New molecular evidence, published online by Nature tonight — “Molecular epidemiology: HIV-1 and HCV sequences from Libyan outbreak” — and supplementary info — see here — provides a firm alibi for the six medical workers facing the death penalty in Libya. They are charged with deliberately contaminating more than 400 children with HIV in 1998.
An international team has used the genetic sequences of the viruses isolated from the patients to reconstruct the exact history, or “family tree” of the outbreak. Analysing mutations that accumulate over time has allowed the researchers to work out when different events occurred. The Brief Communication shows that the subtype of HIV involved was present and spreading locally well before the medical workers arrived in Libya in 1998.
The trial of the six ended in Tripoli on 4 November, and a verdict is expected on 19 December. A body of scientific evidence already indicates that the outbreak was caused not by deliberate transmission, but by poor hospital hygiene. These results, by Tulio de Oliveira and colleagues, provide the first independent molecular confirmation.
Iâ€™ve an accompanying news article — Molecular HIV evidence backs accused medics — that discusses the case case and how important this new evidence could be — the full pdf, with box is here. Phylogenetic HIV analyses have been used in court cases worldwide involving allegations of accidental or deliberate HIV infection. Thomas Leitner of Los Alamos National Laboratory has provided forensic HIV evidence in more than 30 such cases over the past 15 years. He describes the Nature paper as “compelling evidence that the outbreak had started before the accused could have started it.”
The news article cites several other assessments by scientists who have been involved in HIV phylogenetic evidence presented in court cases of the new findings.
Here are two more comments, that came in after we had gone to press:
“The scientific data presented by de Oliveria et al. convincingly establish multiple infections in the children prior to the arrival of the Bulgarian staff in March, 1998 at the hospital. These data sufficiently refute any connection with the staff, directly or indirectly. This is a real travesty given the refusal by the Libyan courts to consider key scientific evidence that gets to the truth of the matter.”
Mike Metzker, Baylor College of Medicine, Human Genome Sequencing Center
“Using state of the art evolutionary analyses, they demonstrate that the likely dates for the most-recent common ancestors (MRCAs) of the HCV and HIV-1 viral sequences pre-date the presence of the Bulgarian nurses in the Al-Fateh Hospital. Taken as a whole, the results of the analyses of de Oliveira et al. are highly inconsistent with the allegations of the Libyan prosecutors.”
Gerald Learn, evolutionary geneticist at the University of Washington