Some time ago I received for identification a microscopic preparation of parasites taken, on 11 March 1929, from a flying squirrel (Sciuropterus volans L.) in the neighbourhood of Agraz, Tartar Republic. The preparation mounted in Canada balsam contained one male and two females. Later I examined a rather large collection of flying squirrels in the Division of Mammals of the Zoological Institute of the Academy of Sciences of U.S.S.R. In one jar containing a flying squirrel from Verchoijansk, Yakutia, 67° 33′ N, 133° 51′ E, I found, among the debris on the bottom, a single specimen of the same parasite.

When incubated in vitro for 24 h, oncospheres of Hymenolepis diminuta absorb and metabolize radioactive glucose. Between 0 and 12 h post-activation, oncospheres absorb glucose, but glucose is neither metabolized into other carbohydrates nor incorporated into the ethanol-precipitable fraction (which would contain glycogen). Between 12 and 24 h post-activation glucose is incorporated into a number of higher molecular weight carbohydrates that are demonstrable in ethanol extracts of the larvae, as well as the incubation media. Furthermore, measurable amounts of radioactivity are incorporated into the ethanol-precipitable carbohydrate fraction of oncospheres. To determine if these temporal changes in carbohydrate metabolism occurred spontaneously following activation, oncospheres were pre-incubated for 12 h (0–12 h post-activation) in the absence or presence of glucose, and then transferred to media containing radioactive glucose for an additional 12 h (12–24 h post-activation). In these latter experiments, glucose absorption and metabolism between 12 and 24 h post-activation were virtually identical to glucose metabolism in oncospheres that were incubated in radioactive glucose for 0–12 h immediately following activation. Thus, these data do not support the hypothesis that the temporal shift in carbohydrate metabolism occurs spontaneously.

Claparède (1869) established the genus Myocoptes for a mite, found upon a house-mouse (Mus musculus musculus L., 1758), which had been described by C. L. Koch (1844) under the name Sarcoptes musculinus (syn. Listrophorus larisi Vorobiov, 1938). In this genus sexual dimorphism is pronounced; the female has legs iii and iv modified and provided with processes with which it can maintain a firm grasp on the fur of its host. In the male this modification is only present on legs iii.

Cortisone appears to enhance the production of some humoral agent in the serum of infected mice which, when injected in extremely small quantities into experimental, infected animals, produces a decrease in the parasitaemia in the peripheral blood. This effect is not produced by clean serum, and only slightly, if at all, by the serum from infected mice which have received no cortisone.

While fixing a number of tapeworms (Anoplocephala perfoliata Goeze) from the small intestine of the horse, I came across a small tri-radiate specimen. This abnormality has previously been described by Neumann (2), but only briefly, and without any account of the internal anatomy. It therefore seemed advisable to compile a short account of the most salient characteristics. For the material I am indebted to Dr C. L. Boulenger, Helminthologist of this Department. I have also to thank Professor L. G. Neumann for obtaining for me a copy of his paper.

LA litérature ne nous offre que des renseignements fort embrouillés sur les Acanthocéphales parasites intestinaux de l'eider (Somateria mollissima L.).Ces parasites furent decouverts par Phipps en 1774–1775 et décrits par lui sous le nom de Sipunculus lendix. Cependant, de la description et surtout des figures de cet auteur on voit bien qu'il ne s'agissait point de Sipunculides mais de vrais Acanthocéphales (Lühe, 1905). Plus tard, d'autres auteurs ont rapporté cette espéce comme synonyme d'Echinorhynchus polymorphus Brems

The immune evasion gene family of malaria parasites encodes variant surface proteins that are expressed at the surface of infected erythrocytes and help the parasite in evading the host immune response by means of antigenic variation. The identification of Plasmodium vivax vir orthologous immune evasion gene family from primate malaria parasites would provide new insight into the evolution of virulence and pathogenesis. Three vir subfamilies viz. vir-B, vir-D and vir-G were successfully PCR amplified from primate malaria parasites, cloned and sequenced. DNA sequence analysis confirmed orthologues of vir-D subfamily in Plasmodium cynomolgi, Plasmodium simium, Plasmodium simiovale and Plasmodium fieldi. The identified vir-D orthologues are 1–9 distinct members of the immune evasion gene family which have 68–83% sequence identity with vir-D and 71·2–98·5% sequence identity within the members identified from primate malaria parasites. The absence of other vir subfamilies among primate malaria parasites reflects the limitations in the experimental approach. This study clearly identified the presence of vir-D like sequences in four species of Plasmodium infecting primates that would be useful in understanding the evolution of virulence in malaria parasites.

