Interplay Between Geography and HIV Transmission Clusters in Los Angeles County.

BACKGROUND: Clusters of HIV diagnoses in time and space and clusters of genetically linked cases can both serve as alerts for directing prevention and treatment activities. We assessed the interplay between geography and transmission across the Los Angeles County (LAC) HIV genetic transmission network. METHODS: Deidentified surveillance data reported for 8186 people with HIV residing in LAC from 2010 through 2016 were used to construct a transmission network using HIV-TRACE. We explored geographic assortativity, the tendency for people to link within the same geographic region; concordant time-space pairs, the proportion of genetically linked pairs from the same geographic region and diagnosis year; and Jaccard coefficient, the overlap between geographical and genetic clusters. RESULTS: Geography was assortative in the genetic transmission network but less so than either race/ethnicity or transmission risk. Only 18% of individuals were diagnosed in the same year and location as a genetically linked partner. Jaccard analysis revealed that cis-men and younger age at diagnosis had more overlap between genetic clusters and geography; the inverse association was observed for trans-women and Blacks/African Americans. CONCLUSIONS: Within an urban setting with endemic HIV, genetic clustering may serve as a better indicator than time-space clustering to understand HIV transmission patterns and guide public health action.

HIV knowledge and its correlation with the Undetectable = Untransmittable slogan in Brazil

ABSTRACT Knowledge about HIV transmission and prevention is a necessary step for adopting preventive behaviors. We assessed HIV knowledge and its correlation with the perceived accuracy of the "Undetectable = Untransmittable" (U=U) slogan in an online sample with 401 adult Brazilians. Overall, 28% of participants showed high HIV knowledge level. The perceived accuracy of the U=U slogan significantly correlated with HIV knowledge. Younger participants, those reporting lower income or lower education, or who had never tested for HIV showed poorer HIV knowledge. Filling gaps of knowledge among specific populations is urgent in order to increase preventive behaviors and decrease HIV stigma.

Parenteral transmission of HIV in Africa.

PIP: HIV is known to be transmitted sexually, perinatally, and parenterally. Parenteral transmission is defined as that which occurs outside of the alimentary tract, such as in subcutaneous, intravenous, intramuscular, and intrasternal injections. The relative percentage of HIV infection caused by each of these routes depends upon the prevalence of infection among particular groups of the population and on their shared behaviors. Although heterosexual transmission is the primary mode of HIV infection in Africa, health care providers and traditional healers both in and out of the health care setting in Africa administer a large number of injections. As such, parenteral transmission could be contributing significantly to HIV infection in the region. This paper reviews what is known about the parenteral transmission of HIV in Africa. The biology of parenteral transmission in blood and in interstitial fluid is described, then sections follow on HIV transmission by injection, occupational transmission, transmission by scarification, and transmission by immunization. Available data suggest that while HIV may be occasionally transmitted in Africa through injections, it is most likely not a major route of infection in the region. Sterilizing needles and syringes, and using injections as last resort therapy will greatly reduce the risk of parenteral HIV transmission.^ieng

The relationship between male circumcision and HIV infection in African populations.

The relationship between HIV seroprevalence and the proportion of uncircumcised males in African countries is examined to determine whether circumcision practices play a role in explaining the large existing variation in the sizes of African HIV epidemics. A review of the anthropological literature yielded estimates of circumcision practices for 409 African ethnic groups from which corresponding national estimates were derived. HIV seroprevalence rates in the capital cities were used as indicators of the relative level of HIV infection of countries. The correlation between these two variables in 37 African countries was high (R = 0.9; P less than 0.001). This finding is consistent with existing clinic-based studies that indicate a lower risk of HIV infection among circumcised males.

