The number of confirmed cases of new A/H1N1 swine flu in Japan surged over the weekend, when health officials reported earlier today, Monday, that at least 121 people have tested positive, said a report in the Associated Press (AP). This compares with only 4 confirmed cases on Friday.

The Japanese government has closed hundreds of schools and ordered the cancellation of many public events in an effort to contain the spread, which appears mostly to affect teenagers. A bank in southwest Japan has also asked its staff to work from home for now after an employee tested positive, said the AP report.

Health officials in the hardest hit areas, thought to be mostly in the Hyogo and Osaka prefectures, said that most of the patients were recovering either in local hospitals or at home.

According to a BBC news report, over the weekend the Japanese authorities also reported the country’s first case of community spread swine flu in a patient from the large port city of Kobe (the capital of Hyogo prefecture), which is about 270 miles (430 km) west of Tokyo.

The patient, a 17-year old student, had not travelled abroad, raising speculation that if more cases like this emerge it will cause the World Health Organization (WHO) to raise the pandemic alert to phase 6, signifying that more than one WHO region now has cases arising from within communities as opposed to travellers bringing it in from infected areas. Currently only North America is in that category.

The WHO pandemic alert level is not an indicator of how lethal the virus is, only how it is spreading.

Japanese Prime Minister Taro Aso said although everyone had to be careful “we must respond calmly and appropriately,” and that “with quick treatment patients can recover”.

Meanwhile hospitals in Japan have organized special “fever clinics” just for swine flu patients, local media are carrying picture guides on hand and mouth hygiene, and local authorities have set up hot lines giving people advice on what to do if they have flu symptoms.

Many employees in shops and railway stations in the areas most affected are now wearing masks, some because they have instructed to do so by their employers, said a report in the Japan Times.

In Osaka, people appeared concerned rather than panicked, although several told the newspaper that they were planning to stay at home this week, and would keep their children away from school, even though they don’t live in the affected areas.

One Osaka resident, 33-year old Ayako Ito said there was no sense in taking a chance and that:

“I think my child can afford to miss a day or two of school, although I hope it’s not for too long.”

However, BBC reporter Roland Buerk in Tokyo suggested that because of its aging population, Japan is particularly anxious about flu.

But it appears from the reports so far that most of the new cases in Japan are occurring in children and young adults. This is in line with the clinical characterization announced by the WHO in a press briefing last week.

Dr Nikki Shindo, Medical Officer, for the World Health Organization (WHO) Global Influenza Programme said last Tuesday that so far it appeared that the people most susceptible to the novel H1N1 virus were in one of two groups.

One group is people with existing underlying medical conditions and the other group is previously healthy and fit young children and adults.

The latest official figures from the WHO show that 39 countries have confirmed at least 8,480 human cases of new A/H1N1, most of them in the United States and Mexico, including 72 deaths.

Turkey, India and Chile joined the list of countries reporting swine flu cases over the weekend.

Sources: AFP, AP, BBC, WHO, Japan Times Online.

Written by: Catharine Paddock, PhD