Robin L. Broadhead

Bacterial vaginosis and disturbances of vaginal flora : association with increased acquisition of HIV

Background:Cross-sectional studies suggest an association between bacterial vaginosis (BV) and HIV-1 infection. However, an assessment of a temporal effect was not possible. Objectives:To determine the association of BV and other disturbances of vaginal flora with HIV seroconversion among pregnant and postnatal women in Malawi, Africa. Design:Longitudinal follow-up of pregnant and postpartum women. Methods:Women attending their first antenatal care visit were screened for HIV after counselling and obtaining informed consent. HIV-seronegative women were enrolled and followed during pregnancy and after delivery. These women were again tested for HIV at delivery and at 6-monthly visits postnatally. Clinical examinations and collection of laboratory specimens (for BV and sexually transmitted diseases) were conducted at screening and at the postnatal 6-monthly visits. The diagnosis of BV was based on clinical criteria. Associations of BV and other risk factors with HIV seroconversion, were examined using contingency tables and multiple logistic regression analyses on antenatal data, and Kaplan–Meier proportional hazards analyses on postnatal data. Results:Among 1196 HIV-seronegative women who were followed antenatally for a median of 3.4 months, 27 women seroconverted by time of delivery. Postnatally, 97 seroconversions occurred among 1169 seronegative women who were followed for a median of 2.5 years. Bacterial vaginosis was significantly associated with antenatal HIV seroconversion (adjusted odds ratio = 3.7) and postnatal HIV seroconversion (adjusted rate ratio = 2.3). There was a significant trend of increased risk of HIV seroconversion with increasing severity of vaginal disturbance among both antenatal and postnatal women. The approximate attributable risk of BV alone was 23% for antenatal HIV seroconversions and 14% for postnatal seroconversions. Conclusions:This prospective study suggests that progressively greater disturbances of vaginal flora, increase HIV acquisition during pregnancy and postnatally. The screening and treating of women with BV could restore normal flora and reduce their susceptibility to HIV.

Human Immunodeficiency Virus Load in Breast Milk, Mastitis, and Mother-to-Child Transmission of Human Immunodeficiency Virus Type 1

Human immunodeficiency virus (HIV) type 1 load in breast milk and mastitis were examined as risk factors for vertical transmission of HIV-1. Six weeks after delivery, HIV-1 load and sodium (an indicator of mastitis) were measured in breast milk from 334 HIV-1-infected women in Malawi. Median breast milk HIV-1 load was 700 copies/mL among women with HIV-1-infected infants versus undetectable (<200 copies/mL) among those with uninfected infants, respectively (P<. 0001). Elevated breast milk sodium levels consistent with mastitis occurred in 16.4% of HIV-1-infected women and were associated with increased vertical transmission of HIV-1 (P<.0001). Median breast milk HIV-1 load was 920 copies/mL among women with versus undetectable among those without elevated breast milk sodium levels, respectively (P<.0001). Mastitis and breast milk HIV-1 load may increase the risk of vertical transmission of HIV-1 through breast-feeding.

Increased prevalence of malaria in HIV-infected pregnant women and its implications for malaria control.

Summary objectives  To examine in pregnant women the relationship between HIV infection and malaria prevalence and to determine, in relation to HIV infection, the effectiveness of sulphadoxine‐pyrimethamine in clearing P. falciparum infection.

Rotavirus G and P types in children with acute diarrhea in Blantyre, Malawi, from 1997 to 1998: predominance of novel P[6]G8 strains.

One hundred rotavirus strains detected in children with acute diarrhea in Blantyre, Malawi, between July 1997 and January 1998 were characterized for G (VP7) and P (VP4) types by using multiplex, heminested, reverse transcription–polymerase chain reaction. A novel P[6]G8 rotavirus strain was identified in 42% of the specimens. The remaining strains comprised P[8]G3 (20%), P[6]G3 (10%), P[4]G8 (9%), P[6]G9 (3%), P[8]G4 (2%), P[6]G4 (2%), and P[4]G3 (1%). Rotavirus strains with mixed G or P types were identified in 2% of the specimens. Nine percent of the strains were nontypeable with the primers used. The P[6] genotype was identified in 57% of strains overall. This first description of serotype G8 rotavirus as a predominant strain has important implications for vaccine development in Africa. The finding of novel P/G combinations (P[6]G8 and P[4]G8) highlights the extraordinary diversity of rotaviruses in some countries. J. Med. Virol. 57:308–312, 1999.

