Joan K. Kreiss

Vaginal Lactobacilli, Microbial Flora, and Risk of Human Immunodeficiency Virus Type 1 and Sexually Transmitted Disease Acquisition

A prospective cohort study was conducted to examine the relationship between vaginal colonization with lactobacilli, bacterial vaginosis (BV), and acquisition of human immunodeficiency virus type 1 (HIV-1) and sexually transmitted diseases in a population of sex workers in Mombasa, Kenya. In total, 657 HIV-1-seronegative women were enrolled and followed at monthly intervals. At baseline, only 26% of women were colonized with Lactobacillus species. During follow-up, absence of vaginal lactobacilli on culture was associated with an increased risk of acquiring HIV-1 infection (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.2-3.5) and gonorrhea (HR, 1.7; 95% CI, 1.1-2.6), after controlling for other identified risk factors in separate multivariate models. Presence of abnormal vaginal flora on Grams stain was associated with increased risk of both HIV-1 acquisition (HR, 1.9; 95% CI, 1.1-3.1) and Trichomonas infection (HR, 1.8; 95% CI, 1.3-2.4). Treatment of BV and promotion of vaginal colonization with lactobacilli should be evaluated as potential interventions to reduce a womans risk of acquiring HIV-1, gonorrhea, and trichomoniasis.

AIDS virus infection in Nairobi prostitutes: spread of the epidemic to East Africa

The acquired immunodeficiency syndrome (AIDS) is epidemic in Central Africa. To determine the prevalence of AIDS virus infection in East Africa, we studied 90 female prostitutes, 40 men treated at a clinic for sexually transmitted diseases, and 42 medical personnel in Nairobi, Kenya. Antibody to human T-cell lymphotropic virus Type III (HTLV-III) was detected in the serum of 66 percent of prostitutes of low socioeconomic status, 31 percent of prostitutes of higher socioeconomic status, 8 percent of the clinic patients, and 2 percent of the medical personnel. The presence of the antibody was associated with both immunologic and clinical abnormalities. The mean T-cell helper/suppressor ratio was 0.92 in seropositive prostitutes and 1.82 in seronegative prostitutes (P less than 0.0001). Generalized lymphadenopathy was present in 54 percent of seropositive prostitutes and 10 percent of seronegative prostitutes (P less than 0.0001). No constitutional symptoms, opportunistic infections, or cases of Kaposis sarcoma were present. Our results indicate that the epidemic of AIDS virus infection has, unfortunately, spread extensively among urban prostitutes in Nairobi, Kenya. Sexual exposure to men from Central Africa was significantly associated with HTLV-III antibody among prostitutes, suggesting transcontinental spread of the epidemic.

Hormonal contraception, vitamin A deficiency, and other risk factors for shedding of HIV-1 infected cells from the cervix and vagina

BACKGROUND Factors that influence shedding of HIV-1 infected cells in cervical and vaginal secretions may be important determinants of sexual and vertical transmission of the virus. We investigated whether hormonal contraceptive use, vitamin A deficiency, and other variables were risk factors for cervical and vaginal shedding of HIV-infected cells. METHODS Between December, 1994, and April, 1996, women who attended a municipal sexually transmitted diseases (STDs) clinic in Mombasa, Kenya, and had previously tested positive for HIV-1, were invited to take part in our cross-sectional study. Cervical and vaginal secretions from 318 women were evaluated for the presence of HIV-1 infected cells by PCR amplification of gag DNA sequences. FINDINGS HIV-1 infected cells were detected in 51% of endocervical and 14% of vaginal-swab specimens. Both cervical and vaginal shedding of HIV-1 infected cells were highly associated with CD4 lymphocyte depletion (p = 0.00001 and p = 0.003, respectively). After adjustment for CD4 count, cervical proviral shedding was significantly associated with use of depot medroxyprogesterone acetate (odds ratio 2.9, 95% CI 1.5-5.7), and with use of low-dose and high-dose oral contraceptive pills (3.8, 1.4-9.9 and 12.3, 1.5-101, respectively). Vitamin A deficiency was highly predictive of vaginal HIV-1 DNA shedding. After adjustment for CD4 count, severe vitamin A deficiency, moderate deficiency, and low normal vitamin A status were associated with 12.9, 8.0, and 4.9-fold increased odds of vaginal shedding, respectively. Gonococcal cervicitis (3.1, 1.1-9.8) and vaginal candidiasis (2.6, 1.2-5.4) were also correlated with significant increases in HIV-1 DNA detection, but Chlamydia trachomatis and Trichomonas vaginalis were not. INTERPRETATION Our study documents several novel correlates of HIV-1 shedding in cervical and vaginal secretions, most notably hormonal contraceptive use and vitamin A deficiency. These factors may be important determinants of sexual or vertical transmission of HIV-1 and are of public health importance because they are easily modified by simple interventions.

