Transcript SWINE INFLUENZA

Rabdovirus
 The virion is from Rabdoviridea family.
 Morphology: nucleocapside is like a bullet
 Genome: linear single stranded RNA,
Negative sense, M protein, RNA-dependent
RNA polymerase, Enveloped.
Disease: Rabies
 Several hosts including all warm-blooded
living things, especially in dog, wolf, fox,
bat.
 Human to human transmission is very rare.
 The virus can be found in nerve system,
saliva, urine, lymph, milk.
 There is only one serotype of rabies virus.
 Glycoprotein G is a main cause of virus
invading to nerve system.
Pathogenesis
 Virus amplification in muscles  nerve -
muscle synapses  virus entering into
peripheral nerves  central nerve system
 Attachment to Asetylcholin  entering
to the brain and multiplication 
progressive encephalitis  virus moving to
saliva glands and other organs like
pancreas, kidney, heart, retina, cornea,
through peripheral nerves.
Clinical findings
 Incubation period: 20 days to 2 months
(but seen between 1 week to 19 years)
depends to the age, genetic background,
race, the number of virus inoculated, the
distance of virus to central nerve system.
 Rabies is an accidental viral infection in
human.
 Clinical periods includes 3 stages:
I. Introductory short stage:
2-10 days: non-specific symptoms (headache,
photophobia, nausea, vomiting, sore throat,
fever, no appetite.
II.2-7 days: partial paralysis, cerebral
dysfunction, anxiety, sleeplessness,
confusion, agitation, abnormal behavior,
terror, hallucinations. Increased activity of
simpatico system such as increased tear
secretion, increased saliva, hydrophobia.
III. Coma and death
Lab diagnosis
 Negri bodies in brain or spinal cord
(spherical, 2-10 microns granules. They
contain rabies antigens and detectable by
immunoflorosence (IF) methods.
 Virus isolation in humestesr or mice cells.
 PCR
 Serologic methods (Detecting antibodies)
Prevention and treatment
 All infected animals should be killed and
their tissues should be tested in lab.
 Vaccination (inactivated virus) is used for
people who have been bitted or their job is
known as high risk carrier.
 Antibody (antiserum) prophylaxis.
 No treatment
Common cold viruses
Rinoviruses
Adenoviruses
Coronaviruses
Enteroviruses
Parainfluenza viruses
Influenza viruses
Rinoviruses
 The main cause of the common cold
 From Picornaviruses
 RNA single strand, + sense, The genome
includes a small viral Pr at 5’ end.
 No envelope
 Ichozahedral
 28-30 nm (as a small virus)
Important properties
- More than 100 serological types
- Replicate better at 33C than 37C (affecting
primarily nose and conjunctiva rather than
the lower respiratory tract).
- Acid-labile, so killed by gastric acid when
swallowed.
- The host range: humans and chimpanzees
Pathogenesis
 Entering through the upper respiratory tract
 There is a correlation between the
concentration of viruses in nasal dischargse
(or mucosa) and the severity of disease.
 The viruses are usually seen in 2-4 days
after infection.
 Some times virus still is detectable by 3
weeks.
 The virus spread is limited to the epithelial
surface of nasal mucosa.
 Histopathology changes are limited to the
surface of epithelium and includes: Edema
and low penetration of cells.
 Cold weather does not cause common cold
or even not increase the chance for it.
Clinical finding
 Incubation period: 2-4 days
 Acute stage: sometimes to 7 days but dried
cough can last by 2-3 weeks.
 Adults: 1-2 cold onset per year.
 Symptoms: sneeze. sore throat. chill, some
times low fever, nasal congestion and loss
of smell.