An evaluation of the effects of intermittent sulfadoxine-pyrimethamine treatment in pregnancy on parasite clearance and risk of low birthweight in rural Malawi

The prevalence of infection with malarial parasites and the incidence of anaemia and delivery of infants with low birthweight (LBW) were investigated in 575 Malawian mothers who received one, two or three doses of sulfadoxine-pyrimethamine (SP) during pregnancy. All the subjects were enrolled at their first antenatal visit and all delivered at hospital. The prevalence of Plasmodium falciparum infection at first antenatal visit was 35.3% in primigravidae and 13.6% in multigravidae (P < 0.001). Mean haemoglobin concentration was significantly lower in primigravidae than in multigravidae (8.8 v. 9.5 g/dl; P < 0.001). Of the 233 women tested for HIV infection, 18.8% of the primigravidae and 23.7% of the multigravidae were seropositive. At delivery, there was no significant difference in parasite prevalence in peripheral or placental blood between women who had received one or two antenatal doses of SP. The multigravidae who had received two doses of SP had higher mean haemoglobin concentrations than those who had received just one (P = 0.009) [this difference was not seen in the primigravidae (P = 0.92)]. However, linear regression analysis indicated that the haematinic supplements given to the subjects contributed more to this increase in haemoglobin concentration than the SP. The mean birthweights were higher, and incidence of LBW lower in babies born to primi-and multi-gravidae who had received two or three doses of SP treatment than those seen in babies born to women who had had just one dose (P < 0.03 for each). The odds ratio for LBW in primigravidae compared with multigravidae decreased from 3.2 to 1.0 as the number of SP doses increased from one to three. The benefit of three doses (compared with none) was equivalent to the population-attributable risk of LBW in primigravidae being reduced from 34.6% to 0%. Subjects who were seropositive for HIV were twice as likely to give birth to LBW babies as the other subjects. The use of SP was not associated with maternal side-effects or perinatal complications. The present results indicate that multiple doses of SP taken during pregnancy will lead to a highly significant reduction in the incidence of LBW in infants born to primigravidae, even if the women have HIV infections. This reduction is observable even when parasite prevalence at delivery is high because of re-infections in late pregnancy; reduction in parasite prevalence earlier in pregnancy, as the result of SP treatment, leads to improved foetal growth.

Short postexposure prophylaxis in newborn babies to reduce mother-to-child transmission of HIV-1: NVAZ randomised clinical trial

BACKGROUND In sub-Saharan Africa, most women present late for delivery with unknown HIV status, which limits the use of intrapartum nevirapine to prevent mother-to-child transmission of HIV. We aimed to determine whether post-exposure prophylaxis of nevirapine plus zidovudine given to babies only reduced transmission of HIV more than did a regimen of nevirapine alone. METHODS We randomly assigned 1119 babies of Malawian women with HIV-1 who presented late (ie, within 2 h of expected delivery) to either nevirapine alone or nevirapine and zidovudine. Both drugs were given immediately after birth: one dose of nevirapine (2 mg/kg weight) was given as a single dose; babies in the nevirapine plus zidovudine group also received zidovudine twice daily for 1 week (4 mg/kg weight). Infant HIV infection was determined at birth and at 6-8 weeks. Primary outcome was HIV infection in babies at 6-8 weeks in those not infected at birth. Analysis was by intention to treat. FINDINGS The overall rate of mother-to-child transmission at 6-8 weeks was 15.3% in 484 babies who received nevirapine and zidovudine and 20.9% in 468 babies who received nevirapine only (p=0.03). At 6-8 weeks, in babies who were HIV negative at birth, 34 (7.7%) babies who had nevirapine and zidovudine and 51 (12.1%) who received nevirapine only were infected (p=0.03)-a protective efficacy of 36%. This finding remained after controlling for maternal viral load and other factors at baseline. Adverse events were mild and of similar frequency in the two groups. INTERPRETATION Postexposure prophylaxis can offer protection against HIV infection to babies of women who missed opportunities to be counselled and tested before or during pregnancy. The nevirapine and zidovudine regimen is safe and easy to implement.

Effect of cleansing the birth canal with antiseptic solution on maternal and newborn morbidity and mortality in Malawi: clinical trial.

Abstract Objective: To determine if cleansing the birth canal with an antiseptic at delivery reduces infections in mothers and babies postnatally. Design: Clinical trial; two months of no intervention were followed by three months of intervention and a final month of no intervention. Setting: Queen Elizabeth Central Hospital (tertiary care urban hospital), Blantyre, Malawi. Subjects: A total of 6965 women giving birth in a six month period and their 7160 babies. Intervention: Manual wipe of the maternal birth canal with a 0.25% chlorhexidine solution at every vaginal examination before delivery. Babies born during the intervention were also wiped with chlorhexidine. Main outcome measures: Effects of the intervention on neonatal and maternal morbidity and mortality. Results: 3635 women giving birth to 3743 babies were enrolled in the intervention phase and 3330 women giving birth to 3417 babies were enrolled in the non-intervention phase. There were no adverse reactions related to the intervention among the mothers or their children. Among infants born in the intervention phase, overall neonatal admissions were reduced (634/3743 (16.9%) v 661/3417 (19.3%), P<0.01), as were admissions for neonatal sepsis (7.8 v 17.9 per 1000 live births, P<0.0002), overall neonatal mortality (28.6 v 36.9 per 1000 live births, P<0.06), and mortality due to infectious causes (2.4 v 7.3 per 1000 live births, P<0.005). Among mothers receiving the intervention, admissions related to delivery were reduced (29.4 v 40.2 per 1000 deliveries, P<0.02), as were admissions due to postpartum infections (1.7 v 5.1 per 1000 deliveries, P=0.02) and duration of hospitalisation (Wilcoxon P=0.008). Conclusions: Cleansing the birth canal with chlorhexidine reduced early neonatal and maternal postpartum infectious problems. The safety, simplicity, and low cost of the procedure suggest that it should be considered as standard care to lower infant and maternal morbidity and mortality.

