Confidence intervals for biomarker-based human immunodeficiency virus incidence estimates and differences using prevalent data

Prevalent biologic specimens can be used to estimate human immunodeficiency virus (HIV) incidence using a two-stage immunologic testing algorithm that hinges on the average time, T, between testing HIV-positive on highly sensitive enzyme immunoassays and testing HIV-positive on less sensitive enzyme immunoassays. Common approaches to confidence interval (CI) estimation for this incidence measure have included 1) ignoring the random error in T or 2) employing a Bonferroni adjustment of the box method. The authors present alternative Monte Carlo-based CIs for this incidence measure, as well as CIs for the biomarker-based incidence difference; standard approaches to CIs are typically appropriate for the incidence ratio. Using American Red Cross blood donor data as an example, the authors found that ignoring the random error in T provides a 95% CI for incidence as much as 0.26 times the width of the Monte Carlo CI, while the Bonferroni-box method provides a 95% CI as much as 1.57 times the width of the Monte Carlo CI. Further research is needed to understand under what circumstances the proposed Monte Carlo methods fail to provide valid CIs. The Monte Carlo-based CI may be preferable to competing methods because of the ease of extension to the incidence difference or to exploration of departures from assumptions.

Needlestick injury and human immunodeficiency virus (HIV): a surgeon's personal story

With increasing numbers of HIV positive patients worldwide, the oculoplastic surgeon will come into greater contact with them. This increases the chances of accidental occupational exposure and the risk of self-inoculation with HIV. This presentation describes an oculoplastic surgeon's personal experience with a needle stick injury in a known HIV positive patient. The surgeon must be fully educated as to the "2-hour window" after the injury in which the decision must be made with respect to post-exposure anti-retroviral prophylaxis, and initiation of treatment in an attempt to prevent seroconversion. This presentation also outlines the important medical and legal issues of informed consent, ramifications of seroconversion, and the important issues of antiretroviral drug toxicity and compliance. The surgeon will describe the success of the post-exposure prophylaxis regimen in preventing seroconversion for the prescribed six-month follow-up period, and will discuss the tremendous anxiety until the final negative test result was available (AU)

Drug use and syphilis: co-factors for HIV transmission among commercial sex workers in Guyana

A cross-sectional survey was conducted among 124 street-and brothel-based female commercial sex workers (CSWs) in Georgetown in January and February 1997 to determine the seroprevalence of human immunodeficiency virus (HIV) infection and describe the sexual practices and drug use patterns. Their median age was 30 years (range 17 to 52 years). 119 (88 percent) reported regular alcohol consumption while looking for clients, 27 (22 percent) said they smoked cocaine and 51 (42 percent) reported use of marijuana. Street-based CSWs were significantly more likely to report marijuana use (p = 0.033). 72 percent reported that they never used condoms with regular sex partners and 35 percent reported that they never used condoms with clients. Brothel-based women were significantly more likely to report consistent condom use with their clients (p = 0.05). 46 percent (54/118) tested HIV positive and 28 percent (33/118) had a positive serological test for syphilis. Factors that were significantly associated with HIV infection included a positive serological test for syphilis (OR = 7.56; 95 percent CI = 2.7-21.97; p < 0.01) and a history of having received treatment for syphilis (OR = 2.93; 95 percent CI = 1.12-7.8). Weak associations were also found between HIV infection and a history of cocaine use (OR = 2.57; 95 percent CI = 0.95-7.11; p = 0.039); having more than four clients per night (OR = 5.14; 95 percent CI = 1.65-16.74; p = 0.04; and a history of receiving treatment for salpingitis (OR = 2.31; 95 percent CI = 0.93-5.75; p = 0.0035). No statistically significant association was found between HIV infection and marijuana use nor any sociodemographic variables (age, place of work, and duration of sex work). There is an urgent need for a community based behavioural intervention programme targetting this high risk population (AU)

Improving community care for persons with the acquired immunodeficiency syndrome in Jamaica

A brief review of the HIV/AIDS epidemic in Jamaica is presented along with the details of a pilot programme aimed at training lay persons and practical nurses to assist with home care of persons with AIDS. Current (1997) estimates are that 2 to 4/1,000 Jamaican adults are HIV positive. 2,301 AIDS cases have been reported to the Epidemiology Unit of the Ministry of Health, 55 percent of whom have died. Males represent 62 percent of reported cases (1421) and children < 9 years old, 7 percent (170 cases). In 1981 a Family Centre was started at the University Hospital of the West Indies to provide support to persons with AIDS and their families. This initiative identified the need to provide special training to persons who would be responsible for caring the AIDS patient at home, where most patient preferred to be managed. All but three of the 41 persons trained in the pilot programme achieved the required standards of attendance and proficiency. Certificates valid for two years were issued and refresher courses will follow.(AU)

