Filariasis

Disease/Syndrome
Filariasis
Category
Infection, Travel
Acute/Chronic
Acute-Moderate (not life-threatening)
Synonyms
Wucheria bancrofti filariasis; Brugia malayi filariasis; Brugia timori filariasis;
Biomedical References
Comments
INITIAL SYMPTOMS:
Episodes of fever, lymphadenitis, lymphangitis, and swelling of the leg, arm, or male genitalia; Episodes last 3-7 days beginning in adolescence or early adulthood; Chronic lymphedema can cause hydrocele, orchitis, and elephantiasis; [PPID, p. 3211]

FINDINGS:
The body's reaction to the adult filarial worm in the lymphatic vessels leads to chronic inflammation, lymphatic obstruction, and secondary bacterial infections. Lymphatic filariasis may cause epididymitis, hematuria, proteinuria, and arthritis. [Merck Manual, p. 1346-7] Some of the different syndromes are: 1) asymptomatic and negative for parasites; 2) asymptomatic and microfilariae present; 3) acute recurrent lymphadenitis and retrograde lymphangitis; 4) lymphostasis (hydrocele, chyluria, and elephantiasis); 5) tropical pulmonary eosinophilic syndrome (nocturnal asthma, interstitial lung disease, recurrent fever, and no microfilariae in the blood). [CCDM, p. 211] Verrucous skin lesions and lymphorrhea are common in chronic cases. [Guerrant, p. 731-2] "Most infections are asymptomatic, but lymphatic dysfunction may lead to lymphedema of the leg, scrotum, penis, arm, or breast years after infection." [CDC Travel, p. 178]

ADENOLYMPHANGITIS:
Patients with acute adenolymphangitis present with sudden onset of fever and painful, swollen lymph nodes. The lymphangitis is retrograde, moving away from the lymph nodes. Typically, patients have one-week episodes of fever and lymphadenitis several times a year. Dermatolymphangioadenitis is an acute disease variant with high fever, myalgias, headache, and inflammatory skin lesions (vesicles, ulcers, and hyperpigmentation) often diagnosed as cellulitis. [Guerrant, p. 731-2]

TPE:
Tropical pulmonary eosinophilia (TPE) is uncommon. TPE is the pulmonary reaction to microfilariae in the capillaries and may progress to pulmonary fibrosis. Patients with TPE have marked eosinophilia, low-grade fever, and episodes of wheezing. [Merck Manual, p. 1346] In TPE, W. bancrofti and B. malayi infections cause fever, splenomegaly, lung infiltrates, and eosinophilia. In TPE, no microfilariae are present, probably destroyed by the immune system. [Cohen, p. 1917] Patients with TPE have coughing and wheezing, especially at night, and may have infiltrates, cavitation, and eosinophilic pleural effusion. Other symptoms of TPE are weight loss, eosinophilia, fever, and adenopathy. [Guerrant, p. 945]

EPIDEMIOLOGY:
Humans are reservoirs. Cats, civets, and primates are reservoirs of limited significance in Malaysia, southern Thailand, the Philippines, Timor-Leste, and Indonesia. [CCDM, p. 212] TPE is an uncommon complication with most cases reported in India, Pakistan, Sri Lanka, Brazil, Guyana, and Southeast Asia. The risk of lymphatic filariasis for the traveler is extremely small, given the inefficiency of transmission. [Guerrant, p. 733]

For updated text and symptoms of infectious diseases, see iddx.com.
Latency/Incubation
Microfilariae appear in blood: 3-6 months (B. malayi); 6-12 months (W. bancrofti); [CCDM]
Diagnostic
Giemsa stain of blood smear or detect live worms under microscope; Concentrate microfilariae by filtration of anticoagulated blood; [CCDM] Serology (EIA & RAPID); RAPID available from NIH (301-496-5398); [Harrison ID, p. 1116]
ICD-9 Code
125
ICD-10 Code
B74
Effective Antimicrobics
Yes
Reference Link

Symptoms/Findings, Job Tasks, and Agents Linked to This Disease

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Agents

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