China today reported four new H7N9 infections, one fatal, including the first case from Jilin province, which lies well north of the main outbreak area.
Three of the latest illnesses are from Guangdong province, a hotspot of disease activity during the outbreak's second wave. Patients include a 46-year-old woman and a 69-year-old man, both of whom are hospitalized, and a 64-year-old man who died from his infection, according to a provincial health ministry statement translated and posted by FluTrackers, an infectious disease news message board.
The patient from Jilin province is a 50-year-old poultry farmer in the capital city of Changchun, according to a news report today in Chinese from Xinhua, China's state news agency, that was translated and posted by FluTrackers. He is reportedly hospitalized in stable condition.
Jilin province, located in northeastern China, borders North Korea and Russia. The area where the H7N9 case was detected is about 600 miles northeast of Beijing, the northernmost site where H7N9 cases have previously been detected. So today's news of a case in Jilin represents an expansion of the outbreak area.
The four new cases boost the outbreak total to 365, according to a case list kept by Flu Trackers. The latest death lifts the unofficial number of fatalities to 113.
Over the past several days the second wave of infections has tapered off, after exceeding the last spring's first wave. So far 229 H7N9 infections have been reported in the second wave, compared with 136 during the first.
Researchers detail father-son case cluster
In other developments today, researchers from China reported on a family case cluster in Shandong province that occurred last April during the outbreak's first wave. The team reported its findings in the latest online edition of BMC Infectious Diseases.
The two sick family members were a 36-year-old father and his 4-year-old son. The man got sick first and was hospitalized with acute respiratory distress on Apr 21, followed by his son's hospitalization a week later. Samples from both patients were positive for H7N9, and a genetic analysis found that the viruses were almost identical.
An investigation into the sources of their illnesses found that the boy had significant unprotected exposure to his father while he was sick and that the two had not had contact with poultry, but had been near a poultry environment.
The family lived in a rural-urban area of Zaozhaung, a city of 3.7 million in southern Shandong, near the border with Jiangsu province. Several live poultry in cages were located 10 meters (33 feet) from the family's apartment, and two live poultry slaughtering sites were housed about a third of a mile and about two thirds of a mile from their neighborhood.
Two days before the father got sick, he had visited a village that had several large poultry farms, but he didn't enter them. None of the family members had bought poultry at the local slaughter sites or had contact with any sick or dead poultry,
Follow-up of 11 close contacts found no other H7N9 infections. Health officials collected 96 environmental samples, and only one yielded the virus: a swab taken from a chopping block at a live poultry market about 6 miles from where the family lived.
Researchers concluded that the father's infection probably resulted from contact with a contaminated environment and that the son was likely infected during prolonged unprotected exposure to his sick father, but they added that the environment or other sources can't be excluded.
The case fits with a risk assessment from the World Health Organization (WHO) that says the virus doesn't transmit easily from human to human, but human-to-human transmission may have occurred when there was close unprotected contact with sick patients.
Feb 21 FluTrackers thread
FluTrackers human H7N9 case count
Feb 21 BMC Infect Dis abstract
Jan 21 WHO H7N9 risk assessment