km). The factors associated with herd-level prevalence were the exclusive use of hand milking (prevalence ratio [PR] = 1.88), herd size (PR = 1.005), artificial insemination (PR = 2.03), purchase of animals in the previous year (PR = 1.87), and peri-urban farms (PR = 2.09). Prevention measures should be applied at the herd-level, particularly for farms located in peri-urban areas, focusing on good hygiene in hand milking, robust practices and standards for artificial insemination, and serological testing of animals prior to purchase.

Antibody detection and molecular analysis for Mycobacterium avium subspecies paratuberculosis (MAP) in goat milk: Systematic review and meta-analysis.

Paratuberculosis is an incurable infectious disease that affects several species, including goat (Capra hircus). The etiologic agent is Mycobacterium avium subspecies paratuberculosis (MAP) that has tropism for the intestine, causing anorexia, progressive weight loss and death. In goats, the main transmission route is the ingestion of water and food contaminated by infected feces. Affected animals also eliminate the agent through milk, with a potential biological risk to public health. Thus, the aim of this study was to conduct a research of the literature available in electronic media for a systematic review, followed by a meta-analysis of the results found on prevalence and diagnostic tests adopted in the detection of MAP antibodies and DNA in goat milk. The following search parameters were used: "Mycobacterium avium subsp. paratuberculosis" AND (goat OR small ruminant) AND (milk OR pasteurized milk). Strictly obeying pre-established criteria, 437 articles were selected from the respective electronic databases of scientific content: ScienceDirect (285), PubMed (68), Web of Science (60) and Scopus (24), of which nine papers were elected to the construction of the systematic review and meta-analysis. The prevalence of MAP antibodies in milk detected by milk-ELISA ranged from 1.1 to 67.7% and the prevalence of MAP DNA in goat milk detected by MAP-specific polymerase chain reaction (PCR) ranged from 1.94 to 37.74%. A meta-analysis indicated a combined MAP infection prevalence of 8.24%, but with high heterogeneity among study findings (I2 = 98.7%). The identification of the MAP in goat milk implies the need for surveillance of the agent in order to prevent economic losses and impact on public health.

Serological, molecular and bacteriological approaches for detecting Leptospira sp. carrier rams maintained in semiarid conditions.

Even in the adverse environmental conditions of the semiarid region, leptospires can survive and spread by alternative routes of transmission, such as sexual in ewes, however, there is no data on rams. Thus, the present study aimed to evaluate the use of serological, molecular and microbial tools applied to diagnosis of Leptospira sp. Infection in rams maintained in semiarid conditions. Biological samples of urinary (urine, kidney and bladder) and genital (vas deferens, epididymis tail and vesicular gland) tracts were collected from 40 slaughtered rams for polymerase chain reaction (PCR) and bacterial isolation, as well as blood samples for antibody detection through microscopic serum agglutination test (MAT). Anti-Leptospira antibodies were found in five (12.5%) animals with antibody titer of 50 and 2 (5%) for the titer 100 for serogroups Pyrogenes, Ballum, Icterohaemorrhagiae and Australis. Leptospira sp. DNA was found in PCR of organs and urine of 30 (75%) animals. Overall, 240 fragments of organs from the urinary and genital tracts and urine were evaluated, with 93 (38.7%) positive samples, being 48/120 (40%) for the urinary tract and 45/120 (37.5%) for the genital. There was no statistically significant difference between the tracts. A bladder sample was sent for sequencing and showed 99% similarity with L. interrogans. Of the 240 cultures evaluated, 59 (24.5%) had leptospire growth, being that 23 (39%) were confirmed in PCR. Considering the PCR of organs and urine and bacterial growth as gold standards, the cut-off 50 in MAT showed greater sensitivity when compared to cut-off 100, regardless of the material used. The great proportion of leptospiral DNA in organs, urine and culture and bacterial growth from the genital tracts reinforce its importance as an extra-renal site and highlights the possible role of rams in venereal transmission, as well as the sensitivity of the cut-off 50 suggested its adoption in the serology of rams maintained in semiarid conditions.

