A Serological Survey of the Prevalence of Antibodies to Toxoplasma Gondii in Animals and in Man in Kenya

Abwajo, Josphat Twelo (1984) A Serological Survey of the Prevalence of Antibodies to Toxoplasma Gondii in Animals and in Man in Kenya. Masters thesis, University of Nairobi.

PDF (A SEROLOGICAL SURVEY CF THE PREVALENCE 07 ANTIBODIES TO TOXOPLASMA GONDII IN ANIMALS AND IN MAN IN KENYA) Abwajo_A Serological Survey Of The Prevalence Of Antibodies To Toxoplasma Gondii In Animals And In Man In Kenya.pdf - Accepted Version Restricted to Repository staff only until 31 December 2030. Download (4MB)

Abstract

Toxoplasmosis is a widespread zoonotic disease, caused by a rotozoan parasite, Toxoplasma Gondii. Toxoplasma infections have been recorded all over the world in most of the domesticated and wild animals, birds and man. Man can acquire the disease by ingestion of Sporocysts from infected cats or from the ingestion of inadequately cooked meat of infected food animals.Toxoplasmosis is a relatively uncommon clinical disease, although some of its manifestations are serious. Congenital toxoplasmosis is a medically and economically important disease, in both human beings and animals. In younger animals, toxoplasmosis may be fatal, causing considerable economic losses in sheep and goats. Only limited studies on Toxoplasma infection have been carried out in domestic animals and man in Africa. The prevalence of Toxoplasma infection in Kenya is not known with certainty, and only a few records have been found concerning the prevalence of the infection in animals and man in this country.The main objective of the work described in this thesis was to provide some data on the prevalence of toxoplasma gondii infection in some animal species and in man in Kenya. The Sabin and Feldman dye test (DT) has been considered the most reliable method for the detection of antibodies to Toxoplasma, and is still used as a reference test for comparison with other methods. In recent years, an enzyme immunoassay (ELISA) has been adapted as an adequate and more easily performed alternative method. The ELISA was used in this study for the detection of antibodies to Toxoplasma in random serum samples from goats, sheep and man. Antigen preparation consisted of peritoneal fluid from mice infected experimentally with live virulent tachyzoites of the RH strain of T. gondii. It was anticipated that the use of a crude non-purified antigen preparation which contained mouse serum components, especially mouse immunoglobulin, might give rise to falsepositive reactions in ELISA. Immuno-diffusion and imrnunoelectrophoresis, experiments revealed that anti-sera produced against the igG of %one species would react with immunoglobulins of other species, including mouse immunoglobulins. Since mouse immunoglobulins present in the Toxoplasma antigen preparation would adsorb to the plastic plates used in the ELISA, it was found that anti-sera to goat, sheep and human IgG had to be absorbed with mouse serum before species specific enzyme - conjugates lacking antibody activity mouse immunoglobulins could be prepared. In most cases the IgG fraction obtained by DEAE - cellulose chromatography of an absorbed antiserum was used for the preparation of enzyme conjugates, but purified antibodies were also occasionally used to obtain conjugates with high antibody activity and specificity. In addition, normal mouse serum was added to the conjugates to abolish all antibody activity to mouse immunoglobulins. Although the procedures outlined above resulted in a considerable decrease in false positive reactions – a conclusion based on the absence of reactions by these conjugates when tested on plates coated with dilution of normal mouse. Peritoneal fluid or mouse serum - two additional factors were considered crucial to achieving maximum specificity for Toxoplasma antibodies. Firstly, the mouse immunoglobulin adsorbed to the plates might possess antibody activity to the immunoglobulins of the species whose serum was being tested in ELISA. Secondly, the test serum might possess antibody activity to mouse immunoglobulins adsorbed to the plates. In both cases

Item Type:	Thesis (Masters)
Subjects:	R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine S Agriculture > SF Animal culture
Divisions:	Africana
Depositing User:	Geoffrey Obatsa
Date Deposited:	05 Jul 2016 08:55
Last Modified:	05 Jul 2016 08:55
URI:	http://thesisbank.jhia.ac.ke/id/eprint/627

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