Lab 31, Medical Asepsis, Effectiveness of Handwashing

What is a vector?

A vector is a living organism that transmits disease-causing organisms to another host, either directly (by biting) or indirectly (by carrying pathogens).

What are the two types of vectors?

• Biological vectors – transmit disease through biting (pathogen develops inside them)

• Mechanical vectors – carry pathogens on their body without being infected

What types of organisms are vectors usually?

Arthropods, including:

• Insects (mosquitoes, fleas, flies)

• Arachnids (ticks)

• Crustaceans (less common)

Why are mosquitoes important vectors?

They are the best-known insect vectors and transmit many major diseases.

What disease does the Anopheles mosquito transmit?

Malaria

Q: What diseases does the Culex mosquito transmit?

• West Nile virus (humans)

• Heartworm (dogs)

What diseases are associated with ticks?

Lyme disease (caused by Borrelia)

What is unique about the tick–Borrelia relationship?

The bacteria can live inside the tick and be transferred between hosts.

What are other examples of insect vectors?

• Fleas

• Deer flies

• Kissing bugs

• Tsetse flies

What is medical asepsis and its goal?

Medical asepsis (clean technique) reduces the number and spread of microorganisms to prevent infection, but does not eliminate all microbes.

: Give examples and settings of medical asepsis.

Handwashing, gloves, cleaning surfaces, proper waste disposal; used in hospitals, clinics, and routine patient care.

What are aseptic techniques and why are they important?

Practices that prevent contamination by microorganisms; they protect patients, healthcare workers, and lab samples from infection.

When are aseptic techniques critical + examples?

During invasive procedures or contact with open body sites (catheters, IVs, surgery, wound care).

Difference between medical asepsis and surgical asepsis?

• Medical asepsis = reduces microbes

• Surgical (sterile) asepsis = eliminates all microbes

What is Serratia marcescens and key features?

A red/pink-pigmented bacterium found in water, soil, and bathrooms; used in labs and can be opportunistic.

What is the purpose of this lab?handwashing

To see how well handwashing removes microbes by comparing bacteria growth before and after washing.

What is Veal Infusion Agar?

An enriched medium that helps many types of bacteria grow for observation.

Normal flora vs transient flora?

• Normal: permanent, hard to remove, protective

• Transient: temporary, easy to remove, cause infections

What are HAIs (nosocomial infections)?

Infections spread in healthcare settings due to poor hand hygiene.

Why is handwashing effective?

Soap breaks down oils and scrubbing physically removes microbes.

Key handwashing rule?

Scrub at least 20 seconds and clean all areas (especially under nails).

Surgical scrub basics?

Remove jewelry, scrub hands/forearms, keep hands above elbows, avoid contamination.

Hand sanitizer vs soap?

• Sanitizer = kills microbes

• Soap = removes microbes (better when dirty)