Water decoction of the leaves of Andrographis paniculata killed in vitro the microfilaria of Dipetalonema reconditum in 40 min. Three subcutaneous injections of the extract into infected dogs at 0·06 ml per kg bodyweight reduced the number of microfilariae in blood by more than 85%. The larvae were not totally eliminated with more infections but the reduced microfilarial level persisted. No toxiceffect of the extract was observed in rabbits. The treated dogs became lethargic initially for a week, probably due to the mass killing of microfilariae.

Mortality and infectivity or Schistosoma mansoni cercariae were tested against various concentrations of controlled release copper sulphate (EC-8) and tributyltin fluoride (CBL-9B). The results indicate that survival of cercariae varied with concentrations of molluscicide and times of exposures. Statistical analysis reveals that LC50 and LC90 for EC-8 were 1·8mg/1/hour and 1·82 mg/1/hour while LC50 and LC90 for CBL-9B were 16·8 μg/1/hour and 21·7 μg/1/hour respectively. Sublethal concentration of both molluscicides reduced cercarial infectivity considerably. The doses of 0·25 to 0·5 mg/1/hour for EC-8 and 2·0 to 6·0 μg/1/hour for CBL-9B were found to be sufficient to inhabit cercarial penetration of the host skin.

Brugia-type microfilariae were noted in a Madras tree shrew, Anathana ellioti (Waterhouse) from Andhra Pradesh, India. This is a new host record, the first report from the genus Anathana and the second report from the tree shrews.

The surface microtopography of Calicophoron papillosum (Stiles & Goldberger) and C. calicophorum (Fischoeder), inhabiting the rumen of sheep, has been studied by SEM. In C. papillosum, conspicuous transverse ridges encircle the mid-body, gradually lessening dorsally towards the posterior end. The general body surface is aspinose and smooth except for minute bead-like tubercles in the circumoral area. Two types of putative sensory structures—domed aciliate papillae and tegumental pits—are present. Their characteristic aggregation in certain regions and their distribution in other parts of the body is described. A unique pattern of ridges, confined only to the base of the genital papilla and the genital atrium, has been observed. In C. calicophorum, tegumental folds encircle the body, these are more numerous near the anterior end and fewer posteriorly. The oral area has numerous concentric folds with domed aciliate papillae; between or on the papillae are tegumental elevated pits from the centre of which a knob-like structure protrudes. These sensory structures occur to a lesser extent in the acctabular area.

Volume 56 no. 1, p. 69

The address for Dr. J. W. Mak should be:

Filariasis Research Division, Institute for Medical Research, Jalan Pahang, Kuala Lumpur 02-14, Malaysia.

The isoenzymes of acid and alkaline phosphatases and their histochemical localization were studied by polyacrylamide disc gel electrophoresis in four species of trematodes: Gigantocotyle explanatum from the liver and Gastrothylax crumenifer from the rumen of water buffalo (Bubalus bubalis) and Echinostoma malayanum and Fasciolopsis buski from the small intestine of the pig (Sus scrofa). Both acid and alkaline phosphatases were present in the tegument, gastrodermis, suckers, testes, ovary, eggs, vitellaria and uterus but alkaline phosphatase activity was demonstrated only in the parenchyma and excretory ducts. Polyacrylamide gel electrophoresis revealed two to four isoenzymes for both acid and alkaline phosphatase.

The habitat specificity of the acanthocephalan Acanthocephalus clavula in the alimentary tract of eels was studied in natural infections and in fish maintained experimentally under different regimes. The parasite exhibited a preference for a particular region (55 to 65%) of the alimentary canal which did not differ in different species of host, but habitat specificity was not very precise as there was considerable variation between individual hosts and A. clavula was capable of surviving and maturing in all regions of the intestine. The mean position of males was slightly anterior to that of females, and the over-all sex ratio was in favour of females. At high levels of infection the range of the parasites was extended and the mean position was significantly more anterior when compared to single worm infections. The parasite remains in the same site throughout the course of an infection: there was no posterior migration and gravid females occurred in the same proportion in all regions of the intestine. The mean position of the parasite did not change when the host was starved, or maintained in 100% sea water or with reduced aeration or at high temperatures. The results were compared with the habitat specificity exhibited by other species of freshwater fish acanthocephalans, and it was concluded that A. clavula was as adaptable and hardy as its present host, the eel.

The pathogenesis of H. contortus infection in lambs under 6 months of age challenged orally with 10,000 third stage infective larvae is described. The development of the parasite and its relationship to haematological and pathological changes are discussed, with particular reference to specific cellular mobilizations, and detailed descriptions are given of the haematology and parasitology, gross pathology and histopathology at 4, 7, 12, 18, 22 and 35 days after infection. Dramatic changes had developed by day 12.

Liver histology and serum enzyme and protein changes were studied in two strains of mice showing different initial susceptibilities to infection with Mesocestoides corti. The results show an increase in ALT and AST levels during the period of invasion and proliferation in the liver and a decrease in the levels of these two enzymes following encapsulation of the parasite in the liver and liver regeneration. A progressive loss of albumin was accompanied by increases in the levels of the beta- and gamma-globulins. These changes are discussed in the light of our knowledge of the effects of this parasite upon its host.

By transferring microfilariae of Brugia pahangi which had been born over a 24-hour period in the peritoneal cavities of jirds (Meriones unguiculatus) to the blood circulation of other jirds, infections of known age were tested for their ability to develop into third-stage larvae (L3) in mosquitoes Aedes aegypti. Microfilariae less than three days old were not able to develop to L3. Microfilariae which had been in circulation for three days to six months were capable of developing if ingested.

Dentostomella kuntzi is redescribed from specimens found in the rodent hosts Acomys cahirinus, Arvicanthis niloticus and Rattus rattus from the Giza province of Egypt, and compared with three species of the genus Dentostomella namely D. grundmanni, D. legerae and D. translucida. Unlike other species in the genus, the egg of D. kuntzi is operculate. The distribution of adult D. kuntzi within the intestine of Acomys cahirinus is also discussed.