Parainluenza virus causes Respiratory infection in young • They are the second most common cause of lower respiratory tract infection in younger children. Together, the Parainfluenza viruses cause ~75% of the cases of Croup. • Repeated infection throughout the life of the host is not uncommon. Symptoms of later breakouts include upper respiratory tract illness as in a cold and sore throat. The incubation period of all four serotypes is 1 to 7 days.
Morphology – Parainfluenza • HPIVs are negative-sense, single-stranded RNA viruses that possess fusion and hem agglutinin-neuraminidase glycoprotein "spikes" on their surface. There are four serotypes types of HPIV (1 through 4) and two subtypes (4a and 4b).
Para Influenza Viruses types • Four Types are present. • Type 1 Sendai Virus • Type 2 Acute Laryngo tracheo bronchitis. • Type 3 Respiratory infection in children • Type 4 Respiratory infection.
There are four serotypes in Paramyxoviridiae • HPIV-1 (most common cause of croup; also other upper and lower respiratory tract illnesses typical) • HPIV-2 (causes croup and other upper and lower respiratory tract illnesses) • HPIV-3 (associated with bronchiolitis and pneumonia) • HPIV-4 (includes subtypes 4a and 4b)
Present with Respiratory illness • The most distinctive clinical feature of HPIV-1 and HPIV-2 is croup (i.e., laryngotracheobronchitis); HPIV-1 is the leading cause of croup in children, whereas HPIV-2 is less frequently detected. Both HPIV-1 and -2 can cause other upper and lower respiratory tract illnesses.
Survive short period in the environment • The Virion varies in size (average diameter between 150 and 300 nm) and shape, is unstable in the environment (surviving a few hours on environmental surfaces), and is readily inactivated with soap and water.
Viral adoption and pathogenesis. • 150-300 nm in size. • Envelop Two Glycoprotein • G protein attaches to cell surfaces, • F protein causes cell to cell fusion. • No Hemagglutinins or Neuraminidase activity. • Grows in Human cell cultures He la and He p2.
Parainfluenza infections spread through respiratory tract • HPIV infection is acquired through inhalation of infected droplet nuclei or indirectly through contact with infected secretions. The incubation period is generally 2-6 days. See
Mechanisims of pathogenesis in Paramyxoviridiae • HPIV infection in the respiratory tract leads to secretion of high levels of inflammatory cytokines such as interferon (IFN)–alpha, interleukin (IL)–2, IL-6, and tumor necrosis factor (TNF)–alpha. The peak duration of secretion is 7-10 days after initial exposure. Increasing levels of certain chemokines such as RANTES (regulated upon activation, normal T-cell expressed and secreted), macrophage inflammatory protein (MIP)–K are detected in the nasal secretion of paediatric patients
Clinical Features • 10% of the respiratory infections are caused • CROUP – LRI, Bronchitis, Bronchiolitis, • Pneumonia. • Minor reparatory tract infections,
Children present with acute Respiratory infections • A broad range of findings is observed and may include fever, nasal congestion, pharyngeal erythema, non-productive to minimally productive cough, inspiratory stridor, rhonchi, rales, and wheezing.
Clinical Features • Respiratory illness, • Febrile Rhino rhea, • Tracheo Bronchitis, • Pneumonia. • Immune deficient High Mortality. • Otitis Media • Sudden Death Syndrome.
Upper and Lower respiratory tract infection major manifestation • Other infections: HPIVs routinely cause otitis media, Pharyngitis, and conjunctivitis coryza, and these can occur singly or in combination with a lower respiratory tract infection. HPIV-3 is the most frequently reported HPIV associated with Otitis media
Parainluenza infection in Immunosupressed Immunosuppresed people, such as transplant patients, Parainfluenza virus infections can cause severe pneumonia, which is often fatal
Epidemiology • Common between 6 weeks to 6 months. • Close contacts. • Contaminated fingers, • Fomites, • IgA A important in Immunity.
Reinfections in Parainfluenza • Parainfluenza infections do not confer complete protective immunity; therefore, Reinfections can occur with all serotypes and at any age, but Reinfections usually cause a mild illness limited to the upper respiratory tract.
Laboratory Diagnosis • Nasopharyngeal Swabs • Nasal washings • IMF techniques, • ELISA CF.
Infection with HPIVs can be confirmed with .. • 1) by isolation and identification of the virus in cell culture or by direct detection of the virus in respiratory secretions (usually, collected within one week of onset of symptoms) using immunofluorescence, enzyme immunoassay, or polymerase chin reaction assay,
Infection with HPIVs can be confirmed with serology • 2) by demonstration of a significant rise in specific IgG antibodies between appropriately collected paired serum specimens or specific IgM antibodies in a single serum specimen.
Maternal antibodies protect first few months • Passively acquired maternal antibodies may play a role in protection from HPIV types 1 and 2 in the first few months of life, highlighting the importance of breast-feeding..
Hand Washing can reduce the infection rates • Frequent hand washing and not sharing items such as cups, glasses, and utensils with an infected person should decrease the spread of virus to others.
Prevention of Spread in Hospitals • In a hospital setting, spread of HPIV’s can and should be prevented by strict attention to contact precautions, such as hand washing and wearing of protective gowns and gloves
Treatment and Prophylaxis. • Treatment with Ribavirin • No Vaccine to date.
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