Clinical finding
 There is no way to distinguish common
cold caused by rinoviruses from common
colds by others viruses.
 Bacterial secondary infection: otitis,
sinusitis, bronchitis, pneumonia.
Immunity
 Antibody appearance is late: 7-21 days
after infection appearance in noise and
serum at the same time.
 Antibody may clear virus from the body
finally.
Epidemiolohy and
Transmission
 Worldwide
 More often is in early autumn and late
spring and minimum in summer
 Transmission through fingers or shared
things is more important than aerosol
droplets.
 Family and school are two source of
contamination for children.
Treatment and prevention
 No spesific treatment
 No high chance for a vaccine production:
1. The culture for high concentration of virus
is difficult.
2. 2. The immunity is short.
3. 3. The serotypes are very high.
Adenoviruses
- Double-stranded linear DNA, icosahedral
nucleocapsid (80-90 nm).
- The only viruses with a fiber protruding
from each of the 12 vertices.
- The fiber is the organ of attachment and is a
hemagglutinin.
- There are more than 40 known antigenic
types and the fiber protein is the main typespecific antigen.
Diseases
 Upper respiratory tract infections:
Pharyngitis, pharyngoconjunctivitis.
 Conjunctivitis
 Pneumon
 Keratoconjunctivitis
 Hemorrhagic cystitis
 Gastroenteritis
 Latent infections particularly in the
adenoidal and tonsillar tissues.
Clinical findings of
adenovirus infection
 Varying degrees of fever, sore throat,
coryza, and conjunctivitis.
 In the lower respiratory tract, atypical
pneumonia is characterized primarily by
fever and cough.
Lab diagnosis
 Isolation of the virus in cell culture
 Detection of 4-fold rise in antibody titer.
 Serological tests: Hemagglutination test
Treatment and prevention
 Most adenovirus infections resolve
spontaneously.
 No antiviral therapy
 An enteric-coated capsule vaccine is used
only in military recruits in USA but not
available for civilian use.
The Influenza
&
Parainfluenza viruses
Orthomyxoviridae
&
Paramyxoviridae
Classification
Family:
ORTHOMYXOVIRIDAE
Genus:
Influenza virus
Types:
Type A
Type B
Type C
• “myxo” refers to interaction
with mucins (glycoproteins)
• Different from
paramyxoviruses : segmented genome
- smaller (average 110 nm in
diameter against 150 nm).
An enveloped viruse, helical symmetry
capsid, segmented linear RNA genome
Nucleocapsid:
Nucleoprotein (7 or 8 RNA segments)
Matrix protein (M)
Lipid bilayer
Haemaglutinin (HA)
Neuraminidase (NA)
80 to 120 nm
Surface
antigens
Internal
antigens
Surface glycoproteins
 Haemagglutinin
– H or HA
– responsible for pathogenicity of the virus
– allows virus to adhere to endothelial cells in the
respiratory tract
– main determinant of immunity
 Neuraminidase
– N or NA
– allows release of newly formed viruses within
host
– determinant of disease severity
Antibody against the hemagglutinin
neutralizes the infectivity of the
virus and prevents disease. Ab
against neuraminidase only reduces
disease.
Influenza subgroups
 Influenza A
– highly infective
– infects many species
– causes widespread epidemics
 Influenza B
– found only in humans
– capable of producing severe disease
– causes regional epidemics
 Influenza C
– causes mild disease
– humans are natural hosts, but isolates also found in pigs
– does not cause epidemics
Reassortment of segments of the
genome RNA
Influenza viruses, especially type A show
changes in the antigenicity of their
hemagglutinin and neuraminidase proteins. 
epidemics.
Influenza viruses antigenes
1.Group-specific (internal
ribonucleoprotein) antigenes.
2.Type-specific (surface N and H) antigens.
Many species of animal (eg. Birds, swine, and
hourses) have their own influenza A viruses.
These animal viruses are probably the source
of the new antigenic types.
Antigenic shift: Major changes based on
reassortment of genome pieces. Occurs every
10-11 years
Antigenic drift: Minor changes based on
mutation occurs every year.
Antigenic shift appears to result
from genetic recombination of
human with animal or bird
,providing
major
antigenic
change.This can cause a major
epidemic or pandemic involving
most or all age groups.
Epidemics and pandemics occur
when the antigenicity of the
virus has changed sufficiently
that the preexisting immunity of
many people is no longer
effective.
Various combinations of RNA segments can
result in a new subtype of virus (known as
