1. A parasitic spiral organism averaging 4 to 8μ long, with regular, closely set spirals about 0·75μ broad, has been found in the stomach in eight cats, none of which showed any obvious signs of gastric disturbance. The organisms occurred in the lumina of ducts and glands throughout the stomach, and also within the oxyntic cells. They were not seen in any part of the intestines except the very beginning of the duodenum, or in any other organ.

2. They are extremely active, and are readily stained by aniline dyes.

3. The mode of passage from one animal to another is not known, but food and faeces may be eliminated as possible sources of infection.

The results are described of a study of the distribution of the antigens in F. hepatica at various stages of development, and in the liver and spleen of experimentally infected rats using globulins labelled with fluorescein isothiocyanate, from rats and sheep infected with F. hepatica.

Possible uses of this technique in aiding the diagnosis of fascioliasis are indicated.

I wish to thank Dr A. W. J. Broome for a supply of the metacercariae of F. hepatica, and Dr J. S. S. Lowe who kindly isolated and labelled the globulins with fluorescein isothiocyanate. Miss Enid Eccleston gave valuable technical assistance.

Nine vervet monkeys and nine baboons were infected with eggs of Echinococcus granulosus per as. Six of the vervets and one of the baboons possessed hydatid cysts at autopsy, 15–28 months post-infection. The sequential IgG response to hydatid fluid and protoscolex antigens showed considerable inter-animal variation. Infected vervets and baboons became seropositive after an average of 8 months post-infection. Considerable fluctuation in the IgG response was observed, particularly to the hydatid fluid antigen which, in humans, may contribute to the existence of a significant proportion of seronegative individuals. Vervets, in particular, may be useful to study immunological events associated with exposure, development and resolution of hydatid disease in outbred human populations.

In this in vitro study we investigated whether previously described in vivo plasma-associated effects, that occurred in the period shortly after penetration of Trichobilharzia ocellata into the snail host Lymnaea stagnalis (1.5–72 h post-exposure; p.e.) were direct and/or indirect effects of parasite-derived factor(s). It was investigated whether the effect is mediated by the central nervous system (CNS) of the host. Phagocytic activity of the haemocytes was taken as a parameter for the activity of internal defence of the host. A number of preliminary experiments were performed. When the supernatant of in vitro cultured parasites (33 h; corresponding with their developmental stage in vivo when plasma-associated activation was found) was applied directly to monolayers of haemocytes, it appeared to enhance their phagocytic activity. No direct effect, however, was found with a supernatant of parasites cultured for a longer period of time (72 h; when, in vivo, a plasma-associated suppression was found). In this case, indirect suppression was detected: the parasites appeared to have released a factor that induced the CNS of the host to release material suppressing the activity of the internal defence system of the host. To date the nature of this factor is unknown.

A description is given of a Babesia-like parasite found in the erythrocytes of two Cercopithecus pygerythrus monkeys probably from East Africa. Morphologically it seems identical with a parasite found by Mayer (1934) in Macaca irus monkeys from Java and named by him Entopolypoides macaci. On the other hand, the present African type differs from the Javan one in that it does not readily infect M. irus or M. mulatta monkeys; and it might well be named provisionally E. macaci (cercopitheci).Morphologically, the early forms are fine rings with a large vacuole but the more mature parasites form several fine long processes which are best seen under phase-contrast illumination. The cycle in the erythrocytes probably ends by division into four new parasites and it takes 3 days to quadruple the number. There is no synchronicity, such as occurs with malaria.The parasite was passed by syringe into Erythrocebus patas, Papio papio and Cercocebus galeritus monkeys in which it produced a light parasitaemia if they were intact, or an intense one (up to 70% erythrocytes parasited) if they were splenectomized. In both cases the bouts of parasitaemia are prolonged for weeks, and they may continue with relapses apparently for years. A light transient infection was produced in one splenectomized Macaca mulatta and in one out of two intact M. irus monkeys, but not in one M. arctoides (splenectomized), one Cebus albifrons, one C. apella, two Aotus trivirgatus and two Pan troglodytes (one splenectomized). Apparently the parasite readily infected African lower primates, hardly infected Asiatic ones, and did not infect American ones.Even in susceptible splenectomized monkeys, in which it produced prolonged intense parasitaemia, the parasite causes little pathogenic effect beyond a moderate anaemia.Attempts were made to transmit it through Rhipicephalus sanguineus, Dermacentor andersoni, Ornithodoros (sp.), Ornithonyssus bacoti and Aedes aegypti but they were unsuccessful. Probably the vector is an Ixodid tick.Chemotherapeutically the parasite was sensitive to a babesicidal compound, Imidocarb (3,3′-bis-(2 imidazolin-2yl) carbanilide) and to primaquine but not to chloroquine, pyrimethamine, pentamidine, Berenil or homidium.

