unit 3.1.3: communicable diseases (cont.)

Influenza

Influenza

an enveloped virus and an RNA virus

spherical

Influenza:

Etiology

Shape of the Capsid

antigenic glycoprotein, neuraminidase, and hemagglutinin

Influenza:

Etiology

Genetic makeup of the Capsid

A

Influenza:

Etiology

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)

Influenza:

Etiology

Subtype A

Classified into subtypes based on combinations of ___

A(H1N1) and A(H3N2)

Influenza:

Etiology

Subtype A

Currently circulating in humans

Type

Influenza:

Etiology

Subtype A

A/Beijing/262/95

Site of isolation

Influenza:

Etiology

Subtype A

A/Beijing/262/95

Culture number

Influenza:

Etiology

Subtype A

A/Beijing/262/95

Year

Influenza:

Etiology

Subtype A

A/Beijing/262/95

B: B/Yamagata and B/Victoria

Influenza:

Etiology

broken down into lineages

C

Influenza:

Etiology

Most stable, Low pathogenicity (subclinical infection)

Antigenic Drift

Influenza:

Etiology

mutation in the genes of the Influenza virus and would lead to changes in the surface antigens

Antigenic Shift

Influenza:

Etiology

• 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

Influenza:

Symptoms

Uncomplicated illness

Pneumonia sequelae

Influenza:

Symptoms

main cause of mortality especially in high risk individuals

• Respiratory droplets

• Direct contact

• Highly infectious

Influenza:

Epidemiology

Transmission

1 to 5 days

Influenza:

Epidemiology

Incubation Period

2 days before onset of symptoms to 5 days after

Influenza:

Epidemiology

Period of Communicability

A(H1N1) Swine Flu (2010)

Influenza:

Epidemiology

Occurrence & Distribution

• originated in Mexico in 2009

1918 Spanish Flu: Influenza A

Influenza:

Epidemiology

Occurrence & Distribution

• responsible for pandemics and regular seasonal outbreaks

rainy seasons

Influenza:

Epidemiology

Occurrence & Distribution

• In Tropics

winter months

Influenza:

Epidemiology

Occurrence & Distribution

• In Temperate Climates

PCR (RT-PCR)

Influenza:

Diagnosis

method of choice

Antiviral Agents

Influenza:

Treatment

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

Influenza:

Prevention & Control

most effective way to prevent disease

WHO Global Influenza Surveillance and Response System (GISRS)

Influenza:

Prevention & Control

continuously monitors influenza viruses in humans and updates composition of influenza vaccines twice a year

Personal Protective Measures

Influenza:

Prevention & Control

• 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

COVID-19

2003

MERS-CoV

COVID-19

2012

SARS-CoV-2

COVID-19

2019

solar corona

COVID-19:

Etiology

widely-spaced projections or spikes on the outer surface of the envelope

Severe Acute Respiratory Syndrome

COVID-19:

Etiology

SARS-CoV (2003)

Middle East Respiratory Syndrome

COVID-19:

Etiology

MERS-CoV (2012)

Coronavirus Disease 2019: Severe Acute Respiratory

Syndrome Coronavirus 2

COVID-19:

Etiology

COVID-19 Virus

bats: amplified in palm civets

COVID-19:

Etiology: Origin

SARS-CoV (2003)

bats: widespread in camels

COVID-19:

Etiology: Origin

MERS-CoV (2012)

bat to a pangolin

COVID-19:

Etiology: Origin

COVID-19 Virus

• Respiratory symptoms

• Fever

• Malaise

• Chills

• Headache

• Dry cough

COVID-19:

Symptoms

Early Symptoms

acute respiratory distress, requiring ventilatory support

COVID-19:

Symptoms

abnormal chest radiographs

• Pneumonia

• Severe Acute Respiratory Syndrome

• Kidney Failure

• Death

COVID-19:

Symptoms

Severe Cases

Coronavirus-associated Enteritis

COVID-19:

Symptoms

have not been clearly described

Basic Reproduction Number of Diseases

COVID-19:

Epidemiology

basic measure to track the infectiousness of the disease

PCR (RT-PCR): preferred

COVID-19:

Diagnosis

Nucleic Acid Detection

Serodiagnosis

COVID-19:

Diagnosis

Serology

• acute and convalescent sera is one means of confirming

serum

COVID-19:

Diagnosis

Serology

• ELISA specimen

Shepherd’s crook morphology

Ebola:

Etiology

”U” or “6” shape

Reston virus

Ebola:

Etiology

cause disease in primates

Filovirus

Ebola:

Etiology

highly virulent and require maximum containment facilities for laboratory work

bats (fruit bats)

Ebola:

Etiology

Natural/Reservoir Hosts

Filovirus

Ebola:

Symptoms

appear to be immunosuppressive

• Direct contact

• Contaminated needle and syringes

• saliva and through large droplets

Ebola:

Epidemiology

Transmission

viral hemorrhagic fevers is 25-90%

Ebola:

