c. Rickettsiae. Rickettsial diseases include:
Rocky mountain spotted fever
d. Protozoa. The classical example of a protozoan disease transmitted by
arthropods is malaria, which is caused by several species of the genus Plasmodia,
harbored in the body of various mosquitoes.
e. Nematodes. The filarial diseases are caused by microscopic nematodes
(roundworm s) known as filariae, which are transmitted by the bite of a mosquito or fly.
MECHANISMS OF DISEASE TRANSMISSION
Arthropods are capable of transmitting disease agents by two methods:
a. Passive/Mechanical Transmission. In passive/mechanical transmission,
the arthropod come into contact with infectious agents, which adhere to the body or
hairs of the bug as he travels from manure pile to outdoor latrine, garbage cans, or
other source of filth. Gaining access to food or eating utensils, the arthropod then
deposits the organisms where they will be eaten by humans or animals.
b. Active/Biological Transmission. In active/biological transmission, the
pathogenic organism actually undergoes a portion of its life cycle in the body of the
arthropod. There are four mechanisms, by which an arthropod can actively, or
biologically transmit a disease.
(1) Inoculation. Certain bloodsucking arthropods, such as the mosquito,
insert a proboscis into the victim in order to withdraw the blood meal. In so doing, the
insect also injects disease organisms along with its saliva into the victim's bloodstream.