The whole world is worried about outbreaks of bird flu?

Although the influenza A virus in poultry is not usually infectious to humans, there have been many cases of human infection with bird flu since 1997; These cases are often caused by direct contact with infected poultry or contaminated surfaces (ground, water).

Conditions for outbreaks of avian influenza

H5N1 virus

There is much uncertainty about the effects of subtypes and avian influenza virus strains on humans, for example, low-pathogenic viral strains and high pathogenicity that have had different effects on human health

Because of the great potential of human infection, health authorities must closely monitor the outbreak of avian influenza in humans. Humans infected with Avian Influenza have been detected since 1997 but no human-to-human transmission has occurred; however, because influenza A virus has the potential to easily change and spread, monitoring of infection patterns among humans becomes very important.

So far, the transmission of H5N1 virus from human to human remains rare and has not exceeded 1 person. Scientists fear that the H5N1 virus could one day spread and spread easily from person to person, with little or no antibodies to protect, then the pandemic will flare up.

Summary of cases of human influenza infection

Cases identified as avian influenza viruses have infected humans since 1997:

- In 1997, in Hong Kong Special Administrative Region, influenza A H5N1 virus infected both poultry and humans. This is the first case where influenza A virus is seen directly from birds to humans.

In this outbreak, 18 people were hospitalized and 6 died. To control the outbreak, Hong Kong authorities destroyed about 1.5 million chickens to eliminate the disease. Scientists have confirmed that the spread of the virus is mainly from birds to humans, rarely from human to human infection.

- In 1999, in China and Hong Kong, low pathogenic avian influenza A H9N2 was found in 2 children and caused uncomplicated influenza. Both patients were cured and there were no more cases.

A tip virus

The source of the disease is unknown, but there is evidence that poultry is the source of transmission and the main mode of transmission is from birds to humans. However, the possibility of human-to-human transmission cannot be excluded. Many other cases of H9N2 infection in humans have been reported by China in 1998-1999.

- In 2002, in the state of Virginia (USA), evidence of H7N2 infection was detected by a serological test in a person after an outbreak of H7N2 in poultry.

- In 2003, it was still in China and Hong Kong, there were 2 cases of highly pathogenic influenza A H5N1 virus occurred in two Hong Kong family members who have traveled in China. One person passed away, one died. How and where these two people are infected is unknown. Another family member died of respiratory disease in China but was not tested.

- In 2003, in the Netherlands, influenza A H7N7 outbreak in poultry of many farms. 89 people identified as infected with influenza H7N7 in combination with outbreaks in poultry. Most occur in poultry farmers. 78 cases of H7N7 infection but only pink-eye, 5 cases of pinkeye and flu-like symptoms with cough, fever and muscle pain; 2 cases just like flu .

Of the 89 cases of 1 death, occurred in a veterinarian after visiting a farm with avian influenza, showing signs of acute respiratory distress syndrome. The majority of patients are due to direct contact with infected poultry but the Dutch side said there could be 3 cases of infection from poultry farmers to family members. Since then there have been no further reports of H7N7 infection among people.

- In 2003 , a child infected with a low-pathogenic influenza A H9N2 virus was confirmed in Hong Kong; He was hospitalized and recovered.

- In 2003, found a patient in New York who had respiratory symptoms and tested for early infection with influenza A virus suspected to be H1N1, but later confirmed that the patient had been infected with influenza A H7N2 virus. from poultry.

- In 2004 , many poultry farmers in Canada were infected with highly pathogenic influenza A virus H7N3 in combination with an outbreak in poultry, but the disease caused by H7N3 was only mildly manifested by eye infection.

- In 2004 and 2005 there were many outbreaks of H5N1 avian influenza virus that could cause high disease in Thailand, Vietnam and many other places in Asia and have been confirmed by the World Health Organization.

What are the symptoms of bird flu in humans? May be flu-like symptoms (fever, cough, sore throat, muscle aches) to pinkeye (conjunctivitis), pneumonia, acute respiratory failure, viral pneumonia and many serious complications Other life threatening.

How effective is the current anti-influenza drug? Four types of antiviral drugs, amantadine, rimantadine, oseltamivir and zanamivir, are approved by the US Food and Drug Administration (FDA) for the treatment of influenza, three drugs are approved for prevention. All four drugs are effective against influenza A virus.

However, sometimes influenza viruses can become resistant, so drugs are not always effective. For example, analyzing some H5N1 viruses isolated from poultry and humans in Asia has shown that the virus is resistant to two drugs, amantadine and rimantadine. Monitoring of influenza A virus resistant poultry is still ongoing.