Biomedical Technology Unit 5

Infectious Disease

a disease that is caused by the invasion of a host by agents whose activities harm the host's tissues and can be transmitted to others.

Pathogen

microorganism capable of causing disease

Opportunistic Pathogens

Only cause disease in a host with a weakened immune system

Infection

When a pathogen invades and beings growing within the host

Disease

When the growth of the pathogen causes damage to the host's tissues

What are the most dangerous agents?

Those that are virulent

virulent

Very likely to cause serious disease

Name three natures of infectious diseases:

non-Virulent and easy to transmit; virulent and hard to transmit, or both virulent and easy to transmit

In order to cause disease, pathogens must be able to:

Enter the host body

-adhere to certain host cells

-invade and colonize host tissues

-cause damage to those tissues

Pathogens typically enter the host through natural openings such as:

-mouth

-eyes

-genital openings

-wounds

Five major types of infectious agents

-bacteria

-viruses

-fungi

-protozoa

-helminths

-prions

Three common morphologies:

-Bacillus

-Coccus

-Spirella

Examples of bacteria:

-Staphylococcus aureus

Causes skin, wound, and respiratory infections

-Yersinia pestis

Causes plague

What causes TB

Mycobacterium tuberculosis

What are some common symptoms for TB?

• a cough sometimes blood tinged

• weight loss

• night sweats

• fever

True or False: Apart from a host cell a virus cannot metabolize or reproduce

True

What kind of strands do viral genomes have?

Double or single strands (DNA or RNA)

What kind of virus is HIV

Retrovirus

True or False: Viruses have long latent periods in which host shows no tissue damage while the virus reproduces.

True

Examples of DNA Viruses

-Herpes viruses

-Pox viruses

Fungi particle

mostly multi-cellular, can be unicellular

Where can you get protozoa?

contaminated, food, water, through the bite of an arthropod

Helminths

Simple invertebrate animals some of which are parasites

Prions

infectious particles consisting of only protein

Bovine Spongiform Encephalopathy

Mad Cow Disease

Epidemiology

study of occurrence of disease in populations

Disease Reservoir

The reservoir for a disease is the site where the infectious agent survives.