Final Exam - Paramyxoviridae Flashcards
Paramyxoviridae
Causes rinderpest, canine distemper virus, Newcastle disease virus, Nipah, measles and mumps. Impact has been reduced from vaccination.
Two genera that come from Paramyxoviridae are:
- Avulavirus
2. Morbilivirus
3 membrane proteins
- Unglycosylated matrix protein (M)
- Fusion protein (F) glycosylate envelope protein
- Hemagglutinin (H) glycosylated envelope protein
3 nucleocapsid proteins
- RNA binding protein (N)
- Phosphoprotein (P)
- Large polymerase (L)
Antibodies directed against these proteins
Usually neutralizing antibodies - important in protection against paramyxovirus infection
Replication - Rubulaviruses, Respiroviruses and Avulaviruses
The HN molecule binds to sialic acid residue - either glycolipids or glycoproteins.
Replication - Morbiliviruses
The receptor is located on lymphocytes, dendritic cells or macrophages - CD150
Replication - Henipaviruses
The receptor is ephrin B2 and B3 cell surface proteins on endothelial cells or on brain stem neurons
Replication - Pneumoviruses
The receptor is heparan sulfate.
Paramyoviruses Inclusion Bodies
Cytoplasmic acidophilic inclusion bodies, composed of ribonucleoprotein structure
Newcastle Disease
A disease of chickens. 10 serotypes. Avian ParaMyxoViruses. APMV-1 to APMV-10. NDV = APMV-1.
Newcastle Disease - 5 Pathotypes
- Viscerotropic velogenic
- Neurotropic velogenic
- Mesogenic
- Lentogenic (respiratory)
- Asymptomatic
Newcastle Disease Hosts
Chickens are highly susceptible to disease. Turkeys do NOT develop severe signs.
Newcastle Disease Transmission
Direct contact with secretions of infected birds via ingestion and inhalation. Fomites feed, water, premises, human clothing, boots, sacks, egg trays/crates. Hatching chicks may be infected through the egg for some NDV strains.
Newcastle Disease Occurence
Velogenic NDV is endemic in areas of Mexico, Central and South America. In double crested wild cormorants in the US and Canada. Lentogenic strains of NDV are worldwide in their distribution.
Newcastle Disease Diagnosis
Clinical signs are rare. Clinical signs alone do not present a reliable basis for diagnosis of ND.
Lentogenic Strains
Usually associated with subclinical disease marked by mild respiratory symptoms; coughing, gasping, sneezing and rales. Morality is negligible.
Velogenic Strains
Cause severe disease in chickens with high mortality for unvaccinated chickens. Signs, principally respiratory and/or nervous. Initial clinical signs vary but include: lethargy, inappetence, ruffled feathers, edema. Greenish or white water diarrhea, dyspnoea and inflammation of the head and neck with cyanotic discoloration. Often result in death with few or no signs.