Peter H. Kilmarx

The Reemergence of Ebola Hemorrhagic Fever, Democratic Republic of the Congo, 1995

In May 1995, an international team characterized and contained an outbreak of Ebola hemorrhagic fever (EHF) in Kikwit, Democratic Republic of the Congo. Active surveillance was instituted using several methods, including house-to-house search, review of hospital and dispensary logs, interview of health care personnel, retrospective contact tracing, and direct follow-up of suspect cases. In the field, a clinical case was defined as fever and hemorrhagic signs, fever plus contact with a case-patient, or fever plus at least 3 of 10 symptoms. A total of 315 cases of EHF, with an 81% case fatality, were identified, excluding 10 clinical cases with negative laboratory results. The earliest documented case-patient had onset on 6 January, and the last case-patient died on 16 July. Eighty cases (25%) occurred among health care workers. Two individuals may have been the source of infection for >50 cases. The outbreak was terminated by the initiation of barrier-nursing techniques, health education efforts, and rapid identification of cases.

Successful introduction of routine opt-out HIV testing in antenatal care in Botswana.

Background:Botswana has high HIV prevalence among pregnant women (37.4% in 2003) and provides free services for prevention of mother-to-child transmission (PMTCT) of HIV. Nearly all pregnant women (>95%) have antenatal care (ANC) and deliver in hospital. Uptake of antenatal HIV testing was low from 1999 through 2003. In 2004, Botswanas President declared that HIV testing should be “routine but not compulsory” in medical settings. Methods:Health workers were trained to provide group education and recommend HIV testing as part of routine ANC services. Logbook data on ANC attendance, HIV testing, and uptake of PMTCT interventions were reviewed before and after routine testing training, and ANC clients were interviewed. Results:After routine testing started, the percentage of all HIV-infected women delivering in the regional hospital who knew their HIV status increased from 47% to 78% and the percentage receiving PMTCT interventions increased from 29% to 56%. ANC attendance and the percentage of HIV-positive women who disclosed their HIV status to others remained stable. Interviews indicated that ANC clients supported the policy. Conclusions:Routine HIV testing was more accepted than voluntary testing in this setting and led to substantial increases in the uptake of testing and PMTCT interventions without detectable adverse consequences. Routine testing in other settings may strengthen HIV care and prevention efforts.

Epidemiology of Syphilis in the United States, 1941–1993

Background and Objectives: The distribution and trends of syphilis are influenced by biologic factors, sexual behaviors, biomedical technology, availability of and access to health care, public health efforts, changes in population dynamics, and sociocultural factors. The objective of this article is to review the epidemiology of syphilis in the United States during the period 1941–1993 in the context of some of these factors. Study Design: Surveillance data on cases of syphilis and congenital syphilis reported by state and city health departments to the Centers for Disease Control and Prevention were analyzed to show distribution and trends by geographic location, racial and ethnic groups, gender, and age. Results: Historically, syphilis was distributed widely throughout the country and declined rapidly after the introduction of penicillin therapy and broad‐based public health programs, attaining its lowest levels in the 1950s. However, in recent years, the disease has returned and become focused in the southern region and in urban areas outside that region. Rates of syphilis have remained highest in black Americans, and the most recent national epidemic of syphilis primarily involved them. Rates in white men were at intermediate levels during the early 1980s but have declined to low rates in the 1990s, possibly because of changes in behavior in response to the AIDS epidemic. Rates in white women and other racial and ethnic groups have remained low throughout the 1980s and 1990s. Conclusions: Syphilis remains a significant problem in the United States, and its epidemiology is influenced by a complex combination of factors. To prevent and control syphilis effectively, public health practitioners must understand these factors and design programs and interventions that address the disease in the context of these factors.

Global epidemiology of HIV.

Purpose of reviewTo provide an update on the epidemiology of HIV worldwide and by region, along with an overview of recent HIV epidemiological research. Recent findingsThe global prevalence of HIV-1 has stabilized at 0.8%, with 33 million people living with HIV/AIDS, 2.7 million new infections, and 2.0 million AIDS deaths in 2007. Heterosexual spread in the general population is the main mode of transmission in sub-Saharan Africa, which remains the most heavily affected region, with 67% of the global burden. Male–male sex, injection drug use, and sex work are the predominant risk factors in most other regions. Infection rates are declining in some regions, including some of the most heavily affected countries in Africa, but climbing elsewhere such as in eastern Europe and central Asia. Recent HIV epidemiologic research findings include new insights into the role of HIV viral load, co-infection with sexually transmitted infections, male circumcision, antiretroviral treatment, serosorting, and superinfection in HIV transmission and prevention. SummaryThe global prevalence of HIV has stabilized in this decade, but with important regional differences in trends and modes of transmission. Prevention and treatment programs have an expanding impact in preventing HIV infection and AIDS deaths.

