Ambrose O Misore

Kenya Medical Research Institute, Nairoba, Nairobi Area, Kenya

Are you Ambrose O Misore?

Claim your profile

Publications (24)118.49 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Effective strategies are needed for the prevention of mother-to-child HIV transmission (PMTCT) in resource-limited settings. The Kisumu Breastfeeding Study was a single-arm open label trial conducted between July 2003 and February 2009. The overall aim was to investigate whether a maternal triple-antiretroviral regimen that was designed to maximally suppress viral load in late pregnancy and the first 6 mo of lactation was a safe, well-tolerated, and effective PMTCT intervention. HIV-infected pregnant women took zidovudine, lamivudine, and either nevirapine or nelfinavir from 34-36 weeks' gestation to 6 mo post partum. Infants received single-dose nevirapine at birth. Women were advised to breastfeed exclusively and wean rapidly just before 6 mo. Using Kaplan-Meier methods we estimated HIV-transmission and death rates from delivery to 24 mo. We compared HIV-transmission rates among subgroups defined by maternal risk factors, including baseline CD4 cell count and viral load. Among 487 live-born, singleton, or first-born infants, cumulative HIV-transmission rates at birth, 6 weeks, and 6, 12, and 24 mo were 2.5%, 4.2%, 5.0%, 5.7%, and 7.0%, respectively. The 24-mo HIV-transmission rates stratified by baseline maternal CD4 cell count <500 and ≥500 cells/mm(3) were 8.4% (95% confidence interval [CI] 5.8%-12.0%) and 4.1% (1.8%-8.8%), respectively (p = 0.06); the corresponding rates stratified by baseline maternal viral load <10,000 and ≥10,000 copies/ml were 3.0% (1.1%-7.8%) and 8.7% (6.1%-12.3%), respectively (p = 0.01). None of the 12 maternal and 51 infant deaths (including two second-born infants) were attributed to antiretrovirals. The cumulative HIV-transmission or death rate at 24 mo was 15.7% (95% CI 12.7%-19.4%). This trial shows that a maternal triple-antiretroviral regimen from late pregnancy through 6 months of breastfeeding for PMTCT is safe and feasible in a resource-limited setting. These findings are consistent with those from other trials using maternal triple-antiretroviral regimens during breastfeeding in comparable settings.
    PLoS Medicine 03/2011; 8(3):e1001015. · 15.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To estimate HIV prevalence and characterize risk factors among young adults in Asembo, rural western Kenya. Community-based cross-sectional survey. From a demographic surveillance system, we selected a random sample of residents aged 13-34 years, who were contacted at home and invited to a nearby mobile study site. Consent procedures for non-emancipated minors required assent and parental consent. From October 2003 - April 2004, consenting participants were interviewed on risk behavior and tested for HIV and HSV-2. HIV voluntary counseling and testing was offered. Of 2606 eligible residents, 1822 (70%) enrolled. Primary reasons for refusal included not wanting blood taken, not wanting to learn HIV status, and partner/parental objection. Females comprised 53% of 1762 participants providing blood. Adjusted HIV prevalence was 15.4% overall: 20.5% among females and 10.2% among males. HIV prevalence was highest in women aged 25-29 years (36.5%) and men aged 30-34 years (41.1%). HSV-2 prevalence was 40.0% overall: 53% among females, 25.8% among males. In multivariate models stratified by gender and marital status, HIV infection was strongly associated with age, higher number of sex partners, widowhood, and HSV-2 seropositivity. Asembo has extremely high HIV and HSV-2 prevalence, and probable high incidence, among young adults. Further research on circumstances around HIV acquisition in young women and novel prevention strategies (vaccines, microbicides, pre-exposure prophylaxis, HSV-2 prevention, etc.) are urgently needed.