Correlates of Mother-to-Child Human Immunodeficiency Virus Type 1 (HIV-1) Transmission: Association with Maternal Plasma HIV-1 RNA Load, Genital HIV-1 DNA Shedding, and Breast Infections

To determine the effects of plasma, genital, and breast milk human immunodeficiency virus type 1 (HIV-1) and breast infections on perinatal HIV-1 transmission, a nested case-control study was conducted within a randomized clinical trial of breast-feeding and formula feeding among HIV-1-seropositive mothers in Nairobi, Kenya. In analyses comparing 92 infected infants with 187 infants who were uninfected at 2 years, maternal viral RNA levels >43,000 copies/mL (cohort median) were associated with a 4-fold increase in risk of transmission (95% confidence interval [CI], 2.2-7.2). Maternal cervical HIV-1 DNA (odds ratio [OR], 2.4; 95% CI, 1.3-4.4), vaginal HIV-1 DNA (OR, 2.3; 95% CI, 1.1-4.7), and cervical or vaginal ulcers (OR, 2.7; 95% CI, 1.2-5.8) were significantly associated with infant infection, independent of plasma virus load. Breast-feeding (OR, 1.7; 95% CI, 1.0-2.9) and mastitis (relative risk [RR], 3.9; 95% CI, 1.2-12.7) were associated with increased transmission overall, and mastitis (RR, 21.8; 95% CI, 2.3-211.0) and breast abscess (RR, 51.6; 95% CI, 4.7-571.0) were associated with late transmission (occurring >2 months postpartum). Use of methods that decrease infant exposure to HIV-1 in maternal genital secretions or breast milk may enhance currently recommended perinatal HIV-1 interventions.

Hormonal Contraception, Sexually Transmitted Diseases, and Risk of Heterosexual Transmission of Human Immunodeficiency Virus Type 1

To examine associations between method of contraception, sexually transmitted diseases (STDs), and incident human immunodeficiency virus type 1 (HIV-1) infection, a prospective observational cohort study was done among female sex workers attending a municipal STD clinic in Mombasa, Kenya. Demographic and behavioral factors significantly associated with HIV-1 infection included type of workplace, condom use, and parity. In multivariate models, vulvitis, genital ulcer disease, vaginal discharge, and Candida vaginitis were significantly associated with HIV-1 seroconversion. Women who used depo medroxyprogesterone acetate (DMPA) had an increased incidence of HIV-1 infection (hazard ratio [HR], 2.2; 95% confidence interval [CI], 1.4-3.4). In a multivariate model controlling for demographic and exposure variables and biologic covariates, the adjusted HR for HIV-1 infection among DMPA users was 2.0 (CI, 1.3-3.1). There was a trend for an association between use of high-dose oral contraceptive pills and HIV-1 acquisition (HR, 2.6; CI, 0.8-8.5).

Longitudinal Analysis of Human Immunodeficiency Virus Type 1 RNA in Breast Milk and of Its Relationship to Infant Infection and Maternal Disease

Transmission of human immunodeficiency virus type 1 (HIV-1) via breast-feeding can occur throughout lactation. Defining both fluctuation in breast-milk virus level over time and how breast-milk virus correlates with mother-to-child transmission is important for establishing effective interventions. We quantified breast-milk HIV-1 RNA levels in serial samples collected from 275 women for up to 2 years after delivery. Higher maternal plasma virus load, lower maternal CD4 T cell count, and detection of HIV-1 DNA in maternal genital secretions were significantly associated with elevated breast-milk HIV-1 RNA. Within women who breast-fed, median virus load in colostrum/early milk was significantly higher than that in mature breast milk collected 14 days after delivery (P< or =.004). Breast-feeding mothers who transmitted HIV-1 to their infants had both significantly higher breast-milk viral RNA throughout lactation and more-consistent viral shedding, compared with mothers who did not transmit HIV-1. In breast-feeding women, a 2-fold-increased risk of transmission was associated with every 10-fold increase in breast-milk virus load (95% confidence interval, 1.3-3.0; P<.001). These results indicate that the risk of infant infection from breast-feeding is influenced by breast-milk virus load, which is highest early after delivery.

