Dirofilaria repens Infection Inducing Constrictive-Effusive Pericarditis and Epicarditis Leading to Restrictive Cardiomyopathy in Dogs

“`html

Rare Heart Infection Linked to Parasitic Worm in Canine Case

A five-year-old, spayed female mixed-breed dog presented with progressive weakness and loss of appetite, ultimately leading to a heartbreaking outcome despite intensive veterinary intervention. The case, recently detailed by veterinary specialists, underscores the diagnostic complexities and potential severity of infections linked to the parasitic worm, *Dirofilaria repens*.

The dog,previously up-to-date on vaccinations and routinely treated for parasites,exhibited signs of severe illness including a distended abdomen and muffled heart sounds. Initial examinations revealed fluid accumulation around the heart and lungs, a condition known as pericardial effusion and ascites.

Diagnostic Challenges and Initial Treatment

Ultrasound imaging confirmed significant fluid buildup and identified abnormalities in the liver. Echocardiography revealed a substantial amount of fluid surrounding the heart,accompanied by a dangerous compression of the heart chambers-a state called cardiac tamponade.The initial treatment plan included antibiotics, diuretics to remove excess fluid, and corticosteroids to reduce inflammation.

While the dog initially showed some betterment, its condition rapidly deteriorated. Cytological analysis of the fluid surrounding the heart revealed inflammatory cells and, surprisingly, the presence of microfilariae-immature parasitic worms. However, standard blood tests did not detect these parasites in the bloodstream.

Confirming the Parasitic Link and Complex Therapies

Further testing,utilizing Polymerase Chain Reaction (PCR) technology,definitively identified *D. repens* DNA in the fluid surrounding the heart. This finding was particularly significant as a direct link between this parasite and pericardial effusion had not been previously established. Due to this anomaly, Veterinarians opted for a combined antiparasitic approach, utilizing three different medications alongside continued supportive care.

Despite repeated treatments and even surgical removal of part of the pericardial sac, the dog’s condition continued to decline. Post-mortem examination revealed extensive inflammation and scarring around the heart and lungs, along with the revelation of an adult *D. repens* worm within the abdominal cavity. Further analysis showed widespread inflammation affecting multiple organs.

Did You Know? *Dirofilaria repens* is typically associated with subcutaneous nodules, commonly known as “dog heartworm granulomas,” rather than direct heart involvement.

Key Findings Summary

Symptom	Finding
Initial Presentation	Progressive weakness, anorexia
Key Diagnostic Finding	Pericardial effusion with plankton sign (echogenic particles)
Parasite Identified	Dirofilaria repens DNA confirmed via PCR
Treatment Approach	Combination antiparasitic therapy, pericardiocentesis, surgery
Final outcome	Euthanasia due to persistent disease progression.

Implications for Veterinary Medicine and Pet Owners

This case highlights the need for vigilance and a broad diagnostic approach when dealing with unexplained heart conditions in dogs, particularly in regions where *D. repens* is prevalent.The unusual presentation underscores the parasite’s potential to cause more severe and atypical complications than previously understood.

Pro Tip: Regular heartworm prevention is critical, but it’s equally significant to discuss with your veterinarian the risk of *dirofilaria repens* and appropriate preventative measures, especially if you live in or travel to endemic areas. The CDC provides complete information on heartworm prevention.

What steps can veterinarians take to improve early detection of atypical *Dirofilaria repens* infections? How can pet owners advocate for thorough diagnostic testing when their animals present with unexplained heart problems?

Understanding *Dirofilaria repens*

*Dirofilaria repens*, commonly known as the subcutaneous filarial worm, is a parasitic roundworm transmitted to dogs (and occasionally cats and humans) through the bite of infected mosquitoes. While typically causing subcutaneous nodules, this case demonstrates its potential to induce more severe, life-threatening conditions. The parasite’s lifecycle involves mosquitoes acquiring microfilariae from an infected host, developing into infective larvae within the mosquito, and then transmitting these larvae to a new host during a blood meal.

Frequently Asked Questions about *Dirofilaria repens*