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R W Ryder

Publications and source records attributed to R W Ryder.

At least 19 recordsLinked to original sources
PubMed2000

The emergence of another tickborne infection in the 12-town area around Lyme, Connecticut: human granulocytic ehrlichiosis.

Human granulocytic ehrlichiosis (HGE) is an emerging tickborne infection, increasingly recognized in areas in which Lyme disease is endemic, but there are few data on the incidence of HGE. Prospective population-based surveillance was conducted in the 12-town area around Lyme, Connecticut, by means of both active and passive methods, from April through November of 1997, 1998, and 1999. Five hundred thirty-seven residents presenting to their primary care provider with an acute febrile illness suggestive of HGE were identified. Of these, 137 (26%) had laboratory evidence (by indirect fluorescent antibody staining or polymerase chain reaction) of HGE; 89 were confirmed cases, and 48 were probable cases. The incidence of confirmed HGE was 31 cases/100,000 in 1997, 51 cases/100,000 in 1998, and 24 cases/100,000 in 1999. A subset of sera was tested by use of immunoblot assays, and results were in agreement with indirect fluorescent antibody methods for 86% of samples analyzed. Thus, HGE is an important cause of morbidity and is now the second most common tickborne infection in southeastern Connecticut.

Adolescent↗
PubMed1999

Use of state hospital discharge data to assess the morbidity from rotavirus diarrhea and to monitor the impact of a rotavirus immunization program: A pilot study in Connecticut.

OBJECTIVES: Now that rotavirus vaccines have been licensed and recommended for routine immunization of US infants, there is an urgent need for data to assess the morbidity from rotavirus diarrhea and to monitor the impact of a rotavirus immunization program. In a pilot study, we have assessed the usefulness of state hospital discharge data on diarrhea in children to provide this information by examining data from Connecticut. DESIGN: Retrospective analysis of discharge records from acute care, nongovernmental hospitals in Connecticut. Patients. Children 1 month through 4 years of age with a diarrhea-associated diagnosis listed on the discharge record. Setting. Connecticut, 1987 through 1996. RESULTS: During the 10-year study period, a total of 11 324 diarrhea-associated hospitalizations (49.4 hospitalizations per 10,000 children) were reported. Diarrhea-associated hospitalizations peaked during February through April, especially among children 4 to 35 months of age. The seasonality and age distribution of diarrhea-associated hospitalizations of presumed noninfectious and viral etiologies resembled those of rotavirus-associated hospitalizations. During 1993 to 1996, rotavirus was coded for 10.4% of diarrhea-associated hospitalizations increasing from 8.6% in 1993 to 14.7% in 1996. The unadjusted median cost of a diarrhea-associated hospitalization during 1987 to 1996 and 1993 to 1996 was $1,941 and $2,428, respectively. CONCLUSIONS: Diarrhea causes substantial morbidity in children from Connecticut. The winter seasonal peak of diarrhea-associated hospitalizations in children 4 to 35 months of age coinciding with the peak of rotavirus-specific hospitalizations suggests that rotavirus is an important contributor to the overall morbidity. Although our findings suggest incomplete coding of rotavirus cases, state hospital discharge data should provide sensitive and timely information to monitor the impact of a rotavirus immunization program in Connecticut.

Child, Preschool↗
PubMed1994

A longitudinal study of human papillomavirus DNA detection in human immunodeficiency virus type 1-seropositive and -seronegative women.

Cericovaginal lavage samples from 124 human immunodeficiency virus type 1 (HIV-1)-seropositive and 126 HIV-1-seronegative women were collected monthly for 8 months and tested for human papillomavirus (HPV) DNA. The estimated prevalence of HPV was 42.8% in HIV-1-seropositive and 13.4% in -seronegative women (P < .001). There was no significant difference in HPV DNA detection in HIV-1-seropositive women with CD4 cell counts of < 300/mm3 (50% HPV-positive), 300-499/mm3 (36.4% HPV-positive), or > or = to 500/mm3 (40.5% HIV-positive). However, HIV-1-seropositive women who were more immunocompromised, as indicated by lower CD4 cell counts, were more likely to shed HPV persistently. The quantity of HPV DNA detected in cervicovaginal lavage samples was similar in HIV-1-seropositive and -seronegative women. This study further defined the characteristics of HPV infections in HIV-1-infected women.

Cervix Uteri↗
PubMed1994

Mortality in HIV-1-seropositive women, their spouses and their newly born children during 36 months of follow-up in Kinshasa, Zaïre.

