An investigation in congenital transmission of Toxoplasma gondii as a potential mode of transmission in mice and humans

Thomasson, D

Abstract

Toxoplasma gondii is a pathogenic Apicomplexan parasite with a worldwide
distribution in almost all warm blooded animals. The parasite is transmitted to hosts in
three ways; via oocysts that are passed from the definitive host the cat; by the
ingestion of tissue cysts by carnivory and by congenital transmission. The first two
routes being thought to be the most important modes of transmission. Mice are
thought to be primarily infected by the ingestion of oocysts in the environment while
the consumption of infected meat is thought to be the major source of human infection.
Recent data suggests, however, that vertical transmission may be important in both of
these species. This investigation uses PCR to address this issue.
Apodemus sylvaticus collected over a period of seven years from a rural area of
Yorkshire were tested by PCR and a prevalence of 46% was found in this population.
As there are few cats in this area, oocysts are not thought to be the source of infection.
A natural population of Mus domesticus captured by a pesticide company and housed
in a closed colony since 1991 were found to have alOO% prevalence of Toxoplasma
and all animals were infected with the same strain type, Type 1. These studies suggest
that congenital transmission may be occurring at high frequency.Congenital transmission in humans in the U.K. is thought to be rare. To determine if
congenital transmission occurs in normal healthy newborn babies we set up an
ethically robust protocol to collect umbilical cords from babies born in a hospital in
the U.K. Preliminary results show that T. gondii was detected in 65% of the cords and
all three different strain types were found. In conclusion congenital transmission may
occur much more frequently than previously thought in natural populations of animals
and humans.

Citation

Thomasson, D. An investigation in congenital transmission of Toxoplasma gondii as a potential mode of transmission in mice and humans. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2011