G N Odaibo

Hepatitis B virus (HBV) infection is a major public health problem for over two billion people infected globally. Occupationally exposed persons are at high risk of HBV infection and, apart from medical personnel, there is dearth of information concerning the prevalence and awareness of HBV among this population in Nigeria. This study was designed to determine the levels of HBV awareness and prevalence of HBV infection among hairdressers in Ibadan, Nigeria. Hairdressers and teachers (unmatched controls) in four local government areas in Ibadan were tested for HBV infection using ELISA technique. Dried blood spot (DBS) samples were collected from 171 participants. DBS elutes from the samples were tested for HBV surface antigen (HBsAg). The rate of HBV infection was higher (p = 0.005) among the hairdressers (13.0%) than teachers (4.8%). However, teachers were better informed about HBV (38%) compared to hairdressers (13%; p = 0.0001). Differences in HBV awareness and occupation type were found to be significant (P = 0.001). Hairdressers are at high risk of HBV infection and may constitute a major source of HBV spread among urban dwellers, especially in areas where awareness is low. Routine HBV screening and appropriate interventions for hairdressers are recommended to interrupt HBV transmission.

There have been previous reports of inapparent infection and intermittent secretion of rabies virus in the saliva of apparently healthy dogs in some African countries, including Nigeria. The study was therefore aimed at examining the carrier status of rabies in apparently healthy Nigerian dogs in the settlement areas studied. Ninety-two swabs samples from oral mucosae of domestic dogs (mongrels) without vaccination history were assayed for lyssaviruses by tissue culture isolation test in Vero cells. Rabies or rabies-related viruses were recovered from eighteen, representing 19.6% of the samples. The study showed that lyssaviruses were present in 4 out of the 6 settlements of the study areas. Among the areas where the viruses were present, the rate of isolation ranged from 11.1% to 66.7%. Female dogs had a little higher infection rate (12.0%) than their male counterparts (7.6%). Among age groups, the highest rate of infection (66.7%) was detected in dogs aged one to 3 years while the rate of 3.7% was found in dogs aged less than one year. The results of this study agree with the carrier state of rabies in domestic dogs, the common reservoir hosts of its etiologic agents in Nigeria and the rest of Africa andAsia; this is a serious threat to humans in these settlements. Although the load of infective virus in saliva is lower than that in brain, saliva collection for rabies diagnosis is simple, safer, faster and cheaper. Thus we suggest that saliva samples could be used as an alternative to brain specimens for rabies virus antigen testing in dogs, especially, when it is not practicable to obtain brain specimen.

The study involved 60 (non-immunized), 14 (immunized against HBV), healthy Nigerian adults and 28 Nigerian patients with hepatitis. Their sera were tested for HBsAg, HBeAg, anti-HBe, anti-HBc, anti-HBs and anti-HCV while only 15 subjects with chronic hepatitis had HBV DNA assay by PCR. The subjects aged 21 to 72 years and comprised 75 male and 27 female adults. The prevalence of HBV infection by HBsAg and/or anti-HBc sero-positivity was 55.9%. Only HBsAg and anti-HBs were detectable in 21% each among immunized while HBsAg, HBeAg, anti-HBe, anti-HBc, anti-HBs were present in 58%, 20%, 6%, 32%, and 42% respectively in the non-immunized subjects. HBV DNA was positive in 86.7% of the 15 subjects. About fifty five percent of all subjects were infectious of HBV with 13.7%, 3.9%. 32.3% and 4.9% accounting for high, medium, low and very low infectivity respectively while 44.1% and 1% of the subjects were susceptible and naturally immuned to HBV respectively. Coinfection with HCV tends to favour HBV infectivity. In conclusion, the infectivity of HBV among Nigeria is varied but high and a great proportion of the population is susceptible.

