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.

Detection of human immunodeficiency virus type 1 p24 antigen and plasma RNA: relevance to indeterminate serologic tests.

BACKGROUND: Most enzyme immunoassay-reactive specimens producing indeterminate Western blot results belong to individuals who are not infected with human immunodeficiency virus type 1 (HIV-1). However, a small percentage may correspond to early seroconversion or advanced disease, at which stage partial reactivity on Western blot may be observed. STUDY DESIGN AND METHODS: To determine the utility of HIV-1 p24 antigen and cell-free RNA detection for the resolution of Western blot-indeterminate serologic results, several types of enzyme immunoassay-positive, sero-indeterminate specimens were analyzed. Samples were obtained from infected individuals at the time of seroconversion (n = 20), from patients with AIDS (n = 2), as specimens from clinical samples obtained for diagnostic testing (n = 57), from blood donors producing persistent indeterminate results (n = 47), and from random blood donors (n = 72). RESULTS: HIV-1 p24 antigen was detected in 10 of 20 specimens collected from 9 of 12 individuals who seroconverted and in 2 of 2 AIDS patients. HIV-1 plasma RNA was positive in 22 of 22 samples from those 14 individuals. All of 57 diagnostic specimens and 47 samples obtained from persistently indeterminate donors were negative for HIV-1 p24 antigen and plasma HIV-1 RNA. One of 72 blood donor specimens was positive for HIV-1 plasma RNA and had borderline reactivity for p24 antigen. CONCLUSION: The detection of plasma RNA appears to be sensitive and specific; negative test results may be used to identify false-positive serologic reactions. The detection of p24 antigen and plasma RNA can also be used to confirm HIV-1 infection in persons with indeterminate serologic results associated with early seroconversion or late-stage disease.

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.

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.

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 2. Immunity aspects.

An extensive poliomyelitis outbreak due to type 1 poliovirus took place in Natal/KwaZulu, South Africa, in 1987-1988, causing 412 paralytic cases. This epidemic differed from a previously described outbreak in Gazankulu, South Africa, in 1982 in that it occurred against a background of relatively good immunity. Thus, only 12% of patients lacked antibodies to types 2 and 3, indicating lack of previous immunization, and 76% of healthy children sampled in the epidemic area had serological immunity to all 3 types of poliovirus. The occurrence of extensive outbreaks in relatively well-immunized communities emphasizes the need to maximize herd immunity and reduce reservoirs of infection in the gut and in the environment, which can be achieved only with oral polio vaccine.

Poliomyelitis outbreak in Natal/KwaZulu, South Africa, 1987-1988. 1. Epidemiology.

An epidemic of type 1 poliomyelitis occurred in Natal/KwaZulu in the eastern part of South Africa between December 1987 and November 1988. 412 poliomyelitis cases were reported, of whom 74% were younger than 5 years. The case-fatality rate was 8%. It is suggested that massive floods, experienced in the area 2 months earlier, triggered the outbreak.

HTLV-I-associated myelopathy: clinicopathologic correlation with localization of provirus to spinal cord.

A 49-year-old South African man developed a rapidly progressive myelopathy 14 months after blood transfusion and died 1 year after the onset of symptoms. Detailed pathologic examination of the spinal cord was consistent with the diagnosis of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although no HTLV-I viral particles, antigens, or nucleic acids were detected in situ, polymerase chain reaction assays revealed HTLV-I proviral DNA in cervical, thoracic, and lumbar levels of the spinal cord, with the greatest amount being detected at the thoracic level. These findings suggest that the pathogenesis of HAM/TSP depends on direct infection of neural or immune elements within the spinal cord.

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.

HIV-1 infection among heterosexual attenders at a sexually transmitted diseases clinic in Durban.

In a study of 2,682 selected attenders at a sexually transmitted diseases (STD) clinic for blacks in Durban, antibodies to human immunodeficiency virus type 1 (HIV-1) were detected in 63 (2.4%)--30 of 937 women (3.2%) and 33 of 1,745 men (1.9%). Women aged 15-19 years (P = 0.002) were at greater risk of HIV-1 infection than women of other age groups. Among men, HIV-1 seropositivity was associated with genital ulcer disease (GUD) (P = 0.007) and donovanosis (granuloma inguinale) (P = 0.02). Among seropositive men with donovanosis the probability of HIV-1 infection increased as the duration of lesions increased. When HIV-1 seropositive women were compared with a subgroup of 73 seronegative women with GUD, inflammatory cytological changes were associated with antibodies to HIV-1 (P = 0.02). Among women overall, HIV-1 seropositivity was associated with previous syphilis (P = 0.03). In men herpes zoster (P = 0.04) and in women lymphadenopathy (P = 0.002) accounted for HIV-1 seropositivity in patients with medical complaints. HIV-1 seropositivity in men with gonorrhoea and genital warts was less than in men without gonorrhoea (P = 0.001) and genital warts (P = 0.03). These results support the causal hypothesis of HIV transmission whereby mucosal discontinuity acts as a portal of entry for the virus. GUD and cervical inflammation secondary to STDs in seronegative subjects may facilitate HIV transmission. The relative risk of various STDs are probably dependent upon the duration of epithelial damage and exposure to HIV-1.

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)

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.

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.

Circulating and breast-milk anti-rotaviral antibodies and neonatal rotavirus infections: a maternal-neonatal study.

In view of the high prevalence of rotavirus (RV) diarrhoea in Indian (Asian) infants in South Africa, a hospital-based study of 124 mothers and their neonates was carried out to establish the prevalence of maternal and neonatal circulating anti-RV antibodies, RV antibodies in breast-milk, and neonatal RV infections in this population. Thirty-four per cent of the mothers and 38% of the neonates had complement-fixing (CF) serum antibodies. There was a significant correlation between maternal and cord blood antibody levels (p less than 0.001; chi-square test). Fifteen per cent of hospital-born newborns showed asymptomatic RV excretion while still in hospital, mostly at 2-6 days of age, but some even earlier, with two shedding the virus before the age of 24 h. This excretion occurred in both seronegative and seropositive babies. The breast-milk of only 3.2% of the mothers was positive for CF-anti-RV antibodies, implying that either these were not present in the breast-milk or that the CF-test employed was not sufficiently sensitive for detecting these antibodies in milk specimens. Eighteen (18.2%) of 99 infants followed up showed evidence of RV infection 1-7 months after birth; none was symptomatic; 12 excreted RV in the stools while 6 others seroconverted. Asymptomatic reinfection was documented in 4 of 14 babies who had been infected initially as neonates.

Asymptomatic rotavirus infections among normal Indian children in Chatsworth, Durban.

During a 27-month survey in Chatsworth, Durban, serum from 1,041 normal Indian children, ranging in age from birth up to 13 years, was tested for the presence of anti-rotavirus antibodies by means of a complement fixation test. It was found that from an initial high positivity rate of 47.7% in the newborn, there was a sharp drop to 23.8% in the 1-2-month age group (P = 0.0009). This low positivity rate was maintained up to the age of 9-11 months, after which it rose to 46.4% in the 12-17-month age group (P = 0.0006). There was a further significant rise between the 2-3-year and 4-5-year age groups, probably reflecting rotavirus infections in nursery school and/or in the home, the latter being nosocomially acquired from younger siblings. Stool samples were obtained from 829 of the above subjects: overall, 16.2% were positive for rotavirus antigen by enzyme-linked immunosorbent assay; the highest rate (29.5%) of asymptomatic rotavirus infection was in the 12-14-month age group. The data indicate that asymptomatic infection with rotavirus is not uncommon in this community and that older children continue to be exposed to and become infected with rotavirus.

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.