Spatial and Simultaneous Seroprevalence of Anti-Leptospira Antibodies in Owners and Their Domiciled Dogs in a Major City of Southern Brazil.

Aline Do Nascimento Benitez,Renato Barbosa Reis,Federico Costa,Elsio Wunder,Roberta Lemos Freire,Thais Cabral Monica,Italmar Teodorico Navarro,Regina Mitsuka-Breganó,Lucienne Garcia Pretto Giordano,Jancarlo Ferreira Gomes,Micheline Sahyun Romanelli,Camila Marinelli Martins,Ana Carolina Miura,Alexander Welker Biondo,Isabela Machado Serrano,Albert Icksang Ko,Thiago Henrique Carneiro Rios Lopes

doi:10.3389/fvets.2020.580400

Abstract

Although leptospirosis has been considered a major concern in urban areas, no study to date has spatially and simultaneously compared both owner and dog serology in households of major cities. Accordingly, the aim of the present study was to assess the seroprevalence of Leptospira antibodies, evaluate associated risk factors and conduct spatial analyses in 565 randomly selected households, which included 597 dog owners and 729 dogs in Londrina, Southern Brazil. Seropositivity by MAT were detected in in 11/597 (1.84%) owners and in 155/729 (21.26%) dogs. The risk factors were evaluated with logistic regression analysis and spatial factors and case distribution were evaluated with kernel density analyses. The sera of 14/155 (9.03%) dogs reacted for more than one serovar with the same titer. Canicola was the most frequent serogroup, detected in 3/11 (27.27%) owners and 76/155 (49.03%) dogs. The highest titer among the owners was 1:3,200 and was detected in the same household with a titer of 1:800 in the dog. Simultaneous owner-dog seropositivity was found in 7/565 (1.23%) households, with three reacted against serogroup Canicola. Positive owners were detected in 4/565 (0.70%) households and positive dogs were detected in 141/565 (24.95%) households. The associated risks of infection for dogs were different from those associated with infection in owners. Risk analyses for Canicola also identified specific factors of infection. Regardless of owner and dog cases were not statistically clustered, the kernel map has shown dog positivity occurrence in the same hot locations and near positive owners. The dependent variable analysis and logit model suggested a greater likelihood of peri-domiciliary contact with Leptospira. In conclusion, exposure to Leptospira infection was significantly higher in dogs than in their owners and human cases spatially overlapped dog cases, implicating dogs as potential environmental sentinels for this disease. In addition, the associated risk may vary according to serogroup, and the observed simultaneous Canicola seropositivity of owner and dog has suggested intradomicile-transmitted infection.

Highlights

Leptospirosis has been considered a worldwide emerging infectious and zoonotic disease caused by the spirochete Leptospira spp., which may persist for months in moist soil and water associated with the presence of reservoir animals in nature and accidentally transmitted to human beings [1]
Another systematic review with studies on leptospirosis incidence from 34 countries estimate that 1.03 million human cases and 58,900 deaths due to the disease have been reported annually, mostly concentrated in slums and other poor urban areas of developing countries [8]
The aim of the present study was to assess the leptospirosis seroprevalence, the associated risk factors and conduct a spatial analysis in owners, dogs, and their respective households randomly selected of Londrina, a seat city of halfmillion people in Southern Brazil, which is nationally ranked 38th in population and 145th in human development index (HDI) out a total of 5,570 Brazilian cities

Summary

Introduction

Leptospirosis has been considered a worldwide emerging infectious and zoonotic disease caused by the spirochete Leptospira spp., which may persist for months in moist soil and water associated with the presence of reservoir animals in nature and accidentally transmitted to human beings [1]. Another systematic review with studies on leptospirosis incidence from 34 countries estimate that 1.03 million human cases and 58,900 deaths due to the disease have been reported annually, mostly concentrated in slums and other poor urban areas of developing countries [8]. Disease endemicity and increased incidence have been mainly located in the Caribbean and Latin America, as well as in Southeast Asia and Oceania [9], despite leptospirosis has been considered endemic (restricted or peculiar to a locality or region) in other areas as well where flooding and other environmental conditions associated with rodent infestation may favor the Leptospira life cycle [10]

Objectives

Methods

Results