MegaELISA® DIRO Antigen is an enzyme immunoassay for the qualitative detection of Dirofilaria immitis antigens in plasma or serum of the dog.

The dirofilariosis of the dog, cat, ferret as well as other carnivores, is caused by the so-called “heart worm”, a nematode of the filaria family named Dirofilaria immitis. Infection of humans (dead end host) is possible (zoonosis). The filaria manifest especially in lungs and conjunctive tissue, but are rarely diagnosed.

The transmission happens via infected, haematophagous mosquito species (Culicidae), releasing infectious D. immitis larvae (stage L3) in the host blood with the sting. After development of the larva (stage L4) in the hypodermis of the host (about 8 days post infection), they migrate into the blood circulation. The establishment of the adult worms (macrofilaria: up to 1 mm thick, 20–30 cm long) takes place earliest 80 days p. inf., most of all in the pulmonary artery and in the right heart chamber. The female adult parasite of the bisexual macrofilaria produce new larvae (stage L1, microfilaria) at first after 6 months. These are released together with antigens of the female reproductive tract to the peripheral blood (microfilaraemia) and are ingested again by mosquitoes at sucking action. In the mosquitoes, the larva 1 develops into an infectious larva 3.

The degree of disease depends on the quantity of adult worms (“worm burden”, normally more than 30), localization, duration of infection and the host’s immunological reaction.

First of all, dirofilariosis is a cardiopulmonary disease beginning without symptoms. In advanced stage, right-sided heart failure and Cor pulmonale occur with symptoms like cough, dyspnoea, heart and lung murmurs, oedemas as well as fast fatigue. Particularly in small dogs, in case of large “worm burden” the “vena cava syndrome” (obturation stenosis because of massive worm cluster in the posterior vena cava and the right atrium of the heart) occurs and thus leads to intravascular haemolysis, shock, kidney failure and sudden death.

Due to the rather difficult clinical diagnosis and the short and transient proceeding microfilaraemia, a repeated testing with MegaELISA® DIRO Antigen is recommended.

Being fast and reliable, the MegaELISA® DIRO Antigen detects group-specific antigens of the active reproductive tract of the female adult D. immitis worm. Due to the long incubation time of 6 months p. inf. (after stay in dirofilariosis regions), testing with MegaELISA ® DIRO Antigen should be carried out earliest 6 months after stay in dirofilariosis regions.

MegaELISA® DIRO Antigen is based on highly specific antibodies for the fast and reliable detection of Dirofilaria immitis in plasma or serum of infected dogs.