Digenetic trematodes, Acanthatrium sp. and Lecithodendrium sp., as vectors of Neorickettsia risticii, the agent of Potomac horse fever.

This research article focuses on the role of digenetic trematodes, Acanthatrium sp. and Lecithodendrium sp., as potential vectors of Neorickettsia risticii, the agent causing Potomac horse fever. The study shows that bats and swallows may act as hosts for these trematodes and can be a potential natural storage site for N. risticii.

Research Methodology

• The team pursued their investigation by collecting five bats (Myotis yumanensis) and three swallows (Hirundo rustica, Tachycineta bicolor) from a Potomac horse fever-endemic location in northern California.
• The collected specimens were then dissected, and major organs were examined for presence of the trematodes and for Neorickettsia risticii DNA.
• To detect the presence of N. risticii DNA, a ‘nested polymerase chain reaction’ (PCR) assay technique was employed. PCR is a common molecular biology method used to make multiple copies of a specific DNA segment, which allows the DNA to be visualized more easily.

Results and Findings

• On scrutiny, the adult digenetic trematodes, Acanthatrium sp., and/or Lecithodendrium sp., were found within the gastrointestinal tract of all the examined bats and one swallow.
• Three bats’ intestines, two bats’ spleens, one swallow’s liver, and spleen tested positive for N. risticii DNA.
• Out of seven pools of identical digenetic trematodes derived from single hosts, two pools of Acanthatrium sp. and one pool of Lecithodendrium sp. also tested positive for N. risticii via PCR.

Implications of the Study

• This research provides initial evidence that at least two trematodes from the Lecithodendriidae family could serve as vectors for N. risticii, the pathogen causing Potomac horse fever.
• The findings also suggest that bats and swallows might not only act as definitive hosts for these trematodes but also as potential natural reservoirs for the N. risticii bacterium.