OBJECTIVE: To calculate 3-year mortality rates in HIV-1-seropositive and HIV-1-seronegative mothers, their newborn children and the fathers of these children. DESIGN: Longitudinal cohort study of HIV-1-seropositive, age and parity-matched HIV-1-seronegative pregnant women, their newborn babies and the fathers of these children. SETTING: Obstetric ward and follow-up clinic at a large municipal hospital in Kinshasa, Zaïre. PARTICIPANTS: A total of 335 newborn children and their 327 HIV-1-seropositive mothers and 341 newborn children and their 337 HIV-1-seronegative mothers and the fathers of these children. MAIN OUTCOME MEASURES: Rates of vertical HIV-1 transmission and maternal, paternal and early childhood mortality. RESULTS: The lower and upper bounds of vertical transmission were 27 and 50%, respectively. The 3-year mortality rate was 44% in children with vertically acquired HIV-1 infection, 25% in children with HIV-1-seropositive mothers and indeterminant HIV-1 infection status, and 6% in uninfected children with HIV-1-seronegative mothers. HIV-1-seropositive women who transmitted HIV-1 infection to their most recently born child had lost a greater number of previously born children (mean, 1.5 versus 0.5; P < 0.05), were more likely to have had AIDS at delivery (25 versus 12%; P < 0.01) and were more likely to die during follow-up (22 versus 9%; P < 0.01) than HIV-1-seropositive women who did not transmit HIV-1 infection to their newborn child. Twenty-five out of 239 (10.4%) fathers of children with HIV-1-seropositive mothers, not lost to follow-up, died compared with three out of 310 (1%) fathers of children with HIV-1-seronegative mothers (P < 0.01). CONCLUSIONS: Families in Kinshasa, Zaïre, in which the mother was HIV-1-seropositive experienced a five to 10-fold higher maternal, paternal and early childhood mortality rate than families in which the mother was HIV-1-seronegative.

Acquired Immunodeficiency Syndrome↗
PubMed1994

AIDS orphans in Kinshasa, Zaïre: incidence and socioeconomic consequences.

OBJECTIVE: To determine the incidence, morbidity, mortality, and socioeconomic consequences of becoming an AIDS orphan (a child with an HIV-1-seropositive mother who has died) in Kinshasa, Zaïre. DESIGN: A longitudinal cohort study was undertaken between 1986 and 1990. Within this cohort, a nested case-control study of AIDS orphans was performed. AIDS orphan cases were children with an HIV-1-seropositive mother who had died. Two groups of control children were identified. The first group of control children were age-matched children with HIV-1-seropositive mothers who were alive at the time of death of the AIDS orphan case mother. The second group of control children were children with HIV-1-seronegative mothers who were also alive at the time of death of the AIDS orphan case mother. SETTING: Obstetric ward and follow-up clinic at two large municipal hospitals in Kinshasa, Zaïre. PARTICIPANTS: A total of 466 HIV-1-seropositive women, their children, and the fathers of these children; 606 HIV-1-seronegative women, their children, and the fathers of these children. MAIN OUTCOME MEASURES: AIDS orphan incidence, HIV-1 vertical transmission rate, morbidity, mortality and socioeconomic indicators of the consequences of becoming an AIDS orphan. RESULTS: The AIDS orphan incidence rate was 8.2 per 100 HIV-1-seropositive women-years of follow-up. Vertical transmission of HIV-1 was higher in AIDS orphan cases (41%) than in control children with HIV-1-seropositive mothers (26%; P < 0.05). Among children without vertically acquired HIV-1 infection, morbidity rates and indices of social and economic well-being were similar in AIDS orphans and control children. Five out of 26 (19%) AIDS orphan cases died during follow-up, compared with three out of 52 (6%) control children (P < 0.05). CONCLUSION: During a 3-year follow-up period, children with HIV-1-seropositive mothers had a considerable risk of becoming an AIDS orphan. However, the presence of a concerned extended family appeared to minimize any adverse health and socioeconomic effects experienced by orphan children.

Acquired Immunodeficiency Syndrome↗
PubMed1994

High HIV-1 incidence in young women masked by stable overall seroprevalence among childbearing women in Kinshasa, Zaïre: estimating incidence from serial seroprevalence data.

