Roka Commune outbreak
In November 2014, a 74-year old man in Roka Commune, Cambodia, tested HIV-positive. He sent his granddaughter and son-in-law for tests. They also tested positive. Alarmed by these unexpected HIV infections, more residents of Roka Commune went for tests; many were HIV-positive.
The next month, December 2014, Cambodia’s Ministry of Health initiated an investigation with collaboration from WHO, the US CDC, UNAIDS, UNICEF, and the Pasteur Institute in Cambodia.
Three papers report results from this investigation.[2,3,4] Results are limited to 242 persons testing HIV-positive through end-February 2015. Comparing HIV-positive residents with neighbors, infected residents had received more injections, infusions, and blood tests. Reports say nothing about specific failures in infection control (e.g., did providers give injections after changing needles but reusing syringes? did providers give infusions with reused plastic tubes and saline bags?). Many persons were co-infected with hepatitis C, which unsafe healthcare had been spreading in the community for years before the HIV outbreak.
Foreign organizations helping with the investigation sequenced several hundred HIV (determined the order of their constituent molecules) from the community. Almost all sequences were very similar, showing fast transmission from 1 to 198 infections in a few short years. These sequences can be presented as branches in a “tree” (see below, Figure 1). The upper right section of the tree shows the cluster of very similar sequences from Roka. (Most sequences in the lower part of the tree are “controls,” which means the HIV came from other times and places.) The tree shows each HIV infection as the right end-point of a short horizontal line. The left ends of these lines show estimated connections to earlier estimated infections. The timeline at the bottom of the figure shows time going from left to right, showing the estimated dates of transmission from earlier to later infections.
Figure 1: Cluster of 198 infections in Roka, Cambodia, linked by transmissions during 2011-14
Using information from these reports, one of the managers of this website (DG) estimated the transmission efficiency of HIV through contaminated injection equipment at 4.6%-9.2% (this is the risk that an injection administered to an HIV-positive person during the outbreak transmitted HIV to a subsequent patient).
Other information related to the Roka outbreak
In early 2017, a newspaper article reported 292 infections in the outbreak.
As in many other nosocomial HIV outbreaks, children were on the front lines: 22% of cases were in children <14 years old.
Alerted by the investigation, people looked for unexpected infections and unsafe practices elsewhere in Cambodia. A December 2015 BBC article – one year after Roka broke into public view – reports continued and common unsafe practices. In mid-February 2016, an NGO reported 14 patients testing HIV-positive – 10 from Peam village in Kandal Province, a village of 1,000, and 4 from neighboring villages. The article reported 32 previously known infections in Peam village, for a total of 42 or 4.2% of 1,000 villagers. In interviews, persons newly identified with HIV denied sexual risks and suspected infection from injections by a specified local doctor.
See also these dontgetstuck.org blogs posts
1. Eng Sarath. Ministry of Health, Cambodia. 24 December 2014. HIV cases in Sangke district, Battambang. Available at: http://www.cdcmoh.gov.kh/97-hiv-cases-in-sangke-district-battambang
2. Mean Chhi Vun et al. Cluster of HIV infections attributed to unsafe injections – Cambodia December 1, 2014-February 28, 2015. Morbidity and Mortality Weekly Report 2016: 65: 142-145. Available at: http://www.cdc.gov/mmwr/volumes/65/wr/mm6506a2.htm (accessed 28 March 2016).
3. Saphonn V, Fujita M, Samreth S, et al. Cluster of HIV infections associated with unsafe injection practices in a rural village in Cambodia. J Acquir Immune Defic Syndr 2017; 75: 285-e86. Available at: https://journals.lww.com/jaids/Citation/2017/07010/Cluster_of_HIV_Infections_Associated_With_Unsafe.19.aspx (accessed 12 February 2018).
4. Rouet F, Nouhin J, Zheng D-P, et al. Massive iatrogenic outbreak of human immunodeficiency virus type 1 in rural Cambodia, 2014-2015. Clin Infect Dis 2017; epub ahead of print. Available at: https://academic.oup.com/cid/advance-article-abstract/doi/10.1093/cid/cix1071/4689456?redirectedFrom=PDF (accessed 12 February 2018).
5. Roka/HIV/bayesian_timetree. Evolutionary and epidemiological analysis of the Roka HIV outbreak. Bedford Lab. Available at: https://bedford.io/projects/roka/HIV/bayesian_timetree/ (accessed 15 November 2018). This figure has been copied by permission from Bedford Lab.
6. Gisselquist D. HIV transmission efficiency through contaminated injections in Roka, Cambodia. biorxiv 2017. Available at: https://www.biorxiv.org/content/biorxiv/early/2017/05/15/136135.full.pdf (accessed 12 February 2018).
7. Millar P. How the residents of Cambodia’s “HIV village” are coping more than two years on. Southeast Asia Globe, 15 March 2017. Available at: http://sea-globe.com/how-the-residents-of-cambodias-hiv-village-are-coping-more-than-two-years-on/ (accessed 14 August 2017.
8. John Murphy. BBC, 17 December 2015. A country in love with injections and drips.
Available at: http://www.bbc.com/news/magazine-35111566
9. Aun Pheap, George Wright. Doctor denies spreading HIV in latest outbreak. Cambodia Daily News 22 February 2016. Available at: https://www.cambodiadaily.com/news/doctor-denies-spreading-hiv-in-latest-outbreak-108791/ (accessed 28 March 2016).
Kehumile Mazibuko. News Tonight Africa, 4 December 2015. Cambodia: unlicensed medical practitioner sentenced for infecting more than 100 people with HIV. Available at: http://newstonight.co.za/content/cambodia-unlicensed-medical-practitioner-sentenced-infecting-more-100-people-hiv
Khy Sovuthy, Anthony Jensen. Cambodia Daily, 8 December 2015. In HIV case, key evidence trails behind guilty verdict. Available at: https://www.cambodiadaily.com/news/in-hiv-case-key-evidence-trails-behind-guilty-verdict-102320/