    PLoS ONE 02/2009; 4(7):e6470. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Consecutive outbreaks of acute aflatoxicosis in Kenya in 2004 and 2005 caused > 150 deaths. In response, the Centers for Disease Control and Prevention and the World Health Organization convened a workgroup of international experts and health officials in Geneva, Switzerland, in July 2005. After discussions concerning what is known about aflatoxins, the workgroup identified gaps in current knowledge about acute and chronic human health effects of aflatoxins, surveillance and food monitoring, analytic methods, and the efficacy of intervention strategies. The workgroup also identified public health strategies that could be integrated with current agricultural approaches to resolve gaps in current knowledge and ultimately reduce morbidity and mortality associated with the consumption of aflatoxin-contaminated food in the developing world. Four issues that warrant immediate attention were identified: a) quantify the human health impacts and the burden of disease due to aflatoxin exposure; b) compile an inventory, evaluate the efficacy, and disseminate results of ongoing intervention strategies; c) develop and augment the disease surveillance, food monitoring, laboratory, and public health response capacity of affected regions; and d) develop a response protocol that can be used in the event of an outbreak of acute aflatoxicosis. This report expands on the workgroup's discussions concerning aflatoxin in developing countries and summarizes the findings.
    Environmental Health Perspectives 12/2006; 114(12):1898-903. · 7.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: During January-June 2004, an aflatoxicosis outbreak in eastern Kenya resulted in 317 cases and 125 deaths. We conducted a case-control study to identify risk factors for contamination of implicated maize and, for the first time, quantitated biomarkers associated with acute aflatoxicosis. We administered questionnaires regarding maize storage and consumption and obtained maize and blood samples from participants. We recruited 40 case-patients with aflatoxicosis and 80 randomly selected controls to participate in this study. EVALUATIONS/MEASUREMENTS: We analyzed maize for total aflatoxins and serum for aflatoxin B1-lysine albumin adducts and hepatitis B surface antigen. We used regression and survival analyses to explore the relationship between aflatoxins, maize consumption, hepatitis B surface antigen, and case status. Homegrown (not commercial) maize kernels from case households had higher concentrations of aflatoxins than did kernels from control households [geometric mean (GM) = 354.53 ppb vs. 44.14 ppb; p = 0.04]. Serum adduct concentrations were associated with time from jaundice to death [adjusted hazard ratio = 1.3; 95% confidence interval (CI), 1.04-1.6]. Case patients had positive hepatitis B titers [odds ratio (OR) = 9.8; 95% CI, 1.5-63.1] more often than controls. Case patients stored wet maize (OR = 3.5; 95% CI, 1.2-10.3) inside their homes (OR = 12.0; 95% CI, 1.5-95.7) rather than in granaries more often than did controls. Aflatoxin concentrations in maize, serum aflatoxin B1-lysine adduct concentrations, and positive hepatitis B surface antigen titers were all associated with case status. The novel methods and risk factors described may help health officials prevent future outbreaks of aflatoxicosis.
    Environmental Health Perspectives 01/2006; 113(12):1779-83. · 7.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To improve uptake in a program to prevent mother-to-child HIV transmission and describe lessons relevant for prevention of mother-to-child transmission programs in resource-poor settings. Implementation of a pilot project that evaluates approaches to increase program uptake at health facility level at New Nyanza Provincial General Hospital, a public hospital in western Kenya, an area with high HIV prevalence. Client flow was revised to integrate counseling, HIV testing, and dispensing of single-dose nevirapine into routine antenatal services. The number of facilities providing PMCT services was expanded to increase district-wide coverage. Main outcome measures were uptake of counseling, HIV testing, nevirapine, and estimated program impact. Uptake of counseling and testing improved from 55 to 68% (P < 0.001), nevirapine uptake from 57% to 70% (P < 0.001), and estimated program impact from 15% to 23% (P = 0.03). Aggregate reports compare well with computer-entered data. Addressing institutional factors can improve uptake, but expected program impact remains low for several reasons, including relatively low efficacy of the intervention and missed opportunities in the labor room.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 12/2005; 40(3):344-9. · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In April 2004, one of the largest aflatoxicosis outbreaks occurred in rural Kenya, resulting in 317 cases and 125 deaths. Aflatoxin-contaminated homegrown maize was the source of the outbreak, but the extent of regional contamination and status of maize in commercial markets (market maize) were unknown. We conducted a cross-sectional survey to assess the extent of market maize contamination and evaluate the relationship between market maize aflatoxin and the aflatoxicosis outbreak. We surveyed 65 markets and 243 maize vendors and collected 350 maize products in the most affected districts. Fifty-five percent of maize products had aflatoxin levels greater than the Kenyan regulatory limit of 20 ppb, 35% had levels > 100 ppb, and 7% had levels > 1,000 ppb. Makueni, the district with the most aflatoxicosis case-patients, had significantly higher market maize aflatoxin than did Thika, the study district with fewest case-patients (geometric mean aflatoxin = 52.91 ppb vs. 7.52 ppb, p = 0.0004). Maize obtained from local farms in the affected area was significantly more likely to have aflatoxin levels > 20 ppb compared with maize bought from other regions of Kenya or other countries (odds ratio = 2.71; 95% confidence interval, 1.12-6.59). Contaminated homegrown maize bought from local farms in the affected area entered the distribution system, resulting in widespread aflatoxin contamination of market maize. Contaminated market maize, purchased by farmers after their homegrown supplies are exhausted, may represent a source of continued exposure to aflatoxin. Efforts to successfully interrupt exposure to aflatoxin during an outbreak must consider the potential role of the market system in sustaining exposure.