The Effect of Treatment of Vaginal Infections on Shedding of Human Immunodeficiency Virus Type 1

To assess the effect of treatment of vaginal infections on vaginal shedding of cell-free human immunodeficiency virus type 1 (HIV-1) and HIV-1-infected cells, HIV-1-seropositive women were examined before and after treatment of Candida vulvovaginitis, Trichomonas vaginitis, and bacterial vaginosis. For Candida (n=98), vaginal HIV-1 RNA decreased from 3.36 to 2.86 log(10) copies/swab (P<.001), as did the prevalence of HIV-1 DNA (36% to 17%; odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3-6.5). For Trichomonas vaginitis (n=55), HIV-1 RNA decreased from 3.67 to 3.05 log(10) copies/swab (P<.001), but the prevalence of HIV-1 DNA remained unchanged (22%-25%; OR, 0.8; 95% CI, 0.3-2.2). For bacterial vaginosis (n=73), neither the shedding of HIV-1 RNA (from 3.11 to 2.90 log(10) copies/swab; P=.14) nor the prevalence of DNA (from 21% to 23%; OR, 0.8; 95% CI, 0.3-2.0) changed. Vaginal HIV-1 decreased 3.2- and 4.2-fold after treating Candida and Trichomonas, respectively. These data suggest that HIV-1 transmission intervention strategies that incorporate diagnosis and treatment of these prevalent infections warrant evaluation.

Gender differences in HIV-1 diversity at time of infection

To develop an HIV-1 vaccine with global efficacy, it is important to identify and characterize the viruses that are transmitted, particularly to individuals living in areas of high incidence. Several studies have shown that virus from the blood of acutely infected adults was homogeneous, even when the virus population in the index case was genetically diverse. In contrast to those results with mainly male cohorts in America and Europe, in several cases a heterogeneous virus population has been found early in infection in women in Africa. Thus, we more closely compared the diversity of transmitted HIV-1 in men and women who became infected through heterosexual contact. We found that women from Kenya were often infected by multiple virus variants, whereas men from Kenya were not. Moreover, a heterogeneous virus was present in the women before their seroconversion, and in each woman it was derived from a single index case, indicating that diversity was most likely to be the result of transmission of multiple variants. Our data indicate that there are important differences in the transmitted virus populations in women and men, even when cohorts from the same geographic region who are infected with the same subtypes of HIV-1 are compared.

Association of Levels of HIV-1—Infected Breast Milk Cells and Risk of Mother-to-Child Transmission

Understanding how the level of human immunodeficiency virus type 1 (HIV-1)-infected breast milk cells (BMCs) affects HIV transmission via breast-feeding can shed light on the mechanism of infection and aid in establishing effective interventions. The proportion of infected cells to total cells was measured in serial breast milk samples collected from 291 HIV-1-infected women in Nairobi, Kenya, by use of real-time DNA polymerase chain reaction amplification of BMCs. The number of infected BMCs per million cells was associated with levels of cell-free viral RNA in breast milk (R=.144; P=.032), levels of cell-free virus in blood plasma (R=.365; P<.001), and the detection of proviral DNA in cervical and vaginal secretions (P<.001 and P = .030, respectively). The number of infected BMCs per million cells was lower in colostrum or early milk than in mature milk (P<.001). Previous studies demonstrated that the concentration of BMCs varies throughout lactation, and we used these data to transform infected BMCs per million cells to infected BMCs per milliliter. The estimated concentration of infected BMCs per milliliter was higher in colostrum or early milk than in mature milk (P<.001). Each log10 increase in infected BMCs per milliliter was associated with a 3.19-fold-increased risk of transmission (P=.002), after adjustment for cell-free virus in plasma (hazard ratio [HR], 2.09; P=.03) and breast milk (HR, 1.01; P=1.00). This suggests that infected BMCs may play a more important role in transmission of HIV via breast-feeding than does cell-free virus.

HIV-1 subtypes and male-to-female transmission in Thailand

We examined the risk factors for heterosexual transmission of HIV in a case-control study of couples in Thailand. 90 HIV-positive men and their regular sex partners were enrolled at the immune clinic, Chulalongkorn Hospital, where 92% of male index cases had HIV-1 serotype A (subtype E). Most index cases had acquired HIV through sexual intercourse. 95 couples were enrolled at 15 detoxification clinics, where 79% of them had HIV-1 serotype B (subtype B). Most men had acquired HIV through injecting drug use (IDU).