A new coccidian parasite, Caryospora dendrelaphis sp.nov., with endogenous stages in the duodenal epithelium is described from the Australian colubrid snake Dendrelaphis punctulatus (Gray).

A flagellate from Polietes lardaria, closely allied to Herpetomonas muscarum, has been repeatedly isolated in bacteria-free culture by the use of quinanil after numerous attempts to isolate it by other methods with one exception had failed. The flagellates were exposed to 1/10,000 or 1/100,000 quinanil for 2–4 or more hours and cultivated in Locke serum agar, the medium for the first subculture containing quinanil in concentrations of 1/10,000 or 1/50,000. The proofs of the purity of the cultures were exhaustive.

We are greatly indebted to Dr St John-Brooks and the National Collection of Type Cultures for certain of the flagellates isolated by Noguchi and Tilden. One of us (F. C. H.) has also been in receipt of grants from the Medical Research Council, and he would like to take this opportunity of expressing his thanks to that body.

A major issue for the proper understanding of the evolution of life-cycle histories is the regulation of voltinism and its variation. Diapause characteristics are known to regulate voltinism, but the underlying mechanisms are poorly understood. This paper studies diapause duration and voltinism variation in a haematophagous diptera parasitizing 2 sympatric hosts with very different breeding phenologies. We hypothesize that bivoltinism will be more frequent in carnid flies parasitizing an early breeding, multi-brooded species than in flies parasitizing a late breeder, single-brooded species. We obtained evidence of the co-occurrence of uni- and bivoltinism in both clutches of the multi-brooded Spotless starling (Sturnus unicolor) as well as in clutches of the single-brooded European roller (Coracias garrulus). Unexpectedly, the proportion of bivoltine flies was similar in both host species. A remarkable degree of host-parasite synchronization at the population level was found for bivoltine flies. Our findings reveal the facultative nature of diapause in Carnus. We discuss the influence of abiotic conditions and host availability on polymorphism in life-history cycles and the consequences both for the parasite and the host.

1. This paper reviews the morphology, distribution and hosts of I. schillingsi Neumann, 1901.

2. Two new species, I. rageaui from the Cameroons, and I. lemuris from Madagascar are described and figured. The latter shows obvious African affinities and is but slightly different from its African relative.

3. I. schillingsi is, with the exception of Lophiomys ibeanus (crested rat), known only from Colobus monkeys, I. rageaui from monkeys of the Cercopithecus group and I. lemuris from Lemur rufifrons.

A good deal of doubt still exists in many quarters as to the exact meaning of the term Leucocytozoon applied to certain Haematozoa. The term Leucocytozoaire was first used by Danilewsky in writing of certain parasites he had found in the blood of birds. In a later publication he uses the term Leucocytozoon for the same parasites though he does not employ it as a true generic title. In this latter sense it was first employed by Ziemann who named the parasite of an owl Leucocytozoon danilewskyi, thus establishing this parasite the type species of the new genus Leucocytozoon. It is perhaps hardly necessary to mention that Danilewsky and Ziemann both used this name because they considered the parasite in question to inhabit a leucocyte of the bird's blood. There has arisen some doubt as to the exact nature of this host-cell. Some authorities consider it to be a very much altered red blood corpuscle, some perhaps more correctly an immature red blood corpuscle, while others adhere to the original view of Danilewsky as to its leucocytic nature. It must be clearly borne in mind that the nature of the host-cell does not in any way affect the generic name Leucocytozoon. If it could be conclusively proved that the host-cell is in every case a red blood corpuscle the name Leucocytozoon would still remain as the generic title though it would have ceased to be descriptive.

Within the last decade problems dealing with life cycles and relationships of the Strigeid Trematodes have received considerable attention. Among the European workers Szidat (1929, 1929 a) has given the most complete summary of the anatomy, development and systematic position of the Strigeidae, while in North America La Rue (1926), his students and associates, have been contributing to our knowledge of the anatomy, relationships and life histories.

An account is given of the general structure of Proteocephalus pollanicola. The genital system is dealt with in greater detail. The characteristic features of the species are enumerated.

The male portion of the reproductive system consists of 60–75 testes in a single layer; vasa efferentia with a lining epithelium; a wide, coiled vas deferens; a small cirrus-sac; a coiled ejaculatory duct and a short cirrus. A description is given of the histological structure of the male ducts.

The vagina opens anterior to the cirrus-sac. A well-developed vaginal sphincter is present. The seminal canal communicates with the oviduct and the uterine canal. An oocapt is present; the transverse vitelline ducts and the ovary open into it. A few unicellular glands are present hi the vicinity of the oocapt; these possibly represent Mehlis's gland. An ootype is absent. The histological structure of the female ducts is described.

