Via CIDRAP, Robert Roos writes: Study: H10N8 virus in first human case is novel strain. Click through for the full report and important links. Excerpt:
Chinese scientists reported today that the first human infection with an H10N8 avian influenza virus involved a new strain that carries genes from H9N2 viruses and has a mutation associated with adaptation to mammals.
Writing in The Lancet, the scientists detailed the results of their genomic analysis of the virus, which was isolated from a 73-year-old Chinese woman who died Dec 6. Her illness was the first known human case involving that strain.
A second human case in China was reported by the country's government news agency on Jan 27. "The pandemic potential of this novel virus should not be underestimated," the Lancet authors warn.
The study says the genes for all six of the virus's internal proteins were derived from H9N2 viruses, which circulate in poultry and occasionally infect humans in China, usually causing a mild illness.
The authors say H9N2 viruses also provided the internal protein genes for the H7N9 virus, which has caused scores of deaths in China since last spring, and the H5N1 virus, which has killed more than 380 people since 2003.
A rapidly fatal illness
The woman who had the first H10N8 infection lived in Nanchang, the capital of Jiangxi province (also the home of the second case-patient), and had hypertension, coronary heart disease, and myasthenia gravis, the report says. She fell ill with a cough on Nov 27 and became feverish 2 days later.
On Nov 30 she was hospitalized with fever and severe pneumonia. Despite antibiotic and antiviral treatment, mechanical ventilation, and other measures, she died 9 days after her first symptoms.
Using polymerase chain reaction and sequencing, the authors found that tracheal samples from the patient were positive for H10N8 and negative for seasonal flu viruses, H5N1, H7N9, and H9N2. They isolated the virus and dubbed it A/Jiangxi-Donghu/346/2013(H10N8), or JX346 for short.
An epidemiologic investigation revealed that the patient had visited a live-poultry market 4 days before she got sick and had bought a chicken but did not handle it, the report says. She had no other contact with live poultry and no contact with sick people in the 2 weeks before her illness, nor had she traveled recently. The virus was not found in samples from the poultry market.
Investigators identified 17 contacts of the patient, including 11 healthcare workers, 5 family members, and 1 caregiver, none of whom had any signs of flu-like illness in the 2 weeks after their exposures. Throat swabs from the healthcare workers tested negative for flu viruses, and serologic tests on the relatives were also negative.