Vector-Borne Agents

Question 0

How is Lyme disease spread?

Answer 0

Black legged tick- lxodes scapularis (seasonal vector) summer. Lyme disease does not spread person to person. Bacteria is a spirochete Borrelia burgdorferi. Lxodes ticks are very small and often go unnoticed, more likely for bacteria to be transmitted after tick has been feeding for 2-3 days.

Question 1

What are the three diseases we learned about that are vector-borne bacterial agents?

Answer 1

1. Lyme disease
2. Rocky Mountain Spotted Fever
3. Plague

Question 2

What is the life cycle of tick and how is this important for Lyme disease transmission?

Answer 2

Ticks have two-year life cycle and four stages of tick development: eggs hatch into larvae, larvae develop into nymphs, nymphs progress to adults, female adults lay eggs. Tick takes blood meal in each step of maturation. Nymph form is most likely to transmit bacteria to humans. Nymphs feed during late spring and early summer. THAT is why most cases of Lyme disease occur in summer.

Question 3

What are the animal reservoirs for B. Burgdoferi?

Answer 3

In East and Midwest, most common animal reservoir is white-footed mouse. Deer are also important, bc they are principal host for adult tick.