KEMRI Hep-cell II hepatitis B surface antigen screening kit

BACKGROUND

Kenya is a high hepatitis B virus (HBV) endemic zone. Prevention of HBV transmission by transfusing safe blood is necessary. Kits for screening hepatitis B surface antigen (HBsAg) are usually imported and are expensive. Hence it has been difficult to screen donated and patient blood samples all over Kenya.

OBJECTIVE

To produce a HBsAg screening kit locally in order to be able to screen donated and patient blood samples all over Kenya.

DESIGN

A laboratory based study.

SETTING

Centre for Virus Research (CVR), Kenya Medical Research Institute (KEMRI), Nairobi.

METHOD

Purified HBsAg from plasma of carriers obtained from National Public Health Laboratories Services (NPHLS) was used to minimise guinea pigs to produce antihepatitis B (anti HBs) antibody. The anti HBs was then used to sensitise sheep red blood cells (SRBC). The final product was freeze dried (lyophilised) and its sensitivity and specificity was compared with other commercial kits.

RESULTS

The sensitivity and specificity of KEMRI Hep-cell II was found to be 98% and 99%, respectively. The kit was found to be stable and potent for one year whether kept 4 degrees C, 37 degrees C or room temperature.

CONCLUSION

KEMRI Hep-cell II was successfully produced locally. The sensitivity and specificity were comparable to other commercial kits. The kit was stable and potent for one year between temperature of 4 degrees C and 37 degrees C. The kit required only simple apparatus to carry out the test hence it can be used anywhere in Kenya. It was also cheap and affordable.

Human plasma derived hepatitis B vaccine: Kenyan experience

OBJECTIVE

To determine the efficacy and safety of hepaccine B.

DESIGN

Vaccination on first-come-first-served basis.

SETTING

Kenya Medical Research Institute (KEMRI) staff and families at Nairobi, Kenya.

PARTICIPANTS

A total of 107 vaccinees aged 0-10 years and 10 years and above.

MAIN OUTCOME

Antibody to hepatitis B surface antigen (anti HBs) checked one month after the third dose of the vaccine.

RESULTS

Ninety seven per cent of the vaccinees developed antiHBs. Side effects were few in the form of soreness at site of injection and headache.

CONCLUSION

Hepaccine B produced good immune response in vaccinees with minimal side effects.

Detection of HBV-DNA and HCV-RNA viral sequences by polymerase chain reaction in selected Kenyan samples and the relationship to HBV seromarkers

We undertook a study on selected samples from patients who had presented with viral hepatitis and conditions of the liver (liver cirrhosis, chronic hepatitis and hepatocellular carcinoma). Diagnosis, screening and confirmation for viral hepatitis was done using a battery of techniques: ultrasound, conventional serological methods (Hepatitis B surface Antigen [HBsAg] - Reverse Passive Haemagglutination [RPHA], Hepatitis B core Antibody [HBcAb] - Passive Haemagglutination [PHA], Alpha-feto Protein - RPHA), Hepatitis B e Antigen/Antibody [HBeAg/Ab] - Radioimmunoassay [RIA], Hepatitis C antibody [HCV-Ab] - Enzyme Immunosorbent Assay [EIA]. Due to the high specificity and sensitivity of the Polymerase Chain Reaction technique [PCR] in detecting the viral genomes, it was used to establish the presence of the HBV-DNA and HCV-RNA to correlate the serological diagnosis of their respective seromarkers. A total of 39 serum samples were tested comprising 11 blood donors, 8 chronic liver disease patients and 20 hepatocellular carcinoma cases. 4/19 (21%) HCV-antibody (C-l) reactive samples were found to be positive for HCV-RNA by PCR. 14 of the 19 (73.7%) including the 4 HCV-RNA positive cases tested positive for HBcAb. 6 of 11 (55%) HBsAg positive cases also tested positive for HBV-DNA by PCR, In 8 of 20 (40%) hepatocellular carcinoma cases, no aetiological role could be assigned to hepatitis B or C as only HBcAb was demonstrated in those cases.

Efficacy of hepatitis B vaccine in a rural community in Muranga, Kenya

One hundred and seventy four high risk cases were vaccinated at Muranga district in Kenya. The plasma derived HB vaccine was used in 61 cases (group 1) and recombinant HB vaccine was used in 113 cases (group 2). Fifty five cases (90.2%) in group 1 and 112 (99.1%) cases in group 2 seroconverted. Anti-HBc seroconversion occurred in one case during the study period. Significant anti-HBs seroconversion were obtained both for plasma derived HB vaccine and recombinant HB vaccine. In infants, there was statistically significant difference between the geometrical mean of anti HBs titres in group 1 and that in group 2. The recombinant vaccine was more effective than the plasma derived vaccine.

Seroepidemiological study for HBV markers and anti-delta in Kenya

An HBV carrier rate of 3.0% in outpatients and 1.4% in school children, was found in a sero-epidemiological survey in Muranga District, Kenya. The prevalence of anti-Delta in HBV carriers was 42%. The prevalence of HBV carriers and HBV marker positive cases was high in family members of HBV carriers. The yearly attack ratio of HBV was low in primary school children, non-carrier family members and even carrier family members. Mother to baby vertical transmission was very high when mothers were HBeAg positive HBV carriers. Such vertical transmission may now be of major importance.

A community based longitudinal study of viral hepatitis B in a rural community

Community based longitudinal epidemiological study of hepatitis B virus (HBV) was done in Maragua between June 1986 and November 1987. Hepatitis B surface antigen (HBsAg) carrier rate in the community was 3%. The high risk groups of HBV infection in the community were members of HBV carrier families and babies born to highly infectious mothers. Horizontal transmission of HBV at school did not seem to be very important.