1. BIOMEDICAL TECHNOLOGY BT06.01
Infectious Diseases
BIOMEDICAL TECHNOLOGY
BT06.01
Part One

3. Healthcare workers are responsible for providing care that utilizes INFECTION CONTROL principles that provide a safe environment.
This unit discusses infection control
principles as related to :
Microorganisms, pathogens, infection and colonization, chain of infection (how it’s spread), normal defense mechanisms, stages of the infectious process and nosocomial infections (hosp. acquired)

5. Infection / Infectious
An invasion or multiplication of micro organisms or infectious agents in the body tissues

6. Infectious Disease
An Infectious Disease is a disease that is caused by the invasion of a “host” (PERSON OR ANIMAL) by agents whose activities HARM the host’s tissues.
They cause disease (by impairing normal tissue function) and can be transmitted to other individuals (they are infectious)
Disease can be defined as a change in structure or function within the body , OR, Any change from normal.

7. Vocabulary
Pathogens – Microorganisms that are capable of causing disease. (Types?)
Infection – Results when a pathogen invades and begins growing within a host.
Disease – results only if and when tissue function is impaired or abnormal (i.e. burns, skin lesions)

8. Infectious Process
The body has defense mechanisms to prevent infection and to prevent disease after infection occurs.
In order to cause disease, pathogens must be able to:
enter the host body,
adhere (“stick”) to specific host cells,
invade and colonize (grow on) host tissues,
and inflict damage on those tissues.

9. Infectious Process Cont.
Entrances to the host (person or animal):
mouth, eyes, genital openings, or wounds. Any open oriface in or on the body
Growth of pathogens or the production of toxins/enzymes cause disease.
Some normal flora prevent disease. Normal Flora lives in the intestine, skin, vagina, and oral cavity.
They PREVENT OVERGROWTH OF
HARMFUL MICROORGANISMS
THEY ARE “GOOD BACTERIA”

10. Latent Period
A "latent period" is the lag time between exposure to a disease-causing agent and the onset of the disease the agent causes.
For instance, the latent period between exposure to HIV infection and the onset of AIDS may be many years.
Example: Magic Johnson
Another Example??

11. Some types of Microbes or Pathogens that cause infectious diseases Bacteria, Viruses, Fungi, Protozoa Ricketsiae, Helminth

12. BACTERIA
Small unicellular microorganism that mostly multiplies by cell division. Some produce Spores, resistant stage that can withstand an unfavorable environment. Resistant to heat, drying and disinfectants
Found as bacillus (rod shaped), coccus (spherical), or spirillum (spiral)
Ex: Staphylococcus, Streptococcus, E. Coli, Psudomonas, Salmonella, Shigella
Treatable with antibiotics

13. Bacteria Cont. Staphylococcus aureus (Staph)
-Favorite hangout: skin and nose
Likes: getting inside the body where it can cause a minor infection like a boil, or serious, sometimes fatal infections such as blood infections or pneumonia.
Dislikes: many antibiotics
MRSA-Methicillan Resistant Staph Aureus
Came about due to overuse of antibiotics, “bugs” mutate (changed) and became resistant to this specific antibiotic
VRE- Vancomycin-resistant Enterococci
Enteroccocci are bacteria that are normally present in the human intestines and in the female genital tract and are often found in the environment. Most vancomycin-resistant Enterococci infections occur in hospitals.

14. Bacteria Cont. AEROBES (Aerobic)
• Reproduces only in the presence of oxygen
ANAEROBES
Reproduce only in the absence of oxygen

15. BACTERIA EXAMPLES:
Gram positive [+] Changes color to lab stain STAPHYLOCOCCUS
Gram negative [-]
No change in color to lab stain
Salmonella

16. Staph infections
Impetigo- is a common and highly contagious skin infection that mainly affects infants and children. Impetigo usually appears as red sores on the face, especially around the nose and mouth, and on hands and feet. The sores burst and develop honey-colored crusts
Flesh eating “early. Another term flesh-eating bacteria refers to a type of very rare but serious bacterial infection known as necrotizing fasciitis. Necrotizing fasciitis generally starts in the tissues just below the skin and spreads along the flat layers of tissue (fascia) that separate different layers of soft tissue, such as muscle and fat. It is a dangerous and potentially deadly infection, most commonly occurs in the arms, legs, and abdominal wall It is fatal in 30%-40% of cases.

17. Flesh Eating bacteria ADVANCED

18. Yersinia Pestis (looks like Pests)
Bacterium that causes Plague
“Black Plague”
Transmitted via rodents
Plague is a disease that affects humans and other mammals. It is caused by the bacterium, Yersinia pestis. Humans usually get plague after being bitten by a rodent flea that is carrying the plague bacterium or by handling an animal infected with plague. Plague is infamous for killing millions of people in Europe during the Middle Ages. Today, modern antibiotics are effective in treating plague. Without prompt treatment, the disease can cause serious illness or death. Presently, human plague infections continue to occur in the western United States, but significantly more cases occur in parts of Africa and Asia.

