Molecular and serological prevalence of Leptospira spp. among slaughtered cattle and associated risk factors in the Bahr El Ghazal region of South Sudan.

INTRODUCTION: Leptospirosis is a neglected emerging and zoonotic disease reported worldwide. This study sought to determine the molecular and serological prevalence of Leptospira spp. and the associated risk factors in slaughtered cattle from the Bahr El Ghazal region of South Sudan. MATERIALS AND METHODS: Between January 16th and February 25th, 2023, blood and urine samples were collected from 402 cattle at the Lokoloko Municipal Slaughterhouse in Western Bahr El-Ghazal State. Serum samples were tested using the microscopic agglutination test (MAT), with a panel of 12 serovars (sv) from 12 serogroups (sg) and 4 species (spp) of Leptospira spp. These serovars had been previously identified in Sudan and the East African region. Simultaneously, 400 corresponding urine samples were screened using qualitative real-time polymerase chain reaction (PCR) to detect the shedding of Leptospira spp. in urine. To identify the associated risk factors, the age, sex, breed and body condition score of each sampled cattle was noted at the time of sampling and subsequently analysed using logistic regression models. RESULTS: Among the 402 serum samples screened, a substantial 81.8% (329/402, 95% CI 77.9-85.3) displayed seropositivity for Leptospira spp. with a MAT titre ≥ 100. The prevalence of urine shedding determined by PCR was 6% (23/400, 95% CI 3.8-8.4), while probable recent leptospirosis with a MAT ≥ 1:800 was observed in 33.1% (133/402, 95% CI 28.6-37.8) of the cattle. Multiple reactions were detected in 34.8% (140/402, 95% CI 30.6-39.5) serum samples. The seropositivity was against L. borgpetersenii sg. Tarassovi (78.6%; 316/402, 95% CI 74.4-82.3), followed by L. borgpetersenii sg. Ballum at 20.4% (82/402, 95% CI, 16.7-24.4%), L. kirschneri sg. Autumnalis At 8.7% (35/402, 95% CI 5.7-11.7), L. interrogans sg. of Pomona at 7.0% (28/402, 95% CI 4.5-9.5), and L. interrogans sg. Hebdomadis was 5.0% (20/402, 95% CI 2.8-7.2). Several risk factors are associated with seropositivity. Older animals (≥ 2 years) had 2.0 times greater odds (95% CI 1.14-3.5) of being seropositive than younger animals (< 2 years), P-value = 0.016. Female animals demonstrated 2.1 times greater odds (95% CI 1.2-3.6) of seropositivity than males did (P-value = 0.008). Additionally, Felata/Mbororo cattle exhibited 2.4 times greater odds (95% CI 1.3-4.5) of being seropositive than did local Nilotic cattle (P-value = 0.005). The agreement between the MAT and PCR results was poor, as indicated by a kappa statistic value of 0.001 and a P-value of 0.913. But there was a moderate agreement between MAT high titres ≥ 800 and PCR positivity with a kappa statistic value = 0.501 and a P-value < 0.001. CONCLUSION: In addition to the high seroprevalence, Leptospira spp. were found in the urine of slaughtered cattle, suggesting that leptospirosis is endemic to the study area. This finding underscores the significance of cattle as potential sources of infection for slaughterhouse workers, the general public, and other animal species. To address this issue effectively in the Bahr El Ghazal Region and South Sudan, a comprehensive strategy involving a multidisciplinary approach is essential to minimize disease among animals, hence reducing potential zoonotic risks to humans.

THREE CASES OF CLINICAL LEPTOSPIROSIS IN PATAGONIAN MARAS (DOLICHOTIS PATAGONUM).

