Digital epidemiology.

Mobile, social, real-time: the ongoing revolution in the way people communicate has given rise to a new kind of epidemiology. Digital data sources, when harnessed appropriately, can provide local and timely information about disease and health dynamics in populations around the world. The rapid, unprecedented increase in the availability of relevant data from various digital sources creates considerable technical and computational challenges.

Blind spots in the epidemiology of HIV in black Americans.

In the USA, annual rates of new human immunodeficiency virus (HIV)/AIDS diagnoses are seven and 21 times higher in black men and women, respectively, than in whites. Epidemiological inquiry on this disparity has chiefly focused on contextual factors; such emphasis has eclipsed study of direct HIV vectors. The US Centers for Disease Control and Prevention recently announced its intention to curb HIV propagation in black communities, recommending culturally appropriate HIV/AIDS strategies. Contemplated societal interventions should be informed by data evaluating more direct (and under-assessed) HIV transmission vectors, specifically anal intercourse and unsuspected blood exposures. This recommendation involves tracing sexual and non-sexual contacts of recently infected persons and uninfected controls, coupled with DNA sequencing of HIV isolates. Public health authorities do not know the extent to which unmeasured yet plausible HIV transmission vectors can account for ethnic disparities. Appropriate prevention strategies depend critically on direct, rather than ecologic, evidence.

Improved injection network ascertainment with supplementary elicitation techniques.

Prior research indicates that injection drug users forget substantial proportions of their injection partners when asked to recall them. Such under-reporting hampers both ascertainment of the injection networks that underlie transmission of blood-borne pathogens and contact-tracing efforts for disease control. We report here an evaluation of supplementary elicitation techniques--a set of prompting strategies and recall cues--employed in a study that involved tracing of injection partners. Sixty-one index drug injectors in Seattle participated in the study. The supplementary partner elicitation techniques enhanced recall of injection partners substantially and identified persons relevant to transmission of blood-borne pathogens. As a set, the supplementary techniques elicited additional partners from 70% of injectors, and the additional partners elicited represent a 75% increase on average. Drug injectors who recalled many partners before administration of the supplementary techniques tended to report more additional partners in response to the supplementary techniques than injectors who freely recalled few partners. In addition, partners elicited by the supplementary techniques were as likely as freely recalled partners to test positive for hepatitis C virus antibody and engage in risk behaviour with indexes. Furthermore, we found that the supplementary techniques boosted connectivity in the observed injection network considerably.

Male and female circumcision associated with prevalent HIV infection in virgins and adolescents in Kenya, Lesotho, and Tanzania.

PURPOSE: Remarkable proportions of self-reported virgins and adolescents in eastern and southern Africa are infected with HIV, yet non-sexual routes of transmission have not been systematically investigated in such persons. Many observers in this region have recognized the potential for HIV transmission through unhygienic circumcision procedures. We assessed the relation between male and female circumcision (genital cutting) and prevalent HIV infection in Kenyan, Lesothoan, and Tanzanian virgins and adolescents. METHODS: We analyzed data from recent cross-sectional national probability sample surveys of adolescents and adults in households, focusing on populations in which circumcision was common and usually occurred in puberty or later. RESULTS: Circumcised male and female virgins were substantially more likely to be HIV infected than uncircumcised virgins (Kenyan females: 3.2% vs. 1.4%, odds ratio [OR] = 2.38; Kenyan males: 1.8% vs. 0%, OR undefined; Lesothoan males: 6.1% vs. 1.9%, OR 3.36; Tanzanian males: 2.9% vs. 1.0%, OR 2.99; weighted mean phi correlation = 0.07, 95% confidence interval, 0.03 to 0.11). Among adolescents, regardless of sexual experience, circumcision was just as strongly associated with prevalent HIV infection. However, uncircumcised adults were more likely to be HIV positive than circumcised adults. Self-reported sexual experience was independently related to HIV infection in adolescent Kenyan females, but was unrelated to HIV infection in adolescent Kenyan, Lesothoan, and Tanzanian males. CONCLUSIONS: HIV transmission may occur through circumcision-related blood exposures in eastern and southern Africa.

Peer referral for HIV case-finding among men who have sex with men.

