Invasive Burmese pythons alter host use and virus infection in the vector of a zoonotic virus

Abstract

The composition of wildlife communities can have strong effects on transmission of zoonotic vector-borne pathogens, with more diverse communities often supporting lower infection prevalence in vectors (dilution effect). The introduced Burmese python, Python bivittatus, is eliminating large and medium-sized mammals throughout southern Florida, USA, impacting local communities and the ecology of zoonotic pathogens. We investigated invasive predator-mediated impacts on ecology of Everglades virus (EVEV), a zoonotic pathogen endemic to Florida that circulates in mosquito-rodent cycle. Using binomial generalized linear mixed effects models of field data at areas of high and low python densities, we show that increasing diversity of dilution host (non-rodent mammals) is associated with decreasing blood meals on amplifying hosts (cotton rats), and that increasing cotton rat host use is associated with increasing EVEV infection in vector mosquitoes. The Burmese python has caused a dramatic decrease in mammal diversity in southern Florida, which has shifted vector host use towards EVEV amplifying hosts (rodents), resulting in an indirect increase in EVEV infection prevalence in vector mosquitoes, putatively elevating human transmission risk. Our results indicate that an invasive predator can impact wildlife communities in ways that indirectly affect human health, highlighting the need for conserving biological diversity and natural communities.

Lizards Are Important Hosts for Zoonotic Flavivirus Vectors, Subgenus Culex, in the Southern USA

“…Shift in vector distribution is typically considered the major implication of climate change for vector-borne disease [e.g., (60)]. However, as exotic mosquito vectors can change the transmission dynamics and public health risks of mosquitovectored pathogens, so, too, can introductions of nonindigenous vertebrate hosts (61). Since Edman's work on Culex host associations in the 1960s, Florida's vertebrate community has transformed.…”

Everglades virus evolution: Genome sequence analysis of the envelope 1 protein reveals recent mutation and divergence in South Florida wetlands

“…Morphological methods were implemented to identify mosquitoes by species. Specimens of C. cedecei were pooled into 583 sample groups of 5–25 (mean = 24) adult females according to the collection site and date ( Burkett-Cadena et al 2021 ). This study involved the collection of mosquitoes from the Everglades.…”

“…In previous work, we investigated the indirect impacts of the invasion of the Burmese python in South Florida and showed a profound decrease in mammalian diversity, which was associated with a shift in viral kinetics in the vector mosquito ( Burkett-Cadena et al 2021 ). The loss of non-rodent animals in the Big Cypress Preserve resulted in increased feeding upon cotton rats by C. cedecei and a concomitant increase in the overall EVEV infection rate.…”

Size distribution and reproductive phenology of the invasive Burmese python (Python molurus bivittatus) in the Greater Everglades Ecosystem, Florida, USA

“…Recently, the common wolf snake (Lycodon capucinus) has been linked to the precipitous decline of lizard species on Christmas Island, AUS (Emery et al 2021). In continental USA, the invasive Burmese python (Python molurus bivittatus) has been linked to severe declines of mammalian prey populations and the accompanying ecological impacts in southern Florida's Greater Everglades Ecosystem (Dorcas et al 2012;Hoyer et al 2017;Burkett-Cadena et al 2021;Taillie et al 2021). The success of Burmese pythons is likely due, in part, to their size coupled with their reproductive biology (Willson et al 2011;Card et al 2018).…”

“…These large predatory snakes may have been introduced to, and established in, Everglades National Park by the mid-1980's or even earlier (Willson et al 2011). Since then, the species has spread across the entire southern portion of Florida and has been implicated in severe population declines of some midsized mammals in the area (Dorcas et al 2012;McCleery et al 2015), as well as in changes to vector-borne disease transmission dynamics (Hoyer et al 2017;Burkett-Cadena et al 2021), food-web perturbations (Reichert et al 2017), and spillover of parasites to native species (Miller et al 2018). However, little is known about much of the Burmese pythons' biology or reproductive phenology in the wild (but see Krysko et al 2012;Smith et al 2015).…”