Dirofilaria immitis Hundens tropiske hjerteorm (Canine tropical heartworm)

Filarial heartworm in dogs: | Order: Spirurida | Superfamily: Filarioidea | Family: Onchocercidae

Giemsa stained blood smear from dog. Microfilariae (appr. 325 µm long) swimming in the blood plasma. For comparison, the microfilariae are e.g. 10-15 times larger than trypanosomes. Wide curved front part and pointed rear part. Contains different characteristical cells.

Hosts: Dogs, occasionally cats. Vectors (intermediate hosts): Mosquitoes (Culex, Aedes, Anopheles, Myzhorhynchus).   Infection occurs in the tropics and subtropical zones (e.g. Australia, India, South Africa, South America, Southern Europe, Southern Asia, and the US).

Location: Adult worms in the right ventricle and pulmonary artery.