High incidence of Trypanosoma cruzi infections in dogs directly detected through longitudinal tracking at 10 multi-dog kennels, Texas, USA.

Rachel E Busselman,Carolyn L Hodo,Alyssa C Meyers,Rachel Curtis-Robles,Sarah A Hamer,Italo B Zecca,Andres H Castro,Rebecca E Dowd,Ashley B Saunders,Lisa D Auckland

doi:10.1371/journal.pntd.0009935

Abstract

Canine Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is increasingly recognized as a health concern for dogs in the USA, and infected dogs may signal geographic regions of risk for human disease. Dogs living in multi-dog kennel environments (kennels with more than one dog) where triatomine vectors are endemic may be at high risk for infection. We monitored a cohort of 64 T. cruzi-infected and uninfected dogs across 10 kennels in Texas, USA, to characterize changes in infection status over one year. We used robust diagnostic criteria in which reactivity on multiple independent platforms was required to be considered positive. Among the 30 dogs enrolled as serologically- and/or PCR-positive, all but one dog showed sustained positive T. cruzi diagnostic results over time. Among the 34 dogs enrolled as serologically- and PCR-negative, 10 new T. cruzi infections were recorded over a 12-month period. The resulting incidence rate for dogs initially enrolled as T. cruzi-negative was 30.7 T. cruzi infections per 100 dogs per year. This study highlights the risk of T. cruzi infection to dogs in kennel environments. To protect both dog and human health, there is an urgent need to develop more integrated vector control methods as well as prophylactic and curative antiparasitic treatment options for T. cruzi infection in dogs.

Highlights

The protozoan parasite Trypanosoma cruzi, agent of Chagas disease, is a vector-borne zoonotic pathogen endemic to the Americas
Chagas disease is a deadly parasitic heart disease of humans, dogs, and other mammals that is spread by kissing bug vectors
We aimed to identify and enroll approximately two to four T. cruzi-infected and two to four T. cruzi-uninfected dogs at each kennel for longitudinal tracking at approximate 6-month intervals

Summary

Introduction

The protozoan parasite Trypanosoma cruzi, agent of Chagas disease, is a vector-borne zoonotic pathogen endemic to the Americas. Enzootic cycles of T. cruzi transmission have been documented in the southern USA, where opossums (Didelphis virginiana), woodrats (Neotoma spp.), coyotes (Canis latrans), and other mammals naturally infected with T. cruzi come into contact with endemic triatomine species [7,8,9] and maintain parasite transmission [1,10,11,12,13]. The wildlife species involved in the transmission of T. cruzi often inhabit peridomestic environments and share spaces with domestic dogs outdoors, increasing dogs’ risk of exposure to infected vectors [11,14]. In settings where dogs share spaces with humans in and around homes, dogs serve as sentinels for human infection, maintaining T. cruzi transmission and amplifying disease in domestic and peridomestic environments [15,16]. Areas of high T. cruzi seroprevalence in domestic dogs may indicate areas of heightened risk for human infection [17]

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