    Environmental Health Perspectives 12/2005; 113(12):1763-7. · 7.26 Impact Factor
  • International AIDS Conference; 07/2004
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In 1998, the Kenyan Ministry of Health introduced intermittent preventive treatment (IPT) with sulphadoxine-pyrimethamine (SP), one treatment dose in the second trimester (16-27 weeks) and one treatment dose between 28 and 34 weeks of gestational age, for the control of malaria in pregnancy. We evaluated the coverage and determinants of receipt of IPT after its introduction in the Provincial Hospital in Kisumu, western Kenya. Information on the use of IPT in pregnancy was collected from women who attended the antenatal clinic (ANC) and delivered in the same hospital. In exit interviews, we assessed patterns of IPT use in the ANC. Of 1498 women who delivered between June 1999 and June 2000, 23.7%, 43.4% and 32.9% received > or =2, 1 or no dose of SP, respectively. Late first ANC attendance was the most important factor contributing to incomplete IPT; 45% of the women started attending ANC in the third trimester. More women received at least one tetanus toxoid immunization than at least one dose of IPT (94%vs. 67%, P < 0.05). In exit interviews, 74% correctly associated IPT with treatment of malaria; however, knowledge on the need for the second dose was poor. Three per cent of the administrations were given despite contraindications. The agreement between gestational age by date of last menstrual period and by palpation was low (kappa = 0.1). Education of pregnant women and ANC staff to increase earlier attendance for ANC has the potential to substantially increase the proportion of women receiving two doses of IPT with SP.
    Tropical Medicine & International Health 06/2004; 9(5):630-7. · 2.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To monitor the effectiveness of intermittent preventive treatment (IPT) with sulphadoxine-pyrimethamine (SP) for the control of malaria in pregnancy at delivery in the Provincial Hospital in Kisumu, Kenya, and to assess the effect of IPT in participants in a cohort study. Between June 1999 and June 2000, information on IPT and birth outcome was collected in 2302 consecutive deliveries. A group of 889 women, who were enrolled in a cohort to assess the interaction between malaria and HIV, were analysed separately because of the enrollment criteria and different access to health care. The prevalence of placental malaria was 13.8% and of low birthweight (LBW) was 12.2%. In multivariable analysis, IPT (> or =1 dose of SP) was associated with a reduction in placental malaria and LBW [adjusted odds ratio (OR) 0.56, 95% confidence interval (CI) 0.39-0.83 and OR 0.65, 95% CI 0.45-0.95, respectively]. An adjusted mean increase in birthweight of 61 g was seen (95% CI 22-101 g) for each increment in number of SP doses (> or =2 doses grouped together). IPT was associated with a reduction in placental malaria in HIV-seronegative women (OR 0.49, 95% CI 0.28-0.86) but this was not significant among HIV-seropositive women (OR 0.45, 95% CI 0.20-1.05). A significant effect on birthweight could not be detected among participants in the HIV-cohort. This evaluation confirms that IPT with SP is effective in reducing placental malaria and LBW. It will be important to increase coverage of IPT and to extend IPT to antenatal clinics in peri-urban and rural areas.
