Studied by 5 people
Influenza
an enveloped virus and an RNA virus
spherical
Shape of the Capsid
antigenic glycoprotein, neuraminidase, and hemagglutinin
Genetic makeup of the Capsid
A
Least stable with antigenic drift and antigenic shift of the H and N antigens producing new strains responsible for epidemics
Hemagglutinin (HA) and Neuraminidase (NA)
Classified into subtypes based on combinations of ___
A(H1N1) and A(H3N2)
Currently circulating in humans
Type
A/Beijing/262/95
Site of isolation
A/Beijing/262/95
Culture number
A/Beijing/262/95
Year
A/Beijing/262/95
B: B/Yamagata and B/Victoria
broken down into lineages
C
Most stable, Low pathogenicity (subclinical infection)
Antigenic Drift
mutation in the genes of the Influenza virus and would lead to changes in the surface antigens
Antigenic Shift
from the strains of two or more different viruses and they combine to form another subtype
newly formed subtype will have a mixture of different surface antigens or the antigenic glycoproteins
lasts about 5 days
Uncomplicated illness
Pneumonia sequelae
main cause of mortality especially in high risk individuals
Respiratory droplets
Direct contact
Highly infectious
Transmission
1 to 5 days
Incubation Period
2 days before onset of symptoms to 5 days after
Period of Communicability
A(H1N1) Swine Flu (2010)
Occurrence & Distribution
originated in Mexico in 2009
1918 Spanish Flu: Influenza A
Occurrence & Distribution
responsible for pandemics and regular seasonal outbreaks
rainy seasons
Occurrence & Distribution
In Tropics
winter months
Occurrence & Distribution
In Temperate Climates
PCR (RT-PCR)
method of choice
Antiviral Agents
formulated through the use of the causative agent of the virus; the genetic makeup of the virus will be fragmented and part of the virus will be tested to create an agent to combat the virus
Vaccination
most effective way to prevent disease
WHO Global Influenza Surveillance and Response System (GISRS)
continuously monitors influenza viruses in humans and updates composition of influenza vaccines twice a year
Personal Protective Measures
Regular hand washing
Good respiratory hygiene
Early self-isolation
Avoiding close contact
Avoiding touching one’s eyes, nose, or mouth
Coronavirus (COVID-19)
causes respiratory infections and it spreads from one person to the other through droplets
SARS-CoV
2003
MERS-CoV
2012
SARS-CoV-2
2019
solar corona
widely-spaced projections or spikes on the outer surface of the envelope
Severe Acute Respiratory Syndrome
SARS-CoV (2003)
Middle East Respiratory Syndrome
MERS-CoV (2012)
Coronavirus Disease 2019: Severe Acute Respiratory
Syndrome Coronavirus 2
COVID-19 Virus
bats: amplified in palm civets
SARS-CoV (2003)
bats: widespread in camels
MERS-CoV (2012)
bat to a pangolin
COVID-19 Virus
Respiratory symptoms
Fever
Malaise
Chills
Headache
Dry cough
Early Symptoms
acute respiratory distress, requiring ventilatory support
abnormal chest radiographs
Pneumonia
Severe Acute Respiratory Syndrome
Kidney Failure
Death
Severe Cases
Coronavirus-associated Enteritis
have not been clearly described
Basic Reproduction Number of Diseases
basic measure to track the infectiousness of the disease
PCR (RT-PCR): preferred
Nucleic Acid Detection
Serodiagnosis
Serology
acute and convalescent sera is one means of confirming
serum
Serology
ELISA specimen
Shepherd’s crook morphology
”U” or “6” shape
Reston virus
cause disease in primates
Filovirus
highly virulent and require maximum containment facilities for laboratory work
bats (fruit bats)
Natural/Reservoir Hosts
Filovirus
appear to be immunosuppressive
Direct contact
Contaminated needle and syringes
saliva and through large droplets
Transmission
viral hemorrhagic fevers is 25-90%
Mortality Rate
50%
Fatality Rate
2013-2016 West African Outbreak
