Leptospira spp. in Cats in Estonia: Seroprevalence and Risk Factors for Seropositivity

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.

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.

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.

Feline Susceptibility to Leptospirosis and Presence of Immunosuppressive Co-Morbidities: First European Report of L. interrogans Serogroup Australis Sequence Type 24 in a Cat and Survey of Leptospira Exposure in Outdoor Cats

Leptospirosis is one of the most widespread zoonotic diseases and can infect both humans and animals worldwide. The role of the cat as a susceptible host and potential environmental reservoir of Leptospira is still not well understood, due to the lack of obvious clinical signs associated with Leptospira spp. infection in this species. This study aims to describe the first European detection of Leptospira interrogans serogroup Australis ST 24 in a young outdoor cat with a severe comorbidity (feline panleukopenia virus). In addition, the results of a preliminary study conducted in 2014-2016 are presented (RC IZSVE 16/12), which reports an investigation of Leptospira exposure of outdoor cats in Northeast Italy by means of serological investigation and molecular evaluation of urine. The animals included in the survey are part of samples collected during active and passive surveillance (diagnostic samples). The study reported a seroprevalence of 10.5% among outdoor cats and the serogroups identified were Grippotyphosa, Icterohaemorrhagiae, Bratislava, Canicola and Ballum. Symptomatic cats reported high MAT titres (ranging from 1:800 to 1:1600) towards antigens belonging to the serovars Grippotyphosa (1:800), Bratislava (1:1600), Icterohaemorrhagiae (1:200) and Copenhageni (1:200-1:800). In one subject, urine tested positive for Leptospira PCR. Cats with high antibody titres for Leptospira and/or positivity on molecular test suffered from immunosuppressive comorbidities (feline immunodeficiency virus and feline leukaemia virus; feline herpesvirus and lymphoma; hyperthyroidism). The overall prevalence of serum antibodies against Leptospira found in free-ranging cats (10.53%, 95% CI: 4.35-16.70%) and the identification of L. interrogans ST 24 in a young cat with immunosuppressive disease (feline panleukopenia virus) suggest the possibility of natural resistance to clinical leptospirosis in healthy cats. In a One Health perspective, further studies are needed to better define the pathogenesis of leptospirosis in cats and their epidemiological role as environmental sentinels or possible carriers of pathogenic Leptospira.

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.