HIV prevalence and associated risk factors among men who have sex with men in three regions of Paraguay, 2020.

BACKGROUND: Our study aimed to measure HIV prevalence and associated risk factors among men who have sex with men (MSM) in three regions of Paraguay in 2020. METHODS: MSM were recruited for cross-sectional surveys in three regions of Paraguay using respondent-driven sampling. Interview were conducted face-to-face to collect demographic characteristics and risk and preventive behaviors. The analysis assessed HIV prevalence and associated risk factors in the three samples of MSM within each region. RESULTS: A total of 1,207 MSM were recruited, including 559 in Asunción-Central, 245 in Alto Paraná, and 403 in Caaguazú. HIV prevalence was 24.2% (95% CI 20.6-27.9) in Asunción-Central, 10.2% (95% CI 6.7-14.6) in Alto Paraná, and 3.2% (95% CI 1.7-5.4) in Caaguazú. In Asunción-Central, associations with HIV were age ≥25 years (1.86, 95% CI 1.15-3.00), being employed (1.82, 95% CI 1.07-3.11), self-reporting as homosexual (1.90, 95% CI 1.06-3.43), having sex with a known HIV-positive partner acquisition (4.19, 95% CI 2.37-7.43), self-perceived as being at higher risk for HIV acquisition (4.15, 95% CI 2.54-6.77), and able to access condoms and lubricants (1.82, 95% CI 1.08-3.05). In Alto Paraná, associations with HIV were self-reporting as homosexual (4.33, 95% CI 1.19-15.65) and having higher HIV knowledge (2.53, 95% CI 0.97-6.61). In Caaguazú, associations with HIV were self-reporting as homosexual (7.06, 95% CI 1.53-32.46) and being diagnosed with depression (4.68, 95% CI 0.89-24.43). CONCLUSIONS: HIV prevalence among MSM in Paraguay varied by region, being highest in the capital and major metropolitan area of Asunción-Central, followed by the border area of Alto Paraná. While being self-identified as homosexual was associated with HIV in all three regions, other associations differed, indicating prevention programs need to be tailored to the locale.

Thoracic Bone Tumors Every Radiologist Should Know.

The thoracic cage provides the structural support that makes respiration possible, provides protection to vital organs such as the lungs, heart, liver, and spleen, and serves as an anchor point for the upper extremities. Neoplasms of the bony thorax are not an uncommon incidental finding at both radiography and cross-sectional imaging. Some tumors have a characteristic appearance and it is important that an accurate differential diagnosis be provided. Misidentification could lead to unnecessary imaging or procedures with associated cost, morbidity, and mortality. The purpose of this article is to serve as a quick review of bone tumors commonly encountered in the thorax and that every radiologist should know. Please note that there are also several non-neoplastic osseous lesions that may mimic bone tumors such as osteomyelitis and eosinophilic granuloma; however, these entities are beyond the scope of this review and would not be discussed.

Public health triangulation: approach and application to synthesizing data to understand national and local HIV epidemics.

BACKGROUND: Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and meta-analysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data. METHODS: The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action. RESULTS: Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results. CONCLUSIONS: Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.

Profile of blood donors with serologic tests reactive for the presence of syphilis in São Paulo, Brazil.

BACKGROUND: Syphilis screening of blood donors is a common practice worldwide, but very little is known about the meaning of a positive serologic test for syphilis in blood donors and the risk profile of these donors. The aim of this study was to determine the demographic characteristics and risk behaviors of blood donors with recent and past syphilis and their implications for blood bank testing and deferral strategies. STUDY DESIGN AND METHODS: Demographic characteristics, category of donation, number of previous donations, sexual behavior, and history of sexually transmitted diseases were reviewed comparing blood donors with recent and past syphilis from January 1, 1999, to December 31, 2003. RESULTS: A total of 2439 interviews were reviewed, including 2161 (88.6%) donors with past and 278 (11.4%) with recent syphilis infection. Factors associated with recent infection included younger age (< or = 20 years odds ratio [OR], 36.5; 95% confidence interval [CI], 15.8-84.1), two previous donations (OR, 2.7; 95% CI, 1.9-3.9), male-male sex (homosexual OR, 8.2; 95% CI, 3.2-20.8; and bisexual OR, 11.4; 95% CI, 3.6-36.3), two or more partners in the past 12 months (OR, 2.3; 95% CI, 1.3-4.0), symptoms for syphilis (OR, 4.5; 95% CI, 2.8-7.1), and human immunodeficiency virus (HIV) seropositivity (OR, 39.6; 95% CI, 4.6-339.8). Community donors were also associated with recent syphilis infection (OR, 1.5; 95% CI, 1.2-1.9) compared to replacement donors. CONCLUSION: Sexual history, including male-male sex and multiple partners, were strongly associated with recent syphilis infection, which in turn was strongly associated with HIV. Continuous and vigilant surveillance that includes assessing sexual history and other factors associated with syphilis are needed to guide blood safety policies.