PIP: Wide variations in the HIV epidemic exist among the different countries in Africa. The relationship between HIV seroprevalence and the proportion of uncircumcised males is examined to determine whether circumcision practices play a role in explaining the variation in the sizes of the African HIV epidemics. Circumcision practices for 409 African ethnic groups were corresponded with national estimates of HIV infection levels. Although age at circumcision and other ethnic group identity characteristics were known, this information was not considered in this study. HIV seroprevalence rates in the capital cities were used to indicate the relative level of HIV infection in the countries. In 5 countries where more than 3 quarters of males were estimated to be uncircumcised, the average HIV prevalence was 16.4%. In none of the capital cities of these 5 countries was the seroprevalence less than 9.5%. Among the 20 countries where more than 90% of males were circumcised, the average seroprevalence was 0.9% and in no case did it exceed 4%. The correlation between these 2 variables was high (R=0.9%;P 0.001). Although strong population level correlation between circumcision and HIV seroprevalence exists, it does not prove a cause and effect relationship. However, the results are consistent with existing clinic-based studies that indicate a lower risk of HIV infection among circumcised males and suggest that male circumcision is a cofactor in HIV infection.

The molecular epidemiology of HIV in Asia.

PIP: The human immunodeficiency virus (HIV) was introduced readily into Asia and has quickly spread between Asian states through both parenteral and sexual modes of transmission. Only 1 year after Thailand's epidemic wave among intravenous drug users (IDUs) in 1988, the virus spread to the adjacent Myanmar and Malaysia, and another year later IDUs were infected in parts of India and China bordering Myanmar. Several methods can be used to quantify the genetic diversity, divergence, or variation within or between subtypes, genotypes, or isolates. Consensus sequences, representing the most common nucleotide in the genome, are often generated for comparison. 8 subtypes A through F, H, and O have been described for HIV-1 based on the genetic similarities and differences in the env gene or viral envelope. Subtype A and D have been found primarily in central and western Africa. Subtype B is predominant in Europe, the Western hemisphere, Japan, and Australia. Subtype C has been found mostly in southern Africa, the Central African Republic, and India. Subtype E was first identified in Thailand and recently in the Central African Republic. Subtype F has been found in Romania and is a rare variant in Brazil. Isolates from Gabon and the Russian Federation were designated subtype H. An "outlier" subtype O containing 2 human and 2 chimpanzee isolates has been identified in Cameroon and Gabon. Sequencing of the relatively conserved gag gene of geographically diverse HIV-1 isolates yielded a classification with 7 subtypes A-D and F-H. Other topics discussed include genome characterization, comparison with foreign isolates, segregation by mode of transmission, and biologic properties of HIV-1 variants in Thailand; regional diversity of HIV-1 subtypes and substantial spread of HIV-2 in India; as well as HIV transmission and infections in Japan, Australia, Cambodia, China, Taiwan, Philippines, Malaysia, Myanmar, and in states created out of the former Soviet Union.^ieng

Epidemiology of HIV infection and AIDS: incubation and infectious periods, survival and vertical transmission.

PIP: Recent research on the natural history of HIV infections and AIDS, specifically the incubation period of AIDS, infectiousness during this period, efficiency of vertical transmission and survival of AIDS patients is summarized. The AIDS incubation period is the duration of time from initial infection with HIV to development of symptoms of the disease. Timing of diagnosis varies depending on the criteria used and their interpretation in different studies. Seroconversion times lie between 40-60 days, with wide variability. The length of the early incubation period does not differ in groups of transfusion cases (hemophiliacs) and homosexuals, but are definitely shorter in perinatally infected infants (1 year). The mean incubation period in transfusion cases is 7.66 years. Theoretically, infectiousness peaks just after infection, and then later when the patient progresses to AIDS-related complex and to AIDS. There is some evidence, besides high levels of HIV antigen levels, to support this view. Perinatal, also called vertical, transmission of HIV is also more efficient when the mother exhibits AIDS symptoms. Survival times of AIDS patients averages 9-13 months. The type of disease symptoms influences survival, with those presenting with Kaposi's sarcoma showing longer survival. The percentage of longterm adult survivors, ( 4 years) is low, 2-5%. Perinatally infected infants survive only 8-9 months.^ieng

The importance of core groups in the epidemiology and control of HIV-1 infection.

