To study the morphology of microfilariae and laboratory diagnostic methods. To learn the morphology of T. spiralis. To master the pathogenesis of T. spiralis through animal experiment. Objectives and Requirements
Because these two species are similar in morphology,they will be discussed together,with notions on dissimilaritis.
Morphology Adult: White and thread-like. Two rings of small papillae on the head. Female: 5~10 cm in length, uterus almost occupies the body, uterus with eggs, mature eggs & larvae(microfilariae) Male: 2.5~4cm and a curved tail with two copulatory spicules.
Cephalic space sheath Body nuclei Excretory pore Terminal nuclei Nervous cycle Microfilaria: ＊ ＊ 177~296 µm in length with sheath, ＊ ＊ Anterior: bluntly rounded ＊ ＊ End: pointed ＊ ＊ A large number of nuclei could be seen in the body after staining.
Morphological Differences of Microfilariae between W. bancroti and B. malayi _______________________________________________________________ _ Species W. bancrofti B. malayi _______________________________________________________________ _ Appearance graceful, sweeping curves irregular, stiff curves _______________________________________________________________ _ Size larger 244-296× 7 µ m smaller 177-230 × 6 µ m _______________________________________________________________ _ Cephalic space shorter(1:1 or1:2) longer(2:1) (length:width) _______________________________________________________________ _ Bodynuclei equal sized, clearly unequal sized, over lapped, defined, countable uncountable _______________________________________________________________ _ Terminal nuclei no two _______________________________________________________________ _
A large number of larvae of a filarias emerging from the proboscis of a mosquito.
Diagnosis The diagnosis depends on the symptoms, signs and history of living in endemic areas, but the confirmative diagnosis depends on the demonstration of microfilariae 1. First choice method is thick blood smear, taking blood at night from 9pm-2am 2. Fresh blood smear used for mass education. 3. Immunological tests are only made reference of the diagnosis.
Morphology Adult small & slender with slightly tapered anterior end A pair of copulatory spicules at the posterior of the male male size: 1.4-1.6 plus 0.04- 0.05 mm female size: 3-4 plus 0.06 mm pharynx is one third or half of worm body long