BLOOD AND TISSUE ROUNDWORMS Wuchereria bancrofti Brugia malayi Loa loa (“eye worm”) Onchocerca volvulus (“convoluted filaria”) Mansonella ozzardi (“Ozzard’s filaria”) Mansonella perstans (aka Dipetalonema perstans) Disease caused Bancroftian’s filariasis Malayan filariasis Calabar or fugitive swelling Onchocerciasis River blindness Mansonelliasis ozzardi Periodicity Nocturnal (10 PM – 2 AM) Nocturnal (10 PM – 2 AM) Diurnal Non-periodic Non-periodic Non-periodic Habitat Lymphatic vessels and glands Lymphatic vessels and glands Subcutaneous tissue Skin and subcutaneous tissue Body cavities Body cavities Vectors Aedes Culex Mansonia Anopheles Aedes Culex Mansonia Anopheles Tabanid flies (Chrysops) Black flies (Simulium) Midges (Cullicoides) Midges (Cullicoides) Distribution Widely distributed, including the Widely distributed, including the West and Central Africa, esp. Africa, South America South America South America, Africa Philippines (Bicol region) Philippines Nigeria, Cameroon and Zaire “Onchocercoma” – subcutaneous nodules from host allergic response Little tissue reaction commonly not observed Clinical manifestations (caused by adults) Cellular reaction in lymph nodes and lymphatic channels gradual lymphatic obstruction lymphedema enlargement of involved extremities (“elephantiasis”) Genital organs: W. bancrofti > B. malayi Temporary migratory inflammation (thus “fugitive”) Swelling in patient’s eyes (“Bulge eye”/ “Bung eye”) Laboratory Diagnosis Diagnosis based on recovery of microfiliaria in blood films/lymphatic fluids (stains: Giemsa or Wright’s stain) Microfilaria are few in blood when most of the s/s are prominent If nocturnal periodicity, collect at midnight Control and Prevention Chemotherapy: Diethyl-carbamazine (DEC) for microfilariae Public education Early diagnosis and treatment Vector control Concentration procedures (for microfilariae) Knott’s concentration technique Membrane filtration Gradient centrifugation technique Lymph node or tissue biopsy (for adults) – stain with Hematoxylin and Eosin Serologic tests: indirect immunofluorescence (survey and research purposes only) Gabrielle Paul S. Pascual, RMT MICROFILARIA Wuchereria bancrofti Brugia malayi Loa loa Onchocerca volvulus Mansonella ozzardi Mansonella perstans Sheathed Sheathed Sheathed Unsheathed Unsheathed Unsheathed Sheath Anterior Bluntly rounded anterior Bluntly rounded anterior Rounded anterior end Cephalic space Short space devoid of nuclei Long cephalic space devoid of nuclei Very small or no cephalic space Body Graceful curve Stiff and kinky body covered with a transparent sheath Irregular curves, or may be slightly straight covered with thin transparent sheath Body nuclei Equidistant Large Irregularly distributed or appearing in clumps in some areas Large Irregularly distributed Tail Pointed posterior end devoid of nuclei Pointed caudal end Pointed posterior Tapered Terminal nuclei Absent Two prominent terminal nuclei at caudal end (diagnostic) Reach caudal end Absent Long Short No distinct space Absent Reach caudal end Gabrielle Paul S. Pascual, RMT
