April 14, 2010
April 14 - Mesocestoides variabilis
Yesterday, we saw a brand new species of parasite. Today's parasite has been known to science for almost 100 years, but it still a bit of a mystery. Mesocestoides variabilis is a species of cestode, or tapeworm, that was first described in 1927. It has been reported from a wide variety of hosts - adults in foxes, cats, skunks and other carnivores and larval worms in smaller critters like lizards, birds, and small mammals, but it seems likely that what is commonly identified as Mesocestoides variabilis is actually a group of different species and genetic evidence seems to corroborate this. Although these tapeworms seem to primarily be found in wild hosts and occasionally domestic carnivores, there was one case a few years ago of an infection in a child. It appeared that the 19-month old boy had consumed Cajun sausage made of "wild animal viscera"!
This image is from the CDC Public Health Image Library.