PIP: In Africa, HIV transmission occurs mainly through heterosexual intercourse. High-frequency transmitter core groups are key to the epidemiology of HIV-1 and STD on the continent. The rapid growth of the HIV-1 epidemic in Africa appears to have resulted, in part, from social and economic factors which result in individuals' frequent engagement in sexual intercourse with members of HIV-infected core groups. Understanding the importance of core groups in HIV-1 transmission is therefore key to developing more effective programs for the control of HIV-1. Sections explore the core groups concept and the sexual transmission of infection, social and economic forces creating core groups in Africa, the interaction of STD and HIV-1 in core groups, the effect of STD on HIV-1 disease progression in core groups in accelerating the HIV-1 epidemic, the role of core group interventions in control programs, balancing disease control with the potential for victimization, and research needs.^ieng

Injecting drug use and HIV infection in southwest China.

OBJECTIVES: To determine the prevalence of drug injection among drug users, the seroprevalence of HIV and risk factors for HIV infection among injecting drug users (IDU), and to determine heterosexual transmission of HIV among IDU and their spouses in southwest China. METHODS: Using a cross-sectional design, we conducted an HIV seroprevalence and behavioral survey in three rural counties of Yunnan province, Ruili, Longchuan and Luxi in southwest China, bordering Myanmar (Burma). A total of 860 drug users were recruited in randomly selected communities at the three study sites (response rate, 97%). In addition, a random sample of 62 wives of HIV-infected IDU were assembled from 460 known HIV-positive IDU in Ruili and Longchuan (response rate, 81%). RESULTS: In the sample of 860 drug users, 33% reported injecting drugs. Among the 282 subjects who injected drugs, 82% began intravenous drug use after 1988; 64% injected drugs at least once every day. All subjects shared needles but none cleaned the injection equipment with alcohol or bleach. Overall, 49% tested HIV-positive. HIV seropositivity was independently correlated with a longer history of drug injecting, daily injecting, frequent needle-sharing, being younger, and living in Ruili county. Among the 62 wives of HIV-positive IDU, none used condoms during sex and 10% tested HIV-positive. CONCLUSIONS: We conclude that the introduction of HIV into drug-using communities and the rapid increase in heroin injecting in this population appear to have triggered an explosive HIV epidemic among IDU in southwest China. We recommend that AIDS prevention efforts should begin immediately and focus on discouraging the shift from opium smoking to heroin injecting, needle-sharing, and unprotected sex among drug users and their partners.

PIP: The authors investigated the prevalence of drug injection among drug users, the seroprevalence of HIV and risk factors for HIV infection among injecting drug users (IVDUs), and the extent of heterosexual transmission of HIV among IVDUs and their spouses in southwest China. Findings are based upon a cross-sectional HIV seroprevalence and behavioral survey in the rural counties Ruili, Longchuan, and Luxi of Yunnan province in southwest China. 860 drug users were recruited in randomly selected communities along with a random sample of 62 wives of HIV-infected IVDUs. 33% of the 860 drug users reported injecting drugs. Of the 282 who injected drugs, 82% began IV drug use after 1988, and 64% injected drugs at least once daily. All subjects shared needles, but none cleaned the injection equipment with alcohol or bleach. 49% overall tested HIV-seropositive. HIV seropositivity was independently correlated with a longer history of drug injecting, daily injecting, frequent needle-sharing, being younger, and living in Ruili county. None of the 62 wives of HIV-positive IVDUs used condoms during sex and 10% tested HIV-positive. The introduction of HIV into drug-using communities and the rapid increase in heroin injecting in the population appear to have triggered an explosive HIV epidemic among IVDUs in the region. It is recommended that AIDS prevention efforts begin immediately with a focus upon discouraging the shift from opium smoking to heroin injecting, needle-sharing, and unprotected sex among drug users and their partners.

Reasons for the wide variation in reported rates of mother-to-child transmission of HIV-1.