OBJECTIVE: To describe the dynamics of the HIV-1 epidemic in childbearing women in Kinshasa, Zaïre, by estimating incidence from serial seroprevalence studies. METHODS: In 1986 and 1989, 5937 and 4623 pregnant women, respectively, were screened for HIV-1 in Kinshasa. We estimated age-specific incidence from two seroprevalence surveys by using a birth-year cohort analysis and adjusting for differences in mortality and fertility between HIV-1-infected and uninfected women. Mortality and fertility data were measured in a cohort of women recruited from the survey in 1986 and followed until 1989. RESULTS: While the overall HIV-1 seroprevalence changed little (5.8% in 1986 and 6.5% in 1989; P = 0.17), the prevalence increased in birth-year cohorts of women under 25 years of age in 1989 from 3.2 to 6.2% (P < 0.001), but decreased for women above 25 years of age from 6.9 to 6.7% (P = 0.7). In addition, new HIV infections between 1986 and 1989 were balanced by a higher mortality and lower fertility observed in HIV-infected women. After adjusting for these effects, we estimated an overall 3-year cumulative HIV-1 incidence of 2.8 per 100 uninfected women [95% confidence interval (CI), 1.4-4.2]. The highest incidence, 5.7 per 100 (95% CI, 3.5-8.0), was in women aged 20-24 years in 1989. CONCLUSION: Despite an overall relatively stable HIV-1 prevalence in childbearing women in Kinshasa between 1986 and 1989, approximately 40% of all HIV-1 infections detected in the 1989 survey occurred between 1986 and 1989, and 60% occurred in women under 25 years of age in 1989.

Adult↗
PubMed1993

Spectrum of immunodeficiency in HIV-1-infected patients with pulmonary tuberculosis in Zaire.

Tuberculosis (TB) is the most common opportunistic infection in African patients who die from AIDS, yet the stage of immunodeficiency at which TB develops is uncertain. We studied the immune status of HIV-infected outpatients with pulmonary TB in relation to their clinical presentation in a cross-sectional study of 216 HIV-seropositive and 146 HIV-seronegative ambulatory incident cases of smear-positive and culture-positive pulmonary TB in Kinshasa, Zaire. HIV-seropositive and seronegative patients had median CD4 lymphocyte counts of 316.5/microL and 830.5/microL, respectively. Of the HIV-seropositive patients, 32.9% had less than 200 CD4 lymphocytes/microL, 37% between 200 and 499, and 30.1% 500 or more. Clinical AIDS, as defined by the WHO clinical case-definition or a modified version, was of similar limited use as a predictor of immunodeficiency. Among HIV-seropositive patients, oral candidosis, lymphopenia, a negative tuberculin purified protein derivative test, and cutaneous anergy were strongly associated with CD4 counts of less than 200/microL, and seemed to be better markers of immune dysfunction. We conclude that pulmonary TB develops across a broad spectrum of HIV-induced immunodeficiency and that a diagnosis of pulmonary TB is of limited use as a marker of stage of HIV disease in African HIV-infected outpatients.

AIDS-Related Opportunistic Infections↗
PubMed1993

Risk for perinatal HIV-1 transmission according to maternal immunologic, virologic, and placental factors.

OBJECTIVE: To evaluate how maternal and obstetric factors interact to influence mother-to-child human immunodeficiency virus type 1 (HIV-1) transmission. DESIGN: Prospective, observational cohort study of children born to HIV-infected women to determine child's HIV infection status. The analysis then compared peripartum maternal, placental, and obstetric variables between HIV-1 transmitter and nontransmitter women. SETTING: Two large maternity wards in Kinshasa, Zaire. PARTICIPANTS: Consecutive sample of 324 HIV-1-infected women at delivery, with 254 HIV-seronegative women followed up as control subjects. PRINCIPAL OUTCOME MEASURES: HIV infection status of children, to classify each woman as an HIV-1 transmitter or nontransmitter. RESULTS: The highest transmission risk (TR) was associated with maternal p24 antigenemia (TR, 71%; relative risk [RR], 3.0; 95% confidence interval [CI], 1.7 to 5.2) and maternal CD8+ lymphocyte counts of at least 1.80 x 10(9)/L (1800/microL) (TR, 50%; RR, 2.2; 95% CI, 1.2 to 4.2). Among women with CD8+ lymphocyte counts of less than 1.80 x 10(9)/L, CD4+ lymphocyte counts of less than 0.60 x 10(9)/L were a risk factor (TR, 29%; RR, 2.2; 95% CI, 1.2 to 4.2). In women with neither high CD8+ nor low CD4+ lymphocyte counts, placental membrane inflammation was associated with perinatal transmission (TR, 40%; RR, 4.2; 95% CI, 1.3 to 13.7). In women with neither p24 antigenemia, high CD8+ or low CD4+ lymphocyte counts, nor placental membrane inflammation, the transmission risk was only 7%. Additional correlates of transmission included maternal anemia and fever, but not maternal sexually transmitted diseases. CONCLUSIONS: Identifiable subgroups of HIV-1-infected women based on maternal and placental characteristics had between a 7% and 71% risk of perinatal HIV-1 transmission. Not only the overall rate of transmission but the impact of different risk factors for transmission appear to vary over the course of HIV infection.

