HIV group N case detected outside Cameroon for the first time

A rare type of HIV-infection -- group N -- has been diagnosed in a man in France who recently travelled to Togo, meaning that it has been detected outside Cameroon for the first time. This type of HIV infection is much more similar to the virus type found in chimpanzees than it is to other types circulating in humans. The circumstances are described in a Case Report in this week's issue of the Lancet, written by Professor François Simon, INSERM U 941, Faculté de Médecine Paris-Diderot, Hôpital Saint-Louis, Paris and colleagues from the National Reference Centre for HIV, Rouen, France.

Most types of HIV in humans are either group M, or less commonly, group O. The first case of group N was diagnosed in a woman living in Cameroon in 1998, and since then only 12 cases, including two couples infected by the same strains, have been identified, all in Cameroon. In 2009, a fourth group, designated as P, was identified in a Cameroonian woman living Paris.

In this new group N case, a 57-year-old man living in France attended an emergency unit Hôpital Saint-Louis with fever, rash, swollen lymph glands, and genital ulceration, 8 days after returning from Togo. He reported sexual contact with a Togolese partner, and HIV primary infection was suspected. Once HIV was detected, it was profiled and the authors say they were surprised to see that the virus did not match up with standard types.

They add that this case of primary HIV-N infection is particularly important because the severe clinical manifestations and early decline in CD4 cell count. A five-drug antiretroviral combination showed good initial efficacy, but longer-term immunological and virological follow-up is needed.

The authors conclude: "This case of HIV-1 group-N primary infection indicates that this rare group is now circulating outside Cameroon, which emphasises the need for rigorous HIV epidemiological monitoring."

Professor François Simon, INSERM U 941, Faculté de Médecine Paris- Diderot, Hôpital Saint Louis, Paris. T) 33-1-42-49-43-07 E) francois.simon@sls.aphp.fr