Ph viruses eac for finals

VIRUSES OF
PUBLIC HEALTH
IMPORTANCE
March 2012

PUBLIC HEALTH
“protecting and improving health through education and promotion of
healthy lifestyles and research for disease and injury prevention”

Saturday, March 3, 2012

EMERGING INFECTIONS


EMERGING
INFECTIONS

FACTORS THAT LED
TO EMERGENCE
• Introduction of the agent into a new host
population, originating from:
• environment
• another host species
• variant of an existing human infection
• Establishment and further dissemination
within the new host population


FACTORS THAT LED
TO EMERGENCE
• Microbial adaptation
• Mutation
• Natural selection
• antibiotic-resistant bacteria
• Evolutionary progression
• Virulence factors

FACTORS THAT LED
TO EMERGENCE
• Human Susceptibility
• immune status
• nutrition
• age
• occupation, etc.
• Human behavior and demographics
• Affect disease dissemination

FACTORS THAT LED
TO EMERGENCE
• Changing ecosystems / land use

• Argentine, Bolivian hemorrhagic fever

• changes in agriculture (grassland to maize) favoring rodent host

• Hantaviruses

• Ecological or environmental changes increasing contact with
rodent hosts

• Rift Valley fever

• agriculture, irrigation


FACTORS THAT LED
TO EMERGENCE
• Economic development
• Dengue/DHF
• urbanization favoring mosquito vector
• Lassa fever
• urbanization favoring rodent hosts, increasing exposure
• Rift Valley fever
• dam building

FACTORS THAT LED
TO EMERGENCE
• Technology and industry
• Hepatitis B and C
• transfusions, organ transplants
• Inﬂuenza (pandemic)
• possibly pig-duck agriculture facilitating
reassortment


FACTORS THAT LED
TO EMERGENCE
• International travel and commerce
• Dengue/DHF
• Ebola, Marburg
• In Europe and US, importation of monkeys
• HIV
• Inﬂuenza (pandemic)
• SARS

INFLUENZA


THE BASICS...
• Inﬂuenza is an acute, viral respiratory infection

• When to suspect?

• Fever, chills, headache, aches and pains throughout
the body, sore throat which may lead to
bronchitis or pneumonia

• Vomiting and diarrhea may also occur

• Many deaths have been attributed to inﬂuenza


3 TYPES


PANDEMICS
• PANDEMIC: world wide spread of infection
occurring in many countries simultaneously
• INFLUENZA PANDEMICS: occur approximately
every thirty years
• REASON FOR OCCURRENCE: new strain of
the virus emerges for which people have no
immunity and there are no vaccines available


THE ABILITY OF INFLUENZA
TO CAUSE PANDEMICS
HA - hemagglutinin

NA - neuraminidase

helical nucleocapsid (RNA plus
NP protein)

lipid bilayer membrane

polymerase complex

M1 protein


THE ABILITY OF INFLUENZA TO
CAUSE PANDEMICS
• Haemagglutinin (H)

• attaches the virus to
cells and allows the
viral envelope to fuse
with the cell membrane
and enter cells

• Neuraminidase (N)

• allow the release of
viruses to infect other
cells


ANTIGENIC DRIFT &
ANTIGENIC SHIFT


LIFE CYCLE & TRANSMISSION

• The virus is spread by
inhalation or by direct
contact
• Reservoirs of infection:
primarily humans, but birds
and pigs can act as reservoirs
• Multiple host status = mixing
of ﬂu types


CONTROL &
PREVENTION

• EDUCATION
• ISOLATION
• VACCINATION
• PROPER
HYGIENE


VACCINE (H) & CHEMOTHERAPY (N)


VACCINE (H) &
CHEMOTHERAPY (N)


DENGUE


THE VECTOR:
Aedes aegypti/albopictus


INSIDE THE
MOSQUITO & INSIDE
YOU...


TRANSMISSION


PATHOGENESIS
1.The virus is inoculated into
humans with the mosquito saliva.

2.The virus localizes and replicates
in various target organs, for
example, local lymph nodes and the
liver.

3.The virus is then released from
these tissues and spreads through
the blood to infect white blood
cells and other lymphatic tissues.

4.The virus is then released from
these tissues and circulates in the
blood.


PATHOGENESIS
5.The mosquito ingests blood
containing the virus.

6.The vir us replicates in the
mosquito midgut, the ovaries,
nerve tissue and fat body. It then
escapes into the body cavity, and
later infects the salivary glands.

7.The vir us replicates in the
salivar y glands and when the
mosquito bites another human,
the cycle continues.


WHY
DENGUE
HAS
EMERGED


PREVENTION & CONTROL


THE VIRUS


LIFE
CYCLE


DRUGS FOR HIV ARE
BASED ON ITS LIFE
CYCLE


HOW YOU CAN
GET IT..


DISEASE COURSE


HEPATITIS


HEPATITIS B

HEPATITIS C


SARS


THE OUTBREAK
• In November 2002, highly contagious and severe
atypical pneumonia were observed in the
Guangdong Province of southern China
• The virus was spread to Hong Kong in February
2003 by a doctor who died 10 days after
admission into local hospital = a mysterious
death
• Similar outbreaks occurred at different local
communities subsequently


THE HOT ZONES


SEVERE ACUTE
RESPIRATORY SYNDROME
(SARS)

• Cause : SARS CoV

• Highly infectious

• Mainly affects adults

• Superspreading events important in transmission
process

• No reports of transmission occurring before onset
of symptoms


NATURAL
RESERVOIRS


TRANSMISSION
• Evidence of person to person
transmission
• Close contact with body ﬂuids
(especially respiratory droplets )
• Contaminated hands, clothes,
equipment; environment may also be
important


Ph viruses eac for finals

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Ph viruses eac for finals

Similar to Ph viruses eac for finals (20)

More from Marilen Parungao

More from Marilen Parungao (20)

Recently uploaded

Recently uploaded (20)

Ph viruses eac for finals