Emerging and RE-Emerging Infectious Disease

In Medieval times disease was seen as punishment from God.

AIDS???????

Germ Theory ( Bacterial Pathogens)

1- Organism always present in sick animals. 2- Organism Can be isolated and grown in a

pure culture. 3-When culture is introduced to health animal

it must cause sickness. 4-Organism re-isolated from healthy animal

must be same as original animal.

Bacterial Diseases

Disease Year Discovered Scientist

anthrax 1876 Kotch

gonorrhea 1879 Neisser

tuberculosis 1882 Kotch

plague 1894 Kitasato,Yersin

Whooping cough 1906 Bordet,Gengoe

Other pathogens

Virus- (made of Protein and nucleic acid) require a host cell to reproduce.-ex. Yellow Fever

Fungi- ex.- athletes foot, yeast infections. Parasites- Live at the expense of other organisms –

protozoa ex. malaria and helminths(from the round worm or flat worm phyla) ex. Hook worms

Prions????? Unusual proteins may be a pathogen.

Prevention and treatment

Survivors of disease become immune Chinese “valorization ” using dried material from

Small Pox sores.( risk of severe infection) Edward Jenner uses cow pox in immunize against

Small Pox( much safer) Louis Pasteur- develops immunization against

anthrax( bacterial Pathogen) and Rabies( viral pathogen) he also discovers that heating or “pasteurizing” liquids kills potentially harmful bacteria.

Antibacterial Drugs( Antibiotics)

Kill microbes without killing the patient. Alexander Fleming – Penicillin produced from

mold – kills staphylococcal bacteria Antibiotics flourished after WWII and many

infectious diseases were eradicated. Anti-viral meds are more difficult because

viruses reproduce within the cells of the host. Most meds would harm the healthy cells while trying to kill the virus.

Emerging Diseases

New diseased not seen before- Escherichia coli strain0157:H7- sickness and death in the 1990’sEbola hemorrhagic fever- 50- 90% Fatality rate. Appeared in the Congo in 1976.AIDS- Emerges simultaneously in US and Africa in 1980’sWhat do you think might explain the emergence of these “new pathogens”???

Re- Emerging diseases

Diseases that were previously controlled are making a “comeback”.

WHY???? Les strict enforcement of immunization programs and other

public health programs , Antibiotic resistant pathogens have evolved.

Tuberculosis and Malaria – major killers world wide Staphylococcus aureus- causes Bacterial

Pneumonia and is immune to ALL known antibiotics Could we be heading for another “pandemic era”???