This study provides the first quantitative assessment of the cutaneous reaction elicited in naive and sensitized rats by invading larvae of Strongyloides ratti. Parasites were identified in skin samples harvested from both naive and sensitized rats between 0·5 and 8 h following percutaneous infection, but were no longer visible at the site of invasion at 24 h. Mast cells, neutrophils, eosinophils and mononuclear cells recruited into the dermis in response to invading larvae were recorded and quantified. Cellular infiltrates were observed as early as 1 h post-invasion in naive/challenged skin, where total cell numbers were up to 3 times greater than in naive control tissue. Peak numbers of all cell types were recorded from 3 to 8 h in both naive/challenged and sensitized/challenged hosts. Interestingly, the reaction in sensitized/challenged rats was neither enhanced nor accelerated, a feature perhaps attributable to lack of recognition of parasite antigens by the host. This possibility was investigated by immunofluorescent labelling, which clearly demonstrated changes in the surface antigen profile of the parasite following penetration of the host skin both in vitro and in vivo. It is proposed that these changes in surface antigenicity constitute an evasive stratagem used by the parasite to deter the host from mounting a potentially lethal inflammatory response.

Transaminase activity in homogenates of larval Digenea indicates that alanine aspartic acid, glutamic acid and their α-keto acid analogues could form an important link between carbohydrate and nitrogen metabolism. As few amino acids participate in transamination it is doubtful whether this process plays a major role in protein synthesis.

The level of free amino acids in Diclidophora merlangi is high, comprising over 500 μmoles/g ethanol extracted dry weight. A single amino acid, proline, constitutes some 70% of the total pool. Analysis of parasite protein and host blood and mucus revealed low proline levels, suggesting that the high free pool content was not related to a requirement for protein synthesis or to its abundance in the diet of the worm. Experiments revealed that proline was not involved specifically in osmoregulation, and the reasons for the large amounts present in Diclidophora remain unknown.

A new Coccidia species is reported from the natural population of Pied Flycatcher (Ficedula hypoleuca) in northern Germany. Sporulated oocysts were found in faeces from 6 of 8 sampled adults. The spherical oocysts of the new Isospora species have a brownish, smooth, bi-layered wall. Average size of sporulated oocysts was 19·4×19·3 μm (17·5–22·8 μm×17·5–22·8 μm) with a shape index (length/width) of 1·0. The sporulated oocysts have no micropyle or residuum, but enclose several small polar granules that often cluster into 2–3 dumbbell-shaped formations. Sporocysts are slightly elongated, rounded at the end opposite the Stieda body, 15·3 μm×9·2 μm in size (13·8–16·1 μm× 8·5–10·3 μm), and have a shape index of 1·7 (1·6–1·8). The Stieda body has a prominent knob-like cap, whereas the substieda body is absent. Sporocysts contain a small compact sporocyst residuum and 4 sporozoites. COI haplotypes identical to those isolated from faecal oocysts were PCR amplified from the blood of 13-day-old nestlings, suggesting that the newly described species has extra-intestinal stages in blood. This represents the first description of a new avian Isospora species supported by molecular sequence data from the same oocysts that are described morphologically.

The pathogenicity of Trichomonas species is well documented. Although their exact involvement in gum disease is not fully understood, recent studies suggest a correlation between these protozoa and periodontitis. This case report details the first chair-side observation in Europe of an oral trichomonad infection in a child with periodontitis, by direct microscopy. The dramatic recovery of the patient, observed following administration of an anti-parasitic treatment, confirms the necessity of further investigation in this field.

This paper reports the anti-cryptosporidial effects of, and concomitant amelioration of the histological changes in the gut of neonatal rats with intestinal cryptosporidiosis treated with the dinitroaniline, oryzalin. The ED50 was determined to be 7 mg/kg using twice daily doses administered for 3 consecutive days. A maximum inhibition of 85.5% was achieved at 25 mg/kg and this inhibition remained constant despite increasing the oryzalin dose to 200 mg/kg. Cryptosporidiosis significantly decreased the intestinal villus/crypt (VC) ratio by approximately 50% (duodenum = 2.3, jejunum = 2.5 and ileum = 1.7) when compared to uninfected untreated controls (duodenum = 4.3, jejunum = 5.9 and ileum = 4.5). Treatment with oryzalin doubled the VC ratio in the duodenum, jejunum and ileum following doses of 5 mg, 50 mg and 200 mg/kg respectively. Oryzalin concentrations in the small intestine contents and plasma were determined, using HPLC, at 0.5, 1 and 2 h after dosing. The much greater dose required to return VC ratios to normal in the ileum (200 mg/kg) compared to the duodenum (6.25 mg/kg) appeared to reflect the decreased concentration of the drug in the distal small intestine. Concentrations of oryzalin equivalent to the in vitro IC50 were maintained for 2 h in the first half of the small intestine following a single dose of 100 mg/kg.

