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Case Fatality Rate of 82% for Mysterious Illness In Sichuan China
Recombinomics Commentary
July 26, 2005
According to an update by the SiChuan Ministry of Health (or their Provincial equilavent), as of 12pm 26th July, 117 cases have been reported in the Pigs-to-Human "Streptococcus" outbreak. This is a cumulative figure. Of these, 5 have been confirmed via laboratory tests, 71 clinically diagnosed and 41 suspected. Of these 117 cases, 5 have been discharged, 21 still remain in critical condition and 24 have died.
The above translation of the report of the Sichuan Ministry of Health indicates that the case fatality rate for the mystery disease is above 82%. There have been 29 outcomes, and 24 of the outcomes has been death. This does not include 14 suspect cases who died before being admitted to a hospital. A case fatality rate of 82% is very high and more like the H5N1 rate for Vietnam and Thailand or the rate of the cases described in an early boxun report on H5N1 deaths linked to the Qinghai Lake outbreak. Rates that high have also been described for Ebola and Marburg outbreaks in Africa.
Only 5 of the 117 cases have tested positive for the bacteria, which is a common bacteria in pigs. Normally the bacterial infection does not cause disease in pigs, but may cause problems when the pig is stressed or infected with another agent.
The high case fatality rate suggests the humans who disposed of the pigs were infected by the primary infection in the pig, not a secondary bacterial infection.
Although some boxun reports have suggested Ebola, the proximity of Sichuan Province next to Qinghai Province suggests H5N1 may be responsible. All of the H5N1 isolates from Qinghai Lake have the PB2 polymorphism, E627K, which has never been previously described in H5N1 isolated from birds. Passage of isolates from Hong Kong or imported duck meat through a mouse brain yield an isolate with E627K, and such isolates were found in tigers that died at a zoo in Thailand had neurological symptoms, which may be related to the meningitis seen in patients in Sichuan.
Thus, the sudden increase of 37 patients reported above, the widespread distribution of cases in at least 75 villages, the high case fatality rate, and the neurotropism, all point toward H5N1 involvement in the expanding outbreak.
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