Bird Flu Virus (H5N1), Health Implications, Global Distribution & Recommendations for Prevention

Bird flu virus is fast becoming one of the main emerging viruses of the twenty-first century, threatening human health and wellbeing. This virus was first discovered in Italy 100 years ago and is now found worldwide. The virus shot into spotlight when human cases of the disease were reported in South East Asia and continues to pose a threat to the human population and if the proper corrective actions are not adopted in a timely manner this virus may lead to the next pandemic of this century. There are fifteen types of bird flu viruses of which H5 and H7 are the most contagious and fatal in birds. The type currently causing concern is the deadly H5N1 strain. Variations in the H5N1 type have been reported in different countries affected with bird flu outbreaks. Natural carriers of the bird flu virus are migratory wildfowl of which wild ducks form the largest group. These carriers like human carriers of viral infections do no show any signs of the disease and are unlikely to develop an infection. However, domestic birds are particularly susceptible to the H5N1 virus. Wildfowl and other migratory birds store the H5N1 stain of virus in their intestines and the virus is passed out in the feces. Dried feces can become pulverized and transported in the wind where it can contaminate and infect other birds and humans. Humans can become infected by inhaling particles of feces containing H5N1 virus. Common symptoms of H5N1 resemble other flu symptoms such as fever, soar throat, coughs, malaise and conjunctivitis. Researchers have now found that H5N1 virus can infect other body parts including the lungs. In 1977 the first human cases of bird flu were seen in Hong Kong. According to the World Health Organization 118 confirmed cases of bird flu have found in humans in Indonesia, Vietnam, Thailand and Cambodia leading to 61 deaths as of 20th October, 2005. The bird flu virus (H5N1) is capable of and is believed to be transferred from human to human. Some isolated cases from been documented and are as follows: (i) a case in Thailand where a girl acquired the disease from her mother who also died, (ii) in 2004, two sisters died in Vietnam after contracting bird flu from their brother who had died form an unidentified respiratory illness, (iii) in 1997, a doctor caught the disease from a patient with the H5N1 virus. Could rapid transfer of the H5N1 virus between humans mean a possible pandemic? This is a frightening possibility and is most feared outcome since it is now believed that the pandemic that occurred in 1918 was caused by an avian flu virus. Researchers are now examining the possibility that the H5N1 virus could exchange genes with the common human flu virus. If this occurs in the case of simultaneous infections this may lead to a possible pandemic. But, based on the pathogenic pattern of the H5N1 strain, this strain so far only infects or is transferred to close relatives and stops there. This may be a sign of relief, but if the H5N1 virus acquires the ability to transfer between humans, scientists estimate it may be catastrophic leading to at least 2-50 million deaths worldwide. At present there exists no definite vaccine against the H5N1 virus. Several prototypes are being developed that may offer protection. Antiviral drugs such as Tamiflu are available that may reduce symptoms and limit the spread of the virus. Recently, a Vietnamese patient who was infected with H5N1 has become resistant to Tamiflu. Experts are now suggesting that it may be helpful to use other drugs from the same family such as Relenza (zanamivir). What measures can be taken to prevent the spread of bird flu virus (H5N1)? Several measures may be implemented to prevent the spread of H5N1: (i) Culling of infected birds to prevent the transmission of the virus to humans. (ii) Quarantine and treat infected human promptly with antiviral drugs such as Tamiflu or other similar drugs. (iii) Pens should be protected from wildfowl and migratory birds. (iv) People who are engaged in cleaning, slaughtering and processing of poultry should take the necessary precautionary measures to prevent themselves from being infected and minimize the spread of infection. (v) Monitoring of the migratory patterns of wild birds should provide early alerts of the arrival of infected birds which could then be targeted on arrival. (vi) People who eat poultry are not at risk for the H5N1 strain, but precautionary measures such as cooking all meat to a temperature of at least 70