Davila, Edward Bradley (2023-08). Dogs, Cats, and Bats as Sentinels of Mosquito-Borne Arboviruses, Coronaviruses, and Typanosoma cruzi. Doctoral Dissertation.
Thesis
The focus of this dissertation was to determine if certain animals could to serve as sentinels of human disease. We sampled both domestic and wild animals and tested them for arthropod- borne pathogens and respiratory viruses to obtain seroprevalences and determine if there was any utility as a sentinel. A cross-sectional prevalence study was conducted in two Mexican states during 2019. Blood samples were taken from domestic dogs and tested for neutralizing antibodies for Zika virus, dengue virus 1, dengue virus 2, and West Nile virus. Positivity criteria required sampled to neutralize at least 90% of viral plaques in a monotypic reaction. We found that 42.6% of dogs from Reynosa, and 28.6% of dogs overall, exhibited antibodies against West Nile virus. We also found a single dog who was monotypically positive for dengue virus 2. The same dogs were tested for DNA and antibodies against Trypanosoma cruzi. Positivity criteria for antibody testing required two or more positive tests. We discovered two (0.7%) samples tested positive for parasite DNA, of which, one was discrete typing unit TcIV. Of 72 (24.3%) samples that were reactive on Stat-Pak, eight were reactive on Stat-Pak and MIA, and two were reactive on Stat-Pak and IFA. Overall, we recorded nine dogs that were positive for T. cruzi. Samples were collected from feral cats captured by the Bryan Animal Shelter in Brazos County, Texas between January and August 2021. Each cat had multiple swabs taken totaling 224 swabs and a blood sample. Swabs were tested for coronavirus RNA and blood was tested for antibodies against SARS-CoV-2. Swabs from four cats (7.1%) tested positive for feline coronavirus RNA. Zero cats tested positive for antibodies against SARS-CoV-2 via plaque reduction neutralization test. In February 2021, 285 Mexican free-tailed bats were opportunistically collected following Winter Storm Uri in Brazos County, Texas. An oropharyngeal swab was taken from each bat and tested for coronavirus RNA. Zero bats tested positive for coronavirus RNA. Animals and humans share a greater portion of their environments than ever before. Identifying capable animal sentinels can be a cost effective way to monitor a population's health and can serve as an important tool in disease surveillance and outbreak prevention.