Rodents are typically viewed as asymptomatic reservoirs for leptospirosis infection, as clinical disease in rodents is rarely described. This report includes three separate cases of leptospirosis in Patagonian maras (Dolichotis patagonum) over a 3-yr period in multiple locations within a single zoo. All three cases presented with varying clinical signs including lethargy, conjunctival hyperemia, hyperbilirubinemia, and presumed renal azotemia. Infection with Leptospira spp. was diagnosed antemortem by PCR on whole blood (n = 1, Case 1) or urine (n = 2, Cases 2 and 3). Leptospira antibody titers measured by serum microagglutination testing (n = 3) were elevated or increased in all three animals over a 1-3-wk period for Leptospira serovars Bratislava and Hardjo (Case 1) and Grippotyphosa (Case 2 and 3). Two of the three animals responded to treatment with penicillin and doxycycline and supportive care, whereas one animal did not respond to treatment. Postmortem findings in this individual included conjunctivitis, chemosis, dehydration, icterus, tricavitary serosanguinous effusions, necrotizing hepatitis, diffuse pulmonary congestion, and edema. Immunohistochemical examination identified scattered Leptospira organisms within hepatocytes and renal tubular epithelial cells. A wild raccoon (Procyon lotor) at the institution tested positive by PCR on kidney tissue for the same Leptospira spp. serovar and was the suspected source of infection. This case series highlights the clinical importance of leptospirosis as a differential for Patagonian maras presenting with lethargy, ocular signs, acute hepatic disease, and azotemia.

Detection of Leptospira kirschneri in a short-beaked common dolphin (Delphinus delphis delphis) stranded off the coast of southern California, USA.

BACKGROUND: Pathogenic Leptospira species are globally important zoonotic pathogens capable of infecting a wide range of host species. In marine mammals, reports of Leptospira have predominantly been in pinnipeds, with isolated reports of infections in cetaceans. CASE PRESENTATION: On 28 June 2021, a 150.5 cm long female, short-beaked common dolphin (Delphinus delphis delphis) stranded alive on the coast of southern California and subsequently died. Gross necropsy revealed multifocal cortical pallor within the reniculi of the kidney, and lymphoplasmacytic tubulointerstitial nephritis was observed histologically. Immunohistochemistry confirmed Leptospira infection, and PCR followed by lfb1 gene amplicon sequencing suggested that the infecting organism was L.kirschneri. Leptospira DNA capture and enrichment allowed for whole-genome sequencing to be conducted. Phylogenetic analyses confirmed the causative agent was a previously undescribed, divergent lineage of L.kirschneri. CONCLUSIONS: We report the first detection of pathogenic Leptospira in a short-beaked common dolphin, and the first detection in any cetacean in the northeastern Pacific Ocean. Renal lesions were consistent with leptospirosis in other host species, including marine mammals, and were the most significant lesions detected overall, suggesting leptospirosis as the likely cause of death. We identified the cause of the infection as L.kirschneri, a species detected only once before in a marine mammal - a northern elephant seal (Mirounga angustirostris) of the northeastern Pacific. These findings raise questions about the mechanism of transmission, given the obligate marine lifestyle of cetaceans (in contrast to pinnipeds, which spend time on land) and the commonly accepted view that Leptospira are quickly killed by salt water. They also raise important questions regarding the source of infection, and whether it arose from transmission among marine mammals or from terrestrial-to-marine spillover. Moving forward, surveillance and sampling must be expanded to better understand the extent to which Leptospira infections occur in the marine ecosystem and possible epidemiological linkages between and among marine and terrestrial host species. Generating Leptospira genomes from different host species will yield crucial information about possible transmission links, and our study highlights the power of new techniques such as DNA enrichment to illuminate the complex ecology of this important zoonotic pathogen.

Seroprevalence of Leptospira antibodies in dogs and cats from Santa Fe, a city in East-Central Argentina endemic for leptospirosis.

