Death sentences for alleged intentional HIV transmission spark international outrage

February 2007

Advanced genome sequencing used by two elite international teams supported their innocence, but a Libyan court sentenced six health care workers to death Dec. 19 for alleged intentional transmission of HIV-1 and hepatitis C virus to hospitalized children.

Five Bulgarian nurses and one Palestinian doctor were accused of deliberately infecting 426 children with HIV in an act of bioterrorism while working at a hospital in Benghazi, Libya.

Fifty-two of the children infected under the accusation of intentional HIV transmission have since died.

The health care workers have been imprisoned in Libya since 1999. The verdict came after a six-year trial that was deemed faulty and scientifically unsubstantiated by watchgroups and scientists.

International medical and human rights groups protested the verdict.

Medical community responds

Using a “molecular clock,” scientists working nonstop in two independent laboratories found that the HIV-strain subtype in question was already circulating and prevalent in the Libyan hospital years before the foreign health care workers arrived in 1998.

“Our calculations show very clearly that the infections started well before 1998. There is no mystery here; the evidence all points to the same answer,” Marco Salemi, PhD, an assistant professor of pathology at the University of Florida College of Medicine, told Infectious Disease News. “The nurses and doctor just arrived at the right time to diagnose the cases.”

A specialist in molecular evolution and DNA sequencing, Salemi and his team were asked to timedate the strains involved in the Libya case concurrently with another team in the United Kingdom. The hope was that they would be able to track the strains before Libyan courts reached a verdict.

Their findings were given to the Libyan court but may not have been considered. The findings were also published in Nature.

DNA sequenced

When charges were first brought against the health care workers, defense lawyers asked a team of Italian scientists to examine the case. The team ran exhaustive tests on collected samples, noting rampant use of dirty needles in the hospital as the cause of infection. The study was dismissed by the Libyan court, according to Salemi.

With another verdict looming, the defense lawyers asked for additional advanced statistical analysis molecular epidemiology from teams at Oxford University in England and the University of Florida. These analyses were to be based on sequences collected for the first study.

The international team used molecular phylogenetic technique to analyze virus sequences based on data from the outbreak origin and employed computations based on math theory developed in the late 1960s and adapted to computers.

Conclusion reached

Nearly half of the 111 children studied in the months after the outbreak showed evidence of both HIV-1 and HCV infection. Sequence analysis of 51 children classified the HIV-1 infections as the strain CRF02_AG and HCV infections were classified as genotype 4 or subtype 1a in 15 children, according to the study.

HIV-1 gag sequences from 44 affected children and 61 HCV E1 E2 gene sequences were analyzed and placed on a timescale of transmission history for the outbreaks, researchers wrote.

Sequencing data indicated that the Libyan HIV strain arose from one CRF02-AG lineage, which is closest to three West African reference sequences. HCV sequences revealed a lineage to Egyptian strains, according to the study.

The epidemiological linkage of the HIV-1 and HCV clusters from the hospital to sequences in sub Saharan Africa was expected because of the large number of migrants to Libya.

To timedate the strains, researchers used the established, bayesian Markov chain Monte Carlo approach and found the most recent ancestor for each cluster was prior to 1998. The probability that the clusters found in the hospital originated after 1998 is almost zero, according to the study.

“Their innocence is beyond any reasonable doubt,” Salemi said.

Human rights concern

Citing the study, officials from UNAIDS, the Joint United Nations Programme on HIV/AIDS, urged Libyan courts to review its decision based on the scientific data.

“By ensuring that the relevant scientific evidence is fully considered in the judicial process, by providing due process for the accused, and by providing treatment, care and support to the children and their families, the government of Libya will ensure that the human rights of all are respected,” UNAIDS officials said in a Dec. 20 statement.

UNAIDS continues to pledge support in treating and preventing HIV/AIDS in Libya.

For more information:

• Oliveira T, Pybus O, Rambaut A, et al. Molecular Epidemiology: HIV-1 and HCV sequences from Libyan Outbreak. Nature. 2006;444:836-837.