Visual sensitivities tuned by heterochronic shifts in opsin gene expression.

BACKGROUND: Cichlid fishes have radiated into hundreds of species in the Great Lakes of Africa. Brightly colored males display on leks and vie to be chosen by females as mates. Strong discrimination by females causes differential male mating success, rapid evolution of male color patterns and, possibly, speciation. In addition to differences in color pattern, Lake Malawi cichlids also show some of the largest known shifts in visual sensitivity among closely related species. These shifts result from modulated expression of seven cone opsin genes. However, the mechanisms for this modulated expression are unknown. RESULTS: In this work, we ask whether these differences might result from changes in developmental patterning of cone opsin genes. To test this, we compared the developmental pattern of cone opsin gene expression of the Nile tilapia, Oreochromis niloticus, with that of several cichlid species from Lake Malawi. In tilapia, quantitative polymerase chain reaction showed that opsin gene expression changes dynamically from a larval gene set through a juvenile set to a final adult set. In contrast, Lake Malawi species showed one of two developmental patterns. In some species, the expressed gene set changes slowly, either retaining the larval pattern or progressing only from larval to juvenile gene sets (neoteny). In the other species, the same genes are expressed in both larvae and adults but correspond to the tilapia adult genes (direct development). CONCLUSION: Differences in visual sensitivities among species of Lake Malawi cichlids arise through heterochronic shifts relative to the ontogenetic pattern of the tilapia outgroup. Heterochrony has previously been shown to be a powerful mechanism for change in morphological evolution. We found that altering developmental expression patterns is also an important mechanism for altering sensory systems. These resulting sensory shifts will have major impacts on visual communication and could help drive cichlid speciation.

Risk factors for human immunodeficiency virus infection among blood donors in Sao Paulo, Brazil, and their relevance to current donor deferral criteria.

BACKGROUND: The objective of this study was to investigate risk factors of human immunodeficiency virus (HIV)-seropositive blood donors in Brazil and to determine if current donor deferral criteria are appropriate. STUDY DESIGN AND METHODS: Demographic and behavioral data among cases with confirmed HIV seropositivity (n = 272) were compared with those who had a false-positive serology (n = 468) between January 1999 and December 2003 in a case-control analysis with logistic regression. RESULTS: Risk factors that should have resulted in predonation deferral were reported by 48.9 percent of HIV-positive and 9.4 percent of false-positive donors. In multivariate analysis, male cases were significantly more likely to report male-male sex (adjusted odds ratio [AOR], 26.2; 95% confidence interval [CI], 7.8-87.4), a previous sexually transmitted disease diagnosis (AOR, 3.2; 95% CI, 1.5-6.9), exchanging money for sex (AOR, 2.1; 95% CI, 1.0-4.2), and at least two partners in the past 12 months (AOR, 2.3; 95% CI, 1.4-3.6). HIV-positive male donors were also more likely to be reactive for the presence of hepatitis C virus antibody (AOR, 4.0; 95% CI, 1.3-12.0) and hepatitis B virus core antibody (AOR, 3.8; 95% CI, 1.9-7.7). Female cases were more likely to report an intravenous drug user partner (AOR, 12.4; 95% CI, 1.3-120.2), a sexual partner with multiple sex partners or who had a history of sex with a sex worker (AOR, 13.0; 95% CI, 2.7-63.2), and at least two partners in the past 12 months (AOR, 2.2; 95% CI, 1.0-5.3). CONCLUSION: A substantial number of HIV-infected donors reported a risk factor that could have been identified in the predonation screening. Male-male sexual behavior was still the strongest determinant of HIV status in the studied population.

Unrecognized HIV infection, risk behaviors, and perceptions of risk among young men who have sex with men: opportunities for advancing HIV prevention in the third decade of HIV/AIDS.