This study examines household pets as potential epidemiological links between environments contaminated with pathogenic leptospires and humans in Santa Fe, Argentina. The aims of our study were: (a) to characterize the habits and exposure to environmental sources of leptospirosis in the population of dogs and cats attending to municipal spay and neutering campaigns in Santa Fe, Argentina, (b) to assess the seroprevalence of anti-Leptospira antibodies in asymptomatic dogs and cats, (c) to evaluate factors that could increase seropositivity, and (d) to identify spatial clusters of seropositive dogs and cats in the capital city of Santa Fe. From May to November 2022, a cross-sectional serosurvey was conducted during municipal spaying/neutering campaigns. Eligible household dogs and cats were over 6 months old, apparently healthy, and not vaccinated against leptospirosis in the past 6 months. We used microagglutination test (MAT) to assess anti-Leptospira antibodies using a panel of 10 reference strains. We used generalized linear mixed effects models (GLMM) to examine individual and census tract-level risk factors for seropositivity, and local Moran's I statistic for spatial clusters. Results showed higher leptospiral antibody prevalence in dogs (18.2 %) than cats (3.6 %, p = 0.002). Dogs with street access had higher likelihood of being seropositive (OR: 3.8, 95 % CI: 1.2; 11.9), and areas with chronic poverty showed an elevated risk of presenting seropositive animals (RR: 4.0, 95 % CI: 1.1; 14.4). Spatial analysis didn't reveal significant seropositivity clusters among census tracts. These findings shed light on widespread Leptospira seropositivity in pets in this endemic region. Understanding seroprevalence and risk factors can guide public and veterinary health strategies, emphasizing increased leptospirosis vaccination for dogs in vulnerable areas and promoting responsible pet care.

Estimation of economic losses due to leptospirosis in dairy cattle.

There are few studies that effectively quantify the economic losses resulting from problems caused by leptospirosis in naturally infected dairy cattle. Given this gap, the objective of this study was to propose and apply a method to quantify the economic losses resulting from productive and reproductive problems in a commercial dairy herd naturally infected by Leptospira spp. For this study, the zootechnical and economic indicators at a property with Jersey cattle were analyzed during the period from 2014 to 2017. The leptospirosis outbreak occurred in 2014, and the therapeutic approach was carried out between 2015 and 2017, with the latter considered the year of control of the outbreak. The adopted integrated control strategy consisted of dividing the herd according to the serological results obtained through the microscopic agglutination test, the treatment of reagents with streptomycin, and vaccination against leptospirosis of non-reagent heifers and cows. The method used to evaluate the economic indicators of the property was the calculation of the gross margin by taking into account the implicit and explicit cost parameters associated with the manifestation of leptospirosis. The prevalence rate of leptospirosis decreased from 49.4 % in 2015 to 21.6 % in 2017. There was a reduction in the abortion rate (from 40.00 % in 2014 to 9.00 % in 2017), in the stillborn rate (from 2.63 % in 2014 to 1.69 % in 2017) and an increase in the calving rate (from 65.00 % in 2014 to 86.00 % in 2017). In addition, there were increases in the number of lactating cows (from 38 in 2014-57 in 2017) and the mean times of lactation duration, which increased from 275 days in 2014-295 days in 2017. As a result, the average annual production of milk increased from 164,655 liters in 2014-248,521 liters in 2017. In 2014, when treatment hadn't yet started, the gross margin per liter of milk sold, considering implicit and explicit costs, was US$0.00. In 2015 and 2016, US$0.27 and US$0.30 were obtained, respectively, for this variable. In 2017, with the disease under control on the property, the gross margin per liter of milk reached US$0.36. The gross margin per liter of milk sold was higher in the period when the disease was controlled, showing losses of up to 84 % of the gross margin during the outbreak. Immediate treatment of positive cows and preventive measures had a significant impact on improving the productive and economic efficiency of the property.

Antibodies against Leptospira spp. in Free-living and Captive Broad-snouted Caiman (Caiman latirostris) and Free-living Yacare Caiman (Caiman yacare) in Brazil.

We evaluated antibodies against Leptospira spp. in both free-living and captive Caiman latirostris from Atlantic Forest, and free-living Caiman yacare from Pantanal, Brazil, by using a microscopic agglutination test. Overall seropositivity was 17%, with rates of 36% in captive C. latirostris (n=4/11) and 18% in free-living C. yacare (n=4/22).

Leptospira borgptersenii and Leptospira interrogans identified in wild mammals in Rio Grande do Sul, Brazil.

