Virology ppt

1. Paramyxovirus – mumps, parainfluenza,
Morbillivirus – measles
Togavirus-Rubellavirus
Pneumovirus - respiratory syncytial virus
PARAMYXOVIRIDAE
BY
DR EILU EMMANUEL

2. • These include important agents of respiratory
infections of infants and young children i.e.
parainfluenza viruses, respiratory syncytial virus,
mumps and measles.
• The properties of the viruses are similar to
orthomyxovirus with minor differences. However,
paramyxoviruses are antigenically stable.

3. PARAINFLUENZA VIRUS
• It is a major cause of respiratory disease in
infants and young adults.
• Infection is transmitted by droplets.
• The virus multiplies locally.
• Incubation period is 2-6 days.

4. • The primary infection usually results in rhinitis
and pharyngitis often with fever and bronchitis.
• However, the infection may cause sever illness,
ranging from laryngotracheobronchitis(croup) to
pneumonia.
• Diagnosis; as in influenza.
• Prophylaxis: No prophylaxis is available.

5. RESPIRATORY SYNCYTIAL VIRUS (RSV
• It is the most important cause of respiratory
disease in infants and children.
• In adults it causes a mild upper respiratory
infection.
• Outbreaks may occur in hospitalized infants,
debilitated or elderly patients. Infection is
transmitted by droplets and close contact.

6. • Diagnosis as in influenza, however, rapid
diagnosis is required since serious
infections in infants should be treated to
avoid residual affection of pulmonary
functions later in life.
• Rapid diagnostic kits for antigen detection
in respiratory secretions are commercially
available

7. • Treatment:
• Aerosolized ribavirin is used for treatment
of infants with serious RSV.
• It may be combined with specific
hyperimmune globulins.

8. • Prevention:
• There is no vaccine.
• An inactivated vaccine prepared and used in
1960 resulted in an increase in severity of
symptoms.
• Monoclonal antibodies against viral
components or hyperimmune globulins can be
used for prophylaxis of premature or
immunocompromised infants.

9. MUMPS
• It is an acute contagious disease characterized
by non-suppurative enlargement of the parotid
glands.
• The virus exists as one antigenic type.

10. • Pathogenesis:
• Infection occurs by droplets or direct contact
with saliva or urine.
• Primary multiplication occurs in the
respiratory mucosa followed by viraemia and
localization of virus in the parotidsand salivary
glands.
• It may affect the testes, ovaries, pancreas and
the CNS.
• One third of cases are subclinical.

11. • The incubation period is 18 days followed by fever,
malaise, anorexia and swelling of parotid glands.
• The disease is benign and resolves spontaneously.
Orchitis rarely occurs and may lead to sterility.
Meningo-encephalitis may complicate some cases
and it usually resolves without sequelae. Pancreatitis
is a rare complication.
• Immunity is permanent after a single infection.
Infants are immune for the first 6 months due to
maternal antibodies.

12. • Diagnosis:
• Isolation of the virus from saliva, CSF, or
urine by culture on monkey kidney cells.
• Detection of a rising antibody titre by
orhaemagglutination inhibition. ELISA is
used to detect IgM antibodies.

13. • Prophylaxis:
• A living attenuated vaccine is given
to children at the age of 15 months.
• A single dose given subcutaneously
gives immunity for 10 years.
• It may be combined with measles
and rubella (MMR) vaccines.

14. MEASLES
• Measles is a highly infectious disease that
affects children.
• It is characterized by fever and
maculopapular skin rash.
• There is only one type of measles virus and
man is the only host.

15. • Pathogenesis:
• Infection occurs by droplets.
• Primary multiplication occurs in the
respiratory mucosa from where it passes to
the regional lymph nodes and the reticulo-
endothelial system to pour in the blood
causing viraemia then it localizes in the skin
and mucous membrane.

16. • Incubation period is 10 days followed
by fever which lasts for 4 days
associated with conjunctivitis, cough
and "koplik's spots" in the mouth.
• These are red spots with bluish-white
centre in the buccal mucosa opposite
the lower molars.
As the fever subsides the
maculopapular rash appears all over
the body.

17. • Complications may occur in
debilitated children e.g. otitis media,
bronchopneumonia and rarely
encephalitis.
• One attack of measles is followed by
long lasting immunity.
• Infants are immune for the first 6
months due to maternal antibodies.

18. • Diagnosis: Measles is easy to diagnose
clinically.
• Laboratory diagnosis is rarely needed.

19. • Prophylaxis:
• A living attenuated vaccine is given in
one injection to children at the age of
15 months.
• It may be given in combination with
mumps and rubella (MMR) vaccines.
• Another dose is recommended before
school entry.

20. RUBELLA GERMAN MEASLES
• Rubella is an acute infectious disease
characterized by fever, rash and enlargement
of occipital and cervical lymph nodes.

21. • Rubella virus belongs to the
Togavirus family.
• However, it is not transmitted by
arthropods.
• It is a single stranded positive
sense RNA, icosahedral,
enveloped virus.
• It is one antigenic type and is
haemagglutinating.
• It causes two types of infections:

22. Postnatal rubella:
• Infection of neonates, children and
adults occurs by droplets.
• Incubation period is 2-3 weeks.
• After primary multiplication in the
upper respiratory mucosa and
viraemia develops towards end of inc
period.

23. • Maculopapular rash appears associated
with enlargement of the postauriculr and
suboccipital lymph nodes and respiratory
manifestations.
• The disease is mild and self limited and one
attack is followed by solid immunity.

24. Congenital Rubella Syndrome:
• Rubella infection of pregnant women results in
transplacental transmission of the virus and
infection of the foetus.

25. • If this happens during the first trimester of
pregnancy, during which time the very
sensitive organs develop, it may lead to
congenital anomalies of the baby in the
form of congenital heart defects,
deafness, blindness, mental retardation
and hepato- splenomegaly.

26. • This is known as the "congenital rubella
syndrome".
• Infection may lead to intrauterine foetal
death and abortion.

27. • Children infected in utero can continue to
excrete the virus for up to 18 months after
birth.
• The virus is found in pharyngeal secretions
and other body fluids.
• They can be a source of infection to
pregnant women.

28. • The problem is more serious when such
chronic shedders are asymptomatic and
without malformations.
• They can be diagnosed only by isolation of
the virus or by the detection of IgM or a
rising IgG titre.

29. Diagnosis:
• - Detection of a rising titre of rubella IgG in
paired serum samples separated by 10 days,
or detection of rubella IgM antibodies in a
single serum sample in pregnant women is
diagnostic of recent rubella infection.
• This is an indication for therapeutic abortion
specially during the first trimester of
pregnancy.

30. • If recent infection has occurred, isolation of virus from
amniotic fluid during pregnancy indicates definite
foetal infection.
• -Detection of rubella IgM antibodies in the newborn is
diagnostic of infection in utero.
• IgM does not cross the placenta, so their presence
indicates that they must have been synthesized by
the infant in utero.
• Isolation of virus from newborn specimens may be
used for diagnosis.

31. Prophylaxis:
• A living attenuated rubella vaccine is available
alone or in combination with measles and
mumps (MMR) vaccines.
• It is given in a single injection.
• The MMR vaccine is given to children at the
age of 15 months.
• Another dose is recommended as for measles
before entering school.

32. • The single vaccine is recommended for girls
before marriage, and for sero-negative
women after delivery.

33. • Vaccination should be avoided during pregnancy
and for 3 months before getting pregnant.
• A proof of immunity (positive serologic tests or
documented rubella vaccination) is required for
women entering college and for female hospital
personnel who might come in contact with
rubella patients or pregnant women.