paramyxovirus net
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Dr.T.V.Rao MD 1
Parainluenza virusDr.T.V.Rao MD
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Parainluenza virus causes Respiratory infection in
youngThey are the second most common cause of lower respiratory tract infection in younger children. Together, the Parainluenza 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.
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Virus Properties.150-300 nm in size.
Envelop Two Glycoprotein
G protein attaches to cell surfaces,
F protein causes cell to cell fusion.
No Haemagglutinnins or Neuraminidase activity.
Grows in Human cell cultures He la and He p2.
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.
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ETIOLOGY:
Parainluenza viruses are enveloped RNA viruses classified as paramyxoviruses. Four antigenically distinct types—1, 2, 3, and 4 (with 2 subtypes, 4A and 4B )
Morphology – Parainluenza
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).
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VirionThe 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.
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There are four serotypes in Parmyxoviridae
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)
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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.
Parainluenza 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.
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Mechanisms of pathogenesis in Parmyxoviridae
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 tumour necrosis factor (TNF)–alpha. The peak duration of secretion is 7-10 days after initial exposure.
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Mechanisms of pathogenesis in Parmyxoviridae
Increasing levels of certain chemokine's 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
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..
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Clinical Features10% of the respiratory infections are caused
CROUP – LRI, Bronchitis, Bronchiolitis,
Pneumonia.
Minor reparatory tract infections,
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Children present with Respiratory infectionsA 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.
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Clinical FeaturesRespiratory illness,
Febrile Rhino rhea,
Tracheo Bronchitis,
Pneumonia.Immune deficient High Mortality.
Otitis Media
Sudden Death Syndrome.
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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
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Parainluenza infection in Immunosuppressed
Immunosuppressed people, such as transplant patients, Parainluenza virus infections can cause severe pneumonia, which is often fatal
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Epidemiology
Common between 6 weeks to 6 months.
Close contacts.
Contaminated fingers,
Fomites,
IgA A important in Immunity.
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Reinfections in Parainluenza
Parainluenza 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.
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Laboratory Diagnosis
Nasopharyngeal Swabs
Nasal washings
IMF techniques,
ELISA CF.Dr.T.V.Rao MD21
Laboratory Diagnosis
Throat and Nasal Swabs
Cultured in ,
Monkey kidney and cell lines.
ELISA, CF,HI
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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,
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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.
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Hand Washing in 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.
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Treatment and Prophylaxis.
Treatment with Ribavirin
No Vaccine to date.
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