PIP: The explanation of marked global variation (between 12 and 65%) in the rate of mother-to-child transmission (MCT) of HIV-1 both in developed and developing countries is inadequate. The risk of MCT ranges from one in eight to one in 1.5 pregnancies. There are marked methodological differences in the case definitions, study designs and diagnostic criteria in the various MCT investigations. Although most HIV-1 MCT appears to occur in the peripartum period, it can also occur in the intrauterine phase or immediately postpartum requiring diagnostic techniques that are not often available. Polymerase chain reaction or in situ hybridization tests for early diagnosis of MCT have been found to lack specificity for both HIV-infected and uninfected infants who are born to HIV-infected mothers and who remain HIV-seropositive during their first year of life. A second explanation for the wide variability derives from the varying case mix of any given maternal cohort. HIV infection during pregnancy and pregnant women with advanced HIV-induced immunosuppression are particularly infectious to their children. A third source of MCT variation results from selection bias in many MCT studies. It is not known whether the only mechanism of transmission in the perinatal period is transplacental or transmission occurs during delivery. Data suggest that delivery via Caesarean section halves the risk of MCT. Antiretroviral treatment (zidovudine) for HIV-infected mothers in the immediate prepartum and intrapartum period, followed by postpartum administration to their infants has reduced these infants' chance of MCT by as much as 50%. A recent study from Malawi demonstrated that HIV-1-seropositive women with vitamin A deficiency had a twofold greater risk of transmitting HIV-1 infection to their infants. The many biologic reasons for the wide variation in MCT make it unlikely that prevention will be possible through a single biologic and/or pharmacologic approach.^ieng

Lessons from the second AIDS virus, HIV-2.

PIP: Although the clinical signs and symptoms of human immunodeficiency virus (HIV)-2 are similar to those associated with HIV-1 infection, the former virus has a markedly lower perinatal transmission rate and heterosexual infectivity potential. An ongoing cohort study in Senegal, where the disease was first encountered a decade ago, of 136 HIV-2-infected women found an overall incidence of acquired immunodeficiency syndrome of only 0.18/100 person-years in 548 person-years of observation. Moreover, the rate of developing an abnormal CD4 lymphocyte count from the time of infection onward was 1%/year for HIV-2 infected women compared to 10% for HIV-1. In vitro studies of HIV-2 have shown reduced cell killing, less syncytia formation, and slower viral replication compared to HIV-1. It remains unclear whether viral features alone account for the long clinical latency period and different transmission dynamics of HIV-2. An interesting early finding of the Senegalese study is that partial protection from HIV-1 exists in those already infected with HIV-2. Further delineation of the mechanisms involved in this seeming protective effect should be a high research priority given the potential for prevention of the more virulent HIV-1 strain.^ieng

Evaluation of mechanical transmission of HIV by the African soft tick, Ornithodoros moubata.

OBJECTIVES: To assess the ability of the African Hut Tampan, Ornithodoros moubata, to mechanically transmit HIV-1 and to re-appraise HIV-1 infectivity in an arthropod cell line at 28 and 35 degrees C. DESIGN: To evaluate HIV-1 transmission by O. moubata, as determined by HIV-1 survival, 'blood-meal' size and interval between feeds, various tick developmental stages were allowed to feed on a heavily infected lymphoblast-rich blood-meal containing HIV-1BRU in an in vitro feeding chamber. METHODS: Blood-meal regurgitation was evaluated using 51Cr-labelled human erythrocytes, and human lymphoblast survival in ticks using Trypan blue. HIV-1 survival in ticks was evaluated by reverse transcriptase activity in tick homogenates cocultured with CEM lymphoblasts. Polymerase chain reaction and Southern blot analysis were used to detect proviral HIV-1 in arthropod cells in vitro. RESULTS: HIV-1BRU remained viable for up to 10 days with O. moubata adults. This is the longest recorded survival of HIV in an arthropod. In agreement with other studies. O. moubata regurgitated part of its previous blood-meal into the feeding lesion. Human CEM lymphoblasts partially survived for up to 7 days at 28 and 35 degrees C inside O. moubata's digestive tract. The blood-meal of adult female ticks was as high as 240 microliters (approximately 70 times more than a mosquito), while the most likely potential mechanical vectors (fourth- and fifth-stage nymphs) ingested an average of 39 microliters (maximum, 73 microliters), with some ticks re-feeding as early as 14 days postfeed in the absence of a moult. Shortcomings associated with the experimental protocol suggest that HIV survival within O. moubata may reach 14 days following natural infection, or that ticks might re-feed earlier. Although HIV-1BRU and HIV-1NDK were unable to replicate at 28 and 35 degrees C in CD4- Aedes albopictus C6/36 mosquito cells, HIV-1NDK was detected in its proviral form. CONCLUSIONS: Our investigations showed that mechanical transmission of HIV-1 by O. moubata is unlikely to occur in the laboratory. This may not be the situation under field conditions.