HIV-1 seroconversion in a prospective study of female sex workers in northern Thailand: continued high incidence among brothel-based women.

Objectives:To determine the incidence of HIV-1 infection, temporal trends in incidence, and risk factors for seroconversion in a cohort of female commercial sex workers (CSW) in upper northern Thailand, the region of Thailand with the highest rates of HIV-1 infection. Methods:CSW were enrolled from 1991 through 1994 and evaluated prospectively with interviews, physical examination, testing for sexually transmitted diseases (STD), and serologic testing for HIV-1 infection. Results:The incidence of HIV-1 seroconversion in the first year of follow-up was 20.3 per 100 person-years among 126 brothel-based CSW and 0.7 per 100 person-years among 159 other CSW who worked in other venues such as bars or massage parlors. Incidence remained elevated among brothel-based CSW who were enrolled later in the study compared with those who enrolled earlier. Through 1996, 30 women seroconverted. In a multivariable proportional hazards model, seroconversion was significantly associated (P < 0.05) with brothel-based sex work (adjusted risk ratio, 7.3) and Chlamydia trachomatis cervical infection (adjusted risk ratio, 3.3). Conclusion:Despite national HIV control efforts and declining rates of infection among young men in Thailand, brothel-based CSW may continue to be at high risk for HIV-1 infection. Additional efforts are needed to provide alternative economic choices for young women, to ensure universal condom use during commercial sex, and to develop new prevention technologies.

Early Diagnosis of Human Immunodeficiency Virus in Infants Using Polymerase Chain Reaction on Dried Blood Spots in Botswana's National Program for Prevention of Mother-to-Child Transmission

Background: Botswana has high antenatal human immunodeficiency virus (HIV) prevalence (33.4%). The public health system provides free services for prevention of mother to child transmission of HIV (PMTCT) and antiretroviral therapy, which can reduce vertical HIV transmission from 35% to <5%. Infant HIV diagnosis is challenging in resource-limited settings, and HIV prevalence among HIV-exposed infants in Botswana is unknown. Dried blood spot (DBS) polymerase chain reaction (PCR) provides a feasible method to assess PMTCT programs and identify HIV-infected children. Methods: We trained staff in 15 clinics and a hospital to obtain DBS on HIV-exposed infants age 6 weeks to 17 months receiving routine care. Samples were sent to the national HIV reference laboratory. Roche Amplicor 1.5 DNA PCR testing was performed. Results: Between June–December 2005, 1931 HIV-exposed infants age 6 weeks to 17 months were tested for HIV, of whom 136 (7.0%) were HIV infected. Among infants ≤8 weeks old, 27 of 544 (5.0%) were HIV infected. Among infants tested in clinics (primarily during routine health visits), 65 of 1376 (4.7%) were infected; among infants tested in the hospital, 71 of 555 (12.8%) were infected. Conclusions: Collection and testing of DBS was successfully integrated into routine infant care in the public health system. HIV prevalence among infants in the Botswana PMTCT program is low. National expansion of infant DBS PCR in Botswana is planned.

Sexual initiation, substance use, and sexual behavior and knowledge among vocational students in northern Thailand.

CONTEXT Thailand has undergone dramatic social changes in the last two decades, yet little is known about factors related to sexual initiation among adolescents. METHODS A survey using the audio computer-assisted self-interviewing method was conducted to assess social and demographic characteristics, substance use, sexual behavior, and knowledge of HIV and STIs among 1,725 vocational school students aged 15-21 living in northern Thailand. Gender differences for these factors were evaluated using chi-square and Mann-Whitney U tests. Multivariate survival analysis using Cox proportional hazards models assessed associations between these variables and sexual initiation for each gender. RESULTS Males initiated sexual intercourse at an earlier age than females (median ages of 17 and 18, respectively). At any given age, sexual initiation was associated with having a nonagricultural background and using alcohol or methamphetamine (adjusted rate ratios, 1.3-2.9). For males, initiation was also associated with having parents who did not live together, having a friend as a confidant, tobacco use, high perceived risk for HIV and high STI knowledge (1.3-1.7). For females, other factors associated with earlier initiation were younger age at interview, living away from family, lacking a family member as a confidant, high perceived risk for STIs and ever having smoked marijuana (1.3-2.4). CONCLUSIONS Interventions to ameliorate the adverse consequences of early sexual initiation need to address social influences such as parents and peer groups. Programs should identify and target high-risk subgroups, such as those who are sexually experienced at an early age and those engaged in patterns of generalized risk-taking.

