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Biomedical subjects

R W Ryder

Publications and source records attributed to R W Ryder.

At least 37 records · Page 2Linked to original sources
PubMed1993

Impact of HIV counseling and testing among child-bearing women in Kinshasa, Zaïre.

OBJECTIVE: To determine the impact of HIV counseling and testing among child-bearing women. STUDY SETTING: Mama Yemo Hospital in Kinshasa, Zaïre. PARTICIPANTS AND INTERVENTIONS: After informed consent, 187 HIV-seropositive and 177 HIV-seronegative child-bearing women received pre- and post-test counseling for HIV infection. MAIN OUTCOME MEASURES: Participant knowledge of HIV/AIDS and plans for notifying partners of serologic status and contraceptive use at the time of counseling, and actual partner involvement and contraception use 12 months later. RESULTS: During pre-test counseling, participant knowledge of HIV infection was high, although 30% of women were unaware of perinatal HIV transmission, and 50% did not know that HIV infection could be asymptomatic. At post-test counseling, 70% of mothers (47% of HIV-seropositive, 94% of HIV-seronegative) intended to notify their partners and have joint counseling and testing, although after 12 months, only 2.2% of all women and 7.9% of those who desired assistance to notify their partner returned with their partners for joint counseling and testing. Similarly, 86% planned to use birth control (61% condoms), with HIV-seropositive women more likely to prefer condoms than HIV-seronegative women (71 versus 53%; P < 0.001). After 12-months, however, only 20% of HIV-seropositive women reported condom use, and the frequency of pregnancy in both groups was approximately equal. CONCLUSIONS: HIV counseling and testing led to higher rates of contraceptive and condom use, although the actual level was lower than the intended use. To further reduce the risk of heterosexual and perinatal HIV transmission in families with an HIV-infected woman, counseling should also include their male partners.

Adult↗
PubMed1992

Persistent hepatitis B virus infection and hepatoma in The Gambia, west Africa. A case-control study of 140 adults and their 603 family contacts.

To determine the incidence of persistent hepatitis B virus infection and its etiologic role as a cause of hepatoma, the authors carried out a case-control investigation of 70 persons with hepatoma, 70 controls, and their families in 1981-1982 in The Gambia, West Africa. The risk of developing hepatoma after the age of 39 years was 1.4% in men and 0.3% in women. Hepatoma occurred more than twice as frequently among persons who had four or more older siblings as among persons who had less than two older siblings. The attributable risk between persistent infection with hepatitis B virus and hepatoma was 78% for individuals aged less than 50 years and 37% for persons aged 50 years or more, with an overall risk of 53%. The high prevalence of hepatitis B surface antigen and hepatitis B e antigen antigenemia in children under 15 years of age (14% of 341 children) and the positive correlation between late birth order and risk of developing hepatoma suggest that postnatal early childhood exposure to hepatitis B virus is an important risk factor. The use of a hepatitis B virus vaccine which provides durable immunity in very young children will probably prevent most cases of hepatoma.

Adolescent↗
PubMed1992

Genital papillomavirus infection and cervical dysplasia--opportunistic complications of HIV infection.

Certain human genital papillomaviruses (HPV) are strongly associated with cervical dysplasia and cancer. Evidence is accumulating that HPV infection and ano-genital cancers are more common in patients with the acquired immunodeficiency syndrome. The objective of our study was to evaluate the extent to which HPV infection and associated cervical disease constitute opportunistic complications of human immunodeficiency virus (HIV) infection in a population of sexually promiscuous, HIV-infected women in Kinshasa, Zaire. In 1989 we obtained Pap smears and cervicovaginal lavage specimens for HPV DNA testing from 47 HIV-seropositive and 48 HIV-seronegative prostitutes who were part of a cohort under observation since 1988. Thirty-eight percent of the HIV-seropositive and 8% of the seronegative women (odds ratio = 6.8; p = 0.001) had HPV DNA detected by either ViraType, a dot-blot assay which detects specific genital HPV types, or low-stringency Southern blot, which detects all HPV types. Eighty-two women (86%) had an interpretable Pap smear; 11 of 41 (27%) HIV-seropositive women and one of 41 (3%) seronegative women had cervical intra-epithelial neoplasia (CIN) (odds ratio = 14.7; p = 0.002). HIV seropositivity, HPV infection and CIN were highly associated. Eight (73%) of 11 seropositive women with CIN had HPV detected. Both HPV infection and cervical cancer may emerge as opportunistic complications of HIV infection in populations in which HIV, HPV and cervical cancer are common.

