Environmental factors, species influence lungworm infection in snails


Giant African snails, HeÊ»eia, O’ahu; nearly 30% infected in the recent study. (Photo credit: Randi Rollins)

Different species of snails in Hawaii harbor varying amounts of infectious rat lungworm, the nematode (roundworm) known scientifically as Angiostrongylus cantonensis, which causes lungworm disease in rats. A recent study, conducted by a university of Hawaii to Mānoa’s graduate zoology student, found that environmental factors, such as precipitation, temperature, and the extent of green vegetation, influence rat lungworm infection in snails.

In an effort to advance research and treatments for lung worm disease in rats, researchers from EUH Mānoa formed the Mānoa Angiostrongylus research group, led by Robert cowie, teacher-researcher in EUH Mānoa School of Ocean and Earth Sciences and Technologies (SOEST). Randi Rollins, who conducted the study, works in Cowie’s lab.

“The snail’s ability to transmit rat lungworm depends on the environment and the host species, as human infection occurs primarily after ingestion of infected snails,” Rollins said.

little snail on hand
Ovachlamys fulgens on the researcher’s finger; 5% recently infected Oahu to study. (Photo credit: Randi Rollins)
Lungworms from adult male and female rats extracted from a rat (pen cap for size). (Photo credit: Randi Rollins)

In general, snails from rainy, cool, and green sites have higher infection levels than snails from dry, warm sites with less green vegetation. However, the prevalence of lungworm in rats does not increase at the same rate with the environment in all snail species. Some species, such as Veronicella cubensis, large brown slugs commonly seen after rain, have very low infection levels in hot, dry regions and moist, heavily vegetated areas. On the other hand, the rat lungworm is more prevalent in giant African snails in humid and cool areas than in hot and dry regions.

“This interaction between host species and their environment highlights the importance of considering the ecology of species harboring agents causing zoonotic diseases,” said Rollins. “I strive to identify gaps in our knowledge that can create a safer environment Hawaii and a more informed public.

Collaboration in EUH

The Mānoa Angiostrongylus research group includes scientists from the John A. Burns School of Medicine, the College of Tropical Agriculture and Human Resources and SOESTPacific Bioscience Research Center.

“The aim of our group is to foster collaboration between Mānoa units and to highlight the important research on rat lungworm disease being conducted here at EUH Manoa, ”Cowie said.

Each year in Hawaii, Lung worm disease in rats is responsible for debilitating disease, sometimes resulting in death.

Over the past two years, researchers, including experts in environmental ecology, parasitology, zoology, and human and animal diseases, have published eight studies, sharing new findings and developing tips for diagnosing and treating the disease. The team compiled a comprehensive catalog of information on several Angiostrongylus species, including other species that cause human and animal disease; summary of rat lungworm disease and its treatment for veterinary professionals; reported canine cases of lungworm disease in rats for the first time in Hawaii; provided updated guidelines on the diagnosis and treatment of lung worm disease in rats; and is currently involved in a new drug discovery project to treat it.

This effort is an example of EUH Mānoa’s research excellence goal: to advance the research and creative work enterprise (PDF), one of the four objectives identified in the 2015-25 Strategic Plan (PDF), updated in December 2020.

For more information see SOESTthe website of.

–By Marcie Grabowski


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