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Biomedical subjects

F A Plummer

Publications and source records attributed to F A Plummer.

At least 127 records · Page 7Linked to original sources

The prevalence of Chlamydia trachomatis infection among mothers of children with trachoma.

The authors studied the epidemiology of Chlamydia trachomatis infection in a trachoma-endemic area of central Kenya. Children with abnormal ocular discharge were evaluated for clinical evidence of trachoma and were cultured for C. trachomatis. Isolated strains of C. trachomatis were immunotyped with monoclonal antibodies. Overall, 221 children from 207 families were evaluated. Clinically, 91 children (41%) had trachomatous follicular inflammation, and 130 (59%) had papillary hypertrophy without visible follicle and were labeled as having mucopurulent conjunctivitis. C. trachomatis was isolated from 31 of 91 children with trachoma (34%) and 17 of 130 children with conjunctivitis (13%) (p less than 0.001). Twenty-two C. trachomatis strains were immunotyped: 17 were from children with trachoma (nine type A, one A/L2, five B, one Ba, and one E) and five were from children with conjunctivitis (two A, one Ba, one D, and one F). A total of 168 mothers were evaluated for cervical C. trachomatis infection, and seven (4%) were culture-positive. Two strains were immunotyped as serovar E. The authors conclude that C. trachomatis ocular infections are due to heterogeneous serovars in this area, that most cases of trachoma are due to C. trachomatis infection with the classic trachoma serovars (A, B, or Ba), and that cervical C. trachomatis infection is uncommon among mothers of children with trachoma.

Adolescent↗

HIV infection among lower socioeconomic strata prostitutes in Nairobi.

A cohort of 418 lower socioeconomic strata prostitutes were enrolled in a study of the epidemiology of sexually transmitted diseases (STDs) between January and April 1985. Sixty-two per cent of the women were seropositive for HIV infection at enrollment. Significant associations were found between HIV seropositivity and Tanzanian origin (OR = 2.12, CI 95% = 1.18-3.81, P less than 0.03), younger age, a shorter duration of prostitution, reduced fecundity, use of oral contraceptives (OR = 1.8, CI 95% = 1.1-2.9, P less than 0.05) and genital ulcer disease (OR = 3.32, P less than 0.00001). No associations were noted with other STD. Stepwise logistic regression analysis confirmed independent associations between HIV infection and Tanzanian origin (OR = 2.27, CI 95% = 1.25-4.14, P less than 0.007), reduced fecundity (OR = 0.83, CI 95% = 0.74-0.94, P less than 0.003), oral contraceptive use (OR = 2.02, CI 95% = 1.22-3.35, P less than 0.006) and duration of prostitution (OR = 0.39, CI 95% = 0.23-0.65, P less than 0.004). Oral contraceptives may increase susceptibility to HIV or may be a marker for other factors which increase risk of acquisition. Further studies are necessary to confirm this association.

Acquired Immunodeficiency Syndrome↗

Evaluation of a rapid membrane-based assay (HIV-CHEK) for detection of antibodies to HIV in serum samples from Nairobi.

We evaluated a rapid membrane-based assay (HIV-CHEK) for detection of antibodies to HIV using 737 serum samples in Nairobi, Kenya. The rapid assay had a sensitivity of 96.3% and specificity of 99.8% when compared with enzyme-linked immunosorbent assay (ELISA) and Western blot assay. Results were similar using fresh or previously frozen serum samples, although the latter occasionally left debris on the assay device membrane yielding uninterpretable results. This rapid HIV assay may be of particular use in developing countries where laboratory resources are limited.

Evaluation Studies as Topic↗

Transition dynamics of HIV disease in a cohort of African prostitutes: a Markov model approach.

The progression of HIV-related disease from infection to death is represented as a staged Markov model. Transitions between stages are considered reversible. The model is fitted to data from a cohort of African prostitutes by means of maximum likelihood. It appears that the progression to symptomatic disease (Centers for Disease Control stage IV) in this population is considerably more rapid than that reported from studies in Western countries.

