Viability of Baylisascaris procyonis Eggs

Abstract

Infection with Baylisascaris procyonis roundworms is rare but often fatal and typically affects children. We attempted to determine parameters of viability and methods of inactivating the eggs of these roundworms. Loss of viability resulted when eggs were heated to 62°C or desiccated for 7 months but not when frozen at –15°C for 6 months.

Update on Baylisascariasis, a Highly Pathogenic Zoonotic Infection

“…The thick-walled eggs of B. procyonis may remain viable in the environment for several years (25), even when frozen at Ϫ15°C for 6 months. However, the eggs do not remain viable when they are heated to 62°C or when they are desiccated for 7 months (26). A seasonal peak in egg production has also been observed in fall months (September to November), with an apparent self-cure occurring in the winter and early spring in northern temperate regions (1,27).…”

“…The application of some form of heat, especially by the use of a steam-producing device or a propane flame gun, has been found to be the most effective decontamination method (1,2,6,25). The thermal death point of embryonated B. procyonis eggs is actually relatively low, and they are rendered inviable by exposure to a tem-perature of 62°C for less than 1 min (26,141). This temperature also inactivates the eggs of other ascarids, including A. suum and A. lumbricoides (142).…”

“…procyonis eggs have been found to be resistant to 90 min of treatment in undiluted household bleach and to survive at least 6 months at Ϫ15°C (26). Thus, for swimming pools that may be contaminated by raccoons, complete filtering or draining is indicated, since chlorination may not guarantee the killing of embryonated eggs (26). The application of some form of heat, especially by the use of a steam-producing device or a propane flame gun, has been found to be the most effective decontamination method (1,2,6,25).…”

Zoonosis Caused by Baylisascaris procyonis

“…However, the longevity of B. procyonis eggs and their resistance to disinfection or decontamination makes successful environmental cleanup difficult. Recently a publication (Shafir et al, 2011) showed that eggs survived complete desiccation for at least 6 months at room temperature. Total loss of viability was observed after 7 months of desiccation.…”

Illegal Wildlife Imports More than Just Animals—Baylisascaris procyonis in Raccoons (Procyon lotor) in Norway

“…Environmental contamination with B. procyonis eggs remains the greatest concern. These eggs are extremely environmentally resistant and have been known to remain infective for more than a decade when stored at 4 C as well as after storage in formalin (Sorvillo et al, 2002;Shafir et al, 2011). Domestic dogs can also act as the definitive host (Lee et al, 2010), and the farmer also bred a variety of dogs that had access to the animal pens.…”