Volume conducted potentials were recorded from schistosomula of Schistosoma mansoni transformed mechanically (MS) and by skin penetration (SS). The spontaneous electrical activity recorded consisted of bi and triphasic transients ranging from 20 to 200 μV in amplitude and 10 to 300 msec in duration. Low amplitude potentials occurred at a much greater frequency than large amplitude potentials, which appeared to correlate with peristaltic-like contractions of the schistosomulum's musculature. Electrical activity in the schistosomulum was highly sensitive to a number of agents believed to affect metabolic pathways, the neuromuscular system or the host/parasite interface of adult schistosomes. Among the most reactive substances were potassium antimony tartrate, eserine, poly-L-arginine and potassium cyanide. Over a wide range of experimental treatments, electrophysiological responses in schistosomula transformed from cercariae by mechanical decaudation and skin penetration were remarkably similar, supporting the notion that MS are suitable material for in vitro immunochemical, biochemical and physiological study. Some treatments, however, were more or less effective in altering electrophysiological activity and motility in the schistosomulum than in adult S. mansoni. This suggests that significant physiological alterations may occur during development from skin stage to adult parasites concomitant with immunochemical and morphological changes already known to occur.

Using foot-pad infection of female C57BL/6, DBA/2J and NMRI-IVIC mice as an animal model for American cutaneous leishmaniasis (ACL), we evaluated the inhibitory effect of Formycin B (FoB) on the infection produced by 7 different Leishmania isolates. When treatment was initiated some days, or even some weeks, after infection a significant leishmanistatic effect was detected on mice infected with all Leishmania isolates, which reached 30–55 weeks for some isolates. The optimal dose schedule was 1·25 mg/kg body weight/day, injected intraperitoneally for 20 consecutive days. Significant differences in the sensitivity of various Leishmania spp. to FoB were found, either in vivo, or in vitro where a high [3H]FoB incorporation rate was found only for certain Leishmania isolates. The low toxicity of this drug and the sensitivity of the 7 Leishmania isolates tested suggest that FoB could be useful in the treatment of ACL.

Glycosidase activities in the adults and juveniles of the lung fluke Paragonimus ohirai and P. westermani adults were demonstrated histo-chemically. For comparative studies, histochemical examination was also made on the adults of the liver fluke Fasciola hepatica. The enzymes examined were N-acetyl-β-glucosaminidase (EC 3.2.1.30), β-glucuronidase (EC 3.2.1.31), β-galactosidase (EC 3.2.1.23), α-glucosidase (EC 3. 2. 1. 20) and β-glucosidase (EC 3.2.1. 21). The distribution of β-glucosaminidase was similar in juveniles and adults. Strong reaction sites for the enzyme were the caecal brush border, tegument, sub-tegumental cells and testes. In contrast, no staining reaction occurred in the caeca of F. hepatica, although the tegument and parenchymal cells were weakly stained, β-glucuronidase activity was associated only with the luminal surface of the caeca in the juveniles. However, luminal contents also appeared stained and this might suggest that the activity in the caeca is not endogenous. β-galactosidase was localized in the caeca, sub-tegumental cells and tegument in both juveniles and adults. No reaction occurred for the other two enzymes, α- and β-glucosidase.

Im Jahre 1908 haben wir auf dem IX. Internationalen Tierärztlichen Kongresse im Haag einen Bericht über die Piroplasmose der Pferde und Esel in Transkaukasien erstattet und etwas später eine kurze Bemerkung darüber in russischer Sprache publiziert. Nachher haben wir aber noch einige Fälle von Piroplasmose bei den Pferden beobachtet, wobei wir die Ansicht Nuttall's bestätigen konnten über die Existenz zweier selbstständiger Arten der Pferdepiroplasmose, welche durch zwei besondere Arten von Blutparasiten der Gattung Nuttallia und Piroplasma verursacht werden.

Since the discovery of the parasite Kala Azar by Lt.-Col. Leishman, R.A.M.C., a number of investigators have endeavoured to reproduce the disease in the lower animals but without success. The recent discovery of Nicolle that dogs are susceptible to an allied human parasite (Herpetomonas infantum) has added a fresh stimulus to work along these lines, and in order to see whether the dog can be infected with H. donovani I carried out some inovulation experiments, which I propose recording in this paper.

