Parainfluenza Medical Assignment Help

Parainfluenza is caused by the parainfluenza viruses types I to IV, which have a worldwide distribution. Type IV has been identified only in the USA. Parainfluenza is essentially a disease of children and presents with features similar to the common cold. When severe, a brassy cough with inspiratory stridor and features of laryngotracheobronchitis (croup) are present. Treatment is symptomatic with oxygen, humidification and sedation when required. The role of steroids is controversial. Measles (rubeola) Measles is a highly communicable disease that occurs worldwide. With the introduction of aggressive immunization policies, the incidence of measles has fallen dramatically in the West, but it still remains one of the commonest childhood infections in the developing countries, where it is associated with a high morbidity and mortality. It is spread by droplet infection.

CLINICAL FEATURES

The incubation period varies from 8 to 14 days. Two distinct phases of the disease can be recognized.

Typical measles
1 The infectious pre-eruptive and catarrhal stage. This is the stage of viraemia and viral dissemination. Malaise, fever, rhinorrhoea, cough, conjunctival suffusion and the pathognomonic Koplik’s spots are present during this stage. Koplik’s spots are small, greyish, irregular lesions surrounded by an erythematous base and are found in greatest numbers on the mucous membrane opposite the second molar tooth. They occur a day or two before the onset of the rash. 2 The non-infectious eruptive or exanthematous  stage. This is characterized by the presence of a maculopapular rash that initially occurs on the face, chiefly the forehead,and then spreads rapidly to involve the rest of the body. At first the rash is discrete but later it may become confluent and patchy, especially on the face and neck. It fades in about 1 week and leaves behind a brownish discoloration with desquamation. Although measles is a relatively mild disease in the healthy child, it carries a high mortality in the malnourished and in those who have other diseases. Complications are common in such individuals and include bacterial pneumonia, bronchitis, otitis media and gastroenteritis. Less commonly, myocarditis, hepatitis and encephalomyelitis may occur. The virus has also been implicated in the rare condition subacute sclerosing pan encephalitis. Maternal measles, unlike rubella, does not cause congenital fetal abnormalities. It is, however, associated with spontaneous abortions and premature delivery.

Atypical measles

Atypical measles is a severe illness that usually occurs in individuals who have previously received an inactivated vaccine (now withdrawn) and are exposed to wild measles virus. The high fever (>40°C), myalgia, abdominal pain and cough are followed by vesicles, petechiae and purpura.  Skin lesions may be mistaken for scarlet fever, meningococcaemia or varicella. Pneumonia invariably occurs and the pulmonary infiltrates may persist for years.

DIAGNOSIS

Immunofluorescence, virus culture and serological tests (complement fixation test (CFT), haemagglutination inhibition tests) are used to confirm the diagnosis.

TREATMENT

Treatment is symptomatic. Antibiotics are indicated only if secondary bacterial infection occurs.

PREVENTION

A previous attack of measles confers a high degree of immunity and second attacks are uncommon. Human immunoglobulin 0.25 ml kg-I given within 5 days of exposure effectively aborts an attack of measles. It is indicated for previously unimmunized children below 3 years of age, during pregnancy, and in those with debilitating disease. Active immunization involves a single dose of 0.5 ml live attenuated measles vaccine given subcutaneously (see Information box 1.2). Children are now immunized with the combined mumps, measles, rubella vaccine (MMR).

Mumps

Mumps is the result of infection with a paramyxovirus. It is spread by droplet infection, by direct contact or through fomites. Humans are the only known natural hosts. The peak period of infectivity is 2-3 days before the onset of the parotitis and for 3 days afterwards.

CLINICAL FEATURES

The incubation period averages 18 days. Although no age is exempt, it is primarily a disease of school-aged children and young adults; it is uncommon before the age of 2 years. The prodromal symptoms are non-specific and include fever, malaise, headache and anorexia. This is usually followed by severe pain over the parotid glands, with either unilateral or bilateral parotid swelling. The enlarged parotid glands obscure the angle of the mandible and may elevate the ear lobe, which does not occur incervical lymph node enlargement. Trismus due to pain is common at this stage. Submandibular gland involvement occurs less frequently.

COMPLICATIONS

CNS involvement is the commonest extra-salivary-gland manifestation of mumps. Clinical meningitis occurs in 5% of all infected patients, and 30% of patients with CN S involvement have no evidence of parotid gland involvement. Epididymo-orchitis develops in about one-third of patients who develop mumps after puberty. Bilateral testicular involvement results in sterility in only a small percentage of these patients. Pancreatitis, oophoritis, myocarditis, mastitis, hepatitis and polyarthritis may also occur.

DIAGNOSIS

The diagnosis of mumps is on the basis of the clinical features. In doubtful cases, serological demonstration of a fourfold rise in antibodies detected by complement fixationor indirect haemagglutination or neutralization tests on acute and convalescent sera is diagnostic. Virus  can be isolated in cell culture from saliva, throat swab, urine and CSF and identified by immunofluorescence or haemadsorption.