HIV seropositivity and associated factors among female commercial sex workers in Guyana

To determine the prevalence of, and risk factors for, HIV infection among female commercial sex workers in Guyana a cross sectional survey was done among 124 streetwalkers and brothel based female sex workers in Georgetown during January and February, 1997. The mean age was 30.6 years (range = 17 to 52; sd = 7.24). Sixty-one percent said they had worked in the sex industry for 1 to 4 years while 30 percent indicated they had worked for >4 years. Forty-six percent (54/118) tested HIV positive while 28 percent (33/118) had a positive serological test for syphilis. Factors that were significantly associated with HIV infection included a positive serological test for syphilis (OR = 7.56; 95 percent CI = 2.7 - 21.97, p<0.01), a history of cocaine use (OR = 2.57, 95 percent CI = 0.95 - 7.11, p = 0.039), having > 4 clients per night (OR = 5.14, 95 percent CI = 1.65 - 16.74, p = 0.04), a history of having received treatment for syphilis (OR = 2.93, 95 percent CI = 1.12 - 7.8, p = 0.0035) and a history of receiving treatment for salpingitis (OR = 2.31, 95 percent CI = 0.93. 95 percent CI = 1.12 - 7.8, p = 0.0035) and a history of receiving treatment for salpingitis (OR = 2.31, 95 percent CI = 0.93 - 5.75, p = 0.0035). These results show a high prevalence of HIV infection and inconsistent condom use among the participants of the study. Exposure to syphilis seems to be a major risk factor for HIV. There is an urgent need for an integrated and innovative internvention targeting this high risk population. (AU)

HIV risk perception, risk behavior, and seroprevalence among female commercial sex workers in Georgetown, Guyana

A study of 108 female sex workers engaged in prostitution in Georgetown, Guyana, was made in April 1993. Based on interviews and procurement of blood samples, the study investigated relationships between HIV seroprevalences and AIDS knowledge, risk behaviors, client characteristics, and condom use. Street-walkers-as distinct from sex workers in bars, hotels, and Port Georgetown-tended to charge less, be worse off socioeconomically, and have clients who were similiarly disadvantaged; they were therefore classified as belonging to a "lower" socioeconomic stratum, while the other workers were classified as belonging to a "higher" stratum. The overall HIV seroprevalence found among the sex workers was 25 percent (95 percent CI: 17 percent-33 percent). But the 50 subjects in the lower stratum had a relatively high seroprevalence (42 percent, as compared to 10 percent among those in higher stratum), accounting for 21 of the 27 HIV-seropositive subjects. Reported patterns of client origins (Guyanese or foreign), worker willingness to have sex without a condom, and condom use by clients differed by stratum. Participants in the higher stratum were more disposed to having sex without a condom. The workers' knowledge of what causes AIDS and how HIV is transmitted was low in both strata; substantial numbers of workers of workers said they had contracted a sexually transmitted disease within the past two years or were users of illicit drugs. Condom use is reportedly less common among Guyanese than foreign clients, suggesting a greater risk of contracting HIV from Guyanese clients or infecting Guyanese clients with it. The HIV seroprevalence among workers who said they had only Guyanese clients was statistically greater than the rate among those who said they had only foreign clients. The HIV seroprevalence among those reporting more than five clients per week was statistically greater than among those reporting fewer. HIV seropisitivity was relatively high among the 12 workers who said they used cocaine. Overall, the findings supported the view that interventions targeted at female sex workers and their clients should be strengthened-more specifically, that concerted efforts should be made to intensify condom promotion, distribution, and social marketing; to improve STD services that provide treatment and counseling for female sex workers; and to increase educational activities among the workers' Guyanese clients (AU)

