1. BIOMEDICAL TECHNOLOGY
Infectious Diseases
BIOMEDICAL TECHNOLOGY
Part One

3. OVERVIEW
* An Infectious Disease is a disease that is caused by the invasion of a host 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)

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

5. 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 to specific host cells, invade and colonize host tissues, and inflict damage on those tissues.

6. Infectious Process Cont.
Entrances to the host: mouth, eyes, genital openings, or wounds.
Growth of pathogens or the production of toxins/enzymes cause disease.
Some normal flora prevent disease.

7. 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

8. MICROBES THAT CAUSE INFECTIOUS DISEASES

9. BACTERIA
Small unicellular microorganism that multiplies by cell division.
Found as bacillus (rod shaped), coccus (spherical), or spirillum (spiral)
Anthrax, Cholera, Legionellosis, Lyme Disease, Salmonellas, Strep, TB, Typhoid, Yersinia pestis (plague)
Treatable with antibiotics

10. 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

11. Bacteria Cont. AEROBES • Reproduces only in the presence of oxygen
ANAEROBES
Reproduce only in the absence of oxygen
Facultative anaerobic bacteria:
can produce in either environment

12. BACTERIA EXAMPLES: Gram positive Gram negative – STAPHYLOCOCCUS
– SALMONELLA

13. Staph infections
Flesh eating early
Impetigo

14. Flesh Eating bacteria ADVANCED

15. Yersinia Pestis (looks like Pests)
Bacterium that causes Plague
Transmitted via rodents typically

16. VIRUSES

17. Viruses
Apart from the host cell, have no metabolism and cannot reproduce or survive unless they take over a living cell

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

19. 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/ hearts etc).

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

21. Smallpox virus

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

23. Rotaviruses Gastroenteritis Wheel shaped virus causing diarrhea
Every year it kills approximately 1 Million children world wide

24. FUNGI

25. Fungi Have a cell wall and a cell membrane Includes molds and yeast
Treat with antifungal medication, sometimes with antibiotics.

26. Fungi examples
Ringworm
Histoplasmosis
Athletes foot
Thrush

27. Yeast or candida are opportunists
Yeast infections are the most common opportunistic infection
Antibiotics reduce normal flora and allow yeast to grow making the pt susceptible to an opportunistic infection

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

29. HELMINTHS (WORMS) ewwww!
Simple, invertibrate animals, some infectious parasites
In intestine, blood, body tissue
Medications to force evacuation or death of worms

30. 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
SEE NEXT SLIDE FOR PICTURE!!!

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

32. 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