TREATMENT

Treatment is symptomatic. Attention should be given to adequate nutrition and mouth care. Analgesics should be used to relieve pain. The role of steroids in the treatment of mumps orchitis is controversial.

PREVENTION

Live attenuated mumps virus vaccine given as a single 0.5 ml intramuscular dose can prevent the disease in children over the age of 1 year. This vaccine should not beused in children below this age as it may be inhibited by  maternally acquired antibodies. Vaccination is contraindicated in immunosuppressed individuals, during pregnancy, or in those with severe febrile illnesses, because the live attenuated vaccine may cause disease. Respiratory syncytial virus infection Respiratory syncytial virus is a paramyxovirus that causes many respiratory infections in epidemics each winter. It is a common cause of bronchiolitis in infants, which is complicated by pneumonia in approximately 10% of cases. Immunity is short-lived and consequently reinfection can occur throughout life.

DIAGNOSIS

Immunofluorescence, virus culture and serology are the usual ways of confirming the diagnosis.

TREATMENT

Generally supportive, but aerosolized ribavirin can be given to severe cases. No vaccine is available.

RHABDOVIRUSES

Rabies
Rabies is a major problem in some countries and carries a high mortality. The rabies virus is bullet-shaped and has spike-like structures arising from its surface containing glycoproteins that cause the host to produce neutralizing, haernagglutination-inhibiting antibodies. The virus has a patients who develop mumps after puberty. Bilateral testicular involvement results in sterility in only a small percentage of these patients. Pancreatitis, oophoritis, myocarditis, mastitis, hepatitis and polyarthritis may also occur.

DIAGNOSIS

The diagnosis of mumps is on the basis of the clinical features. In doubtful cases, serological demonstration of a fourfold rise in antibodies detected by complement fixationor indirect haemagglutination or neutralization tests on acute and convalescent sera is diagnostic. Virus  can be isolated in cell culture from saliva, throat swab, urine and CSF and identified by immunofluorescence or haemadsorption.

TREATMENT

Treatment is symptomatic. Attention should be given to adequate nutrition and mouth care. Analgesics should be used to relieve pain. The role of steroids in the treatment of mumps orchitis is controversial.

PREVENTION

Live attenuated mumps virus vaccine given as a single 0.5 ml intramuscular dose can prevent the disease in children over the age of 1 year. This vaccine should not be used in children below this age as it may be inhibited by maternally acquired antibodies. Vaccination is contraindicated in immunosuppressed individuals, during pregnancy, or in those with severe febrile illnesses, because the live attenuated vaccine may cause disease.

Respiratory syncytial virus infection
Respiratory syncytial virus is a paramyxovirus that causes many respiratory infections in epidemics each winter. It is a common cause of bronchiolitis in infants, which is complicated by pneumonia in approximately 10% of cases. Immunity is short-lived and consequently reinfection can occur throughout life.

DIAGNOSIS

Immunofluorescence, virus culture and serology are the usual ways of confirming the diagnosis.

TREATMENT

Generally supportive, but aerosolized ribavirin can be given to severe cases. No vaccine is available.

RHABDOVIRUSES
Rabies
Rabies is a major problem in some countries and carries a high mortality. The rabies virus is bullet-shaped and has spike-like structures arising from its surface containing glycoproteins that cause the host to produce neutralizing, haernagglutination-inhibiting antibodies. The virus has a patients who develop mumps after puberty. Bilateral testicular involvement results in sterility in only a small percentage of these patients. Pancreatitis, oophoritis, myocarditis, mastitis, hepatitis and polyarthritis may also occur.

DIAGNOSIS

The diagnosis of mumps is on the basis of the clinical features. In doubtful cases, serological demonstration of a fourfold rise in antibodies detected by complement fixation or indirect haemagglutination or neutralizationtests on acute and convalescent sera is diagnostic. Virus can be isolated in cell culture from saliva, throat swab, urine and CSF and identified by immunofluorescence or haemadsorption.

TREATMENT

Treatment is symptomatic. Attention should be given to adequate nutrition and mouth care. Analgesics should be used to relieve pain. The role of steroids in the treatment of mumps orchitis is controversial.

REVENTION

Live attenuated mumps virus vaccine given as a single 0.5 ml intramuscular dose can prevent the disease in children over the age of 1 year. This vaccine should not be used in children below this age as it may be inhibited by maternally acquired antibodies. Vaccination is contraindicated in immunosuppressed individuals, during pregnancy,or in those with severe febrile illnesses, because the live attenuated vaccine may cause disease.