Recent studies on the motility of coccidian sporozoites have demonstrated a membrane-associated contractile system capable of moving certain intramembraneous components down the parasite surface propelling it forwards. The properties of this system resemble recorded observations on host cell invasion. In this study the invasive behaviour of Eimeria tenella and E. acervulina has been examined, with reference to the above findings, by light microscope and scanning and transmission electron microscopes. Known inhibitors of motility prevent invasion, though attachment appears unaffected. Invasion itself consists of 3 phases; attachment and orientation, induction of a parasitophorous vacuole and translocation of the parasite into the vacuole. Ultrastructural examination reveals a close membrane/membrane association maintained throughout invasion. From these results it is suggested that the parasite enters the parasitophorous vacuole by ‘capping’ the host/parasite junction down its body, so locomoting into the host cell. Such a model has two main advantages; it requires no additional modifications to either cell, and the specificity of membrane receptors would enable the one membrane-associated contractile system to be responsible for locomotion, antibody capping and host cell invasion.

Whilst engaged on protozoological investigations of dysentery and allied diseases in Mesopotamia I had the opportunity of examining the stools of a large number of hospital patients, both British and Indian, and of noting the presence of worm ova as well as protozoan parasites.

The population dynamics of Sphaerospora dicentrarchi and S. testicularis, myxosporean parasites of sea bass (Dicentrarchus labrax), was studied in different groups of cultured and wild fish. S. dicentrarchi prevalence was higher for wild fish (100%) than for cultured ones (70.5%). Infection levels increased with host age and there were no significant sex differences in cultured fish. Among parasitized organs, the gall bladder and intestine registered the highest infection levels in wild and cultured fish. A progressive increase in infection levels of S. testicularis was observed in cultured males during the spawning season in four consecutive periods. The evolution of the percentage of the different parasitic stages is pointed out. The infection seems to be related to water temperature and gonadal maturation.

Glycoproteins of Trypanosoma congolense have been detected on SDS-polyacrylamide gels using the Concanavalin A peroxidase technique. Using [35S]diazoniobenzenesulphonate as a marker for cell surface proteins it was possible to distinguish between internal glycoproteins and the surface coat proteins. On SDS-polyacrylamide gels Con A reacted with the surface coat proteins. Results obtained from Con A-induced agglutination of living trypanosomes indicated that sugars of the surface coat proteins were accessible to Con A. This was reinforced by the cytochemical visualization of Con A binding to the trypanosome surface. The results suggested that the surface coat protein contained α-linked d-mannosyl, d-glucosyl, or N-acetyl-d-glucosaminoyl residues, which are exposed exteriorly on the surface coat.

[This paper is the final report on the Diptera collected by the Percy Sladen Trust Expedition under Professor J. Stanley Gardiner, F.R.S., in the Seychelles and other islands of the Western Indian Ocean in 1905 and 1908–9. Many reports on the insects collected have appeared in the special series of volumes devoted to that Expedition, Tr. Linn. Soc.London, ser. 2 (Zool.), xii–xviii (from 1907 onwards), but it has not been possible to include all the entomological contributions in that series. I am greatly indebted to the Editor of Parasitology for accepting the present work, which was offered for publication in this journal as it deals with a number of parasitic forms—Bombyliidae, Sarcophaginae, Tachininae, etc. A list of all the other reports on Diptera collected by this Expedition, with full references, is given in Ent. Monthly Mag., 58, 1922, p. 184.

Polymerase chain reaction (PCR) combined with non-radioactive DNA hybridization was applied for the detection and characterization of a 150 bp tandem repeat of Onchocerca volvulus. DNA of worms from western Uganda was amplified and then probed with a digoxygenin-labelled oligonucleotide, specific for the forest form of O. volvulus and compared to samples from various African countries. Hybridization was only observed with PCR products from the forest in Liberia, south-eastern Ghana, Benin and southern Cameroon, but not with worms from Uganda or the savannah in Burkina Faso and northern Ghana. A nested PCR using primers derived form the forest form-specific DNA sequence confirmed these results. Morphometric studies revealed length differences between the microfilariae of Ugandan O. volvulus to those of West Africa, especially to those of the savannah in Burkina Faso. It is concluded that the forest/savannah classification of O. volvulus from West Africa is not suitable for Simulium weasel-transmitted O. volvulus from Uganda.

It was observed that uninfected red cells resuspended in supernatant from Plasmodium falciparum cultures, then examined between a glass slide and cover-slip, assumed varying morphologies. A series of experiments suggested that P. falciparum releases molecules which cause red cells to become stomatocytic (cupped). These molecules, some of which are heat- stable, have an apparent molecular weight < 12 kDa, are released at or about schizogony, and do not bind tightly to erythrocytes.

