Global importance: Leptospirosis is the most widespread zoonosis worldwide. Mammals (eg, rats, horses, cows, pigs, dogs, cats and aquatic species, such as sea lions and northern elephant seals) can all be infected by leptospires. Infection in animals occurs through contact with urine or water contaminated with the bacteria. In people, the disease is acquired mainly from animal sources or through recreational activities in contaminated water. Practical relevance: Literature on the clinical presentation of leptospirosis in cats is scarce, although it has been demonstrated that cats are susceptible to infection and are capable of developing antibodies. The prevalence of antileptospiral antibodies in cats varies from 4% to 33.3% depending on the geographical location. Urinary shedding of leptospires in naturally infected cats has been reported, with a prevalence of up to 68%. Infection in cats has been associated with the consumption of infected prey, especially rodents. Thus, outdoor cats have a higher risk of becoming infected. Clinical challenges: Clinical presentation of this disease in cats is rare and it is not known what role cats have in the transmission of leptospirosis. Ongoing work is needed to characterise feline leptospirosis. Audience: This review is aimed at all veterinarians, both general practitioners who deal with cats on a daily basis in private practice, as well as feline practitioners, since both groups face the challenge of diagnosing and treating infectious and zoonotic diseases. Evidence base: The current literature on leptospirosis in cats is reviewed. To date, few case reports have been published in the field, and information has mostly been extrapolated from infections in people and dogs. This review is expected to serve as a guide for the diagnosis and management of the disease in cats.

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).

Early detection and treatment of cases of Leishmania infantum infection are critical in controlling the spread of the disease in dogs. Several serological methods are available to support the diagnosis of canine leishmaniosis. The immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) are the main tests used by clinicians. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. Conversely, the presence of low antibody levels is not necessarily indicative of disease and may be more difficult to detect by serological tests. The aim of this study was to evaluate and compare the diagnostic performance of four commercially available serological tests, including ELISAs (CIVTEST® CANIS LEISHMANIA short and standard protocols), LEISHMANIA-ELISA DOG®, ELISA/S7® and MegaFLUO®LEISH IFAT, for the detection of specific antibodies against L. infantum antigens in dogs in different states of infection. Canine sera samples from seropositive sick infected dogs (n = 75), seropositive apparently healthy dogs (n = 48), and seronegative apparently healthy dogs from a high endemic area (Cadiz, n = 40) and seronegative apparently healthy dogs from very low endemic area of L. infantum infection (Asturias, n = 40) were classified based on the results of an in-house UAB ELISA as a reference test. The positive percent of agreement (PPA) and negative percent of agreement (NPA) observed for each test were as follows: CIVTEST® standard (93.4 %, 100 %) on 202 samples tested, CIVTEST® short (84.4 %, 100 %) on 202 samples tested, LEISHMANIA-ELISA DOG® (81.8 %, 72.2 %) on 138 samples tested, ELISA/S7® (34.8 %, 45 %) on 195 samples tested and MegaFLUO®LEISH IFAT (100 %, 100 %) on 203 samples tested, respectively. The accuracy was as follows: CIVTEST® standard (0.96), CIVTEST® short (0.91), LEISHMANIA-ELISA DOG® (0.77), ELISA/S7® (0.39), and MegaFLUO®LEISH IFAT (1). The Cohen´s Kappa index (K) from best to worst was: MegaFLUO®LEISH IFAT (K = 1), CIVTEST® standard (K = 0.92), CIVTEST® short (K=0.81), LEISHMANIA-ELISA DOG® (K =0.54), and ELISA/S7® (K=-0.19). Finally, the area under the receiver operating characteristic curve (AUC-ROC), in the ELISAs test, ordered from the maximum to the minimum value was: CIVTEST® short (1), CIVTEST® standard (0.99), LEISHMANIA-ELISA DOG® (0.87), and S7® (0.37). In conclusion, this study demonstrated that the diagnostic performance of the commercially available ELISA tests against L. infantum antigen can vary widely. Moreover, it highlights the fact that CIVTEST® CANIS LEISHMANIA is a reliable test to support the diagnosis of canine leishmaniosis in clinical settings.

Canine leishmaniosis (CanL) is a zoonotic disease caused by Leishmania infantum, where increased interferon-gamma (IFN-γ) levels are associated with controlling the infection and mild to moderate disease. Therefore, monitoring IFN-γ concentrations is essential for monitoring the immune responses in CanL. This study compared a faster, cost-effective IFN-γ release whole blood assay in tubes (WBA-T) with a standardized version (WBA-S) in 41 dogs at different states of L. infantum infection. WBA-T was performed at 24, 48, and 72 h of incubation with three conditions: blood, blood with L. infantum-soluble antigen (LSA), and blood with mitogen ConA. WBA-S was performed in plates, with blood diluted and incubated for five days using the same conditions. Supernatants (WBA-S) or plasma (WBA-T) were harvested for IFN-γ measurement by ELISA. No significant differences were observed in terms of IFN-γ concentration between WBA-T and WBA-S under LSA conditions. However, the 48 h incubation period during WBA-T showed the highest median of IFN-γ concentration compared to other incubation periods and WBA-S. The IFN-γ concentrations under ConA stimulation in WBA-S were significantly higher than in WBA-T at all incubation times studied. In conclusion, WBA-T stimulated with LSA at 48 h incubation time was shown to be the most appropriate for assessing IFN-γ production.

Background: Leptospirosis is a neglected but widespread zoonotic disease throughout the world. The vast majority of mammals are hosts of Leptospira spp., including domestic cats, species in which no consensus has been reached on the clinical presentation or diagnosis of the disease. The study of acute-phase proteins (APPs) and biomarkers of oxidative status would contribute to knowledge about the course of the disease in cats. In this report, we evaluated four APPs: Serum amyloid A-SAA, Haptoglobin–Hp, albumin and Paraoxonase 1-PON1 and the antioxidant response through Total Antioxidant Capacity-TAC, in 13 free-roaming cats naturally infected by pathogenic leptospires and 19 leptospires-free cats, through a Principal Component Analysis (PCA). Results: The PCA retained two principal components (PC1 and PC2), explaining 60.1% of the observed variability of the inflammatory proteins and the antioxidant TAC. PC1 was mainly associated with an inflammatory process, whereas PC2 correlated with the antioxidant status. The most contributing variables in PC1 where albumin (27.46%), SAA (24.71%), Hp (21.56%) and PON1 (20.69%). Variables with significant contribution to the PC2 were the antibody titre against Leptospira spp. (48.41%) and TAC (35.04%). Overall, the PCA revealed differences in inflammatory and antioxidant biomarkers in cats naturally infected with leptospires compared to leptospires-free cats.Conclusions: Increases in Serum SAA, Hp, and decreases in serum albumin concentrations and PON1 activity indicate an acute phase response in infected, DNA positive cats. Moreover, we found an increase in TAC serum concentrations indicating an antioxidant response in this infection, which was proportional to the antibody titre and not to the presence of bacterial DNA.

In reply to a comment, we want to mention that we consider this report significant in animal leptospirosis