ars technica: Hawaii’s health department has released fresh warnings about a parasitic worm that can infest human brains after officials confirmed that three more visitors to the state picked up the infection.
The Centers for Disease Control and Prevention confirmed three new cases in unrelated adults visiting Hawaii Island from the US mainland, the health department announced. The latest known victims—who became infected at different times—bring the state’s 2018 case total to 10 and the 2019 total to five.
While there were 17 confirmed cases in 2017, the state counted only two cases total in the prior decade. The new case counts indicate a sustained boom in the parasite’s population and spread.
The parasitic worm in these cases is the rat lungworm, aka Angiostrongylus cantonensis. As its common name suggests, the wandering worm primarily takes up residence in rats’ lungs, where female worms lay their eggs. Young worms leave the nest early to find their own windy homes, though. Larvae get coughed up into rats’ throats then swallowed. The hosting rat eventually poops out the young parasites, which then get gobbled up by feces-feasting snails and slugs (intermediate hosts). When other rodents come along and eat those infected mollusks, the prepubescent parasites migrate to the rats’ brains to mature before settling into the lungs and reproducing. The cycle then starts again.
Humans are an accidental host, typically infected when they inadvertently eat an infected slug or snail that has slid into their salad fixings or other produce. Officials have blamed the recent boom in human cases, in part, on an explosion of an invasive “semi-slug,” which is particularly good at picking up the parasite. more here