Injuries from the wichita falls tornado: implications for prevention

We examined the circumstances of death and injury among victims of the tornado that struck Wichita Falls, Texas, on 10 April 1979. We also assessed the protective measures taken by a representative sample of community residents who suffered no major injury in order to estimate the relative risk of injury to people directly in the tornado's path. Twenty-six (60 percent) of the 43 traumatic deaths and 30 (51 percent) of the 59 serious injuries occurred in people who, despite ample warning, went to their cars to drive out of the storm's path. These people had a risk of serious or fatal injury of 23 per 1000. People who remained indoors and in stationary homes were at relatively low risk (3 per 1000) if they took simple precautions; people in mobile homes were at greatest risk (85 per 1000). Current safety recommendations and housing codes for single family homes and mobile homes need to be amended to decrease the impact of future tornadoes on human health.

Commercial sex venues: a closer look at their impact on the syphilis and HIV epidemics among men who have sex with men

OBJECTIVE

To provide insight into the role of commercial sex venues in the spread of syphilis and HIV among men who have sex with men (MSM).

STUDY

A cross sectional study of 1351 MSM who were diagnosed with early syphilis who did and did not encounter sexual partners at commercial sex venues.

RESULTS

Overall, 26% MSM diagnosed with syphilis had sexual encounters at commercial sex venues. Of these, 74% were HIV positive, 94% reported anonymous sex, and 66% did not use a condom. Compared to those who did not have a sexual encounter at these venues, they were twice as likely to be HIV positive (OR = 1.91, 95% CI 1.36 to 2.68), six times more likely to have anonymous sex (OR = 6.18, 95% CI 3.37 to 11.32), twice as likely not to use condom (OR = 2.02, 95% CI 1.71 to 2.38), and twice as likely to use non-injecting drugs (OR = 1.65, 95% CI 1.21 to 2.37).

CONCLUSIONS

MSM diagnosed with syphilis who frequent commercial sex venues are engaging in high risk behaviours for syphilis and HIV transmission and acquisition. Thus commercial sex venues are one of the focal points of syphilis and HIV transmission and acquisition.

Don't ask, don't tell: patterns of HIV disclosure among HIV positive men who have sex with men with recent STI practising high risk behaviour in Los Angeles and Seattle

OBJECTIVES

A high incidence of HIV continues among men who have sex with men (MSM) in industrialised nations and research indicates many MSM do not disclose their HIV status to sex partners. Themes as to why MSM attending sexually transmitted infection (STI) clinics in Los Angeles and Seattle do and do not disclose their HIV status are identified.

METHODS

55 HIV positive MSM (24 in Seattle, 31 in Los Angeles) reporting recent STI or unprotected anal intercourse with a serostatus negative or unknown partner from STI clinics underwent in-depth interviews about their disclosure practices that were tape recorded, transcribed verbatim, coded, and content analysed.

RESULTS

HIV disclosure themes fell into a continuum from unlikely to likely. Themes for "unlikely to disclose" were HIV is "nobody's business," being in denial, having a low viral load, fear of rejection, "it's just sex," using drugs, and sex in public places. Themes for "possible disclosure" were type of sex practised and partners asking/disclosing first. Themes for "likely to disclose" were feelings for partner, feeling responsible for partner's health, and fearing arrest. Many reported non-verbal disclosure methods. Some thought partners should ask for HIV status; many assumed if not asked then their partner must be positive.

CONCLUSIONS

HIV positive MSM's decision to disclose their HIV status to sex partners is complex, and is influenced by a sense of responsibility to partners, acceptance of being HIV positive, the perceived transmission risk, and the context and meaning of sex. Efforts to promote disclosure will need to address these complex issues.

Prevalence, incidence, and correlates of chlamydia and gonorrhea among young adult injection drug users

PURPOSE

To measure prevalence, incidence, and correlates of chlamydia and gonorrhea among injection drug users (IDUs).

METHODS

Participants (n = 2129; 63% male, 52% white, ages 18-30 years) in five US cities were tested for chlamydia and gonorrhea by urine LCR assay and completed a standardized questionnaire about demographics and recent sexual behavior. Logistic regression identified correlates of prevalent infection; incidence rates were calculated from 6-month follow-up data.

