Infection control

Definition

Infection control refers to policies and procedures used to minimize the risk of spreading infections, especially in hospitals and human or animal health care facilities.

Purpose

The purpose of infection control is to reduce the occurrence of infectious diseases. These diseases are usually caused by bacteria or viruses and can be spread by human to human contact, animal to human contact, human contact with an infected surface, airborne transmission through tiny droplets of infectious agents suspended in the air, and, finally, by such common vehicles as food or water. Diseases that are spread from animals to humans are known as zoonoses; animals that carry disease agents from one host to another are known as vectors.

Infection control in hospitals

Infections obtained in hospitals are also called nosocomial infections. They occur in approximately 5% of all hospital patients. This results in increased time spent in the hospital and, in some cases, death. There are many reasons nosocomial infections are common, one of which is that many hospital patients have a weakened immune system which makes them more susceptible to infections. This weakened immune system can be caused either by the patient's diseases or by treatments given to the patient. Second, many medical procedures can increase the risk of infection by introducing infectious agents into the patient. Thirdly, many patients are admitted to hospitals because of infectious disease. These infectious agents can then be transferred from patient to patient by hospital workers or visitors.

Infection control has become a formal discipline in the United States since the 1950s, due to the spread of staphylococcal infections in hospitals. Because there is both the risk of health care providers acquiring infections themselves, and of them passing infections on to patients, the Centers for Disease Control and Prevention have established guidelines for infection control procedures. In addition to hospitals, infection control is important in nursing homes, clinics, child care centers, and restaurants, as well as in the home.

The newest addition to the infection control specialist's resources is molecular typing, which speeds up the identification of a disease agent. Rapid identification in turn allows for timely containment of a disease outbreak.

Threat of emerging infectious diseases

Due to constant changes in our lifestyles and environments, new diseases are constantly appearing that people are susceptible to, making protection from the threat of infectious disease urgent. Many new contagious diseases have been identified in the past 30 years, such as AIDS, Ebola, and hantavirus. Increased travel between continents makes the worldwide spread of disease a bigger concern than it once was. Additionally, many common infectious diseases have become resistant to known treatments.

Problems of antibiotic resistance

Because of the overuse of antibiotics, many bacteria have developed a resistance to common antibiotics. This means that newer antibiotics must continually be developed in order to treat an infection. However, further resistance seems to come about almost simultaneously. This indicates to many scientists that it might become more and more difficult to treat infectious diseases. The use of antibiotics outside of medicine also contributes to increased antibiotic resistance. One example of this is the use of antibiotics in animal husbandry. These negative trends can only be reversed by establishing a more rational use of antibiotics through treatment guidelines.

Bioterrorism

The events of September 11, 2001 and the anthrax scare that followed in October 2001 alerted public health officials as well as the general public to the possible use of infectious disease agents as weapons of terrorism. The Centers for Disease Control and Prevention (CDC) now has a list of topics and resources related to bioterrorism on its web site.

Description

The goals of infection control programs are: immunizing against preventable diseases, defining precautions that can prevent exposure to infectious agents, and restricting the exposure of health care workers to an infectious agent. An infection control practitioner is a specially trained professional, oftentimes a nurse, who oversees infection control programs.

Commonly recommended precautions to avoid and control the spread of infections include:

• Vaccinate people and pets against diseases for which a vaccine is available. As of 2003, the vaccines used against infectious diseases are very safe compared to most drugs.
• Wash hands often.
• Cook food thoroughly.
• Use antibiotics only as directed.
• See a doctor for infections that do not heal.
• Avoid areas with a lot of insects.
• Be cautious around wild or unfamiliar animals, or any animals that are unusually aggressive. Do not purchase exotic animals as pets.
• Do not engage in unprotected sex or in intravenous drug use.
• Find out about infectious diseases when you make travel plans. Travelers' advisories and vaccination recommendations are available on the CDC web site.

Because of the higher risk of spreading infectious disease in a hospital setting, higher levels of precautions are taken there. Typically, health care workers wear gloves with all patients, since it is difficult to know whether a transmittable disease is present or not. Patients who have a known infectious disease are isolated to decrease the risk of transmitting the infectious agent to another person. Hospital workers who come in contact with infected patients must wear gloves and gowns to decrease the risk of carrying the infectious agent to other patients. All articles of equipment that are used in an isolation room are decontaminated before reuse. Patients who are immunocompromised may be put in protective isolation to decrease the risk of infectious agents being brought into their room. Any hospital worker with infections, including colds, are restricted from that room.

Hospital infections can also be transmitted through the air. Thus care must be taken when handling infected materials so as to decrease the numbers of infectious agents that become airborne. Special care should also taken with hospital ventilation systems to prevent recirculation of contaminated air.

