The prevalence and transmission of hepatitis B virus infection in urban, rural and institutionalized black children of Natal/KwaZulu, South Africa.

The sera of statistically selected urban (805), rural (238) and institutionalized (127) black children were tested for markers of hepatitis B virus (HBV) infection. The age-standardized (6-14 years) prevalence rates of HBs antigenaemia for comparison between urban, rural and institutionalized children were 10%, 18.5% and 25.1% and the HBV exposure rates were 31.4%, 62.1% and 72.0% respectively. In the newborn to six years age group the prevalence rates of HBsAg and HBV exposure were 2.5% and 7.1% for urban children and 53.1% and 70.3% for institutionalized children. Peak prevalences of HBsAg occurred in the 6-8 year age group and were 14.4% and 22.6% in urban and rural children respectively. Hepatitis Be Antigen (HBeAg) was detected in 46.5% and antibodies to hepatitis Be antigen (HBeAb) in 10.0% of all HBsAg positive children. Multiple mechanisms involving horizontal rather than vertical transmission appeared to be important in urban children, with HBV exposure in females being significantly associated with ear-piercing (p less than 0.001) and scarification (p less than 0.05). In addition, HBsAg was detected in 25 of 29 pools of bloodfed mosquitoes caught at the children's institution and was negative in all four pools of unfed mosquitoes, suggesting that these arthropods may also be one factor in the horizontal spread of HBV infection. Familial clustering of HBV infection was suggested by a significantly higher (p less than 0.01) prevalence of HBsAg amongst family contacts of HBsAg positive urban children (17.7%) than in the control groups of family contacts of HBsAb positive children (8%) and children who were negative for all HBV markers (2.4%). The significance and implications of these findings are discussed.

Markers of hepatitis B in nurses and domestic staff in an area of high endemicity.

Results obtained in two sero-epidemiologic surveys of hospital personnel in Durban were collated to yield information on 423 nurses and 141 domestic staff. The prevalence of antibodies to HBV was 14.9 per cent in 101 white nurses, 52.5 per cent in 322 African nurses and 51.8 per cent in 141 African domestics. This represents a greater than eight times increase for white nurses and a 50 per cent increase for African nurses and domestics over that seen in the equivalent blood donor groups (P less than 0.001 in each case). Antibody prevalence increased with age for all three staff groups, as did the number of individuals exhibiting a marker pattern (HBcAb greater than HBsAb) suggestive of persisting infection. No white nurses but 14 (4.3 per cent) African nurses and 17 (12.1 per cent) African domestics were HBsAg positive, the antigenaemia in domestics representing a significant increase (P less than 0.001) over the 4.0 per cent seen in female African blood donors. Six of the nurses and two of the domestics were also HBeAg positive. African nurses in adult medical wards showed greatest exposure (57 per cent) closely followed by nurses working in outpatient departments (54 per cent) and as theatre staff (52 per cent). Lower exposure rates (40 per cent) were seen in paediatric and renal unit nurses. This contrasts with results obtained for doctors in the two surveys which indicated that while Indian and white doctors are at significantly higher risk in the African hospital, African doctors are not, and that doctors working in surgical and renal departments are at higher risk than doctors on adult medical wards.(ABSTRACT TRUNCATED AT 250 WORDS)

Persistence of hepatitis B antigen in Culex quinquefasciatus (Diptera: Culicidae).

Groups of wild-caught Culex quinquefaciatus Say, previously tested for the presence of hepatitis B surface antigen (HBsAg), were tested for the presence of hepatitis B e antigen (HBeAg). This antigen was detected at low levels in blood-fed, half-gravid, and gravid groups. A colony of Cx. quinquefasciatus was established in the laboratory and tested for the persistence of HBsAg and HBeAg. Five days after feeding on blood infected with HBsAg and HBeAg, 9 of 20 (45%) pools of Cx. quinquefasciatus were HBeAg-positive and 5 of 20 (25%) pools were HBeAg-positive; low levels of HBsAg and HBeAg were still detectable 28 d after the infective meal in 2 of 20 (10%) and 1 of 20 (5%) pools, respectively. A crude protease extract was prepared from colony mosquitoes, and the effect of this extract on HBsAg and HBeAg present in human serum was tested in vitro. After 20 h, tests for both antigens were still strongly positive. Low levels of HBsAg were detected in ovaries 7 d after infection. Salivary glands were HBsAg- and HBeAg-negative.

An evaluation of the capillus HIV-1/HIV-2 latex agglutination test using serum and whole blood.