Leptospira spp. are bacteria responsible for leptospirosis, a zoonotic disease with considerable impacts on the economy, animal health, and public health. This disease has a global distribution and is particularly prevalent in Brazil. Both rural and urban environments are habitats for Leptospira spp., which are primarily transmitted through contact with the urine of infected animals. Consequently, domestic and wild species can harbor these prokaryotes and serve as infection sources for other hosts. In the context of wild animals, there is a dearth of molecular studies elucidating the roles of various animal and bacterial species in the epidemiology of leptospirosis. Therefore, this study aimed to evaluate the presence of Leptospira spp. DNA in different species of free-living and captive wild animals and to assess the phylogenetic relationships of the identified microorganisms in Rio Grande do Sul, Brazil. The samples were evaluated for the presence of the gene lipL32 by polymerase chain reaction (PCR) and sequencing of the amplified fragment after which phylogenetic analyzes were carried out. DNA from Leptospira spp. was extracted from kidney tissue from wild animals (Mammalia class). Pathogenic Leptospira spp. DNA was detected in 9.6% (11/114) of the samples, originating from nine species of wild animals, including the white-eared opossum (Didelphis albiventris), skunk (Conepatus chinga), geoffroy's cat (Leopardus geoffroyi), margay (Leopardus wiedii), pampas fox (Lycalopex gymnocercus), capybara (Hydrochoerus hydrochaeris), common marmoset (Callithrix jacchus), neotropical river otter (Lontra longicaudis), and european hare (Lepus europaeus). Phylogenetic analysis revealed the presence of Leptospira borgpetersenii and Leptospira interrogans in these animals. This research is the first study contributing to the epidemiology of leptospirosis by identifying L. borgpetersenii and L. interrogans in free-living and captive wild animals in Rio Grande do Sul, Brazil, potentially acting as bacterial reservoirs. Additionally, our findings can inform sanitary measures for controlling and preventing the disease, thereby safeguarding public health.

Current knowledge on leptospirosis in cats: A systematic review with metanalysis on direct detection, serological response, and clinical data.

Leptospirosis is a neglected bacterial zoonosis that affects a wide range of mammals, with important implications from a One Health perspective. Over the past years feline leptospirosis has gained increased attention in the scientific community. Here we describe a systematic review with meta-analysis that followed the PRISMA guidelines, with an additional PROSPERO registration. The study provides global seropositivity, urinary shedding rates, global serogroup distribution, descriptive data of leptospires that had been isolated from cats and clinical and laboratory features presented by symptomatic cats with acute disease. The search was carried out in six different databases, with the identification of 79 reports describing leptospiral infection in cats. The pooled frequency of seroreactive cats was 11% (95% CI: 9%-13%), with Javanica and Pomona as the most frequent serogroups found. Frequency for urinary shedding was 8% (95% CI: 5%-10%), with L. interrogans identified in most samples. A total of 16 isolates were isolated from cats, with Bataviae as the most frequent serogroup. Twenty symptomatic cats with confirmed leptospiral infection were identified. Anorexia, lethargy, polydipsia, and bleeding disorders were the clinical signs most frequently reported. The results suggest that cats from some locations are exposed to leptospires and may act as urinary shedders of this pathogen, thus indicating a possible role of this species in disease transmission. Clinical data indicates that acute infection is mostly atypical when compared to dogs, and due to difficulties to define an archetypal clinical presentation in cats, feline leptospirosis is likely to be underdiagnosed disease in this species.

Leptospirosis as a cause of infertility in Uruguayan beef cattle.

Leptospirosis, caused by pathogenic spirochetes of the genus Leptospira spp., is a globally significant zoonotic disease that affects humans and animals. In cattle, leptospirosis is associated not only with overt clinical manifestations but also with reproductive diseases, including infertility. This study assesses the potential correlation between leptospirosis and infertility in Uruguayan beef cattle. A case-control study involved 31 beef herds with no prior history of Leptospira vaccination. In each herd, veterinarians identified 10 non-pregnant (cases) and 25 pregnant cows (controls) using ultrasound, and blood and urine samples were collected from each cow. Serological diagnosis was performed using the Microscopic Agglutination Test (MAT), and quantitative PCR (qPCR) was used to assess Leptospira excretion. Additionally, antibodies against bovine viral diarrhea virus (BVDV) and infectious bovine rhinotracheitis (IBR) were tested. The results demonstrated an association between seropositivity to the Sejroe serogroup (cut-off 1:200) and infertility in cattle (OR=1.31; p-value=0.06). Furthermore, the level of Leptospira excretion (qPCR) in urine was associated with increased infertility risk, with cows excreting over 100 copies per mL of urine having the highest odds of infertility (OR=2.34; p-value<0.01). This study suggests a potential association between leptospirosis and infertility in Uruguayan beef cattle, emphasizing the importance of both serological and molecular diagnostics for assessing reproductive health in cattle herds. Future research should explore the impact of Leptospira serogroups on other reproductive disorders in cattle.

