Epidemiology and Prevention of Vaccine-Preventable Diseases, Research Paper Example

Mumps, a contagious disease known as epidemic parotitis, is a viral disease that affects humans.  The basic symptoms of mumps starts with the first few days of a fever, headache, loss of appetite, lethargy, muscle aches, and then is followed by the swelling of the salivary glands.  A vaccination program has been introduced into the United States, as the mumps was a common illness in infants and children; therefore, individuals who are not vaccinated are not immune from obtaining the mumps infection.  Due to the introduction of the vaccination to the United States, mumps has become a rare viral infection within the United States.  (CDC, 2014) The current paper discusses thehistory, epidemiology,symptoms, virulence, treatment of the disease and vaccination.

The disease was first noted or explained during the 5^th century by Hippocrates. The disease was described a mild epidemic that was associated with the swelling near the ears and painful swelling of either one or both testes. The common name, mumps, was derived from the old English word meaning to grin or mumble. During the 18^th century, a physician named Hamilton was the first to describe the disease as associated with the central nervous system (CNS) after an autopsy from a fatal death of a patient.  As time progressed, other studies showed that the virus was a leading cause to the viral meningitis and encephalitis. It was not until the year of 1935 that researchers were able to transmit the disease between monkeys and children in order to isolate the virus. The isolation of the virus leads to the development of the first vaccine in the year 1958. The disease has historically been known as not a sever disease during childhood; however, the mumps was a concern to the military, as it was prevalent during the Civil War, as well as World War I and II.  (Rubin et al.)

The mumps virus is a paramyxovirus, which is a single-stranded RNA virus that occurs worldwide.  The carrier state for the mumps disease is unknown; however, mumps is a human disease that has been known to be transmitted from asymptomatic people and is contagious. In fact, the contagiousness of mumps is similar to the flu or influenza, rubella and respiratory syncytial virus (RSV). (CDC, 2012, Rubin et al.) The mumps virus is composed of protein particles that range in size from 100 to 600 nm, with a helical ribonucleoprotein core enclosed by a lipid envelope. The protein is a hollow tube in which the viral host cell envelope contains the viral proteins that project out of the surface of the cell.  Genetically speaking, the virus is composed of 15,384 nucleotides. An interesting aspect of the mumps virus, compared to other paramyxoviruses, is that the mumps virus does not have identical start and end genes.  (Rubin et al.)

The virus is from the family of virus known as, paramixoviruses, which also contain the commonly known viruses such as influenza and measles. Paramixoviruses consist of large virion proteins that have a negative RNA genome that is shaped in a helical nucelocapsid structure that is surrounded by an envelope that contains the viral protein, referred to as hemagglutinin-neuraminidase. (Rubin et al.) The spread of the disease occurs through droplets of mucus or saliva from the mouth, throat or nose of an infected person. This usually occurs through coughing, sneezing or talking. In addition, the virus can be spread if an individual touches a surface or an item that has been touched by a person infected that has not washed their hands and has touched their mouth or nose.  Once an individual has become infected with the virus there is an incubation period that averages between 16-18 days, however, it has been known to last anywhere from 12-25 days. (Immunization Action Coalition)

The pathogenesis of the mumps occurs in the nasopharynx and lymph nodes.  After the incubation period of 12-15 days, a viremia (virus enters the bloodstream) occurs and lasts between three to five days.  It is during the viremia where the virus spreads to many different tissues, such as the salivary glands, pancreas, ovaries, and testes. The infected tissues then undergo the symptoms of swelling.  (CDC, 2012)The infection of the meninges in the central nervous system is another symptom, known as meningoencephalitis, and occurs in up to 50% of the people who become infected. Cell-mediated immunity through vaccinations is essential for this virus, as antibodies within the immune system are not sufficient as the virus spreads from cell to cell.

The virus infects a host cells through the use of sialic acid.  Sialic acid is an acylderivative that is found on the cell surface of the glycoprotein and lips. The acid serves as a receptor for the mumps virus. After the virus attaches to a host cell on the receptor acid, the virus and the cell fuse together. After the fusion of the cell, the virus enters the cell and undergoes the genetic transcription and replication. In addition, since the mumps receptor is found on most cell types in mammal cells, the virus is able to infect most cells in the human body. Cellular aspects of the virus are found in large masses of the cytoplasm of the host cell. Experiments have shown that humans are in fact the only natural occurring host to the mumps virus, although researchers have been able to introduce the virus into laboratory animals, such as mice, monkeys, rats, and hamsters. The purpose of the introduction into other mammals was to study the pathogenesis of the disease. Introduction into other mammals has found that the mumps virus results in an inflammatory response to include meningitis and encephalitis, as well as hydrocephalus (swelling of the brain). These findings are cohesive with the features that are present in humans. (Rubin et al.)

The symptoms of mumps include the feeling of being sick, such as fever, headache, and loss of appetite.  The most common manifestation in the mumps is known as “Parotitis”.  Parotitis occurs in about 30-40% of the patients and is a combination of a single or multiple swelling of the salivary glands.  Parotitis is known to begin to occur within the first two days of the infection.  Patients have identified the sensation of parotitis as an earache or tenderness on the palpation of the jaw.  The symptoms of the mumps usually go away after one week to 10 days.  In addition, 20% of the mumps cases are asymptomatic with an additional 40-50% of the people having only primary respiratory symptoms.  (CDC, 2012)   Transmission of the disease has been indicated through the spread of droplets.  Research has found that the virus can be shed in the saliva or droplets as little as six days before onset of the symptoms. The ending of the viral release of droplets has been determined to stop after immunoglobulins A and M present them thought the immune system. Therefore, people with mumps are able to spread this disease through the respiratory tracts for greater than 10 days.  The virus disappears when the Mumps antibody becomes detected around 11 days after the initial infection. (Rubin et al.)

