Toxoplasmosis in England

The specificity of the Sabin-Feldman dye test with reference to protozoal infections

Infections of Eimeria stiedae in normal and splenectomized rabbits and of Leishmania enriettii in normal rabbits and guinea-pigs and in splenectomized rabbits did not produce dye test antibodies. Guinea-pigs injected with Atoxoplasma sp. and rabbits immunized with cultures of Crithidia fasciculata were found to be negative for dye test antibodies. Mice which had been infected with Trypanosoma cruzi did not show dye test antibodies. All these animals, except one guinea-pig infected with Leishmania enriettii, were negative in the complement-fixation test for toxoplasmosis using the egg antigen. These findings are discussed in the light of previous reports.

Topographical localization of distinct antigenic domains of Toxoplasma gondii with the aid of monoclonal antibodies

In the present study, a panel of six individual hybridoma derived antibodies produced against the BK strain of Toxoplasma gondii were evaluated for their reactivity in an immunofluorescence test. Each of the six monoclonal antibodies demonstrated a unique pattern of fluorescence localized to distinctive regions on the toxoplasmas. Although all of the six detected antigenic determinants which were shared by at least four different T. gondii strains, monoclonal antibody TG-E4A17 has disclosed hitherto unrecognized population differences among the BK or PH strain parasites. The fact that some of the antigenic molecules are restricted to distinct regions of the toxoplasmas may have implications in the infections process/immune response.

Toxoplasmosis and the wild rabbit Oryctolagus cuniculus in Victoria, Australia with suggested mechanisms for dissemination of oocysts

Sera or serum eluates from 1697 wild rabbits [Oryctolagus cuniculus (L)], collected over the past 10 years from 24 sites in 5 geographic regions of Victoria, were examined for antibodies to Toxoplasma gondii. Sera generally were classified into three broad groups, negative (titre less than 10), weakly reactive (titre 10 to 100) and strongly positive (titre greater than 1000). Strongly positive sera came from rabbits collected in a small number of localized areas, most significantly the Melbourne and Metropolitan Board of Works (MMBW) Sewerage Farm at Werribee and Mud Island in Port Phillip Bay.

Toxoplasmosis

Summary

Toxoplasma is unique among protozoa in its wide distribution and lack of host or tissue specificity. It is a successful parasite in so far as it rarely causes death of the host. The infection is frequently inapparent and this type of infection may be passed from mother to foetus with disastrous results. In domestic animals, it is a cause of serious economic losses, especially among lambs in this country and New Zealand. It may be associated with concomitant infections such as distemper in dogs and helminth infection in cats. In man lymphadenopathy is the commonest clinical manifestation; various affections of the eye and pneumonia also occur. The means of transmission in nature is still unknown apart from the congenital form. It is, however, regarded as a zoonosis and women should take special care where sick animals are concerned. They should be excluded from experimental work on toxoplasmosis. The reaction of the parasite to drugs is unlike that of most protozoa, but curative treatment is possible.