Respiratory syncytial virus infection

Respiratory syncytial virus is a paramyxovirus that causes many respiratory infections in epidemics each winter. It is a common cause of bronchiolitis in infants, which is complicated by pneumonia in approximately 10% of cases. Immunity is short-lived and consequently reinfection can occur throughout life.

DIAGNOSIS

Immunofluorescence, virus culture and serology are the usual ways of confirming the diagnosis.

TREATMENT

Generally supportive, but aerosolized ribavirin can be given to severe cases. No vaccine is available.

RHABDOVIRUSES
Rabies
Rabies is a major problem in some countries and carries a high mortality. The rabies virus is bullet-shaped and has spike-like structures arising from its surface containing glycoproteins that cause the host to produce neutralizing, haernagglutination-inhibiting antibodies. The virus has a marked affinity for nervous tissue and the salivary glands. It exists in two major epidemiological settings:

1Urban rabies, which is most frequently transmitted to humans through rabid dogs and, less frequently, cats. 2 Sylvan (wild) rabies, which is maintained in the wild by a host of animal reservoirs such as foxes, skunks, jackals, mongooses and bats. With the exception of Australia, New Zealand and the Antarctic, human rabies has been reported from all continents. Transmission is through the bite of an infected animal. However, the percentage of rabid bites leading to clinical disease ranges from 10% (on the legs) to 80% (on the head). Rabies has been transferred by corneal grafting but anecdotal reports of human-to-human spread by kissing, biting and sexual intercourse have not been confirmed. Rabid animals can also transmit the disease by licking abraded skin or mucosa. Rarely, airborne droplet infection occurs from exposure to infected bats in caves or in laboratory workers handling concentrated virus. Havin  entered the human body, the virus replicates in the muscle cells near the entry wound. It penetrates the nerve endings and travels in the axoplasm to the spinalcord and brain. In the eNS the virus again proliferates  before spreading to the salivary glands, lungs, kidneys and other organs via the autonomic nerves.

CLINICAL FEATURES

The incubation period is variable and may range from a few weeks to several years; on average it is 1-3 months. In general, bites on the head, face and neck have a shorter incubation period than those elsewhere. In humans, two distinct clinical varieties of rabies are recognized:
1 ‘Furious rabies’ -the classical variety
2 ‘Dumb rabies’ -the paralytic variety Furious rabies The only characteristic feature in the prodromal period is the presence of pain and tingling at the site of the initial wound. Fever, malaise and headache are also present. About 10 days later, marked anxiety and agitation or depressive features develop. Hallucinations, bizarre behaviour and paralysis may also occur. Hyperexcitability, the hallmark of this form of rabies, is precipitated by auditory or visual stimuli. Hydrophobia (fear of water) is present in 50% of patients and is due to severe pharyngeal spasms on attempting to eat or drink. Aerophobia (fear of air) is considered pathognomonic of rabies. Examination reveals hyperreflexia, spasticity, and evidence of sympathetic overactivity indicated by pupillary dilatation and diaphoresis.
The patient goes on to develop convulsions, respiratory paralysis and cardiac arrhythmias. Death usually occurs in 10-14 days. Dumb rabies Dumb rabies, or paralytic rabies, presents with a symmetrical ascending paralysis resembling the Guillain- Barre syndrome. This variety of rabies commonly occurs after bites from rabid bats. There have been only two recorded cases of survival from clinical rabies; with these exceptions, the disease has been uniformly fatal.

DIAGNOSIS

The diagnosis of rabies is generally made clinically. Recently, fluorescent antibody has been used to detect rabies antigen in corneal impressions or in salivary secretions; this is a useful test. The classical Negri bodies are detected at post mortem in 90% of all patients with rabies; these are eosinophilic, cytoplasmic, ovoid bodies, 2-10 nm in diameter, seen in greatest numbers in the cells of the hippocampus and the cerebellum.

TREATMENT

Once the disease is established, therapy is symptomatic. The patient should be nursed in a quiet, darkened room. Nutritional, respiratory and cardiovascular support may be necessary. Drugs such as morphine, diazepa and chlorpromazine should be used liberally in patients who are excitable.

PREVENTION

The vaccine IS the human diploid cell strain vaccine (HDCSV).

Postexposure prophylaxis

Five 1.0 ml doses of HDCSV should be given intramuscularly: the first dose is given on day 0 and is followed by injections on days 3, 7, 14 and 28. Reactions to the vaccine is uncommon. The wound should be carefully cleaned with soap and water, adequately debrided and left open. Antirabies serum injected locally around the site of the wound may be helpful. Pre-exposure prophylaxis This is given to individuals with a high risk of contracting rabies, e.g. laboratory workers, animal handlers and veterinarians. HDCSV 1.0 ml intramuscularly on days 0,7 and 21 should provide effective immunity. Vaccines of nervous- tissue origin are still used in some parts of the world. These, however, are associated with significant side-effects and are best avoided if HDCSV is available.

Posted by: brianna

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