Acquired Immunodeficiency Syndrome↗

Infection with HIV as a risk factor for adverse obstetrical outcome.

We carried out a case-control study to investigate the role of sexually transmitted diseases (STDs), including infection with HIV, as risk factors for adverse outcome of pregnancy. Overall, 1507 women were enrolled within 24 h of delivery. Cases (n = 796) were mothers of low-birthweight infants (less than 2500 g) or of stillborns. Low-birthweight infants were divided into preterms (n = 373) and neonates small for gestational age (n = 234). Stillborns were separated into intrauterine fetal deaths (n = 120), and intrapartum fetal deaths (n = 69). Controls were selected from mothers delivering a live baby of greater than or equal to 2500 g (n = 711). The maternal HIV seroprevalence in the control group was 3.1%. Prematurity was associated with maternal HIV antibody [8.6% seropositive; adjusted odds ratio (OR) 2.1; 95% confidence interval (CI) 1.1-4.0], as was being born small for gestational age (7.7% seropositive; adjusted OR 2.3; 95% CI 1.2-4.2). In mothers who delivered a stillborn baby, both intrauterine fetal death (11.7% seropositive; adjusted OR 2.7; 95% CI 1.3-5.5) and intrapartum fetal death (11.6% seropositive; adjusted OR 2.9; 95% CI 1.3-6.5) were independently associated with HIV seropositivity in the mother. Maternal syphilis was confirmed as an important risk factor for intrauterine fetal death (14.3% positive; adjusted OR 4.8; 95% CI 2.4-9.5). No significant association was found between other STDs, including gonococcal and chlamydial infection, and adverse obstetrical outcome. These results suggest an association between maternal HIV infection and adverse obstetrical outcome, defined as low birthweight and stillbirth.

Abortion, Spontaneous↗

Towards developing a diagnostic algorithm for Chlamydia trachomatis and Neisseria gonorrhoeae cervicitis in pregnancy.

C trachomatis and N gonorrhoeae are major causes of maternal and neonatal morbidity and mortality in developing countries. To identify characteristics predictive of cervical infection, we examined pregnant women attending an antenatal clinic in Nairobi, Kenya. C trachomatis was isolated from 14/178 (8%), and N gonorrhoeae from 17 (10%); cervical infection with either pathogen was present in 28 (16%). Two characteristics were independently predictive of cervical infection by logistic regression analysis; the presence of either endocervical mucopus or induced endocervical bleeding, relative risk 4.2 (95% confidence interval (CI) 2.2 to 8.0) and having more than one sexual partner during pregnancy, relative risk 3.3 (95% CI 1.4 to 7.6). A screening programme for cervical infection which tested women with one or both risk markers would have a sensitivity of 68% (95% CI 51 to 85%) and a positive predictive value of 0.35 (95% CI 0.22 to 0.47). In countries where resources are limited, diagnostic algorithms incorporating clinical signs and behavioural characteristics may be useful in identifying pregnant women at high risk of cervical infection.

Adult↗

Human immunodeficiency virus, genital ulcers and the male foreskin: synergism in HIV-1 transmission.

Epidemiologic studies in Nairobi and elsewhere in Africa, have shown that men infected with HIV-1 more commonly have a history of genital ulcer disease compared to uninfected men. In one study, HIV infected men were three times as likely to have a recent history of genital ulcers. In a prospective study of seronegative men, those presenting with chancroid had a five-fold risk of seroconversion during follow-up compared to men presenting with urethritis. Uncircumcised men had an increased risk of seroconversion which was independent of their risk of genital ulcer disease. Over 95% of attributable risk in men with STD was either genital ulceration or the presence of a foreskin. Genital ulcers are a major risk factor for HIV infection among prostitutes. The increased risk is about 10-fold among prostitutes with ulcers compared to a cohort who did not. We hypothesize from these studies that genital ulcers are the major portals of entry for HIV infection and also increased shedding of virus infected cells into the vaginal secretions. HIV seropositive prostitutes are more susceptible to chancroid with a two-fold increase in the prevalence of genital ulcers as compared to HIV negative women. The use of condoms by their clients prevents both genital ulcer disease and HIV acquisition among prostitutes. Chancroid is more difficult to treat in HIV infected men with one-third of patients failing single dose treatment regimens as compared to less than five percent of men without HIV infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Evaluation of fleroxacin (RO 23-6240) as single-oral-dose therapy of culture-proven chancroid in Nairobi, Kenya.

