In patients with filariasis, the illness starts as “Filarial fevers”. These are episodes of fever with chills and inflammation of the lymph glands particularly in the groin. Such episodes occur 6 to 10 times a year, and this fever subsides on its own in about three to five days. The lymph nodes during the episodes of fever are painful.
Repeated episodes over a period of time causes damage to the lymph glands. The extremities usually become swollen and skin changes are seen. The skin gets hardened. The limbs look like an elephant and is therefore called elephentiasis. Obstruction to the lymph drainage of the scrotum could lead to scrotal swelling and hydrocele.
Diagnosis and Treatment Definitive diagnosis can be made by demonstrating the filariae in the blood, and hydrocele fluid. Blood collection should preferably be done at night. The fluids can be examined directly after mixing with formalin and centrifugation of the fluid. Alternatively, filters are available through which the fluid can be passed and then examined under the microscope.
Serum Immunoglobulins, particularly IgE are raised in Filariasis. However, this test is non–specific and many conditions, particularly allergies can cause raised IgE. The same is true with finding a high number of eosinophils in the blood as these can be seen in many conditions. Thus, the diagnosis often rests on the clinical findings.
Is there any cure for filariasis? The drug DEC (diethyl carbamazine) is the mainstay of therapy for filiariasis. The dose is 6 mg per kilogram of body weight given as a single dose daily. The total duration of treatment is for about three weeks. Ivermectin is another drug that can be used. It is particularly useful against the parasites Bancrofti and Brigia.
What are the side–effects of treatment? At the start of therapy particularly in the first 24 to 48 hours, there can be fever, chills, nausea, vomiting and joint pains. It is not a direct, toxic effect of the drug but an allergic response of the body to dying parasites. To avoid this, lower doses can be used initially. For those patients whose disease is chronic and have developed elephantiasis, long term low dose DEC is used. Local care of the limb which includes elevation, using stockings or compression bandages to decrease the limb’s swelling may be tried.
Surgical measures can be tried such as excising redundant tissues, and decompression of the lymphatic system can be tried. Some therapies have also been tried like using ultraviolet light sessions to kill the microfilariae.