Detection of Trypansoma cruzi in Kissing Bugs (Hemiptera: Reduviidae: Triatominae) Collected Across Oklahoma

Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) in the Midwest: prevalence among vectors and medical provider awareness

True bugs of the subfamily Triatominae may carry the protozoan Trypanosoma cruzi, the causative agent of Chagas disease. Endemic to South and Central America, the protozoan has been found in triatomines throughout the southern United States of America, yet it is unclear how far north Trypanosoma cruzi occurs in Triatoma species. The objective of this research was to determine if triatomines in the St. Louis metropolitan area carry this protozoan and to assess professionals across the One Health spectrum for knowledge of the vectors and Chagas disease. Triatomine bugs were collected using a variety of methods, and then processed using PCR and gel electrophoresis to determine if they were positive for Trypanosoma cruzi. In addition, a phone call survey measured knowledge of Chagas disease. Eleven Triatoma sanguisuga and one Triatoma lecticularia specimens were collected between July 2022 and October 2023. One triatomine collected was too desiccated to determine the species. Of the thirteen total specimens, 6 (46%) were positive for T. cruzi. The phone call survey yielded a response rate of 81% among 97 attempted calls. The professionals interviewed included 23 veterinarians, 19 pharmacists, 14 vector control specialists, 11 public health officials, 9 physicians, and 3 wildlife biologists. Of the 79 participants, 64% were unfamiliar with Chagas disease. This preliminary study showed that T. cruzi is prevalent among triatomines in the Midwest and that education across the One Health professional spectrum may increase knowledge among professionals.

Prevalence and Diversity of Trypanosoma cruzi in Triatomine Vectors and Their Blood Meal Sources from South Central Texas, USA

The prevalence of Trypanosoma cruzi was assessed in 117 triatomine insects from central Texas. The qPCR-based results revealed T. cruzi in 59% of the insects (62 adults and eight nymphs), with overall prevalences of T. cruzi of 0% (0/9), 64% (11/17), 58% (10/17), 73% (30/41), and 57% (19/33) for the Bastrop, Caldwell, Gonzales, Guadalupe, and Hays counties, respectively. Analyses of 18S rRNA fragments confirmed T. cuzi in 81% of these samples. Vectors were identified as Triatoma gerstaeckeri (35% of which 65% were positive for T. cruzi), T. sanguisuga (21%, 43% positive), and Paratriatoma leticularia (0.3%, 100% positive). Food sources were recovered from 29% of the insects. Raccoons were 53% of the blood meals (83% positive for T. cruzi), while the remainder came from a variety of sources, including humans (33% positive), house geckos, Eastern woodrats, plain-bellied water snakes (50% positive), hispid cotton rats (0% positive), chickens (100% positive); Asian forest turtles, bison, and pigs (0% positive). The serendipitous detection of blood meal sources at known minimum distances from the collection of the vector insect enabled us to provide several instances where the insect foraging distance was greater than 400 m. These vector foraging distances are novel information that can assist in our understanding of the landscape dynamics for the spread of the pathogen.

Detection of Bartonella in kissing bugs Triatoma rubrofasciata collected from Huizhou City, South China

Background

The blood-feeding behavior of kissing bugs (subfamily Triatominae, family Reduviidae, order Hemiptera) means they are potential vectors of multiple humans pathogens. However, investigations of vector-borne pathogens harbored by kissing bugs are rare.

Methods

In the current study, 22 adult kissing bugs (Triatoma rubrofasciata) were captured in Huizhou City, Guangdong Province, south China. The presence of vector-borne pathogens in the kissing bugs was tested, and the genetic diversity of these potential pathogens was investigated.

Results

All the kissing bugs were negative for Anaplasmataceae bacteria, Rickettsia, and Coxiella. Bartonella DNA was detected in 36.4% (8/22) of the kissing bugs. The sequences of the Bartonella gltA genes divided into two clades in a phylogenetic tree, with close relationships to B. tribocorum and uncultured Bartonella sp. clone MYR-283, respectively. All the groEL sequences were closely related to those of B. kosoyi (identity 98.75%-100%). The ftsZ and rpoB sequences were most closely related to those of B. elizabethae, a recognized human pathogen, with nucleotide similarities of 98.70%-100% and 99.45%-100%, respectively.

Conclusions

We report the detection of Bartonella DNA in Triatoma kissing bugs in southern China. Although the sample size is limited, the high positive rate of detection of Bartonella DNA, the close relationship of the gene sequences to those of zoonotic Bartonella species, and the distribution of the kissing bugs near human residences, hint at a risk to public health.

Chagas disease in Oklahoma

Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, is one of the leading public health problems in the Western Hemisphere. The parasite is mainly transmitted by contact with infected insect vectors but other forms of transmission are important in endemic areas. In the United States, while the disease is largely restricted to immigrants from endemic countries in Latin America, there is some risk of local acquisition. T. cruzi circulates in a sylvatic cycle between mammals and local triatomine insects in the southern half of the country, where human residents may be at risk for incidental infection. There are several reported cases of locally-acquired Chagas disease in the United States, but there is a paucity of information in Oklahoma. We present a brief summary of the available data of Chagas disease in Oklahoma to raise awareness and serve as a foundation for future research.

Trypanosoma cruzi and Other Vector-Borne Infections in Shelter Dogs in Two Counties of Oklahoma, United States

Trypanosoma cruzi is an emerging zoonotic vector-borne parasite infecting dogs and other mammals in the United States. In this study we evaluated shelter dogs in one northeastern and one southeastern county in Oklahoma for prevalence of exposure to T. cruzi. Dogs were tested for antibodies against T. cruzi using the Chagas STAT PAK^® assay and for T. cruzi in circulation by PCR. In addition, dogs were tested for evidence of infection with other vector-borne organisms using the SNAP^® 4Dx^® Plus Test and PCR. Overall, 26 of 197 (13.2%) shelter dogs had detectable antibodies against T. cruzi and 3 of 189 (1.6%) dogs were PCR positive. In addition, we found that 42 of 197 (21.3%) shelter dogs had evidence of exposure to or were infected with at least one vector-borne agent other than T. cruzi based on serology and/or PCR; 9 of 42 (21.4%) of these dogs were also positive for T. cruzi antibodies. Other infections identified in dogs included Anaplasma phagocytophilum, Anaplasma platys, Babesia sp. (Coco), Dirofilaria immitis, Ehrlichia canis, Ehrlichia chaffeensis, Ehrlichia ewingii, and Hepatozoon americanum. This study serves to boost state-wide veterinary and public health awareness of T. cruzi and other vector-borne pathogens infecting shelter dogs in Oklahoma. Results indicate the need for more comprehensive screening of shelter dogs in Oklahoma for exposure to vector-borne agents to enhance surveillance and to identify dogs in need of additional specific veterinary care.