Epidemiology Of HIV Infection Research Articles

The epidemiology of HIV infection among young people aged 15–24 years in southern Africa

To investigate epidemiological patterns and trends of HIV infection and sexual behaviour among young people aged 15-24 years in the nine countries in southern Africa most affected by the HIV epidemic. Data on HIV prevalence among young people in the general population were obtained from national population-based surveys conducted between 2000 and 2007, whereas data on sexual behaviour were obtained from repeat surveys between 1994 and 2007. Linear or exponential regression was used to analyse HIV prevalence trends among young women attending antenatal clinics in recent years. Patterns of HIV infection among young people are similar across the countries included in this analysis. The prevalence of HIV increases after the age of 15 years, more rapidly among women than among men, reaching a peak among women in their twenties and men in their thirties. Between 2000 and 2007 the prevalence of HIV among antenatal clinic attendees was constant in Mozambique and South Africa and declining in Lesotho, Namibia, Swaziland, Zambia, Botswana, Malawi and Zimbabwe, but only reached statistical significance (P < 0.05) in the last three. Changes towards safer sexual behaviour were observed over time among young men and women in the general population in this region. Sexual behaviour changes among young people are encouraging and are associated with declines in HIV prevalence among young antenatal clinic attendees over time. More research is needed to understand the recent changes and the very high prevalence among young women in this region. Interventions aimed at reducing risky behaviour need to be supported and expanded while incorporating new approaches to prevention.

The epidemiology of HIV infection in Zambia

Population surveys of health and fertility are an important source of information about demographic trends and their likely impact on the HIV/AIDS epidemic. In contrast to groups sampled at health facilities they can provide nationally and regionally representative estimates of a range of variables. Data on HIV-sero-status were collected in the 2001 Zambia Demographic and Health Survey (ZDHS) and made available in a separate data file in which HIV status was linked to a very limited set of demographic variables. We utilized this data set to examine associations between HIV prevalence, gender, age and geographical location. We applied the generalized geo-additive semi-parametric model as an alternative to the common linear model, in the context of analyzing the prevalence of HIV infection. This model enabled us to account for spatial auto-correlation, non-linear, location effects on the prevalence of HIV infection at the disaggregated provincial level (nine provinces) and assess temporal and geographical variation in the prevalence of HIV infection, while simultaneously controlling for important risk factors. Of the overall sample of 3950, 54% was female. The overall HIV-positivity rate was 565 (14.3%). The mean age at HIV diagnosis for male was 30.3 (SD=11.2) and 27.7 (SD=9.3) for female respectively. Lusaka and Copperbelt have the first and second highest prevalence of AIDS/HIV (marginal odds ratios of 3.24 and 2.88, respectively) but when the younger age of the urban population and the spatial auto-correlation was taken into account, Lusaka and Copperbelt were no longer among the areas with the highest prevalence. Non-linear effects of age at HIV diagnosis are also discussed and the importance of spatial residual effects and control of confounders on the prevalence of HIV infection. The study was conducted to assess the spatial pattern and the effect of confounding risk factors on AIDS/HIV prevalence and to develop a means of adjusting estimates of AIDS/HIV prevalence on the important risk factors. Controlling for important risk factors, such as geographical location (spatial auto-correlation), age structure of the population and gender, gave estimates of prevalence that are statistically robust. Researchers should be encouraged to use all available information in the data to account for important risk factors when reporting AIDS/HIV prevalence. Where this is not possible, correction factors should be applied, particularly where estimates of AIDS/HIV prevalence are pooled in systematic reviews. Our maps can be used for policy planning and management of AIDS/HIV in Zambia.

Start Talking About Risks: development of a Motivational Interviewing-based safer sex program for people living with HIV.

The epidemiology of HIV infection in the US in general, and in the southeast, in particular, has shifted dramatically over the past two decades, increasingly affecting women and minorities. The site for our intervention was an infectious diseases clinic based at a university hospital serving over 1,300 HIV-infected patients in North Carolina. Our patient population is diverse and reflects the trends seen more broadly in the epidemic in the southeast and in North Carolina. Practicing safer sex is a complex behavior with multiple determinants that vary by individual and social context. A comprehensive intervention that is client-centered and can be tailored to each individual's circumstances is more likely to be effective at reducing risky behaviors among clients such as ours than are more confrontational or standardized prevention messages. One potential approach to improving safer sex practices among people living with HIV/AIDS (PLWHA) is Motivational Interviewing (MI), a non-judgmental, client-centered but directive counseling style. Below, we describe: (1) the development of the Start Talking About Risks (STAR) MI-based safer sex counseling program for PLWHA at our clinic site; (2) the intervention itself; and (3) lessons learned from implementing the intervention.

