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USAID's NTD Program
USAID's NTD Program

Lymphatic Filariasis

Symptoms

LF can cause a broad range of clinical manifestations, varying from people with no evident clinical disease to those with lymphedema and/or severe disfigurement of the extremities (limbs) and genitalia. There is a huge potential of overlap in these symptom complexes, though an individual may also experience each at different times during his or her lifetime.

The majority of people infected by lymphatic filarial disease in endemic areas have few visible clinical manifestations despite the large number of circulating microfilariae in peripheral blood.1 Although almost all of those infected show no clinical manifestation, they have some degree of subclinical disease, which includes microscopic hematuria and/or proteinuria,2 as well as dilated and tortuous lymphatic vessels,3 and scrotal lymphangiectasia in men.4

Acute adenolymphangitis (ADL) is usually the first manifestation of LF, which occurs during adolescence. It is characterized by sudden onset of high fever, painful lymph node, lymphatic inflammation, and transient local edema. The retrograde nature of the lymphangitis distinguishes filarial-induced illness from bacterial-induced lymphangitis. Yet, involvement of the genital lymphatics appears quite exclusively with W. bancrofti infection. Previously, asymptomatic persons may have had an ADL episode that lasted four to seven days, with approximately one to three recurrences per year.5 However, in persons with pre-existing lymphatic disease of the affected extremities, episodes of ADL tend to be more severe and of longer duration.

Filarial fever may occur as an episode of acute fever in the absence of patent inflammation of the lymphatics. In endemic areas, filarial fever may be confused with other febrile manifestations, especially malaria. Epidemiological context and laboratory findings often are supportive of the diagnostic.

 

Photo of a man with swollen legs and scrotum.  
Source: Andrea Peterson  

Tropical Pulmonary Eosinophilia (TPE) is a syndrome that develops in some persons in their 30s, who are infected with either W. bancrofti or B. malayi.6 TPE affects more males than females with a 4-to-1 ratio, and the majority of cases have been reported in Southeast Asia, Pakistan, India, Sri Lanka, Brazil, and Guyana. Administration of diethylcarbamazine (DEC) leads to significant improvement in symptoms and an important decrease of eosinophilia as well as IgE. If not treated, TPE may progress to restrictive lung disease with interstitial fibrosis.7

Lymphedema of the limbs, genitalia, and breasts are common manifestations of lymphatic filarial infection. The World Health Organization has developed a grading system to quantify the severity of lymphedema of the legs.8

  • Grade I indicates pitting edema that is reversible upon elevation of the leg.
  • Grade II indicates non-pitting edema that does not reverse with elevation of the leg.
  • Grade III indicates an increase in the degree of swelling compared with Grade II and sclerosis and papillomatous changes in the skin. Grades II and III lymphedema are commonly referred to as elephantiasis.

Lymphedema of the genitalia usually involves swelling of the scrotum and/or thickening of scrotal or penile skin.9 Affected adult females living in endemic areas may experience unilateral or bilateral swelling of the breast.

Disease involving the male’s genitourinary system is the most common manifestation of LF due to W. bancrofti. Genitalia involvement is not common in Brugia infection. The prevalence of disease of the female genitalia is not yet known. Chronic disease of the male genitalia mostly produces hydroceles; the diameter of which may vary from 5 cm to more than 30 cm. Parasites are generally not found in the fluid.

Chyluria is a condition that is caused by obstruction or physiological impairment of the renal lymphatics, along with the passage of lymph into the genitourinary track. Patients may occasionally pass urine with a milky appearance. Chyluria may have serious nutritional consequences because large quantities of fat and protein are lost in the urine.

Learn more about lymphatic filariasis:

 

References

  1. Ottesen EA: Infection and disease in lymphatic filariasis: An immunological perspective. Parasitology 104:S71-S79, 1992.
  2. Dreyer G, Ottesen EA, Galdino E, et al: Renal abnormalities in microfilaremic patients with bancroftian filariasis. Am J Trop Med Hyg 46:745-751, 1992.
  3. Freedman DO, de Almeida Filho PJ, Besh S, et al: Lymphoscintigraphic analysis of lymphatic abnormalities in symptomatic and asymptomatic human filariasis. J Infect Dis 170:927-933, 1994.
  4. Noroes J, Addis D, Amaral F, et al: Occurrence of living adult Wuchereria bancrofti in the scrotal area of men with microfilaremia. Trans R Soc Trop Med Hyg 90:55-56, 1996.
  5. Pani SP, Yuvaraj J, Vanamail D, et al: Episodic adenolymphangitis and lymphoedema in patients with bancroftian filariasis. Trans R Soc Trop Med Hyg 89:72-74, 1992.
  6. Ottesen EA, Nutman TB: Tropical pulmonary eosinophilia. Annu Rev Med 43:417-424, 1992.
  7. Rom WN, Vijayan VJ, Cornelius MJ, et al: Persistent lower respiratory tract inflammation associated with interstitial lung disease in patients with tropical pulmonary eosinophilia following conventional treatment with diethylcarbamazine. Am Rev Respir Dis 142:1088-1092, 1990.
  8. Lymphatic filariasis. Fourth report of the WHO Expert Committee on Filariasis. World Health Organization Tech Rep Ser 702:3-112, 1984.
  9. Dreyer G, Noroes J, Figueredo-Silva J, et al: Pathogenesis of lymphatic disease in bancroftian filariasis: A clinical perspective. Parasitol Today 16:544-548, 2000.