Question

insect- and arachnid-borne diseases
the following chart lists some diseases that can be passed on to humans from insects (such as mosquitoes and flies) and arachnids (such as ticks and spiders).*

disease	carrier	type of germ	symptoms	severity
lyme disease	tick	bacterium	rash; fever; headache; body aches; fatigue; damage to heart, nerves, and joints	moderate to high
chagas disease	kissing bug	parasite	swelling; fever; body aches; headache; rash; nausea; vomiting; damage to the heart, esophagus, brain lining, and colon	low to moderate
dengue fever	mosquito	virus	fever, pain behind eyes, body aches, rash, bleeding	low, but can be severe for children
yellow fever	mosquito	virus	fever, chills, back and body aches, headache, nausea, bleeding, black vomit, low blood pressure, heart failure, coma, seizures	low to moderate
sleeping sickness	tsetse fly	parasite	fever, headache, body aches, irritability, fatigue, swollen lymph nodes, rash, confusion, personality changes	very high if untreated

*source: centers for disease control and prevention

strategy practice visualize and describe how a person with one of these diseases might appear.

skill practice read the item. write your response.

1. which insect in the chart is responsible for spreading the most diseases? how do you know?

Explanation:

1. Determine the insect with most diseases

To solve this, we count the number of diseases each insect (carrier) spreads:

• Mosquito: malaria, dengue fever, yellow fever → 3 diseases.
• Tick: Lyme disease → 1 disease.
• Kissing bug: Chagas disease → 1 disease.
• Tsetse fly: sleeping sickness → 1 disease.

Since 3 > 1, the mosquito spreads the most diseases.

Answer:

The insect responsible for spreading the most diseases is the mosquito. We know this because we count the number of diseases associated with each carrier: the mosquito is linked to malaria, dengue fever, and yellow fever (3 diseases), while the tick, kissing bug, and tsetse fly are each linked to only 1 disease.