b. Respiratory Diseases. Respiratory diseases are those acquired primarily
through inhalation of causative agents. While some respiratory diseases affect the
respiratory system, others are manifested principally in other body areas. The common
cold, influenza, and smallpox are examples of respiratory diseases.
c. Arthropod-Borne Diseases. Arthropod-borne diseases are transmitted by
arthropods, including insects such as mosquitoes, lice, fleas, and flies; and by
arachnids, including ticks and mites. Most disease-bearing arthropods (disease
vectors) are bloodsuckers. Malaria, yellow fever, typhus fever, and plague are classical
examples of arthropod-borne diseases.
d. Miscellaneous Diseases Miscellaneous diseases include those that do not
fit into one of the groups named in (a) through (c) above and also include those for that
the transmitting agent is unknown.
Figure 1-3. One method of classifying communicable diseases