    Tropical Medicine & International Health 04/2004; 9(3):351-60. · 2.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine whether maternal placental malaria is associated with an increased risk for perinatal mother-to-child HIV transmission (MTCT), we studied HIV-positive women in western Kenya. We enrolled 512 mother-infant pairs; 128 (25.0%) women had placental malaria, and 102 (19.9%) infants acquired HIV perinatally. Log10 HIV viral load and episiotomy or perineal tear were associated with increased perinatal HIV transmission, whereas low-density placental malaria (<10,000 parasites/mL) was associated with reduced risk (adjusted relative risk [ARR] 0.4). Among women dually infected with malaria and HIV, high-density placental malaria (>10,000 parasites/mL) was associated with increased risk for perinatal MTCT (ARR 2.0), compared to low-density malaria. The interaction between placental malaria and MTCT appears to be variable and complex: placental malaria that is controlled at low density may cause an increase in broad-based immune responses that protect against MTCT; uncontrolled, high-density malaria may simultaneously disrupt placental architecture and generate substantial antigen stimulus to HIV replication and increase risk for MTCT.
    Emerging infectious diseases 04/2004; 10(4):643-52. · 5.99 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Little is known about the impact of HIV-1 group M subtypes on mother-to-child transmission (MTCT) of HIV-1 in African settings where multiple HIV-1 group M subtypes are co-circulating. To assess the role of subtype variation on MTCT. HIV-1-infected women attending an antenatal clinic in western Kenya were enrolled for a prospective study (1996-2000) of MTCT. HIV-1 subtype analysis of p24gag and gp41env identified potential recombinants, and their role in MTCT was determined. Among 414 women for whom HIV-1 subtype and HIV transmission status were available, MTCT occurred in 80 (19.3%). MTCT rates were higher among women with subtype D compared with subtype A in either the gp41 region [31.6 versus 16.1%, relative risk (RR) 2.0, P=0.002] or p24 region (29.9 versus 18.0%, RR 1.7, P=0.02). Discordant subtype combinations were identified in 103 of the women (25.9%), and were associated with higher rates of MTCT (28.2 versus 17.0%, RR 1.7, P=0.01). In multivariate analysis, women with subtype combinations D/D, D/A, and A/D had an increased risk of MTCT (adjusted odds ratios 3.5, 2.5, 6.2; P=0.005, 0.05, and 0.0003, respectively) compared with A/A women after adjustment for maternal HIV viral load, placental malaria infection, episiotomy or perineal tear, and low birthweight. MTCT appears to be more common among mothers infected with subtype D compared with subtype A. Such differences in MTCT frequency may be caused by altered cellular tropism for placental cell types.
    AIDS 08/2003; 17(11):1667-74. · 6.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To study the importance of HIV infection for malaria in pregnancy in Kisumu, Kenya. Healthy women with an uncomplicated pregnancy of 32 weeks or more attending the prenatal clinic in the Provincial Hospital between June 1996 and March 1999 were tested for HIV and malaria after consent had been obtained. For participating women who delivered in the same hospital, a blood smear of the mother and the placenta were obtained. In the third trimester, 5093 women consented to testing: the prevalence of malaria and HIV was 20.1 and 24.9%, respectively. Among the 2502 screened women who delivered in the hospital, the prevalence of HIV, peripheral parasitaemia and placental malaria was 24.5, 15.2, and 19.0%, respectively. Compared with HIV-seronegative women, HIV-seropositive women were more likely to be parasitaemic, to have higher parasite densities, and to be febrile when parasitaemic. Placental infections in HIV-seropositive women were more likely to be chronic, as indicated by the presence of moderate to heavy pigment depositions. When adjusted by age, the typical gravidity-specific pattern of malaria in pregnancy disappeared in HIV-seropositive women; HIV-seropositive primigravidae had a similar risk of malaria as HIV-seropositive multigravidae. The excess malaria attributable to HIV in the third trimester increased from 34.6% among HIV-seropositive primigravidae, to 41.5% among HIV-seropositive secundigravidae, and 50.7% among HIV-seropositive gravidae with three or more pregnancies. HIV infection alters patterns of malaria in pregnant women; in areas with both infections, all pregnant women should use malaria prevention.