Genital route in experimental infection, a promising approach to study genital leptospirosis in ruminants.

Infection by Leptospira sp., mainly strains from the Sejroe serogroup, impairs the reproductive efficiency of ruminants leading to economic losses. Although the majority of experimental studies use the intraperitoneal route of leptospiral infection, it has been suggested that natural infection occurs frequently by sexual transmission. Thus, we assessed the genital route of infection to study genital leptospirosis in the sheep model. A strain of L. borgpetersenii serogroup Sejroe, serovar Hardjobovis was inoculated in 18 ewes, divided into three groups for inoculation: intraperitoneal (n=6; Gip), cervical superficial (genital) (n=6; Ggen) and conjunctival (n=6; Gconj). Monthly, for 90 days, blood samples were collected for serology (MAT) and PCR was performed on urine, cervical-vaginal mucus, and uterine fragments. All ewes were successfully infected, independently of the infection route. Gip and Ggen did not differ throughout the experiment, either on seroconversion or on PCR positivity on urine or genital samples. In contrast, Gconj presented fewer seroreactive animals (P<0.05) and fewer PCR-pos on genital samples than the other groups. The results obtained demonstrated that, although all groups presented both urinary and genital infections, the genital route was more efficient and did not differ from the traditional intraperitoneal. It indicates that genital via, besides being a naturally occurring transmission via, represents a promising and interesting route regarding future studies related to genital leptospirosis in ruminants, and its use should be encouraged.

The presence of Leptospira spp. in the follicular fluid of naturally infected cows affects the overall efficiency of the in vitro embryo production technique.

The relationship between Leptospira infection and reproductive failures, as well as the mechanisms that lead to it, has not yet been fully established. It has been hypothesized that the presence of Leptospira spp. in the follicular fluid (FF) could impair the oocyte developmental competence. Thus, the impact of the presence of Leptospira spp. in the FF on in vitro embryo production (IVEP) outcomes was assessed. Dairy cows (n=244) from different farms were subjected to ovum pick-up for cumulus-oocyte complexes (COCs) collection. After PCR analysis of the FF, cows were retrospectively allocated into either: positive (POS-FF) or negative (NEG-FF) group. Statistical modeling was conducted using the farm, PCR result, and laboratory in which the IVEP was performed as effects. Noteworthy, 26.6% of the animals were positive for Leptospira spp., and 70% of farms had at least one POS-FF cow in the herd. POS-FF cows had a lower number of COCs recovered (22.6 ± 1.2 vs 15.0 ± 2.8, P=0.036), rate of viable COCs (85.6 ± 0.9% vs 78.1 ± 2.8%, P=0.015), number of good-quality COCs (16.0 ± 0.9 vs 9.8 ± 2.1, P=0.026), cleaved embryos (11.9 ± 0.7 vs 7.5 ± 1.5, P=0.032), and blastocysts (7.3 ± 0.4 vs 2.3 ± 0.7, P=0.044) yielded per cow. In conclusion, the presence of Leptospira spp. in the FF of naturally infected cows impaired the amount of COCs recovered, decreasing the overall IVEP efficiency.

Placental abnormalities associated with Leptospira interrogans infection in naturally infected mares.

The reproductive features of equine leptospirosis are often neglected. Equine genital leptospirosis is characterized as a silent chronic syndrome, and besides abortions, leads to placental abnormalities, stillbirths, and birth of weak foals. This study aimed to study the occurrence of placental abnormalities associated with Leptospira interrogans infection in naturally infected mares under field conditions. The studied herd had a high occurrence of placentitis and abortions. Ten pregnant mares, eight with placental abnormalities on ultrasonography and were selected. Serum and cervicovaginal mucus (CVM) samples were collected for serology and PCR, respectively. Positive samples in lipL32-PCR were submitted to the sequencing of the secY gene. In lipL32-PCR of CVM, five out of 10 (50%) mares were positive and all were characterized as Leptospira interrogans. Our results highlight the presence of placental abnormalities in the reproductive subclinical leptospirosis syndrome. We encourage field veterinarians to include leptospirosis testing in their reproductive management.

