Eaten alive on the Net

Abstract

According to the ProMED-mail list, The Morbidity and Mortality Weekly Report (4 Jan. 2002) of the US Centers for Disease Control and Prevention described two cases of severe encephalitis in children caused by Baylisascaris procyonis, one in Chicago and one in Los Angeles, one ending in severe brain damage and the other in death. Most racoon populations are infected with this intestinal parasite, and children are particularly at risk because they may transfer soil into their mouths that are contaminated with racoon faeces containing the eggs of B. procyonis. Many people like racoons and feed them or allow them to share dog or cat food with household pets. After 3–4 weeks outside, the eggs become infective and when ingested by young racoons, they develop into migrating larvae, which settle in the small intestine as adults, which can reach 14–18 cm long. Eating an intermediate host such as a mouse, squirrel or bird infected with the larvae often infects older racoons. In accidentally infected intermediate hosts (e.g. dogs or humans), larvae could migrate through the eye or the brain and cause extensive damage through a secondary inflammatory response. People are advised to treat decks, patios and other potentially contaminated surfaces with boiling water to reduce the risk of infection.Craig Stephen, a vet from the University of British Columbia, Canada, remarked that not only children are at risk: other animals in wildlife rehabilitation centres could acquire ‘nosocomial’ infections (those favoured by a hospital environment). He cited two cases, that of a dove and a squirrel, which had been housed in cages used for racoons previously; both developed fatal central nervous system disease.Another contributor pointed out that thorough cleaning was not enough and sent information from three websites (http://www.tc.umn.edu/∼devo0028/zoonos2.htm#15; http://www.wildcare.com/disinfect.htm; http://www.hrschicago.org/rabbitfr.html), which emphasize how long the eggs can survive and how tough they are. Decontamination procedures recommended include ‘autoclaving, flaming with gasoline, propane, or fuel oil, boiling in lye water…or boiling in Lysol’ and wearing a ‘ mask over the nose and mouth, disposable clothing, disposable gloves and heavy rubber boots that can be cleaned with boiling water’. Finally, Richard Montali (Smithsonian National Zoo, Washington DC, USA) said read the wonderful chapter on the ascarid by K.R. Kazacos in the 2nd edition of Parasitic Diseases of Wild Animals (2001, Chapter 11, pp. 301–341, Iowa State University Press).[This nematode was mentioned here once before, when a vet warned a student very firmly of the dangers involved in handling B. procyonis eggs in the lab; see Parasitol. Today (1998) 14, 478.]