RESULTS

Chlamydia prevalence was 5.2% and did not differ by gender. Gonorrhea prevalence was 0.2% among men and 2.0% among women, P < .001. Among men, younger age [OR (95% CI): 0.89 (0.83-0.96)], age at sexual debut [0.91 (0.83-0.99)], and African American race [2.92 (1.53-5.59)] were associated with chlamydia. Among women, age at sexual debut [1.16 (1.02-1.31)] and commercial sex [1.96 (1.03-3.74)] were associated with chlamydia, and with gonorrhea [1.27 (1.04-1.56)] and [5.17 (1.66-16.11)], respectively. At 6 months, the cumulative incidence of chlamydia was 1.7% among men and 4.4% among women, P = .03; no men and 1.3% of women tested positive for gonorrhea, P = .01.

IMPLICATIONS

Prevalence and correlates of chlamydia and gonorrhea were similar to other samples, suggesting that screening criteria need not be modified for IDU populations. The number of behavioral correlates identified was limited; perhaps unmeasured sexual-network-level factors play a role in determining sexually transmitted disease (STD) prevalence.

Prevalence of HIV and hepatitis B and self-reported injection risk behavior during detention among street-recruited injection drug users in Los Angeles County, 1994-1996

AIMS

To describe injection risk behaviors while in detention in a sample of injection drug users (IDUs) in Los Angeles County.

DESIGN AND SETTING

Cross-sectional, interviewer-administered, face-to-face risk survey, and serological screening for HIV and hepatitis B conducted at four street locations in Los Angeles County between 1994 and 1996. All interviews were conducted in a non-institutionalized setting.

MEASUREMENTS

Ascertainment of self-reported risk behavior during detention and screening for HIV and hepatitis B surface antigen (HBsAg) and antibody to the core (HBcAb) seromarkers.

PARTICIPANTS

Six hundred and forty-two participants were street-recruited during the study period. Seventy-one per cent of the sample was male, the median age was 43 years, 61% were African-American, 27% were Latino, 8% were white and 36% considered themselves homeless.

FINDINGS

Overall HIV prevalence was 3.0%; 3.1% tested positive for the hepatitis B surface antigen marker (HBsAg), and 80.3% for antibody to hepatitis B core antigen (HBcAb). After adjustment for length of injection drug use and recency of release from detention, HIV seroreactivity was significantly associated with history of detention due to possession of IDU paraphernalia (OR = 1.9). The presence of the hepatitis B HBcAb seromarker was associated with injection drug use while in detention, (OR = 1.7), and having been ever arrested for possession of IDU paraphernalia (OR = 1.8).

CONCLUSIONS

IDU detainees constitute a high risk group for blood-borne infections. Comprehensive prevention and health promotion efforts in the community need to include correctional facilities.

Diagnosis of primary HIV-1 infection. Los Angeles County Primary HIV Infection Recruitment Network

BACKGROUND

The optimal approach for diagnosing primary HIV-1 infection has not been defined.

OBJECTIVE

To determine the usefulness of symptoms and virologic tests for diagnosing primary HIV-1 infection.

DESIGN

Prospective cohort study.

SETTING

A teaching hospital in Los Angeles and a university research center in San Diego, California.

PATIENTS

436 patients who had symptoms consistent with primary HIV infection.

MEASUREMENTS

Clinical information and levels of HIV antibody, HIV RNA, and p24 antigen.

RESULTS

Primary infection was diagnosed in 54 patients (12.4%). The sensitivity and specificity of the p24 antigen assay were 88.7% (95% CI, 77.0% to 95.7%) and 100% (CI, 99.3% to 100%), respectively. For the HIV RNA assay, sensitivity was 100% and specificity was 97.4% (CI, 94.9% to 98.9%). Fever, myalgia, rash, night sweats, and arthralgia occurred more frequently in patients with primary infection (P < 0.05).

CONCLUSIONS

No sign or symptom allows targeted screening for primary infection. Although assays for HIV RNA are more sensitive than those for p24 antigen in diagnosing primary infection, they are more expensive and are more likely to yield false-positive results.

