Histopathological changes in liver of mice after experimental envenomation with androctonus amoreuxi scorpion venom

A total of 78 adult male Albino mice were divided into thirteen groups [6 mice in each]. One served as a control group and the other twelve groups were venom treated groups. The mice of treated groups were injected with 0.1 ml saline solution in which a particular amount of scorpion venom. The first 6 groups were subcutaneously injected with 1/2 LD50 [0.05 microg/g body weight], while the other 6 groups were injected with 1/4 LD 50 [0.025 microg/g body weight] by the same route. The animals from each group were anesthetized with ethyl ether and sacrificed at different time intervals [3, 6, 9, 12 hrs, 4 and 7days post toxin administration]. The microscopic examination of liver tissue obtained from envenomed animals showed variable histopathological changes being severely increased with the time interval of envenoming. The most obvious changes in the liver were acute cellular swelling, hydropic degeneration, congestion of central veins and portal blood vessels. Besides, extramedullary hematopoiesis and invaginations in nuclei of hepatic cells, with formation of intranuclear cytoplasmic inclusions were observed

Studies on rodents role as reservoir hosts of leishmaniasis with specical referance to their ectoparasites in Suez governorate

The distribution of rodents was studied in three different habitats. Seven rodent species were identified: Rattus norvegicus, R. alexandrinus, R. frugivorous, Mus musculus, Acoins russatus, Meriones sacramenti and Gerbillus pyramidum. The species distribution varied with the habitat type. The highest density of rodents was in July and August and the lowest one was in January. However, some species were collected all the year round. The rodents were investigated for the endo- and ecto-parasites. No Leishmania parasites were found. The ectoparasites were: Xenopsylla vita cheopis, Leptopsylla segnis and Ctenocephalides felis, Polyplax spinulos, Hyalomma dromedarii [nymph] and Echinolaelaps echidninus and Hemolaelaps glassgowi. Ecto-parasites were on rodents all year-round in domestic habitat and peridomestic habitats. In wild one, ecto-parasites activity was from March to December. The rodents' role as reservoir for L. najor was experimentally studied. Rodents inoculated with L. major together with hamster and BALB-c mice developed cutaneous lesions. The active lesions, the rodents' ecological habitats and the presence of insect-vector may pave the way to an epidemic zoonotic leishmaniasis role

Comparative exsheathment of microfilariae of wuchereria bancrofti in certain mosquito species

The exsheathment of ingested microfilaria [mf] of Wuchereria bancrofti in their vector Culex [Cx.] pipiens and in a refractory mosquito species Aedes [Ae.] caspius was assessed. No exsheathed mf was encountered in mid gut of tested mosquitos, while they were observed in abdomen and thoracic muscles. All exsheathed mf migrated from the mid gut of both tested species. The lowest percentage of ingested mf was recorded in the mid gut of Cx. pipiens and the thoracic muscles of Ae. caspius 1 day post feeding. On the other hand, 94.2% out of the exsheathed mf reached the thoracic region of Cx. pipiens and 1-tenth of this proportion was observed in the thorax of Ae. Failure of a large percentage of mf to exsheath after being ingested in the Ae. caspius indicated inefficient vector ability to support the filarial development to the infective stage

ultrastructure of the foregut and its influence on bancroftian microfilariae ingestion in three Egyptian mosquito species

Laboratory observation on the uptake of bancroftian microfilaria [mf.] by 3 Egyptian mosquito species revealed that microfilaria ingested by some tested species were badly damaged during ingestion. The foregut structures in Culex pipiens, Aedes caspius and Anopheles multicolor were investigated by light and scanning microscope techniques. In Ae. caspius, which has well developed pharyngeal armatures, and An. multicolor, which has well developed cibarial armature, high proportion of microfilaria was scored and damaged. Vice versa, Cx. pipiens, considered as the main vector of bancroftian filariasis, had neither developed pharyngeal nor cibarial pumps, the percentage of damaged mf was very small. The relationship between the injury of mf in mosquito midgut and the presence of the foregut armatures was discussed