A 4-year-old boy in China’s Henan province has become the first human case of H3N8 bird flu.
Earlier this week, the National Health Commission (NHC) in China reported the case of a 4-year-old boy who had developed fever and other symptoms. Due to worsening symptoms, the child was later shifted to a local medical institution. Further investigations and sampling tests revealed the presence of the H3N8 bird flu virus. According to the report, the child raised chickens and had close exposure to wild ducks and other domesticated animals.
This is not the first time that rare bird flu strains have emerged in China. Last year, the country reported the first human case of H10N3 bird flu. This particular strain is extremely rare and is not associated with causing severe disease in poultry. Therefore, it is unclear how the 41-year-old contracted the infection. Moreover, health experts did not find any evidence of human-to-human transmission. The man was later discharged, and contract tracing did not reveal any further cases.
Although the H3N8 strain has been detected in animals such as birds, dogs, horses, and seals before, this is the first human case of the bird flu strain. Whole-genome sequencing of the child’s samples revealed genes from viruses previously detected in wild birds and poultry. Thus, suggesting that the strain resulted from a reassortment of viruses. Health officials are warning people to avoid direct contact with poultry and to practise good hygiene when cooking food.
Risk of Large-Scale Outbreak Remains Low
Influenza viruses cause infections in both humans and animals. Close contact with animals often causes these viruses to jump from one species to another. Animals such as pigs serve as a ‘mixing vessel’, allowing for human, avian, and swine flu viruses to mix and create a new strain. Moreover, infections in humans can also result in mutations that make it easier for viruses to spread. Therefore, scientists worry about a possible spillover event occurring in the future.
Scientists claim that the H3N8 strain is also responsible for the 1889 influenza pandemic, also called ‘Russian flu’. Thus, raising concerns over the risk of the virus. However, in the past, there have been multiple cases of a single case appearing in humans and not spreading any further. Experts at the NHC have called it a case of an occasional bird-to-human cross-species transmission. Moreover, health officials did not report any symptoms in the boy’s close contacts. They, therefore, believe that the risk of a large-scale human outbreak is low.
The incidence of human bird flu cases has significantly increased over the year. In February of last year, Russia reported multiple cases of the H5N8 bird flu strain. All cases occurred among poultry farm workers who likely got exposed during an outbreak at the poultry plant. Moreover, none of the individuals developed any symptoms. Nor did the researchers detect any risk of human-to-human transmission.
More recently, the UK reported its first human case of the rare H5N1 strain. This particular strain is responsible for large poultry outbreaks and human infections across the world. Due to the increase in cases, infectious disease experts have called for increased surveillance of these strains.
CDC Confirms Bird Flu in Colorado Man
In a statement on Thursday, the US Center for Disease Control and Prevention (CDC) confirmed the detection of the H5 influenza virus in Colorado man. This is the country’s first human case of H5 bird flu. Although health officials did not specify the neuraminidase subtype of the virus (N portion of an influenza A virus’ name), it is most likely that the man was infected with the H5N1 strain.
According to the statement, the man is an inmate at a state correctional facility and was working on a farm as part of a pre-release employment program. He was working with infected poultry at the farm and ultimately contracted the infection then. However, he largely remained asymptomatic, except for the complaint of fatigue. The man is currently under isolation and is receiving treatment with the antiviral oseltamivir.
The Colorado Department of Public Health and Environment has stated that there are currently no other human cases of the H5 virus in the state or country. According to the CDC, this single case does not pose a risk to public health. However, they are taking precautions and implementing preventative measures to reduce the risk of infection. Poultry farm workers are advised to avoid contact with ill or dead poultry, and any surfaces possibly contaminated with faeces from wild or domestic birds. However, eating properly handled and cooked poultry remains to be safe.