PIP: In an in vitro feeding chamber, African Hut Tampan ticks (Ornithodoros moubata) fed on CEM lymphoblast-rich human blood containing a copious amount of HIV-1 BRU so that the ability of the tick to transmit HIV-1 at 28 and 35 degrees Celsius--ambient temperatures in some parts of Africa--could be examined. The authors also used Aedes albopictus mosquito cells and HIV-1 BRU and HIV-1 NDK to reexamine HIV-1 infectivity in an arthropod cell line at 28 and 35 degrees Celsius. Some adult female ticks ingested as much as 240 mcl of blood, about 70 times the amount ingested by mosquitoes (mean, 106.3 mcl). On the other hand, the fourth and fifth stage nymphs which are the most likely mechanical vectors of HIV consumed a mean of 39 mcl (maximum, 73 mcl). The shortest interval between feeds for nymphs which had not yet molted was 14 days. But other studies suggested that ticks often refeed sooner than 14 days. The ticks regurgitated part of their previous blood meal into the feeding lesion when they later fed on a suckling mouse. Adult ticks harbored viable HIV-1 BRU for as long as 10 days, the longest recorded survival of HIV in an arthropod. Yet, other evidence indicated that HIV survival in O. moubata under natural conditions could actually be 14 days. 4.5% and 1.3% of human CEM lymphoblasts remained viable up to 7 days in the ticks' digestive tract at 28 and 35 degrees Celsius, respectively. Neither HIV-1 BRU nor HIV-1 NDK could replicate in CD4-A. albopictus C6/36 mosquito cells, but the authors did find some evidence of retrotranscription of HIV-1 is probably not possible in vitro, but it could contribute somewhat to HIV-1 transmission in areas of Central Africa where HIV prevalence is high.

The effectiveness of condom use in heterosexual prostitution in The Netherlands.

OBJECTIVES: To assess the extent to which condoms are used effectively in commercial heterosexual intercourse. Data on the number of condoms that had broken or slipped off, the sexual technique during which this had occurred and the perceived cause of failure were collected. The use of non-water-soluble lubricants and non-fortified condoms during anal intercourse, and the demand for a greater variety of condom sizes were also examined. SUBJECTS AND METHODS: One hundred and twenty-seven female prostitutes and 91 male clients from different parts of The Netherlands were interviewed face-to-face between July 1990 and March 1991. RESULTS: Of those who used condoms during vaginal intercourse, 49% of the prostitutes had experienced condom breakage in the previous 6 months, and 16% of the clients in the previous 12 months. The breakage rate was 0.8% for prostitutes and 1.5% for clients. Condom quality was seldom reported as the cause; breakage was generally attributed to human factors, such as rough or prolonged intercourse, incorrect handling of the condom or the use of insufficient lubricant. Prostitutes also identified penis size as a cause. Condoms slipping off before or after ejaculation was reported less frequently than breakage. Thirteen per cent of clients and 36% of prostitutes expressed a need for either smaller or larger condoms. Of the prostitutes, 9% used oil or vaseline as a lubricant. CONCLUSIONS: In view of the low rate of condom failure in heterosexual prostitution in The Netherlands, the potential spread of HIV by this means is small. The use of a greater variety of condom sizes may further reduce the failure rate. Few prostitutes remain ignorant about the adverse effects of oil-based lubricants on condoms.

