Feral cats do not play a major role in leptospirosis epidemiology on Reunion Island

Investigation of anti-Leptospira spp. antibodies and leptospiruria in cats attended to a veterinary teaching hospital in southern Brazil

Leptospirosis is a bacterial zoonosis that affects both humans and animals worldwide. Currently, it is known that cats may be susceptible to infection. This study aims to investigate the presence of anti-Leptospira spp. antibodies and leptospiruria in cats, using Microscopic Agglutination Test (MAT) and Real-time Polymerase Chain Reaction (PCR) techniques, respectively. A total of 76 cats, undergoing comprehensive anamnesis, general physical examination, and complementary exams were included in the investigation. Among the 76 cats tested, 9.2% (7/76) exhibited the presence of anti-Leptospira spp. antibodies, while Leptospira spp. DNA was detected in at 1.3% (1/76) of the evaluated urine samples. No significant associations were observed between the serological and molecular diagnostic results and the assessed variables, including clinical data and laboratory results of cats testing positive. This study provides insight into the occurrence of Leptospira spp. infection and leptospiruria in cats treated at a veterinary teaching hospital in southern Brazil.

Feline leptospirosis prevalence worldwide: A systematic review and meta-analysis of diagnostic approaches

Background and Aim

Leptospirosis in felids (domestic and wild cats) presents an ongoing challenge in our understanding. Numerous studies have reported the detection of Leptospira spp. in these feline populations, highlighting their potential as zoonotic carriers. This systematic review and meta-analysis aimed to provide insight into the global prevalence of leptospirosis in domestic and wild cats.

Materials and Methods

We conducted extensive searches across five databases (PubMed, Scopus, Web of Science, Science Direct, and Google Scholar) following the Preferred Reporting Items for Systematic Reviews and Meta-analyses Protocols guidelines. Random-effect meta-analyses were performed using R software version 4.3.0 to estimate pooled prevalence rates. Subgroup meta-analyses were conducted based on continents, diagnostic methods, sample types, and wildcat genera.

Results

A total of 71 articles on leptospirosis in domestic cats and 23 articles on leptospirosis in wild cats met the eligibility criteria. Our findings indicated a significantly higher pooled seroprevalence of leptospirosis in domestic cats compared with infection prevalence (9.95% [95% confidence interval (CI), 7.60%-12.54%] vs. 4.62% [95% CI, 2.10%-7.83%], p = 0.01). In contrast, no significant difference was observed in pooled seroprevalence and infection prevalence among wild cats (13.38% [95% CI, 6.25%-21.93%] vs. 2.9% [95% CI, 0.00%-18.91%], p = 0.21). A subgroup meta-analysis of domestic cats revealed significant differences in seroprevalence across continents, sample types, and diagnostic methods. On the contrary, wild cats had no significant differences in any of the subgroups.

Conclusion

Leptospira spp. have evidently been exposed to both domestic and wild cats, highlighting their potential roles as reservoir hosts for leptospirosis. These findings highlight the importance of considering felids as a possible public health threat.

Evaluation of Leptospira infection and exposure in free-roaming cat populations in northern California and southern Texas

OBJECTIVES

Leptospirosis is a re-emergent zoonotic bacterial disease associated with renal and hepatic injury. In free-roaming cats in some regions, a high prevalence of Leptospira antibodies has been identified, and pathogenic leptospires have been detected in renal tissue, indicating that they may play a role in Leptospira epidemiology. The objective of this study was to determine the prevalence of Leptospira seroreactivity and urinary shedding of Leptospira DNA in free-roaming cats from northern California and southern Texas. A secondary objective was to compare the results of a point-of-care (POC) assay, designed to detect Leptospira antibodies, with the results of the microscopic agglutination test (MAT) when applied to serum samples from feral cats.

METHODS

Specimens were obtained from free-roaming cats from northern California (n = 52; 2020) and southern Texas (n = 75; 2017). Leptospira quantitative PCR was performed on blood and urine specimens from Californian cats. Serum samples from Californian and Texan cats were subjected to MAT to categorize them as Leptospira antibody-positive or antibody-negative. The performance of the POC assay was assessed using the MAT as the gold standard.

RESULTS

Leptospira DNA was not detected in the blood or urine of any cats tested. The results of the MAT were positive in 17.3% (n = 9) of Californian cats and 10.7% (n = 8) of Texan cats (P = 0.3). The median MAT titer was 1:100 (range 1:100-1:200) in Californian cats and 1:200 (range 1:100-1:800) in Texan cats. The POC assay was negative in all specimens.

CONCLUSIONS AND RELEVANCE

Free-roaming cats in California and Texas are exposed to Leptospira species and may have the potential to act as sentinel hosts. No cats had evidence of current infection, as determined using PCR on blood and urine specimens. The POC test did not reliably detect anti-Leptospira antibodies in these cats. The role of cats in the maintenance or shedding of pathogenic leptospires requires further investigation.

