Learn about the causes, symptoms, and treatment options for heartworm disease in dogs on vcahospitals.com -- your trusted resource for pet health information.

Aug 9, 2022 · In any patient with a positive antigen test result, a microfilaria test should be performed to determine microfilarial status, as dogs with large numbers of microfilariae may benefit from a …

Jun 25, 2023 · Microfilaria is the larval stage of heartworms that live in the blood vessels and heart of infected dogs. It can be detected in a simple blood test, and if left untreated, it can develop into adult …

Heartworms are caused by the parasite Dirofilaria immitis. Immature heartworms, called microfilaria, are ingested by female mosquitoes when feeding on infected dogs. While the microfilaria are living inside …

How is heartworm disease transmitted from one pet to another? The mosquito plays an essential role in the heartworm life cycle. Adult female heartworms living in an infected dog, fox, coyote, or wolf …

Apr 16, 2026 · Dogs cannot get heartworm disease directly from one another. As mosquitoes bite and take blood from an infected host (such as another dog, fox, wolf, or coyote), they ingest young …

Jun 22, 2021 · Heartworm is a potentially deadly parasite that is transmitted only by mosquitos, which pick up larval heartworms, called microfilaria, circulating in the bloodstream of infected animals.

May 13, 2025 · The AHS Canine and Feline Heartworm Guidelines, updated in 2024, recommend microfilaria testing for dogs annually alongside antigen testing, provide instructions for interpreting …

Jan 14, 2026 · Microfilariae reside in the blood of most, but not all, infected canids. Microfilariae (300-322 µm x 6.8-7.0 µm) are ingested by feeding female mosquitoes. After two molts (approximately 2 …

Apr 27, 2026 · Transmitted by mosquitoes, the disease is caused by a type of parasitic roundworm that infects and lives in a dog's heart, lungs, and blood vessels.