Primary HepatoCellular Carcinoma (PHCC) has been strongly associated with HBV and HCV infections among other aetiological factors. However; do the patients still spread the viruses? This study involved forty one Nigerian adult patients with PHCC and 45 controls who were tested for HBsAg, HBeAg, Anti-HBe, Anti-HBs, anti-HCV IgM and IgG, anti-HDV and HDV antigen using ELISA. Statistical analysis was carried out with the student - t - test and Mc Nemar test at p < 0.05. The subjects consisted of male:female ratio of 3:1 for both the PHCC patients and controls. Evidence of exposure to hepatitis B, C and D viruses was detected in 95.1%, 44% and 0% of the patients respectively while the respective values of 24%, 11.1% and 0% were obtained for the controls. Indication for high (HBeAg) and low (anti HBe) HBV viral replication, and acute HBV infection were detected in 12.5%, 92.7% and 2.2% respectively among the patients while only 35.6% of the controls had low HBV viral replication. Acute and chronic infections of HCV were also found in 26.8% and 24.4% of the patients respectively compared to the respective values of 2.2% and 11.1% of the controls. Occult HBV infection occurred in equal proportions (11%) of both the patients (31.7%) and controls (35.6%). In conclusion, infectious HBV and HCV particles are present among Nigerian patients with PHCC while HDV infection is uncommon. Hence, safe medical care should be practised for all patients with PHCC while relatives should be screened for these viruses.

We evaluated the prevalence and association of Genital Ulcer Diseases (GUDs) among HIV-1 infected female commercial sex workers (FCSWs) in Ibadan, Nigeria. A total of 250 FCSWs from brothels in Ibadan were tested for presence of antibodies to HIV and Syphilis. Pelvic examinations for signs of sexually transmitted infections (STIs) were carried out on the subjects. Endocervical and high vaginal swabs were collected from each of the subjects to establish laboratory diagnosis of STIs. Their age ranged from 15 to 55 years (Mean = 25.8 yrs; SD = 3.74). Majority (246/250) were Nigerians, while 1.6% were from neighboring West African countries. Sixty four (25.6%) of the subjects were positive for HIV-1 while seven (2.8%) had dual HIV-1/2 infection. Analysis of the STIs showed that 49 (19.6%) of the CSWs had GUDs. Herpes genitalis was the commonest GUDs as it occurred in 25 (10%) of the subjects. Other STIs identified were chancroid (5.6%), syphilis (4.0%) and lymphogranuloma venerum (LGV) (4%). Sixteen (64.0%) of the CSWs with herpes genitalis had HIV-1 infection. The risk ratio of herpes genitalis for HIV acquisition was 3.0 (95% CI: 2.0 - 4.4). Syphilis and chancroid were also found tobe significantly associated with increased risk of HIV infection (p < 0.0001). The adjusted odd ratios for Herpes genitalis, chancroid, and syphilis were 3.7 (1-13.0, p < 0.05), 19.8 (2.7-13.0, p < 0.05) and 19.1 (1-231.0, p < 0.05) respectively. There is need to educate FCSWs continually to adopt safer sexual behaviours, seek early diagnosis and treatment of GUDs to reduce their risk of transmitting HIV infection.

Various target groups have been identified in Nigeria for studying the prevalence of hepatitis B virus infection; however there is no information on its prevalence among workers in slaughter houses. This study determined the seroprevalence of hepatitis B virus infection in Nigerian butchers at Ibadan, and comprised 360 healthy Nigerian adult subjects (180 butchers, 180 traders as controls) selected by multistage stratified sampling. A questionnaire was used to collect relevant information and included points about risk behaviour. ELISA was used to detect the hepatitis B surface antigen in the serum; the seroprevalence rate in butchers and controls was 9.4% and 3.3%, respectively (p<0.05). Risk behaviour was seen more commonly in butchers than in controls. The presence of hepatitis B surface antigen in the serum was not related to the duration of occupational exposure or the number of partners. In summary, butchers comprise a high-risk occupational group for exposure to hepatitis B virus infection. We conclude that routine screening for parenterally acquired infections in this group is thus necessary in order to identify those who will require treatment and immunisation, especially against hepatitis B virus infection.

