The purpose of this work has been to identify and describe the immature forms of those species of tachinids which have occurred as parasites of Pierisrapae and P. brassicae at the Imperial College Field Station, Slough, Bucks.

The influence of temperature and salinity on miracidial longevity and miracidial infectivity of the digenean, Himasthla militaris, has been examined. At 14, 25 and 30 °C the half-life of the miracidia was 1200, 630 and 420 min respectively, and infection of the first intermediate host, Hydrobia ventrosa, only occurred at 25 and 30 °C, for both temperatures 52% became infected. In the range 2·1 to 34‰ (2·1, 4·2, 8·5, 17 and 34‰) the miracidia had a minimal and maximal half-life of 60 and 630 min in water with a salinity of 2·1 and 17‰ respectively, while the infection of the snail host was possible only in water with a salinity of 8·5 and 17‰.

Arthur & Chaudhuri (1965) have reviewed the literature dealing with the taxonomic status of Nosomma monstrosum (Nuttall & Warburton, 1908). They have also redescribed the adults and have given the host and geographical distribution of this species. There have, however, been no descriptions or records of immature stages of this species. They are described and illustrated here from laboratory-reared and field-collected material. The parent females of the laboratory-reared material were compared with the female specimen in the Indian Museum collection, reg. no. 2172/17, on which the description of the female was based (Warburton, 1918).

Most sylvatic species of Trichinella are known to have poor infectivity to rats, but in the present study oral administration of bile from other hosts appeared to modify this infectivity. A total of 75 rats were inoculated in groups of 25 with 3 species of Trichinella (T. spiralis, T. nativa, and T. nelsoni) and each group of rats was given per os daily doses of bile from pig, sheep, chicken and fox respectively (4×5 rats). As a control 1 group of 5 rats was given daily doses of water. Whereas, the addition of bile did not increase the establishment of T. spiralis, fox bile had a significant positive effect on the establishment of muscle larvae of T. nativa and T. nelsoni. Addition of bile to cultures of the same Trichinella species had an overall negative effect on the in vitro survival of larvae. The present observation that carnivore bile favours the establishment of sylvatic Trichinella may explain why carnivores are equally receptive to all Trichinella species.

The interaction between host and infecting organism plays an important role in the survival of both of these components. The mechanisms whereby survival of one, or both, is achieved can be considered at various anatomical levels and degrees of complexity; those involving whole tissues together with events occurring at the cellular and subcellular levels. The involvement of sequestration, or the ‘standing apart’ of an invading organism from the host, as a mechanism of survival can also be examined at these various levels.

In April 1950, numerous ticks of the genus Ornithodoros were found in two coral caves, several hundred yards from the sea, near Diani about 20 miles south of Mombasa. Most of the ticks were found in the larger cave, which was irregular in shape, about 42 ft. long, and from 2 to 7 ft. high. Some of the ticks were crawling on the fine brown earth which covered the floors and others were just below the surface; none were seen on the walls.

The administration of an antihistomonal drug, dimetridazole, at a dose of 0·08% in feed, controlled experimental infections with Histomonas meleagridis in chickens. The treated birds developed no lesions and the duration of infection with H. meleagridis was reduced. This drug regimen, however, did not always prevent incorporation of H. meleagridis into eggs of Heterakis gallinarum; heterakid eggs pooled from medicated chickens in which H. meleagridis had never been detected transmitted the protozoan to 1 of 10 turkeys fed the eggs. Thus, therapeutic treatment of chickens with dimetridazole may reduce, but not eliminate, transmission of H. meleagridis by eggs of H. gallinarum from medicated birds.

The following note is published by way of supplement to the foregoing paper on “Tick Paralysis” by Hadwen, as it records a positive experiment carried out in Cambridge upon a dog experimentally infested with Dermacentor venustus obtained from Canada.

Hepatojarakus bandicoti sp.nov. has been described from Bandicota bengalensis (type host), Millardia meltada, Tatera indica and Mus musculus bactrianus. The genus Hepatojarakus Yeh, 1955, has been retained in the family Trichostrongylidae Leiper, 1912. This is the second record of Hepatojarakus and the first from India.

The material used for the following description consisted of three worms obtained from the intestine of the oystercatcher, Haematopus ostralegus occidentalis Neumann, shot near Aberystwyth. This is the first record of a protogynous tapeworm from Britain. In the whole of the Cestoda the protogynous condition is known only in four other genera, namely, Progynotaenia Fuhrmann (1909), with six species, and Proterogynotaenia Fuhrmann (1911), Leptotaenia Cohn (1901) and Gynandrotaenia Fuhrmann (1936, 1936a), each with a single species. The six known species of the genus Progynotaenia have been recorded from Egypt and the White Nile, Proterogynotaenia rouxi Fuhrmann from the Aru Islands off the coast of New Guinea, Leptotaenia ischnorhyncha (Lühe) from the Mediterranean and Gynandrotaenia stammeri Fuhrmann from Germany.

