ABSTRACT
Objective: To evaluate the in vitro antischistosomal activity of two new synthetic benzimidazole-related compounds: NBTP-OH and NBTP-F. Methods: Schistosoma adult worms were recovered from mice infected with Schistosoma mansoni cercaria, washed and then incubated in the culture media with different concentrations of compounds NBTP-OH and NBTP-F up to 72 h. Scanning electron microscopy was conducted to report morphological changes. Results: Incubation of adult Schistosoma mansoni with 10 µg/mL of NBTP-OH for 48 h killed 81.25% of worms. The calculated LC50 and LC90 72 h post-incubation were 6.8 µg/mL and 9.8 µg/ mL, respectively. Exposure of worms to 10 µg/mL of NBTP-F killed 89.5% of worms after 48 h, mostly males (83.3%), the LC50 and LC90 after 72 h of incubation were 4.8 µg/mL and 6.9 µg/mL, respectively. Worms incubated for 72 h with these compounds revealed swelling and deformity of oral sucker, disorganization and erosion of the tegument when examined with scanning electron microscopy. Conclusions: NBTP-OH and NBTP-F possess in vitro antischistosomal activities; however, in vivo studies should be conducted to examine their antischistosomal effects.
ABSTRACT
During parasitological examination of Biomphalaria pfeifferi snails obtained from Niger state [Nigeria], 2 new types of cercariae were found. They are identified to the level of referring to the major group and described here for the first time. They were examined viable and stained with vital stains as well as fixed in 70% alcohol. They were drawn with a camera lucida and photographed. They are identified as an echinostome cercaria and a xiphidiocercaria. The echinostome is characterized by having a ventral sucker almost double in size the oral one. It has a semicircular structure located beyond the oral sucker. Three pairs of penetration glands are found at the anterior portion of the body. The number of collar spines is relatively large [44-46]. The flame cells are 17x2 in number. Two main lateral excretory ducts extend anteriorly, form two typical echinostome loops then pass posteriorly to open together in a diverticulat-ed excretory vesicle. Its tail is relatively long and flattened with 3 fin folds. The tail [640 microm] is longer than the body [475microm].The xiphidiocercaria belongs to the [ornatae] group. It is relatively small [180.5x110microm] with a long stylet [3'0nm]. Its oral sucker is one and half times the size of the ventral sucker. Two excretory ducts extend posteriorly in both sides and become dilated and unite to open in a circular excretory vesicle. Tail is slender shorter than the body and has a dorso-ventral fin fold. Key words: Echinostome cercaria, xixphidiocercaria, Biomphalaria pfeifferi