DNA, Viral↗
PubMed1992

Diarrhea among African children born to human immunodeficiency virus 1-infected mothers: clinical, microbiologic and epidemiologic features.

Diarrhea and weight loss are common features of pediatric and adult human immunodeficiency type 1 (HIV-1) infection, particularly in developing countries. We studied prospectively episodes of diarrhea in 559 children, ages 10 to 15 months, participating in a longitudinal study of perinatal HIV-1 infection in Kinshasa, Zaire. Children with HIV-1 infection had more frequent episodes of diarrhea and were more likely to present with fever or moderate or severe dehydration and to have persistent or fatal diarrhea. Of 9 HIV-1-positive infants with diarrhea, 3 had enteroadherence factor-positive Escherichia coli, compared with 5 of 74 HIV-1-negative children with diarrhea (P = 0.04); no other pathogen was associated with HIV-1 infection. In a logistic regression model diarrhea was significantly associated with HIV-1 infection in the child, moderate or severe malnutrition and symptoms of acquired immunodeficiency syndrome in the mother. Diarrhea among children with perinatal HIV infection in Zaire is more severe than among uninfected children and is associated with malnutrition and advanced disease in the mother.

Cohort Studies↗
PubMed1992

Stability of human immunodeficiency virus type 1 antibodies in whole blood dried on filter paper and stored under various tropical conditions in Kinshasa, Zaire.

The use of whole-blood spots on filter paper for the detection of antibody to human immunodeficiency virus type 1 (HIV-1) was evaluated during a 20-week period under a variety of storage environments simulating the harsh tropical field conditions in Kinshasa, Zaire. During the first 6 weeks of storage, all replicates of high- and low-titer HIV-1-positive reference samples remained positive by enzyme immunoassay and Western blotting (immunoblotting), and all replicates of HIV-1-negative samples remained negative under all storage conditions. However, hot and humid storage conditions for up to 20 weeks caused a progressive decline in enzyme immunoassay optical density ratio values, which was particularly noticeable in samples with a low HIV-1 antibody titer. Harsh tropical operational conditions did not cause any repeatedly false-positive results during the 20-week storage period. The use of gas-impermeable bags with desiccant for the storage of blood spots on filter paper improved the stability of HIV-1 antibody detection over time and is recommended for the storage of whole-blood spots on filter paper in harsh tropical field settings.

Democratic Republic of the Congo↗
PubMed1992

Hepatitis B virus vaccine in The Gambia, West Africa: synergy between public health research and practice.

Hepatitis B virus infection is endemic in West Africa, and as a result, this region has a high rate of hepatoma. The recent development of an effective, safe vaccine against hepatitis B virus that provides durable immunity may now make feasible the prevention of persistent hepatitis B virus infection and thus the prevention of hepatoma. A comprehensive primary health care program in which over 70% of children in The Gambia, West Africa, receive all their childhood immunizations afforded a unique opportunity to carry out a large public health research program to prevent hepatoma and at the same time strengthen the country's primary health care program. In 1986, phased introduction of hepatitis B virus vaccine was initiated in The Gambia's Expanded Programme on Immunization. By 1990, 124,577 children had been carefully identified and recruited into the 35-year longitudinal cohort study; 59,803 of these children received hepatitis B virus vaccine. The other 62,774 unvaccinated children will serve as controls. Preliminary studies have demonstrated that the rate of hepatitis B virus infection has fallen to less than 5% in children who received all four doses of hepatitis B virus vaccine. This study should provide the data from which the protective efficacy of hepatitis B virus vaccine against hepatoma can be accurately determined. In addition, it has energized The Gambia's Expanded Programme on Immunization so that at present more than 90% of all children are receiving all their childhood immunizations. This model cancer prevention program demonstrates the potential synergy between public health research and practice.