Trichomonas vaginalis, HIV, and African-Americans

Trichomonas vaginalis may be emerging as one of the most important cofactors in amplifying HIV transmission, particularly in African-American communities of the United States. In a person co-infected with HIV, the pathology induced by T. vaginalis infection can increase HIV shedding. Trichomonas infection may also act to expand the portal of entry for HIV in an HIV-negative person. Studies from Africa have suggested that T. vaginalis infection may increase the rate of HIV transmission by approximately twofold. Available data indicate that T. vaginalis is highly prevalent among African-Americans in major urban centers of the United States and is often the most common sexually transmitted infection in black women. Even if T. vaginalis increases the risk of HIV transmission by a small amount, this could translate into an important amplifying effect since Trichomonas is so common. Substantial HIV transmission may be attributable to T. vaginalis in African-American communities of the United States.

Predictors of syphilis seroreactivity and prevalence of HIV among street recruited injection drug users in Los Angeles County, 1994-6

OBJECTIVES

To describe HIV prevalence and the association between syphilis incidence and sexual and drug injection risk behaviours in a cohort of street recruited injecting drug users (IDUs) in Los Angeles County, between 1994 and 1996.

METHODS

During the study period, 513 street recruited African-American and Latino IDUs were screened for syphilis and antibodies to HIV. Subjects were administered a risk behaviour survey at baseline and followed up at 6 month intervals for 18 months with repeated interviews and serological screening. Rate ratios were used to examine associations between syphilis incidence and demographic characteristics and risk behaviours. A proportional hazard model was used to identify predictors of syphilis incidence independent of demographic characteristics.

RESULTS

74% of the sample were male, 70% African-American, 30% Latino; and the median age was 43 years. Overall baseline serological prevalence of HIV was 2.5% and of syphilis 5.7%. None of the participants were co-infected for HIV and syphilis at baseline or at any of the 6 month follow ups. Among 390 eligible IDUs retained for analysis of incidence data, the overall syphilis incidence was 26.0 per 1000 person years. Higher syphilis incidence was found for women compared with men (RR = 2.70; 95% CI 1.60, 4.55), and for those 44 years of age or younger compared with those 45 years of age and older (RR = 2.26; 95% CI 1.25, 4.08). African-Americans were more likely to be syphilis incident cases when compared with Latinos, although the difference did not reach statistical significance (RR = 1.27; 95% CI 0.72, 2.23). In bivariate analysis, risk behaviours significantly associated with higher syphilis incidence included injection of cocaine, "speedball" and heroin, "crack" smoking, recency of first injection event, backloading of syringes, injecting with others, exchanging drugs or money for sex, multiple sex partners, and non-heterosexual sexual preference. Variables that significantly predicted syphilis infection at follow up in the multivariate analysis included multiple sex partners (RR = 7.8; 95% CI 2.4, 25.0), exchanging money for sex (RR = 3.0; 95% CI 0.9, 9.6), and recent initiation to injection drug use (RR = 4.6; 95% CI 1.1, 18.8).

CONCLUSION

Syphilis transmission among IDUs in Los Angeles County remains a serious public health concern, particularly among IDUs who engage in trading of sex for money or drugs. Although low, the prevalence of HIV observed in this study constitutes a serious concern because of the potential for expanded HIV transmission in this susceptible population of IDUs with high syphilis incidence. Enhanced case finding screening efforts and prevention of transmission of sexually transmitted infections should specifically target hard to reach IDUs and their sexual partners.

