Angus Nicoll

The epidemiology of HIV-1 infection in urban areas, roadside settlements and rural villages in Mwanza Region, Tanzania

ObjectiveTo determine the prevalence of HIV-1 infection and to identify the most important risk factors for infection. DesignA cross-sectional population survey carried out in 1990 and 1991 in Mwanza Region, Tanzania. MethodsAdults aged 15–54 years were selected from the region (population, 2 million) by stratified random cluster sampling: 2434 from 20 rural villages, 1157 from 20 roadside settlements and 1554 from 20 urban wards. Risk factor information was obtained from interviews. All sera were tested for HIV-1 antibodies using enzyme-linked immunosorbent assay (ELISA); sera non-negative on ELISA were also tested by Western blot. ResultsThe response rate was 81%. HIV-1 infection was 1.5 times more common in women than in men; 2.5% of the adult population in rural villages, 7.3% in roadside settlements and 11.8% in town were infected. HIV-1 infection occurred mostly in women aged 15–34 years and men aged 25–44 years. It was associated with being separated or widowed, multiple sex partners, presence of syphilis antibodies, history of genital discharge or genital ulcer, travel to Mwanza town, and receiving injections during the previous 12 months, but not with male circumcision. ConclusionThis study confirms that HIV-1 infection in this region in East Africa is more common in women than in men. The results are consistent with the spread of HIV-1 infection along the main roads. There is no evidence that lack of circumcision is a risk factor in this population.

Are trends in HIV, gonorrhoea, and syphilis worsening in western Europe?

The prevalence of gonorrhoea and syphilis, and that of HIV infection among heterosexuals, has been increasing in many European countries since 1995. Angus Nicoll and Francoise Hamers make a case for introducing surveillance of sexually transmitted infections other than HIV at a European level #### Summary points Trend data show that the numbers of new diagnoses of sexually acquired HIV infections increased by 20% in western Europe between 1995 and 2000 Gonorrhoea reports have increased in France, the Netherlands, Sweden, Switzerland, and the United Kingdom The Netherlands, France, Ireland, and the United Kingdom reported outbreaks of syphilis in men having sex with men, including men already infected with HIV These preliminary data for several European countries imply that people may increasingly take sexual risks HIV remains Europes most important sexually transmitted infection, yet complacency over HIV prevention may have set in among individuals, populations, and some governments in western Europe As a consequence of AIDS prevention campaigns in the late 1980s and the early 1990s, the numbers of new reported diagnoses of gonorrhoea, infectious syphilis, and other sexually transmitted infections fell in several countries in western Europe.1 The downward trends in gonorrhoea seen in England and Wales, France, the Netherlands, and Sweden (fig 1) were typical and paralleled reports of declining levels of sexual behaviours with a high risk of transmitting infection.2 Available data indicate that the campaigns seem to have been successful in either reducing transmission of HIV or preventing it from rising as much as it did in countries that did not have early interventions.3 In Europe at the start of the 21st century, HIV remains the most serious sexually transmitted infection. An estimated 540 000 west Europeans have an infection that remains incurable and the cost of treating a single adult once discounting for time is undertaken …

A community trial of the impact of improved sexually transmitted disease treatment on the HIV epidemic in rural Tanzania: 1. Design.

ObjectiveTo describe the rationale, and design of a randomized trial of the impact of improved services for the treatment of sexually transmitted diseases (STD) on the incidence of HIV infection in Mwanza Region, Tanzania. MethodsThe likely impact of improved STD treatment services on HIV incidence, and the need for empirical information on the effectiveness of this intervention strategy, are discussed. The rationale, and design of such an intervention programme in Mwanza Region, and of a community-randomized trial to measure the impact of the programme on HIV, and other STD, are presented. Problems in the design, and interpretation of the trial are reviewed. ResultsResults of the baseline survey of the cohort of over 12000 adults in 12 communities are presented in a companion paper. ConclusionThere is an urgent need for effective preventive measures against the HIV epidemic in sub-Saharan Africa, and other developing regions. Improved STD treatment has been promoted as a potentially effective strategy, but there is little empirical information on its impact. The trial in Mwanza Region is the first randomized study of this intervention, and should provide valuable data for health policy makers.