Carcinoma, Hepatocellular↗
PubMed1992

Diagnosis of HIV infection with instrument-free assays as an alternative to the ELISA and western blot testing strategy: an evaluation in Central Africa.

The efficiency of an alternative instrument-free testing strategy was evaluated using a membrane-based rapid screening assay (HIVCHEK and its new version HIVCHEK1 + 2) in serial combination with a particle agglutination assay (SERODIA-HIV). Among 1,054 Zairian individuals at high risk of HIV infection, 573 were Western blot-positive for HIV-1 (54.4%) and none were Western blot-positive for HIV-2. In this group, the sensitivities of the serial combination HIVCHEK plus SERODIA-HIV and HIVCHEK1 + 2 plus SERODIA-HIV were 98.1 and 98.2%, respectively, and the specificities were 99.6 and 99.5% compared with HIV-1 Western blot. The positive predictive values were 99.6% for HIVCHEK plus SERODIA-HIV and 99.5% for HIVCHEK1 + 2 plus SERODIA-HIV; the negative predictive values were 97.8 and 97.9%, respectively. Among 1,495 pregnant women, 90 were Western blot-positive for HIV-1 (6.0%), and 54 of 1,510 blood donors were HIV-1 Western blot-positive (3.6%). None were positive for HIV-2. The sensitivities of HIVCHEK plus SERODIA-HIV and HIVCHEK1 + 2 plus SERODIA-HIV in these groups were 98.6 and 99.3%, respectively, and the specificities were 99.8 and 99.7%. The positive and negative predictive values of HIVCHEK plus SERODIA-HIV were 96.6 and 99.9%, respectively, and they were 94.1 and 99.9%, respectively, for HIVCHEK1 + 2 plus SERODIA-HIV. These instrument-free testing strategies are efficient alternatives for serodiagnosis of HIV-1 infection, although their cost should be further reduced.

AIDS Serodiagnosis↗
PubMed1991

Plasmodium Falciparum malaria and perinatally acquired human immunodeficiency virus type 1 infection in Kinshasa, Zaire. A prospective, longitudinal cohort study of 587 children.

BACKGROUND: It is uncertain whether Plasmodium falciparum malaria is more frequent or more severe in children with perinatally acquired human immunodeficiency virus type 1 (HIV-1) infection and whether P. falciparum infection accelerates the progression of HIV-related disease. METHODS: We conducted a prospective, longitudinal cohort study in Kinshasa, Zaire. Two hundred sixty children 5 to 9 months of age who had been born to HIV-1-seropositive mothers and 327 children of the same age who had been born to seronegative mothers were monitored intensively for malaria over a 13-month period. All episodes of fever were evaluated with blood smears for malaria, and children found to be infected with P. falciparum were treated with a standard regimen of oral quinine. RESULTS: A total of 2899 fevers were evaluated, with 271 cases of malaria identified. No statistically significant differences were found in the incidence, severity, or response to therapy of malaria among four well-defined groups of children: those with the acquired immunodeficiency syndrome (AIDS), those who were HIV-1-seropositive throughout the study, those who were born to HIV-1-seropositive mothers but reverted to seronegative, and those who were seronegative throughout the study. During the 13-month period the incidence of malaria in the 36 children with HIV infection in whom AIDS developed was lower, although not significantly so, than in the 37 in whom AIDS did not. CONCLUSIONS: In this study malaria was not more frequent or more severe in children with progressive HIV-1 infection and malaria did not appear to accelerate the rate of progression of HIV-1 disease.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Evidence of marked sexual behavior change associated with low HIV-1 seroconversion in 149 married couples with discordant HIV-1 serostatus: experience at an HIV counselling center in Zaire.

