Raccoon heartworm causing a facial mass.

Area of Science:

• Parasitology
• Dermatology
• Tropical Medicine

Background:

• Dirofilaria tenuis is a filarial nematode typically found in raccoons and opossums.
• Human infections are rare, often presenting as subcutaneous nodules.
• Geographic distribution is linked to the prevalence of infected animal hosts.

Observation:

• A 77-year-old woman residing in Miami Beach presented with a supraorbital subcutaneous nodule.
• The nodule was surgically excised for diagnosis and treatment.
• The excised nodule contained a Dirofilaria tenuis worm.

Findings:

• Surgical removal of the subcutaneous nodule successfully treated the infection.
• Microscopic examination of the nodule confirmed the presence of Dirofilaria tenuis.
• The case highlights a rare instance of human dirofilariasis in Florida.

Implications:

• This case underscores the potential for zoonotic transmission of Dirofilaria tenuis to humans.
• Increased awareness among clinicians in endemic areas like southern Florida is crucial for prompt diagnosis.
• Understanding the parasite's life cycle and host interactions is vital for public health surveillance.