Sociodemographic factors and the variation in syphilis rates among US counties, 1984 through 1993: an ecological analysis.

OBJECTIVES Syphilis in the United States is focally distributed, with high incidence rates in the South and in metropolitan areas nationwide. In this study an ecological analysis, using the county as the unit of analysis, was performed to generate hypotheses about community-level determinants of syphilis rates. METHODS Bivariate rank correlations and multivariate, backward stepwise elimination linear regressions were performed. Mean annual incidence of primary- and secondary-stage syphilis in a county was the dependent variable, and county sociodemographic characteristics (from census data) were the independent variables. RESULTS In the multivariate regression model, sociodemographic characteristics accounted for 71% of the variation in syphilis rates among counties. With other factors accounted for, the most highly correlated characteristics were percentage non-Hispanic Black population, county location in the South, percentage of the population that was urban, percentage Hispanic population, and percentage of births to women younger than 20 years. CONCLUSIONS Most of the variation in syphilis rates among counties is accounted for by sociodemographic characteristics. Identification and remediation of modifiable health determinants for which these factors are markers are needed to improve the health status of these populations.

Changes in the etiology of sexually transmitted diseases in Botswana between 1993 and 2002: implications for the clinical management of genital ulcer disease

BACKGROUND In recent years, increasing evidence has accumulated that suggests the majority of cases of genital ulcer disease in sub-Saharan Africa are due to viral and not bacterial infections. Although many cross-sectional studies support such a trend, few serial cross-sectional data are available to show the evolution of genital ulcer disease over time. METHODS We surveyed the prevalence of sexually transmitted diseases (STDs) among patients with STD symptoms and women recruited from family planning clinics in 3 cities in Botswana in 2002 and compared our findings with those from a survey of a similar population conducted in 1993. RESULTS The observed proportion of cases of genital ulcer disease due to chancroid decreased from 25% in 1993 to 1% in 2002, whereas the proportion of ulcers due to herpes simplex virus increased from 23% in 1993 to 58% in 2002. Although the proportion of ulcers due to syphilis was similar for both surveys, the rate of positive serologic test results for syphilis among patients with genital ulcer disease decreased from 52% in 1993 to 5% in 2002. During this period, decreases in the prevalence of gonorrhea, syphilis-reactive serologic findings, chlamydial infection, and trichomoniasis were also detected among patients with STDs and women from family planning clinics. These changes remained significant after estimates were adjusted for the sensitivity and specificity of diagnostic tests. CONCLUSIONS Our findings suggest a decrease in the prevalence of bacterial STDs and trichomoniasis, a reduction in the proportion of ulcers due to bacterial causes, and an increase in the proportion of ulcers due to herpes simplex virus during the period 1993-2002. These changes should be taken into consideration when defining new guidelines for the syndromic management of genital ulcer disease.

Safety and acceptability of the candidate microbicide Carraguard in Thai Women: findings from a Phase II Clinical Trial

Objective:To determine the safety and acceptability of vaginal application of Carraguard, a carrageenan-derived candidate microbicide gel. Design:A randomized, placebo-controlled, triple-blinded clinical trial was conducted in Chiang Rai, northern Thailand. Methods:Women were asked to insert one applicator of study gel vaginally at least three times per week (with or without sex) and to use gel with condoms every time they had sex. Safety was assessed by visual inspection of the vagina and cervix, changes in vaginal flora and self-reported symptoms at day 14, month 1 and then monthly for up to 1 year. Acceptability was assessed through reported use of the gel, return of used and unused applicators, and quarterly interviews. Results:One hundred sixty-five women were randomized: 83 to Carraguard and 82 to the placebo (methylcellulose gel) group. Study gel use was similarly high in both groups throughout the trial with an average of four applicators per week. Carraguard use was not associated with abnormal genital clinical findings, abnormal vaginal flora, Pap smear abnormalities or other abnormal clinical signs or symptoms. Adverse events were mostly mild, not attributed to gel use, and similarly distributed between groups. Participants in both groups reported high acceptability. Conclusions:Carraguard can safely be used an average of four times per week with or without sex and is acceptable to Thai women. A Phase III efficacy trial of Carraguard is warranted and is currently ongoing in South Africa.