19. VIRUSES common cold, measles/mumps, chicken pox, herpes, warts, polio, influenza, Mono, HIV,

20. Viruses Smallest of microorganisms
Apart from the host cell, they have no metabolism and cannot reproduce or survive unless they take over a living cell. (HOST)
Spread human to human
By blood & body secretions
Difficult to kill b/c they DO
NOT respond to antibiotics
What medicine would a
person need to take?

21. 3 Diseases of MAJOR concern to healthcare workers!
Hepatitis B- transmitted by blood, serum & other body secretions. Affects the liver & can destroy liver cells.
Hepatitis C- transmitted by blood & blood containing body fluids. Also causes destruction of liver cells.
 Human Immunodeficiency Virus / AIDS (Acquired Immune Deficiency Syndrome)- caused by the HIV virus. It suppresses the immune system so that person cannot fight off infections & some cancers. NO CURE & NO VACCINE!! Although new research looks promising for a vaccine

22. Retroviruses – a classification of viruses
HIV
Certain types of Cancer
Retroviruses are viruses whose genome consists of RNA not DNA.

23. Think about IT
• In February 1997 it was reported that pig cells contain a retrovirus capable of infecting human cells. This is troublesome because of the efforts that are being made to transplant pig tissue into humans (e.g., fetal pig cells into the brains of patients with Parkinson's disease/ Heart valves etc).

24. Virus Examples Chicken pox Cold sores Genital herpes Shingles
Small pox
AIDS
Influenza
Rabies-direct contact
West Nile Virus
Ebola →
Hantavirus
• Many viruses are preventable via vaccinations
• Can be treated with Antiviral drugs
• ANTIBIOTICS do not work

25. Smallpox virus Before smallpox was eradicated (eliminated), it was a serious infectious disease caused by the variola virus. It was contagious, meaning, it spread from one person to another People who had smallpox had a fever and a distinctive, progressive skin rash. Most people with smallpox recovered, but about 3 out of every 10 people with the disease died. Many smallpox survivors have permanent scars over large areas of their body, especially their faces. Some are left blind. Thanks to the success of vaccination, smallpox was eradicated, and no cases of naturally occurring smallpox have happened since The last natural outbreak of smallpox in the United States occurred in 1949.

26. More virus examples: Influenza Rhinovirus Measles Mumps↓
The common cold

27. Rotaviruses
Every year it kills approximately 1 Million children world wide
Why??
Gastroenteritis
Common in daycares
Rotavirus disease is most common in infants and young children. However, older children and adults also can get sick from rotavirus. Once a person has been exposed to rotavirus, it takes about 2 days for symptoms to appear.
Children who get infected may have severe watery diarrhea, vomiting, fever, or abdominal pain. Vomiting and watery diarrhea can last 3 to 8 days. 

28. FUNGI

29. Fungi “Fungus Among Us”
Have a cell wall and a cell membrane
Includes molds and yeast (“Candida Albicans”)
Treat with antifungal medication, sometimes with antibiotics.

30. Fungi examples Ringworm Histoplasmosis Athletes foot Thrush
What is Thrush?
Why does it grow?

31. Yeast or candida are opportunists
Yeast infections are the most common opportunistic infection
Antibiotics reduce normal flora and allow (give an opportunity) for yeast to grow, making the pt susceptible to an “opportunistic infection”

32. PROTOZOA
Acquired through contaminated food or water, or bite of an arthropod (mosquito)
More common in wet climates like the tropics
Causes “Amoebic dysentery” (diarrhea)
Malaria- is re-emerging d/t drug resistance and fear of vaccination
Treatable with antibiotics

33. HELMINTHS (PARASITIC WORMS) ewwww!
Simple, invertibrate animals, some infectious parasites
Pinworms and tapeworms are the most common.
SYMPTOMS: abdominal pain and diarrhea in intestines, blood, body tissues
Medications to force evacuation or death of worms.
Tapeworms are acquired by
eating uncooked or
inadequately cooked meat.

34. Trichinella spiralis (“roundworm”)
Swimmer’s itch in US
Schistosoma (“flatworm”)
Symptoms include abdominal pain and diarrhea
Trichinella spiralis (“roundworm”)
Ingested in undercooked pork from infected pigs.
Symptoms include vomiting, diarrhea, and abdominal pain
Pt. may die from respiratory paralysis -
SEE NEXT SLIDE FOR PICTURE!!!

35. Filariasis
Filariasis- worm infestation in lymphatic system that prevents normal draining of lymphatic fluids. Causes SEVERE swelling.

36. PRIONS (pree-ons) • Extremely small particles that consist
only of protein.
• Resistant to heat and
Disinfectants
• No known treatments
Creutzfeldt-Jakob disease
“mad cow disease” in cattle

37. Rickettsia
Parasitic microorganisms-CANNOT live outside the cell of other living organisms.
Commonly found in ticks, fleas, lice and mites.
Transmitted to humans from bites of these insects.
Causes diseases such as: Typhus fever, Rocky Mountain Spotted Fever (RMSF), Lyme Disease
Treatment is with antibiotics