    AIDS 04/2003; 17(4):595-603. · 6.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine the effect of dual infection with HIV and malaria on birth outcomes and maternal anaemia among women delivering at a large public hospital in Kisumu, western Kenya. Data on obstetric and neonatal characteristics, maternal and placental parasitaemia, and postpartum haemoglobin levels were collected from women enrolled in a cohort study of the interaction between malaria and HIV during pregnancy. Between 1996 and 1999, data were available from 2466 singleton deliveries. The maternal HIV seroprevalence was 24.3%, and at delivery 22.0% of the women had evidence of malaria. Low birthweight, preterm delivery (PTD), intrauterine growth retardation (IUGR) and maternal anaemia (haemoglobin < 8 g/dl) occurred in 4.6, 6.7, 9.8 and 13.8% of deliveries, respectively. Maternal HIV, in the absence of malaria, was associated with a 99 g (95% CI 52-145) reduction in mean birthweight among all gravidae. Malaria was associated with both IUGR and PTD, resulting in a reduction in mean birthweight of 145 g (95% CI 82-209) among HIV-seronegative and 206 g (95% CI 115-298) among HIV-seropositive primigravidae, but not among multigravidae. Both HIV and malaria were significant risk factors for postpartum maternal anaemia, and HIV-seropositive women with malaria were twice as likely to have anaemia than HIV-seronegative women with or without malaria. Women with dual infection are at particular risk of adverse birth outcomes. In areas with a moderate or high prevalence of HIV and malaria, all pregnant women should be the focus of malaria and anaemia control efforts to improve birth outcomes.
    AIDS 04/2003; 17(4):585-94. · 6.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The role of maternal and pediatric infection with human immunodeficiency virus type 1 (HIV-1) and malaria as risk factors for anemia was determined in a birth cohort of infants born to mothers participating in a study of the interaction between placental malaria and HIV infection, in Kisumu, Kenya. Between June 1996 and April 2000, 661 infants born to 467 HIV-seropositive and 194 HIV-seronegative mothers were monitored monthly from birth. At each visit a questionnaire was completed and a blood sample was collected for the determination of hemoglobin levels and detection of malaria and HIV. Anemia was common and increased from 13.6% at one month to 75% at six months and remained high throughout the second half of infancy. Placental malaria, infant malaria, and HIV infection of the infant were all associated with infant anemia in a multivariate model, adjusting for other co-variates found to be associated with infant anemia. The HIV-infected infants with malaria parasitemia had lower mean hemoglobin levels compared with HIV-uninfected infants, or HIV-infected infants without malaria, suggesting that HIV-infected infants are particularly vulnerable to the adverse consequences of malaria at this age. Early detection and prompt treatment of infant malaria and treatment of anemia as part of the study protocol failed to prevent most of the infants from becoming anemic. Although not proven effective in this study, micronutrient supplementation should be prospectively assessed in HIV-infected infants as a means of preventing anemia.
    The American journal of tropical medicine and hygiene 08/2002; 67(1):44-53. · 2.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess risk factors for malaria in pregnancy in Kisumu, western Kenya, we studied healthy women with an uncomplicated pregnancy of > or = 32 weeks attending the antenatal clinic in the Provincial Hospital. Between June 1996 and March 1999, malaria and human immunodeficiency virus (HIV) infection were examined in 5093 pregnant women: 20.1% of the women were parasitaemic and 24.9% were HIV-seropositive. 2502 women delivered in the hospital and a smear was obtained: the prevalence of placental malaria, maternal peripheral parasitaemia, and HIV infection was respectively 19.0%, 15.2% and 24.5%. HIV infection (risk ratio [RR] 1.58, 95% confidence interval [95% CI] 1.32-1.89), young age (< 21 years: RR 1.51, 95% CI 1.19-1.91), being a primigravidae (RR 1.41, 95% CI 1.05-1.88), a peri-urban residence (RR 1.50, 95% CI 1.21-1.88), and Luo ethnicity (RR 1.74, 95% CI 1.35-2.24) were risk factors for malaria at delivery. Use of sulfadoxine-pyrimethamine (SP), reported by 2.1% of the women, was a protective factor (RR 0.44, 95% CI 0.18-1.06). Results were similar in the third trimester. In this urban/peri-urban setting, preventing HIV infection, delaying the first pregnancy until after adolescence, and applying an effective antimalarial strategy such as intermittent therapy with SP will reduce the prevalence of malaria in pregnancy.