Juvenile female Litomosoides sigmodontis secrete a protein (Juv-p120) highly modified with dimethylethanolamine (DMAE). In an attempt to establish the source of this decoration worms were pulsed with [3H]-choline and [3H]-ethanolamine and the radio-isotope labelled products analysed. Both isotope labels were successfully taken up by the worms, as demonstrated by labelling of phospholipids with [3H]-choline, being predominantly incorporated into phosphatidylcholine and [3H]-ethanolamine into phosphatidylethanolamine. Isotope labelling of phosphatidylethanolamine was particularly striking with the worms taking up ~30 times as much labelled ethanolamine as choline. It was possible to detect faint labelling of Juv-p120 with [3H]-ethanolamine after prolonged exposure periods but, unlike the situation with the phospholipids, it was much more readily labelled with [3H]-choline. When pulsing with [3H]-ethanolamine it was also possible to detect isotope-labelled phosphatidylcholine, which may ultimately account for the low levels of labelling of Juv-p120. Overall our results raise the previously unconsidered but intriguing possibility that in L. sigmodontis, choline may be the precursor of DMAE.

Amputation experiments upon immature stages of Argas persicus (Oken 1818), Amblyomma hebraeum Koch 1844, and Hyalomma aegyptium (Linnaeus 1746) show that the mouthparts and legs of these ticks may be more or less regenerated when mutilated shortly after the ticks have abandoned the host in a fully engorged condition.

Haemozoin is a by-product of haemoglobin digestion by intraerythrocytic malaria parasites, which induces immunologic responses on different tissues, including endothelial cells. In the present paper, the incubation of human microvascular endothelial cells with haemozoin significantly inhibited MTT reduction, a measure of cytotoxicity, without increasing the release of cytoplasmic lactate dehydrogenase. Moreover, haemozoin did not induce apoptosis or cell cycle arrest nor decreased the number of live cells, suggesting that cells viability itself was not affected and that the inhibition of MTT reduction was only apparent and probably due to accelerated MTT-formazan exocytosis. After 30 min of MTT addition, a significant increase in the % of cells exocytosing MTT formazan crystals was observed in haemozoin-treated cells compared with control cells. Such an effect was partially reversed by the addition of genistein, an inhibitor of MTT-formazan exocytosis. The rapid release of CXCL-8, a preformed chemokine contained in Weibel–Palade bodies, confirmed that haemozoin induces a perturbation of the intracellular endothelial trafficking, including the exocytosis of MTT-formazan containing vesicles. The haem moiety of haemozoin is responsible for the observed effect. Moreover, this work underlines that MTT assay should not be used to measure cytotoxicity induced by haemozoin and other methods should be preferred.

A hypothesis to explain some features of Ascaris flexures is given. It is based on the co-operation of muscle cells in domains which may assume two states. In one state the muscles are long and it is mainly the non-contractile parallel elements that are in tension. The other state has short muscles exerting tension mainly in the contractile elements. The living animal changes shape if new domains are formed or if domain boundaries move. The hypothesis is applied to laboratory experiments and observations.

A range of monoclonal antibodies specific for Plasmodium falciparum were tested in vitro for their abilities to inhibit the multiplication of a partially synchronized culture of P. falciparum, to augment the phagocytosis of the parasites by macrophages, and to enhance the killing of parasites by peritoneal cells depleted of adherent cells. Seven of 17 monoclonal antibodies, ranging from culture supernatant fluid and ascitic fluid to purified IgG, showed dose- and time-dependent inhibition of parasite growth in vitro. At a concentration of 0·6 mg/ml, the inhibitory capacity of these monoclonal IgGs was above 94% over a 3-day culture period, much higher than that of the relevant polyclonal IgG. Four of 6 monoclonal antibodies tested augmented the phagocytosis of the parasites by macrophages, which occurred as a result of opsonization of the parasites. Four of 7 monoclonal antibodies examined showed cytotoxic activity on malaria parasites. Peritoneal cells depleted of adherent cells were capable of killing the parasites in the presence of monoclonal antibodies. These results indicate that there may be ‘monofunction’, ‘bifunction’, and ‘multifunction’ types of monoclonal antibodies against P. falciparum. The putative protective antigen of malaria parasites purified by ‘multifunctional monoclonal antibody’ affinity chromatography may have potential interest as a vaccine against the parasite or as an immunodiagnostic reagent for human malaria.

This investigation was commenced by one of us (J. A. I.) in 1910 and carried on for three and a half years. Our purpose was to determine as accurately as possible the percentage of appendices operated on for appendicitis which contained intestinal parasites. The results of a study of 100 unselected cases are given below.

Copepods belonging to the genus Lamippe live in the gastrovascular cavity of several alcyonarian genera. Eighteen species of these copepods are known (Zulueta, 1911), nineteen if the variety L. rubra decolor Zulueta 1908 is raised to species rank as suggested by Heegaard (1949). Each species is highly preferential in its choice of a host. Only one species is known to parasitize more than a single species of coelenterate, namely L. rubicunda (Olsson, 1869) which lives in two species of Alcyonium.