Ecological Risk Screening Summary - Bloodfluke Planorb (Biomphalaria glabrata)

Species that are considered uncertain risk need a more in-depth assessment beyond the Ecological Risk Screening Summary to better define the species’ risk to U.S. environments.

Biomphalaria glabrata, Bloodfluke Planorb, is a freshwater aquatic snail that is native to South America and the Caribbean. B. glabrata has received much research attention for its role as an intermediate host of the parasite Schistosoma mansoni, which causes the human disease schistosomiasis. This species has been introduced outside its native range through escape from schistosomiasis research laboratories or by hitchhiking on plants in the ornamental trade. B. glabrata became established in North Carolina, Egypt, Dominica, and Ukraine, although recent surveys have failed to find persistent populations in either Egypt or Dominica. In Egypt, it hybridized with the native snail B. alexandrina; both B. glabrata and the hybrid snails may have greater potential to transmit Schistosoma mansoni, although no information is available establishing a causal relationship between B. glabrata introduction and new or increased S. mansoni outbreaks. The History of Invasiveness for B. glabrata is classified as Data Deficient. The climate matching analysis for the contiguous United States indicates establishment concern for this species. The climate match was highest in the Southeast, around its current established location in North Carolina. The Certainty of Assessment for this ERSS is classified as Low because not enough information is available to demonstrate or refute negative impacts of introductions of this species. The Overall Risk Assessment Category for Biomphalaria glabrata in the contiguous United States is Uncertain.