Use of protease inhibitors among persons with AIDS in Los Angeles County

We evaluated the access to, and the factors associated with, protease inhibitor use among persons with AIDS in Los Angeles County. A population-based sample of adult persons with AIDS is routinely interviewed in Los Angeles County and includes a 30% random sample of men who have sex with men and all other persons reported with AIDS. Since May of 1996, all participants were asked if their physician had ever prescribed a protease inhibitor for their use. The possible association between protease inhibitor use and sociodemographic, temporal and health care factors was assessed for the 12-month period May 1996 through April 1997. Logistic regression was employed for multivariate analysis. Over the 12-month study period, 61.7% (209/339) persons interviewed reported that their physician had prescribed a protease inhibitor as part of their therapy. In bivariate analysis, treatment with protease inhibitor use was more common for whites (71.4%) and US-born Latinos (68.2%) than blacks (53.4%) and foreign-born Latinos (56.6%), among person of higher income (71.2%) than lower (< $10,000) income (50.3%), in those who reported having insurance (66.7%) than those uninsured (47%) and among persons receiving care at private clinics (86.4%) than at HMOs (63.4%) or public clinics (55.2%). An increasing trend of protease inhibitor use with higher educational level and declining CD4+ count was observed. A temporal increase was noted and this trend was most pronounced for persons receiving care at public clinics. In multivariate analysis, persons receiving care at private facilities (adjusted OR = 2.9, 95% CI 1.0, 8.2) and those with higher incomes (adjusted OR = 2.5, 95% CI 1.5, 4.3), were more likely to report that their physician had prescribed a protease inhibitor. The effect of facility type was modified by time. During the first six months of the study period (May 1996-October 1996) persons with AIDS receiving care at public facilities and HMO sites were substantially less likely to report having been offered a protease inhibitor (adjusted OR = 0.13, 95% CI 0.03, 0.58 and adjusted OR = 0.23, 95% CI 0.05, 1.2, respectively). However, no significant facility-specific differences were observed over the last six-month period (November 1997-April 1997) evaluated. Our findings suggest that substantial differences exist in the prescribing and use of protease inhibitors among persons with AIDS in Los Angeles County. Several factors, including facility of HIV care, calendar time, income, education level and level of immunosuppression were independently associated with protease inhibitor use and suggest the existence of important barriers to access. Efforts should be made to identify and remove barriers that will ensure the widest possible access to protease inhibitors for patients with a clinical indication for their use.

Risk factors for trichomoniasis among women with human immunodeficiency virus (HIV) infection at a public clinic in Los Angeles County, California: implications for HIV prevention

Persons with human immunodeficiency virus (HIV) infection who subsequently develop an acute sexually transmitted disease have an increased probability of transmitting HIV. Therefore, characterizing such persons can help direct prevention efforts to a group who are likely to be continuing sources of HIV transmission. We assessed the incidence and factors associated with trichomoniasis in a cohort of HIV-infected women receiving care at a public clinic in Los Angeles County, California from 1992 through 1995. Demographic, clinical, and behavioral data were available from medical records and from patient interviews. Trichomonas infection was the most frequently identified sexually transmitted disease and was found in 37 (17.4%) of 212 women representing a crude incidence rate of 14.1 per 100 person-years experience. The crude rate of trichomoniasis was highest in black women (69.0 per 100 person-years), women with a history of trading sex for drugs or money (51.0 per 100 person-years), those using crack or cocaine (35.5 per 100 person-years), women with four or more sex partners (43.0 per 100 person years), and those born in the United States (23.3 per 100 person-years). Among women with severe immunosuppression (CD4+ count < 200), 18.4% (18 of 98) were diagnosed with trichomoniasis. After multivariate analysis using a Cox proportional hazards approach, black race (adjusted rate ratio [RR] = 5.6, 95% confidence interval [CI] = 2.3, 13.3) continued to be strongly associated with Trichomonas infection. Trading sex for money or drugs (adjusted RR = 25.2, 95% CI = 4.3, 148.6) and single marital status (adjusted RR = 3.7, 95% CI = 1.1, 13.0) were independent risk factors for trichomoniasis in nonblack women but not among black women. Data from this study indicate that Trichomonas may be a frequently acquired infection in HIV-positive women. Our findings suggest that HIV-infected women who are black, and nonblack women who trade sex for money or drugs or are unmarried, are at increased risk of trichomoniasis and therefore may be more likely to transmit HIV infection. Local HIV prevention strategies should target such women for intervention efforts.

HIV prevalence and risk behaviors among patients attending Los Angeles County Tuberculosis Clinics: 1993-1996

PURPOSE

This study aimed to describe prevalence of and risk factors for HIV among persons with newly diagnosed class III (confirmed) and class V (suspected) cases of tuberculosis (TB) patients in Los Angeles County.

