Genera Morbillivirus Paramyxoviruse Measles Biology Essay

Published:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

Measles as research has shown is that it is an infectious disease that affects the respiratory system caused by the virus paramyxovirus which is the genera morbillivirus Paramyxoviruse are from the paramyxovirirdae family mononegavirales order. Being of the negative sense single stranded RNA viruses, they are responsible for several human diseases that affect human being especially measles that affect children new borns who have not been vaccine hence the numerous campaigns by Governments to vaccinate children. This disease as studies have shown mainly affects third world countries and hence the numerous funds to by the World Health Organization to these countries to mitigate the effects of these disease in those countries. [1}

Genus Morbillivirus- with the type species of measles, rindercine pest phocine distemper which should be noted that this disease s is highly infectious

Genus Avulaviru-s of the species Newcastle disease

Genus respivovurus- of the species sendai virus human parainfluenza and also this virus has been linked to common colds.

Genus rubulavirus-mumps, humanfluenza simian parainfluenza tuhokovirus, tioman virus

Genus Pneumovirinae-Tupaia paramyxovirus

Other viruses that have been linked to these family but comprehensive studies have not proven would include belong, Salem, nariva, Mossman and the fer-de-lance viruses

GENOME STRUCTURE

Gene sequence within the genome is conserved across the family due to a phenomenon known as transcriptional polarity in which genes closest to the 3' end of the genome are transcribed in greater abundance than those towards the 5' end. This mechanism acts as a form of transcriptional regulation.

The genome consists of a single NOT segment negative-sense RNA, 15-19 kilo bases in length and containing 6-10 genes. Extracistronic (non-coding) regions include:

A 3' leader sequence, 50 in length which acts as a promoter. which is transcriptional

A 5' trailer sequence, 50-161 nucleotides long

Intergenomic regions between genes which are three nucleotides long for morbillivirus, respirovirus and henipavirus, variable length (1-56 nucleotides) for rubulavirus and pneumovirinae. NB;Each gene contains transcription start/stop signals at the beginning and end which are transcribed as part of the gene.

The gene sequence is: Nucleocapsid - Phosphoprotein - Matrix - Fusion - Attachment - Large (polymerase)

PHYSICAL STRUCTURE

Virions are enclosed and can be circular and/ pleomorphic. The fusion proteins and the attachment proteins appear as spikes on the virion surface. Matrix proteins inside the envelope stabilise virus structure. The nucleocapsid core is composed of the genomic RNA, nucleocapsid proteins, phosphoproteins and polymerase proteins.

The protein structure would include the following

N - the nucleocapsid protein associates with genomic RNA (one molecule per hexamer) and protects the RNA from nuclease digestion

P - the phosphoprotein binds to the N and L proteins and forms part of the RNA polymerase complex

M - the matrix protein assembles between the envelope and the nucleocapsid core, it organizes and maintains virion structure

F - the fusion protein projects from the envelope surface as a trimer, and mediates cell entry by inducing fusion between the viral envelope and the cell membrane by class I fusion. One of the defining characteristics of members of the paramyxoviridae family is the requirement for a neutral pH for fusogenic activity.

H/HN/G - the cell attachment proteins span the viral envelope and project from the surface as spikes. They bind to proteins on the surface of target cells to facilitate cell entry. Proteins are designated by H i.e. hemaagglutin for morbilliviruses and henipaviruses as they posses activity associated with the above , observed as an ability to cause red blood cells to clump. HN ) attachment proteins occur in respiroviruses, rubulaviruses and avulaviruses. These possess both haemagglutination and activity which cleaves sialic acid on the cell surface, preventing viral particles from reattaching to previously infected cells. Attachment proteins with neither haemagglutination nor neuraminidase activity are designated G . These occur in members of pneumovirinae.

L - the large protein is the catalytic subunit of (RDRP)

Accessory proteins - a mechanism known as RNA editing allows multiple proteins to be produced from the P gene. These are not essential for replication but may aid in survival in vitro or may be involved in regulating the switch from mRNA synthesis to antigenome synthesis [2].

SIGNS AND SYMPTOMS

Normally it starts with four continous days of chronic fevers accompanied by blood shot eyes also known as conjunctivitis, runny noses often mistaken for common colds, the fever is characterized by temperature of upto 40 C .In addition rashes may be seen inside the mouth which in most assured cases of measles they are normally diagnostic i.e. Koplik's spots but it develops to what is known as the maculopapular, erythematous rash starting from the head and spreading to other parts of the body of which lasts up to ten days. It has an average incubation period ranging between 6-19 days and effects of the disease may be felt 2-4 days prior to the onset of the rash i.e. 4-9 days

Clinical Diagnosis

This may require a history of the above symptoms especially fever symptoms for three days and also the observance of the koplic spots

Through the use of laboratory prognosis done with confirming presence of IgM antibodies in addition to the isolation of measles virus RNA from obtained respiratory specimen I n children conduct IgA test from the saliva for measles Positive contact with any infected person through semen during sexual intercourse saliva and mucous may cause infection and may add reliable epidemiological evidence

METHODS OF TRANSMISSION

The most common method is through contact with fluids from an infected person's nose and mouth either directly through sexual intercourse ,mucous or aerosol transmission

PREVENTION

1.Immunization of children especially in developed countries is done compulsorily at the age of 18 months usually as part of a 3 tier immunization i.e. measles, mumps and rubella. It is usually advisable not to vaccinate before 18 months since children under this age retain their antibodies transmitted by mother to child at birth

2.Another second dose given when the between the ages of four to five and the vaccination rates should be high enough to make measles an uncommon as possible and also to increase the rate of immunity