Epidemiology

Mortality Rate

50%

Ebola:

Epidemiology

Fatality Rate

2013-2016 West African Outbreak

Ebola:

Epidemiology

Outbreaks

• Major ebola outbreak in Guinea

WHO declared the epidemic an international public health emergency

Ebola:

Epidemiology

Outbreaks

• 8 Aug 2014

Sudan Outbreak

Ebola:

Epidemiology

Outbreaks

• first known outbreak of EVD

Zaire Outbreak

Ebola:

Epidemiology

Outbreaks

• second outbreak (Democratic Republic of the Congo)

village’s headmaster

Ebola:

Epidemiology

Outbreaks

• First person with the disease

White blood & Oral fluid

Ebola:

Diagnosis

Specimen

• Low white cell count

• Platelet count

• Elevated liver enzymes

Ebola:

Diagnosis

Laboratory Findings

Experimental Ebola Vaccine: rVSV-ZEBOV

Ebola:

Treatment

Not yet out in the market because it is still in the experimental process

Mosquitos of Aedes group

Dengue:

Vector

• Aedes aegypti

• Aedes albopictus

Dengue:

Vector

Species responsible for transmission and spread of Zika, Chikungunya

Aedes albopictus

Dengue:

Vector

• it can withstand cold temperatures

• black color and with distinctive white markings

stagnant water, old tires, empty tins or others that can collect water

Dengue:

Vector

breeding grounds for mosquitoes

• Sudden-onset fever

• Headache

• Mouth and nose bleeding

• Muscle and joint pains

• Vomiting

• Rash

• Diarrhea

Dengue:

Symptoms

Febrile Phase

• Hypotension

• Pleural effusion

• Ascites

• Gastrointestinal bleeding

Dengue:

Symptoms

Critical Phase

• Altered level of consciousness

• Seizures

• Itching

• Slow heart rate

Dengue:

Symptoms

Recovery Phase

Herman’s Rash

Dengue:

Symptoms

• 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

Dengue:

Symptoms

Mostly mild and people can recover without severe hospitalization

• Guillain-Barre syndrome

• Microcephaly

Chikunguya

Dengue:

Symptoms

Severe joint pains

increased 30-fold over the last 50 years

Dengue:

Epidemiology

Incidence

~50 to 100 million infections

Dengue:

Epidemiology

annually in >100 endemic countries

3.9 billion

Dengue:

Epidemiology

at risk of infection with Dengue viruses

ubiquitous

Dengue:

Epidemiology

appearing or found everywhere

“Asian” Genotypes of DENV-2 and DENV-3

Dengue:

Epidemiology

associated with severe disease accompanying secondary Dengue infections

Severe Dengue

Dengue:

Epidemiology

first recognized in the Philippines and Thailand in the 1950s during Dengue epidemics

rainy season (May-Nov)

Dengue:

Epidemiology

Philippines

Peak Transmission

0.55%

Dengue:

Epidemiology

Philippines

Case Fatality Rate

Climate

Dengue:

Epidemiology

one important driver of the current distribution and incidence of Dengue

Temperature

Dengue:

Epidemiology

most important predictor of distribution

high fever (40°C or 104°F) and two accompanying symptoms

Dengue:

Symptoms

Positive tourniquet test & Low white cell count

Dengue:

Diagnosis

PCR (RT-PCR)

Dengue:

Diagnosis

Nucleic Acid Detection

NS1 (nonstructural protein 1)

Dengue:

Diagnosis

Viral Antigen Detection

ELISA

Dengue:

Diagnosis

Antibody Testing (Serological test)

Breeding of fish: Guppies

Dengue:

Vector Control

Biologic Control

• eliminate mosquitoes from larger containers used to store potable water

Indoor Residual Spraying

Dengue:

Vector Control

Chemical Control

• Application of long-acting chemical insecticides on the walls and roofs

• short period of time

Space Sprays

Dengue:

Vector Control

Chemical Control

• Massive, rapid destruction of adult vector population

• emergency situations to suppress an ongoing epidemic

• aircraft, vehicle, hand-held equipment

Environmental Modification

Dengue:

Vector Control

Environmental Management

• Improvement of water supply and water-storage systems

Environmental Manipulation

Dengue:

Vector Control

Environmental Management

• Mosquito-proofing

Changes to Human Habitation or Behavior

Dengue:

Vector Control

Environmental Management

• Mosquito screening & repellants

“Kung Walang Lamok, Walang Dengue”

Dengue:

Vector Control

Mag 4S Kontra Dengue by the DOH

June 15, 2018

Dengue:

Vector Control

Asean Dengue Day

Dengvaxia® (CYD-TDV)

Immunization

Developed by Sanofi Pasteur

seropositive individuals

Dengvaxia®:

persons who have had a previous dengue virus infection -- efficacious and safe

seronegative individuals

Dengvaxia®:

first natural dengue infection after vaccination -- increased risk of severe dengue

Wolbachia

Dengue:

• 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