The Diagnosis Of Sspe Biology Essay

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The infection and spread of the measles is a major problem for the Global Health Response and disease control; as their aims was to reduce mortilaity rates between 1990 and 2015. [5] The measles is an acute, extremely infectious disease because it is a single stranded RNA which is gram negative virus. The measles enter the body via the nose and throat by air-bourne transmissions. [6] This is generally caused by coughing or sneezing of an infected person in close proximity. Once in the atmosphere, the measles virus can survive in water droplets for approximately 2 hours. As measles only affects humans; humans are the only reservoir as the host. Therefore, direct transmission occurs as the measles initially affects the upper respiratory system. As the measles can survive outside the body for 2 hours, it can be eliminated by UV/high temperatures. [7] This further explains why the measles are a world wide problem and why elimination of the disease is difficult. The measles virus has a helical RNA with proteins enclosed in a nuceocapsid. These proteins are a fusion protein and haemaglutinin enclosed within a lipid bilayer. This image shows the measles virus as a cell and its receptor sites. This image is from http://www.microbiologybytes.com/blog/2008/08/page/2.

The virus can then attach its receptors to a host cell and RNA replication can occur. [8] This occurs in the upper respiratory system, where the measles virus takes control of a host cell. It injects its RNA into the cell where the RNA undergoes transcription into code proteins. Furthermore, the virus replicates its RNA and the new virus assemblies. Eventually this causes cell lysis and many more measles viruses are released upon the body. [9] Once the virus spreads, it moves to the lymph nodes where it infects the body's immune response. This is a severe problem for those with cellular immunodeficiency's, as the measles primarily affects the lymph nodes. Within the immune system, the virus affects the CD+4, which binds to MHC class II molecule, and CD+8, which binds to MHC class I molecule. During the measles, levels of CD+8 have increased during the period where the patient has the rash and a T-lymphocyte pool develops with specificity for the measles virus to try to counteract it. [10] With CD+4, there has been an increase in amounts, to try and stimulate an immune response. Further analysis has proven that the measles virus causes an increase in Th2 cytokines such as IL-4 and IL-5. In a normal immune response,IL-4 induces B-cells and promotes a class switch to IgE and IL-5 promotes B-cell differentiation. [11] The affect of the T-lymphocytes has been evaluated by analysis and has been suggested that direct viral killing of an infected cell leads to an immunosuppressant [12] . This is defined as the primary viraemia. The secondary viraemia then occurs when the virus has entered the body, has spread to other parts of the body and its organs. In the measles; it spreads to the skin and renal system. Research has proven that the measles virus returns to the initial step of replication to replicate once more and with efficiency. This can cause serious problems for the bodies organs as the measles virus replicates in the epithelial walls of the major organs, which can be fatal [13] . However, a serious problem is when a patient with HIV contracts the measles. As HIV is an immunodeficiency disease, the measles is therefore more severe and much more chronic. A study in Sub-Sahara Africa by the Havard Medical School, Boston, Massachusetts shown that children with HIV had a more fatal form of measles and those who were not HIV affected did not, therefore, the measles wasn't as fatal. These recent tests showed that the measles were much more complicated with those with HIV. [14] 

Initially the symptoms of the measles begin like a common cold with signs of nasal discharge, dry cough, fever and watery red eyes. During this initial stage white spots can occur on the cheeks, with further development in the mouth and throat. A major symptom is fatigue and general irritiability. Aches and pains follow, which are commonly associated with influzena symptoms. However, these are cautious signs of the measles development. A characterised symptom of the measles are red spots with a white/blue centre which appear on the face. These are scientifically known as Koplik's spots [15] . The customarily known measles rash, has a brick red blotchy appearance, initially on the forehead before spreading to the limbs onto the rest of the body. This vital symptom must be recognised as it is a key symptom of the measles. Additional symptoms include vomiting and diarrhoea and secondary infections such as ear infections or pneumonia. Furthermore, the diarrhoea can cause dehydration and can become fatal if the patient is left to dehydrate. Therefore, the patient must continue to intake fluids [16] . A secondary infection of the measles is conjunctivitis as the eyes are red and watery and can cause further blindness if left untreated.