This study assessed the role of historical processes on the geographic isolation, molecular evolution, and morphological diversification of host-parasite populations from the southern Brazilian coast. Adult specimens of Scleromystax barbatus and Scleromystax macropterus were collected from the sub-basin of the Nhundiaquara River and the sub-basin of the Paranaguá Bay, state of Paraná, Brazil. Four species of Gyrodactylus were recovered from the body surface of both host species. Morphometric analysis of Gyrodactylus spp. and Scleromystax spp. indicated that subpopulations of parasites and hosts could be distinguished from different sub-basins and locations, but the degree of morphological differentiation seems to be little related to geographic distance between subpopulations. Phylogenetic relationships based on DNA sequences of Gyrodactylus spp. and Scleromystax spp. allowed distinguishing lineages of parasites and hosts from different sub-basins. However, the level of genetic structuring of parasites was higher in comparison to host species. Evidence of positive selection in mtDNA sequences is likely associated with local adaptation of lineages of parasites and hosts. A historical demographic analysis revealed that populations of Gyrodactylus and Scleromystax have expanded in the last 250 000 years. The genetic variation of parasites and hosts is consistent with population-specific selection, population expansions, and recent evolutionary co-divergence.

Three coccidian parasites were found in California Banded King Snakes, Lampropeltis getulus californiae: Isospora crotali, an intestinal Eimeria, and a haemogregarine. Schizogonous stages of the latter occurred predominantly in liver, and were remarkably similar to those described for other blood Coccidia.

Dr Charles E. Shaw of the San Diego Zoological Society identified the snakes, and Dr Gordon Ball, Professor of Zoology at the University of California, Los Angeles, kindly reviewed the manuscript.

A preliminary report on the results of our studies on the comparative efficacy of different culicifuges under laboratory conditions has been published (Roy, Ghosh & Chopra, 1942).

Experiments were conducted in guinea-pigs to elucidate the parameters affecting the development of protective immunity against Schistosoma japonicum induced by a cryopreserved, irradiated schistosomula vaccine such as the number of immunizations, route of injection and the use of adjuvants. Results obtained indicated that the cryopreserved, irradiated schistosomula vaccine was effective by either intradermal or intramuscular injection. One intradermal injection with BCG adjuvant resulted in an average worm reduction of 50·24%, only a little lower than that of a non-cryopreserved, irradiated vaccine, 53·55%, with no statistically significant difference between the two. By intramuscular injection the worm reduction was lower (max. 40%) whether given with or without adjuvants or in 1 or 2 injections.

The species described in this paper were found in Bithynia tentaculata from the Wentloog level, near Cardiff, South Wales. The larval stages of Psilotrema oligoon are redescribed and the taxonomy of the adults discussed. C. frondicola sp.nov. is a psilostome cercaria which has the probable flame-cell formula 2 [4 + 4 + 4 + 4 + 3 + 3] = 44. It emerges at night or during early morning, is positively phototactic and will not normally encyst on anything but vegetation. C. granocutis sp.nov. is also a psilostome cercaria; it is very small and has the probable flame-cell formula 2 [3 + 3 + 3 + 3 + 3] = 30. It emerges during the afternoon and will encyst freely on a variety of substrata.

I thank Professor J. Brough of the Zoology Department, Cardiff, for the facilities provided, Dr D. A. Erasmus for supervising and encouraging this work and Dr S. M. Willmott, Director of the Commonwealth Bureau of Helminthology, for providing library facilities. This study was carried out during the tenure of a D.S.I.R. research studentship.

Leishmania mutants have contributed greatly to extend our knowledge of this parasite's biology. Here we report the use of the mariner in vitro transposition system as a source of reagents for shuttle mutagenesis and targeted disruption of Leishmania genes. The locus-specific integration was achieved by the disruption of the subtelomeric gene encoding a DNA-directed RNA polymerase III subunit (RPC2). Further inactivation of RPC2 alleles required the complementation of the intact gene, which was transfected in an episomal context. However, attempts to generate a RPC2 chromosomal null mutant resulted in genomic rearrangements that maintained copies of the intact locus in the genome. The maintenance of the RPC2 chromosomal locus in complemented mutants was not mediated by an increase in the number of copies and did not involve chromosomal translocations, which are the typical characteristics of the genomic plasticity of this parasite. Unlike the endogenous locus, the selectable marker used to disrupt RPC2 did not display a tendency to remain in its chromosomal location but was targeted into supernumerary episomal molecules.