Bacterial vaginosis: a public health review.

In the UK bacterial vaginosis is one the conditions most commonly associated with an abnormal vaginal discharge in reproductive age women. Bacterial vaginosis is a polymicrobial syndrome in which the normal vaginal lactobacilli, particularly those producing hydrogen peroxide, are replaced by a variety of anaerobic bacteria and mycoplasmas. Common agents of bacterial vaginosis include Gardnerella vaginalis, Mobiluncus, Bacteroides spp. and Mycoplasma hominis. The wide range of possible aetiologies is re ̄ected in the variation in symptoms associated with bacterial vaginosis: these include grey, homogenous vaginal discharge; odorous discharge (®shy smell); increased discharge without an in ̄ammatory response; yellow discharge; abdominal pain; intermenstrual bleeding; menorrhagia or prolonged menses. Up to 50% of women are asymptomatic. This variation is captured by the clinical de®nition of bacterial vaginosis requiring three of the four composite criteria to be met

Selective versus universal antenatal HIV testing : Epidemiological and implementational factors in policy choice

OBJECTIVE To develop an epidemiological basis for economic analyses of selective and universal antenatal screening strategies, and to apply it to the UK. METHODS The prevalence of higher-risk women and the prevalence of undiagnosed infection within groups of high-risk and low-risk women was estimated from surveillance and survey data. The numbers of women tested and the numbers of infected women who would be identified by universal and selective strategies were then calculated under a range of assumptions about the identification of higher-risk women and acceptance of testing. RESULTS In higher-risk women estimated prevalence of undiagnosed infection was between 0.06% and 2.8%, comparing well with independent estimates. In low-risk women, estimates ranged from 0.014% in London to 0.002% in the rest of the UK. If uptake among the high-risk women was the same in selective and universal strategies, universal testing would entail testing between 7100 (London) and 50000 (rest of England) additional women to detect an additional case. However, if selective screening identified only 60% of those at high risk and achieved only 60% acceptance compared with a universal programme, then universal screening would require only 1150 additional women to identify one additional case in London, compared to 6470 in Scotland and 13140 in the rest of the UK. CONCLUSIONS Overall prevalence does not form an adequate basis for determining screening strategy. Instead, universal screening can be justified either because the prevalence of HIV in the low-risk group is sufficiently high, or because it achieves sufficiently higher uptake relative to selective screening among those at higher risk.

Sentinel surveillance for HIV-1 among pregnant women in a developing country: 3 years' experience and comparison with a population serosurvey.

ObjectivesTo establish unlinked, anonymous sentinel surveillance for HIV-1 among pregnant women attending an antenatal clinic, to determine age-specific seroprevalences, to monitor trends and to compare seroprevalence with that detected by a population serosurvey. To establish the sustainability and costs of surveillance. DesignSentinel surveillance for HIV through serial collection of unlinked, anonymous seroprevalence data from antenatal care; comparison of sentinel data with those from a population serosurvey; financial and general audit of the sentinel surveillance. SettingA community antenatal clinic in a large urban centre, Mwanza Municipality, Tanzania, eastern Africa, between October 1988 and September 1991. PatientsPregnant women attending for antenatal care. Main outcome measureAge-specific HIV-1 seroprevalences, trends over time, difference from age-specific population seroprevalences, sustainability and costs. ResultsOverall HIV-1 seroprevalence was 11.5% (95% confidence interval, 10.5–12.4); differences in age-specific prevalences were not significant. There was no clear evidence of change in seroprevalence over the study period in any age group, although there was some indication of a rise in some age groups in 1988–1989. Sentinel surveillance among pregnant women may have significantly underestimated population HIV-1 seroprevalence for women under the age of 35 years. HIV-1 surveillance proved feasible and sustainable. Additional recurrent costs were US

Assessing the impact of national anti-HIV sexual health campaigns: trends in the transmission of HIV and other sexually transmitted infections in England.