Leptospiral infection in domestic cats: Systematic review with meta-analysis

The role of domestic cats in the transmission of Leptospira is controversial, being considered either as a protective factor or a potential source of infection for humans. The aims of this study were to obtain an integrated estimate of the prevalence of leptospiral infection in domestic cats, and to characterize those individuals most susceptible to infection. For this systematic review and meta-analysis, five electronic databases, as well as the reference lists of eligible reports were screened for observational studies published during 1979-2022. The overall prevalence of leptospiral antibodies and of pathogenic Leptospira in kidney/urine was estimated using three-level meta-analysis models. To investigate potential sources of heterogeneity, moderator analyses was performed using the sampling year, health status, living environment, and origin of the cats. The odds-ratio (OR) of potential risk factors was estimated using random-effects meta-analysis models for binary outcomes. The literature search identified 61 eligible publications, containing 114 effect estimates. The overall seroprevalence was 11.7 % (95 % CI: 9.3-14.6 %), the prevalence of leptospires in urine was 3.7 % (95 % CI: 1.7-8.1 %), and the prevalence of leptospires in kidney tissue was 12.8 % (95 % CI: 3.2-39.9 %). There were no significant differences in the estimated prevalence after removing articles with medium risk of bias. Seroprevalence was higher in Europe when compared to Latin America and the Caribbean (P = 0.047) and showed a mild decrease over time (P = 0.023). Outdoor cats had almost three times greater probabilities of infection with Leptospira (OR: 2.74, 95 % CI: 1.10-6.84). No other significant effect was detected among the tested moderators or potential risk factors (P > 0.05). Results suggest that feline leptospirosis should receive particular attention in veterinary care, as exposure to leptospires can occur in approximately 1 in every 10 cats, and more frequently in cats with street access. Domestic cats should be considered as potential Leptospira carriers when designing public health strategies for the control and prevention of leptospirosis. Further investigation is required to improve knowledge of the role of these animals in the environmental transmission cycle.

Leptospira spp. Prevalence in Cats from Southern Italy with Evaluation of Risk Factors for Exposure and Clinical Findings in Infected Cats

Leptospirosis is a worldwide zoonotic disease, but feline leptospirosis is rarely reported. This study aimed at investigating Leptospira spp. prevalence in cats from southern Italy, evaluating risk factors, clinical findings and laboratory data associated with infection. The serum of 112 cats was investigated by microscopic agglutination test (MAT), detecting anti-Leptospira antibodies against 14 pathogenic serovars. Blood and urine samples were tested by a real-time polymerase chain reaction targeting the lipL32 gene of pathogenic Leptospira. Antibodies against serovars Poi, Bratislava, Arborea, Ballum, Pomona and Lora were detected in 15.3% (17/111) of cats (titers range: 20-320). Leptospira spp. DNA was found in 3% (4/109) of blood and 9% (10/111) of urine samples. The spring season was the only risk factor for urinary Leptospira DNA shedding. Laboratory abnormalities significantly associated and/or correlated with Leptospira spp. positivity were anemia, monocytosis, neutrophilia, eosinopenia, increased alanine aminotransferase activity, hypoalbuminemia and hyperglobulinemia. In the investigated areas, cats are frequently infected by Leptospira spp. and can represent an additional reservoir or sentinel for a risk of infection. Moreover, some laboratory changes could be compatible with a pathogenic effect of Leptospira spp. in the feline host.

Role of Diagnostics in Epidemiology, Management, Surveillance, and Control of Leptospirosis

A One Health approach to the epidemiology, management, surveillance, and control of leptospirosis relies on accessible and accurate diagnostics that can be applied to humans and companion animals and livestock. Diagnosis should be multifaceted and take into account exposure risk, clinical presentation, and multiple direct and/or indirect diagnostic approaches. Methods of direct detection of Leptospira spp. include culture, histopathology and immunostaining of tissues or clinical specimens, and nucleic acid amplification tests (NAATs). Indirect serologic methods to detect leptospiral antibodies include the microscopic agglutination test (MAT), the enzyme-linked immunosorbent assay (ELISA), and lateral flow methods. Rapid diagnostics that can be applied at the point-of-care; NAAT and lateral flow serologic tests are essential for management of acute infection and control of outbreaks. Culture is essential to an understanding of regional knowledge of circulating strains, and we discuss recent improvements in methods for cultivation, genomic sequencing, and serotyping. We review the limitations of NAATs, MAT, and other diagnostic approaches in the context of our expanding understanding of the diversity of pathogenic Leptospira spp. Novel approaches are needed, such as loop mediated isothermal amplification (LAMP) and clustered regularly interspaced short palindromic repeats (CRISPR)-based approaches to leptospiral nucleic acid detection.

Serologic and urinary survey of exposure to Leptospira species in a feral cat population of Prince Edward Island, Canada

OBJECTIVES

Recent studies show that cats could play an important role in the transmission of Leptospira species. There are few reports of leptospirosis on Prince Edward Island (PEI) and none in cats. The objective of this study was to determine the prevalence of serum antibodies against Leptospira serovars and of Leptospira DNA in the urine of a population of free-roaming cats.

