Three Reported Asymptomatic Thai Binh Bird Flu Patients
Recombinomics Commentary
March 9, 2005
>> Vietnamese health officials said Wednesday the 61-year-old widow of a bird flu victim has also tested positive for the H5N1 virus, but showed no symptoms.
Earlier in the day, officials reported that an 80-year-old man - who had two infected grandchildren - also had the virus but did not fall ill.
The two cases raised concerns that avian influenza may be more widespread than originally believed. <<
The two asymptomatic H5N1 positive patients in Thai Binh raise the number of reported clusters with a reported asymptomatic case to three. The youngest brother of the January familial cluster was also reported to have been positive for H5N1, although he also did not have symptoms.
Detecting H5N1 in three family members of the Thai Binh cluster is clearly cause for concern. Although similar patients have not been reported in the south, the assays at the Pasteur Institute have had sensitivity problems and were creating false negatives in patients who had symptoms but survived. These patients had atypical symptoms and epidemiological histories, strongly suggesting that they too were infected via human-to-human transmission.
The false negatives in atypical cases in the south coupled with asymptomatic family members of confirmed H5N1 fatal cases in the north, indicates that H5N1 can produce a wide range of symptoms in humans and has achieved efficient transmission.
The poor surveillance precludes definitive answers on the extent of the spread, but it is clearly well above previously reported levels and has probably spread beyond the borders of Vietnam and Thailand. The cases in Cambodia have also been described as complex, hinting at further unreported spread.
These reports highlight the poor monitoring of H5N1 and expose the folly of trying to control a virus that is silently spreading throughout the region. A massive screening effort is long overdue and is probably too late to control H5N1 in humans. The virus that was detected in January, 2004 in human-to-human transmissions in Thai Binh has clearly continued to infect additional patients.
The failed monitoring and control of H5N1 in southeast Asia is well beyond scandalous.
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