Isolation and molecular identification of Leptospira santarosai and Leptospira interrogans in equines from eastern Mexico.

Leptospirosis is an infectious disease with a worldwide distribution, which represents a major challenge in animal production across developing countries, mainly in tropical areas. Horses are particularly susceptible to the disease, presenting manifestations ranging from subclinical to the development of uveitis that compromises the visual health of the animals. In recent years, serological studies have been carried out in equid populations from America, demonstrating high exposure. For this reason, the aim of this study was to demonstrate microbiologically and molecularly the presence of the members of the genus Leptospira in urine samples from equids in an endemic state of leptospirosis in Mexico, and to detect the serological presence of anti-Leptospira antibodies in the sampled animals. For this reason, blood and urine samples were collected from 28 horses and one mule from three localities in the state of Veracruz, Mexico. Urine samples were inoculated in Ellinghausen-McCullough-Johnson-Harris (EMJH) medium, and the recovered isolates were typed using a short Multi Locus Sequence Typing scheme. Amplifications of the expected size were subjected to sequencing, and the recovered sequences were compared with those of reference deposited in GenBank using the BLAST tool. To identify their phylogenetic position, we performed a phylogenetic reconstruction using the maximum likelihood method. Additionally, Microscopic Agglutination test was performed on the serum samples to identify anti-Leptospira antibodies. We recovered 16 urine isolates which tested positive for the presence of Leptospira DNA. The phylogenetic reconstruction and the MLST analysis confirmed the presence of several genotypes of Leptospira interrogans and Leptospira santarosai. An overall serological frequency of 97.1 % was detected. Our results represent the first record of the presence of Leptospira through bacteriological isolates in equids from Mexico.

Domestic dogs in indigenous Amazonian communities: Key players in Leptospira cycling and transmission?

BACKGROUND: Leptospirosis is the world's most common zoonotic disease. Mitigation and control rely on pathogen identification and understanding the roles of potential reservoirs in cycling and transmission. Underreporting and misdiagnosis obscure the magnitude of the problem and confound efforts to understand key epidemiological components. Difficulties in culturing hamper the use of serological diagnostics and delay the development of DNA detection methods. As a result, especially in complex ecosystems, we know very little about the importance of different mammalian host species in cycling and transmission to humans. METHODOLOGY/PRINCIPAL FINDINGS: We sampled dogs from five indigenous Kichwa communities living in the Yasuní National Park in the Ecuadorian Amazon basin. Blood and urine samples from domestic dogs were collected to assess the exposure of these animals to Leptospira and to identify the circulating species. Microscopic Agglutination Tests with a panel of 22 different serovars showed anti-leptospira antibodies in 36 sampled dogs (75%), and 7 serogroups were detected. Two DNA-based detection assays revealed pathogenic Leptospira DNA in 18 of 19 dog urine samples (94.7%). Amplicon sequencing and phylogenetic analysis of 16S rRNA and SecY genes from 15 urine samples revealed genetic diversity within two of three different Leptospira species: noguchii (n = 7), santarosai (n = 7), and interrogans (n = 1). CONCLUSIONS/SIGNIFICANCE: The high prevalence of antibodies and Leptospira DNA provides strong evidence for high rates of past and current infections. Such high prevalence has not been previously reported for dogs. These dogs live in the peridomestic environment in close contact with humans, yet they are free-ranging animals that interact with wildlife. This complex web of interactions may explain the diverse types of pathogenic Leptospira observed in this study. Our results suggest that domestic dogs are likely to play an important role in the cycling and transmission of Leptospira. Future studies in areas with complex ecoepidemiology will enable better parsing of the significance of genotypic, environmental, and host characteristics.

Seroprevalence of leptospirosis among stray dogs in Bosnia and Herzegovina.