This study evaluated the magnitude and distribution of unrecognized HIV infection among young men who have sex with men (MSM) and of those with unrecognized infection, the prevalence and correlates of unprotected anal intercourse (UAI), perceived low risk for infection, and delayed HIV testing. MSM aged 15-29 years were approached, interviewed, counseled, and tested for HIV at 263 randomly sampled venues in 6 US cities from 1994-2000. Of 5649 MSM participants, 573 (10%) tested positive for HIV. Of these, 91% of black, 69% of Hispanic, and 60% of white MSM (77% overall) were unaware of their infection. The 439 MSM with unrecognized infection reported a total of 2253 male sex partners in the previous 6 months; 51% had UAI; 59% perceived that they were at low risk for being infected; and 55% had not tested in the previous year. The HIV epidemic among MSM in the United States continues unabated, in part, because many young HIV-infected MSM are unaware of their infection and unknowingly expose their partners to HIV. To advance HIV prevention in the third decade of HIV/AIDS, prevention programs must reduce unrecognized infection among young MSM by increasing the demand for and availability of HIV testing services.

Visual cues eliciting the feeding reaction of a planktivorous fish swimming in a current.

The visual plankivorous feeding behaviour of the shiner perch (Cymatogaster aggregata) was investigated by means of a flow tank operated at various current speeds. Artemia salina was used as prey. In a second set of experiments, Artemia was darkened with black ink, to compare the visually mediated behaviour of C. aggregata while feeding on dark prey vs feeding on natural (i.e. semi-transparent) prey. The positions of the fish and its prey at the time of the feeding reaction of C. aggregata were measured in three dimensions. Prey were on average closer and more in line with the fish's axis when feeding reactions to darkened Artemia were considered, in comparison with natural Artemia. Three potential mechanisms triggering the feeding reaction of C. aggregata were explored: the prey may trigger a reaction in C. aggregata when it reaches a threshold (1) angular size, (2) angular velocity, or (3) rate of change of the angular size (i.e. loom) of the prey as it is carried passively by the current towards the fish. Our results show that angular velocity may trigger the fish's reaction when using semi-transparent prey, while loom may trigger the reaction to darkened prey. This suggests that feeding behaviour of planktivorous fish is flexible and can use different cues to trigger a motor reaction to prey with different visual characteristics. The feeding reaction appeared to occur at longer distances for semi-transparent rather than darkened Artemia. We suggest that semi-transparent Artemia were visible at greater distances because of their higher scattering (i.e. diffuse reflectance) that made them appear brighter when viewed against a dark background.

HIV seroconversion among the homeless and marginally housed in San Francisco: a ten-year study.

HIV seroprevalence was previously found to be 9-11% among the urban homeless in San Francisco, with most infections among injection drug users, men who have sex with men, and those who exchange sex for money or drugs. In this study, HIV incidence and risk factors for seroconversion were estimated among persons who repeatedly participated in cross-sectional serosurveys over a period of 10 years. There were 6 seroconversions among 799 HIV-negative persons, for an incidence rate of 0.30% per person-year (95% CI: 0.12-0.61% per person-year). The seroconversion rate among men who had had recent sex with men was 1.22% per person-year (95% CI: 0.29-3.18) and was 0.52% per person-year (95% CI: 0.19-1.13% per person-year) among those who ever injected drugs. The seroconversion rate among those who were aged <30 years at baseline was 1.67% per person-year (95% CI: 0.40-4.36% per person-year), which was significantly higher than for those age > or =30 years. Policy implications are that HIV resources aimed at the more stable, older homeless population should probably focus on treatment, while prevention efforts, conversely, should probably be targeted to younger homeless persons.

Associations of race/ethnicity with HIV prevalence and HIV-related behaviors among young men who have sex with men in 7 urban centers in the United States.

Using data from a multisite venue-based survey of male subjects aged 15 to 22 years, we examined racial/ethnic differences in demographics, partner type, partner type-specific condom use, drug use, and HIV prevalence in 3316 US black, multiethnic black, Latino, and white men who have sex with men (MSM). We further estimated associations of these factors with HIV infection and their influence on racial/ethnic disparities in HIV prevalence. HIV prevalences were 16% for both black and multiethnic black participants, 6.9% for Latinos, and 3.3% for whites. Paradoxically, potentially risky sex and drug-using behaviors were generally reported most frequently by whites and least frequently by blacks. In a multiple logistic regression analysis, positive associations with HIV included older age, being out of school or work, sex while on crack cocaine, and anal sex with another male regardless of reported condom use level. Differences in these factors did not explain the racial/ethnic disparities in HIV prevalence, with both groups of blacks experiencing more than 9 times and Latinos experiencing approximately twice the fully adjusted odds of infection compared with whites. Understanding racial/ethnic disparities in HIV risk requires information beyond the traditional risk behavior and partnership type distinctions. Prevention programs should address risks in steady partnerships, target young men before sexual initiation with male partners, and tailor interventions to men of color and of lower socioeconomic status.

