A flu for all seasons

By DR ONG CHUN CHIANG

Seasonal flu is very common around this time of the year when the inter-monsoon weather changes rapidly. Seasonal flu is caused by the influenza virus, the main ones being Influenza A (H1N1 and H3N2) and Influenza B viruses.

Seasonal flu that commonly afflicts Europeans and North Americans every winter can be traced to East Asia and South-East Asia. Malaysia is one of the countries listed as a point of origin of seasonal flu. The problem with these viruses is their ability to mutate as they travel around the globe. This gives rise to new strains every year. Vaccines produced by scientists against these have to be revised yearly.

The latest flu outbreak that started in Mexico is spread by an influenza virus from the Orthomyxoviridae family. It is endemic in swine populations. Known strains of “swine” influenza viruses are classified as either Influenza C or one of the subtypes of Influenza A. These strains can mutate into a form that can pass from human to human.

There have been many outbreaks of “swine” flu in the past. The 1918 flu pandemic that took the lives of millions of people worldwide was associated with a H1N1 virus that was transmitted from swine to humans or from humans to swine. There is insufficient data from then to provide us with detailed information.

Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam. These pigs can carry human influenza virus, which can combine with H5N1 (bird flu virus), passing genes between to mutate into a form that can pass easily among humans.

According to the US Centers for Disease Control and Prevention (CDC), A/H1N1 flu symptoms are similar to those of influenza and influenza-like illnesses. Symptoms include runny nose, sore throat, cough, fever, body aches, headache, chills, and fatigue. Some patients also report having diarrhoea and vomiting.

As these symptoms are so common and general, the patient’s contact history is of paramount importance. Patients with the above symptoms who have travelled to Mexico, the US or other endemic areas over the past seven days must be tested for A/H1N1 flu. Confirmation of this requires laboratory testing of a simple nose and throat swab. However, conclusive results may take some time.

The CDC reports that the transmission of A/H1N1 flu among humans is very much like that of seasonal flu. It is believed to spread through coughing or sneezing of infected people and touching something with the virus on it before touching your own nose or mouth.

The virus is not transmitted through food as it is destroyed by simple cooking. A/H1N1 flu in humans is most contagious during the first five days of illness and can remain contagious for up to 10 days. It can be treated using two drugs licensed in the US, namely oseltamivir and zanamivir. It is recommended that confirmed cases be treated under strict medical supervision.

The vaccine for human seasonal H1N1 flu does not protect against the “swine” A/H1N1 flu as they are antigenically different. Prevention of spread of A/H1N1 flu is the same as prevention against other influenza virus. This includes frequent handwashing with soap and water or with hand sanitizers. You should avoid touching your mouth, nose or eyes with your hands unless you have washed them. If you cough, cough into a tissue and throw away immediately, or cough into your elbow or hand, then wash them immediately.

The Malaysian government is taking the threat of A/H1N1 flu very seriously. As reported in the media, Asian countries are more prepared this time round. All necessary precautionary facilities from the recent SARS outbreak are still in place. These have been activated to prevent the spread of A/H1N1 flu. Already, people arriving from endemic countries are being medically screened.

Unfortunately, some travellers may be inconvenienced by delays and confinement but these steps are essential. The Health Ministry has advised Malaysians against travelling to endemic countries, especially Mexico and the US, unless travel is of utmost necessity. Travellers should take every precaution so as not to be exposed to the A/H1N1 flu virus.

Medical personnel play very important roles in times like these. Any patient who presents with flu-like symptoms and has been to endemic areas over the past one week or so should be tested for A/H1N1 flu. If the suspicion is high, the Health Ministry should be informed so that the patient receives urgent treatment while awaiting test results.

We all have a duty to act sensibly to prevent another worrying flu pandemic. There is no reason to panic as this virus has yet to be reported in Malaysia, but every precaution should be taken to prevent it from entering our country.

- THE STAR