Selected Infectious Diseases And Corresponding TreatmentDiseaseSymptomsTransmittalTreatmentChicken poxRash, low-grade feverPerson to personNoneCommon cold/ InfluenzaRunny nose, sore throat, cough, fever, headache, muscle achesPerson to personNoneHepatitisJaundice, flu-like symptomsSexual contact with an infected person, contaminated blood, food, or waterNoneLegionnaire's DiseaseFlue symptoms, peneumonia, diarrhea, vomiting, kidney failure, respiratory failureAir conditioning or water systemsAntibioticsMeaslesSkin rash, runny nose and eyes, fever, coughPerson to personNoneMeningitisNeck pain, headache, pain caused by exposure to light, fever, nausea, drowsinessPerson to personAntibiotics for bacterial meningitis, hospital care for viral meningitisMumpsSwelling of salivary glandsPerson to personAnti-inflammatory drugsRingwormSkin rashContact with infected animal or personAntifungal drugs applied topicallyTetanusLockjaw, other spasmsSoil infection of woundsAntibiotics, antitoxins, muscle relaxers

Key Terms

Acquired immune deficiency syndrome (AIDS)

A disease that weakens the body's immune system. It is also known as HIV infection.

Antibiotic

A substance, such as a drug, that can stop a bacteria from growing or destroy the bacteria.

Antibiotic resistance

The ability of infectious agents to change their biochemistry in such a way as to make an antibiotic no longer effective.

Bioterrorism

The intentional use of disease-causing microbes or other biologic agents to intimidate or terrorize a civilian population for political or military reasons.

Ebola

The disease caused by the newly described and very deadly Ebola virus found in Africa.

Epidemiology

The branch of medicine that deals with the transmission of infectious diseases in large populations and with detection of the sources and causes of epidemics.

Hantavirus

A group of arboviruses that cause hemorrhagic fever (characterized by sudden onset, fever, aching and bleeding in the internal organs).

Immunization

Immunity refers to the body's ability to protect itself from a certain disease after it has been exposed to that disease. Through immunization, also known as vaccination, a small amount of an infectious agent is injected into the body to stimulate the body to develop immunity.

Immunocompromized

Refers to the condition of having a weakened immune system. This can happen due to genetic factors, drugs, or disease.

Nosocomial infection

An infection acquired in a hospital setting.

Staphylococcal infection

An infection caused by the organism . Infection by this agent is common and is often resistant to antibiotics.

Vector

An animal carrier that transfers an infectious organism from one host to another.

Zoonosis (plural, zoonoses)

Any disease of animals that can be transmitted to humans under natural conditions. Lyme disease, rabies, psittacosis (parrot fever), cat-scratch fever, and monkeypox are examples of zoonoses.

For Your Information

Resources

Books

• Edmond, Michael B., and Richard P. Wenzel. "Infection Control." In Principles and Practice of Infectious Diseases, ed. G. L. Mandell, J. E. Bennett, and R. Dolin. New York: Churchill Livingston, 1995.

• Ashford, D. A., R. M. Kaiser, M. E. Bales, et al. "Planning Against Biological Terrorism: Lessons from Outbreak Investigations." Emerging Infectious Diseases 9 (May 2003): 515-519.
• Jacobson, R. M., K. S. Zabel, and G. A. Poland. "The Overall Safety Profile of Currently Available Vaccines Directed Against Infectious Diseases." Expert Opinion on Drug Safety 2 (May 2003): 215-223.
• Petrak, R. M., D. J. Sexton, M. L. Butera, et al. "The Value of an Infectious Diseases Specialist." Clinical Infectious Diseases 36 (April 15, 2003): 1013-1017.
• "Plagued by Cures." Economist, 22 November 1997, 95-97.
• Sehulster, L., and R. Y. Chinn. "Guidelines for Environmental Infection Control in Health-Care Facilities. Recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC)." Morbidity and Mortality Recommendations and Reports 52 (June 6, 2003) (RR-10): 1-42.
• Subramanian, D., J. A. Sandoe, V. Keer, and M. H. Wilcox. "Rapid Spread of Penicillin-Resistant Streptococcus pneumoniae Among High-Risk Hospital Inpatients and the Role of Molecular Typing in Outbreak Confirmation." Journal of Hospital Infection 54 (June 2003): 99-103.
• Williams, Rosamund J., and David L. Heymann. "Containment of Antibiotic Resistance." Science 279 (20 February 1998): 1153-1154.

• American College of Epidemiology. 1500 Sunday Drive, Suite 102, Raleigh, NC 27607. (919) 861-5573. http://www.acepidemiology.org.
• American Public Health Association (APHA). 800 I Street NW, Washington, DC 20001-3710. (202) 777-APHA. http://www.apha.org.
• American Veterinary Medical Association (AVMA). 1931 North Meacham Road, Suite 100, Schaumburg, IL 60173-4360. http://www.avma.org.
• Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov
• National Institute of Allergy and Infectious Diseases (NIAID). 31 Center Drive, Room 7A50 MSC 2520, Bethesda, MD, 20892. (301) 496-5717. http://www.niaid.nih.gov.

Sources: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group

The Essay Authors are Cindy L. A. Jones, PhD, Rebecca J. Frey, PhD.