The Centre for Health Protection (CHP) of the Department of Health (DH) is today (February 7) closely monitoring an additional human case of avian influenza A(H7N9) in Jiangmen, Guangdong notified by the Health and Family Planning Commission of Guangdong Province (GDHFPC), and again urged the public to maintain strict personal, food and environmental hygiene both locally and during travel.
According to the GDHFPC, the patient is a 56-year-old man with underlying illness. He is currently hospitalised for treatment in critical condition.
To date, 562 human cases of avian influenza A(H7N9) have been reported by the Mainland health authorities, respectively in Zhejiang (156 cases), Guangdong (152 cases), Jiangsu (70 cases), Fujian (58 cases), Shanghai (44 cases), Hunan (24 cases), Anhui (17 cases), Xinjiang (10 cases), Jiangxi (nine cases), Shandong (six cases), Beijing (five cases), Henan (four cases), Guangxi (three cases), Jilin (two cases), Guizhou (one case) and Hebei (one case).
Despite the always helpful tally provided at the end of these HK CHP reports, the actual number of H7N9 cases in mainland China is unknown, and believed to be far higher.
We know that H7N9 can produce a broad spectrum of illness, ranging from mild (or even asymptomatic), to severe and life threatening. The result is, only those sick enough to be hospitalized, or monitored because they were a close contact of a hospitalized case, are likely to be tested for the virus.
We’ve seen estimates (see Lancet: Clinical Severity Of Human H7N9 Infection), that have suggested thousands (perhaps 10’s of thousands) of cases have gone undocumented, but the accuracy of these estimates is unknown.
There are also questions regarding this year’s reporting of cases. Since July of 2014, the Hong Kong’s Centre for Health Protection has incremented their totals by just 126 cases, with neighboring Guangdong Province responsible for more than 1/3rd of those cases (n=43).
Seven provinces (Hunan, Anhui, Henan, Guangxi, Jilin, Guizhou & Hebei) that reported cases during the first two H7N9 waves have yet to report a single case during this third wave, while several more (Shanghai, Zhejiang, Jiangsu, Fujian & Jiangxi) have so far reported substantially lower numbers this season.
Although closing of some live markets, and better disinfection protocols could account for this reporting decline, we’ve also seen evidence that some provinces simply aren’t reporting cases in `real time’, and instead are releasing `bulk’ announcements at irregular intervals (see HK CHP Notified Of 49 Recent H7N9 Cases In Mainland China).
Regrettably that, and the lack of patient details (age, gender, onset dates, etc.) have made it increasingly difficult to keep any reasonable track of this year’s epidemic.
Hopefully, between upcoming journal publications by Chinese scientists, and periodic updates from the World Health Organization, we’ll be able to make better sense of this third epidemic wave in the coming months.
Until then, we’ll simply have to accept that we may be seeing even less of the iceberg than usual.