Nationwide Exposure of U.S. Working Dogs to the Chagas Disease Parasite, Trypanosoma cruzi

Abstract

Trypanosoma cruzi is a zoonotic protozoan parasite vectored by triatomine insects that are endemic to the Americas, including the southern United States. Surveillance of domestic dogs for T. cruzi exposure allows for the determination of geographic regions of transmission that are relevant for human and animal health. The U.S. Department of Homeland Security (DHS) working dogs provide critical security and detection services across the country, and many train or work in the southern United States, where they are at risk for T. cruzi exposure. We sampled blood from 1,610 working dogs (predominantly Belgian Malinois, German shepherds, and Labrador retrievers) from six task forces (including the Transportation Security Administration, Customs and Border Protection, Secret Service, and more) and two canine training centers across 41 states from 2015 to 2018. Canine sera that were reactive on at least two independent serological assays were considered positive for anti-T.-cruzi antibodies. In addition, up to three independent polymerase chain reaction (PCR) assays were used to detect and type T. cruzi DNA. Overall seroprevalence was 7.5%, and four dogs (0.25%, n = 1,610) had detectable parasite DNA in the blood, comprising parasite discrete taxonomic units (DTUs) TcIV and a coinfection of TcI/TcIV. Dogs that worked within versus outside of the geographic range of established triatomines showed comparable seroprevalence (7.3% and 9.2%, respectively; P = 0.61). Determining the prevalence of T. cruzi in these working dogs and looking at spatially associated risk factors have practical implications for disease risk management and could assist with improved control measures to protect both animal and human health.

High variation in immune responses and parasite phenotypes in naturally acquired Trypanosoma cruzi infection in a captive non-human primate breeding colony in Texas, USA

“…T. cruzi and insect species that can vector the infection have likely been present in the USA for at least thousands of years [8] and occasional transmission to humans living exclusively in the USA has been documented [9][10][11][12]. In contrast to humans, domestic and other animals are quite frequently reported to acquire T. cruzi infection, almost certainly via infected insect vectors [13][14][15][16][17]. Included among the animals known to be commonly infected with T. cruzi in the USA are non-human primates maintained in breeding and research colonies and in zoological settings.…”

Demographics and travel history of imported and autochthonous cases of leishmaniosis in dogs in the United States and Canada, 2006 to 2019

“…Protozoal cross‐reactivity on serology, specifically with T. cruzi , was considered for dogs in the West South Central region where T. cruzi is known to be most common in the US 31‐33 . Two dogs from this region were L. infantum IFAT positive; stored whole blood was available for PCR on 1 of these 2 dogs.…”

“…foxhound (4/125; 3.2%), and unknown (7/125; 5.6%; T. cruzi is known to be most common in the US. [31][32][33] Necropsy with histopathology failed to identify an underlying cause.…”

High variation in immune responses and parasite phenotypes in naturally acquired Trypanosoma cruzi infection in a captive non-human primate breeding colony in Texas, USA

“…T. cruzi and insect species that can vector the infection have likely been present in the US for at least thousands of years [8] and occasional transmission to humans living exclusively in the US has been documented [9][10][11][12]. In contrast to humans, domestic and other animals are quite frequently reported to acquire T. cruzi infection, almost certainly via infected insect vectors [13][14][15][16][17]. Included among the animals known to be commonly infected with T. cruzi in the U.S. are non-human primates maintained in breeding and research colonies and in zoological settings.…”