METHODS

HIV testing was performed on 1307 blood specimens after routine tests were completed at six TB clinics in Los Angeles County. HIV test results were matched to demographic and risk behavior information by use of an unlinked study methodology.

RESULTS

The overall HIV prevalence rate was 10.8%. By demographic characteristics, the highest prevalence rates were observed among persons born in the United States (15.7%), males (14.1%), blacks (14.3%), and those aged 30-44 years (14.4%). Confirmed TB cases (14%) were more likely to be HIV-infected than were suspect cases (9.6%). Risk behaviors associated with positive HIV serostatus included the injection of nonprescription drugs, having sex with an injection drug user, and use of noninjection forms of heroin, cocaine, and tranquilizers. Men who have sex with men were more likely to be HIV-infected than were heterosexual males.

CONCLUSIONS

HIV testing and counseling should be a standard of care in TB clinics. The observed high HIV prevalence rate reinforces the importance of designing prevention strategies that specifically target patients with TB.

Evidence for recent growth of the HIV epidemic among African-American men and younger male cohorts in Los Angeles County

To estimate the recent course of the human immunodeficiency virus type 1 (HIV) epidemic among men within birth cohorts, ethnic groups, and HIV-risk groups in Los Angeles County, backcalculation methods were combined with log-linear models and census data to reconstruct HIV incidence in subgroups from AIDS surveillance data. Results were compared with directly measured HIV seroprevalence in public sexually transmitted disease (STD) clinics in Los Angeles. Models of HIV incidence indicate that the initial epidemic pattern among men who have sex with men, including a decline in incidence since the mid-1980s, does not apply to all post-1960 birth cohorts. Later peaks were observed in younger birth cohorts and among injection drug users, especially among African-American men, with no evidence of a peak before the 1990s among men born after 1960. Our results indicate that HIV continued to spread near peak rates into the 1990s among younger birth cohorts, especially among young African-American men who have sex with men. Because of the lengthy incubation period from HIV infection to AIDS incidence, our results imply that the AIDS epidemic has not yet peaked in these cohorts and may continue to grow through the present decade in several subgroups. The large variation in HIV incidence and prevalence across birth cohorts and other subgroups needs to be addressed in future community intervention plans.

Epidemiology of isosporiasis among persons with acquired immunodeficiency syndrome in Los Angeles County

To determine factors associated with isosporiasis in persons with acquired immunodeficiency syndrome (AIDS) in Los Angeles County, data from the AIDS surveillance registry were analyzed for the eight-year period 1985-1992. Isosporiasis was reported in 127 (1.0%) of 16,351 persons with AIDS during the study period. Prevalence of infection was highest among foreign-born patients (3.2%), especially those from El Salvador (7.4%) and Mexico (5.4%), and in all persons of Hispanic ethnicity (2.9%). Persons with a history of Pneumocystis carinii pneumonia (PCP) were less likely than PCP-negative patients to have isosporiasis (0.2% and 1.4%, respectively, P < 0.01). A decrease in the prevalence of isosporiasis in patients negative for PCP was observed beginning in 1989 (P = 0.02). Prevalence decreased with age (P < 0.01, by chi-square test for trend). After controlling for multiple factors by logistic regression, isosporiasis was more likely to occur in foreign-born patients than in those born in the United States (adjusted odds ratio [OR] = 5.8, 95% confidence interval [CI] 3.4, 9.9, P < 0.001) and in Hispanics than in whites (non-Hispanics) (adjusted OR = 3.5, 95% CI 1.7, 7.2, P < 0.001). A prior history of PCP continued to be negatively associated with isosporiasis (adjusted OR = 0.2, 95% CI 0.1, 0.3, P < 0.001). Age and time remained independently associated with infection. These data suggest that isosporiasis among persons with AIDS in Los Angeles County may be related to travel exposure and/or recent immigration and that the use of trimethoprim-sulfamethoxazole (TMP-SMX) for PCP may effectively prevent primary infection or expression of latent isosporiasis. Physicians should have an increased index of suspicion for Isospora in AIDS patients with diarrhea who have immigrated from or traveled to Latin America, among Hispanics born in the United States, in young adults, and in those not receiving PCP prophylaxis. Food and water precautions should be advised and TMP-SMX prophylaxis considered for the prevention of Isospora infection for patients with human immunodeficiency virus infection who travel to Latin America and other developing countries.

