Filariasis is a chronic parasitic disease caused by Wuchereria bancrofti and Brugia malayi transmitted by mosquitoes. The larvae of filariae, known as microfilariae, exhibit a strict nocturnal periodicity in the bloodstream. Adult worms reside in the lymphatic system and can clinically cause lymphangitis and obstructive symptoms. In advanced stages, it often leads to elephantiasis of the lower limbs. Wuchereria bancrofti can also frequently cause chyluria and symptoms of the genitourinary system.

bubble_chart Epidemiology

Filariasis is distributed in areas south of Shandong and Henan, with most endemic regions in China being of low to moderate prevalence. The infection rate is lower in children than in adults. Patients residing in endemic areas have a history of lymphangitis and lymphadenitis episodes.

bubble_chart Clinical Manifestations

Most pediatric patients are asymptomatic after infection, with microfilariae detected in the blood during screening. A few children experience periodic fever, often accompanied by lymphangitis and lymphadenitis (most commonly inguinal lymphadenitis, followed by centrifugal lymphangitis). The fever can exceed 39°C and last for 3 to 5 days, accompanied by general fatigue, dizziness, headache, lumbago, loss of appetite, nausea, vomiting, and systemic allergic symptoms such as urticaria, allergic rashes, and asthma. Advanced-stage symptoms like elephantiasis, chylous stranguria, or hydrocele of the tunica vaginalis are rare in children.

bubble_chart Auxiliary Examination

1. Increased white blood cells and eosinophils in peripheral blood.
2. Microfilariae can be detected in the child's peripheral blood during nighttime examination.
3. Positive reactions in immunological tests such as intradermal tests and complement fixation tests.
4. If conditions permit, lymphangiography can be performed, showing dilation of the afferent lymphatic vessels and narrowing of the efferent lymphatic vessels; defects in the lymph node parenchyma are evident.
5. Biopsy involves excising a small piece of suspected lesion tissue (such as superficial lymph nodes in the lower limbs or nodules in the spermatic cord) to search for adult worms.

bubble_chart Treatment Measures

Etiological treatment, the following drugs can be selected.

1. Hetrazan (diethylcarbamazine citrate) is the first choice, as it has a killing effect on both microfilariae and adult worms. The usual dosage is 5-10mg/(kg·d), divided into three doses taken after meals, for 7-15 consecutive days. Alternatively, 15mg/(kg·d), divided into three doses taken after meals, for 5 consecutive days. Short-course therapy is convenient for large-scale collective treatment, with a dose of 20mg/(kg·d), divided into two oral doses, for 2 consecutive days, followed by 10mg/kg once weekly, administered at draught, for 7 consecutive weeks. After taking Hetrazan, a large number of microfilariae in the blood are destroyed, often causing heterologous protein reactions due to their decomposition, such as chills, fever, rash, muscle and joint pain, etc., which usually subside within 3-5 days without the need to discontinue the medication.
2. Levamisole: the dose is 3-5mg/(kg·d), divided into two doses daily, for 5 consecutive days. This Yaodui is more effective against microfilariae.
3. Furapyrimidone: has a significant killing effect on both microfilariae and adult worms of Brugia malayi. The oral dose is 15-20mg/kg daily, divided into three doses taken after meals, for 5 consecutive days. Occasionally, fever, dizziness, headache, loss of appetite, and increased eosinophils may occur after taking the medication.

bubble_chart Prevention

1. Treat patients universally to eliminate the source of pestilence.
2. Eradicate mosquitoes, prevent mosquito bites, and maintain environmental hygiene.