Mapping HIV clustering: a strategy for identifying populations at high risk ofHIV infection in sub-Saharan Africa

International Journal of Health Geographics

Laith J Abu-Raddad¹  Susanne F Awad²  Diego F Cuadros³ 

[1] Vaccine and Infectious Disease Division, Fred Hutchinson Cancer ResearchCenter, Seattle, WA, USA;Infectious Disease Epidemiology Group, Weill Cornell Medical College –Qatar, Qatar Foundation - Education City, P.O. Box 24144, Doha, Qatar;Department of Public Health, Weill Cornell Medical College, CornellUniversity, New York, NY, USA

关键词: Mathematical modeling;    Sub-Saharan Africa;    Disease mapping;    Spatial epidemiology;    HIV;   

Others  :  810126
DOI  :  10.1186/1476-072X-12-28

 received in 2013-03-02, accepted in 2013-05-15,  发布年份 2013

【 摘 要 】

Background

The geographical structure of an epidemic is ultimately a consequence of the drivers of the epidemic and the population susceptible to the infection. The ‘know your epidemic’ concept recognizes this geographical feature as a key element for identifying populations at higher risk of HIV infection where prevention interventions should be targeted. In an effort to clarify specific drivers of HIV transmission and identify priority populations for HIV prevention interventions, we conducted a comprehensive mapping of the spatial distribution of HIV infection across sub-Saharan Africa (SSA).

Methods

The main source of data for our study was the Demographic and Health Survey conducted in 20 countries from SSA. We identified and compared spatial clusters with high and low numbers of HIV infections in each country using Kulldorff spatial scan test. The test locates areas with higher and lower numbers of HIV infections than expected under spatial randomness. For each identified cluster, a likelihood ratio test was computed. A P-value was determined through Monte Carlo simulations to evaluate the statistical significance of each cluster.

Results

Our results suggest stark geographic variations in HIV transmission patterns within and across countries of SSA. About 14% of the population in SSA is located in areas of intense HIV epidemics. Meanwhile, another 16% of the population is located in areas of low HIV prevalence, where some behavioral or biological protective factors appear to have slowed HIV transmission.

Conclusions

Our study provides direct evidence for strong geographic clustering of HIV infection across SSA. This striking pattern of heterogeneity at the micro-geographical scale might reflect the fact that most HIV epidemics in the general population in SSA are not far from their epidemic threshold. Our findings identify priority geographic areas for HIV programming, and support the need for spatially targeted interventions in order to maximize the impact on the epidemic in SSA.

【 授权许可】

   
2013 Cuadros et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 2.

Figure 3.

Figure 4.