Risk factors for HIV infection in Males who have Sex with Males (MSM) in Bangladesh

BackgroundRecent surveillance data from Bangladesh indicate rising HIV infection among intravenous drug users (IDU) in the country. We suggest a likely association between HIV risk factors in this group and other groups, such as males who have sex with males (MSM).MethodsData on MSM in Bangladesh was collected and analyzed from numerous primary and secondary sources, including government ministries, non-profit health organizations, and personal communications.ResultsThe overall prevalence of HIV in Bangladesh is relatively low, but surveillance data indicate that infection has reached significant proportions in certain high-risk groups and may soon spread to other groups, specifically MSM.ConclusionThe epidemiology of HIV infection in other countries suggests that increasing rates of HIV in higher-risk populations can precede an epidemic in the general population. We review the data concerning MSM, IDU and HIV in Bangladesh from a variety of sources and propose ways to prevent HIV transmission.

Prevention of mother to child transmission of HIV infection in Pacific countries

A generalized epidemic of HIV infection has been evolving in Papua New Guinea over the last decade, whereas in other Pacific Island countries and territories (PICT) HIV transmission has generally been less widespread. Programmes to detect HIV infection in pregnant women and to prevent mother to child transmission (MTCT) during either delivery or breast-feeding can decrease the incidence of infection in infants. The limited health infrastructure present in some PICT may delay the implementation of effective programmes to decrease MTCT of HIV. We used a standardized questionnaire to survey health-care providers in 22 PICT for information on the epidemiology of HIV infection and strategies used during 2004 to prevent MTCT of HIV infection in their country. We supplemented these survey responses with data obtained from regional organizations supporting national responses to HIV. We obtained responses from 21 PICT. The reported prevalence of known HIV infection was >150 per 100 000 persons in Papua New Guinea, approximately 100 per 100 000 persons in French Polynesia, Guam, New Caledonia and Tuvalu and <50 per 100 000 persons in the remaining 14 PICT. Other than in Papua New Guinea, where an estimated 500 pregnant women had HIV infection diagnosed in 2004, reported HIV infection among pregnant women was rare. Ten PICT reported that an HIV antibody test was offered as a routine component of antenatal care and 11 reported that antiretroviral medications were available for the prevention of MTCT of HIV infection. The prevalence of HIV infection differs greatly between PICT with a varying risk of MTCT of HIV infection. Successful prevention of MTCT of HIV infection throughout the PICT will require improved uptake of antenatal HIV antibody testing and better access to antiretroviral medications.

HIV: Infection Control Issues For Oral Healthcare Personnel

To present the essential elements of an infection control/exposure control plan in the oral healthcare setting with emphasis on HIV infection. A comprehensive review of the literature was conducted with special emphasis on HIV-related infection control issues in the oral healthcare setting. Currently available knowledge related to HIV-related infection control issues is supported by data derived from well-conducted trials or extensive, controlled observations, or, in the absence of such data, by best-informed, most authoritative opinion available. Essential elements of an effective HIV-related infection control plan include: (1) education and training related to the etiology and epidemiology of HIV infection and exposure prevention; (2) plans for the management of oral healthcare personnel potentially exposed to HIV and for the follow-up of oral healthcare personnel exposed to HIV; and (3) a policy for work restriction of HIV-positive oral healthcare personnel. While exposure prevention remains the primary strategy for reducing occupational exposure to HIV, knowledge about potential risks and concise written procedures that promote a seamless response following occupational exposure can greatly reduce the emotional impact of an accidental needlestick injury.

HIV INFECTION AMONG COMMERCIAL SEX WORKERS AND INJECTING DRUG USERS IN THE CZECH REPUBLIC

Since the first HIV case was diagnosed in the Czech Republic in 1985, there is a lack of information regarding the epidemiology of HIV infection in most high-risk groups. To determine the prevalence of, and risk factors for, HIV among female and male commercial sex workers (FCSW and MCSW, respectively) and injecting drug users (IDUs), cross-sectional studies were conducted in the cities of Cheb, Usti nad Labem, Ostrava, and Prague of the Czech Republic. A total of 1,277 subjects were enrolled, which included 585 FCSWs, 230 MCSWs, and 462 IDUs. The HIV prevalences were 0.7% (95% CI: 0.2-1.7%), 0.9% (95% CI: 0.1-3.1%), and 0.2% (95% CI: 0.005-1.2%) among FCSWs, MCSWs, and IDUs, respectively. Although low HIV prevalences were found, ongoing sentinel surveillance studies, which address modifiable behavioral and biologic risk factors among high-risk groups, are necessary to guide strategies to stem the tide of the epidemic in this country.

