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Meningitis Update from India Lacks H5N1 Bird Flu Data
Recombinomics Commentary
June 14, 2005
>> As of 8th June, 2005, the cumulative total is now 405 cases with 48 deaths (CFR=11.9 %). 314 cases discharged from hospital.
Control measures are underway including contact tracing, chemoprophylaxis of household contacts, and immunization of high risk groups. Serogroup A has been confirmed by the National Institute of Communicable Diseases (NICD). <<
The latest WHO update on meningitis in India continues to misstate the case fatality rate and provides no data on the H5N1 status of the cases.
The true case fatality rate based on outcomes (48 deaths and 314 discharges) is 13.3% which is virtually the same as the rate in the last update, 13.5% (37 deaths and 248 discharges). The WHO updates have listed CFRs of 11.9% and 10.1% respectively as well as a rate of 7.5% for cases through May 10. All of these calculations are incorrect because they assume that all hospitalized patients will recover, and there is no basis for such an assumption. Indeed, as some of the cases die, the improperly calculated rate rises because the proportion of the patients with an unknown outcome become less relative to the size of the population with know outcomes. Thus the early report significantly understated the true case fatality rate, while the most recent is less than 2% below the actual CFR.
Of more concern is the failure to report any H5N1 testing of these cases. Although an unreported number are positive for sero-type A, bacterial meningitis is a secondary infection of influenza. The initial reported cases were March 29 in New Delhi, which matches the time and location of bar headed geese migration from the northern plains of India to the Qinghai Lake Nature reserve. 150 bar headed geese were found dead on May 4 from H5N1 infections. Since these geese can fly from northern India to Qinghai Lake in 24 hours, it is likely that they were infected in India before arriving at Qinghai Lake.
The number of dead waterfowl, including bar headed geese continued to increase throughout the month of May, as did the number of meningitis cases. Earlier reports described H5N1 antibodies in Indian poultry workers even though India has never reported H5N1 infections in people or birds. The H5N1 in the bar headed geese is genetically similar to the Z genotype found in southeastern China, suggesting H5N1 is widespread in southern and eastern Asia, even though India and Bangladesh have declared themselves H5N1 free.
Clearly more surveillance and testing in India, Bangladesh, and China are necessary, as monitoring of H5N1 in Asia remains scandalously poor.
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