Dealing with Avian Influenza and Other Viral Infections
Background
Influenza or “the flu” is a contagious illness that is caused by a variety of viruses collectively known as the influenza virus. The influenza virus can survive in a number of animal models and generally, specific animal classes are infected by specific types of influenza viruses. For instance, humans are typically vulnerable to infection from three strains of the influenza virus, H1N1, H1N2, and H3N2. Once an individual is infected with a strain of influenza, their immune system will develop antibodies to that strain which reduces the likelihood of their becoming ill from that particular form of the virus from subsequent exposures. However, like most viruses, influenza viruses have the ability to mutate. Over periods of time these mutations can cause enough change in the virus so that a person’s immune system may not recognize this new form, allowing the person to become ill from a second exposure to the same virus. This ability to mutate leaves vaccine manufacturers guessing as to which strain of virus and which mutation of each strain is going to be most active each flu season, as vaccines are specific to both strain and mutation. Thus, the efficacy of each year’s vaccine depends on the ability of the vaccine manufacturers to anticipate the particular form of the virus that will be most active that year.
Recently, avian influenza has been receiving a great deal of attention because, unlike most influenza viruses, it has developed the ability to infect several different types of animals. As the name denotes, avian influenza A H5N1 is a strain of the virus that, up until recently, has been seen predominantly in birds. Recently, infections of the H5N1 virus have been observed in a number of mammalian species including humans. This ability to “jump” has epidemiologists particularly concerned because humans have very little, if any, immunity to this strain of the influenza virus. The method(s) by which the virus is spread to humans is still unknown; however, at this time, it appears that A H5N1 is primarily spread to humans from birds by way of their body fluids. Few cases of the virus spreading from human to human have been observed and these infections do not seem to spread beyond one person. However, concerns about a possible human pandemic of avian flu exist because the virus has shown the ability to infect humans and further mutations may allow it to be spread easily form one person to another. The mortality rate in observed cases of human infection is approximately 50%, which may be due, in part, to the lack of human immune response to the virus. Care should be used when interpreting this data however, as it is unknown if this represents a true mortality rate, or if it is the mortality rate of only those who are the sickest and are thus most likely to gain the attention of health care workers.
Preventing Avian Flu and Other Viral Infections
Currently, there is no vaccine for bird flu and information must be gathered about the virus before an effective vaccine can be created. Should outbreaks of human to human infection occur, perhaps the best preventative measures to minimize the spread of the virus will be the practice good hygiene and quarantining infected individuals. The virus survives most prevalently in feces and in the fluids of the upper and lower respiratory tracts. Exposure to these elements from an infected individual will place a person at higher risk for infection. Coughing, which is a common symptom of flu sufferers, expels the virus into the air where it can gain direct access to the respiratory tracts of nearby individuals. A second method of transfer can occur when an infected individual touches the areas around their nostrils, mouth, or eyes and transfers small amounts of virus laden body fluid to their hand. The person may subsequently touch a doorknob, pen, water fountain, etc. and transfer the virus to that object. Once on this object, the virus can survive for several hours. If during this time, a second individual touches the object with their hands and subsequently touches their nose, mouth, or eyes, they can be infected with the virus.
Thus, the spread of the virus can be effectively curtailed by encouraging infected individuals to stay home and reduce the number of opportunities the virus has to find new hosts. Heeding this advice is particularly effective early in the illness as the virus is typically more contagious in the early period after infection.
Because exposure to infected individuals cannot be eliminated, hand washing is particularly important in reducing the spread of viruses. Hands should be washed frequently throughout the day, especially after exposure to individuals who are infected, or who are suspected of being infected. Contact with infected individuals can be either direct, such as a handshake, or indirect, such as a visit to their office or the passing of a hard copy memo. Hand washing should be thorough, with each finger being scrubbed individually and special attention given to the areas around and under the fingernails. Soap should be used, but the use of special “antibacterial” soaps is of no added benefit, as these soaps are designed to kill bacteria and provide no extra protection against viruses. Afterwards, dry your hands thoroughly with paper towels. Drying your hands in this manner can fight the virus in two ways: it deprives the virus of the moist environment it needs to survive and the abrasive action of the paper towel over the skin can actually kill the virus. Finally, don’t think that there is no point in hand washing if you are already sick, as hand washing can reduce the severity of an outbreak by keeping you from spreading the virus to others.
Symptoms and Treatments
Symptoms of avian flu are similar to those of other influenza infections such as fever, sore throat, cough, muscle aches and eye inflections. Influenza also leaves patients susceptible to secondary infections such as bronchitis and pneumonia. There are few medications that can actually fight viruses themselves and the ability of antiviral medications to combat the avian influenza virus is unknown. Perhaps the best available treatments for individuals suffering from influenza are rest and the use of antihistamines, decongestants, and expectorants to lessen the chance of secondary infections. However, check with your physician as new treatments to combat the virus may become available.
Should bird flu become established in the human population in pandemic or epidemic proportions, the duration and severity of this event cannot be predicted at the present time. Prudent action in response would be dictated by the nature of the outbreak and would likely be provided by the Centers for Disease Control (CDC). However, we can all do our parts to minimize the likelihood of a severe outbreak of influenza or other viral infections by adhering to the aforementioned advice on hygiene and proper treatment of infected individuals.
References
Centers for Disease Control Website – http://www.cdc.gov.