Entomology -An Introduction

Entomology is the branch of zoology which deals with the study of insects.

Medical Entomology concerned with those arthropods which transmit diseases from one host  to another host. For example anopheles mosquitoes, sand flies, ticks and mites.

What is Vector?

Vectors are those living agents which transmit or help to transmit disease from infected person to a healthy person i.e. anopheles mosquito transmits malaria and house fly transmits pathogens/ bacteria from one place to another place.

Anopheles stephensi is urban speice while Anopheles culicifacae is rural specie.

Vectors are of two types: Mechanical and biological.

What is Metamorphosis?

This is a process of development in insects from an egg stage to adult form. So the collective changes that occur from an egg stage to adult form is called Metamorphosis.

Types of Metamorphosis

There are two types of metamorphosis.

Complete Metamorphosis

In this type of metamorphosis there are four developmental stages and the newly emerging larva are completely different from the adult one. For example mosquito and sand fly.

Egg——     Larva—— Pupa—— Adult

Incomplete Metamorphosis

In this type of Metamorphosis there are three developmental stages and the newly emerged Nymph is just like the adult one in its morphology and habit, but smaller in size, for example lice and bedbug.

Egg—— Nymph—— Adult

Arthropods of Medical Importance

1.      Mosquito
2.      House fly
3.      Flea
4.      Sand fly
5.      Tsetse fly
6.      Lice
7.      Bed bug
8.      Tick
9.      Mites
10.  Cyclops

Transmission of Arthropods-born diseases

1. By direct contact: –    

The arthropods are transferred by direct contact for i.e. scabies and pediculosis.

2. By mechanical transmission: –

The disease agents are transferred mechanically by arthropods i.e. diarrhea, typhoid & paratyphoid.

3. By biological transmission: –

When the disease agents multiply in the body of vector i.e. malaria.