To determine the effect of an HIV-1 counselling program on 149 married Zairian couples with discordant HIV-1 serology, the rates of HIV-1 seroconversion and reported condom utilization have been observed during 382.4 person-years of follow-up (minimum follow-up time per couple of 6 months). Before determination of HIV-1 serostatus and counselling, less than 5% of these couples had ever used a condom. One month after notification of HIV-1 serostatus and counselling, 70.7% of couples reported using condoms during all episodes of sexual intercourse. At 18 months follow-up, 77.4% of the 140 couples still being followed reported continued use of condoms during all episodes of sexual intercourse. At the time of notification of HIV-1 serostatus, 18 couples experienced acute psychological distress. Home-based counselling by trained nurses resolved these difficulties in all but three couples who subsequently divorced. Intensive counselling following notification of HIV-1 serostatus led to low rates of HIV-1 seroconversion (3.1% per 100 person-years of observation) in Zairian married couples with discordant HIV-1 serostatus who voluntarily attended an HIV counselling center.

Adult↗
PubMed1991

Evidence from Zaire that breast-feeding by HIV-1-seropositive mothers is not a major route for perinatal HIV-1 transmission but does decrease morbidity.

Breast-feeding as a route of HIV-1 transmission during infancy but also as a protective measure against early childhood morbidity has been investigated prospectively in children born to HIV-1-seropositive mothers and control children born to age- and parity-matched HIV-1-seronegative women. The mothers of all study children had been enrolled antenatally at a maternity hospital in Kinshasa, Zaire, which served a relatively affluent group of women who sometimes chose not to breast-feed their infants. In 106 children born to HIV-1-seropositive women, the rate of HIV-1 transmission was 21% in 28 infants exclusively breast-fed, 19% in 68 infants both breast- and bottle-fed and 0% in 10 infants who were bottle-fed only (P = 0.35). In contrast, non-HIV-1-infected children of both HIV-1-seropositive and HIV-1-seronegative mothers who were exclusively breast-fed compared with uninfected children who were not exclusively breast-fed had significantly lower incidence rates of acute diarrhea, fever and lower respiratory tract infection. The lack of a dose-response effect between breast-feeding and perinatal HIV-1 transmission and the presence of a protective effect of breast-feeding against common causes of early childhood morbidity and mortality support the current World Health Organization recommendation that breast-feeding should continue to be promoted in all developing countries, including those with high HIV-1 prevalence rates in women of childbearing age.

Breast Feeding↗
PubMed1991

Fertility rates in 238 HIV-1-seropositive women in Zaire followed for 3 years post-partum.

Birth-control use and fertility rates were prospectively determined in 238 HIV-1-seropositive and 315 HIV-1-seronegative women in Kinshasa, Zaire, during the 36-month period following the delivery of their last live-born child. No women delivered children during the first follow-up year. Birth-control utilization rates (percentage use during total observation time) and fertility rates (annual number of live births per 1000 women of child-bearing age) in the second year of follow-up were 19% (107.4 per 1000) for HIV-1-seropositive women and 16% (144.7 per 1000) for HIV-1-seronegative women. In the third year of follow-up these rates were 26 (271.0 per 1000) and 16% (38.6 per 1000) for HIV-1-seropositive and HIV-1-seronegative women, respectively (P less than 0.05 for the difference in birth-control utilization and fertility rates between seropositive and seronegative women in the third year of follow-up). Seven (2.9%) of the 238 HIV-1-seropositive women initially included in the study brought their sex partners in for HIV-1 testing; three (43%) of these men were found to be HIV-1-seropositive. New HIV-1 infection did not have a dramatic effect on the fertility of seropositive women. The nearly uniform unwillingness of HIV-1-seropositive women to inform husbands or sexual partners of their HIV-1 serostatus accounted in large part for the disappointingly high fertility rates in seropositive women who had been provided with a comprehensive program of HIV counseling and birth control. Counseling services for seropositive women of child-bearing age which do not also include these women's sexual partners are unlikely to have an important impact on their high fertility rates.