The capillus HIV-1/HIV-2 latex agglutination (LA) test was evaluated for its potential as an initial screening test in primary health care. For the serum study, panels totalling 289 HIV-positive sera and 323 known HIV-negative sera plus 50 individual seroconversion samples were tested by capillus. Paired blood specimens were also collected in heparinized and plain tubes from 501 consecutive patients with newly diagnosed sexually transmitted diseases (STDs) attending an STD clinic at a Transvaal hospital. Overall, an initial sensitivity of 99.3% and an initial specificity of 99.7% were obtained by visual reading of the capillus HIV-1/ HIV-2 LA tests on serum samples. Capillus also detected 40 (80%) of the 50 seroconversion samples. Of the 501 paired plain and heparinized blood specimens, serum testing by enzyme immunoassay (EIA) and indirect immunofluorescence/ Western blot (IFA/WB) showed 147 (29%) to be HIV Ab positive. Capillus testing of the paired specimens correctly identified all 147 known positive patients and 345 of the 346 negative patients, thus showing an initial sensitivity of 100% and an initial specificity of 99.7% for the testing of heparinized whole blood by a relatively unskilled health worker. It was concluded that the capillus HIV-1/HIV-2 LA test would be suitable for use as a primary screening test in small outlying laboratories or primary health care clinics.

Viral infections in clinical pertussis.

Of 44 children with clinical pertussis 29 (66%) had serological evidence of concurrent infection with respiratory viruses or Mycoplasma pneumoniae. The commonest superinfection was by mycoplasma (32%), followed by respiratory syncytial virus (27%) and adenoviruses (16%). The high prevalence of viral infections, many being multiple, supports the theory that pertussis predisposes to such infections or vice versa.

Low prevalence of delta hepatitis virus infection among blacks in Natal.

The prevalence of delta hepatitis virus (DHV) infection among hepatitis B surface antigen (HBsAg)-positive black subjects in Natal was determined. A total of 172 subjects was tested for the presence of antibodies to DHV; all were HBsAg-positive. They comprised three groups: 51 urban children identified in a community-based seroprevalence survey, 81 subjects identified during a family study, and 40 institutionalised children. None of the 172 subjects was positive for antibodies to DHV. Based on calculations using a binomial distribution of infection, there was a 95% probability that the prevalence of DHV infection was below 30/100,000 HBsAg-positive persons. While DHV infection was found to be rare among blacks in Natal, the risk of delta hepatitis becoming widespread is ever-present, since the high incidence of hepatitis B virus infection in black children provides ample opportunity for the concomitant spread of DHV.

Vertical transmission of hepatitis B virus in Culex quinquefasciatus.

An investigation of the vertical transmission of hepatitis B virus (HBV) in Culex quinquefasciatus Say revealed the presence of low levels of the virus in adult F1 progeny from the first ovarian cycle of mosquitoes infected by feeding on HBV positive human blood. HBV was not transmitted vertically during the second, third and fourth ovarian cycles nor to the F2 generation. The salivary glands, ovaries and faeces of the F1 generation did not contain detectable levels of HBV. Progeny of female Cx quinquefasciatus mated with F1 males were negative for HBV.

Some early observations on HIV infection in children at King Edward VIII Hospital, Durban.

Nine black children aged between 3 months and 30 months of age, with human immunodeficiency virus type I (HIV-I) infection are described to draw the attention of health professionals in southern Africa to special clinical characteristics useful for recognising this problem, which has many shared features with common diseases of infancy and childhood in the Third World. The main presenting complaints were chronic cough and persistent diarrhoea and vomiting. These children frequently had diarrhoea (8 of 9 patients), mucocutaneous candidiasis (8), pneumonia (7), hepatosplenomegaly (9), significant lymphadenopathy (5) and wasting (5). All were infected by common bacteria, such as Gram-negative organisms, Mycobacterium tuberculosis and Campylobacter jejuni, or by opportunistic infections such as Candida or cytomegalovirus (CMV), or by both bacterial and opportunistic organisms. A raised total serum globulin level, anaemia, lymphopenia and a cerebrospinal fluid (CSF) pleocytosis were frequent findings. Incomplete data on parental HIV status suggest perinatal transmission. Three of the children were HIV-antigen positive. The diagnosis of full-blown acquired immunodeficiency syndrome (AIDS), using the stringent Centers for Disease Control criteria, is difficult in our situation because of limited diagnostic resources; however, using these criteria, and the clinical case definition for AIDS recommended by World Health Organisation, it is thought that probably 4 of these children could be considered as having AIDS.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and transmission of HTLV-I infection in Natal/KwaZulu.

