There is no ‘swine flu’ influenza virus in the country as the World Health Organisation (WHO) declared the virus as seasonal influenza in 2011 after the 2009 flu pandemic.
Officials of the Institute of Epidemiology, Disease Control and Research (IEDCR), which monitors the seasonal influenza, avian and other influenza viruses in Bangladesh, said this at a press briefing in the city on Sunday.
The IEDCR held the emergency press briefing on 'Influenza A/H1N1', known as swine flu virus, to clarify media reports that the some swine flu cases were found in recent times.
The officials said they wanted to dispel misconceptions about seasonal influenza viruses as the media have been publishing misleading news.
Swine flu hit the headlines recently after former MP from reserved seat Fazilatunnesa Bappy died of respiratory tract infection caused by H1N1 virus at Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital.
The BSMMU wrongly interpreted the H1N1 influenza virus as swine and avian flu virus, said the officials.
IEDCR director Meerjady Sabrina Flora gave a presentation on the swine flu facts at the press briefing attended by Director General of the Directorate General of Health Services (DGHS) Dr Abul Kalam Azad and principal scientific officer Dr ASM Alamgir.
In her presentation, Dr Flora said no swine flu virus now attack humans in the world. Seasonal influenza, a common respiratory tract infection that affect human, is caused by common viruses (Influenza A/H3N2, Influenza A/H1N1pdm2009, Influenza B) while avian influenza/bird flu is caused by avian influenza viruses (AI/H5N1, AI/H7N9, AI/H9N2 and A/H5N6).
The 2009 pandemic A/H1N1 virus has become a seasonal virus, continuing to circulate with other seasonal viruses since August 2010 when WHO declared the end of the H1N1 pandemic, she added.
Dr Flora said in the USA, 40 per cent of cough and cold is caused by H1N1 virus while it is 15 per cent in Europe. In Bangladesh, cough and cold is caused by H3N2 virus and the peak season for H1N1 virus infection is from April to September, not winter like in the USA and Europe.
But the virus is now pandemic, meaning it is available all the time, she added.
Seasonal influenza viruses may cause complications to people with asthma/COP, diabetes, heart disease and those who have had a stroke, elderly people aged 65 or over, pregnant women, HIV or AIDS positive people, cancer patients and children under five, especially those under two, she explained.
She said seasonal human influenza viruses spread from person to person primarily through large-particle respiratory droplet transmission (e.g., when an infected person coughs or sneezes near a susceptible person).
Transmission via large-particle droplets requires close contact between source and recipient persons, because droplets do not remain suspended in the air and generally travel only a short distance (less than 1.0 metre) through the air, she added.
She also mentioned that contact with respiratory-droplet contaminated surfaces is another possible source of transmission. All respiratory secretions and bodily fluids (diarrheal stool) of seasonal influenza cases should be considered potentially infectious.
The estimated incubation period is unknown and could range between one to seven days, and more likely two to five days at 25 degree to 39 degree centigrade temperature, she said.
About symptoms, Dr Flora said people who have the flu often feel fever or feeling feverish/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches and fatigue. Some people may also throw up and have diarrhoea.
She also said flu vaccination can help protect people who are at greater risk of getting seriously ill from flu.
Vaccine is recommended only for people with high risk. Immunity due to vaccine lasts for one year and the best result of vaccine is ensured if it is taken by February, she added.