AIDS-Related Complex↗
PubMed1991

Comparison of five commercial enzyme-linked immunosorbent assays and Western immunoblotting for human immunodeficiency virus antibody detection in serum samples from Central Africa.

Detection by five different enzyme-linked immunosorbent assays (ELISAs) of antibody to human immunodeficiency virus (HIV) in sera from three Zairian populations consisting of 1,998 individuals with various risks for HIV infection was evaluated. Sera that were reactive by at least one assay and 10% of the nonreactive serum samples were analyzed by Western blot (immunoblot) by using U.S. Public Health Service interpretation criteria. Sera which were positive by ELISA for detection of antibody to HIV-1 and HIV-2 and negative or indeterminate by HIV-1 Western blot were also analyzed by HIV-2 Western blot. Overall, 443 (22.2%) serum specimens were HIV-1 Western blot positive, 390 (19.5%) had indeterminate HIV-1 Western blot patterns, and no samples were HIV-2 Western blot positive. The sensitivity of the ELISAs ranged from 97.5 to 99.8%, and the specificity ranged from 51.7 to 98.4%. By population group, the negative predictive value ranged from 97.1 to 100%, in contrast to the positive predictive value, which varied from 6.6 to 100%. Follow-up results for sera which were indeterminate for antibody to HIV-1 documented only four seroconversions (6.0%) among 67 individuals at high risk for HIV-1 infection and no seroconversions among 202 individuals at relatively low risk for HIV-1 infection. This study demonstrates the importance of evaluating commercial ELISAs with sera from appropriate geographical regions in order to select the most cost-effective and practical assay for use in that region. Furthermore, the high frequency of indeterminate Western blots for African sera emphasizes the continual need for improved confirmatory assays and interpretation criteria.

Blotting, Western↗
PubMed1991

A retrospective cohort study of the risk of tuberculosis among women of childbearing age with HIV infection in Zaire.

To determine the risk of active tuberculosis associated with HIV infection, we retrospectively studied a cohort of HIV-seropositive and HIV-seronegative women participating in an HIV perinatal transmission study in Kinshasa, Zaire. After a median follow-up of 32 months, new cases of proven pulmonary or clinically diagnosed tuberculosis occurred in 19 of the 249 HIV-seropositive women (7.6%, 3.1 cases per 100 person-years) compared with 1 of the 310 HIV-seronegative women (0.3%, 0.12 cases per 100 person-years), for a relative risk of 26 (95% confidence interval, 5 to 125). Proven pulmonary tuberculosis was diagnosed in 7 HIV-seropositive women (2.8%, 1.2 cases per 100 person-years) and 1 HIV-seronegative woman (0.3%, 0.12 cases per 100 person-years), for a relative risk of 10 (95% confidence interval, 1.5 to 47). We estimated that 66 cases of proven pulmonary tuberculosis in 100,000 person-years of follow-up in women of childbearing age could be attributed to HIV; this is 35% of their estimated total incidence of proven pulmonary tuberculosis. Among those followed for 2 yr, 27 (11%) of 243 HIV-seropositive women died during 2 yr of follow-up compared with none of 296 HIV-seronegative women (p less than 0.001). In HIV-seropositive women with proven or clinically diagnosed tuberculosis mortality was even higher: 5 (26%) of the 19 HIV-seropositive women with proven pulmonary or clinically diagnosed tuberculosis died during follow-up compared with 22 (10%) of the 224 HIV-seropositive women not diagnosed as having tuberculosis (relative risk 2.7; 95% confidence interval, 1.1 to 6.3).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Increased mortality and tuberculosis treatment failure rate among human immunodeficiency virus (HIV) seropositive compared with HIV seronegative patients with pulmonary tuberculosis treated with "standard" chemotherapy in Kinshasa, Zaire.