Transmission and Epidemiology of HIV/AIDS: a Global View

Since the first recognition of the condition that is now called AIDS, much has been learned. We now know that AIDS results from infection with HIV types 1 and 2. Advancements in approaches to treatment, in the form of new types of medications, have changed the trajectory of illness by slowing progression and decreasing the incidence of HIV-associated opportunistic infections in the millions of people living with HIV infection, particularly in developed countries. In less developed areas of the world, HIV infection looks different, in part because of the differential availability of medications and health care. This article focuses on epidemiology of HIV infection and AIDS in the United States and worldwide, and on transmission, including susceptibility factors.

Epidemiology of HIV-1 Infection in Agricultural Plantation Residents in Kericho, Kenya

A cross-sectional study was performed to determine the prevalence and risk factors for HIV-1 infection among agricultural plantation residents in Kericho, Kenya. Volunteers were recruited, interviewed, and phlebotomized for HIV-1 serologic testing. Sex-specific adjusted odds ratios were estimated using logistic regression. The overall HIV-1 prevalence was 9.9% (81/820), with prevalence in women more than twice that in men (17.4% vs 8.0%, P=0.001). Among men, elevated HIV-1 prevalence was seen with increasing age, peaking in those older than 30 years (10.3%), marriage (10.4%), Luo tribe affiliation (23.5%), employment (8.9%), travel (11.0%), and being uncircumcised (29.2%). Among women, elevated HIV-1 prevalence was seen in those with no formal education (36.8%) and those who received goods in exchange for sex (36.0%). More than 97% of volunteers expressed a willingness to participate in future HIV-1 studies requiring semiannual visits. HIV prevention efforts have been implemented, along with further research to characterize this population for future cohort feasibility studies and HIV-1 vaccine efficacy trials.

Influence of highly active antiretroviral therapy on persistence of HIV in the central nervous system

The epidemiology of HIV infection is changing rapidly in the era of highly actively antiretroviral therapy, as the use of such therapy is increasing in all countries. This has had a significant impact on the neurological manifestations of HIV infection, posing new challenges in diagnosis and treatment. This review provides a critical analysis of the recent literature on the impact of highly actively antiretroviral therapy on HIV-related neurological complications and changes in treatment strategies. It is becoming clear that the brain is an important reservoir for the virus, and neuroinflammatory and neurodegenerative changes may continue despite the adequate use of highly actively antiretroviral therapy. Although this antiretroviral therapy has had a significant impact on the severity of HIV dementia, cognitive impairment persists. With improvement in the immune status following treatment with antiretrovirals, in rare cases the brain can become a target of the immune reconstitution. Highly actively antiretroviral therapy may need to be optimized in patients with HIV-associated cognitive impairment to achieve maximal central nervous system penetration; however, this therapeutic strategy may not be sufficient for halting the process. In some instances, the antiretroviral drugs themselves may become the problem. New strategies for neuroprotection that also target host genes which control HIV replication are being developed.

The epidemiology of HIV-1 infection in northern Tanzania: Results from a community-based study

We conducted a community-based study to determine the predictors of HIV-1 among women aged 20–44 years (N = 1,418) and their regular male partners (N = 566) from randomly selected households in Moshi, Tanzania. The weighted prevalence of HIV-1 was 10.3% in women and 7% in men. The highest risk of HIV-1 was in subjects whose partners were HIV-1 seropositive in both women (adjusted odds ratio (AOR) = 26.63; 95% confidence interval (CI): 10.74–66.02) and men (AOR = 22.25; 95%CI: 7.06–70.15). Herpes simplex virus type 2 (HSV-2) and Mycoplasma genitalium were also significantly associated with HIV-1. Women with male partners ≥12 years older than themselves had increased risk of HIV-1 (AOR = 1.99; 95%CI: 1.01–7.85). Other predictors of HIV-1 were history of infertility and the number of sex partners in the last three years in women and the age at time of circumcision and history of past sexually transmitted diseases (STDs) in male partners. These findings show that HIV-1/STDs were major public health problems among women and their long-term partners in this population. HIV-1 prevention efforts should include promotion of couple's HIV-1 counseling and testing services, control of HSV-2, promotion of safer sexual practices and strategies to reduce the age difference between women and their partners.

