Editors note: Amid fears over the rising number of human H7N9 cases in China, the World Health Organization Beijing Office answered some most frequently asked questions.

Q: Why is the number of human H7N9 cases rising?

A: This is wintertime. There are likely to be more flu cases than other seasons. An increase in H7N9 virus infections in humans has been noted since October, after a period of relatively few human cases over the summer, indicating that H7N9 infections may follow a similar seasonal pattern. This trend is expected to continue through the winter months.

Will the H7N9 virus continue to spread from the Chinese mainland?

Taiwan and Hong Kong have reported five human cases of H7N9 infection. The investigations indicated that these patients were likely infected on the Chinese mainland. So far, there is no indication of human-to-human transmission. The Chinese government continues to take effective surveillance and control measures.

Some research says H7N9 now has limited ability to be transmitted among humans due to genetic mutation. Is that true?

Since October, only one cluster was detected where human-to-human transmission might have occurred. It is possible that limited human-to-human transmission may occur, but there is no evidence of sustained or widespread human-to-human transmission. We continue to expect sporadic human cases.

Does this virus pose a pandemic threat?

For a human pandemic to occur, there needs to be sustained human-to-human transmission of the virus. An animal influenza virus that develops the ability to infect people could theoretically carry a risk of causing a pandemic. However, whether the avian influenza A (H7N9) virus could actually cause a pandemic is unknown.

Is it safe to eat chicken?

It's safe to eat well-cooked chicken. Evidence shows that avian flu viruses cannot live on in chicken that is properly cooked (to an internal temperature of 70 C).

Is it safe to visit live markets and farms in areas where human cases have been recorded?

It is best to avoid visiting live bird markets, but if this is inevitable, avoid direct contact with live animals and surfaces in contact with animals. If you live on a farm and raise animals for food, be sure to keep children away from sick and dead animals.