Clinical manifestations of HTLV-1 infection

Adult T-cell leukaemia/lymphoma (ATL) and tropical spastic paraparesis/HTLV-1 associated myelopathy (STSP/HAM) are the major clinical manifestations of HTLV-1 infection in adults. Susceptibility is related not only to the mode and age of acquisition of the virus but also to genetic, socio-economic and geographic factors. Recently there has been documentation of a number of other disease associations in adults including: polymyositis, uveitis, arthropathy, cystitis and prostatitis. These diseases which exhibit an autoimmune mode of pathogenesis underscore the widespread systemic effects of the virus. In childhood infective dermatitis is a specific marker for HTLV-1 infection with a risk of evolution into either ATL or TSP/HAM in adult life (AU)

Occupational percutaneous exposure to human immunodeficiency virus (HIV); a decision analysis from a Caribbean perspective - abstract

A decision analysis was conducted to examine whether short-term (42 days) zidovudine should be recommended for Caribbean health care workers (HCWs), following percutaneous exposure to blood, as well as to determine the value of testing "donor" (patient's) blood. The results were compared with a similar analysis based on a North American model. The options analyzed were "TREAT ALL", "TREAT NONE"; and "TEST". In the "TREAT ALL" option, all HWCs receive short-term zidovudine immediately after exposure, "TREAT NONE" option no one receives zidovudine and in the "TEST" option, "donor" blood is tested, and if HIV-positive, zidovudine is given. Each outcome was expressed as a utility; this is a method of quantifying the values that individuals place on health states. The results showed that the "TEST" option is preferred. The value of testing "donor" blood is derived from the fact that the vast majority of HCWs would be reassured by a negative test. Sensitivity analyses indicated that even if the risk of seroconversion or the effectiveness of zidovudine is zero, this option is preferred; thus confirming the above value of testing, rather than merely identifying HCWs who should receive zidovudine. If HIV-seropositivity exceeds 42 per cent, the "TREAT NONE" option is preferred. This was found to be due to the fact that increased numbers of HCWs would be told that they were exposed to HIV-positive blood. The "worrying factor" associated with such an exposure is such that above 42 per cent HIV seropositivity, the "TREAT NONE" option is preferred. In summary, the real value of testing "donor" blood is in identifying those persons who could be told that they were exposed to HIV-negative blood; that is reducing their "worry factor" to zero. If the risk of HIV-positivity exceeds 42 per cent, in particular groups of Caribbean patients, the "TREAT NONE" option is preferred. Because AIDS is a fatal disease, and given that zidovudine is the only available prophylactic agent at present, the drug has a role to play if its effectiveness is greater than zero. In this regard, the approach should be similar to that adopted for developed countries (AU)

Update on the virology of AIDS

This article looks at the history, development, progress and research of the Human Immunodeficiency Virus (HIV) which causes AIDS. The author reports of the ongoing research into a vaccine for HIV, he examines the viral life cycle and indicates the points at which the virus can be attacked, and classifies antiviral strategies

Sexual transmission of human T-lymphotropic virus type I (HTLV-I)

Human T-lymphotropic virus type I (HTLV-I), the prototype human retrovirus, has been linked epidemilogically to adult T-cell leukemia-lymphoma and to tropical spastic paraparesis. Modes of infection include mother-to-child transmission, most likely by ingestion of breast milk; parenteral transmission by blood transfusion and intravenous drug abuse; and male-to-female sexual transmission. Female-to-male transmission of HTLV-I is thought to occur only rarely, if at all. We document risk factors for male-to-female and female-to-male transmission of HTLV-I among persons in Jamaica attending clinics for sexually transmitted disease.(AU)

Congenital human immunodeficiency virus (HIV) infection in the Bahamas

In the 13 month period between June 1985 and July 1986, 27 children were found to be HIV positive in the Princess Margaret Hospital in Nassau. Nineteen of the children had clinical AIDS, four were in the prodromal phase and four were symptom free. The clinical course of these infants is presented. Of the 18 mothers 16 were screened and were all seropositive and asymptomatic. They remained healthy in spite of subsequent pregnancies in nine of them (56 percent during a follow-up period of between 13 and 65 months (mean 40 months). Fifteen of the 18 mothers were Haitian but only three had other risk factors, throwing doubt on the valur of selective screening in Afro-Caribbean countries. (AU)