antigenic shift
It is even possible to include RNA strands from
birds, swine, and human influenza viruses into
one virus if a cell becomes infected with all three
types of influenza.
Occurrence of influenza A
viruses
Influenza A viruses 16 HA types
9 NA types
Species affected
humans, pigs, horses,
birds, marine mammals
In humans
3 HA types (H1, H2, H3)
3 NA types (N1, N2, N8)
In birds
all HA types
all NA types
Influenza viruses nomenclature
For example:
A / Beijing / 32 / 92 (H3N2)
A
virus type, here A
Beijing
place where the strain was isolated
32
strain number
92
year of first isolation
H3N2
subtypes H3 and N2 virus sub type, here H3N2
ELECTRON MICROSOPE IMAGE
OF H1N1 INFLUENZA VIRUS
Pathogenesis
After the virus is inhaled, the
neuraminidase
degrades
the
protective mucus layer, allowing
the virus to gain access to the
cells of the upper and lower
respiratory tract.
Viremia rarely occurs, but there
is necrosis of the superficial
layers of respiratory epithelium.
Immunity
Circulating IgG against the virus occurs
after infection, but offers little protection.
Secretory IgA in the respiratory tract is
protective.
SYMPTOMS OF SWINE FLU IN
HUMANS
Clinical findings
• Incubation period: 24-48 hours
• Symptoms: fever, myalgias, headache,
cough develop suddenly.
• The symptoms resolve spontaneously in
4-7 days but sometimes is complicated
with secondary infections.
•Rey’s syndrome (Encephalopathy and
liver degeneration life-threatening
complication in children) following some
viral infections, particularly influenza B
and chikenpox, if they have been given
Asprin to reduce the fever.
COMPLICATIONS
Pneumonia
Respiratory failure
Convulsion (muscles contract and
relax rapidly and repeatedly, resulting in an
uncontrolled shaking of the body)
When to Seek Emergency
Medical Care
 has difficulty breathing or chest pain
 has purple or blue discoloration of the lips
 is vomiting and unable to keep liquids down
 has signs of dehydration such as dizziness when
standing, absence of urination, or in infants, a
lack of tears when they cry
 has seizures (for example, uncontrolled
convulsions)
 is less responsive than normal
RISK GROUPS
Persons with certain chronic medical
condition
School children
Travelers to some high risk places
Border workers
Health care workers or public health
workers
PREVENTION
 Prevention in swine or other
animal hosts.
 Prevention of transmission to
humans.
 Prevention of its spread among
humans.
Prevention of its spread among
humans.
Frequent
washing of
hands with
soap and
water
Use of
face
masks
Use of
towel while
sneezing
Use of
alcohol
based
sanitisers.
Lab diagnosis
1. Virus isolation (by throat washing)
with cell culture. Then flurescentantibody staining of the infected
cells by using antisera to influenza A
and B.
1. A rise in antibody titer of at least 4fold in serum samples using
hemmagglutination inhibition or
complement fixation.
1. PCR reactions
TREATMENT
supportive care is required.
 Antibiotics (to treat this disease, do help prevent
bacterial pneumonia and other secondary
infections.)
Viral agent is used in severe infections.
(Zanamivir is recommended by C.D.C.)
SWINE INFLUENZA
WHAT IS SWINE
INFLUENZA?
 Swine flu is a respiratory disease caused
by influenza viruses that infect the
respiratory tract of pigs.
 Swine flu produces most of the same
symptoms in pigs as human flu produces
in people.
HISTORY OF SWINE INFLUENZA
 The 1918 flu pandemic in
humans was associated with
H1N1 and influenza appearing in
pigs, this may reflect a zoonosis
either from swine to humans, or
from humans to swine.


Since the isolation of virus in 1933
major antigenic change have occurred
twice (1957-H2N2) and again in (1968H3N3)
Strains occuring between 1946 and
1957 have been called H1N1 strains.
VACCINE

The current trivalent influenza
vaccine is likely to provide
protection against the new 2009
H1N1 strain.
TREATMENT
 supportive

care is required.
Antibiotics (to treat this disease, do help
prevent bacterial pneumonia and other
secondary infections.)
 Zanamivir
C.D.C.
is recommended by
IN HUMANS
Bed Rest
 Keep the sick person in a room separate
from the common areas of the house.
 The U.S. Centers for Disease
Controland Prevention recommends the
use of Tamiflu (oseltamivir or Relenza
(zanamivir) for the treatment and/or
prevention of infection with swine
influenza viruses.