Rotavirus strain diversity in Blantyre, Malawi, from 1997 to 1999.

ABSTRACT In a 2-year study of viral gastroenteritis in children in Blantyre, Malawi, the diversity of rotavirus strains was investigated by using electropherotyping, reverse transcription-PCR amplification of the VP7 and VP4 genes (G and P genotyping), and nucleotide sequencing. Of 414 rotavirus strains characterized, the following strain types were identified: P[8], G1 (n = 111; 26.8%); P[6], G8 (n = 110; 26.6%); P[8], G3 (n = 93; 22.5%); P[4], G8 (n = 31; 7.5%); P[8], G4 (n = 21; 5.1%); P[6], G3 (n = 12; 2.9%); P[6], G1 (n = 7; 1.7%); P[6], G9 (n = 3; 0.7%); P[6], G4 (n = 3; 0.7%); P[4], G3 (n = 1; 0.2%); and mixed (n = 15; 3.6%). While all strains could be assigned a G type, seven strains (1.7%) remained P nontypeable. The majority of serotype G8 strains and all serotype G9 strains had short electropherotype profiles. All remaining typeable strains had long electropherotypes. Divergent serotype G1 rotaviruses, which contained multiple base substitutions in the 9T-1 primer binding site, were commonly identified in the second year of surveillance. Serotype G2 was not identified. Overall, G8 was the most frequently identified VP7 serotype (n = 144; 34.8%) and P[8] was the most frequently detected VP4 genotype (n = 227; 54.8%). Partial sequence analysis of the VP4 gene of genotype P[8] rotaviruses identified three distinct clusters, which predominantly (but not exclusively) comprised strains belonging to a distinct VP7 serotype (G1, G3, or G4). As a result of mutations in the 1T-1 primer binding site, strains belonging to each cluster required a separate primer for efficient typing. One cluster, represented by P[8], G4 strain OP354, was highly divergent from the established Wa and F45 VP4 P[8] lineages. As is the case for some other countries, the diversity of rotaviruses in Malawi implies that rotavirus vaccines in development will need to protect against a wider panel of serotypes than originally envisioned.

Molecular Epidemiology of Cryptosporidiosis in Children in Malawi

ABSTRACT: Few studies have examined the molecular epidemiology of cryptosporidiosis in developing countries. In this study, DNA of 69 microscopy‐positive human fecal samples collected from Malawi were examined by multilocus genetic analyses. From 43, 27 and 28 of the samples, the SSU rRNA, 70 kDa heat shock protein (HSP70) and 60 kDa glycoprotein (GP60) genes, respectively, were successfully PCR‐amplified. Restriction analysis of the SSU PCR products showed that 41 of the 43 PCR‐positive samples had C. hominis and 2 had C. parvum. Sequence analysis of the HSP70 and GP60 gene contirmed the species identification by SSU rRNA PCR‐RFLP analysis, but also revealed high intraspecific variations. Altogether, six HSP70 subtypes and six GP60 subtypes (belonging to lour subtype alleles) of C. hominis were found. Linkage diseyuilibrum analysis of the two genetic loci showed possible intraspecitic recombination. Thus, cryptosporidiosis in the study area was largely caused by anthroponotic transmission. The high intraspecitic variation and existence of genetic recombination were probably results of high transmission of cryptosporidiosis in this area.

Promiscuous expression of Epstein-Barr virus genes in Burkitt's lymphoma from the central African country Malawi

Primary BL in Malawian children has a very high frequency association, approaching 100%, with the human herpesvirus EBV. A detailed study carried out on viral gene expression in these tumours, using both fresh material and methanol‐fixed FNAs, showed, contrary to prediction, that most belong to a variant “class II” latency category, with lytic cycle–related genes also expressed. That is, in addition to EBNA1 expression, membrane proteins (LMP1/2A), immediate early (BZLF1) and early (IR2 and IR4) genes, a putative viral oncogene (BARF1), CST (BART) antisense transcripts and the viral bcl‐2 homologue are expressed in a high proportion of the BLs. Most, but not all, express the small viral (EBER) RNAs. Two other significant observations were made: (i) in addition to expression of cellular cytokine (IL‐10) transcripts in all tumours investigated, the normally silent viral IL‐10 homologue was expressed in some tumours; (ii) whereas EBNA1 expression from its restricted Qp promoter was generally observed, the nonrestricted Cp/Wp promoter was also active in some tumours. Viral gene expression in the Malawian [endemic (e)] BLs appears to be more promiscuous than predicted from other studies, but expression accords with the cytopathologic picture of eBLs as a rapidly proliferating cell population accompanied by considerable necrosis, and a clinically diverse disease. A small‐scale study of relapse Malawian BLs revealed a different picture of viral association, more akin to systemic BL than eBL, where EBV appears to be absent or present only at very low levels. The significance of these findings is considered.