Measles* Mumps* Rubella* Coxsackie A and B* Influenza virus* Rabies virus* Yellow fever virus* SARS* Dengue fever virus West Nile virus Polio virus

1. RNA viruses
Measles*
Mumps*
Rubella*
Coxsackie A and B*
Influenza virus*
Rabies virus*
Yellow fever virus*
SARS*
Dengue fever virus
West Nile virus
Polio virus

2. Cough , coryza ,
conjunctivitis (3 C’s) and rash

3. Measles : clinical
Koplik's spots : White
spots on red oral
mucosa near the
opening of Stensen
duct.
Look like “grains of
salt”
pathognomonic for
measles
Koplik's spots

4. Measles (Rubeola)
Measles: leading cause of vaccine preventable
death and illness.
The virus is trnasmitted by inhalation of
infective droplets.
Measles is clinically characterized by:
Fever,
Cough, coryza and conjunctivitis (3 C’s).
Mucosal lesions k/a Koplik’s spots and
Rash:
Starts on face and spreads to trunk and
extremities.
Disappears in the same order.

5. Complications
Otitis media
Measles pneumonia (giant cell pneumonia)
Warthin-Finkeldey giant cells in lung
=multinucleated giant cells
Pathognomonic for measles
Subacute Sclerosing Panencephalitis (SSPE)***
Rare but serious complication in
immunocompromised individuals

6. Measles giant cells
(Warthin-Finkeldey Giant Cells)

7. Swelling parotid
gland

8. Mumps
Clinically, mumps defined as
acute unilateral or bilateral parotid gland
swelling that lasts for more than two days
with no other apparent cause.
Mumps virus infects salivary gland ductal
epithelial cells
leading to classic signs of mumps :
Parotid gland swelling and pain.
Other features include:
Fever, malaise, headaches
This virus can also spread to other sites:
CNS  aseptic meningitis***
Testis and ovary  orchitis/ oophoritis
Pancreas  pancreatitis

9. Complications
Aseptic meningitis
most common complication** (50% of cases)
CSF findings:
mimics bacterial meningitis
low glucose, high protein, mixed
inflammatory reaction.
neutrophils in first 24 hours; then
lymphocytes
Others:
Orchitis /oophoritis, pancreatitis.
Laboratory diagnosis:
Elevated Serum amylase (salivary gland
inflammation and pancreatitis)

10. Rubella (German Measles)
Also known as 3 day measles.
A mild disease in children and adults; usually
associated with rash.
In pregnant women: rubella is destructive fetal
pathogen.
Children and adults: present with:
painful post auricular and occipital
lymphadenopathy (very characteristic).
fever, arthralgia, and
Rash: begins on head and spreads downward
lasts 3 days
No 3 C’s of Measles

11. Face of adult with
rubella.
Rash of rubella on skin of
child's back

12. Congenital Rubella
Part of the TORCH complex of diseases.
Maternal infection during first 8 weeks  high
incidence of congenital anomalies.
Transmission: Transplacental
Clinical findings:
Hearing loss (nerve deafness) **
most common defect.
Congenital heart defects:
PDA
Neurologic problems
mental retardation, microcephaly**
Ophthalmic problems
Cataract**,retinopathy, microphthalmia

13. Rash of congenital rubellaCongenital cataract

14. Case
CC
A 25 year old white male complains of shortness of
breath and ankle edema.
HPI
He also complains of fatigue & chest pain. His
symptoms followed a severe upper respiratory
infection.
PE
Tachycardia, hypotension, low-grade fever, jugular
venous pressure raised; pitting pedal edema; fine
inspiratory rales at both lung bases; mild
hepatosplenomegaly.
Imaging
CXR: Cardiomegaly and pulmonary edema.
Echo: dilated cardiomyopathy with low ejection
fraction

15. Coxsackie virus

16. Coxsackie virus
Type A : clinical manifestations
Hand-foot-mouth disease*
Herpangina
Aseptic meningitis
Acute hemorrhagic conjunctivitis
Type B: clinical manifestations
Myocarditis *
Pleurodynia (Bornholm’s Disease)
Aseptic meningitis

17. Hand, foot and mouth disease
Caused by Coxsackie type A16.
C/F include:
Ulcer: back of mouth and
Red rash: palm and soles
MC complication: dehydration

18. Myocarditis
Results when myocardium becomes infected.
MCC is Coxsackie virus B (also caused by
adenovirus)
Clinical findings:
Fever, chest pain, cyanosis, tachycardia
, cardiomegaly, EKG changes and
arrhythmia.
May result in cardiac failure.

19. Coxsackie Myocarditis
Lymphocytic infiltrates

20. Influenza virus
Influenza: acute, self limited infection of the
upper airways caused by strains of Influenza
virus
Three types of influenza virus A,B and C.
Type A virus : MC pathogen, causes
pandemics and epidemics (most severe form);
infects humans, pigs and horses.
Type B : epidemics
Type C: sporadic cases

21. Influenza virus
Influenza viruses have envelopes containing hemagglutinin
and neuraminidase.
Hemagglutinin : aids in attachment
Neuraminidase: dissolves mucus and facilitates release
of viral particles from infected cells.
The virus capable of altering its surface antigen:
Antigenic drifts:
point mutations resulting in change of antigenecity
of organism
Results in local epidemics.
Antigenic shifts:
involves replacement of H and Neur. through
recombination of RNA segments with those of
animal viruses.
Results in pandemics
New vaccine needed

22. Pathogenesis and disease
Spread
person to person via small particle aerosols
Site of infection
Epithelial cells of the respiratory tract
results in Cell death.
As a result, the efficiency of ciliary clearance
is reduced
Predisposition to secondary bacterial
infections

23. Influenza
Clinical findings:
Fever, chills, myalgia, headache and
nonproductive cough.
Complications:
1. Superimposed bacterial infections
Pneumonia
most common organism: Staph. aureus
2. Reye’s syndrome

24. Rabies
Transmitted to humans by bite of :
skunks, foxes, bats, raccoons, dogs
skunks most common source in U.S.
dog bite most common source in other
countries
May also be contracted by aerosol (bat
caves)
Results in severe encephalitis with increased
excitability of CNS

25. Virus enters CNS by ascending along peripheral
nerves from the wound site.
Initial manifestation:
fever, headache,parasthesias around wound
site .
CNS disease:
Chr by violent muscle contractions and
convulsions following minimal stimuli.
painful spasms of laryngeal and pharyngeal
muscles, frothing at the mouth, hydrophobia
followed by flaccid paralysis, coma, and
respiratory center paralysis.

26. Morphology
Microscopically characterized by
intracytoplasmic eosinophilic inclusions
Negri bodies in the neurons
Pathognomonic

27. Neuron without
Negri bodies
Negri body in
infected neuron

28. Other RNA viruses
Yellow fever:
C/F: Hepatitis, jaundice, fever, black vomitus
Histological findings: characteristic midzonal
hepatocellular necrosis and apoptotic liver cells
(Councilman bodies).
SARS virus:
First appeared in November of 2002 in Guangdong
province of China.
First transmitted to humans through wild masked palm
civets.
infects lower respiratory tract.
may resolve or progress to severe respiratory
disease.

29. Virus Disease
Measles virus* Measles
Mumps virus* Mumps
Rubella virus* Rubella
Coxsackie A and B* Myocarditis
Polio virus Poliomyelitis
Influenza virus* Influenza
SARS Respiratory disease
Dengue fever virus DF, DHF, DSS
Yellow fever virus Yellow fever
Arbo & and WestNile virus Encephalitis
Rabies virus* Rabies
Important RNA viruses