How is dirofilariasis transmitted in dogs? - briefly
Dirofilariasis in dogs is typically transmitted through the bite of an infected mosquito. The parasite, Dirofilaria immitis, resides in the heart and pulmonary arteries of the dog, causing heartworm disease.
How is dirofilariasis transmitted in dogs? - in detail
Dirofilariasis, also known as heartworm disease, is a serious and potentially fatal condition in dogs caused by the parasitic worm Dirofilaria immitis. The transmission of this disease involves a complex life cycle that includes both an intermediate host and a definitive host. Here's a detailed breakdown of how dirofilariasis is transmitted in dogs:
-
Infected Mosquitoes: The primary vector for the transmission of heartworm larvae (microfilariae) is the mosquito. When a mosquito feeds on an infected dog, it ingests microfilariae present in the bloodstream. These immature worms then develop inside the mosquito over a period of 10 to 14 days, transforming into infective larvae (L3).
-
Bite Transmission: Once the larvae have matured within the mosquito, they are ready to be transmitted to another host. When an infected mosquito bites a dog, it injects the L3 larvae into the skin through its saliva. These larvae then enter the bloodstream and begin their journey towards the heart.
-
Migration to Heart: After entering the bloodstream, the L3 larvae migrate to the right side of the heart and the pulmonary arteries. This migration can take several months, during which time the larvae continue to develop into adult worms. The adults are typically found in the pulmonary arteries and occasionally in other parts of the circulatory system.
-
Reproduction: Once the adult worms have reached their final destination, they begin to reproduce. Female worms release microfilariae (immature larvae) into the bloodstream, continuing the life cycle. These microfilariae can then be ingested by mosquitoes feeding on an infected dog, starting the process over again.
-
Clinical Signs: The presence of adult worms in the heart and pulmonary arteries causes significant damage to these organs, leading to clinical signs such as coughing, exercise intolerance, decreased appetite, and weight loss. In severe cases, the disease can lead to congestive heart failure and even death.
Preventing dirofilariasis in dogs involves regular use of preventative medications that target the immature worms within the dog or the infective larvae transmitted by mosquitoes. These medications are typically administered monthly and are highly effective in preventing the disease. Additionally, controlling the mosquito population around the dog's environment can help reduce the risk of transmission.
In summary, dirofilariasis is transmitted through the bite of an infected mosquito, which introduces heartworm larvae into a dog's bloodstream. These larvae then migrate to the heart and pulmonary arteries, where they develop into adult worms and reproduce, continuing the life cycle. Effective prevention strategies are crucial in protecting dogs from this potentially fatal disease.