Recombinomics: Human to Human H5N1 Transmission in Hunan China

Commentary

Human to Human H5N1 Transmission in Hunan China
Recombinomics Commentary 07:53
January 21, 2009

The health ministry said it was unable to do tests to confirm whether the mother had died of avian influenza, as no samples were collected when she passed away.

But it added it was unlikely the girl caught bird flu from her mother.

"We cannot be sure that the patient's mother had bird flu, and investigations show the patient had been exposed to live poultry markets," the statement said.

"Therefore, we believe the patient's infection most likely came from a live poultry market or another unknown exposure."

The above “beliefs” offered by the Ministry of Health in China on the human to human (H2H) transmission of H5N1 in Hunan have no scientific basis, yet these “beliefs” have been repeated constantly since H5N1 in humans spread out of China in late 2003 into northern Vietnam.

H5N1 infections of humans from poultry remain rare, so the likelihood that the mother and daughter were infected by poultry through independent events 5-10 days apart is remote. The likelihood that the mother infected her daughter however, is much higher, which has been supported by the large number of familial clusters linked to H5N1 which have 5-10 day gaps in disease onset dates.

These clusters are not surprising and the transmission in Hunan follows the typical pattern. The index case is initially treated at home, which is a high risk activity. Family members usually have no training in universal precautions, or infectious disease control, and have no protective equipment. Moreover, they have read media reports which cite official comments such as those above which claim that family members are not infected by close contacts, which cite “beliefs” which have no scientific basis.

As an infection progresses, the H5N1 viral load rises, and the likelihood of infection by a family member also increases. Family members typically develop symptoms within a day or two of the death of the index case.

The Hunan H2H transmission is supported by disease onset dates. The index case developed symptoms in late December, and died on January 6 or 7. Her daughter developed symptoms on January 7, as indicated in the WHO update, which fails to mention the pneumonia death of the mother.

This cluster also includes the common failure to collect a sample from the index case. As a result, the number of “confirmed” cases is one, there is no confirmed cluster, and the suspect case is ignored in the WHO situation update.

This scenario has been repeated dozens of times in high profile clusters, such as the first confirmed cases in Indonesia, China, or Cambodia. The same is true for large clusters in Indonesia (Karo and Garut) or Pakistan. Indonesia also eliminates official clusters by misdiagnosing the index case with lung inflammation, dengue, or typhus. Additional clusters are eliminated through use of an insensitive “rapid test” or testing of samples collected after Tamiflu treatment has reduced the viral load.

These activities by official agencies have greatly reduced the number of confirmed clusters, which have been large and obvious since 2004.

The scientific analysis of the cluster in Hunan strongly suggests the index case infected her daughter, who was H5N1 confirmed. The status of two additional family members, who were reported to be hospitalized in Shanxi, remains unclear, but the H2H transmission in Hunan is not.
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