OBJECTIVE: To evaluate the effectiveness and cost-effectiveness of a health department-based peer referral program for identifying previously undiagnosed cases of HIV among men who have sex with men (MSM). DESIGN AND METHODS: Between 2002 and 2005, 283 MSM peer recruiters were enrolled in a public health program in King County, Washington, USA. Peer recruiters were enrolled from a sexually transmitted disease (STD) clinic, an HIV clinic, via media advertisements and through collaboration with community-based organizations (CBO). The peer recruiters underwent a brief training and were then paid US$ 20 for each peer they referred to be tested for HIV, STD and viral hepatitis. Peers were paid US$ 20 for being tested. The main outcome measure was the number of new cases of HIV identified and cost per case of HIV identified. RESULTS: Recruiters referred 498 peers for HIV, STD and hepatitis testing. Among 438 peers not previously diagnosed with HIV, 22 (5%) were HIV positive, of whom 18 received their HIV test results. Other infections were variably prevalent among tested peers: gonorrhea [23/307 (8%)], chlamydia [6/285 (2%)], syphilis [1/445 (0.2%)], hepatitis C [61/198 (31%)], surface antigen positive hepatitis B [8/314 (3%)]. Excluding the costs of testing for viral hepatitis and STDs other than HIV, the cost per new HIV case identified was US$ 4929. During the same period, the cost per new case of HIV detected through bathhouse-based HIV testing and through the county's largest CBO-based HIV testing program were US$ 8250 and US$ 11 481, respectively. CONCLUSIONS: Peer referral is an effective means of identifying new cases of HIV among MSM.

Extent, trends, and perpetrators of prostitution-related homicide in the United States.

Prostitute women have the highest homicide victimization rate of any set of women ever studied. We analyzed nine diverse homicide data sets to examine the extent, trends, and perpetrators of prostitution-related homicide in the United States. Most data sources substantially under-ascertained prostitute homicides. As estimated from a conservative capture-recapture analysis, 2.7% of female homicide victims in the United States between 1982 and 2000 were prostitutes. Frequencies of recorded prostitute and client homicides increased substantially in the late 1980s and early 1990s; nearly all of the few observed pimp homicides occurred before the late 1980s. These trends may be linked to the rise of crack cocaine use. Prostitutes were killed primarily by clients, clients were killed mainly by prostitutes, and pimps were killed predominantly by pimps. Another conservative estimate suggests that serial killers accounted for 35% of prostitute homicides. Proactive surveillance of, and evidence collection from, clients and prostitutes might enhance the investigation of prostitution-related homicide.

A Social Network Analysis of 140 Community-Academic Partnerships for Health: Examining the Healthier Wisconsin Partnership Program.

INTRODUCTION: Social Network Analysis (SNA) provides an important, underutilized approach to evaluating Community Academic Partnerships for Health (CAPHs). This study examines administrative data from 140 CAPHs funded by the Healthier Wisconsin Partnership Program (HWPP). METHODS: Funder data was normalized to maximize number of interconnections between funded projects and 318 non-redundant community partner organizations in a dual mode analysis, examining the period from 2003-2013.Two strategic planning periods, 2003-2008 vs. 2009-2014, allowed temporal comparison. RESULTS: Connectivity of the network was largely unchanged over time, with most projects and partner organizations connected to a single large component in both time periods. Inter-partner ties formed in HWPP projects were transient. Most community partners were only involved in projects during one strategic time period. Community organizations participating in both time periods were involved in significantly more projects during the first time period than partners participating in the first time period only (Cohen's d = 0.93). DISCUSSION: This approach represents a significant step toward using objective (non-survey) data for large clusters of health partnerships and has implications for translational science in community settings. Considerations for government, funders, and communities are offered. Examining partnerships within health priority areas, orphaned projects, and faculty ties to these networks are areas for future research.

Knowledge of specific HIV transmission modes in relation to HIV infection in Mozambique.

BACKGROUND: In prior research, Africans who knew about blood-borne risks were modestly less likely to be HIV-infected than those who were not aware of such risks. OBJECTIVES/METHODS: I examined the association between knowledge of specific HIV transmission modes and prevalent HIV infection with data from the 2009 Mozambique AIDS Indicator Survey. RESULTS: Respondents displayed high awareness of blood exposures and vaginal sex as modes of HIV transmission. However, only about half of respondents were aware of anal sex as a way HIV can be transmitted. After adjustments for demographics and sexual behaviors, respondents who knew that HIV could spread by contact with infected blood or by sharing injection needles or razor blades were less likely to be infected than those who did not know about these risks. Respondents who knew about sexual risks were as, or more, likely to be HIV infected as those who did not know about sexual risks. Also, children of HIV-uninfected mothers were less likely to be infected if their mothers were aware of blood-borne HIV risks than if their mothers were unaware. CONCLUSION: HIV education campaigns in Mozambique and elsewhere in sub-Saharan Africa should include a focus on risks from blood exposures and anal sex.