Didelphis albiventris as a carrier of Leptospira sp. in the central nervous tissue in the semiarid region of Northeast, Brazil.

Leptospirosis has been investigated in several species of wild animals. The white-eared opossum (Didelphis albiventris) is a mammal common in the brazilian semi-arid, so, this study aimed to investigate its role in the occurrence of the leptospirosis in the region Northeast of Brazil. 12 animals were used, from which samples were collected for the attempt of isolation, molecular detection and serological examination. There was no microbial growth, nor were any anti-Leptospira sp. antibodies found in the serological samples. The PCR detected leptospiric DNA in the central nervous system (CNS) of five animals (41.7 %). The gene in one of the samples was sequenced and showed identity with Leptospira interrogans. The presence of Leptospira sp. in the CNS of Didelphis albiventris does not allow the characterization of the studied animals as reservoirs with potential for transmission of the pathogen in the region, however it represents a site that needs to be further investigated.

Leptospira sp. vertical transmission in ewes maintained in semiarid conditions.

Leptospirosis is a globally distributed disease associated with reproductive failures in livestock; however, its pathogenesis has not been fully elucidated. Results from the present study indicate there is a presence of Leptospira sp. in organs and fluids of fetuses from ewes slaughtered in the semiarid region of Brazil. Twenty-nine fetuses from 23 ewes determined to be Leptospira sp.-positive using PCR were sampled (14 and 15 in dry and rainy seasons, respectively). Fetal samples of blood, central nervous system (CNS), lung, liver, spleen, stomach contents, peritoneal fluid, kidney, bladder, urine and reproductive system were collected. Diagnostic methods included the microscopic agglutination test (MAT), polymerase chain reaction (PCR) and bacterial isolation. Of the 29 fetuses, 24 (82.8 %) had at least one Leptospira sp.-positive organ or fluid, as determined using PCR, and of a total of 209 samples, 62 (29.7 %) contained leptospiral DNA. Of the 99 samples collected during the dry season, 42 (42.4 %) were positive, and of 110 samples collected during the rainy season, 20 (18.2 %) were positive (P = 0.0001). There was deoxyribonucleic acid (DNA) sequencing of three samples of kidney, CNS and liver, and in all of these, there was 99.3 % similarity with Leptospira interrogans. Leptospires were present in cultures of pooled samples from fetuses with deformities. Results indicate there is vertical (maternal-to-fetus) transmission which would represent an alternative transmission route for the spread of Leptospira sp. in ewes, suggesting molecular detection is essential in the investigation of leptospirosis in fetuses to identify animals that have been infected with this bacterium.

Factors associated with the seroprevalence of caseous lymphadenitis in sheep from Northeastern Brazil.

Caseous lymphadenitis (CL) is one of the main infectious diseases in sheep, responsible for great economic losses, mainly in Northeast region of Brazil, which has the largest sheep flock in the country. Thus, the aim of this survey was to determine the factors associated with the seroprevalence of this disease in sheep from Northeastern Brazil using a planned sample of flocks and animals. Samples were collected from 2312 adult and young sheep of both sex from 196 farms, located in 51 municipalities in five Northeastern Brazilian states (Ceará, Paraíba, Piauí, Rio Grande do Norte, and Sergipe). Serological diagnosis was performed using the indirect ELISA technique. Factors associated with seropositivity were identified by variables extracted from epidemiological questionnaires administered to breeders, using univariable and multivariable analyses. Factors associated with prevalence were purebred sheep (Prevalence ratio - PR = 1.189; P = 0.017), ram acquisition from animal expositions (PR = 1.192; P = 0.020), offspring is separated from ewes (PR = 1.132; P = 0.048), water supplied to sheep from ponds (PR = 1.365; P = 0.002), and delayed disposal of infected animals (PR = 1.263; P = 0.027). Flock-level and animal-level prevalences were 93.88 % (95 % CI = 89.60-96.46%) and 37.46 % (95 % CI = 35.51-39.45%), respectively. In view of the high prevalence found here and based on the associated factors, the implementation of an efficient CL control programme in Northeastern Brazil is recommended.

