Epidemiology of Influenza

As we welcome the winter season every year, we also welcome the possibility of various communicable diseases that are prone to present during the winter season. Diseases such as pneumonia, measles, chickenpox, and influenza are some of the diseases that make their annual debut during the winter season. These diseases affect certain parts of the body in which compromise ones health in one way or the other. Influenza is a communicable infectious viral disease which has the potential to occur as a pandemic, epidemic, or outbreak. Each year the influenza vaccine is offered in order to prevent and/or lessen the effect of the disease. In this paper the communicable disease influenza and its effect of the body and environment will be discussed. Communicable diseases are diseases that can be spread from person to person. In order for communicable diseases to make an impact, transmission of the infection must be evident from person to person. When large populations are infected with a disease, whether it is communicable or non-communicable, and epidemiology comes into play. Smith and Maurer describe epidemiology as the study of communicable diseases affecting large groups of people or populations (2009). Prevention play a major role in regards to preventing and decreasing the transmission of communicable diseases. Communicable diseases have chains called the epidemiologic triangle. In order to interrupt transmission, the triangle must be broken at the weakest link. The communicable disease chain includes the infectious agent which is the microorganism, the host which is the person or animal which incubates the agent and finally the environment which is conducive to growth and further nurturing of the microorganism (Smith and Maurer, 2009). This chain is the route the microorganism takes to be transmitted. Influenza is a contagious infectious viral disease caused by either Influenza type A or influenza type B which commonly spread among humans. Influenza type C causes mild respiratory illness. According to the CDC, the type of the virus depends on the surface protein present on the virus (CDC, 2014). Types A and B are responsible for the seasonal epidemic of the disease every winter. Influenza type A can be broken down into subtypes and strains based on two different proteins on the surface of the virus known as the hemagglutinin (H) and the neuraminidase (N). The difference in the surface protein determines the variation of the disease (CDC, 2014). In 2009 a new strand of the type A influenza surfaced called H1N1 which was different from the human influenza virus that was infecting humans at the time. This new strand of influenza caused the first influenza pandemic in over 40 years as reported by the CDC (2014). Transmission of the influenza virus from human to human can happen in three ways: infection can result from direct contact with others who are infected, contaminated objects and lastly by a person inhaling viral particles in the air, aerosols. The smaller the particles are the higher they are able to suspend in the air and in the same manner, the smaller the particles are, the lower they can go into the respiratory tract to cause infection. This is how pneumonia may result from the infection (CDC, 2014). According to Smith and Maurer, the amount of agent which is known as the infective dose needed to produce illness can vary. The more infective the agent is the less exposure required to produce illness (2009). The higher the virulence of the microorganism, the more potent. The determinants of the disease are based on the exposure to the microorganism. Anyone can contract the flu by coming in contact with an infected person or object. Practice in hand washing is a major part of prevention of the spread of such microorganisms. Factors that contribute to the spread of influenza is not practicing hand washing, infected individuals not covering their mouth while coughing or sneezing, and contaminated objects easily accessible to others in the environment. Influenza is a respiratory illness that comes on suddenly. Influenza virus is different from the common cold. Signs and symptoms of influenza may include but is not limited to fever, chills, coughing, sore throat, muscle and body aches, fatigue and vomiting and diarrhea (CDC, 2014). Vomiting and diarrhea more often presents in children and not in adults. Sometimes there are complications induced by the influenza virus. As previously mentioned, influenza is a respiratory illness which means that there is impact on the lungs. When many people are infected with the flu virus medical attention and medication is not requires because the illness passes within a few days to two weeks.
Sometimes there are complications of contracting the virus. Some of the complications include but are not limited to pneumonia, bronchitis, sinus and ear infections. Complications of influenza can lead to hospitalization and even death in some cases. People who are more prone to complications of the influenza virus includes children younger than five but younger than two years of age, elderly adults that are 65 and older, and pregnant women (CDC, 2014). People who have asthma, heart disease, weakened immune systems, chronic lung disease such as chronic obstructive pulmonary disease (COPD) and cystic fibrosis, diabetes and sickle cell disease are also individuals who are likely to have complications from contracting influenza (CDC, 2014). The morbidly obese and those on long term aspirin therapy are also among those at risk for complications.
Prevention is the best treatment of any disease however vaccinations and antiviral drugs

are available to treat influenza. The vaccination is updated and made available annually to prevent and/or lessen the effect of the influenza virus. In most cases medication and hospitalization is not required for those who have influenza as the virus usually run its course within two weeks. However, antiviral drugs are available and are used to help prevent serious flu related complications such as pneumonia. Antiviral drugs also shorten the time of sickness by one or two days (CDC, 2014). One of the drugs that are used to treat influenza is the antiviral drugs Tamiflu and Relenza. Tamiflu and Relenza are to be used within the first two days of symptoms of influenza and can be used by patients ranging in age from as young as two weeks to 65years and older. These drugs are used for those who are very sick or those who are at high risk of complications of influenza. The medication is to be taken for at least five days and sometimes longer if the patient is hospitalized (CDC, 2014). Influenza is a potentially dangerous communicable disease in that if the chain is not broken it can progress to complications such as pneumonia which has in some cases resulted in death. The epidemiology of influenza is that it has the potential to occur as a pandemic, epidemic, outbreak, or in sporadic cases. Influenza is a global issue in fact the CDC has a surveillance program to monitor the reported infections internationally. Global Alert and Response (GAR) reported to WHO that on as recently as November 15, 2014 there were three confirmed cases of the avian influenza A (H7N9) virus which resulted in one death in China (CDC, 2014). A cruise ship from New York to Montreal reported influenza which demonstrates how communicable diseases can be easily passed from person to person and be transferred across international borders. It was reported that 2.7% of passengers and 0.5% of the crew had acute febrile respiratory illness during or after the cruise and just that quickly influenza as in United States and Canada (WHO, 2014). The WHO’s Global Influenza Program (GIP) provides international global standards for influenza surveillance. They work to collect data from all around the world and provide countries, territories, and areas about influenza transmission (WHO, 2014). The role of the community health nurse is to educate the public about influenza transmission and prevention as well as educate and encourage the community to get the influenza vaccine. We are to collaborate with other health care workers to educate as many communities as possible. The CDC offers information about influenza and is a resource to learn about prevention as well. When it comes to influenza as well as other communicable diseases, prevention is the best treatment.

References
CDC: Influenza (2014). Seasonal Flu: Retrieved 11/28/2014 from http://www.cdc.gov/flu/about/disease/symptoms.htm
CDC: People at High Risk of Developing Flu-Related Complications. (2014). Retrieved 11/28/14 from http://cdc.gov/flu/about/disease/high_risk.htm Global Alert and Response (GAR) Human infection with avian influenza A (H7N9) virus- China. 18 November 2014. Retrieved November 27, 2014 from Http://www.who.int/csr/don/18-november-2014-avian-influenza/en
Goodband, A., Oakley, S., Rayner, J., Toms, J., & Brostoff, J. (2014). Influenza: disease, epidemiology and the importance of vaccination uptake by healthcare workers. Primary Health Care, 24(7), 33-38.
Influenza Surveillance and Monitoring (2014). Retrieved 11/27/14 from http://www.who.int/influenza/surveillance_monitoring/en/
Smith, Maurer and Community/Public Health Nursing Practice: Health for Families and Populations, 4th Edition. W.B. Saunders Company, 2009. VitalBook file.