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 01/2002; 96(6):586-92. · 1.82 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To assess risk factors for anemia in late pregnancy, we studied healthy pregnant women with a singleton uncomplicated pregnancy of > or = 32 weeks attending the prenatal clinic in the Provincial Hospital in Kisumu, Kenya. Between June 1996 and December 1998, 4,608 pregnant women had a blood sample collected for hemoglobin (Hb) measurement, malaria smear, and testing for human immunodeficiency virus (HIV). The mean +/- standard deviation of Hb was 9.58 +/- 1.8 g/dL; 21% had malaria in their blood; and 25% of the women were HIV seropositive. Plasmodium falciparum parasitemia was more common among HIV-seropositive women in all gravidities compared with HIV-seronegative women (risk ratio, 1.71; 95% confidence interval, 1.53-1.92). In a multivariate analysis, for primi- and secundigravidae women, the factors malaria, belonging to the Luo tribe, and HIV seropositivity were significantly associated with any anemia (Hb < 11 g/dL), and HIV seropositivity and documented fever were associated with severe anemia (Hb < 7 g/dL). In women of higher gravidities, HIV seropositivity was the only statistically significant factor associated with any anemia or with severe anemia. Asymptomatic HIV seropositivity is an important risk factor to be considered in the differential diagnosis of maternal anemia, independent of P. falciparum parasitemia.
    The American journal of tropical medicine and hygiene 11/2001; 65(5):623-30. · 2.53 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An association was demonstrated recently between elevated in vitro production of interferon (IFN)-gamma by intervillous blood mononuclear cells (IVBMCs) and protection against placental malaria (PM). Because human immunodeficiency virus (HIV)-infected pregnant women have increased susceptibility to PM, loss of the IFN-gamma response in these women may impair their ability to control PM. Measurement of cytokines in culture supernatants by ELISA revealed that IFN-gamma responses by HIV-positive IVBMCs were impaired, especially after malarial antigen stimulation. Interleukin (IL)-4 and IL-10 responses also were reduced in HIV-positive persons, the latter more so in HIV-positive, PM-positive persons. In contrast, tumor necrosis factor-alpha production generally was enhanced in PM-positive and HIV-positive persons. Overall, cytokine production was reduced in HIV-positive persons with CD4 T cell counts <500/microL, particularly in response to malarial antigen. Thus, HIV-mediated cytokine dysregulation and impairment of the protective IFN-gamma response may contribute to the increased susceptibility of HIV-positive pregnant women to malaria.
    The Journal of Infectious Diseases 09/2000; 182(3):960-4. · 5.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Our objective was to evaluate HIV prevalence and identify risk factors for HIV infection among women attending the antenatal clinic (ANC) at a large public hospital in Kisumu town, western Kenya. Between June 1996 and November 1997, in the context of a study to determine the effect of placental malaria on mother-to-child transmission of HIV in western Kenya, HIV-1 antibody testing was offered to women with a singleton uncomplicated pregnancy of > or =32 weeks' gestation attending the ANC. Women were interviewed using a structured questionnaire and had a fingerstick blood sample collected for haemoglobin (Hb), malaria smears, and HIV antibody testing. Overall HIV seroprevalence was 26.1% (743/2844) (95% confidence interval (CI): 24.5-27.7) and in bivariate evaluation was significantly associated with anaemia (Hb <11 g/dl) (risk ratio (RR) 1.8), malarial parasitaemia (RR 1.6), fever (axillary temperature > or =37.5 degrees C at screening) (RR 1.6), a history of being treated for either vaginal discharge (RR 1.5) or tuberculosis (RR 1.6), reported alcohol consumption (RR 1.6), being an unmarried multigravida (RR 2.2) or a history of the most recent child having died (RR 2.0). Poisson regression analysis for all women identified 5 significant factors independently associated with HIV seropositivity: anaemia (adjusted RR 1.7; 95% CI 1.3-2.0), malarial parasitaemia (adjusted RR 1.7; 95% CI 1.4-2.0), a history of being treated for vaginal discharge (adjusted RR 1.5; 95% CI 1.1-2.0), fever (adjusted RR 2.0; 95% CI 1.3-3.2) and reported alcohol consumption (adjusted RR 1.6; 95% CI 1.1-2.5). Multigravidae women whose most recent child had died were also more likely to be HIV seropositive (adjusted RR 1.9; 95% CI 1.7-2.8). Only 5.5% (156/2844) of the women had none of these risk factors, of whom 12% (18/156) were HIV(+). Even though the model containing the 5 identified factors fitted the data well (goodness-of-fit chi2=18.41, P=0.10), its collective capacity to predict HIV infection was poor; while 74% of the truly positive women were correctly predicted positive by the model, 52% of the truly negative women were misclassified. Among pregnant women attending the ANC in western Kenya, we were unable to identify a subgroup at risk of HIV infection using non-serological information, indicating that wherever possible universal access to voluntary HIV counselling and testing would be preferable to targeted screening.