Epidemic of HIV Coupled With Hepatitis C Virus Among Injecting Drug Users of Himalayan West Bengal, Eastern India, Bordering Nepal, Bhutan, and Bangladesh

A study was conducted in June 2004 to find out the epidemiology of HIV infection among injecting drug users (IDUs) of Darjeeling District of West Bengal, eastern India. The district headquarter, Darjeeling town, also known as “Queen of Hills,” is a beautiful spot situated in Himalayan West Bengal that attracts a large number of tourists each year from all over the world. Another unique feature of the district is that it has international boundaries with three countries, Nepal, Bhutan, and Bangladesh. Siliguri, the part of the district on plains, acts as a transit station for these countries as well as to the entire Himalayan region of West Bengal and neighboring state, Sikkim. It is also a transit point to all northeastern states of India: Assam, Arunachal Pradesh, Nagaland, Manipur, Mizoram, Meghalaya, and Tripura. Two hundred twenty-eight study subjects (IDUs) were included in this community-based cross-sectional study from all four subdivisions of the district. Informed consent was obtained, and then personal interviews, followed by blood testing were performed using unlinked anonymous procedure. The study revealed that overall HIV seroprevalence among IDUs was 11.8% (n = 27; 95% confidence interval, 7.9–16.7), whereas seroprevalence of hepatitis C was found to be 47.7% (n = 97). Prevalence of HIV was higher in subjects from hill districts (13.5%) compared with subjects from the plains (9.2%). It also revealed that most IDUs (75.3%) used “brown sugar,” an impure form of heroin, as their major addictive substance followed by injection norphine. Sharing of injecting equipment was found to be as high as 67% among IDUs, and sharing of drugs from common ampules was found to be 35.5% of the studied subjects (n = 93). Most subjects (96%) were found to clean their injecting paraphernalia with plain water. Most IDUs (98%) were found to inject intravenously. About 52% of IDUs visited sex workers one or more times within the last 1 year, and 15% of the interviewed subjects (n = 93) reported to suffer from sexually transmitted diseases during the same period. All the IDUs knew about HIV/AIDS. About 69% of the subjects knew that apparently healthy looking person might have HIV infection. HIV was found to be associated significantly with age of the injectors and duration of injecting practices. The study revealed the epidemic of HIV and hepatitis C among IDU populations at this bordering district of West Bengal for the first time that requires urgent intervention at local, national, and international levels.

Epidemiology of HIV infection among brothel-based sex workers in Kolkata, India.

A cross-sectional study was carried out during January-June 2004 to assess the status of HIV infection among brothel-based sex workers in Kolkata city, India. Six hundred and twenty-two sex workers, selected from six brothels, were included in the study to assess their HIV status, and 362 sex workers, a subset of the above population, were interviewed to study their risk behaviour and practices. Blood samples were collected from each sex worker for testing HIV by an unlinked anonymous method. The prevalence of HIV infection was 9.6%, but was much higher among younger sex workers aged 20 years or less (27.7%) compared to the older age group (8.4%). This difference was statistically significant, indicating an association of younger ages with HIV infection [p = 0.006 and odds ratio (OR) = 4.18; (95% confidence interval (CI) 1.2-13.8)]. HIV was not associated with duration of sex work, average number of clients entertained per day, condom use, practice of sex during menstruation, pre-coital examination of penis for visible ulcer/discharge, suffering from sexually transmitted infections, and entertaining clients outside the brothel. There was a big gap between the reported and the evaluated condom use by sex workers. The results suggest that there is a need to develop suitable HIV intervention strategies, considering the socioeconomic and cultural aspects of city sex workers, with a provision for continuous monitoring and evaluation.

Características clínicas y epidemiológicas de la infección por el VIH en extranjeros en Elche, España (1998-2003)

To determine the characteristics of HIV-infection in foreign patients residing in Elche, Spain. A retrospective comparative analysis of clinical and epidemiological characteristics was performed to study HIV-infection in foreign immigrants, foreigners who were not immigrants and the native Spanish population between January 1998 and December 2003. Among the 659 patients attended, 30 (4.6%) were foreign immigrants and 11 (1.7%) foreign non-immigrants. The percentage of affected immigrants increased during the study period from 1.6% to 9.8% (p < 0.001). There was a higher percentage of women in the immigrant group (36.7%) than in the foreign non-immigrant (27.3%) and native (18.4%) groups (p = 0.04). Mean age of the immigrants was lower than that of the foreign non-immigrants and native population (p = 0.02). Sexual transmission as a risk factor for acquiring HIV infection was higher in the immigrant (80%) group than in the foreign non-immigrant (27.3%) and native populations (14.7%), (p = 0.005). Antiretroviral treatment and mortality were similar in immigrant and non-immigrant patients. The epidemiology of HIV infection in foreign patients was different from that observed in the native population, but access to antiretroviral treatment and mortality were similar.

