What causes dog heartworm and its known vector(s)?

What causes dog heartworm and its known vector(s)?

• A. The disease agent is Dirofilaria immitis and the vector is Ae. sierrensis and Ae. notoscriptus
• B. The disease agent is Dirofilaria repens and the vector is Cx. quinquefasciatus
• C. The disease agent is Wuchereria bancrofti and the vector is Anopheles gambiae
• D. The disease agent is Brugia malayi and the vector is Mansonia

Answer: (A)

The main idea is that dog heartworm is caused by a filarial worm called Dirofilaria immitis, and it is transmitted through mosquitoes. Infected dogs have microfilariae circulating in their blood, which mosquitoes ingest during a bite. Inside the mosquito, those microfilariae develop into infective larvae (L3), and when the mosquito feeds again, it transmits these L3 larvae to another dog. The larvae migrate to the heart and pulmonary arteries, mature, and cause disease. Certain mosquito species have been documented as vectors in different regions, including some Aedes species. The pairing presented reflects that Dirofilaria immitis is the agent and Ae. sierrensis and Ae. notoscriptus are known vectors in specific areas. Other options mix different filarial parasites with vectors associated with human diseases or different hosts, so they don’t match dog heartworm transmission. For example, Wuchereria bancrofti and Brugia malayi are human filarial parasites with other mosquito or aquatic beetle vectors in various regions, not the usual vectors for canine heartworm.

The main idea is that dog heartworm is caused by a filarial worm called Dirofilaria immitis, and it is transmitted through mosquitoes. Infected dogs have microfilariae circulating in their blood, which mosquitoes ingest during a bite. Inside the mosquito, those microfilariae develop into infective larvae (L3), and when the mosquito feeds again, it transmits these L3 larvae to another dog. The larvae migrate to the heart and pulmonary arteries, mature, and cause disease.

Certain mosquito species have been documented as vectors in different regions, including some Aedes species. The pairing presented reflects that Dirofilaria immitis is the agent and Ae. sierrensis and Ae. notoscriptus are known vectors in specific areas.

Other options mix different filarial parasites with vectors associated with human diseases or different hosts, so they don’t match dog heartworm transmission. For example, Wuchereria bancrofti and Brugia malayi are human filarial parasites with other mosquito or aquatic beetle vectors in various regions, not the usual vectors for canine heartworm.