Emerging Infectious Diseases
Emerging Infectious Diseases
Emerging infectious diseases are diseases that are new or changing, and are increasing, or have the potential to increase in incidence in the near future. (Pearson, Microbiology) Some important contributing factors to the development of EIDs are evolutionary changes in existing organisms, the movement of previously identified diseases to new geographic locations and populations by modern transportation, and increased human exposure to previously undocumented, uncommon infectious agents in areas of ecological growth or change.
This includes previously uninhabited areas that may be undergoing deforestation or construction. EIDs also emerge as a result of resistance, and in recent years, an unusually high incidence of EIDs has drawn the attention of the global population in reaction to unsatisfactory health care facilities and geographic locations with tendency toward breakdown of public sanitation measures. (Pearson, Microbiology) Avian Influenza A (H1N1), or bird flu, became a subject of global attention in 2003 when it caused he death of millions of poultry and 24 humans in eight countries in central and south Asia.
Avian Influenza A is transmitted by birds around the world, however, certain wild birds, particularly waterfowl, do not get sick but instead carry the virus in their intestines and release it through their excretions. Most frequently, wild birds spread influenza to domesticated birds and poultry farms, where the virus causes death. Most avian influenza viruses actually do not naturally cause disease in humans. However, some Influenza strains, like Avian Influenza A, are zoonotic, meaning that they can infect humans and cause disease possibly resulting in death. World Health Organization) The NS1 protein of the influenza virus is the most critical virulence factor that allows it to antagonize the host’s antiviral response. In doing this it employs several mechanisms, including the binding and sequestration of double-stranded RNA. The structure of full-length NS1 protein has now been identified using samples from a virulent H5N1 avian influenza virus strain. “The molecule’s RNA binding domain displays noticeable differences when it is compared to that of the non-H5N1 strains, whereas the effector domain is significantly altered.
The two domains interact in such a way as to form tubules that may act to sequester dsRNA, allowing the virus to evade the host’s innate immune response. ” (International Weekly Journal of Science) The following groups od individuals are at an increased risk for contraction Avian Influenza A: Farmers and others factory farm workers who handle poultry, Travelers who may be visiting visiting affected countries during an outbreak, Those who touch an infected bird, or Those who consume raw or undercooked poultry products from birds infected with the disease.
Health care workers may also be at an increased risk of contracting the bird flu from an infected patient. (NYT Heath Guide) The avian flu virus (H5N1) has been proven to survive in the environment without the help of a human or animal host for long periods of time. Infection is possible simply by touching contaminated surfaces. Birds who were infected with Avian Influenza A can continue to foster the virus and release it in their excretions for as long as 10 days, and are still a risk after death. NYT Health Guide) Infection with the H5N1 virus in humans causes flu-like symptoms that often progress quickly to more adverse complications such as Acute Respiratory Distress, Organ failure, pneumonia, sepsis or death.
The initial onset of symptoms may include cough, diarrhea, difficulty breathing, unusually high fever, headache; muscle aches, a runny nose or a sore throat. NYT Health Guide) Tests to verify Avian Influenza in an individual exist, but are currently not widely available to the public. If you are unable to receive a preliminary test which yields results in four hours, your physician may also conduct the following tests: Auscultation, to detect abnormal breathing and lung function, a chest x-ray, a nasopharyngeal culture and blood work, all to determine the presence of the virus in an individual based on their bodily immune functions. (World Health Organization)
Many strains of the influenza virus have become resistant to the effects of the antiviral drugs that were previously being used to treat them. Health officials are now recommending the use of Oseltamivir, known as Tamiflu and possibly Zanamivir, known as Relenza as the newest, most helpful pharmaceutical treatment options. (Mayo Clinic) These drugs must be taken within forty-eight hours after the appearance of symptoms in order to be effective, but this may prove as a roblem in the vent of a global outbreak. Because of the short supply, it’s not entirely clear how Influenza drugs would be distributed and administered if there were an epidemic of global proportions. In terms of prevention, physicians recommend that all healthy patients receive an influenza shot (commonly called a “flu shot”) to reduce the likelihood of an existing avian flu virus mixing with a human flu virus, which would create a new virus that may easily spread and cause an epidemic.
The U. S. Food and Drug Administration has approved a vaccine to protect humans from the avian flu, and experts say that the vaccine could be used if the current H5N1 virus began spreading between humans. (NYT Health Guide) Human infections with Avian Influenza viruses detected since 1997 have not yet resulted in sustained human- to-human transmission. However, because Influenza Viruses have the potential to mutate and gain the ability to spread easily between people, monitoring for inter-human transmission is extremely important.
University/College: University of California
Type of paper: Thesis/Dissertation Chapter
Date: 13 October 2016
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