Navy and Marine Corps personnel are exposed to a wide variety of environmental conditions, including climatic extremes, stressful situations, and close living quarters. Many of these personnel travel to foreign lands where conditions may not only be unsanitary, but where a high level of disease may also exist. Preventive medicine's major role is to minimize disability by emphasizing immunization programs.

Immunizations
Vaccines used to protect Navy and Marine Corps personnel against certain diseases before exposure to infection are called prophylactic immunizations. Prophylactic immunizations are limited to very serious diseases for which effective and reliable immunizing agents have been developed.

Immunizations procured for the Armed Forces are required to meet the minimum standards set by the Department of Health and Human Services (DHHS).

Immunizations for Military Personnel
Navy and Marine Corps personnel are required to be ready to deploy on a moment's notice. To make sure personnel are prepared for deployment, you should review their immunization records on a routine basis, and, before deployments, also review BUMEDINST 6230.15, Immunizations and Chemoprophylaxis. Initial and booster dosages and routes of administra- tion are dictated by the vaccine manufacture, the U.S. Public Health Service Immunization Practices Advisory Committee (ACIP), or both.

Communicable Diseases
Communicable diseases, as the name implies, are diseases that may be transmitted from a carrier to a susceptible host. They may be transmitted from an infected person or animal or indirectly through an intermediate host, vector, or inanimate object. The illness produced is the result of infectious agents invading and multiplying in the host, or from the release of their toxins (poisons).

An important step in the control of communicable disease is the expedious preparation and submission of the Medical Event Report. Instructions and requirements for reporting to local, state, national, and international health authorities can be found in the preface of the Control of Communicable Diseases Manual, NAVMED P-5038. In addition, you should follow instructions for the Medical Event Report (MER), BUMEDINST 6220.12, when reporting communicable diseases affecting Navy and Marine Corps personnel.

WATER SUPPLY
A hygienically safe and continuously dependable water supply is a necessity of life. Drinking water should be free of disease-producing organisms, poisonous chemicals, as well as from objectionable color, odor, and taste. For more detailed instruction on these topics, you should review the Manual of Naval Preventive Medicine, NAVMED P-5010.

Water Supply Ashore
With rare exceptions, Navy and Marine Corps activities ashore within the continental limits of the United States are situated where a municipal water supply is available. BUMEDINST 6240.1, Standards for Potable Water, sets drinking water standards for U.S. naval establishments worldwide, both ashore and afloat.

Water Supply in the Field
Hospital Corpsmen are frequently called upon to approve field water sources and to recommend disinfection methods before water is considered safe to drink. Consider water acquired in the field as unsafe until it has been disinfected and tested. Approval of water sources should be based on a thorough surveillance of available water sources.

WATER QUANTITY REQUIREMENTS.- The daily water requirements for personnel in the field vary with a number of factors, including the season of the year, geographical location, and the tactical situation. Personnel who do not drink enough water can quickly become dehydrated both in extremely hot or extremely cold climates.

WATERTREATMENT.-Water treatment is the process of purifying water to make it potable (safe to drink). Various processes can be used to purify water. These processes include aeration, coagulation, flocculation, filtration, reverse osmosis, and disinfection, all of which are discussed in depth in NAVMED P-5010.

Water Supply Afloat
Potable water for shipboard use comes from one of several sources: the ship's distillation plant, shore-to-ship delivery, or ship-to-ship transfer. The ship's medical department is responsible for determining the quality of the water. The ships engineering section determines the quantity stored or produced, and performs the actual chlorination or bromination.

Water Testing
Naval vessels follow water testing requirements and procedures outlined in the latest edition of Standard Methods for the Examination of Water and Wastewater, published by the American Public Health Association (APHA), American Water Works Association (AWWA), and the Water Pollution Control Federation (WPCF).

Manufacture and Handling of Ice
Most ships and shore activities use ice machines to make ice. To reduce bacterial growth, ice used around food or in food or drink must be made from potable water. All ice must be prepared in a sanitary manner and afforded the same protection as potable water. The medical departments aboard ships are required to include ice samples in any bacteriological analyses they perform on water.

WASTEWATER TREATMENT AND DISPOSAL

Wastewater is the spent water of a ship, base, industrial plant, or other activity. This spent water contains wastes, such as soil, detergent, and sewage. The proper disposal of these waste materials is one of the most important measures for controlling water-borne diseases, such as cholera and typhoid fever.

Wastewater Treatment and Disposal Systems Ashore

The use of approved municipal or regional wastewater collection and disposal systems is the preferred method for disposing of wastes from shore activities. Accordingly, municipal or regional wastewater disposal systems are used by Navy shore yes"> activities whenever feasible.

Wastewater Treatment and Disposal Systems Afloat

The overboard discharge of untreated sewage from DoD ships within the navigable waters of the United States and the territorial seas (within three nautical miles of shore) is prohibited by federal law. To comply with the law, naval vessels are being equipped with marine sanitation devices (MSDs) that either treat sewage before discharge or collect and hold it until it can be properly disposed of through dockside sewer yes"> connections or pumped overboard in unrestricted waters. For more detailed instruction on these topics, you should review Manual of Naval Preventive Medicine, NAVMED P-5010.

SECTION SUMMARY
This section discussed basic information pertaining to sanitation, habitability management, pest and vector control, food-borne illness, food-service sanitation, food-service inspections, and food-borne illness outbreak investigations.

We also discussed communicable diseases, water supply, and wastewater treatment and disposal procedures. This section discussed information on the safe and proper handling of potable water, bacterio- logical tests, treatment, and disinfection. A general review of wastewater treatment and disposal procedures for shore and afloat activities was also included in this section.

SUMMARY
This chapter has provided a general overview on a variety of fundamental dental conditions and preventive medicine situations. Because of the nature of our rating and the many responsibilities placed upon us, Hospital Corpsmen must have a general under- standing of many areas of medicine. Dentistry and preventive medicine practices are two of those areas. For additional detailed information on these subjects, you should refer to the References listed at the beginning of this chapter.