Outbreaks
Major ebola outbreak in Guinea
WHO declared the epidemic an international public health emergency
Outbreaks
8 Aug 2014
Sudan Outbreak
Outbreaks
first known outbreak of EVD
Zaire Outbreak
Outbreaks
second outbreak (Democratic Republic of the Congo)
village’s headmaster
Outbreaks
First person with the disease
White blood & Oral fluid
Specimen
Low white cell count
Platelet count
Elevated liver enzymes
Laboratory Findings
Experimental Ebola Vaccine: rVSV-ZEBOV
Not yet out in the market because it is still in the experimental process
Mosquitos of Aedes group
Vector
Aedes aegypti
Aedes albopictus
Species responsible for transmission and spread of Zika, Chikungunya
Aedes albopictus
it can withstand cold temperatures
black color and with distinctive white markings
stagnant water, old tires, empty tins or others that can collect water
breeding grounds for mosquitoes
Sudden-onset fever
Headache
Mouth and nose bleeding
Muscle and joint pains
Vomiting
Rash
Diarrhea
Febrile Phase
Hypotension
Pleural effusion
Ascites
Gastrointestinal bleeding
Critical Phase
Altered level of consciousness
Seizures
Itching
Slow heart rate
Recovery Phase
Herman’s Rash
acute stage of the infection
blanches when the back is pressed with the finger
“Classic island of white in a sea of red”
small red spots on the skin
starts on the arms and legs and spreads to the rest of the body
Zika
Mostly mild and people can recover without severe hospitalization
Guillain-Barre syndrome
Microcephaly
Chikunguya
Severe joint pains
increased 30-fold over the last 50 years
Incidence
~50 to 100 million infections
annually in >100 endemic countries
3.9 billion
at risk of infection with Dengue viruses
ubiquitous
appearing or found everywhere
“Asian” Genotypes of DENV-2 and DENV-3
associated with severe disease accompanying secondary Dengue infections
Severe Dengue
first recognized in the Philippines and Thailand in the 1950s during Dengue epidemics
rainy season (May-Nov)
Peak Transmission
0.55%
Case Fatality Rate
Climate
one important driver of the current distribution and incidence of Dengue
Temperature
most important predictor of distribution
high fever (40°C or 104°F) and two accompanying symptoms
Symptoms
Positive tourniquet test & Low white cell count
PCR (RT-PCR)
Nucleic Acid Detection
NS1 (nonstructural protein 1)
Viral Antigen Detection
ELISA
Antibody Testing (Serological test)
Breeding of fish: Guppies
Biologic Control
eliminate mosquitoes from larger containers used to store potable water
Indoor Residual Spraying
Chemical Control
Application of long-acting chemical insecticides on the walls and roofs
short period of time
Space Sprays
Chemical Control
Massive, rapid destruction of adult vector population
emergency situations to suppress an ongoing epidemic
aircraft, vehicle, hand-held equipment
Environmental Modification
Environmental Management
Improvement of water supply and water-storage systems
Environmental Manipulation
Environmental Management
Mosquito-proofing
Changes to Human Habitation or Behavior
Environmental Management
Mosquito screening & repellants
“Kung Walang Lamok, Walang Dengue”
Mag 4S Kontra Dengue by the DOH
June 15, 2018
Asean Dengue Day
Dengvaxia® (CYD-TDV)
Developed by Sanofi Pasteur
seropositive individuals
persons who have had a previous dengue virus infection -- efficacious and safe
seronegative individuals
first natural dengue infection after vaccination -- increased risk of severe dengue
Wolbachia
A natural bacteria present in up to 60% of insects, including some of the mosquitoes, (the primary species responsible for transmitting the virus to humans) but not usually found in aedes mosquitoes
Self-perpetuating intracellular bacteria with disease blocking action
mosquito resistant to dengue virus
Note
Flashcard