Main Topics in Entomology: Insects as Disease Vectors
A great deal of human and animal diseases is due to pathogens transmitted by insects. Among the deadliest infectious diseases worldwide, malaria and dengue hemorrhagic fever are vector-borne diseases. Many insect vectors belong to the Diptera Order, such as mosquitoes, biting midges, sandflies, blackflies, and tsetse-flies, but insects of other orders can also transmit important pathogens like the lice, fleas, and bloodsucking bugs. Pathogenic agents could be parasites (protozoan, filariae, cestods, etc), bacteria (rickettsiae, borellia, etc), viruses (arboviruses) that undergo a cycle of development inside the insect vector to reach their infective stage. Transmission can be done through the insect's bite with direct inoculation or with pathogens deposited by the insect saliva or faeces on the skin, and entering into their host either through scratching or by active action of the pathogen into the host wound.
For these insect-borne diseases, vector control is one of the first preventive measures, if not the only one in most cases due to the lack of vaccine (except for yellow fever and Japanese encephalitis) and resistance issues in chemoprophylaxis. Therefore, vector control is an integral component of vector-borne disease control programmes. However, in order to reach their full efficiency, vector control operations and programmes must be based on sound knowledge of the targeted vectors (species identification, biology, distribution,