In the heart of the city: Trypanosoma cruzi infection prevalence in rodents across New Orleans

Abstract

Background Trypanosoma cruzi - the causative agent of Chagas disease - is known to circulate in commensal pests, but its occurrence in urban environments is not well understood. We addressed this deficit by determining the distribution and prevalence of T. cruzi infection in urban populations of commensal and wild rodents across New Orleans (Louisiana, USA). We assessed whether T. cruzi prevalence varies according to host species identity and species co-occurrences, and whether T. cruzi prevalence varies across mosaics of abandonment that shape urban rodent demography and assemblage structure in the city. Methods Leveraging city-wide population and assemblage surveys, we tested 1428 rodents comprising 5 species (cotton rats, house mice, Norway rats, rice rats and roof rats) captured at 98 trapping sites in 11 study areas across New Orleans including nine residential neighborhoods and a natural area in Orleans Parish and a neighborhood in St. Bernard Parish. We also assayed Norway rats at one site in Baton Rouge (Louisiana, USA). We used chi-square tests to determine whether infection prevalence differed among host species, among study areas, and among trapping sites according to the number of host species present. We used generalized linear mixed models to identify predictors of T. cruzi infection for all rodents and each host species, respectively. Results We detected T. cruzi in all host species in all study areas in New Orleans, but not in Baton Rouge. Though overall infection prevalence was 11%, it varied by study area and trapping site. There was no difference in prevalence by species, but roof rats exhibited the broadest geographical distribution of infection across the city. Infected rodents were trapped in densely populated neighborhoods like the French Quarter. Infection prevalence seasonally varied with abandonment, increasing with greater abandonment during the summer and declining with greater abandonment during the winter. Conclusions Our findings illustrate that T. cruzi can be widespread in urban landscapes, suggesting that transmission and disease risk is greater than is currently recognized. Our findings also suggest that there is disproportionate risk of transmission in historically underserved communities, which could reinforce long-standing socioecological disparities in New Orleans and elsewhere.

Vegetation cover and biodiversity reduce parasite infection in wild hosts across ecological levels and scales

“…oral route) (Jansen et al 2015). Few studies have investigated the effect of body mass on T. cruzi occurrence (Orozco et al 2016, Ghersi et al 2020), but amongspecies comparisons suggest that larger-bodied marsupials and rodents tend to have higher prevalence and interact with a higher diversity of T. cruzi genotypes (Jansen et al 2015(Jansen et al , 2018.…”

Prevalence of Trypanosomiasis of Wild Rats (Rattus sp.) in Banjarnegara District and Potential Impact for Public Health

“…Molecular investigation showed the prevalence of T. cruzi in all host species was 11%, which included all positive rats from New Orleans but not in Baton Rouge. 27 A new public health problem arises from atypical human trypanosomiasis. Although humans have an innate protection against most Trypanosoma species, nineteen (19) cases of atypical human trypanosomiasis caused by the animal trypanosomes T. b. brucei, T. vivax, T. congolense, T. evansi, and T. lewisi have been recorded.…”

Shelter cats host infections with multiple Trypanosoma cruzi discrete typing units in southern Louisiana

“…These data suggest that differences in transmission dynamics (and potential mechanisms) may be occurring and cats may also become infected by the oral route through grooming or biting/eating bugs. Oral infections may also occur when feeding on rodents, which present T. cruzi infection rates of 11–76% in the region [ 5 , 47 ]. Further studies would be needed to clarify T. cruzi transmission mechanisms for cats and dogs.…”