Chancroid is gaining importance as a sexually transmitted disease because of its association with transmission of human immunodeficiency virus type 1 (HIV-1). Effective, simply administered therapy for chancroid is necessary. Fleroxacin is effective against Haemophilus ducreyi in vitro. We performed an initial randomized clinical trial to assess the efficacy of fleroxacin for treatment of chancroid in Nairobi, Kenya. Fifty-three men with culture-positive chancroid were randomly assigned to receive either 200 mg (group 1) or 400 mg (group 2) of fleroxacin as a single oral dose. Groups 1 and 2 were similar with regard to severity of disease, bubo formation, and HIV-1 status. A satisfactory clinical response to therapy was noted in 23 of 26 patients (88%) in group 1 and 18 of 23 patients (78%) in group 2. Bacteriological failure occurred in 1 of 26 evaluable patients (4%) in group 1 and 4 of 23 evaluable patients (17%) in group 2. Two of 37 HIV-1-seronegative men (5%) and 3 of 11 HIV-1-infected men (27%) were bacteriological failures. Fleroxacin, 200 or 400 mg as a single oral dose, is efficacious therapy for microbiologically proven chancroid in patients who do not have concurrent HIV-1 infection. Among HIV-1-infected men, a single dose of 200 or 400 mg of fleroxacin is inadequate therapy for chancroid.

Acquired Immunodeficiency Syndrome↗

Epidemiologic evidence for the development of serovar-specific immunity after gonococcal infection.

We tested the hypothesis that strain-specific immunity occurs after gonococcal infection in a longitudinal study of 227 prostitutes resident in one small community who experienced frequent gonococcal infections. Women were examined and cultured for Neisseria gonorrhoeae at 2-wk intervals. Gonococcal isolates were typed according to protein 1 serovar, auxotype, and beta-lactamase plasmid type, and classified as to serovar and strain. The hypothesis was tested by comparing the predictions of the hypothesis with the observations of the study. Over the 14-mo period of the study, major changes in the prevalence of specific serovars were observed in the gonococcal population infecting these women. Women with HIV infection experienced a higher rate of gonococcal infection (0.56 +/- 0.03 vs. 0.46 +/- 0.04, P less than 0.05, t test) compared with HIV-negative women and were more likely to experience multiple infections with the same strain. The duration of prostitution was inversely related to the frequency of gonococcal infection. Women experiencing an infection with a specific gonococcal serovar were at a 2- to 10-fold reduced risk of reinfection with the same serovar, except for the 1B-1 serovar. The results of the study were consistent with all four predictions of the hypothesis. Infection with a specific gonococcal serovar results in specific but incomplete protection against subsequent infection with the homologous serovar. The mechanism of this protection remains to be determined.

Adult↗

Chancroid and granuloma inguinale.

Haemophilus ducreyi is a fastidious pathogen that can be routinely cultured with the appropriate media and incubation environment. Prostituted women appear to be the usual reservoir. In Africa, chancroid is emerging as the major risk factor for acquisition of HIV-1 following heterosexual intercourse. Despite the emergence of resistance to a number of antimicrobial agents, H. ducreyi remains susceptible to ceftriaxone, erythromycin, and ciprofloxacin. Control and eradication of outbreaks of chancroid have been successful on several occasions in Western societies; strategies to control epidemic genital ulcer disease are required in developing countries. Granuloma inguinale is caused by a small, gram-negative rod, which has never been well-characterized. The presence of Donovan bodies is a specific and sensitive diagnostic characteristic. Very little is known about the epidemiology of the disease. Specific treatment programs using trimethoprim-sulfamethoxazole or erythromycin seem to be quite effective. Control strategies have not been adequately investigated.