To evaluate their treatment outcomes 170 human immunodeficiency virus (HIV) seropositive and 597 HIV seronegative patients with active pulmonary tuberculosis (TB) treated for 1 yr with "standard" chemotherapy, including streptomycin, isoniazid, and, in most cases, thiacetazone, were traced at completion of therapy. All 582 survivors were invited for reevaluation, and 385 patients, of whom 82 (21.3%) were HIV seropositive, were evaluated. Of those, 325 consenting patients, of whom 67 (20.6%) were HIV seropositive, were followed for 12 months. One year after TB had been diagnosed 47 (31.3%) of the 150 HIV seropositive and 22 (4.4%) of the 501 HIV seronegative patients traced had died (p = 10(-6]. During the subsequent year the mortality of 67 HIV seropositive patients (26.3/100 patient-years) was higher than that of the 303 HIV seronegative patients (2.2/100 patients-years, p = 10(-6]. HIV seropositive patients had a higher overall TB therapy failure rate 24 months after the diagnosis of TB than did HIV seronegative patients (21.1/100 patient-years versus 8.1/100 patient-years, p = 0.002), mainly because their relapse rate of pulmonary TB (18.1/100 patient-years) was higher than that of HIV seronegative patients (6.0/100 patient-years, p = 0.03). Given their higher relapse rate after 1 yr of "standard" chemotherapy, the public health impact of routine maintenance therapy in HIV seropositive patients with pulmonary TB who complete such therapy should be assessed in comparison to the introduction of rifampicin-based short-course antituberculosis chemotherapy in developing countries.

Antitubercular Agents↗
PubMed1991

Detection of salivary HIV-1-specific IgG antibodies in high-risk populations in Zaire.

Saliva and blood samples were tested for human immunodeficiency virus-1 (HIV-1) antibodies in two high-risk populations in Kinshasa, Zaire. In a seroprevalence study of 458 sexually transmitted disease (STD) clinic attendees, 142 of 145 seropositive individuals had enzyme-linked immunosorbent assay (ELISA)-positive saliva samples (97.9% sensitivity). All saliva samples from seronegative patients were ELISA-negative (100% specificity). Of the 142 ELISA-positive saliva specimens, 137 were also Western blot-positive (94.5% sensitivity). In a subsequent seroincidence study of 315 initially seronegative female prostitutes followed during 183 woman-years of observation, 9 of 14 women who seroconverted (7.7% seroincidence) had ELISA-positive saliva samples at the time seroconversion was detected. Only three of these saliva specimens could be confirmed by Western blot. Although salivary testing for HIV-1 antibodies using conventional assays was not sensitive in detecting recent seroconversions, screening of salivary samples for HIV-1 antibody provides a convenient alternative method for conducting seroprevalence surveys in populations in whom venipuncture is not possible or convenient.

Adult↗
PubMed1990

Prevention of transfusion-associated HIV transmission in Kinshasa, Zaire: HIV screening is not enough.

The purpose of this study was to develop a strategy to reduce transfusion-related HIV transmission which went beyond the limits of routine HIV screening of blood donors. Current blood transfusion practices were assessed in 1044 patients for whom staff physicians had requested a transfusion between 5 September and 19 October, 1988. Children under 5 years of age with malaria, and pregnant women with acute anaemia requiring blood transfusion were the two highest risk groups. Many of the transfusions were given without an obvious medical indication; 22.7% (214 out of 955) of the recipients were transfused without prior laboratory tests [haemoglobin (Hb) or haematocrit (Hct)], 7.2% with Hb greater than 6g/100ml or Hct greater than 25% and 16.6% without clinical signs of severe anaemia (pulse less than 100/min without shortness of breath). The data of this study were used to organize a workshop for all the physicians responsible for blood transfusions in Kinshasa and two nearby health zones. A consensus statement on the indications for blood transfusion was developed. Subsequently, transfusion centres adopted this consensus statement instead of previous guidelines.

Adolescent↗