Serological evidence of Leptospira sp. in humans from Fernando de Noronha Island, Brazil.

The prevalence of leptospirosis in humans is highly variable, being influenced by climatic factors, the presence of reservoirs, occupational exposure, recreational activity, and socioeconomic conditions. The objective of this study was to estimate the prevalence of Leptospira sp. and identify the predominant human serovars on the island of Fernando de Noronha, Brazil, based on a microscopic agglutination test. The prevalence of anti-Leptospira antibodies was 1.17% (4/341; I.C. 0.46%-2.98%), with the predominance of serovars Icterohaemorrhagiae, Javanica, Mini and Louisiana. This is the first study on the occurrence of antibodies against Leptospira sp. in humans in Fernando de Noronha and highlights the need to implement control and prevention strategies in this island environment.

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.

High frequency of seropositive and carriers of Leptospira spp. in pigs in the semiarid region of northeastern Brazil.

Carrier animals are considered key in the transmission cycle of leptospirosis. Although investigations have been carried out on several species, the role of pigs in the epidemiology of the disease is still poorly studied in the semi-arid region. Thus, the objective of this study was to determine the presence of Leptospira spp. in the genitourinary tract of pigs intended for slaughter. Fifty pigs were used: adults and unvaccinated. Samples of the kidney, urine, and vaginal fluid were collected for the molecular detection of Leptospira spp. and blood samples for the serological test. The molecular test was performed using the polymerase chain reaction (PCR), and the serological test was performed with the microscopic agglutination test (MAT). Samples with DNA amplification were submitted to genetic sequencing. Twenty (40%) animals were found with anti-Leptospira spp. antibodies, and the majority of the reactions (50%) occurred for the serogroup Tarassovi. Leptospiral DNA was found in the tissue of 11 (22%) pigs. The gene from a urine sample was sequenced and showed similarity to L. borgpetersenii. The results evidenced a high rate of porcine carriers; therefore, they appear to be important sources of agent infection, being potential transmitters of the disease to other animal species and man.

Seroepidemiological study of Caseous lymphadenitis in sheep from the Northeast region of Brazil using an indirect ELISA.

The objective of this study was to determine the frequency of seropositivity Corynebacterium pseudotuberculosis in sheep in five states of northeastern Brazil, using an indirect enzyme-linked immunosorbent assay (i-ELISA). Young and adult sheep of both sexes were used. Blood samples were collected from 2638 sheep from 223 herds across all states. For the i-ELISA, antigens produced from the strain of C. pseudotuberculosis BRM 029971, a bacterial isolate from the Northeast region of Brazil, were used. Sensitivity and specificity indexes were calculated for the validation of the test, using as reference 49 and 134 serum samples from sheep known to be positive and negative, respectively. The i-ELISA presented four false-negative and four false-positive results, showing a specificity of 97.01%, a sensitivity of 91.84%, and an accuracy of 95.63%. These results were calculated based on an optical density (OD) cutoff point = 0.138. Of the 2638 sheep tested, 996 (37.76%, 95% CI = 35.93-39.62%) were seropositive, and of the 223 evaluated herds, 210 (94.17%, 95% CI = 90.28-96.56%) seropositive. The i-ELISA showed adequate sensitivity and specificity, proving to be a useful tool in the diagnosis of caseous lymphadenitis (CLA) in sheep. Infection by C. pseudotuberculosis, determined by serology, is disseminated in the sheep herds in the states of Northeast Brazil. Thus, there is a need to implement effective control measures that prevent the spread of infectious agents.