Communicable diseases have been cited to cause several deaths as well as suffering to a huge populace in the underdeveloped world. These diseases may be spread through contact, ingestion of contaminated food or water, inhalation of contaminated air as well as through vectors. Vectors spread the communicable diseases through biological as well as mechanical means. In the latter case the vector picks up the infectious agent from a contaminated source and carries it outside its body to another media such as food or water where the agent is deposited. Consumption of such food therefore results in an infection. Flies are good example of mechanical vectors as they passively transmit infectious agent causing cholera to humans through the aforementioned media. On the other hand, vectors may also spread the diseases trough biological means where pathogens are harbored in the body of the vectors and transmitted in an active manner to the potential host. This may be exemplified by the spread of rabies from rabid animals to man through bites. Some communicable diseases may be spread through a variety of means such as cholera which can be transmitted through flies, feces, water as well as food. Such diseases require a multiple approach of control encompassing a continuum of food, water, air, personal hygiene, insects as well as sewage disposal (Munson, 2009).
It is always important to define the means of transmission of an infectious agent in an attempt to fully understand the biology of a disease so as to control the disease. Communicable diseases are spread through a variety of media including water, food, air, insects as well as contaminated objects. To begin with humans have contributed highly to such spread by providing a suitable environment for the growth and spread of the infectious agent. For instance, the generation and poor disposal of human wastes such as feces in the public have provided food source to vectors such as flies which thereafter transport the infectious agents from the wastes to the media such as food and water in human residence prior to consumption. The subsequent consumption of such infected food or water may cause diseases such as cholera, dysentery as well as typhoid. Ingestion of fecally contaminated water may enhance the spread of Giardiasis. On the other hand, food provides a suitable growth media for the vectors when poorly kept. High degree of hygiene is necessary in preventing the spread of diseases such as salmonellosis whose causative agent thrives well in a poorly preserved food and may be ingested upon consumption (Munson, 2009).
Vector-borne diseases may also be spread through formites. These are contaminated objects that provide a suitable resting place for vectors. For instance, objects such as paper or money may harbor infectious agents that can easily be transferred by vectors from one person to the other when such objects are shared among individuals. The spread of diseases such as TB is necessitated by formites especially when individuals put such contaminated objects in their mouths. Communicable diseases may also be spread by vectors through biological means. The transmission of diseases such as rabies and the bacillus of bovine TB from animals to humans follow the aforementioned transmission mode. For instance, rabies is transmitted to humans when bitten by a rabid animal. This is an active transmission and may therefore be lethal especially when such bites are executed in delicate such places as head, face or even neck (Acha et al, 2003). Typhus fever is also transmitted by body louse which has fed on the blood of a patient suffering from the fever and transferred rickettsia from their excreta to the new host. This can be avoided by enhancing body hygiene and general sanitation to keep away the louse.
Communicable diseases cause high rate of mortality and morbidity especially in the third world countries where comprehensive control measures are not well established. The diseases may at times be spread through a variety of media including water, food, air, formites as well as insects. It is therefore important to establish environmental control strategies that entail multiple facets encompassing continuum of food, water, air, personal hygiene, insects as well as sewage disposal. Personal hygiene as well as general sanitation is fundamental to the control of communicable diseases. According to Acha et al (2003) control of vector-borne diseases should be directed to the vector itself followed by the rodents.
Acha, P.et al (2003). Zoonoses and Communicable Diseases Common to Man and Animals:
Chlamydioses, rickettsioses, and viroses. 3rd Ed. New York: American Health Org
Munson, F. (2009). Hygiene of Communicable Diseases; A Handbook for Sanitarians, Medical
Officers of the Army and Navy and General Practitioners. New York: General Books LLC.