EPIDEMIOLOGY IN MEDICAL ENTOMOLOGY

epidemiology

study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

Study (scientific inquiry)
Distribution (frequency and pattern of health events)
Determinants (contributing factors to health states)
Specified populations (affected groups)
Application (using epidemiology for health control)

What are the five key components of epidemiology

entomological epidemiology

A field that identifies the mechanism of transmission of arthropod-borne diseases and diseases associated with arthropod bites.

Scabies

Give an example of an arthropod-borne disease that is not caused by blood parasites.

Zika
Malaria
Elephantiasis
Dengue
Yellow Fever

List five mosquito-borne diseases

vector

A living organism that can transmit pathogens between humans or from animals to humans.

Mosquitoes
Ticks
Fleas

Name three types of vectors

Host
Pathogen
Vector

What are the three key components of the epidemiologic triad in vector-borne disease dynamics?

Horizontal transmission
Vertical transmission

What are the two main modes of transmission in vector-borne diseases?

Horizontal transmission

Passage of parasites from vectors to vertebrate hosts, or between vectors

Mechanical, Biological

Horizontal transmission types

Mechanical transmission

carrier; no biological processes inside the vector

Biological transmission

with biological processes

Vertical transmission

Passage of parasites directly to subsequent life stages or generations (mother passing the agent to the offspring)

• Transstadial

• Transgenerational

Vertical transmission types

Transstadial transmission

passage of a pathogen from one life stage of an arthropod vector to the next, without losing the infection.

Transgenerational transmission

passage of a pathogen from a parent vector to its offspring.

Demonstration of feeding under natural conditions
Demonstration of overlaps between vector density and disease prevalence
Evidence that the vector harbors the pathogen in the infective stage
Laboratory demonstration of vector infection

What are the four criteria for incriminating an arthropod as a vector?

Gut morphology
Peritrophic membrane
Proventricular spines
Cibarial armature

What anatomical characteristics affect a vector’s ability to transmit pathogens?

Gut morphology

some vectors can harbor pathogens better than others

Peritrophic membrane

acts as a barrier against pathogen invasion

Proventricular spines

in fleas, aid in Yersinia pestis transmission

Cibarial armature

teeth-like structures in mosquitoes affecting parasite survival

Enzymes in vectors

can either support or hinder the development of pathogens

Host preference
Feeding patterns
Resting behavior

What behavioral differences impact a vector’s ability to transmit disease?

vector surveillance

involves studying species, numbers, and effectiveness of control programs to prevent and monitor vector-borne disease outbreaks.

Light traps
Ovitraps
Flagging

Name three collection methods used to estimate vector populations.

4 o’clock habit

A coordinated community effort where people eliminate potential mosquito breeding sites daily at 4:00 PM.

Search and destroy mosquito breeding sites
Self-protection measures
Say no to indiscriminate fogging
Seek early consultation

What are the 4S strategies in dengue control?

Wolbachia bacteria

interfere with the mosquito’s ability to transmit dengue, Zika, and other viruses, reducing disease transmission.

Extrinsic incubation

period required for a pathogen to develop inside the vector before it becomes infectious, influencing disease transmission rates.