Is there an epidemic of HIV Infection in the US ESRD program?

Surveys revealed increases in the prevalence of HIV-infected patients in the US end-stage renal disease (ESRD) program in the 1980s and early 1990s, with clustering in young black men 25 to 44 yr old. Since the availability of highly active antiretroviral therapy in 1996, the prognosis of HIV-infected patients has improved, and therapy has been shown to change the course of classic HIV-associated nephropathy. We used the United States Renal Data System database to determine if the incidence and prevalence of HIV-infected patients with renal disease has increased in the ESRD program, by means of principal diagnoses and comorbid AIDS-defining diagnoses. As the number of US patients living with AIDS increased 57% from 214,711 in 1995 to 337,017 in 2000, and the number of incident ESRD patients increased 29.9% from 72,827 to 94,602, the number of incident HIV-infected patients increased only by 3.5%, from 1133 to 1171. Over this time, the percentage of incident ESRD patients with HIV infection fell from 1.56% to 1.24%. Among black men 25 to 44 yr of age, HIV infection as a proportion of incident ESRD cases fell from 8.5% to 6.2% from 1995 to 2000. The incident rate per million of AIDS or HIV infection in black men aged 25 to 44 fell from 107 in 1995 to 78 per million in 2000. The incidence rate for HIV-infected women in the ESRD program rose 14% while it declined 7% in men. Almost 2000 HIV-infected women, or 28.8% of the population, have initiated therapy for ESRD with hemodialysis. The number of prevalent cases increased in absolute numbers 81.3% from 2687 to 4871 (0.90% to 1.16% of the ESRD program). One-year survival rates for HIV-infected incident ESRD patients increased from 53.1% to 67.1% from 1995 to 2000. Although these values may be underestimates because of underreporting due to confidentiality concerns and lack of biopsy confirmation, we conclude that although the prevalence of HIV infection is increasing in the US ESRD population, the increase as a proportion of the program is minimal and is due to better survival after development of renal failure. The incidence of HIV infection in the US ESRD program is stable. Highly active antiretroviral therapy may be responsible for the change in epidemiology of HIV infection in the US ESRD program.

AIDS, individual behaviour and the unexplained remaining variation

From the start of the AIDS pandemic, individual behaviour has been put forward, implicitly or explicitly, as the main explanatory concept for understanding the epidemiology of HIV infection and in particular for the rapid spread and high prevalence in sub-Saharan Africa. This has had enormous implications for the international response to AIDS and has heavily influenced public health policy and strategy and the design of prevention and care interventions at national, community and individual level. It is argued that individual behaviour alone cannot possibly account for the enormous variation in HIV prevalence between population groups, countries and regions and that the unexplained remaining variation has been neglected by the international AIDS community. Biological vulnerability to HIV due to seriously deficient immune systems has been ignored as a determinant of the high levels of infection in certain populations. This is in sharp contrast to well proven public health approaches to other infectious diseases. In particular, it is argued that poor nutrition and co-infection with the myriad of other diseases of poverty including tuberculosis, malaria, leishmaniasis and parasitic infections, have been neglected as root causes of susceptibility, infectiousness and high rates of transmission of HIV at the level of populations. Vulnerability in terms of non-biological factors such as labour migration, prostitution, exchange of sex for survival, population movements due to war and violence, has received some attention but the solutions proposed to these problems are also inappropriately focused on individual behaviour and suffer from the same neglect of economic and political root causes. As the foundation for the international community's response to the AIDS pandemic, explanations of HIV/AIDS epidemiology in terms of individual behaviour are not only grossly inadequate, they are highly stigmatising and may in some cases, be racist. They have diverted attention from poverty and powerlessness as root causes of vulnerability to infection and as such they are a waste of scarce resources. A return to a basic needs approach to all the diseases of poverty is nothing more than proven public health wisdom and experience. A sustainable and meaningful response to AIDS is simultaneously a sustainable and meaningful response to all the diseases of poverty. The obstacles to the adoption of this approach are economic and political and must be confronted at the level of international financial institutions, the globalisation of neoliberal economic systems, the growing power imbalances between and within nations and the undermining of democracy and national sovereignty. An alternative strategy for AIDS and the other diseases of poverty would build on macroeconomic reforms for a fair, rational and sustainable international economic order so that democratically elected governments may meet their people's basic needs, including health, without external interference.

