Sero-epidemiology of Toxoplasma gondii infection in young children in Nairobi, Kenya.

The exposure of 127 pre-school and young schoolchildren to Toxoplasma gondii was investigated by a serological survey of its antibody by means of the passive haemagglutination technique. The significant rise of prevalence of the antibody from 35% in pre-school to 60% in the early school age group suggests that poor sanitary habits and conditions and water shortage in primary schools may cause parasitic infection through contact between children which has not been previously suspected but should be investigated. The strange difference of prevalence of the antibody in the two sexes in the pre-school age children cannot be explained by any social aspects of life. It is therefore suggested the initial exposure of the two sexes to the protozoan is the same but that it acts selectively as a killer disease in the pre-school males either as a primary infection or, more probably, secondary to other lethal paediatric killer diseases. Further studies of the latter aspects in the tropics are needed.

HBV infection: prevalence of core antibody and other markers in urban based, black school children in Kenya.

This paper reports a study of 279 sera obtained from children attending five schools in Nairobi, the capital of Kenya which is situated in a non-malarious zone. Their ages ranged from six to 16 years. The surface antigen of hepatitis B virus (HBV) was detected in 13 children (4.7%) including seven boys and six girls. The core and surface antibodies were measured by radioimmunoassay on 125 of the samples to study the pattern of infection in childhood and the interrelationships of different parameters of the infection. The core antibody by itself was observed in four children (3.2%). A total of 31 samples (24.8%) had both core and surface antibodies, 19 (15.2%) had only surface antibody. Thus, 48% of all school children tested had serological evidence of past exposure to the virus. The implications of these findings are discussed.

Evaluation of five immunodiagnostic techniques in echinococcosis patients.

Double diffusion (DD), indirect haemagglutination (IHA), immunoelectrophoresis (IEP), latex agglutination (LA), and complement fixation (CF) tests were evaluated for sensitivity and specificity in the diagnosis of 141 surgically-proven Turkana echinococcosis patients and 10 controls. The overall sensitivities for the tests were: IHA, 86.7%; LA, 53.3%; CF, 63.3%; DD, 55.0%; IEP, 55.0%. LA and CF tests produced a high number of false positive results; IHA gave a false positive result in 10% of cases; no false positives were obtained with IEP and DD. A combination of the latter three tests would therefore offer the best chance of detecting specific anti-Echinococcus antibodies, with an average sensitivity of 62.7%. The possible reasons for the relatively high incidence of false negative values are discussed.

Autoantibody profile in thyroid diseases in black Kenyans.

A controlled prospective study of autoantibody profile on black Kenyan patients with non-toxic goitre (116), thyrotoxicosis (131) and age, sex matched hospital controls is reported. The prevalence of thyroid microsomal and thyroglobulin antibodies is 3.5% in smooth non-toxic goitre and is 5.2% in the nodular non-toxic goitre compared to 1% of the control. The results reflect that autoimmune thyroiditis is less common in Kenyan hospital controls and smooth simple goitre which is even more pronounced in case of multinodular simple goitre as compared to the Caucasians. The prevalence of microsomal antibody of 54% and the occurrence of high titres in 19% of the toxic group is relatively similar in Caucasians and black Kenyans. However, thyroglobulin antibody and parietal cell antibody are far less frequent in the Kenyan toxic group as compared to Caucasians. In conclusion, the black Kenyan toxic cases are reluctant to produce thyroglobulin and parietal cell antibodies while microsomal antibody production is unaffected. The latter is thought to be more significant in the development and progression of autoimmune thyroiditis. The dissociated behaviour of the two thyroid specific antibodies and thyrogastric axis in black Kenyans strongly suggest that the immunogenetic control of these and the related diseases is different in them as compared to the Caucasians.

A prevalence study of HIV antibodies in rural Kenya.

In order to describe the prevalence of HIV antibodies and AIDS in West Kenya, serological tests, including ELISA, and in some cases immunoblotting, were performed on whole blood collected on filter paper from 603 Kenyans. Serum samples from 55 of these persons underwent the same examinations, and 45 were further examined by immunofluorescence and a commercial ELISA. The majority of the Kenyans examined were residents of a province in West Kenya, while the others were students from other parts of Kenya, predominantly rural areas. Male/female ratio was 62/38. Median age was 18 years (range 0-70). Five Danes with previously demonstrated HIV antibodies, and 10 Danish controls were examined for HIV antibodies in filter paper whole blood, and in serum by ELISA and immunoblotting. The tests carried out on the filter paper blood were found to be reliable. Only one of the examined Kenyans had antibodies to HIV by both ELISA and immunoblotting, representing a prevalence of 0.17% (95% confidence limits: 0.00-0.93%). This low prevalence is not in accord with results previously presented from rural districts in Kenya.