JamesW. Curran

INACTIVATION OF HTLV-III/LAV-INFECTED CULTURES OF NORMAL HUMAN LYMPHOCYTES BY NONOXYNOL-9 IN VITRO

This letter describes the in vitro inactivation of human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) by nonoxynol-9 a nonionic surfactant. Peripheral blood lymphocytes from HTLV-III-negative healthy volunteers not in any risk group for acquired immunodeficiency syndrome (AIDS) were separated by density-gradient centrifugation and incubated with HTLV-III in a culture medium of RPMI 1640. Reverse transcriptase activity assays were done on days 2 4 8 10 and 12 on cells treated with nonoxynol-9 immediately after inoculation. Nonoxynol-9 treated and untreated HTLV-III infected cell cultures were used as negative and positive controls. Treatment of HTLV-III with nonoxynol-9 at final concentrations of 0.05% or greater resulted in undetectable virus by the ID-50 assay. Toxicity controls suggested that 2.5% nonoxynol-9 and lower concentrations were appropriate for ID50 determinations. To assess the effect of the cytotoxicity of nonoxynol-9 on the reverse transcriptase assay pure nonoxynol-9 was diluted to 50% 25% 10% 5% and 1% and added to actively growing uninfected normal human lymphocytes. The reverse transcriptase activity of HTLV-III infected nonoxynol-9 treated cultures was significantly less than that of untreated infected cultures. Thus nonoxynol-9 at concentrations of 0.05% or more seems to inactivate HTLV-III in vitro while 1% or more reduces live counts of the target lymphocytes. Commercially available spermicides contain 1-5% nonoxynol-9 and the protective effect of such spermicides against sexual transmission of HTLV-III via sperm should be considered.

EVALUATION OF A CLINICAL CASE-DEFINITION OF ACQUIRED IMMUNODEFICIENCY SYNDROME IN AFRICA

A provisional clinical case-definition for acquired immunodeficiency syndrome (AIDS) developed by the World Health Organisation (WHO) for use in Africa was tested on 174 inpatients at Mama Yemo Hospital, Kinshasa, Zaire. In this hospital population with a 34% infection rate of human immunodeficiency virus (HIV), the clinical case-definition had a specificity of 90%, a sensitivity of 59%, and a predictive value of 74% for HIV seropositivity. These results support the use of the WHO clinical definition for AIDS in Africa. However, since HIV prevalence and disease expression vary, similar evaluations should be carried out in different regions.

RISK FACTORS FOR HUMAN IMMUNODEFICIENCY VIRUS SEROPOSITIVITY AMONG CHILDREN 1-24 MONTHS OLD IN KINSHASA, ZAIRE

A prevalence study of antibody to human immunodeficiency virus (HIV) was conducted in Kinshasa, Zaïre, among 258 children 2-24 months old who were in hospital, 191 children 1-20 months old who were attending a well-child clinic, and their mothers. 8% of the mothers of both groups of children were seropositive. Among children under 9 months old, 12 of 102 (12%) hospital inpatients and 11 of 136 (8%) clinic attenders were seropositive, while in the 9-24-month age group 20 of 156 (13%) hospital children and only 1 of 55 (2%) clinic children were seropositive (Fishers exact test, p = 0.01). 61% of the seropositive children had seropositive mothers, indicating a high rate of vertical transmission. Factors associated with seropositivity among hospital children with seronegative mothers included male sex, increased lifetime number of medical injections, and previous blood transfusion or hospital admission. Among children who had not previously been transfused or admitted to hospital the seropositives had received more medical injections than the seronegatives (median 34.5 versus 14.5; Wilcoxon rank sum test, p = 0.006). HIV infection accounted for or complicated a substantial proportion of hospital paediatric admissions. Public health measures are urgently required to prevent parenteral and vertical transmission of HIV to infants and young children in Kinshasa.

Natural history of human immunodeficiency virus infection in Zaire.