First molecular characterization of HIV-1 Tunisian strains.

In order to identify HIV-1 subtypes circulating in Tunisia, blood specimens from 25 HIV-1 infected Tunisian patients were collected. Proviral HIV-1 DNA was genotyped by sequence analysis of the C2-V3 env region. HIV-1 subtypes were determined in 21 DNA sequences: 20 were of subtype B and one was a circulating recombinant form (CRF02 AG). Subtype B largely dominates the epidemiology of HIV-1 infection in Tunisia, suggesting the probable imported origin of HIV-1 infection, but further studies are needed to investigate the potential diversification of HIV-1 isolates in Tunisia.

Temporal trends and molecular epidemiology of HIV-1 infection in Taiwan from 1988 to 1998.

Eight hundred and seventy-nine HIV-1-infected patients (comprising 46% of reported HIV-1/AIDS cases in Taiwan) were recruited for this study of the molecular epidemiology of HIV-1 in Taiwan from 1988 to 1998. HIV-1 subtypes were determined using a modified peptide-enzyme immunoassay complemented with DNA sequencing and phylogenetic analysis. Of the 807 HIV-1 infected men, 68.2% were infected with HIV-1B, 29.5% with HIV-1 circulating recombinant form (CRF)01_AE and 2.3% with other subtypes. Of the 72 HIV-1-infected women, 72.2% were infected with HIV-1 CRF01_AE, 13.9% with HIV-1B, and 13.9% with other subtypes. All of 8 foreign-born, Southeast Asian women and 6 of 7 (85.7%) Taiwan-native female commercial sex workers were infected with HIV-1 CRF01_AE. Fourteen of the 33 (42.4%) heterosexual married men with CRF01_AE had transmitted HIV-1 to their wives, whereas only 1 of 17 (5.9%) men with HIV-1 B had transmitted HIV-1 to their spouses (p < .01). Of 18 heterosexual male injecting drug users, 1 of 12 (8.5%) with HIV-1B and 5 of 6 (83.3%) with HIV-1 CRF01_AE had had sexual contact with female commercial sex workers (p < .01). Therefore, in this population, CRF01_AE was preferentially associated with heterosexual risk groups, a finding compatible with differences in transmission capability between B and non-B subtypes.

Emerging concepts in gastrointestinal aspects of HIV-1 pathogenesis and management

GASTROENTROLOGY 2001;120:607-621

Epidemiology of HIV in Estonia.

The aim of this study was to report on the epidemiology of HIV infection in Estonia and to molecularly characterize Estonian HIV-1 variants. Epidemiological data were obtained from the Estonian National HIV/AIDS Database. In 1995-1996 blood samples were collected from 54 of the 65 HIV-infected individuals that had been diagnosed at that time. The V3 domain of the env gene was directly sequenced from peripheral blood mononuclear cells of 49 of these 54 individuals and the sequences used for phylogenetic analyses. At the end of 1999 Estonia reported 96 diagnosed HIV cases; 46 (48%) were homosexual or bisexual men and 31 (32%) were presumed to have been infected heterosexually. Importantly, only four individuals were likely to have become infected through intravenous drug use. Forty-three individuals (45%) were presumed to have been infected outside of Estonia, whereas 38 (40%) were likely to have become infected in Estonia. As expected, a majority of the investigated individuals (80%) were found to carry subtype B virus. Infections with subtypes A, C, D, G, and CRF02_AG were also documented. The dominance of subtype B was restricted to homosexual and bisexual men. Thus, subtype B infections were documented in 33 of 34 (97%) homosexual and bisexual men, but only 6 of 15 (40%) individuals with other probable routes of infection. Thirty of the 39 subtype B sequences were joined in a tight sequence cluster that also included sequences from neighboring Russia and Lithuania. This pattern suggests a local spread of HIV-1 among homosexual and bisexual men within the region. The results from the phylogenetic analyses agreed well with other epidemiological information. In conclusion, Estonia remains a country with a low prevalence of HIV infection. A majority of the identified cases are homosexual or bisexual men, whereas HIV infection among intravenous drug users is rare. A large proportion of the homosexual and bisexual men carried closely related subtype B variants. The sequences have been deposited in GenBank under accession numbers AF286538-AF286586.