Campylobacter↗

Prevention of transmission of human immunodeficiency virus in Africa: effectiveness of condom promotion and health education among prostitutes.

Condom use was assessed after a programme of education about the acquired immunodeficiency syndrome and a condom distribution programme in a well-characterised prostitute population in Nairobi. Women received their education at group meetings (barazas) and at individual counselling sessions during which they were given the results of serological tests for the human immunodeficiency virus (group 1) or at barazas only (group 2), or through very little of either (group 3). During the counselling sessions free condoms were distributed. Before either of the programmes started, 10%, 9%, and 7% of groups 1, 2, and 3 women, respectively, reported occasional use of condoms. By November 1986, 80%, 70%, and 58% of groups 1, 2, and 3 women, respectively, reported at least some condom use. The mean frequency of condom use was 38.7 (SD 31.8)%, 34.6 (34.5)%, and 25.6 (29.5)% of sexual encounters in groups 1, 2, and 3 women. 20 of 28 women who were non-condom-users seroconverted compared with 23 of 50 women who reported some use of condoms.

Acquired Immunodeficiency Syndrome↗

Human immunodeficiency virus infection among men with sexually transmitted diseases. Experience from a center in Africa.

Heterosexual transmission of the human immunodeficiency virus (HIV) appears to occur readily in Africa but less commonly in North America and Europe. We conducted a case-control study among men attending a clinic for sexually transmitted diseases in Nairobi to determine the prevalence of HIV infection and the risk factors involved. HIV antibody was detected in 11.2 percent of 340 men who enrolled in the study. Reports of nonvaginal heterosexual intercourse and homosexuality were notably rare. Recent injections and blood transfusions were not associated with HIV infection. Travel and frequent contact with prostitutes were associated with HIV seropositivity. Men who were uncircumcised were more likely to have HIV infection (odds ratio, 2.7; P = 0.003), as were those who reported a history of genital ulcers (odds ratio, 7.2; P less than 0.001). A current diagnosis of genital ulcers was also associated with HIV seropositivity (odds ratio, 2.0; P = 0.028). Multivariate analysis revealed an independent association of genital ulcers with HIV infection in both circumcised and uncircumcised men. Uncircumcised men were more frequently infected with HIV, regardless of a history of genital ulcers. Our study finds that genital ulcers and an intact foreskin are associated with HIV infection in men with a sexually transmitted disease. Genital ulcers may increase men's susceptibility to HIV, or they may increase the infectivity of women infected with HIV. The intact foreskin may operate to increase the susceptibility to HIV.

Acquired Immunodeficiency Syndrome↗

Prophylaxis of gonococcal and chlamydial ophthalmia neonatorum. A comparison of silver nitrate and tetracycline.

We evaluated the use of silver nitrate drops and tetracycline ointment for the prophylaxis of ophthalmia neonatorum in a controlled trial involving 2732 newborns in Nairobi, Kenya. The overall rates of prevalence of intrapartum maternal gonococcal and chlamydial infection were 6.4 and 8.9 percent, respectively. After prophylaxis with silver nitrate, the incidence rates of gonococcal, chlamydial, and nongonococcal, nonchlamydial ophthalmia neonatorum were 0.4, 0.7, and 6.2 percent, respectively, whereas after prophylaxis with tetracycline, the rates were 0.1, 0.5, and 4.5 percent. The attack rates of gonococcal ophthalmia neonatorum in newborns exposed to Neisseria gonorrhoeae at birth were 7.0 percent in those receiving silver nitrate and 3.0 percent in those receiving tetracycline (95 percent confidence interval for the difference in rates, -3.4 to 11.4 percent). As compared with historical controls, the incidence of gonococcal ophthalmia neonatorum decreased 83 percent among infants treated with silver nitrate and 93 percent among those treated with tetracycline. Failure of prophylaxis was associated with postpartum maternal endometritis (P = 0.05). Among newborns exposed to maternal infection with Chlamydia trachomatis, chlamydial conjunctivitis developed in 10.1 percent given silver nitrate and in 7.2 percent given tetracycline (95 percent confidence interval for the difference in rates, -4.7 to 10.5 percent), yielding reductions in the incidence of chlamydial ophthalmia of 68 and 77 percent, respectively, as compared with the historical controls. We conclude that tetracycline is as effective as silver nitrate in preventing gonococcal ophthalmia neonatorum.