Emerging patterns of HIV transmission: the value of alternative surveillance methods

OBJECTIVE

To assess the current patterns of HIV transmission in Los Angeles County and determine if AIDS surveillance data accurately reflect these patterns.

DESIGN

Records-based cohort study.

METHODS

The demographic and HIV risk characteristics of persons considered to be recently infected with HIV (CD4+ count > 700 x 10(6)/l) were determined and compared with the characteristics of persons meeting the Centers for Disease Control and Prevention (CDC) 1993 AIDS case definition. Data were obtained for patients with HIV infection enrolled from four HIV outpatient clinics and analyzed between August 1991 and July 1993.

RESULTS

The patient cohort included 1857 persons with HIV infection; 1096 (59.1%) met the CDC 1993 AIDS case definition and 134 (7.2%) had a CD4+ lymphocyte count > 700 x 10(6)/l. The median CD4+ count for the group presumed to be recently infected was 809 x 10(6)/l. Persons considered recently infected with HIV were more likely than those meeting the AIDS case definition to be female (26.1 and 14.5%, respectively; P < 0.001), black (28.4 and 18.2%, respectively; P = 0.001), or male homosexual injecting drug users (IDU; 6.7 and 3.4%, respectively; P = 0.05). After controlling for confounding variables by logistic regression, persons recently infected were more likely to be female [adjusted odds ratio (OR), 3.4; 95% confidence interval (CI), 1.8-6.5; P < 0.001], black (adjusted OR, 1.6; 95% CI, 1.1-2.5; P = 0.02) or male homosexual IDU (adjusted OR, 2.4; 95% CI, 1.1-5.2; P = 0.02) than persons with AIDS.

CONCLUSIONS

Our results suggest that the HIV epidemic in Los Angeles County is currently advancing into different subpopulations and indicate that the current patterns of HIV transmission in the County are not fully reflected in standard AIDS surveillance activities. However, our data must be interpreted cautiously because of potential selection and misclassification biases. These findings illustrate the benefits of alternative surveillance mechanisms in detecting important changes in HIV transmission and defining groups at risk, especially in jurisdictions without HIV reporting.

HIV-1 seroprevalence among women attending sexually transmitted disease clinics in California. California Family of Surveys and Sentinel Surveillance Consortia

To evaluate the distribution of the human immunodeficiency virus type 1 (HIV-1) epidemic among California women, we analyzed HIV-1 seroprevalence and risk factors among women attending sexually transmitted disease (STD) clinics in 21 local health jurisdictions. Using standardized protocols developed by the Centers for Disease Control, we tested unlinked serum specimens from women attending participating STD clinics in 1989. We analyzed demographic characteristics, HIV risk exposure groups, and results of HIV-1 antibody testing on 17,210 specimens with an overall HIV-1 seroprevalence of 0.57%. Seroprevalence rates were highest for African-American women, women 25 to 29 years of age, injection drug users, and women attending STD clinics in San Francisco. After multiple logistic regression analysis, HIV-1 seropositivity remained highest for these four groups. The rate of HIV-1 infection among women attending STD clinics in California underscores the continued need to make HIV counseling and testing an integral component of routine services for women being evaluated for, or presenting with, sexually transmitted diseases.

Lead exposure in stained glass workers

To evaluate lead exposure in stained glass workers, we measured blood lead levels in 12 professional glass workers, in 5 hobbyists, and in 4 workers' family members. Professional workers lead levels (mean 20.7 micrograms/dl) were higher than hobbyists' (11.6 micrograms/dl) (P = 0.02) or family members' (11.3 micrograms/dl). Levels increased with years worked, hours worked per week, and percentage of work involving lead. The mean lead concentration in settled dust samples from a stained glass workshop was 11,000 parts per million. Stained glass workers are at increased risk of lead exposure.