Arthropods of medical importance are recognized by many as vectors - transmitters of viruses, bacteria, protozoa, and helminths. Transmission to humans may be:
- Biological: Where infectious agents have an obligate relationship with the arthropod (as in malaria - the parasites need the arthropod to develop and survive)
or
- Mechanical: Where infectious agents contaminate the arthropod (and thus transmit to the human when the arthropod lands on or crawls on the human)
Five major groups of vectors exist:
- Diptera (flies and mosquitoes)
- Hemiptera (bedbugs, kissing bugs)
- Siphonaptera (fleas)
- Anoplura (lice)
- Acarines (ticks and mites)
(It is beyond this course's scope to discuss the arthropod life cycles in detail, except where certain scenarios might prove useful to the identification.)