A community-based seroprevalence survey for human T-cell lymphotropic virus type I (HTLV-I) was undertaken in the Ngwelezane district of Natal/KwaZulu. A total of 1,018 individuals was interviewed for risk factors and had blood drawn for serological examination. To exclude antibody cross-reactivity between anti-HTLV-I and anti-HTLV-II all Western blot HTLV-I-positive samples were further subjected to a Select HTLV test. For comparison, anonymous HIV testing was done. The areas of residence of patients with myelopathy associated with HTLV-I were also ascertained. The seroprevalence of HTLV-I was 2.6% (95% confidence interval (CI) 1.62-3.58). An age-related rise in HTLV-I seropositivity from 1.3% in the 15-24-year age group to 6.1% in the over 55-year-old group was noted. There was no significant association between HTLV-I antibody positivity and marital status, occupation, history of blood transfusion, scarification, age at first sexual experience and number of sexual partners. Anti-HIV-1 antibody testing revealed a positivity of 3.5% (95% CI 2.4-4.68) and the relative risk for co-infection with both HTLV-I and HIV-1 in the 15-24-year group was 1.16 (95% CI 1.08-1.24). The study also identified the first HTLV-II-seropositive case in the Natal/KwaZulu region. Up to December 1991, 90 cases of HTLV-I-associated myelopathy/tropical spastic paraparesis were seen at the Neurology Unit, Wentworth Hospital. The patients came from all parts of Natal, from Pongola in the north to Transkei in the south. The Natal/KwaZulu region is, therefore, an endemic HTLV-I area.

Microbiological studies during the perinatal period. An attempt to correlate selected bacterial and viral infections with intra-uterine deaths and preterm labour.

An investigation of the genital, amniotic fluid, placental and neonatal microflora in a population with a high prevalence of amniotic fluid infections and perinatal deaths is reported. Women presenting with preterm labour and intra-uterine death were investigated for the presence in vaginal secretions of a selected variety of pathogenic organisms, and the findings in these patients were compared with those in three groups of controls who presented with normal labour at term or late delivery or who required elective caesarean section as a result of cephalopelvic disproportion. Indirect evidence of infection was also sought by assaying cord blood for immunoglobulin levels and by testing for specific antibodies to well-known congenitally acquired pathogens. The results showed a significant relationship between gonococcal infection, serological evidence of Chlamydia trachomatis infection and preterm labour.

Peripheral nerve lesions in HTLV-I associated myelopathy (HAM/TSP).

Peripheral nerve dysfunction (PND) was found in as many as 43% of our patients with human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM/TSP). To evaluate the PND further we biopsied the sural nerve in 6 patients. The histological features were varying degrees of demyelination, remyelination, axonal atrophy and degeneration, and perineurial fibrosis. "Globule" or "sausage" formation was prominent in two of the specimens. Inflammatory infiltrates were absent. No deposits of IgG, IgM, IgA, or complement were detected in the biopsies. No viral antigen or proviral DNA was detected. It is proposed that the PND and the histological findings noted are part of HTLV-I-associated disease and not an unrelated disorder. The pathogenesis of the PND remains unclear. There was no evidence of direct viral infection. The histological findings could represent primary changes induced by viral-triggered release of soluble factors, such as cytokines or secondary changes to more proximal disease, e.g., root involvement.

Myelopathy associated with human T cell lymphotropic virus type I (HTLV-I) in natal, South Africa. A clinical and investigative study in 24 patients.

Unexplained spastic myelopathy in black (Zulu) patients, similar to that seen in the tropics, has previously been described from Natal, South Africa. Following reports linking the human T cell lymphotropic virus type I (HTLV-I) to spastic myelopathy, we undertook a prospective and retrospective search for HTLV-I antibodies in 36 patients who were labelled as having unexplained myelopathy; 24 (66%) were positive and HTLV-I was isolated from 4 out of the 6 patients whose peripheral blood lymphocytes were cultured. Eighteen (75%) gave a short history (less than 6 months). There was a female preponderance (71%), spinothalamic dysfunction was common (55%) and as many as half were severely disabled (50% wheelchair bound). Routine laboratory studies showed no specific trends apart from hypergammaglobulinaemia and CSF pleocytosis (greater than 5 cells/microliter in 66% of patients). The total CSF protein was raised (greater than 0.4 g/l) in 45% of patients. The IgG index was greater than 0.7 in 15 of 19 patients. Conventional myelography did not show any specific abnormalities. Computer assisted myelography was undertaken in 22 patients; 3 showed arachnoiditis and 2 spinal cord atrophy. Periventricular lucencies were seen in 1 of 10 patients who had computed tomography of the head. Nerve conduction studies demonstrated abnormalities in 46% of the patients indicating that subclinical peripheral nerve dysfunction was common. Visual evoked responses were abnormal in only 1 patient but brainstem auditory evoked response studies showed some abnormality in 42% of the patients. The finding of HTLV-I antibodies in a significant number, and the isolation of HTLV-I from the blood in 6 of our black patients with noncompressive myelopathy, represents a substantial clinical advance. Future studies should define more clearly the role of the virus in this disorder.