The pathognomic, serologie and morphometric identity of a Babesia sp. recently isolated from sheep in Argyllshire was studied. Initially, problems were encountered due to the occurrence of Eperythrozoon ovis as a contaminant of the isolate and treatment with neoarsphenamine failed to remove it. Finally, a combination of oxytetracycline therapy and rapid passage allowed isolation of the Babesia sp. and its preservation in the form of a glycerolized, infected blood stabilate. Inoculation of the stabilate into splenectomized sheep produced a mild non-pyrogenic disease. Serologically the parasite was seen to have no affinity with either of the two Babesia recognized as parasitizing sheep, but some affinity with the cattle parasite B. divergens. Morphometrically it was seen to have affinity with the deer parasite B. capreoli and with the Babesia sp. isolated from red deer in Scotland, and the low number of budding forms of the parasite seen suggested that the parasite might be reproducing slowly in an alien host. It was concluded that the parasite was likely to be B. capreoli derived from red deer via the tick Ixodes ricinus.

Alexeieff (1911) described two trichomonads from the horse-leech Haemopis sanguisuga:Tetratrichomonas prowazeki and Trichomonas sanguisugae. T. prowazeki is characterised by its four anterior flagella of unequal length and its poorly developed axostyle. The feature which he considered to be of specific value in T. sanguisugae is the “chapelet de grains” in place of the basal fibre.

A method for detecting antibody activity in vitro against the invasive stages of E. tenella and E. maxima is described.Treatment of cultured chick kidney monolayers with serum (or a globulin fraction thereof) from immunized birds caused a reduction in the numbers of intracellular stages 24 or 48 h after inoculation of sporozoites. This reduction was seen when serum was incorporated in the culture medium at the time of sporozoite inoculation and also, but to a lesser extent, when the monolayers had been pretreated with the antibody-containing medium which was washed off prior to infection. The results correlated reasonably well with those obtained when the sera were tested in embryo (E. tenella) or in vivo (E. maxima).Similar treatment of cultured CAM monolayers in which infection with E. tenella was well established (101 h), did not greatly affect the development of the parasite. This suggests that the anti-coccidial activity is either effective against the sporozoite stages only, or is unable to affect parasites within cells.

DNA probes were developed for the detection and identification of 2 microsporidian parasites of marine fishes, Microgemma caulleryi (infecting the liver of the greater sand-eel, Hyperoplus lanceolatus) and Tetramicra brevifilum (infecting muscle, intestine and liver of the turbot, Scophthalmus maximus, a commercially important species). The probe-development procedure used is fast and straightforward, and readily applicable to the development of probes for other microsporidian species. First, genomic DNA of microsporidian spores was isolated and digested with the restriction enzyme Hind III. The fragments obtained were ligated into the vector pBluescript SK(+) and cloned in Escherichia coli. Appropriate inserts were identified and then amplified by PCR, using primers specific for regions adjacent to the Hind III restriction site in the vector sequence (and thus avoiding the need to develop primers specific for the inserts themselves). The copies were labelled with digoxigenin, for subsequent use as probes, during PCR itself. The specificity of candidate probes was tested in dot–blot hybridization assays, with the target DNA being (a) genomic DNA of the microsporidian from which the probe had been obtained, or of another species, (b) the corresponding genomic DNA in the phagemid, or (c) DNA from the corresponding host tissue. These assays identified a ca 1180 bp probe for M. caulleryi, denominated C38, and a ca 1363 bp probe for T. brevifilum, denominated F9. Similar assays designed to assess sensitivity indicated that F9 showed detectable binding to as little as 500 ng of T. brevifilum genomic DNA, and C38 to as little as 125 ng of M. caulleryi DNA; these results were obtained with detection of DIG by enzyme immunoassay (i.e. using a phosphatase-coupled anti-DIG antibody), and could no doubt be improved if a radioactive labelling and detection system were used. The probes developed in this study will greatly facilitate detection and identification of M. caulleryi and T. brevifilum in fish tissues, and may prove useful for identifying possible intermediate hosts used by these species.