Paramyxovirus Flashcards
What are the general properties of Paramyxoviridae?
Negative sense ssRNA, non-segmented, helical nucleocapsid, enveloped with surface spikes: haemagglutinin, neuraminidase, and fusion protein varies according to species.
What are the four important human pathogens in the Paramyxovirus family?
Parainfluenza virus, Respiratory syncytial virus (RSV), Measles, and Mumps.
What diseases are caused by Human Parainfluenza Virus (HPIV)?
Croup (acute laryngotracheobronchitis), laryngitis, bronchiolitis, pneumonia in children, and common cold in adults.
What are the four serotypes of HPIV and their associated diseases?
Type 1 and 2 are major causes of croup. Type 3 is the most common type isolated from children with lower respiratory tract infection. Type 4 rarely causes disease except common cold.
What are the laboratory diagnosis methods for Parainfluenza virus?
Detection of Antigen: a rapid diagnosis can be made by the detection of parainfluenza antigen from nasopharyngeal aspirates and throat washings. Virus Isolation: virus may be readily isolated from nasopharyngeal aspirates and throat swabs. Serology: a retrospective diagnosis may be made by serology. CFT is most widely used.
What is the most important cause of bronchiolitis and pneumonia in infants under 1 year of age?
Respiratory syncytial virus (RSV).
What are the other diseases caused by RSV?
Common cold and bronchitis in older children, otitis media in young children, and pneumonia in the elderly.
What are the laboratory diagnosis methods for RSV?
Rapid antigen test (enzyme immunoassay), immunofluorescence on smear or culture, cytopathic effect (multinucleated giant cells), four-fold rise antibody titer, and RT-PCR.
What is the pathogenesis and immunity of Measles?
After infection of the respiratory lining, the virus enters the blood and infects reticuloendothelial cells (replicate again) then spread to skin. The rash is due to cytotoxic cells attacking endothelial cells of blood vessels in the skin. Antibody-mediated vasculitis may play a role. Immunity is lifelong.
What are the clinical findings of Measles?
IP: 10-14 days, prodromal phase (fever, coryza, cough, conjunctivitis), Koplik’s spot is diagnostic (bright red lesion with central white dot on the buccal mucosa), rash: maculopapular starting on the face proceeding gradually to the trunk and lower extremities including palms and soles.
What are the complications of Measles?
Pneumonia, otitis media, encephalitis (1 per 1000), subacute sclerosing panencephalitis (SSPE) is a late sequel, fetal death (stillbirth) rather than congenital malformation.
What is the prevention method for Measles?
Live attenuated vaccine given subcutaneously to children at 15 months (MMR). Should not be given to pregnant or immunocompromised individuals. Immunoglobulin can be used if the patient is not immunized and given early during the incubation period.
What are the clinical findings of Mumps?
IP: 18-21 days, prodromal stage (fever, malaise, anorexia), tender swelling of salivary gland (unilateral or bilateral), characteristic increase in pain with citrus juice, resolves spontaneously within 1 week.
What are the complications of Mumps?
Orchitis in post-pubertal males (if bilateral can cause sterility), meningitis (self-limited), pancreatitis, and encephalitis.