METHODS

Paired blood and urine samples were collected from 200 cats brought to a trap-neuter-return program. Antibody titers against six Leptospira serovars (Bratislava, Canicola, Gryppotyphosa, Hardjo, Pomona, Icterohaemorrhagiae) were determined by microscopic agglutination test. PCR was performed on urine samples to identify urine shedding of Leptospira DNA.

RESULTS

Antibodies were detected in 20/200 cats (10%) for at least one serovar, with titers ranging from 1:50 to 1:6400 (all serovars tested, except Hardjo). Urine samples of 7/200 cats (3.5%) were PCR-positive.

CONCLUSIONS AND RELEVANCE

Feral cats in PEI had a higher than expected exposure to leptospirosis and can shed DNA from pathogenic Leptospira species in urine. Further studies are needed to determine the prevalence of exposure to leptospirosis in other species on PEI and the potential role of feral cats in transmission of the disease.

Molecular and serological epidemiology of Leptospira infection in cats in Okinawa Island, Japan

Leptospirosis is a zoonosis caused by pathogenic Leptospira spp. Cats have been reported to be infected with Leptospira spp. and shed the bacteria in the urine. However, the importance of cats as an infection source for humans remains unclear. In this study, Leptospira infection in cats in Okinawa Prefecture, Japan, where leptospirosis is endemic, was investigated by leptospiral antibody and DNA detection using microscopic agglutination test and nested PCR, respectively. Moreover, multilocus sequence typing (MLST) and whole genome sequencing (WGS) were conducted on the Leptospira borgpetersenii serogroup Javanica isolated from cats, black rats, a mongoose, and humans. Anti-Leptospira antibodies were detected in 16.6% (40/241) of the cats tested, and the predominant reactive serogroup was Javanica. The leptospiral flaB gene was detected in 7.1% (3/42) of cat urine samples, and their sequences were identical and identified as L. borgpetersenii. MLST and WGS revealed the genetic relatedness of L. borgpetersenii serogroup Javanica isolates. This study indicated that most seropositive cats had antibodies against the serogroup Javanica and that cats excreted L. borgpetersenii in the urine after infection. Further, genetic relatedness between cat and human isolates suggests that cats may be a maintenance host for L. borgpetersenii serogroup Javanica and a source for human infection.

An Observational Study of Human Leptospirosis in Seychelles

A 1-year population-based prospective study was launched in Seychelles, a country with one of the highest human incidence of leptospirosis worldwide, to describe the characteristic features of the epidemiology of the disease and highlight the most prominent risk factors. Diagnosis was based on the IgM enzyme-linked immunosorbent assay, microscopic agglutination test, and real-time PCR. A standardized questionnaire was administered to 219 patients aged ≥ 13 years consulting for acute febrile illness. The high incidence of leptospirosis in Seychelles was confirmed. The disease was particularly severe, as the case fatality rate was 11.8%. Leptospirosis was positively associated in univariate analysis with socio-professional and clinical variables including gardening/farming, oliguria, jaundice, conjunctivitis, history of hepatitis C virus infection, anemia, thrombocytopenia, and/or biological renal failure. Epidemiological analyses of the questionnaires highlighted a link of the disease with living in houses (versus apartment), the presence of animals around and in houses, gardening, and misuse of personal protective equipment. Multivariate analyses indicated that being a farmer/landscaper and having cattle and cats around the home are the most significant drivers of leptospirosis. Biological features most associated with leptospirosis were thrombocytopenia, leukocytosis, high values for renal function tests, and elevated total bilirubin. We report changes in behavior and exposure compared with data collected on leptospirosis 25 years ago, with indication that healthcare development has lowered case fatality. Continuous health education campaigns are recommended as well as further studies to clarify the epidemiology of human leptospirosis, especially the role of domestic animals.

Leptospira Detection in Cats in Spain by Serology and Molecular Techniques

Leptospirosis is the most neglected widespread zoonosis worldwide. In Spain, leptospirosis reports in people and animals have increased lately. Cats can become infected with Leptospira, as well as be chronic carriers. The aim of this study was to determine serological antibody prevalence against Leptospira sp., blood DNA, and shedding of DNA from pathogenic Leptospira species in the urine of cats in Spain. Microagglutination tests (MAT) and blood and urine TaqMan real-time polymerase chain reaction (PCR) were performed. Leptospira antibodies were detected in 10/244 cats; with 4.1% positive results (95% confidence interval (CI): 2.1-7.18%). Titers ranged from 1:20 to 1:320 (serovars Ballum; Bataviae; Bratislava; Cynopteri; Grippotyphosa Mandemakers; Grippotyphosa Moskva; Pomona; and Proechimys). The most common serovar was Cynopteri. Blood samples from 1/89 cats amplified for Leptospira DNA (1.12%; 95% CI: 0.05-5.41%). Urine samples from 4/232 cats amplified for Leptospira DNA (1.72%; 95% CI: 0.55-4.10%). In conclusion free-roaming cats in Spain can shed pathogenic Leptospira DNA in their urine and may be a source of human infection. Serovars not previously described in cats in Spain were detected; suggesting the presence of at least 4 different species of pathogenic leptospires in the country (L. borgpetersenii; L. interrogans; L. kirschneri; and L. noguchii).