Regional patterns and correlates of substance use among young men who have sex with men in 7 US urban areas.

OBJECTIVES: We sought to characterize substance use patterns in young men who have sex with men (MSM) in 7 US urban areas and sociodemographic characteristics and history associated with such use. METHODS: We examined data collected from 1994 through 1998 in a venue-based, cross-sectional survey. RESULTS: Among the 3492 participants, 66% reported use of illicit drugs; 28%, use of 3 or more drugs; 29%, frequent drug use (once a week or more); and 4%, injection drug use. These practices were more common among participants who were White, self-identified as bisexual or heterosexual, had run away, or had experienced forced sex. CONCLUSIONS: Effective drug prevention and treatment programs addressing local drug-use patterns and associated factors are urgently needed for young MSM, a population with a high rate of illicit drug use.

Risk behaviors and HIV incidence among repeat testers at publicly funded HIV testing sites in San Francisco.

OBJECTIVE: More than 25% of HIV tests are for individuals who have previously been tested. To characterize repeat testers, we 1) estimated the seroincidence of HIV infection, stratified by risk behavior, and examined the association between 2) testing rates and risk level and 3) repeat testing and tester characteristics. METHODS: Records from HIV counseling and testing (C&T) sites were reviewed. Seroincidence was estimated by linking results of current test with date of last reported HIV negative test. A risk hierarchy of behaviors was created. Repeat testing rates were calculated for each risk level strata. Multivariate models explored the association of repeat testing with tester characteristics. RESULTS: The HIV seroincidence among repeaters was 1.3 per 100 person-years (range 0.7-7.0 per 100 person-years). The high-risk level subject had a repeater rate of 92%, with 5.3 tests/person and was more likely (odds ratio = 4.96, 95% confidence interval 3.8-6.5) to have tested two or more times, compared with those in the low risk group. CONCLUSION: The highest users of repeat testing are those who are practicing the highest risk behaviors and have the highest incidence of HIV. This suggests that prevention messages should be modified to more explicitly address the behaviors that are putting individuals at high risk for HIV.

Impact of highly active antiretroviral treatment on HIV seroincidence among men who have sex with men: San Francisco.

OBJECTIVES: This study assessed the countervailing effects on HIV incidence of highly active antiretroviral treatment (HAART) among San Francisco men who have sex with men (MSM). METHODS: Behavioral risk was determined on the basis of responses to cross-sectional community interviews. HIV incidence was assessed through application of an enzyme-linked immunoassay testing strategy. RESULTS: Use of HAART among MSM living with AIDS increased from 4% in 1995 to 54% in 1999. The percentage of MSM who reported both unprotected anal intercourse and multiple sexual partners increased from 24% in 1994 to 45% in 1999. The annual HIV incidence rate increased from 2.1% in 1996 to 4.2% in 1999 among MSM who sought anonymous HIV testing, and the rate was high (5.3%) but stable in a blinded survey of MSM seeking sexually transmitted disease services. CONCLUSIONS: Any decrease in per contact risk of HIV transmission due to HAART use appears to have been counterbalanced or overwhelmed by increases in the number of unsafe sexual episodes.

Repeat HIV testing, risk behaviors, and HIV seroconversion among young men who have sex with men: a call to monitor and improve the practice of prevention.

OBJECTIVES: We compared recent risk behaviors and HIV seroconversion among young men who have sex with men (MSM) who were first-time, infrequent, and repeat HIV testers. METHODS: Male adolescents and young men aged 15 to 22 years were randomly sampled, interviewed, counseled, and tested for HIV at 194 gay-identified venues in seven U.S. cities from 1994 through 1998. Analyses were restricted to MSM who reported having never tested or last tested HIV-negative. RESULTS: Of 3430 participants, 36% tested for the first time, 39% had tested infrequently (one or two times), and 26% had tested repeatedly (> or = three times). Compared with first-time testers, repeat testers were more likely to report recent risk behaviors and to acquire HIV (7% versus 4%). Over 75% of repeat testers who seroconverted acquired HIV within 1 year of their last test. Compared with repeat testers, first-time testers reported similar use of health care but delayed testing for nearly 2 additional years after initiating risk. CONCLUSIONS: Many young MSM soon acquire HIV after repeated use of HIV counseling and testing services. Providers must strengthen practices to identify, counsel, and test young MSM and provide enhanced behavioral interventions for those with persistent risks.