The natural history of human immunodeficiency virus (HIV) infection in Zaïre was determined by identifying in October, 1984, 125 seropositive hospital personnel without signs or symptoms and 145 age and sex matched seronegative controls from the same population. Between July, 1985, and February, 1986, 67 seropositives, including 38 men and 29 women, and 113 seronegatives were interviewed and examined by an observer who did not know their serological status. The acquired immunodeficiency syndrome (AIDS) had developed in 1 seropositive and no seronegatives (rate difference, 1.3/100 person-years [py]; 95% confidence interval 0-3.3/100 py); AIDS-related complex or generalised lymphadenopathy had developed in 8 seropositives (12%) and 1 seronegative (1%) (rate ratio, 13.2; 95% confidence interval 1.3-134.6); and minimal lymphadenopathy had developed in 19 seropositives (28%) and 8 seronegatives (7%) (rate ratio, 3.9; 95% confidence interval 1.8-8.4). These data provide the first estimates for rates of progression to AIDS or AIDS-related conditions among healthy HIV seropositive heterosexual adults. Rates observed in this study are similar to those reported in US or European homosexual or bisexual men.

EXCESS DEATHS IN AFRICA FROM HIV : CONFIRMED AND QUANTIFIED

n While most reasonable observers acknowledge that HIV causes AIDS and death in Africa, others have argued that HIV is responsible for neither death nor AIDS on the continent. Recent findings from a two-year prospective cohort study by Mulder and colleagues, however, should put to rest claims by these latter skeptics. Mulders epidemiological study was conducted in rural Uganda to quantify excess mortality associated with HIV infection. It was found that young adults testing positive for antibody to HIV were sixty times as likely to die during the subsequent two-year observation period as were otherwise similar persons who tested negative. Mortality was well in excess of background rates in all age groups, but was highest in men and women aged 25-34 years who were most commonly infected with HIV. These findings should dispel any notion other than the reality that HIV infection is clearly an important cause of premature mortality throughout the world. One may realize the association between HIV infection and death even without believing that HIV causes AIDS.n

ELISA READERS AND HIV ANTIBODY TESTING IN DEVELOPING COUNTRIES

Enzyme-linked immunosorbent assay (ELISA) tests for antibodies to human immunodeficiency virus (HIV) yield a color reaction the absorbance value of which can be found with a spectrophotometer (reader). Such ELISA readers cost between

Infection of chimpanzees with lymphadenopathy-associated virus.

5000 and

PASSIVE ANAL INTERCOURSE AS A RISK FACTOR FOR AIDS IN HOMOSEXUAL MEN

15500. In developing countries buying and maintaining of a reader could be a barrier to widespread testing for HIV antibodies. Is an ELISA reader necessary? The Zairian National Research Program on AIDS (Project SIDA) was established in Kinshasa in mid-1984. The projects laboratory supports epidemiological immunological and clinical studies and also receives sera from patients with suspected AIDS or AIDS-related conditions and their families or sexual contacts. For anti-HIV testing the Bio-EnzaBead diagnostic kit (Litton Bionetics) and a Titertek Multiskan MC reader (Flow Laboratories) are used. ELISA positive sera are retested and repeatedly positive sera are confirmed by immunoblot. Previous studies in Kinshasa showed that almost all of several hundred repeatedly ELISA positive sera were confirmed by western blot. From February 4 to March 5 1986 the plates for all sera tested in the Project SIDA laboratory were upon completion of the ELISA protocol inspected by eye by 1 of 4 observers and recorded as positive (any color observed) or negative (no color). Any borderline plates were taken as positive. Immediately afterward the plates were analyzed with the reader. The cutoff was determined as per manufacturers instructions and sera were classified as positive (equal to or greater than the cutoff) or negative. 14 ELISA plates were tested on 12 days for a total of 1199 ELISAs. With spectrophotometry as the gold standard the sensitivity of visual reading was 99.2% and the specificity was 95.5% (table). Concordance betwee naked-eye and reader verdicts was 97.7%. Whether visual inspection can be an adequate substitute for spectrophotometry is a complex question. In developing countries replacing false-positive blood units may be cheaper than purchasing a reader and maintaining it (replacement parts servicing calibration and supplies). However other direct and indirect costs of an HIV antibody screening program including donor education confirmatory testing and counseling and follow-up of seropositive individuals must also be considered. The search for alternatives to spectrophotometers for ELISA reading underscores a general problem facing developing countries who want to test for HIV antibodies. Current ELISA technology is not especially suited to conditions in the developing world. Heat-stable tests that are reliable under field conditions simple to use highly sensitive (without excessive sacrifice of specificity) and inexpensive are needed to assist the developing world in the prevention and control of HIV infection. (full text)