Recombinomics Commentary 13:23
March 21, 2009

According to report of Hospital Bac Lieu am 20 / 3, patients Ly Thi Hang, 26 years old, living at 23 Hamlet, Chau Hung Commune, Thanh Tri district, Soc Trang, have died of infection by the H5N1 virus.

The above translation describes another suspect H5N1 fatality in southern Vietnam. This case is about 35 miles south of the two earlier cases in Dong Thap (see updated map). In Dong Thap, the initial case (3M from Phu Hoa Hamlet in Chau Thanh district) died March 19 and was H5N1 lab confirmed. The second case (4F) was from an adjacent hamlet (An Hoa hamlet in Chau Thanh district) and is recovering. This case has tested negative.

However, the case fatality rate in Vietnam is high, raising concerns that milder cases are testing negative. The other two cases in the south have died, as have three of four confirmed cases in northern Vietnam. However, the only reported survivor in northern Vietnam was the sister of a fatal case (13F) who was not tested. The surviving sister (8F) initially tested negative on the rapid test, but was subsequently PCR confirmed twice, meeting the WHO definition of an H5N1 confirmed test. However, local media reports indicated the lab confirmation was inconclusive, citing the negative rapid test, and the attending physician tried to justify the lack of testing of the fatal case, even after the sister was twice PCR confirmed. The comments regarding this cluster in the north raise questions about testing and reporting of H5N1 cases in Vietnam in general.

Previous, in the spring of 2005, northern Vietnam had an increase in the number of clusters and a dramatic drop in the number of fatal cases (less than 10% CFR). Similar mild cases have been reported in Egypt in the spring of 2007, and this year all 8 confirmed cases in Egypt have been discharged or stable. The most recent confirmed case in Egypt was symptomatic for 4 days, raising concerns that the number of mild cases in Egypt this year is markedly higher than the 8 confirmed cases, since most suspect cases without a link to dead or dying poultry are not tested fro H5N1, and milder cases would commonly be diagnosed as seasonal flu.

In Vietnam, the current cluster of three cases in the south are the first reported this year, and last year the vast majority of confirmed cases were also in the north. These recent cases in the south raise additional concerns of unreported milder cases in Vietnam, as well as other countries which report high case fatality rates, such as Indonesia and China.