Prostitution and HIV: what do we know and where might research be targeted in the future?

PIP: A review of the literature indicates that the association between human immunodeficiency virus (HIV) and prostitution varies by geographic region and can be altered substantially by well-planned public health interventions. In most African countries and in Asian countries such as Thailand, the rate of HIV infection among female prostitutes is substantially higher than the rate in the general population. Relatively few commercial sex workers in South and Central America are HIV-positive; however, their extremely high rates of infection with sexually transmitted diseases indicates the potential for future epidemic spread of HIV. In Europe and North America, HIV infection is most prevalent among drug-injecting or crack-using prostitutes. Neglected has been research on the high incidence of HIV among male transvestite and transsexual prostitutes. The lowest levels of condom use in commercial sex encounters have been recorded in regions in developing countries with the highest HIV prevalence. Also of concern are high condom breakage rates (20-50%) among female prostitutes who use petroleum-based lubricants and male prostitutes who practice anal sex. Valuable would be quantification of the additional HIV risk resulting from sex with a prostitute. Other recommended research areas include estimates of the number of male and female prostitutes working in certain geographic areas, mechanisms for monitoring condom use and substance abuse among prostitutes, the impact of HIV infection on movement into and out of prostitution, the dynamics of prostitute-client condom negotiation, and profiles of the clients of male prostitutes.^ieng

Acute HIV illness following blood transfusion in three African children.

Three children are described in whom pre-transfusion samples were HIV-seronegative and post-transfusional samples, obtained within 1 week after transfusion, were HIV-seropositive. Two of them developed a transient fever within 1 week of receiving the blood transfusion, and a transient generalized skin eruption which lasted for about 2 weeks. All three developed persistent generalized lymphadenopathy. One child developed a lumbar herpes zoster 7 months after transfusion. IgM Western blots demonstrated the presence of antibodies to protein bands p17, p24 and p55 in all three children. These three case reports suggest that children who receive a seropositive blood transfusion are at high risk for developing acute manifestations of HIV infection.

The impact of HIV-1 infection on child survival in the developing world.

In this study we have used a mathematical projections model and HIV-1 seroprevalence data from samples of pregnant women to estimate infant HIV-1-infection prevalence and HIV-1-attributable mortality among children. This paper presents the results of samples from six developing country capitals and Martinique. The estimated impact of HIV-1 infection on overall infant mortality is low in regions where maternal HIV-1 seroprevalence is low and overall infant mortality is high, but substantial in locations where either maternal HIV-1 seroprevalence is high, or where maternal HIV-1 seroprevalence is moderate and overall infant mortality is low. The estimates for child (ages 1-4 years) and under-5 mortality suggest that the impact of HIV-1 infection on overall mortality in children may exceed the impact on infant mortality. The recent gains made in ensuring child survival are likely to be increasingly reversed in regions where HIV-1 infection is being transmitted in a substantial proportion of pregnancies and births.

PIP: A mathematical projections model was applied to human immunodeficiency virus (HIV)-1 data from samples of pregnant women in 6 capital cities in sub-Saharan Africa and the Caribbean as well as Martinique in order to estimate HIV-1 prevalence and HIV-attributable child mortality. Aside from Martinique, which was selected as a control, the 6 capital city samples were all from developing countries with high overall levels of infant and child mortality and low gross national products. The infant HIV-1 infection prevalence was arrived at by multiplying maternal seroprevalence rates in the capital city sample by current estimates of the vertical transmission rate (currently set at 24-39%). This methodology resulted in the following estimated percentages of infant HIV-1 infection prevalence: Martinique, 0.0.4%; Mozambique, 0.0-0.3%; Ivory Coast, 0.2-2%; Zaire, 1.8-3.5%; Haiti, 1.7-3.8%; Zambia, 2.5-5.0%; and Uganda, 4.5-11.5%. These prevalences were then multiplied by the probability of an HIV-infected liveborn dying at under 1 year and under 5 years of age. The estimates of under-5 years HIV-1-attributable mortality were as follows: Martinique, 1-3/1000 live births; MOZAMBIQUE, 0-2/1000; Ivory Coast, 1-17/1000; Zaire, 7-28/1000; Haiti, 7-30/1000; Zambia, 10-40/1000; and Uganda, 18-89/1000. In developing countries with low HIV-1 seroprevalence, children are at greatest risk of death in the 1st year of life. However, the estimates obtained in this study suggest that the impact of HIV-1 infection on child mortality may exceed the impact on infant mortality in regions with high rates of HIV-1 infection and undermine any gains that have been made in the area of child survival.