However in developing countries it is a pandemic and therefore the world health organization has recommended that it is administered at least between 5-9months regardless of HIV infection or not and also should be supplememented by other immunizations of other diseases that cause high rates of child mortality rates

TREATMENT

First of all it is imperative that in case of reported signs of measles please seek medical attention at the earliest opportunity possible However for uncomplicated measles adequate bed rest and medication but this may not be the case if complications begin

There are diseases that are as a result of acute measles being e.g. pneumonia, ear infections, acute measles encephalitis which is treatable in most cases with use of antibiotics in case of pneumonia which may result to sinusitis and bronchitis

Medicine that can be used can be ibuprofen(paracetamol) to reduce fever and pain whilst in children aspirin may be administered whereby medical advice may not be required which may result to Reye's syndrome. Though it has not been proven yet, trials have been done to determine whether vitamin a is a viable treatment but there has been no significant reduction in overall mortality. [3]

EPIDEMOLOGY

World health organization statistics has shown that measles has been a leading cause of fatalities especially children and those who have not been vaccinated earlier in life but due to aggressive campaign by governments and nongovernmental organizations vaccinations have been made possible that fatality rates have been reduced i.e. through organizations such as the United Nations, Unicef, Center for Disease and control

Statistically measles has reduced by 60% i.e. 873000-345000 in 2005 in 2008, the rates fell to 164000 and more of these found in South Asia Targets have been set in some areas set to fully eliminate measles by 2015 where 95% should be done with. [4]

IMPACT ON POPULATION AND OTHER RAMIFICATIONS

Measles is a common disease in all countries whether developed countries and developing third world countries but the only difference is that it is better managed in developed countries than developed countries. In developing countries due to huge populations epidemics are usually reported every 3-7 years but due to increasing populations of indigenous origin there is a sustained occurrence of the epidemics usually in the late springs which seizes before the end of spring while maternal antibodies boost the immunization efforts since protects infants during the first few months of birth. This overall methods has reduced infant mortality rate and also increased life expectancy amongst adults those has increased the overall quality health of the population and hence the productivity of the nation

COMPARISON AND CONTRASTING

Rubella caused by the rubella virus which translated means little red normally mild attacks that are often unnoticed and lasts only for 3-5 days but if not adequately managed may cause arthropathy in adults. However serious discomforts may not be common normally of the acquired type or the transmittable type through airborne causes faeces, urine and the skin

Congenital rubella syndrome normally occurs in the foetus of a pregnant woman in the first three months of her pregnancy .However chances of the foetus being affected may vary whereby there is 43% chance of being affected if occurs between 0-30 days of pregnsncy.0-12 weeks 51%chance, 14-28 weeks 23% chance but not generally affected if in the first 4 months of pregnancy. Chronic symptoms are reported if between 20 weeks of gestation and continue to disseminate the virus after birth

Measles is the same as the rubeola measles which as earlier stated affects the respiratory system spread through respiration, contact with fluids of infected person especially during sexual contact and also through aerosol transmission

The similarities between rubella and rubeola and congenital syndrome is that they are both diseases of the respiratory system and they are normally transmitted through similar methods i.e. aerosol transmission contact with fluids of an infected person. They are normally mild diseases and can be managed by antibiotics and adequate rest and can be chronic if not managed early in adults whereby the rubella measles may develop to transient artroparthy while in children it may develop to congenital rubella syndrome It would be prudent to note that in cases of rubella and rubeola measles there are presence of rashes that disappear within the first few days of diagnostics

The difference is that apart from the rest the congenital syndrome occurs only in children while the rest happens in both adults and children Congenital is normally a development of the rubella measles once the mother is infected within the first 20 weeks of pregnancy which characterize a series of incurable diseases and may lead to spontaneous abortion however unlike the earlier forms of measles it is not transmittable through aerosol transmission [6]

WORK CITED

1. Merriam-webster: Rubeola. Retrieved 2011-02-28

2. Samal, SK (editor) .The Biology of Paramyxoviruses.Caister Academic Press

3 .NHS UK: Symptoms of measles. Last reviewed: 26/01/2010

4. WHO Weekly EpidemiologyRecord, 4th December 2009

5.Assaad,F.Measles:summary of worldwide impact.US National library of medicine National institute of Health:1983

6. Siegel M, Fuerst HT, Guinee VF . "Rubella epidemicity and embryopathy. Results of a long-term prospective study". Am. J. Dis. Child.1971 121 (6): 469-73.

Writing Services

Essay Writing
Service

Find out how the very best essay writing service can help you accomplish more and achieve higher marks today.

Assignment Writing Service

From complicated assignments to tricky tasks, our experts can tackle virtually any question thrown at them.

Dissertation Writing Service

A dissertation (also known as a thesis or research project) is probably the most important piece of work for any student! From full dissertations to individual chapters, we’re on hand to support you.

Coursework Writing Service

Our expert qualified writers can help you get your coursework right first time, every time.

Dissertation Proposal Service

The first step to completing a dissertation is to create a proposal that talks about what you wish to do. Our experts can design suitable methodologies - perfect to help you get started with a dissertation.

Report Writing
Service

Reports for any audience. Perfectly structured, professionally written, and tailored to suit your exact requirements.

Essay Skeleton Answer Service

If you’re just looking for some help to get started on an essay, our outline service provides you with a perfect essay plan.

Marking & Proofreading Service

Not sure if your work is hitting the mark? Struggling to get feedback from your lecturer? Our premium marking service was created just for you - get the feedback you deserve now.

Exam Revision
Service

Exams can be one of the most stressful experiences you’ll ever have! Revision is key, and we’re here to help. With custom created revision notes and exam answers, you’ll never feel underprepared again.