The in vivo effects of the anthelmintics taenifugin, VÚFB 14170 and VÚFB 15269 on the tegument of Hymenolepis fraterna have been examined by SEM, TEM and cytochemistry. The drugs were given to H. fraterna-infected mice on the 14th day post-infection in a single oral dose of 150, 200 and 200 mg/kg, respectively. By 72 h post-treatment, the drug-induced pathomorphological changes in the tegument indicated that all three drugs had a significant effect. Changes were most pronounced on the brush border and in the intercellular material. On the apical surface, there was blebbing as well as accumulation of membrane fragments over the microthrix tips and erosion of the brush border. The intercellular material was changed in structure, showing increased electron density in some areas and oedema of the intercellular spaces in other areas. There were also fractures of the tegument of variable depth, sometimes reaching to the parenchyma. These results suggest altered tegumental integrity and, occasionally, complete disruption of the selective permeability barrier created by the normal tegument. This suggestion is further supported by the penetration of ruthenium red into some tegumental areas and its distribution into the intercellular spaces, down to the parenchyma. The intrategumental lysosomes also appeared to be significantly activated. There was evidence of autophagy in both distal cytoplasm and tegumental cells. Mature and gravid proglottides were more susceptible to drug damage than those in the anterior strobila and neck.

1. The exrectory system of Anoplocephala perfoliata has been re-described and shown to consist of a dorsal ‘network’ system of vessels to which the flame cells are connected and a ventral pair of longitudinal vessels linked only by a transverse vessel in each proglottid.

2. The two excretory systems unite only in the apical ramifying vessels of the scolex.

3. Alkaline phosphatase activity was demonstrated in the cuticular microvilli, the subcuticular region and in the excretory vessels.

4. Non-specific esterase, insensitive to 10−4m E 600, was located in the lappets and embryonated eggs and esterases, inhibited by 10−4m E600, in parts of the cuticle and subcuticular region and parenchyma.

5. Cholinesterases were found in the nervous system and in the reproductive ducts.

6. Aminopeptidase was found in the neck region, in the undifferentiated proglottids, the active testes and ovaries, the male reproductive ducts and in the region of high metabolic activity in the fringe of the proglottid.

The effects of changes in red cell membrane properties on invasion by Plasmodium falciparum have been studied by varying the cholesterol content and the intracellular concentration of polyamines. Increased cholesterol content is known to cause large reductions in the internal fluidity of the phospholipid bilayer and a change in its preferred direction of bending, but does not cause changes in gross mechanical rigidity. Polyamines, on the other hand, are thought to increase the cohesion of the membrane cytoskeleton and impede translational diffusion of transmembrane particles, as well as increase trie mechanical rigidity of the membrane. Cells with membranes augmented by 50% in cholesterol show no reduction in their susceptibility to parasitic invasion, whereas an increase in cytosolic polyamine (especially spermine) concentration leads to strong inhibition of invasion. In neither case is the development of the intracellular parasite affected. We conclude that it is the macroscopic, rather than the microscopic rheoelastic properties of the membrane that influence the invasion process. Depletion of membrane cholesterol leads to a substantial reduction in parasitaemia; it is suggested that this is linked to the reduced phosphorus incorporation into spectrin in these cells. Polyamines may exert a significant effect at physiological concentrations and the possibility must be considered that the elevated polyamine levels found in red cells in sickle cell disease may account for the protection against P. falciparum.

A list is given of all habroneme species recorded from Australian birds, as well as a key to all known genera of Habronematinae. New species described are: Cyrnea (Procyrnea) dollfusi from Ninox novaeseelandiae; Cyrnea (Procyrnea) falco from Falco longipennis and F. berigora; Cyrnea (Procyrnea) spiralis from Philemon argenticeps, Entomyzon cyanotis, Oriolus sagittatus and Lalage sueuriitricolor; Excisa biloba from Podargus strigoides, Ninox novaeseelandia; Viguiera longicollis from Colluricinda rufiventris, C. harmonica, Anthochaera carunculata and Microeca fascinans; V. chibiae from Chibia bracteata; V. chabaudi from Podargus strigoides. Partial redescriptions are given of Cyrnea (Procyrnea) paraleptoptera (Johnson & Mawson) from the type specimens; Cyrnea (Procyrnea) mansioni from Falco berigora, Haliastur sphenurus, Astur novaehollandiae, and a ‘hawk’; Cyrnea (Procyrnea) sp. from a parrot, Psephotus haematonotus; Hadjelia truncata from Eurystomus orientalis; Hadjelia acuariana (s. Stellabronema acuariana Gushans-kaya) from Podargus strigoides; Torquatella balanocephala from Merops ornatus, and Torquatella sp. from Centropus phasianus.

Sarcoptic scabies in man and in domestic and wild mammals has engaged the attention of a large number of investigators since its true nature was finally established about the year 1835. The subject has been approached from the medical, the veterinary and the entomological side, and the literature concerning it has attained very large dimensions. Nevertheless it cannot be said that our knowledge of the matter is in a satisfactory condition, since no two writers agree entirely in their accounts of the morphology and bionomics of the human itch-mite, and the most diverse views are held as to the inter-relation of the forms which infest man and the lower animals.