Leptospirosis is a (re) emerging zoonosis that occurs worldwide. This study aimed to assess seroprevalence of leptospirosis and to identify the most common reactive serovars and risk factors for seropositivity in apparently healthy stray dogs of unknown vaccination status in the Sarajevo region of Bosnia and Herzegovina. Positive microscopic agglutination test titres (≥ 1:25) were detected in 3.87% (156/4028) of samples and most of the sera reacted against one serovar (85.9%). Dogs were most commonly reactive to Canicola (40.4%) and Hardjo (33.3%), followed by Pomona (15.4%) Tarassovi (14.7%), Icterohaemorrhagiae (8.3%), Grippotyphosa (5.8%), Bratislava (1.3%) and Saxkoebing (0.6%). Dogs older than one year had higher odds of seropositivity compared to younger dogs. The seropositivity was higher in spring and autumn than in summer. These results advocate for the need of a control strategy for this zoonosis in the country, which should include sero-surveillance, monitoring, and the inclusion of additional serovars in the testing.

The seasonality as a relevant aspect to be considered for differential diagnosis of Trypanosoma vivax infection and co-infections in female cattle.

Bovine Trypanosomiasis and other infectious diseases cause relevant loss for the livestock industry impacting productive/reproductive indices. This study intended to better understand the frequency, seasonality, and profile of infections associated with Bovine Trypanosomiasis. A total of 1443 serum samples were screened for T. vivax infection and other infectious diseases: Neosporosis, Leptospirosis, Bovine Leukosis Virus infection/(BLV), Infectious Bovine Rhinotracheitis/(IBR) or Bovine Viral Diarrhea/(BVD). Distinct methods were used for screening and diagnosis: immunofluorescence assay (Trypanosomiasis), ELISA (Neosporosis,BLV,IBR,BVD) and microscopic agglutination test (Leptospirosis). Our findings demonstrated that the seropositivity for Trypanosomiasis=57% was similar to Neosporosis=55%, higher than Leptospirosis=39% and BVL=34%, but lower than IBR=88% and BVD=71%. The seropositivity for Trypanosomiasis was higher in the autumn and lower in the winter. Regardless the season, the IBR seropositivity (min=73%;max=95%) was higher than Trypanosomiasis (min=48%;max=68%). Moreover, Neosporosis (min=71%;max=100%) and BVD (min=65%;max=76%) were more frequent than Trypanosomiasis in the summer, winter and spring. The diagnosis outcome revealed that Trypanosomiasis&IBR=43% and Trypanosomiasis&Neosporosis=35% were the most frequent co-infections with higher seropositivity in the autumn (58%) and summer (80%), respectively. Noteworthy, high seropositivity to Trypanosomiasis&BVD was registered in the autumn (46%). Together, our data re-enforce the relevance of differential diagnosis between Trypanosomiasis with other bovine infectious diseases and that differences in the seasonality profile is a relevant aspect to be considered while selecting the differential diagnosis to be applied.

LIC_12757 from the pathogenic spirochaete Leptospira interrogans encodes an autoregulated ECF σE-type factor.

ECF (extracytoplasmic function) σ factors, members of the σ70-family, are the largest class of alternative σ factors which are stimulated in the presence of specific signals and direct RNA polymerase to transcribe a defined subset of genes. Thanks to them, bacterial pathogens can effectively reprogram their gene expression and, consequently, survive in the host and establish infection in a relatively short time. The number of ECF σ factors encoded within bacterial genomes is different depending on a given species and it reflects the likelihood that these bacteria will encounter harsh environmental conditions. The genome of L. interrogans, a zoonotic pathogen responsible for leptospirosis, is predicted to encode 11 ECF σE-type factors, but none of them have been characterized biochemically to date and their functions are still unknown. Here, we focused on one of the leptospiral ECF σ factors, namely LIC_12757, which was previously found to be up-regulated at elevated temperatures and may be related to the expression of clpB encoding an important L. interrogans virulence factor. We report cloning of the coding sequence of the LIC_12757 gene, its expression with the pET system and biochemical characterization of LIC_12757. By performing EMSA and in vitro transcription assays, we provide strong evidence that LIC_12757 indeed functions as a transcriptional factor that enables RNA polymerase to bind to the specific σE-type promoter and to initiate transcription. Interestingly, we demonstrate that LIC_12757 is autoregulated at the transcriptional level. Our study is a first step towards determining key aspects of LIC_12757 function in pathogenic Leptospira.