【 参考文献 】

• [1]UNAIDS/WHO: AIDS epidemic update 2010: UNAIDS fact sheet. available at http://www.unaids.org/documents/20101123_FS_SSA_em_en.pdf webcite, accessed 23 July 2012
• [2]Abu-Raddad LJ, Barnabas RV, Janes H, Weiss HA, Kublin JG, Longini IMJ, Wasserheit JN, Group tHVLW: Have the explosive HIV epidemics in sub-Saharan Africa been driven by higher community viral load? AIDS 2012.
• [3]UNAIDS: Practical guidelines for intensifying HIV prevention: towards universal acces. Book Practical guidelines for intensifying HIV prevention: towards universal acces 2007.
• [4]Wilson D, Halperin DT: Know your epidemic, know your response: a useful approach, if we get it right. Lancet 2008, 372:423-426.
• [5]Buse K, Dickinson C, Sidibé M: HIV: know your epidemic, act on its politics. JRSM 2008, 101:572-573.
• [6]Fichtenberg CM, Ellen JM: Moving from core groups to risk spaces. Sex Transm Dis 2003, 30:825-826.
• [7]Real LA, Biek R: Spatial dynamics and genetics of infectious diseases on heterogeneous landscapes. J R Soc Interface 2007, 4:935-948.
• [8]Demographic and health surveys http://www.measuredhs.com/ webcite
• [9]Kulldorff M: A spatial scan statistic. Comm Stat Theor Meth 1997, 26:1481-1496.
• [10]Wand H, Ramjee G: Targeting the hotspots: investigating spatial and demographic variations in HIV infection in small communities in South Africa. J Int AIDS Soc 2010, 13:41. BioMed Central Full Text
• [11]Ryan J, Mbui J, Rashid J, Wasunna M, Kirigi G, Magiri C, Kinoti D, Ngumbi P, Martin S, Odera S: Spatial clustering and epidemiological aspects of visceral Leishmaniasis in two endemic villages, Baringo District, Kenya. Am J Trop Med Hyg 2006, 74:308-317.
• [12]Kulldorf M, Song C, Gregoria D, Samociuk H, DeChello L: Cancer map patterns: are they random or not? Am J Prev Med 2006, 30:s37-s49.
• [13]Aamodt G, Samuelsen S, Skrondal A: A simulation study of three methods for detecting disease clusters. Int J Health Geogr 2006, 5:15. BioMed Central Full Text
• [14]Kulldorf M, Zhang Z, Hartman J, Heffernan R, Huang L, Mostashari F: Benchmark data and power calculations for evaluating disease outbreak detection methods. MMWR 2004, 53:144-151.
• [15]ESRI: ArcGIS 9.x. Redlands, CA, USA: ESRI; 2004.
• [16]Abu-Raddad LJ, Longini IM Jr: No HIV stage is dominant in driving the HIV epidemic in sub-Saharan Africa. AIDS 2008, 22:1055-1061.
• [17]Abu-Raddad LJ, Patnaik P, Kublin JG: Dual infection with HIV and malaria fuels the spread of both diseases in sub-Saharan Africa. Science 2006, 314:1603-1606.
• [18]Awad S, Cuadros D, Abu-Raddad L: Characterizing HIV prevalence distribution across sub-populations at variable levels of sexual behavior. Int J Infect Dis 2012, 16(Supplement 1):e180-e181.
• [19]Weiss HA, Halperin D, Bailey RC, Hayes RJ, Schmid G, Hankins CA: Male circumcision for HIV prevention: from evidence to action? AIDS 2008, 22:567-574. 510.1097/QAD.1090b1013e3282f1093f1406
• [20]Abu-Raddad LJ, Magaret AS, Celum C, Wald A, Longini IM Jr, Self SG, Corey L: Genital herpes has played a more important role than any other sexually transmitted infection in driving HIV prevalence in Africa. PLoS One 2008, 3:e2230.
• [21]Heffron R, Donnell D, Rees H, Celum C, Mugo N, Were E, de Bruyn G, Nakku-Joloba E, Ngure K, Kiarie J: Use of hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort study. Lancet Infect Dis 2012, 12:19-26.
• [22]Kaul R, Cohen CR, Chege D, Yi TJ, Tharao W, McKinnon LR, Remis R, Anzala O, Kimani J: Biological factors that may contribute to regional and racial disparities in HIV prevalence. Am J Reprod Immunol 2011, 65:317-324.
• [23]Morris M, Kretzschmar M: Concurrent partnerships and the spread of HIV. AIDS 1997, 11:641-648.
• [24]Auvert B, Buvé A, Ferry B, Caraël M, Morison L, Lagarde E, Robinson NJ, Kahindo M, Chege J, Rutenberg N: Ecological and individual level analysis of risk factors for HIV infection in four urban populations in sub-Saharan Africa with different levels of HIV infection. AIDS 2001, 15:S15-S30.
• [25]Leclerc PM, Garenne M: Commercial sex and HIV transmission in mature epidemics: a study of five African countries. Int J STD AIDS 2008, 19:660-664.
• [26]Brown MS: Coitus, the proximate determinant of conception: inter-country variance in sub-Saharan Africa. J Biosoc Sci 2000, 32:145-159.
• [27]Anderson R, May R: Infectious Diseases of Humans: Dynamics And Control. Oxford: Oxford University Press; 1991.
• [28]Marston M, Harriss K, Slaymaker E: Non-response bias in estimates of HIV prevalence due to the mobility of absentees in national population-based surveys: a study of nine national surveys. Sex Transm Infect 2008, 84(Suppl 1):i71-i77.
• [29]Mishra V, Barrere B, Hong R, Khan S: Evaluation of bias in HIV seroprevalence estimates from national household surveys. Sex Transm Infect 2008, 84(Suppl 1):i63-i70.
• [30]Chen L, Jha P, Stirling B, Sgaier SK, Daid T, Kaul R, Nagelkerke N, for the International Studies of HIVAI: Sexual Risk Factors for HIV Infection in Early and Advanced HIV Epidemics in Sub-Saharan Africa: Systematic Overview of 68 Epidemiological Studies. PLoS One 2007, 2:e1001.
• [31]UNAIDS: UNAIDS Report on the Global AIDS Epidemic 2010. In Book UNAIDS Report on the Global AIDS Epidemic 2010. City; 2010.
• [32]UNAIDS/WHO: Global HIV/AIDS response: Epidemic update and health sector progress towards Universal Access.