    International Journal of STD & AIDS 07/2000; 11(6):393-401. · 1.00 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Severe anemia is one of the most lethal complications in children infected with Plasmodium falciparum. The pathogenesis of this anemia is not completely understood. Experimental data from malaria-infected humans and animal models suggest that uninfected red cells have a shortened life span. This study looked for changes in the red cell surfaces of children with severe malarial anemia that could explain this accelerated destruction. A prospective case-control study was conducted of children with severe P falciparum anemia (hemoglobin of 5 g/dL or lower) admitted to a large general hospital in western Kenya. Children with severe anemia were compared with children who had symptoms of uncomplicated malaria and with asymptomatic children. Cytofluorometry was used to quantify in vitro erythrophagocytosis and to measure red cell surface immunoglobulin G (IgG) and the complement regulatory proteins CR1, CD55, and CD59. Red cells from patients with severe anemia were more susceptible to phagocytosis and also showed increased surface IgG and deficiencies in CR1 and CD55 compared with controls. Red cell surface CD59 was elevated in cases of severe anemia compared with asymptomatic controls but not as compared with symptomatic controls. The surface of red cells of children with severe P falciparum anemia is modified by the deposition of IgG and alterations in the levels of complement regulatory proteins. These changes could contribute to the accelerated destruction of red cells in these patients by mechanisms such as phagocytosis or complement-mediated lysis. (Blood. 2000;95:1481-1486)
    Blood 03/2000; 95(4):1481-6. · 9.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In areas in which malaria is holoendemic, primigravidae and secundigravidae, compared with multigravidae, are highly susceptible to placental malaria (PM). The nature of gravidity-dependent immune protection against PM was investigated by measuring in vitro production of cytokines by placental intervillous blood mononuclear cells (IVBMC). The results demonstrated that interferon (IFN)-gamma may be a critical factor in protection against PM: production of this cytokine by PM-negative multigravid IVBMC was elevated compared with PM-negative primigravid and secundigravid and PM-positive multigravid cells. Low IFN-gamma responsiveness to malarial antigen stimulation, most evident in the latter group, was balanced by increased interleukin (IL)-4 production, suggesting that counter-regulation of these two cytokines may be a crucial determinant in susceptibility to PM. A counter-regulatory relationship between IL-10 and tumor necrosis factor-alpha was also observed in response to malarial antigen stimulation. These data suggest that elevated production of IFN-gamma, as part of a carefully regulated cytokine network, is important in the control of PM.
    The Journal of Infectious Diseases 06/1999; 179(5):1218-25. · 5.85 Impact Factor

Publication Stats

1k Citations
118.49 Total Impact Points

Institutions

  • 2000–2004
    • Kenya Medical Research Institute
      • Centre for Global Health Research
      Nairoba, Nairobi Area, Kenya
    • University of Georgia
      • Center for Tropical and Emerging Global Diseases
      Athens, GA, United States
  • 1997–1999
    • Centers for Disease Control and Prevention
      • • Division of Parasitic Diseases and Malaria
      • • National Center for Emerging and Zoonotic Infectious Diseases
      Atlanta, MI, United States