The aim of this systematic review was to investigate the prevalence of leptospirosis among stray and sheltered dogs worldwide. Six databases were searched, which resulted in the retrieval of 476 articles. Sixty articles were selected for analysis according to 10 quality criteria. Among the selected papers, 26 papers [43.4% (26/60)] met five of the 10 quality criteria established, 10 papers [16.7% (10/60)] met three criteria, nine papers [15.0% (9/60)] met four criteria, six papers [10.0% (6/60)] met six criteria, four papers [6.7% (4/60)] met eight criteria, and three papers [5.0% (3/60)] met nine of the 10 criteria, whereas two papers [1.7% (1/60)] met two and seven [1.7% (1/60)] criteria. Publications originated mainly from the Americas [45.0% (27/60)] and in the last 16 years (2003–2019) [81.7% (49/60)], and most of the sampled dogs were stray dogs [65.0% (39/60)]. The most commonly used diagnostic test for leptospirosis was the microscopic agglutination test [78.4% (47/60)] followed by polymerase chain reaction [21.7% (13/60)], and the most common serovars were Canicola [71.4% (35/49)], Icterohaemorrhagiae [65.3% (32/49)], Grippotyphosa [40.8% (20/49)], and Pomona [40.8% (20/49)]. In conclusion, our results showed that Leptospira spp. are present in unowned dogs worldwide; however, the low-methodological quality of the recovered cross-sectional studies precluded a meta-analysis.

A previously healthy 15-year-old teenage boy was admitted for fever and heart failure. Myocarditis was suspected, and endomyocardial biopsy revealed giant cell myocarditis. Immunosuppressive treatment was initiated, with excellent response. A plausible link to previous leptospirosis was identified. At 18-month follow-up, left ventricular function is normal. Only one other reported case of paediatric giant cell myocarditis had such a favourable outcome.

Although previous studies have reported Leptospira carriage in kidneys and urine of cats, the role of these animals in leptospirosis epidemiology remains poorly understood. Using molecular methods, we investigated Leptospira renal carriage in 172 feral cats from Reunion Island, an oceanic geographically isolated island located in the South West Indian Ocean. Only one out of the 172 analysed specimens tested positive for Leptospira DNA through quantitative real-time polymerase chain reaction. Using this positive sample, we could obtain sequences at three Leptospira loci (rrs2, lipL32 and lipL41) allowing to report for the first time Leptospira borgpetersenii naturally infecting cats. Comparisons with bacterial sequences from both acute human cases and animal reservoirs revealed similarities with Leptospira sequences previously reported on Reunion Island. However, the low prevalence (0.6%) reported herein does not support any major role of feral cats in leptospirosis epidemiology on Reunion Island, contrasting with results recently reported on another Indian Ocean Island, Christmas Island. The significance of these discrepancies is discussed.

Leptospirosis is a worldwide zoonotic disease determined by pathogenic spirochetes of the genus Leptospira. The control of bovine leptospirosis involves several measures including antibiotic treatment of carriers. Despite its importance, few studies regarding antimicrobial susceptibility of strains from bovine origin have been conducted. The aim of this study was to determine the in vitro susceptibility of Leptospira strains obtained from cattle in Rio de Janeiro, Brazil, against the main antibiotics used in bovine veterinary practice. A total of 23 Leptospira spp. strains were investigated for minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) using broth macrodilution. At the species level, there were not differences in MIC susceptibility except for tetracycline (P < 0.05). Nevertheless, at the serogroup level, differences in MIC were observed among Sejroe strains, mainly for ceftiofur, doxycycline and in MBC for streptomycin (P < 0.05). One strain presented MBC values above maximum plasmatic concentration described for streptomycin and was classified as presenting reduced susceptibility. Efficacy of antimicrobial therapy on bovine leptospirosis could be compromised due to occurrence of infection by Leptospira strains presenting reduced susceptibility.

Leptospirosis is a zoonotic bacterial disease of global importance. A large spectrum of asymptomatic animal hosts can carry the infection and contribute to the burden of human disease. Environmental sources of human contamination also point to the importance of a hydrotelluric reservoir. Leptospirosis can be caused by as many as 15 different pathogenic or intermediate Leptospira species. However, classification of these bacteria remains complicated through the use of both serological and genetic classification systems that show poor correlation. With the advent of molecular techniques, DNA-based barcoding offers a conceptual framework that can be used for leptospirosis surveillance as well as source tracking. In this review, we summarize some of the current techniques, highlight significant successes and weaknesses and point to the future opportunities and challenges to successfully establish a widely applicable barcoding scheme for Leptospira.