1.7 per specimen for unlinked anonymous testing and US

Evidence base of incubation periods, periods of infectiousness and exclusion policies for the control of communicable diseases in schools and preschools.

0.57 per woman for syphilis screening. ConclusionsHIV-1 seroprevalence did not change significantly over 3 years, probably implying a substantial incidence of HIV-1 infection. In this setting seroprevalence in pregnant women may have underestimated population seroprevalence in women aged under 35 years. With modest inputs and good organization unlinked anonymous HIV-1 sentinel surveillance of pregnant women can be introduced and sustained in an African setting. This may usefully be carried out in conjunction with syphilis screening.

A population-based study of syphilis and sexually transmitted disease syndromes in north-western Tanzania. 2. Risk factors and health seeking behaviour.

Objective: To assess the impact of the sexual component of AIDS and HIV campaigns on transmission of HIV and other sexually transmitted infections (STIs). Design: Comparison of time series data. Setting: England, 1971–1999. Outcome measures: HIV transmission and diagnoses among men who have sex with men (MSMs), rates of attendances and specific STI diagnoses (per 100 000 total population) at genitourinary medicine (GUM) clinics. Results: Awareness of AIDS and campaigns in 1983–4 among homosexual men coincided with substantial declines in transmission of HIV and diagnoses of syphilis among MSMs. During general population campaigns in 1986-7 new GUM clinic attendances requiring treatment fell by 117/105 in men and 42/105 in women. Rates for gonorrhoea fell by 81/105 and 43/105 and genital herpes by 6/105 and 4/105, respectively. Previous rises in genital wart rates were interrupted, while rates of attendances not requiring treatment (the “worried well”) increased by 47/105 and 58/105 for men and women, respectively. Since 1987 diagnoses of HIV among MSMs have not declined, averaging 1300–1400 annually. Following a period of unchanging rates there have been substantial increases in GUM attendances requiring treatment, notably for gonorrhoea, syphilis, and viral STIs since 1995. Conclusions: Self help initiatives and awareness among homosexual men in 1983–4 contributed significantly to a fall in HIV transmission among MSMs, and the general campaigns of 1986–7 were associated with similar effects on all STI transmission. Both effects seem to have occurred through changing sexual behaviour, and probably contributed to the UKs low national HIV prevalence. Bacterial STI incidence has increased significantly since 1995 and there is no evidence that recent prevention initiatives have reduced HIV transmission among MSMs, hence sexual health initiatives need to be comprehensively reinvigorated in England.

The public health significance of HIV-1 subtypes.

Background. The optimal control of communicable diseases requires accurate information on incubation periods, periods of infectiousness and the effectiveness of exclusion. We collected the available evidence for a wide range of infections and infestations and produced evidence-based guidelines for their control in schools and preschools. Methods. A thorough MEDLINE literature search was conducted on the incubation period, period of infectiousness and effectiveness of exclusion for 41 infections. The quality of the information obtained was indicated by levels of evidence. The information was used to produce guidelines on exclusion, and the recommendations were graded according to the levels of evidence available. Grades A, B and C represented strongly, reasonably and poorly evidence-based recommendations, respectively. Results. The quality of data obtained was highly variable. Information on incubation periods was obtained for all 41 infections and was generally of good quality. Information on periods of infectiousness and effectiveness of exclusion was of a lesser quality and was found for only 11 and 4 conditions, respectively. There were 3 Grade A, 17 Grade B and 21 Grade C recommendations on exclusion. Examples of exclusion periods include: 5 days for chickenpox, measles, mumps, rubella, pertussis and scarlet fever; and 24 h from the cessation of diarrhea for most gastrointestinal diseases. In contrast to existing guidelines exclusion was not recommended for school age children with hepatitis A. Conclusions. We have been able to present the best available data on the incubation periods and periods of infectiousness of 41 childhood infections. It was possible to produce strongly or reasonably evidence-based guidelines on exclusion periods for approximately one-half of the infections.