Detection and modeling of anti- Leptospira IgG prevalence in cats from Lisbon area and its correlation to retroviral infections, lifestyle, clinical and hematologic changes

Joana Moreira da Silva; Sara Prata; Tiago Dias Domingues; Rodolfo Oliveira Leal; Telmo Nunes; Luís Tavares; Virgílio Almeida; Nuno Sepúlveda; Solange Gil

doi:10.1016/j.vas.2020.100144

Detection and modeling of anti- Leptospira IgG prevalence in cats from Lisbon area and its correlation to retroviral infections, lifestyle, clinical and hematologic changes

Vet Anim Sci. 2020 Oct 1:10:100144. doi: 10.1016/j.vas.2020.100144. eCollection 2020 Dec.

Authors

Affiliations

¹ CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal.
² CEAUL - Centro de Estatística e Aplicações, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
³ Department of Statistics and Operational Research (DEIO), Faculty of Sciences, University of Lisbon, Portugal.
⁴ Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom.

Abstract

Leptospirosis is a zoonosis of global importance caused by Leptospira species. Rodents are the main reservoirs, known to shed the bacteria in urine, thus contaminating water and soil and infecting other animals and people. Leptospirosis has been re-emerging in both developing and developed countries including Europe. It has been hypothesized that cats could be asymptomatic carriers of Leptospira. This study aims to evaluate cats' exposure to Leptospira in Lisbon, Portugal, by measuring IgG titres and correlating them with possible factors that may increase the risk of exposure in urban cats. Two hundred and forty-three samples were collected from the biobank. An ELISA test followed by a seroprevalence analysis using a finite mixture model was performed to detect and measure anti-Leptospira IgG antibodies titres. In parallel, a survey was conducted to identify possible risk factors for seropositivity. According to the ELISA test protocol, only twenty-three cats (9.5%; 95% CI =(6.1%;13.9%)) could be considered as seropositive to Leptospira antigens. However, when the same data were analysed by the best different mixture models, one hundred and forty-four cats (59.3%; 95%CI = (52.8%; 65.5%)) could be classified as intermediate and high antibody responders to Leptospira antigens. Seropositivity to Feline Immunodeficiency Virus infection (FIV) was found to be the only significant risk factor associated with anti-Leptospira IgG antibodies. In conclusion, the present studies raises the possibility of a higher exposure of cats to Leptospira than previously thought due to the identification of a subpopulation of cats with intermediate antibody levels.

Keywords: ALP, serum alkaline phosphatase; ALT, alanine aminotransferase; AST, aspartate aminotransferase; CBC, complete blood count; CKD, Chronic Kidney Disease; ELISA, enzyme-linked immunosorbent assay; FIV positive; FIV, Feline Immunodeficiency Virus infection; FeLV, Feline Leukemia Virus; Free-roaming cats; IDIU, Infectious Diseases Isolation Unit; IgG; IgG, Immunoglobulin G; Leptospirosis; MAT, microscopic agglutination tests; One Health; PAHO, Pan American Health organization; USG, Urine Specific Gravity; VTH, Veterinary Teaching Hospital; WHO, World Health organization.