Biological and Serological Studies on Toxoplasma Gondii in Lagos, Nigeria.

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Mensah, E.B
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University of Lagos
Sera from 775 persons in 10 age-groups, living in Lagos metropolis, were titrated for Toxoplasma antibodies, using the haemagglutination test. The overall percentage positive was 63.2%. The highest (78.4%) was found amongst the age group ranging from 36-40 years, whilst the lowest (48.2%) was recorded in the age group 11-15 years. The risk of nonimmune persons acquiring infection was calculated in the different age group using Van Der Veen's equation. Venous blood samples, cord blood, as well as placental tissue were also collected from a total of 452 pregnant women who attended some antenatal clinics in Lagos. Of the 452 samples studied 60.18% were positive for Toxoplasma antibodies. 70.7% the cord blood specimen collected were also positive. Transmission pattern of toxoplasmosis employing cats was studied, as faecal samples of cats collected randomly from different areas of Lagos were analysed, using the Formol-Ether Concentration technique after Ritchie (1948) to detect the presence of oocysts. The cats were also bled for serological tests. Those found to be negative were fed acutely-ill mouse, and the course of development of the parasite was observed.The effect of Toxoplasma infection on pregnancy was observed using mice models, and it was found that when pregnant mice were experimentally infected, intraperitoneally within the different thirds of their gestation period, death occurred, beginning from the 11th to the 29th day, and not earlier. Toxoplasma gondii trophozoites were maintained in vitro in different fluid media, with pH values ranging from 6.3 to 7.3. The length in days before the death of the infected mice was recorded and it was related to the viability and number of surviving organisms in the suspension. A graph in survival time against preservation time (both in days) was then drawn. The maximum length of survival at 40C was in whole human blood, as well as in foetal Bovine Serum, for up to 56 days. The molecular weight of the proteins present in the RH strain of Toxoplasma gondii laboratory prepared antigen (after Voller et at., 1976) was determined by gel filtration onSephadex G200 chromatography column. The absorbance of the 3 fractions derived were read at 280 nanometers, and the molecular weights were determined by extrapolation from a standard curve of ve/vo against the molecular weights of 4 standard proteins. The molecular weights ranged from 12,445 to 186,209 daltons.
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Serological , Toxoplasma , Biological Studies
Mensah,(1987). E.B, Biological and Serological Studies on Toxoplasma Gondii in Lagos, Nigeria,University of Lagos School of Postgraduate Studies PhD Thesis and Dissertation Abstracts, 165pp.