LYMPHATIC PATHOLOGY IN WUCHERERIA-BANCROFTI MICROFILAREMIC INFECTIONS

To determine the extent of lymphatic disease in persons infected with Wuchereria bancrofti who were microfilaraemic, we examined the superfi cial lymphatics of the legs by scintigraphy. In 4 endemic control subj ects and in 10 of 14 clinically asymptomatic microfilaraemic individua ls, lymphoscintigraphy revealed one major channel of lymphatic drainag e in each leg. However, while trunk lymphatics were bilaterally symmet rical in the control, marked differences in the calibre of lymphatic v essels were observed in the microfilaraemic persons. Non-discrete lymp hatics and a diffuse symmetrical distribution of collateral vessels in both legs were observed in all of 5 amicrofilaraemic patients with gr ade 2 lymphoedema. A similar diffuse drainage pattern was also seen in 3 previously microfilaraemic persons who had remained amicrofilaraemi c and asymptomatic following treatment with diethylcarbamazine citrate (DEC). Thus, clearance of microfilaraemia by DEC therapy did not appe ar to reverse the type of lymphatic pathology observed in microfilarae mic subjects. The lymphoscintigraphy patterns did not correlate with s erum levels of antibodies to 3 recombinant filarial antigens. Virtuall y all the asymptomatic microfilaraemic individuals infected with W. ba ncrofti examined had subclinical lymphatic disease detected by the non -invasive imaging technique of lymphoscintigraphy.