Ancylostoma ceylanicum is a new introduction as an experimental hookworm model. Information on the biology of this parasite in its laboratory host—the golden hamster, is meagre. Its infectivity, longevity and fecundity were studied to obtain relevant information especially on vulnerable points in the maintenance and continuation of the infection. 100% infectivity was obtained with an inoculum of 60 larvae per animal. Maximum numbers of parasites were harboured from day 15 to day 18 after infection and thereafter gradually declined. Approximately 10% of the worms were still present at the end of the third month of infection. The in vitro release of eggs in a 24-hour period by one female nematode peaked from day 25 to day 39; a second rise occurred on day 70 after infection.

Histopathological studies of Neoechinorhynchus hutchinsoni infection in Nemacheilus kashmirensis show partial or complete damage of the host intestinal wall, depending upon the degree of penetration. Increased number of goblet cells are seen at the site of unperforated wounds but where the intestinal wall is completely perforated the goblet cells were undifferentiated. The parasite destroys the mucosa, lamina propria, muscle layer and serosa leading to perforation. This report of perforation by Neoechinorhynchus hutchinsoni is the first in the genus Neoechinorhynchus.

The synthesis and filaricidal activity of l-iso-butoxycarbonyl-4-mcthylpipcrazinc against Litomosoides carinii in Sigmodon hispidus and Dipctaloncma viteae in Mastomys natalcnsis is reported. At an intrapcritoncal or oral dose of 3 mg/kg given for 6 days, the compound removed 91% of the circulating microfilariac but had no effect on adult L carinii. However, it killed all microfilariae and adults of D. viteae at a subcutaneous dose of 50 mg/kg given for 6 days. The compound also possessed ehemoprophylaetic activity against the larvae of L. carinii and D. viteae at a dose of 30 and 50 mg/kg respectively.

Lung infection with Angiostrongylus cantonensis was established in experimentally infected Indian softfurred rats (Millardia meltada) and Indian spiny mice (Mus platythrix). Pulmonary arterial migration occurred earlier (at day 20 after infection) in M. meltada than in Wistar rats. M. meltada and M. platythrix could serve as useful animal models for comparative studies of mechanisms determining host specificity of A. cantonensis.

Non-specific and specific phosphatases have been histochemically localized in the tissues of Avitellina lahorea, an intestinal parasite of sheep and goats. Large quantities of acid phosphatase, alkaline phosphatase and adenosine triphosphatase were observed in almost all organs except the parenchyma where there were moderate amounts of acid phosphatase and no alkaline phosphatase; the reproductive ducts contained moderate amounts of alkaline phosphatase. 5-nucleotidase was observed only in the uterus, egg pouches and eggs and glucose-6-phosphatase activity was restricted to the tegument. The probable functions of these moieties at different sites are discussed.

The utility of the IgG fraction of human filarial serum immunoglobulin in detecting circulating antigen by sandwich enzyme linked immunosorbent assay (ELISA) was studied. 27 of 33 sera from persons with microfilaracmia, 19 of 30 sera from clinical cases of filariasis, 4 of 30 sera from normal persons from a region endemic for filariasis showed the presence of circulating filarial antigen. All the 20 normal sera from the area where filariasis was not endemic gave negative reaction for filarial antigen. Those sera from persons with microfilaracmia that showed the presence of circulating antigen also showed an apparent positive correlation between the microfilarial density and the antigen titre.

The rate of glucose absorption and metabolism and the associated fluid transfer of the small intestine of rats was measured in vitro using an everted sac technique after daily doses of 0, 5, 25 or 225 infective larvae of Nippostrongylus for periods of one to five weeks. Though there were occasional significant changes in the physiology of the intestine there were no obvious patterns or trends with respect to time at any infection level. This differs from the response after a single infection. The possible role of immune adaptation and reduced immunogenicity of the worms during repeated infections is considered.

A Sudanese isolate of Schistosoma bovis from experimentally infected sheep was found to be highly pathogenic to albino mice. Eggs were first found in the livers 42 days after exposure. The distribution of eggs in the liver and small and large intestines changed little during the course of infection. Results arc compared with others using an Iranian isolate of S. bovis, which causes only a mild infection, and S. mattheci.