Asymptomatic dogs can be potential hosts of leptospirosis. However, the extension of this phenomenon in endemic areas has not yet been clearly defined. This study is aimed at evaluating the role of asymptomatic dogs as carriers of Leptospira in an endemic area of Brazil. A total of 131 male dogs without apparent leptospirosis symptoms were included in the study based on clinical and hematologic exams. Serum and urine samples were collected for microscopic agglutination tests (MAT) and polymerase chain reactions (PCR) targeted the LipL32 gene, respectively. Forty-two dogs (32·1%) presented seroreactivity (titres ⩾100). The serogroup Icterohaemorrhagiae was predominant, representing 92·7% of the seropositive samples. Overall, leptospiral DNA was detected on 26 urine samples (19·8%). PCR positivity was more common (28·6%) on seropositive dogs than on seronegative (15·7%) ones. Nevertheless, MAT was not correlated to PCR (P > 0·05). Age was not associated with seroreactivity, but dogs older than 5 years of age had 4·07 more chances (odds ratio) of being carriers (PCR positive) than younger ones. Although the fact of knowing that asymptomatic dogs can act as leptospiral carriers is not new, the extension of this fact is impressive in an endemic region, and its role and impact on public health cannot be neglected.

Leptospirosis is the most widespread zoonosis in humans worldwide. In the United States, widespread detection of antibodies to leptospirosis have been identified in feral swine (Sus scrofa) with the highest detection of serovars, Bratislava, Icterohaemorrhagiae, and Pomona. Over the past few years, feral swine populations have expanded their geographical range and distribution in the United States with reports in at least 39 of 50 states. Since feral swine serve as reservoirs for serovars that can infect humans, it is important to understand the risk of transmission. In order to learn more about the probability that feral swine shed infectious leptospires, we collected kidneys and paired serum when possible from 677 feral swine in 124 counties of 29 states. These counties had previously been identified as antibody positive for Leptospira interrogans serovars Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae or Pomona. Although exposure to these same six serovars of leptospirosis continued to be high (53% overall) in the counties we sampled, we detected leptospiral DNA in only 3·4% of feral swine kidneys tested. Based on these results, it appears that although feral swine can serve as a source of infection to humans, especially in those who are more likely to encounter them directly such as wildlife biologists, veterinarians, and hunters, the risk may be relatively low. However, further studies to examine the relationship between leptospiral shedding in the urine and kidneys in addition to culturing the organism are recommended in order to better understand the risk associated with feral swine.

The aim of this study was to identify Leptospira in urine samples of cattle by direct sequencing of the secY gene. The validity of this approach was assessed using ten Leptospira strains obtained from cattle in Brazil and 77 DNA samples previously extracted from cattle urine, that were positive by PCR for the genus-specific lipL32 gene of Leptospira. Direct sequencing identified 24 (31·1%) interpretable secY sequences and these were identical to those obtained from direct DNA sequencing of the urine samples from which they were recovered. Phylogenetic analyses identified four species: L. interrogans, L. borgpetersenii, L. noguchii, and L. santarosai with the most prevalent genotypes being associated with L. borgpetersenii. While direct sequencing cannot, as yet, replace culturing of leptospires, it is a valid additional tool for epidemiological studies. An unexpected finding from this study was the genetic diversity of Leptospira infecting Brazilian cattle.

Leptospirosis is a zoonosis of worldwide distribution, caused by infection with pathogenic spirochaetes of the genus Leptospira. The wild boar (Sus scrofa), an important hunting species in Europe, seems to play a significant role in the epidemiological cycle of leptospirosis. A total of 101 serum samples from wild boar hunted in Northern Portugal were analysed for leptospiral antibodies detection by microscopic agglutination test. Sera were collected during hunting seasons (2011–2013) and tested with 17 different pathogenic serovars of Leptospira. Antibodies against nine serovars were detected in 66 (65·4%) of these sera. Serovars Tarassovi and Altodouro exhibited the highest seroreactivity rates (23·8% and 16·8%, respectively), followed by Autumnalis (7·9%) and Bratislava (6·9%). Age and district of origin were found to be risk factors for the presence of leptospiral antibodies in contrast to gender. From a One Health perspective, this study revealed that wild boar should be considered as a potential source of leptospirosis dissemination for humans and animal species (domestic and wild) in shared environments, particularly in the Trás-os-Montes region.

As feral swine continue to expand their geographical range and distribution across the United States, their involvement in crop damage, livestock predation, and pathogen transmission is likely to increase. Despite the relatively recent discovery of feral swine involvement in the aetiology of a variety of pathogens, their propensity to transmit and carry a wide variety of pathogens is disconcerting. We examined sera from 2055 feral swine for antibody presence to six serovars of Leptospira that can also infect humans, livestock or domestic animals. About 13% of all samples tested positive for at least one serovar, suggesting that Leptospira infection is common in feral swine. Further studies to identify the proportion of actively infected animals are needed to more fully understand the risk they pose.

A total of 855 sera from dogs in Greece were tested for antibodies to strains belonging to the Pomona, Grippotyphosa and Australis serogroups of Leptospira to assess exposure levels to these serogroups, possible associations with clinical disease and to evaluate whether these findings support the inclusion of additional serovars in dog vaccines. Antibodies were detected in 110 (12·9%) dogs. The highest seroprevalence (4·9%) was to the proposed novel serovar Altodouro belonging to the Pomona serogroup. This serovar also showed a statistically significant association with clinical disease. Serovar Bratislava antibodies were found in 3·4% of sera. Consideration should be given to the inclusion of serovars belonging to the Pomona serogroup and serovar Bratislava in future dog vaccines for the Greek market.