26 November 2006
New H5N1 Patients in China, Vietnam, Indonesia and Thailand as Winter Nears
The total number of WHO-laboratory confirmed cases of H5N1 infection has now reached 132 as four nations have had additional patients reported on the WHO website November 14-25. The cases fatality rate is 68/132 (52%).
China has now had three laboratory-confirmed patients, with two deaths. Two have occurred in Anhui province, in SE China, and one in Hunan province in southern China. On November 24th WHO reported the death of a 35-year-old farmer in Anhui province and announced that China has invited the WHO to join them in a joint mission to investigate H5N1 issues in Anhui province.
On November 25 the WHO reported the 93rd patient in Vietnam with H5N1 infection, of whom 42 have died. Notably, however, the case fatality rate has decreased to 33% (22 deaths/66 patients) since December 2004. During the preceding year, from December 2003, the case fatality rate had been 74% (20 deaths/27 patients). The average age of the patients in Vietnam increased in 2005 compared with 2004, according to Dr. Bui Ba Bong, Vice-Minister, Ministry of Agriculture and Rural Development, at the WHO conference on H5N1 held in Geneva November 7-9. He noted that the average age of fatal cases increased from 16.0 years in 2004 to 24.0 years in 2005. His presentation can be found on the WHO website, along with those from Kenya, China, Netherlands, Indonesia, and Japan.
Indonesia reported on 17 November new H5N1 infections in two women in Jakarta, 16 and 20 years old. The fulminant nature of this virus was reiterated by the fact that the 16 year old developed symptoms on 4 November, was hospitalized on 6 November, and died on 8 November. Similarly, the 20-year-old woman had symptom onset on 5 November, was hospitalized on 9 November, and died on 12 November. Clinical research studies are urgently needed to define better the pathogenesis of H5N1 influenza, and potential additional therapies, such as cytokine modulators and parenteral neuraminidase inhibitors.
Recent work implicating “cytokine storm” as a key cause of the rapid and severe illness due to H5N1 was strengthened by the publication this month online 11 November in Respiratory Research, a BioMed Central journal by M CW Chan and colleagues from Hong Kong and Hanoi, Vietnam (http://respiratory-research.com/content/6/1/135). They reported that H5N1 virus from both Vietnam in 2004 and Hong Kong in 1997 induced much higher amounts of proinflammatory cytokines and chemokines than did a comparison H1N1 influenza virus from human respiratory epithelial cells in vitro. These findings were similar to those reported from Hong Kong using human macrophages in vitro (Lancet 2002; 360:1831-1837). Therapeutic interventions designed to decrease inflammatory cytokines and chemokines would be important to test the proof-of-concept that hyperinduction of inflammatory cytokines contribute causally to the pathogenesis of H5N1 influenza disease and mortality.
Daniel R. Lucey, MD, MPH
Director, Center for Biologic Counterterrorism and Emerging Diseases
ER One Institutes, Washington Hospital Center
Co-Director, Master of Science Graduate Program in Biohazardous Threat Agents and
Emerging Infectious Diseases, Georgetown University Medical School
Washington, DC. Website: www.BePast.org