1. Wuchereria and Brugia
The four most common clinical presentations of lymphatic filariasis (involving Wuchereria and Brugia) include:
- Asymptomatic microfilaremia (also known as subclinical)
- Lymphedema
- Hydrocele (fluid-filled sac, around testicles causing scrotal swelling in males)
- Acute attacks (when adult worms block lymphatic channels causing inflammation)
And less frequently:
- Chyluria (seen when lymphatic fluid leaks into kidneys and the urine appears milky white)
- Eosinophilia (known as pulmonary eosinophilia syndrome, causing cough, shortness of breath, and wheezing)
- Presence of microfilariae in aspirates from joint spaces, brain breast, nipple, cervicovaginal smears, and ovarian cyst fluid8
Most cases are asymptomatic; however,
- itchy skin,
- chest/muscle pain (myalgias), or
- swellings may occur. (Long-term infection may permanently damage the lymph system - causing swelling to legs, arms, and genitalia. A thickening of the skin is seen in elephantiasis.)
2. Loa loa
Loa loa multiply in the subcutaneous tissue and then migrate. Clinical presentations include:
- Swellings in extremities, edema
- Impaired vision
3. Onchocerca
Onchocerca infection begins wherever the larvae are deposited. Their migration occurs in tissues, not in the lymphatic system. Clinical presentations include:
- Nodules in the skin
- Itching (Metabolites of worms cause inflammation as the worms migrate)
- Eye (Corneal lesions; microfilariae may be seen in the conjunctiva); dead microfilariae cause an immunological reaction. Blindness is common in untreated infections.
4. Mansonella
Mansonella infection begins when the larvae enter the bite wound. Most infections seem to be asymptomatic. However:
- Headache, fever, and pulmonary symptoms have been associated with M. ozzardi infection.
- Skin rashes and pigment changes may occur in M. streptocerca infection. (Caused by inflammation around microfilariae)
- Filariae invade peritoneal or pleural cavities in M. perstans infection. Right upper quadrant or abdominal pain may be associated with this infection.
8. Rohini Dhanya CS, Jayaprakash HT. Microfilariae, a common parasite in an unusual site: A case report with literature review. Journal of Clinical and Diagnostic Research. JCDR. 2016;10(4), ED08. Accessed April 6, 2023. https://pubmed.ncbi.nlm.nih.gov/27190816/ 9. CDC/Ruebush. Image #16438. "This child presented to a clinical setting with a case of filariasis, a parasitic disease caused by the microscopic, thread-like worms,
Wuchereria bancrofti,
Brugia malayi and
Brugia timori. Note the marked swelling of the child’s left leg, due to the leg’s worm-clogged lymphatic system. This build-up of lymph in the leg tissues is known as lymphedema." PHIL public domain. Created 1977. Accessed April 6, 2023.
https://phil.cdc.gov/Details.aspx?pid=1643810. CDC/Craig. Image #20286. "This medial view of the right leg of this Nigerian man, revealed numerous cutaneous lesions, which were determined to be due to a chronic onchocerciasis infection, caused by the microfilarial parasite, Onchocerca volvulus." PHIL public domain. Created 1967. Accessed April 6, 2023. https://phil.cdc.gov/Details.aspx?pid=20286
