Which tick is the primary vector for Lyme disease?

Which tick is the primary vector for Lyme disease?

• A. Ixodes scapularis
• B. Amblyomma americanum
• C. Dermacentor variabilis
• D. Rhipicephalus sanguineus

Answer: (A)

Lyme disease is transmitted mainly by a specific tick species that thrives in the northeastern and upper Midwest United States. The black-legged tick, Ixodes scapularis, is the primary vector in these regions. Its life cycle includes larvae, nymphs, and adults, with Borrelia burgdorferi (the Lyme bacterium) residing in the tick’s gut and migrating to the salivary glands during feeding. Because transmission typically requires the tick to be attached for a significant period (often more than 24–48 hours), the nymphal stage—small and easy to miss—accounts for most human infections, especially in spring and summer. The other ticks listed are associated with different diseases or contexts. Amblyomma americanum is linked to ehrlichiosis and other illnesses; Dermacentor variabilis transmits Rocky Mountain spotted fever; Rhipicephalus sanguineus is a common vector for pathogens affecting dogs and other animals. They are not the primary Lyme disease vectors in the United States, making Ixodes scapularis the best answer.

Lyme disease is transmitted mainly by a specific tick species that thrives in the northeastern and upper Midwest United States. The black-legged tick, Ixodes scapularis, is the primary vector in these regions. Its life cycle includes larvae, nymphs, and adults, with Borrelia burgdorferi (the Lyme bacterium) residing in the tick’s gut and migrating to the salivary glands during feeding. Because transmission typically requires the tick to be attached for a significant period (often more than 24–48 hours), the nymphal stage—small and easy to miss—accounts for most human infections, especially in spring and summer.

The other ticks listed are associated with different diseases or contexts. Amblyomma americanum is linked to ehrlichiosis and other illnesses; Dermacentor variabilis transmits Rocky Mountain spotted fever; Rhipicephalus sanguineus is a common vector for pathogens affecting dogs and other animals. They are not the primary Lyme disease vectors in the United States, making Ixodes scapularis the best answer.