Respiratory problems like Pneumocystic carinni and Pulmonary tuberculosis (PTB) are among the common opportunistic infections in patients with HIV/AIDS. The risk of acquiring Mycobacterium tuberculosis in a community becomes greater with increase in the number of HIV positive persons with active tuberculosis. This study was carried out to determine the magnitude of HIV infection among PTB patients in different parts of Nigeria as part of the year 2000 national HIV surveillance programme. Blood samples were collected on blotting paper from a total of 2826 individuals attending TB clinics between 1st of September and 1st November, 2000. Samples were collected from patients with confirmed PTB from 12 states in the 6 geopolitical/health zone (2 states/zone) of Nigeria as part of high risk sentinel population groups. Samples were tested for the presence of HIV antibodies using commercial ELISA (Genescreen HIV-1/2, Sanofi Pasteur, Paris). All initially reactive samples were retested with a rapid EIA (Gene II, Sanofi Pasteur, Paris) according to the WHO recommendations (option II). HIV Prevalence in the states varied from 4.2% in Oyo to 35.1% in Benue States with a median prevalence of 17.0%. HIV Prevalence increased with age to a peak of 23.9% among PTB patients 30-39 years and then declined progressively to 12.8% among those 60 years and above. A relatively high HIV infection rate (13.8%) was found among the young adolescent age group 10-19 years. There was no significant difference in the rate among male and female PTB patients tested. Comparison with results of previous HIV sero-surveys shows a steady increase in HIV prevalence among PTB patients over the years. The high prevalence of HIV among young PTB patients aged 10-19 years in this study is worrisome and must be noted for intervention.

Several factors including variability of human immunodeficiency virus (HIV), laboratory facilities, cost and competence of personnel handling the tests are some of the important factors that affect accuracy and reliability of HIV testing in most parts of Africa. Recently investigators in Africa have observed that antibody detection assays based on antigens derived from HIV-1 subtype B show moderate to significantly lower sensitivity for detection of infection by various non-B subtypes. In this study, we evaluated the reliability of two EIA and 12 rapid HIV-1/2 test kits that are commercially available in Nigeria using the Western immunoblotting technique as reference. A panel of 100 sera from Western blot confirmed symptomatic or asymptomatic HIV-1 infected persons and 90 seronegative patients from those referred for testing in our laboratory were used for this study. Each sample was tested with two HIV-1/2 EIA, and 12 HIV-1/2 rapid test kits commercially available at one time or the other for HIV-1/2 testing in Nigeria. Overall, the sensitivity of the two EIA kits were 100% and 91.0% with specificity of 96.7% and 91.1% respectively. The sensitivity of the rapid test kits ranged from 88% to 98.0% with specificity of 92.2% to 100%. Further analysis showed significant variation in the sensitivity and specificity of the same kit based on whether an individual had asymptomatic or symptomatic infection The results of this study highlight the problem of diagnosis of HIV infections in Africa. It shows that the sensitivity of most of the rapid assays shall not be adequate for detection of early infection. The implications of possible misdiagnosis on the various intervention strategies that rely predominantly on correct HIV status of an individual are enormous. Thus, there is an urgent need for review of the current HIV testing assays or algorithms in Nigeria and other parts of Africa.

Isolates of hepatitis B viruses were collected from 20 acute and chronic hepatitis patients in a highly endemic region of Nigeria. Sequencing classified the isolates to the ayw4, as they all contained the amino acid variations characteristic for that serotype. In the pre-S2 region of five isolates, three to seven amino acids were deleted, suggesting that immune escape mutations previously associated only with chronic HBV infection may be observed also in acute disease. Phylogenetic analysis of the complete pre-S2/S (large S) genes (831 nt) demonstrated that all the viruses belonged to the same genotype E. So far, no isolates of genotype E have been found in any other region of the world, including the Americas. This may suggest a relatively recent introduction of this genotype into humans and would explain the relatively low genetic diversity of viruses belonging to this genotype. One genotype E virus had been found previously in a chimpanzee, and viruses belonging to the CHIMP genotype are related to other genotype E viruses. These findings are compatible with a transmission of genotype E viruses from chimpanzees to humans.