Chlamydia Infections↗

AIDS: an international perspective.

The acquired immunodeficiency syndrome (AIDS) and infection with the human immunodeficiency virus type 1 (HIV-1) constitute a worldwide public health problem. Whereas in Europe and in most of the Americas transmission of HIV-1 has occurred predominantly among homosexual men and intravenous drug abusers, in Africa a distinct epidemiologic pattern has emerged that indicates that HIV-1 infection is mainly heterosexually acquired. Heterosexual transmission appears to be increasing in some parts of Latin America and the Caribbean, and possibly in the United States. In addition to HIV-1, at least one other human retrovirus, namely HIV-2, has been implicated as a cause of AIDS in Africa and Europe. Factors that influence heterosexual transmission of HIV-1 include genital ulcerations, early or late stages of HIV-1 infection in the index case, and possibly oral contraception and immune activation. The rate of perinatal transmission is enhanced when the mother's illness is more advanced. AIDS and HIV-1 infection may have a significant impact not only on public health, but also on the demography and socioeconomic conditions of some developing countries. Programs for the prevention and control of AIDS should be an immediate priority in all countries.

Acquired Immunodeficiency Syndrome↗

Infection and disease after perinatal exposure to Chlamydia trachomatis in Nairobi, Kenya.

A cohort of 49 infants exposed to maternal chlamydial infection and 40 nonexposed infants was studied after birth for a mean of 3.3 +/- 1.5 and 3 +/- 1.7 mo, respectively. Eighteen (37%) exposed infants had at least one positive culture for Chlamydia trachomatis, whereas C. trachomatis was not isolated from any of the nonexposed infants. Eighteen (37%) exposed infants developed ophthalmia neonatorum (n = 12) or infant conjunctivitis (n = 7), compared with six (15%) of the nonexposed infants (P = .04). Six (12%) exposed infants developed pneumonia, compared with none of the 40 nonexposed infants (P = .05). One infant in the exposed group died during follow-up. These results suggest that appreciable infant morbidity in Kenya may be associated with the high prevalence of maternal chlamydial infection.

Chlamydia Infections↗

Genital ulceration as a risk factor for human immunodeficiency virus infection.

Among 115 heterosexual men who presented with genital ulcers to a sexually transmitted disease clinic in Nairobi, Kenya, the prevalence of serum antibody to HIV was 16.5%. A past history of genital ulcers was reported by 12 (63%) of 19 men with antibody to HIV versus 30 (31%) of 96 without antibody (P = 0.008). HIV infection was also positively associated with lack of circumcision, but was not associated with the etiology of the current genital ulcer. Logistic regression analysis (adjusted for age, number of recent sex partners, recent prostitute contact, circumcision, tribal ethnic identity, past history of urethritis, and current diagnoses) confirmed only the association between prior history of genital ulcer disease and HIV infection; (P = 0.04, odds ratio 2.35, 95% confidence limits, 1.01-5.47). The incidence of genital ulcers, particularly chancroid, is much higher in parts of Africa than in Europe or North America. This may contribute to the increased risk of heterosexual transmission of HIV in Africa. Aggressive control of chancroid and syphilis may offer one very feasible approach to reducing transmission of HIV in this region.

Acquired Immunodeficiency Syndrome↗