unit 3.1.3: communicable diseases (cont.)

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 situation**s 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