Communicable Disease Program

What are Communicable Diseases?

Communicable diseases are diseases that spread from one person to another either directly or indirectly.

What Causes Communicable Diseases?

Communicable diseases are caused by several kinds of tiny life forms, often called “germs” that generally can only be seen by microscopes. The two most common kinds of life forms that cause diseases in humans are bacteria and viruses. Others include fungi, parasites and prions.

What Are the Differences Between Viruses and Bacteria?

Viruses are made up of proteins and small strands of genetic material. They can only reproduce themselves when they are infecting humans or some other kind of animal, insect or plant. Scientists have been able to develop vaccines to prevent many kinds of viral infections. They have been less successful at making drugs, called antivirals, to treat viral infections. Antibiotics do not work against viral diseases.

Bacteria are larger single celled life forms that can grow and reproduce independently. There are many different kinds of bacteria. Most bacteria are susceptible to antibiotics, but some bacteria have grown resistant to them.

How do bacteria and viruses pass from one person to another?

There are several ways disease-causing agents get from one person to another:

• Airborne or droplet infection. (e.g. colds, flu.)
• Animal borne or insect borne infection (e.g. rabies, malaria)
• Blood borne infection (e.g. HIV, hepatitis)
• Food borne or water borne infection (e.g. salmonella)
• Sexual Transmission (e.g. syphilis, gonorrhea, HIV, genital warts)
• Other Direct Contact (e.g. some kinds of body warts, scabies)
• Indirect Contact ( e.g. colds and flu carried from person to person on dirty tissues, money, computer keyboards, etc.)

A few common diseases and their methods of transmission are listed on the chart below:

Information on Some Common Communicable Diseases
(click here for printable PDF file of this information)

Disease	Cause	Method of transmission	Prevention	Treatment
Common cold	About 250 different viruses	Droplets from sneezes, coughs. Coming into contact with contaminated items like phones, computers, etc.	• No vaccine • Hand washing; • Staying away from the sick	None. You may take medicine to help with symptoms.
Seasonal influenza	Viruses	Droplets (see above)	Vaccine available, although not 100% effective.	None. Treat symptoms and rest. Antivirals may decrease length and severity of illness
Strep throat	Group A Streptococcal bacteria	Droplets (see above); indirect contact	• No vaccine. • Avoid the sick • Wash hands, etc.	Antibiotics
HIV	Human Immune Deficiency Virus	Sexual transmission; • Blood borne; • Perinatal (from Mom to unborn child)	• No vaccine • Several are under development • No sexual contact with infected person	Antiviral drugs developed specifically to fight HIV; they do not cure HIV, but prolong life.
Sexually Transmitted Dieseases caused by bacteria: • Syphilis • Gonorrhea • chlamydia	3 different kinds of bacteria	Sexual (through direct and intimate contact)	• No Vaccines • Avoid sexual contact • Use safer sexual practices	Antibiotics
Sexually Trans-mitted Diseases Caused by Viruses • genital warts • herpes • hepatitis B	3 different viruses	Sexual	• New vaccine • No vaccine • Vaccine!	Antivirals may used but are not curative.
Rabies	Virus	Animal borne	No vaccine	Nearly always fatal without vaccine
Salmonella	Bacteria	Food borne	• No vaccine • Cook food properly	None. Treat symptoms and rest
Athlete’s Foot	Fungus	Indirect contact (like sharing a shower)	Don’t go barefoot	Yes
Malaria	Parasite	Insect borne	• No vaccine • Pre-medication available for travelers • Insect repellant	Yes

More detailed information available through links below.

How can I prevent the spread of communicable disease?

• Take advantage of vaccines that are available to prevent serious illnesses.

• Practice good infection control

• When you are sick keep your germs to yourself and stay home from work or school.
• When you are well stay a safe distance (2 - 3 feet) from those who are sick.
• If you are given medication to treat an infection, be sure to finish your prescription. Stopping too soon may lead to resistance, making future infections harder to fight.
• Wash hands frequently and completely:

Hand washing is the single most effective method of preventing common infectious diseases!

• Proper Hand Washing Technique:
  • Thoroughly wet hands
  • Apply soap and lather for 15 – 20 seconds
  • Rub longer if hands are visibly dirty
  • Soap well every part of the hands (don’t forget between the fingers and under the nails)
  • Rinse in a flowing stream of water
  • Dry hands with paper towel or hand dryers

Hints:

• Obtain dry paper towels before actually washing hands
• Turn faucet off using a paper towel
• Activate hand dryers with elbow, rather than clean hands

• Use alcohol gel or hand rubs in place of soap and water only if hands are not visibly dirty and the solution contains at least 60% alcohol.

More information is available at the sites listed below:

Overview of specific diseases and conditions:

http://www.cdc.gov/node.do/id/0900f3ec8000e035
http://www.health.state.ny.us/

Information about sexually transmitted diseases:

http://www.cdc.gov/node.do/id/0900f3ec80009a98 http://www.health.state.ny.us/diseases/communicable/std/index.htm

Information about hepatitis:

http://www.cdc.gov/ncidod/diseases/hepatitis/
http://www.health.state.ny.us/diseases/communicable/hepatitis/

Information about HIV / AIDS:

http://www.cdc.gov/hiv/
http://www.health.state.ny.us/diseases/aids/index.htm