Dogs get heartworm (Dirofilaria immitis) through the bite of an infected mosquito. Here's how the transmission process works:
1. **Infected Mosquito Bites:**
- Heartworm larvae, known as microfilariae, reside in the bloodstream of infected dogs. When a mosquito bites an infected dog, it ingests these microfilariae along with the dog's blood.
2. **Development in Mosquito:**
- Inside the mosquito, the microfilariae mature over a period of 10 to 14 days into infective larvae.
3. **Mosquito Bites Another Dog:**
- When the infected mosquito bites another dog, it transmits the infective larvae into the dog's bloodstream through the mosquito's saliva.
4. **Migration to Heart and Development:**
- Once inside the new dog's bloodstream, the infective larvae migrate to the heart and adjacent blood vessels, where they mature into adult heartworms over the course of several months.
5. **Adult Heartworms:**
- Adult heartworms can grow up to 12 inches in length and reside in the heart, lungs, and associated blood vessels of the infected dog. They reproduce and release microfilariae into the dog's bloodstream, perpetuating the cycle when a mosquito bites the infected dog and ingests these microfilariae.
It's important to note that heartworm disease can be prevented through regular use of heartworm preventatives prescribed by a veterinarian. These preventatives work by killing the immature larvae before they develop into adult heartworms, effectively breaking the transmission cycle and protecting dogs from infection. Additionally, regular testing for heartworm infection is recommended, as early detection allows for timely treatment and management of the disease.