Microfilariae

In the photo, you see a microfilaria – a subcutaneous worm larva discovered yesterday in our clinic’s laboratory, found during a microscopic examination of an 8-year-old dog’s blood sample.

Microfilariae are transmitted by mosquitoes during a bite; they enter the bloodstream where they begin to develop, and adult helminths (dirofilariae – D. immitis) travel to the subcutaneous tissue or other organs such as the eyes, testes, lungs, or intestines. Although mosquitoes are only active in nature during the warm season, it is important to note that filariae are found in pets’ blood year-round. This is often an incidental finding because the larva’s development cycle lasts up to 7 months, and the parasite can live in the animal’s body for up to 4 years without showing any clinical symptoms.

Dirofilariae – roundworms that cause dirofilariasis in dogs – develop from microfilariae larvae. This subcutaneous dirofilariasis can cause itching, lethargy, hair loss, skin redness, the formation of skin nodules, or complications such as digestive disorders, neurological ailments, lung pathologies, etc.

These parasites are eliminated through medication and sometimes surgically.

To protect against these parasites, we recommend spraying your pet with mosquito repellent before every walk outdoors (especially when traveling to the forest, near bodies of water, etc.). It is important to mention that some products, such as tablets and drops against ticks, also act as a repellent against mosquitoes. So, here is another compelling reason not to forget to use tick protection once the weather warms up!