Non-isotopic polymerase chain reaction methods for the detection of HIV-1 in Ugandan mothers and infants.

Two non-isotopic polymerase chain reaction (PCR) methods were evaluated by testing blood from 41 HIV-1-seropositive and 16 HIV-1-seronegative Ugandan mothers and 56 of their children (aged 0.5-15.0 months). Amplification of HIV-1 sequences was performed in duplicate using a biotinylated primer pair to the gag region (SK 462-431) and nested primer pairs (JA 17-20) to the pol region of HIV-1. gag sequences were hybridized using a microtiter plate coated with the SK 102 probe followed by colorimetric detection using an avidin-horseradish peroxidase conjugate and tetramethylbenzidine/peroxide substrate. pol sequences were detected on agarose gel stained with ethidium bromide. Results of HIV-1 PCR analysis showed that 40 out of 41 (98%) seropositive mothers and 10 out of 29 (34%) seropositive children had detectable HIV-1 gag and pol sequences. None of the 16 seronegative mothers nor 27 seronegative or Western blot-indeterminate children had detectable HIV-1 sequences. Our results suggest that non-isotopic PCR methods are sensitive, specific, and potentially useful in the early diagnosis of HIV-1 infection in developed and developing countries.

Risk factors and HIV seropositivity among injecting drug users in Bangkok.

Bangkok experienced an extremely rapid spread of HIV infection among drug injectors in 1987 and 1988. This study examines risk factors for HIV infection and deliberate risk-reduction efforts by drug injectors. Two subsamples of injecting drug users were recruited in November 1989, a group in drug-use treatment (n = 342) and a group new to the treatment system (n = 259). Subjects were interviewed about AIDS risk behavior, and a blood sample was collected for HIV testing. Seroprevalence was 39 and 27% in the in-treatment sample and the new-to-treatment sample, respectively. The in-treatment sample seroprevalence rate is similar to rates observed 6 and 12 months earlier. Three factors were independently associated with HIV infection: subsample, having been in prison, and sharing injection equipment with two or more individuals in the previous 6 months. Deliberate risk reduction was reported by 92% of individuals, with 59% reporting that they had stopped sharing injection equipment. It appears that large-scale risk reduction has greatly slowed HIV transmission among drug injectors in Bangkok.

Risk of transfusion-associated HIV transmission in Kinshasa, Zaire.

Between 5 March and 12 April 1990, we assessed transfusion practices and the risk of transfusion-associated HIV transmission in all the hospitals and medical centres in Kinshasa, Zaire. Of the 733 hospitals and medical centres surveyed, 62 (8.5%) transfuse blood. Of 3741 units of blood transfused in February 1990, 1045 (27.9%) were not screened for HIV infection. Eighteen out of 62 centres (29%) received HIV test kits on a regular basis. Twenty of the centres (32.3%) recorded HIV test results. Major blood group cross-matching was done by 9.7% (six out of 62) of the centres. Bacteriological results indicated contamination in 17% (four out of 23) of stocked blood units, 6.4% (four out of 62) of solutions for disinfections, and 22% (13 out of 59) of sterilized instruments (possessed by 59 centres only). Transfusion practices in Kinshasa are associated with considerable health risks. The establishment and appropriate supervision of HIV screening facilities should be integrated into primary health-care programmes in order to increase safe transfusions in Kinshasa.