The development of a vaccination was first discovered by Edward Jenner in 1796 when he found that the dairy maids to worked with cowpox, where immune to smallpox [17] . Further developments of vaccination have been a major significant discovery in order to control the measles virus. It became available in 1963 by Dr. Maurice R. Hilleman and with over 500 million measles vaccines distributed

worldwide since 1970. [18] This graph shows the cases of measles in the US from 1950-2001. Once the vaccine was released, the number of cases fell dramatically. This graph is from www.cdc.gov/vaccines/vac-gen/images/measle. The development of the measles virus included testing the growth of the virus on chick embryo tissue culture. [19] Furthermore, this experiment is used globally and the vaccine is a weakened form of the measles virus. The first vaccine is given to a child at 12-15 months and the second dose is given at 4-6 years old, just before the child begins primary school. Research by the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib University, Bangladesh; showed that newborn babies had a higher measles IgG antibody titre and babies at 6-7 months had a significantly less amount of antibodies. This suggests that certain antibodies may cross the placenta during pregnancy. Therefore a vaccine at 12 months is perfect as it'll boost the immune system. The study furthered showed that a newborn antibody level was at 348.8mlU/ml decreasing steeply to 19.2mlU/ml at 6-7 months. When the vaccine is administrated into the child, the immune system recognises the foreign measles virus and the B-lymphocytes produce antibodies enable to fight the measles, furthermore, making memory cells, so if the body comes into contact with the virus again, the memory cells will differentiate and destroy the virus. [20] However, with every discovery, there are side-effects, on the contrary, severe allergic reactions are rare and the most common side effect maybe a rash or fever. A major enquiry of the measles vaccine is whether it can be a cause of 'autism'. Though the studies by the National Academy of Sciences Institute of Medicine review that there is no scientific evidence linking any vaccines, including measles to autism. [21] A further discovery asks adults to review their dates of vaccination as measles immunity in adults is undergoing a new review. Re-immunization maybe required such as a booster. In developing countries, there is a chance that an infant may encounter the virus before the age of one, therefore, the first vaccination does may be administrated by 6 months old. Furthermore, the measles should not be administrated to a HIV positive patient as it is a immunosuppressant disease and the vaccine is a live virus; it will have devastating effects on the individual. [22] 

Subacute sclerosing panencephalitis (SSPE) is a degeneration of the brain and is fatal. It is further known as an infection of the nervous system. It is quite a rare disease but without treatment of the measles, it can occur. During viraemia, it gains entry to the central nervous system, where it undergoes viral replication with the help of an immunopathological mechanism. It is slow progressing disease as it can occur up to 7 years after the initial measles virus. It is occurs more in children and young adults. The initial symptoms begin with interlectual deterioration and secondary symptoms may occur several months after, including convulsions, aphasia (which makes it harder for the patient to read and write as this particular part of the brain is affected: frontal and temporal lobes) and jerks. Furthermore, blindness may occur. If a lumbar puncture is taken, viral antigens may be found in the CSF. In addition to this, viral nucleocapsids, which are also found in the measles virus, is found in the cytoplasm. These nucleocapsids can travel from cell to cell. Scientists have encountered many experiments to enable to learn more about the disease. Yet a major discovery was that SSPE, extracted from patients had the measles mRNA and showed a high rate of mutation. Many of these mutations were in the M-gene and the some of the measles virus was recovered from the brain. Unfortuantely the virus can not be controlled. [23] In SSPE patients, there are 4 main stages attributed:

cerebal changes. Generally 1-2 months

Convulsions and worsening conditions

Coma and worsening neurological statis

Autonomic Dysfunction.

A CT scan can be used in the diagnosis of SSPE revealing atrophy in the brain and white matter involvement. The protein levels in the CSF also reveal dramatically increasing levels of IgG trying to counteract the measles. Within 5 years of diagnosis, it has been recorded that 95% patients suffering SSPE die, as there is no treatment. However, it can remain manageable with anticonvulsant therapy.

Overall, the measles remain a possible killer disease especially if it remains untreated. The measles remains highly contagious and it has supplementary secondary problems such as SSPE and blindness. It continues to be a problem for the Global Health Response and with further research hopefully it can be eradicated worldwide.

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