Reference Manual - IARC Screening Group

Preventing Infections in Healthcare WorkersTHE DISEASE TRANSMISSION CYCLETeaching healthcare workers how to protect themselves and their patientsis more important than ever. If they know how to protect themselves anduse IP measures consistently, they will help protect their patients as well.The first step in this process is to understand how diseases are spread.Knowing the disease transmission cycle is important if healthcareworkers are to:• prevent the spread of infection during medical and surgicalprocedures,• teach others the factors required for transmission to occur, and mostimportantly,• teach others how to interrupt the process.Microorganisms live everywhere in our environment. Humans normallycarry them on their skin and in the upper respiratory, intestinal andgenital tracts. These microorganisms are called normal flora. Inaddition, microorganisms live in animals, plants, soil, air and water.Some microorganisms are more pathogenic than others, that is, they aremore likely to cause disease. Given the right circumstances, however, allmicroorganisms may cause infection.For bacteria, viruses and other infectious agents to survive and spreadsuccessfully, certain factors or conditions must exist. The essential factorsin the transmission of disease-producing microorganisms (pathogens) fromperson to person are illustrated and defined in Figure 5-1.Interrupting this cycle is the goal of IP practices. Most practices aimed atprotecting the healthcare worker (e.g., wearing gloves or eyewear) blockaccess to places of entry. Handwashing and procedures for processinginanimate objects block the method of transmission by removing themicroorganisms. Finally, vaccines reduce the susceptibility of the host,and prevent the disease even if the host is exposed.HOW RISKY HEALTHCARE WORK ISIn a recent US survey, only truck drivers and laborers were reported tohave higher on-the-job accident rates than healthcare workers (USDepartment of Labor 1995). Although exposure to biologic agents andsubsequent infection are not the only occupational hazards faced byhealthcare workers, infections, especially those caused by bloodborneorganisms, present the greatest risk. Contact with blood and body fluidsis the most common occupational risk faced by healthcare workers. Forexample, in the US alone, more than 800,000 needlestick injuries occur5-2 Cervical Cancer Prevention Guidelines for Low-Resource Settings