Earthworms as paratenic hosts of toxoplasmosis in eastern barred bandicoots in Tasmania.

An experimental feeding study was designed to assess the role of earthworms in the transmission of Toxoplasma gondii infection to eastern barred bandicoots (Perameles gunnii). Six animals with no agglutinating antibodies to T. gondii were fed artificially cultured earthworms that had been maintained in autoclaved nutrient-enriched soil. Two animals were given earthworms that had been maintained in soil contaminated with T. gondii oocysts (P89/VEG strain); two animals were fed on earthworms, which initially had been exposed to soil containing T. gondii oocysts then transferred through three changes of sterile soil; two control bandicoots were fed earthworms maintained in sterile soil. Both bandicoots fed earthworms maintained in T. gondii contaminated soil died 11 and 14 days after feeding. The necropsy findings were consistent with acute toxoplasmosis. Bandicoots fed earthworms exposed to oocysts but then transferred through changes of sterilized soil remained healthy as did control animals. All surviving animals remained seronegative over the 6 wk observation period after feeding. These findings confirm that earthworms, a major component of the natural diet of P. gunnii, can transmit T. gondii infection. It appears that oocysts present in the alimentary tracts of the worms, rather than infective stages of T. gondii in worm somatic tissues, are responsible for these infections.

Epidemiology of giardiasis in Tasmania: a potential risk to residents and visitors.

BACKGROUND: Giardia infection is an ongoing problem in Tasmania and occurs throughout the state. It has been postulated that part of the problem is the reservoir of infection in native animals which is suggested to contribute to infections in humans. To date, however, no detailed study on the epidemiology of giardiasis in Tasmania has been carried out. METHODS: Information regarding the prevalence of Giardia infection in humans and the risk of intrafamilial transmission was obtained from the Department of Community and Health Services and from the direct examination of human or animal fecal samples. RESULTS: Giardia has been found to be present in a wide range of native and domestic animals and in humans of all ages from all over the state. CONCLUSIONS: Giardiasis is endemic in Tasmania and poses a risk to locals as well as to visitors to the state, especially those who participate in wilderness activities such as bushwalking. These people must be aware of the possible risk of Giardia infection and should take precautionary measures to avoid infection.