Apr 14, 2013 (CIDRAP News) – In quickly evolving H7N9 influenza developments, the virus has spread to a new part of China—as two illnesses were reported today in Henan province—and Beijing officials have reported the outbreak's first asymptomatic case.

Meanwhile, the H7N9 hot spot in the eastern part of the country reported 9 more cases, spiking the case count to 61, according to official sources and media reports. Shanghai also reported 2 deaths of previously announced cases, which pushes the fatality total to 13.

The asymptomatic case is in a child who apparently tested positive during risk-group surveillance.

The cases from Henan were included in an update today from the World Health Organization (WHO), which did not include the 10 new cases outside of Henan. Confirmation of the virus for the first time in central China comes just 1 day after the first H7N9 case was detected outside of eastern China, in a 7-year-old daughter of Beijing poultry traders.

All of China's provinces are now able to test for the virus, according to earlier media reports.

Henan province is about 590 miles northwest of Shanghai and about 440 miles south and slightly west of Beijing.

Case total soars to 61 infections, 13 deaths

One of the Henan province patients is a 34-year-old man who got sick on Apr 6 and the other is a 65-year-old man who got sick on Apr 8, according to the WHO.

Xinhua, China's state news agency, had a few other details today about the two patients. It said the younger man works as a chef in Kaifeng and is in critical condition and the older man is a farmer from Zhoukou who had frequent contact with poultry in his home and is also in critical condition. The towns are about 60 miles apart.

Meanwhile, Jiangsu province, Zhejiang province, and Shanghai today announced nine more H7N9 infections between them, according to a separate report from Xinhua. Jiangsu reported two cases, in 50-year-old and 26-year-old men. Three new case-patients from Shanghai were men, ages 54, 73, and 78. Zhejiang reported four cases, two women ages 62 and 64 and two men ages 75 and 79.

A statement today from Hong Kong's Centre for Health Protection (CHP), which cited mainland officials, said all 11 of the newly reported patients (excluding the asymptomatic child) are hospitalized.

The two newly reported deaths were in Shanghai patients whose illnesses were announced earlier. One is a 67-year-old woman who died last night and the other is a 77-year-old man who died this morning, according to Xinhua, which cited the Shanghai Municipal Health and Family Planning Commission.

Early details of first asymptomatic case

An announcement of the asymptomatic case was posted a few hours ago on the Beijing health department Web site and was picked up and machine-translated by Crawford Kilian on his H5N1 infectious disease news blog. Contributors at the FluTrackers infectious disease Web message board quickly followed with other reports that confirmed much of the information in the translation.

According to the reports, the case involves a 4-year-old Beijing boy. The health department notice suggests that he has no clinical symptoms and was tested during surveillance of high-risk groups. The boy has reportedly been hospitalized for close observation.

The boy's father or a neighbor bought chickens from the father of the first confirmed Beijing case-patient, the 7-year-old girl whose illness was announced yesterday, according to various translations, including one by a former resident of China who translated the health department report for CIDRAP News. The boy's parents apparently trade poultry and fish in the same village as the girl's parents do.

Emergence of an asymptomatic H7N9 case, if confirmed by other official sources, would be a significant development. Though a few cases have been mild, most of them have involved severe lower respiratory infections. Flu experts have said it's unclear if cases so far represent the tip of the iceberg of a broader clinical spectrum or if the virus mainly causes a more severe illness pattern.

The WHO said investigations are still under way into the source and reservoir of the H7N9 virus. Until those are identified, the group said it expects more human cases to be reported from China.

So far there is no evidence of ongoing human-to-human spread, the WHO said.

The US Centers for Disease Control and Prevention (CDC) said recently that it's likely some limited human-to-human spread would occur in China's outbreak, a pattern seen with other viruses, such as several instances of limited transmission with H5N1.

International flu experts headed to China

In other developments today, four international influenza experts have been invited to China to help the country respond to the H7N9 outbreak, according to a report from Bloomberg News today, which cited unidentified sources who are familiar with the situation.

Bloomberg said the experts are Nancy Cox, PhD, director of the CDC's Influenza Division; Anne Kelso, PhD, director of the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne; Angus Nicoll, MB, CBE, who head the European Centre for Disease Prevention and Control Influenza and Other Respiratory Viruses Programme; and Malik Peiris, PhD, a noted microbiologist at the University of Hong Kong.

See also:

Apr 14 WHO update

Apr 14 Xinhua story on Henan cases

Apr 14 Xinhua story on 60 confirmed cases

Apr 14 CHP statement

Apr 14 H5N1 Blog post

Flutrackers thread

Apr 14 Bloomberg News story