Prevalence and incidence of vector-borne pathogens in unprotected dogs in two Brazilian regions

Filipe Dantas-Torres,Lidiane Gomes Da Silva,Vitor Márcio Ribeiro,Joanna Lúcia De Almeida Alexandre,Guilherme Ribeiro Valle,Katrin Deuster,Matthias Pollmeier,Débora Elienai De Oliveira Miranda,Gertraut Altreuther,Luciana Aguiar Figueredo,Kamila Gaudêncio Da Silva Sales,Yury Yzabella Da Silva,Domenico Otranto

doi:10.1186/s13071-020-04056-8

Abstract

BackgroundVarious vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infection being usually higher in the tropics. Cross-sectional studies have been conducted to investigate the prevalence of VBPs in dogs, but data from longitudinal studies are scarce. Herein, we assessed the prevalence and the year-crude incidence (YCI) of Leishmania spp. and other VBPs in privately-owned dogs from two geographical regions of Brazil.MethodsA total of 823 dogs were initially screened for Leishmania spp. by both serology and polymerase chain reaction (PCR). From the negatives, 307 (103 from São Joaquim de Bicas, Minas Gerais, and 204 from Goiana, Pernambuco) were randomly selected for the longitudinal study. These dogs were tested for various VBPs at baseline, after 8 and 12 months.ResultsOut of 823 dogs initially screened, 131 (15.9%) were positive for Leishmania spp. Out of the 307 dogs enrolled in the longitudinal study, 120 (39.1%) were lost for different reasons (e.g. animal death, owner decision, and lost to follow-up). In São Joaquim de Bicas, the baseline prevalence and YCI were as follows: 16.5% and 7.1% for Anaplasma spp.; 81.6% and 100% for Babesia spp.; 0% and 1.3% (only one faint positive) for Dirofilaria immitis; 37.9% and 22.9% for Ehrlichia spp.; 19.5% and 43.8% for Leishmania spp. In Goiana, the baseline prevalence and YCI were as follows: 45.1% and 38.3% for Anaplasma spp.; 79.9% and 96.0% for Babesia spp.; 36.3% and 39.8% for D. immitis; 64.7% and 58.5% for Ehrlichia spp.; 14.7% and 19.6% for Leishmania spp. Anti-Borrelia burgdorferi antibodies were not detected in any of the samples tested herein. The prevalence and YCI of Anaplasma spp., D. immitis and Ehrlichia spp. were significantly higher in Goiana. In contrast, the YCI of Leishmania spp. infection was significantly higher in São Joaquim de Bicas.ConclusionsWe confirmed a high prevalence and YCI of various VBPs among privately-owned dogs in two geographical regions of Brazil. Our data also indicate that the risk of infection varies significantly for individual VBPs and between the regions, which may be related to several factors that are still poorly understood.

Highlights

Various vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infec‐ tion being usually higher in the tropics
Our previous study with a much smaller sample size suggested a higher prevalence of Leishmania spp. infection in dogs from São Joaquim de Bicas as compared to Goiana [19]
A previous study conducted in Natal (Rio Grande do Norte state, north-eastern Brazil) reported that higher owner education was associated with decreased levels of dog seropositivity to Leishmania spp

Summary

Introduction

Various vector-borne pathogens (VBPs) affect dogs worldwide, with their diversity and force of infec‐ tion being usually higher in the tropics. A wide range of vector-borne pathogens (VBPs), including bacteria, protozoa and filarial nematodes, can infect and eventually cause overt disease in domestic dogs worldwide [1,2,3,4]. These pathogens are transmitted to dogs, and eventually to other hosts, through various arthropod vectors, such as ticks, mosquitoes, phlebotomine sand flies, fleas, lice, and triatomine bugs [5]. Dogs living in Brazil are afflicted by numerous VBPs such as Babesia vogeli, Dirofilaria immitis, Ehrlichia canis and Leishmania infantum [7] They are affected by pathogens that are restricted to Latin America, including Leishmania amazonensis, Leishmania braziliensis and Rangelia vitalii [7]

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Conclusion