AIDS Serodiagnosis↗
PubMed1993

Genital types of papillomavirus in children of women with HIV-1 infection in Kinshasa, Zaire.

Increasing evidence indicates that infection with genital types of human papillomavirus (HPV) can occur prior to the onset of sexual activity, possibly by perinatal transmission. Evidence is also accumulating that women infected with the human immunodeficiency virus (HIV) more frequently express HPV. We conducted this study to measure HPV prevalence in HIV-seropositive and -seronegative women in Kinshasa, Zaire and in their children. We collected cervico-vaginal lavage specimens from 80 mothers (52 HIV-seropositive and 28 HIV-seronegative at the time of delivery) and oropharyngeal and perineal specimens from their 81 3-year old children (21 HIV-seropositive and 60-seronegative). We used the ViraPap and ViraType assay to test specimens for HPV DNA by the dot-blot technique. Detection of HPV in the mother was highly associated with HIV: 20 HIV-seropositive women and one seronegative woman had HPV DNA. Ten children had HPV DNA. However, detection of HPV in the children was not associated with the mothers' HPV or HIV status or with the child's own HIV status. These findings document a substantial prevalence in young children of HPV DNA types that are linked to genital-tract neoplasia in adults, but do not specifically support a hypothesis of mother-to-child transmission of genital HPV types.

DNA, Viral↗
PubMed1993

Safety and immunogenicity of bacille Calmette-Guérin, diphtheria-tetanus-pertussis, and oral polio vaccines in newborn children in Zaire infected with human immunodeficiency virus type 1.

OBJECTIVE: To determine the safety and immunogenicity of childhood vaccines in children with perinatally acquired human immunodeficiency virus type 1 (HIV-1) infection. DESIGN: Nonrandomized, prospective cohort study; 12-month follow-up period. SETTING: Obstetric wards and outpatient pediatric clinics at two large hospitals in Kinshasa, Zaire. PATIENTS: A total of 8108 pregnant women were screened for HIV-1 antibodies. The 474 children born to 466 seropositive women identified during screening and the 616 children born to 606 seronegative, age- and parity-matched women were vaccinated. INTERVENTION: The following vaccines were administered at the stated ages: bacille Calmette-Guérin (BCG) vaccine (2 days); trivalent oral Sabin poliomyelitis vaccine (2 days and 6, 10, and 14 weeks); and adsorbed diphtheria-tetanus-pertussis (DTP) vaccine (6, 10, and 14 weeks). MEASUREMENTS AND MAIN RESULTS: Protective antibody titers to tetanus and poliovirus types 1, 2, and 3 were achieved in 95% of all children. Among children with HIV-1 infection, 70.8% had protective antibody titers to diphtheria compared with 98.5% of uninfected children (p < 0.05). Geometric mean antibody titers to diphtheria and poliovirus types 1, 2, and 3 were significantly lower in children with HIV-1 infection than in uninfected children. Vaccine-associated side effects were similarly low in all children. CONCLUSIONS: The low incidence of side effects and the high proportion of children with HIV-1 infection who achieved protective postimmunization antibody titers support the continuing use of BCG, DTP, and oral polio vaccines in childhood immunization programs in HIV-1 endemic areas.

Antibodies, Bacterial↗
PubMed1993

Mycobacterium tuberculosis in household contacts of human immunodeficiency virus type 1-seropositive patients with active pulmonary tuberculosis in Kinshasa, Zaire.

Rates of infection with Mycobacterium tuberculosis were compared in Kinshasa, Zaire, in 521 household contacts of 74 human immunodeficiency virus type 1 (HIV-1)-seropositive index patients and in 692 household contacts of 95 HIV-1-seronegative [corrected] index patients with sputum smear-positive pulmonary tuberculosis: No difference was noted between contacts of HIV-1-seropositive and -seronegative patients. The increasing prevalence of M. tuberculosis infection with increasing age was similar in household contacts of seropositive and seronegative patients; by age 16 years, 75% were purified protein derivative-positive. The similarly low rates of M. tuberculosis infection in household contacts of HIV-1-seropositive and -seronegative index patients with sputum smear-positive pulmonary tuberculosis indicates that HIV-1-seropositive patients with pulmonary tuberculosis are not more infectious than HIV-1-seronegative patients with pulmonary tuberculosis.

Adolescent↗
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↗