Leptospira infection and carrier survey on rats from wet market areas in Kuala Lumpur, Malaysia.

BACKGROUND OBJECTIVES: Leptospirosis is an important zoonotic infection that has caused significant mortality and morbidity worldwide. This disease is endemic in Malaysia and as a developing tropical country, leptospirosis is concerning as it threatens Malaysian public health and the country's economic sectors. However, there is limited information on leptospirosis in Malaysia, especially regarding leptospiral seroepidemiology among carriers in Malaysia. Therefore, more epidemiological information on the source of the disease and reservoir are needed for better disease control and source intervention. The objectives of this study are to gather information on Leptospira infection and the carrier status of rats captured from selected wet markets of Kuala Lumpur metropolitan city in Malaysia. METHODS: Live rat trappings were performed in four major wet markets in Kuala Lumpur, namely, Pudu, Chow Kit, Datuk Keramat, and Petaling Street. Animal samplings were performed for 12 months in 2017, where blood and kidney samples were collected and tested for anti-leptospiral antibodies via Microscopic Agglutination Test (MAT) and pathogenic Leptospira screening via Polymerase Chain Reaction (PCR) amplification offlaB gene. RESULTS: MAT showed that 34.7% (n = 50/144) of the captured rats were positive for anti-leptospiral antibody of which the most prominent serovar was Malaya followed by a local strain, IMR LEP 175. In parallel, 50 rats were also positive for pathogenic Leptospira DNA. INTERPRETATION CONCLUSION: This study showed that there are persistent Leptospira infections among rats in Kuala Lumpur wet markets and these rats are important reservoir hosts for the bacteria.

Acute kidney injury and liver disease in an American bulldog with suspected leptospirosis.

A 6-year-old spayed female American bulldog was brought to a veterinary clinic with a 3-day history of vomiting, lethargy, anorexia, icterus, hemorrhagic diarrhea, and oliguria. The dog's clinical signs, complete blood (cell) count, serum biochemistry, urinalysis, and diagnostic imaging were indicative of acute kidney injury and acute hepatopathy consistent with leptospirosis. Treatment for leptospirosis was initiated but, due to the dog's lack of response and progression of clinical signs, euthanasia was ultimately elected after 3 d of hospitalization. The dog tested negative for Leptospira spp. on ELISA; urine, blood, and tissue PCRs; and immunohistochemistry. This case demonstrates that confirmation of leptospirosis can be challenging, even in an animal with the expected clinical presentation. Therefore, limitations of the diagnostic tests available, as well as the possibility of other, less likely differential diagnoses such as toxicosis, must be considered.

Lésion rénale aiguë et maladie hépatique chez un bouledogue américain avec leptospirose suspectée. Une femelle bouledogue américain stérilisée âgée de 6 ans a été présenté à une clinique vétérinaire avec une histoire d'une durée de 3 jours de vomissement, léthargie, anorexie, ictère, diarrhée hémorragique et oligurie. Les signes cliniques de la chienne, un comptage cellulaire sanguin complet, une biochimie sérique, une analyse d'urine et de l'imagerie diagnostique étaient indicateur de lésion rénale aiguë et d'hépatopathie aiguë compatibles avec la leptospirose. Un traitement pour la leptospirose a été instauré mais, étant donné l'absence de réponse de l'animal et la progression des signes cliniques, l'euthanasie a finalement été décidée après 3 jours d'hospitalisation. L'animal s'est avéré négatif par ELISA pour Leptospira spp.; l'urine, le sang et les tissus étaient également négatifs par PCR; et par immunohistochime. Ce cas illustre le fait que la confirmation de la leptospirose peut représenter un défi, même chez un animal avec la présentation clinique attendue. Ainsi, les limites des tests diagnostiques disponibles, de même que la possibilité d'autres diagnostics différentiels moins probables, tel qu'une toxicose, doivent être considérés.(Traduit par Dr Serge Messier).