The initial symptoms of the viral infection involve the parotid gland. In the parotid gland, the virus affects the epithelium tissue, which results in the inflammatory response, such as swelling and inflammation, as well as tissue damage. The mumps virus then invades the CNS, in some patients, approximately 10%. The virus can also lead to encephalitis, which has been reported in around 0.5% of cases.  Before the introduction of the mumps vaccination, the mumps virus was the leading causative factor for viral meningitis. In addition, the neurological symptoms of the mumps virus appear to be more prevalent in males compared to females at a 3:1 ratio.  (Rubin et al.)

The complications of the mumps correlate with the central nervous system reactions, as mentioned above, such as meningitis or encephalitis.  Although the CNS symptoms occur in less than 10% of individuals, the involvement of the virus occurs asymptomatically in 50-60% of the patients.  In addition, adults affected with mumps virus are at a higher risk for complications with the CNS compared to children. Another complication in post-puberty males is the inflammation of the testes or orchitis. This symptom has been noted in up to 50% of the patients and usually occurs after parotitis has persisted. In addition, the swelling of the testes can be bilateral or unilateral. Bilateral occurrences are approximately 30% in males affected with mumps virus.  The swelling of the ovaries in females also occurs in post-puberty females. The occurrences are rare at around 5%. Pancreatitis occurs in patients that do not exhibit parotitis with the mumps virus.(Rubin et al.)

One of the major complications to the mumps virus is deafness. Deafness has occurred in approximately 1 in 20,000 reported cases of the mumps. The hearing loss is unilateral, occurring in only one of the ears, in most of the cases, but the onset is sudden and results in the permanent loss of hearing. In addition, myocarditis of the heart organ has been observed in approximately 3-15% of the patients with known viral mumps; however, recovercan be complete. Other complications occur in mumps patients, such as arthritis and nephritis.  Since the introduction of the vaccination, deaths from the mumps have decreased to one death per year as reported during the years 1980-1999.  (CDC, 2012)

The diagnosis of the mumps virus in a patient is usually observed through the clinical symptoms and the presence of parotitis.  However, the mumps virus can be isolated through clinical laboratory testing.  A swab is used to isolate the virus from the parotid duct, or other affected salivary glands.  If mumps is suspected, the collection of a specimen is recommended. The laboratory exam used to detect the mumps virus is the polymerase chain reaction (PCR) technique.  In addition, an enzyme immunoassay (EIA), can also confirm the mumps virus through blood serum.  The EIA is the most commonly used test for the mumps virus.  The EIA test detects the immunoglobulins IgM and IgG as they become detectable during the beginning days of the disease and reach a  peak number after about a week after the onset of symptoms.  (CDC, 2012)

Once a patient is diagnosed with the mumps virus, there is no cure, only supportive treatment, such as fluids, bed rest and reduction. Therefore, if someone has been exposed to the mumps virus and has not been vaccinated, the symptoms should be carefully watched. If the individual did not become affected from the exposure, the vaccine can help with future exposure. Since the vaccinations are required in the United States for children, the number of cases has decreased from an estimated 212,000 reports during the year 1964 to 229 reports in 2012. Large outbreaks did occur in the United States, however during the years 2006 and 2009-2010.  (CDC, 2012)

In regard to the vaccination, one dose of the vaccine is recommended for children starting at the age of 12 months, as well as for older individuals who were born after 1957.  It is important to note that children who were vaccinated with mumps containing vaccine prior to 12 months of age, should be re-vaccinated.  In addition, it is recommended that a second dose of the vaccine that are at high risk for the disease or mumps exposure be given. Furthermore, the combined vaccination, known as the MMR (Measles, Mumps, Rubella) is recommended at both doses. The second dose is recommended to occur between age 4 and 6, or before the child enters either kindergarten or first grade.  (CDC, 2012)

The mumps vaccination produces a mild infection, compared to the full onset of the disease.  It has also been found that the recipients of the mumps vaccination develop the antibody at measurable quantities.  The duration of the vaccine immunity is thought to be lifelong.  It is therefore important for vaccinations to occur in children in order to keep the occurrence of mumps in the United States at low densities.

References

CDC.  (2014). Mumps. Retrieved from: http://www.cdc.gov/mumps/

CDC.  (2012).Epidemiology and Prevention of Vaccine-Preventable Diseases. Retrieved from: http://www.cdc.gov/vaccines/pubs/pinkbook/mumps.html

Immunization Action Coalition.  Mumps: Questions and Answers. Information about the disease and vaccines.  Retrieved from: http://www.immunize.org/catg.d/p4211.pdf

Rubin, SA., Sauder, CJ., Carbone, KM.    Chapter 35: Mumps Virus.  Pp 1024-1041.Retrieved from: http://bookpromos.lww.com/wp-content/uploads/2013/07/CH035.pdf