1. Paramyxoviruses

2. pathogenic paramyxoviruses
Measles virus
Parainfluenza viruses
Mumps virus
Respiratory syncytial virus,RSV

3. paramyxoviruses
Spherical ,enveloped, 150~300nm in diameter
helical nucleocapsid
-ssRNA as a single piece
Membrane fusion leads to the formation of syncytia
Envelope contains two glycoproteins, F protein and HN/H/G

4. PARAMYXOVIRUSES pleomorphic HN/H/G glycoprotein SPIKES F glycoprotein
helical nucleocapsid (RNA plus
NP protein)
lipid bilayer membrane
polymerase
(2 proteins)
M protein

5. Measles virus

6. HA,HL
Multinucleated giant cell
syncitia

7. Pathogenicity and immunity
There are only one serotype of virus
Measles is an acute febrile illness,mostly in childhood
Incubation period:10-12 days
Two viraemia
High fever,photophobia

8. conjunctivitis, rhinitis, cough---three main prodrome
Koplik’s spots
Maculopapular rash---T cell-mediated immunopathological mechanism
Rash fades with considerable desquamation

10. MEASLES - Koplik’s spots

11.                                                      
CDC - B.Rice

12. MEASLES - RASH
CDC - B.Rice

13. Recovery--- T cell response
T cell deficient, may be no rash, may be severe disease (life threatening)
Life-long immunity (protective antibody)

14. High risk factors vitamin A deficient low mucosal defense
malnourishment impaired immunity
Immunocompromised
Adults infection
Poor medical care
lack of vaccination
poor hygiene

15. Mims et al., Medical Microbiology 1993

16. Complications pneumonia due to secondary bacterial infection
Measles encephalitis
SSPE

17. Laboratory diagnosis Most cases of measles are diagnosed clinically
Virus isolation
Serodiagnosis
ELISA,HI,CF
Immunofluorescence assay

18. Epidemiology Human are only natural host
Transmission is person-to-person by respiratory droplet
Most contagious before rash is evident
Almost all infected individuals show disease
Natural infection and vaccine using give life long protection

19. Prevent and treatment Live attenuated vaccine
Can cause problems in immunosuppressed
Immune serum globulin
Supportive care

20. Mumps virus

21. There is only one serotype.
Mumps is a world-wide disease,with humans the only known reservior.
Most infections are in school-age children.
Mumps are often subclinical.

22. The incubation period is 14-18 days.
usually “flu-like” illness,with fever and malaise
parotid pain and swelling over a period of 1 to 3 days. The pain gets worse when the child swallows, talks, chews, or drinks acidic juices (like orange juice).

23. Clinical meningitis remains the most serious complication of mumps,occurring in 1-10% of patients with mumps parotitis.
postpubertal males --- orchitis
Oophoritis also occurs in girls

25. Infection appears to confer life-long immunity and second infections do not occur.
Typical mumps does not usually require laboratory confirmation.
Mumps live attenuated virus

26. Parainfluenza viruses

27. There are four types of parainfluenza viruses.
The viruses may cause minor upper respiratory tract illness,as well as tracheitis,laryngitis,bronchiolitis and pneumonia.
Local infection and no viraemia.
Fatalities are rare and reinfections occur

28. Respiratory syncytial virus(RSV)

29. The most serious illness caused by RS virus is bronchiolitis in young babies,especially in those under 1 year of year.

30. This infection is potentially life-threatening, particularly in those with bronchopulmonary dysplasia or congenital heart defects.
In older children and adults,the virus causes only minor infections
RS virus causes a substantial winter epidemic every year.
No vaccines have proved satisfactory.

31. Rhinovirus The most frequent of all human infections Piconaviridae
Spherical, non-enveloped,+ssRNA
Acid lability(complete inactivation at Ph 3.0)
Over 100 serotypes

32. The typical illness is a generally referred to as a common cold.
Infections provoke poor response and reinfections are very common.

33. Rubella virus glycoprotein icosahedral nucleocapsid
RNA (single-stranded positive-sense)
lipid bilayer membrane

34. Rubella virus(German measles)
Biological characters
Togaviridae
Spherical, 50-70nm
+ssRNA, enveloped
Icosahedral symmetry
One serotype

35. Pathogenicity and immunity
Infection is common in childhood
Infection in the upper respiratory tract
viraemia the target organs such as skin and joints

36. Pathogenicity and immunity
Incubation period:2-3 weeks
Fever, cough, arthritis
The characteristic feature is a macular rash and lymphadenopathy

37. Pathogenicity and immunity
Complications:encephalitis and
thrombocytopenia
High risk factor: pregnancy infection
during the first trimester congenital rubella
Life-long lasting immunity after infection

39. Rubella rash

40. Congenital rubella Congenital rubella symdrome Hearing loss
Congenital heart defects
Neurological
Psychomotor and/or mental retardation
Ophthalmic
cataract, glaucoma, retinopathy

41. Congenital rubella
The risk to the fetus depends on the gestational period.
First trimester
65-85% of neonates have sequelae
Reinfection in pregnant women leads little effect on fetus.

42. Prevention Live attenuated vaccine Susceptible non-pregnant females
In UK , MMR vaccine to all children at 15 months of age

43. Adenovirus

44. Named from their original source,
adenoid tissue
Human adenoviruses are subdivided into 6 subgenera (A-F) and 49 recognized serotypes.

45. Biological character
A single piece of dsDNA ,non-enveloped,70-90nm in diameter
A very good example of an icosahedron
apical fiber projects from each pentron
function: type-specific
haemagglutination(monkey or rat erythrocytes)
Experimentally induce transformation of hamster cells in culture.But there is no evidence that this can occur in humans.

48. Pathogenicity
Respiratory disease
conjunctivitis
gut infections

49. Treatment and control
No satisfactory vaccine
No antiviral drugs