Patients at risk should seek immediate medical attention :

Influenza A - fast spreading but less dangerous

By Dhaneshi Yatawara

Dr. Jude Jayamaha	Dr. Ananda Wijewickrama

The panic among the people is creating more danger than infection by the Influenza A virus. The Health Ministry has already made arrangements to prevent the spread of the disease. Last week the Ministry advised the public to take precautionary measures to prevent the spread of Influenza A and rush patients in the risk category to hospitals if symptoms do not fade away in a day or two. The health officials have identified risk groups as expectant mothers, those over 65 years of age, children less than two years and those with non-communicable diseases such as diabetes, kidney failure and coronary heart diseases as most vulnerable.

Although the country is getting ready for a major disaster according to medical experts, the fast spreading illness is not fatal. Special concern is necessary for those in the risk groups, but the disease is highly treatable.

Common flu

"Influenza A has been in Sri Lanka for a long time. It only produces a normal cough and cold and sometimes fever. It is not a dangerous illness," said Dr. Ananda Wijewickrama, Infectious Diseases Physician of the Infectious Diseases Hospital, Angoda.

"But this influenza virus can change its structure. Some of the viruses formed after the changes could be dangerous. Over the years there have been several large outbreaks due to the dangerous changed viruses, but they lasted a short period. The Influenza has persisted for a long time," Dr. Wijewickrama added.

Not all types of flu are the same. Some types can make you very ill while others could cause mild symptoms. Different strains of the flu virus mutate over time and replace the older strains of the virus.

"From time to time we treat patients with Influenza A but recently the numbers have gone up, probably because we are more vigilant and identify cases. Most patients seeking treatment need not be admitted," said Dr. Wijewickrama.

Dr. Wijewickrama said the current Influenza A is not dangerous and is just another flu with a fever, running nose, slight breathing difficulties and cough. In many people without any treatment the illness naturally wears off. "But for a category of patients it can be dangerous, especially pregnant women and people with other lung diseases such as chronic bronchitis and heavy smokers. Heavy smokers are in danger as their lungs are damaged due to smoking," he said.

"Normally, we do not treat patients with a common flu as it's a viral infection and the patient with his or her own immunity should recover. But in risk categories such as pregnant women and people with lung diseases, it could lead to serious complications, especially pneumonia. They are being treated," he said.

Prevent spreading

People should take general precautions to prevent the illness spreading, said Dr. Wijewickrama explaining the precautionary methods. "It spreads by droplets when a person sneezes or coughs. But the virus cannot travel a long distance in the air - only about a metre. Therefore, people in close contact with a patient only are likely to be affected. So, it is best to use a handkerchief or a tissue when coughing or sneezing," he said. Washing hands frequently will also help to reduce the spreading of the virus. A patient can wear a mask when in public places. "For any viral infections it's best to have a good physical rest. But if one needs to go to work or attend to some other matter and the patient feels fit then there is no harm. But he or she should take precautions to avoid spreading the virus as much as possible," he said.

If a patient finds that conditions do not improve even after three or four days he should seek medical treatment as he may risk a secondary infection even if not in the risk category, Dr. Wijewickrama said.

We have heard of influenza viruses under different names at different times. The prominent ones, for example are the commonly known 'swine' flu and the 'H1N1' flu.

"The difference between birdflu and H1N1 is that it's more dangerous. But birdflu transmission to man is very limited. Comparatively H1N1 is very much less dangerous but more infectious - i.e. transmits very quickly from man to man," Dr. Wijewickrama said.

"Initially, the illness became prominent in 1999 and was transmitted by people visiting from abroad. During that time we tried to delay the spread of the virus by keeping the patients isolated in hospital, until they complete the course of treatment. But eventually it spread to the community. Yet, some who returned from abroad were asymptomatic and showed no reason for us to keep them in isolation. Thus it is difficult to prevent the illnesses spreading completely," he said.

Influenza A variants are sometimes named according to the host or carrier species in which the strain is endemic or to which it is adapted. Thus several main variants have been named in the world so far - i.e. Bird flu, Human flu, Swine influenza, Equine influenza and Canine influenza.

Total alert

According to the National Influenza Centre the current flu is mainly caused by Influenza A and B viruses. "Influenza viruses are categorised into three, out of which Influenza A and B cause disease mainly to humans ," said Dr. Jude Jayamaha, Consultant Virologist, National Influenza Centre, Medical Research Institute. He said Influenza A is again divided into categories according to their protein structure. It is based on the protein structure named haemagglutinin and the enzyme in it called neuraminidase is also considered in categorising different variants of viruses.

"We classify them according to the composition of the two protein and sugar molecules. For instance, we can classify them as H1N1,H3N2 and H2N2 as viruses that cause influenza in humans. Influenza B is not classified as such," Dr. Jayamaha said.

In this century Influenza A has caused pandemics. Pandemic means disease spreading from one continent to another. The most famous pandemic was the 1917 - 1918 Spanish flu. Very recently there was one in 2009. "As a result virologists, clinicians and scientists are keen on doing research on these viruses. And Influenza A has a remarkable ability to change its antigenic surface.

It can change its composition that the current population may not be immune. Thus the virus can cause an epidemic or perhaps a pandemic within a short time, for example, one to two months," he said.

"Influenza A can infect different varieties of animals. Mainly avian species (birds) - such as ducks, fowls and migratory birds. Birds travelling long distances can actually transmit infection to other continents too. The other type of animal is the pig. As a result it can also change its structure in these animals and infect humans. It does not happen frequently," he said.

The so called 'Bird' flu was a natural as well as a lethal infection in birds. Humans too can occasionally get infected, according to Dr. Jayamaha. "A human would not he infected simply by visiting a poultry farm. But close and constant contact with the birds could give high probability to get infected," he said.

"Influenza A predominantly causes flu like symptoms in Sri Lanka. Influenza B is also present. Previously Influenza B was not so prominent," Dr. Jayamaha said.

Diagnostic facility

"We have a good diagnostic facility and a surveillance facility. It's a very active surveillance - going in to OPDs of hospitals as well and not only to wards. From 19 hospitals we have taken samples throughout the year for the past four years - from the OPD patients as well as severe accute patients. We take 200 - 300 samples, and even send them to the World Health Organization Reference Laboratory in Melbourne, Australia to identify whether they are compatible with the vaccine strains," he said. Dr. Jayamaha said according to the statistics collected by the National Influenza centre the number of cases seem to be static though it increased in April.

The National Influenza Centre carries out research and surveillance programs of the influenza illnesses prevailing in Sri Lanka with state-of-the-art technology.

"We are doing numerous programs with local expertise and with the assistance of a world renowned expert, Professor Malik Peiris from the University of Hong Kong," said Dr. Jayamaha. " We have a state-of-the-art respiratory reference laboratory established in 2002 due to the untiring efforts of Dr. Geethani Wickramasinghe who was formerly in charge of the National Influenza Centre," Dr. Jayamaha said.

The respiratory reference laboratory conducts the most accurate test to identify Influenza viruses, even world-class labs use, the rt-PCR test (Realtime polymerase chain reaction test) on suspected flu patients. "The test costs around Rs. 10,000 per test. So, for the test alone the Government spends quite an amount. We also do DFT -the direct fluroscent test - which is also a high tech test used in modern science," said Dr. Jayamaha.