PIP: Between March 5-April 12, 1990, the authors assessed transfusion practices and the risk of transfusion-associated HIV transmission in all of the hospitals and medical centers in Kinshasa, Zaire. Of the 733 hospitals and medical centers surveyed, 62 (8.5%) transfuse blood. Of 3741 units of blood transfused in February 1990, 1045 (27.9%) were not screened for HIV infection. 18 of 62 centers (29%) received HIV test kits on a regular basis. 20 of the centers (32.3%) recorded HIV test results. Major blood group cross-matching was done by 9.7% (6 of 62) of the centers. Bacteriological results indicated contamination in 17% (4 of 23) of stocked blood units, 6.4% (4 of 62) solutions for disinfections, and 22% (13 of 59) of sterilized instruments (possessed by only 59 centers). Transfusion practices in Kinshasa are associated with considerable health risks. The establishment and appropriate supervision of HIV screening facilities should be integrated into primary healthcare programs in order to increase safe transfusions in Kinshasa.

HIV-1 infection among lower class commercial sex workers in Chiang Mai, Thailand.

OBJECTIVE: To determine risk factors for HIV-1 infection in female commercial sex workers (CSW) in northern Thailand. METHODS: A cross-sectional survey of female CSW from 11 sex establishments frequented by military conscripts that included an interview and serological testing for HIV-1. RESULTS: The HIV-1 seroprevalence in 230 CSW was 65%; the rate was lower among CSW from Chiang Mai than from rural areas. Multivariate logistic regression analysis for HIV-1 included the following significant factors: non-urban location of the sex establishment, ethnic Thai lowlander, lower price, history of genital warts and dysuria. Condom use, number of partners and duration of employment were not significantly associated with HIV-1 prevalence after adjustment for other risk factors. CONCLUSIONS: The high level of HIV-1 seroprevalence in this sample demonstrates the risk of transmission in lower cost commercial sex encounters in northern Thailand. Non-Thais (ethnic Hill tribes and Burmese) had lower HIV-1 prevalence than ethnic Thais. Type of establishment ('direct' brothel-based or 'indirect' establishments) was not predictive of HIV-1 seroprevalence. However, rural establishments were less vigilant in promoting condom use, suggesting the need for renewed efforts to enforce the Ministry of Public Health's '100% Condom Campaign' in commercial sex establishments.

The epidemiology of HIV infection among injecting drug users and other risk populations in Thailand.

PIP: HIV infection and AIDS in Thailand had been increasing among injecting drug users (IDU) from approximately 1% reported in 1987 to over 40% in late 1988. Two genetically different viruses have been shown to cause HIV infection among IDU and individuals infected sexually. HIV subtype B is responsible for 67-78% of infections in IDU patients, while HIV subtype E is responsible for 96% of infections in sexually acquired cases. It appears that 2 separate epidemics are occurring simultaneously. It has recently been noted that the HIV subtype E frequency in the IDU individuals seems to be increasing. A stable, but high, HIV prevalence rate of 40% among IDU in Bangkok was found. The incidence, however, is higher than observed in IDU individuals from Europe or North America. This is believed to be related to the high turnover rate (70%) of IDU individuals seeking the Thai government's detoxification treatment program. This study also compared 2 methods for estimating seroconversion. Method one assumed that the study subjects had an equal risk of HIV seroconverting on any day between blood testing (midpoint analysis) and produced an artificially low incidence estimate at both the beginning and end of a study interval. Method two assigned an equal probability for each day of the study interval for the patient to seroconvert. According to the author, this produced a more realistic estimate of the incidence curve. The IDU infections are important but are generally considered a minor part of the HIV infection epidemic which is occurring in Thailand. Thailand's HIV-positive population offers an opportunity for a field study of vaccines, as well as an opportunity to field test and evaluate prevention methods and strategies.^ieng