A systematic review of cervical artificial disc replacement wear characteristics and durability.

STUDY DESIGN: Systematic review.Clinical questions: (1) What evidence is available from studies of cervical total disc arthroplasty (C-ADR) failure and retrieval regarding durability, wear, and reasons for failure of C-ADR? (2) What evidence is available from experimental models regarding the durability of C-ADR beyond 5 years? METHODS: We searched electronic databases to identify published reports of explanted cervical artificial discs and biomechanical simulations of disc wear. RESULTS: Nine articles were identified describing 17 devices explanted from human patients and four articles describing 23 devices explanted from non-human subjects. Wear properties were not consistently reported across studies, so summaries for specific variables are based on few cases. No device had been implanted longer than 4 years. In both human and non-human subjects, devices showed evidence of metallic and polymeric (for discs with polymer components) debris. Inflammatory cells were frequently present in surrounding soft tissues. Signs of infection were uncommon.Four patients had reactions interpreted as hypersensitivity to metal. We identified three articles on biomechanical wear simulations. Devices were tested between 10 and 20 million cycles in axial loading, flexion/extension, and lateral bending. No device failures were reported. One study suggests such simulations may represent 50 or more years of wear in actual patients. CONCLUSION: Cervical disc implants consistently produced polymeric and metallic debris, which was typically accompanied by inflammation. Hypersensitivity to metal may increase risk for device failure. Biomechanical simulations indicate that cervical disc implants may be durable beyond the currently reported length of clinical follow-up.

Knowledge of blood-borne transmission risk is inversely associated with HIV infection in sub-Saharan Africa.

INTRODUCTION: Accurate, comprehensive knowledge of an infectious pathogen's modes of transmission helps people to avoid infection. Growing evidence suggests that blood-borne HIV transmission is widespread in sub-Saharan Africa. METHODOLOGY: I examined the association between knowledge of blood-borne HIV risk and prevalent HIV infection in Demographic and Health Survey data from 16 sub-Saharan African countries. I also searched three online databases for evidence of public education campaigns focused on blood-borne HIV risks in these countries. RESULTS: Knowledge was moderately to strongly inversely related to HIV prevalence at the national level (i.e., countries in which many respondents were aware of blood-borne risk had lower HIV prevalence than countries in which few respondents were aware of such risk). At the individual level, respondents who knew about blood-borne HIV risks were modestly less likely to be infected than those who did not show awareness of this risk, independent of demographic and sexual behavior variables. This relationship was stronger in southern Africa than in west, central, and east Africa. In parallel analyses, knowledge of condom use as a way to prevent HIV was positively associated with prevalent HIV infection at both the national and individual levels. West, central, and east African countries with low to moderate HIV prevalence had implemented public education campaigns that included a focus on blood-borne transmission risks. Such campaigns were absent from high prevalence countries in southern Africa. CONCLUSION: These findings suggest that knowledge of blood-borne HIV risk protects against HIV infection and that public education campaigns are important for spreading that knowledge. 

HCV and HIV prevalences strongly correlated in Asian communities with reservoirs of HIV in high-risk groups.

BACKGROUND: In some Asian communities, HIV epidemics initially concentrated in high-risk groups develop into generalized epidemics, while in others HIV epidemics remain confined to high-risk groups. We examined whether blood exposures in a community, as indicated by hepatitis C virus (HCV) prevalence, can account for the variability in HIV prevalence in Asia. METHODOLOGY: We searched the published literature for temporally comparable HCV and HIV prevalence estimates for pregnant women and other "low-risk" population segments in Asian communities with established HIV epidemics in injection drug users or prostitute women. We assessed the correlation between HCV and HIV prevalences in these communities. RESULTS: HCV and HIV prevalences were strongly correlated (r = .97, p < .001). CONCLUSION: This finding suggests that blood-borne transmission drives generalized HIV epidemics in Asia and highlights the need for appropriately designed investigations of transmission modes.