Retroviruses in the Caribbean

Transmission of HIV in many Caribbean countries has followed the pattern of initial predominance among homosexual and bisexual male, with the infection subsequently spreading into the heterosexual community. However, on Saint Lucia the epidemic began among heterosexual contacts of Saint Lucia labourers from Florida; in Bermuda 58 percent of AIDS cases have been in interavenous drug abusers; and in the infected via the perinanatal route. Seroprevalence of the human T-lymphotropic virus, type 1 (HTLV-), whose modes of transmission resemble those of HIV, has been found to range from 2.3 percent in Trinidad and Tobago to 5.4 percent in Jamaica. In a study of HIV and HTLV-1 infection patterns in homosexuals males in Trinidad and Tobago, the cohort was too small for confirmation that coinfection with these two viruses hastended progression to AIDS, but further investigation is warranted. (AU)

Epidemiology of AIDS and HIV infection in the Caribbean

A review of surveillance data on AIDS and HIV infection in the 18 English-speaking Caribbean countries and Suriname suggests that the epidemiologic pattern of AIDS in the Caribbean is evolving from an epidemic that began in 1983 among homosexual and bisexual males to one in which cases are increasingly resulting from hetrosexual contact, with different countries at various stages of transition. Overall, there has been a decline in many countries-19 percent of cases in the Bahamas are among children in Trinidad and Tobago, Jamaica, Antigua, St.Vincent and the Grenadines, and other countries show high HIV sero-prevalence among homosexuals (15-40 percent), prisoners (4-10 percent), prostitutes (up to 13 percent), and cocaine users (2 percent); at present, prevalence in general population continues to be low. (AU)

HIV and HTLV-I infection among homosexual men in Kingston, Jamaica - abstract

From August 1985 through January 1986, 123 homosexual or bisexual men from the Kingston area were enrolled in a study to determine the prevalence of human immunodeficiency virus (HIV) and the human T-lymphotrophic virus type I (HLTV-I) and the levels of risk factors for these infections. Eighteen men (15 percent) were sero-positive for HIV and 11 (9 percent) were sero-positive for HTLV-I. Only one man was positive for both viruses. The median age was 27 years (range 17 to 70). Overall, the level of promiscuity was lower than that reported in studies of homosexual men in the U.S.A. and in Europe. However, almost a third of the men reported having had homosexual encounters with foreign visitors or whilst travelling outside Jamaica. The presence of lymphadenopathy (p<0.05) was higher in HIV sero-positive patients, as was the percentage who reported having sex with men from the U.S.A. (p=0.16). Men who were sero-positive for HTLV-I tended to be more promiscuous than their sero-negative counterparts; the proportion with a history of gonorrhoea and the mean number of homosexual acts per week were both increased (p<0.05). A history of receptive anal intercourse and the mean number of homosexual partners per month were increased in positive subjects but the difference did not reach statistical significance. These results suggest that HTLV-I is an endemic, sexually transmitted infection. In contrast, HIV appears to have entered this population through homosexual contact with foreigners; the lack of association between HIV infection and promiscuity may be due to the small number of positives and the sporadic nature of transmission early in an epidemic (AU)

Progression to AIDS in homosexual men infected with HIV in Trinidad: a 3«-year follow-up - abstract

One hundred healthy homosexual or bisexual men were enrolled in a study at a venereal disease clinic in Port-of-Spain in 1983 and 40 percent were found to be HIV sero-positive as compared to 0.19 percent in a comparison group from the general population. Sexual contact with men from the USA was found to be the most significant risk factor; prior history of gonorrhoea, a marker of sexual promiscuity, was also associated with HIV sero-positivity; 15 percent were sero-positive for HTLV-I, a six-fold increase over the rate in a comparison group from the general population. The duration of homosexuality and the number of sexual partners were both associated with HTLV-I sero-positivity, suggesting that this virus, like HIV, is transmitted by homosexual activity. Six subjects were co-infected with HIV and HTLV-I; markers of altered immune status were found to be most perturbed in this group when compared with those infected with HIV alone. Prospective evaluation of the cohort has revealed that, out of 34 men who were HIV positive alone, 3 (9 percent) have progressed to AIDS in 3« years. However, of the 6 men who were co-infected, 3 (50 percent) have progressed to AIDS in the same time. Trend analysis (Kaplin and Meier) of the dates of diagnosis of AIDS among study participants (n=40) revealed a significantly increased risk of development of AIDS among individuals co-infected with HIV and HTLV-I (50 percentñ20.4 percent) as compared with those infected with HIV alone (8.8 percentñ4.9 percent). This clinical finding supports the in-vitro observation that HTLV-I infection facilitates the expression of HIV in lymphocytes infected with both retroviruses (AU)