The population growth of endangered whooping cranes (Grus americana) is not consistent with species recovery goals, and the impact of parasite infection on whooping crane populations is largely unknown. Disease ecology and epidemiology research of endangered species is often hindered by limited ability to conduct invasive sampling on the target taxa. Accordingly, we hypothesized that sandhill cranes (Grus canadensis) would be a useful surrogate species to investigate the health impacts of Haemosporida infection in whooping cranes. Our goal was to compare the prevalence and diversity of Haemosporida infection between whooping cranes and sandhill cranes. We detected an overall infection prevalence of 83·6% (n = 61) in whooping cranes and 59·6% (n = 47) and 63·6 (n = 22) in two sympatric sandhill crane populations captured in Texas. Prevalence was significantly lower in allopatric sandhill cranes captured in New Mexico (12·1%, n = 33). Haemoproteus antigonis was the most abundant haemoparasite in cranes, present in 57·4% of whooping cranes and 39·2% of sandhill cranes; Plasmodium and Leucocytozoon were present at significantly lower levels. The high prevalence of Haemosporida in whooping cranes and sympatric sandhill cranes, with shared parasite lineages between the two species, supports sandhill cranes as a surrogate species for understanding health threats to endangered whooping cranes.

In this paper we derive from first principles the expected body sizes of the parasite communities that can coexist in a mammal of given body size. We use a mixture of mathematical models and known allometric relationships to examine whether host and parasite life histories constrain the diversity of parasite species that can coexist in the population of any host species. The model consists of one differential equation for each parasite species and a single density-dependent nonlinear equation for the affected host under the assumption of exploitation competition. We derive threshold conditions for the coexistence and competitive exclusion of parasite species using invasion criteria and stability analysis of the resulting equilibria. These results are then used to evaluate the range of parasites species that can invade and establish in a target host and identify the ‘optimal’ size of a parasite species for a host of a given body size; ‘optimal’ is defined as the body size of a parasite species that cannot be outcompeted by any other parasite species. The expected distributions of parasites body sizes in hosts of different sizes are then compared with those observed in empirical studies. Our analysis predicts the relative abundance of parasites of different size that establish in the host and suggests that increasing the ratio of parasite body size to host body size above a minimum threshold increases the persistence of the parasite population.

The symptoms produced by a green strain of tomato streak virus 1 upon a variety of Solanaceous plants are described. A yellow variant of the streak virus which appears to have arisen during the culturing of the green strain is also described. This variant produces local yellow spots upon all inoculated leaves of White Burley tobacco.

Healthy tobacco plants have been infected with the green strain of the streak virus by spraying them with a virus suspension from an atomiser.

The behaviour of the green and yellow virus strains when, co-existing in the tobacco plant is discussed.

Filtration through graded collodion membranes shows that the two strains have different filtration end-points and that therefore they can be separated by this means. The difference in filterability is considered to be a quantitative effect and cannot yet be assigned to difference in particle size.

Immunity tests have shown that a complete cross-immunity exists between the green and yellow strains of streak themselves, between them and two other strains of streak which produce local lesions and between the green and yellow strains and tobacco virus 1. No immunity was found between the streak viruses and those of tobacco necrosis, tobacco ringspot, tomato spotted wilt and potato virus X.

The yellow strain of streak produced local yellow spots on mature leaves of White Burley tobacco. This suggests that the chlorophyll is actually attacked by the virus, and that the formation of the chlorotic spots is not due merely to the inhibition of plastid formation by the virus.

The protozoan parasite Toxoplasma gondii possesses a triple surface membrane called the pellicle. This is made of an outer plasmalemma and an inner membrane complex lying under the plasmalemma. Using a high salt glycerol treatment followed by sonication, we have obtained a partial dissociation of the pellicle. A plasmalemma-enriched fraction was isolated on 0·7M sucrose. It was identified by immunodetection of the tachyzoite major surface antigens. Protein content, resolved by SDS–PAGE, revealed that the surface protein SAG1 is the major component of the plasmalemma. The plasmalemma fraction is made of small vesicles (20–100 nm) which possess a low density (1·085–1·090 g/cm3 in sucrose) contrasting with other eukaryotic plasma membranes (1·12–1·16 g/cm3).

Steroids have been shown to be beneficial in patients and mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection; however, the mechanism for this beneficial effect is unknown. We speculated that the effect of steroids in eosinophilic meningitis caused by A. cantonensis infection may be mediated by the downregulation of matrix metallopeptidase-9 (MMP-9) and oxidative stress pathways via glucocorticoid receptors (GRs). We found blood–brain barrier (BBB) dysfunction in mice with eosinophilic meningitis 2–3 weeks after infection as evidenced by increased extravasation of Evans blue and cerebrospinal fluid (CSF) albumin levels. The administration of dexamethasone significantly decreased the amount of Evans blue and CSF albumin. The effect of dexamethasone was mediated by GRs and heat shock protein 70, resulting in subsequent decreases in the expressions of nuclear factor kappa B (NF-κB), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) in the CSF and brain parenchymal after 2 weeks of steroid administration. Steroid treatment also decreased CSF/brain homogenate MMP-9 concentrations, but had no effect on CSF MMP-2 levels, indicating that MMP-9 rather than MMP-2 played a major role in BBB dysfunction in mice with eosinophilic meningitis. The concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG) gradually increased after 1–3 weeks of infection, and the administration of dexamethasone significantly downregulated the concentration of oxidized derivative 8-OHdG in CSF. In conclusion, increased 8-OHdG and MMP-9 concentrations were found in mice with eosinophilic meningitis caused by A. cantonensis infection. The effect of dexamethasone was mediated by GRs and significantly decreased not only the levels of 8-OHdG and MMP-9 but also NF-κB, JNK and ERK.

Avian trichomonosis is an architypal disease of wild columbids and those birds that predate them. Increasingly though, it has been reported in passerines; a recent and ongoing epidemic in the chaffinches and greenfinches of Europe and outbreaks amongst house finches, American goldfinches and purple finches in North America. The parasite, Trichomonas gallinae, causes lesions in the upper respiratory tract which can cause mortality associated with dehydration and emaciation. This paper reports for the first time, the widespread, endemic and often asymptomatic infection of common mynah (Acridotheres tristis) around the Faisalabad District, Pakistan. Parasite typing was used to investigate the potential for transmission among the frequently sympatric species. Type C parasites were found in mynah, and while this is analagous to the pandemic finch strain which is Type A, it is the first known example of passerine infections of this parasite genotype. Subtype analysis showed the strain to be C4 a subtype which has a widespread distribution in columbids.

1. A detailed morphological study has been made of the amoeba, parasitic in larvae of Trichocera, which was described by Keilin (1917) under the name Entamoeba mesnili.

2. This study shows that the parasite cannot be included in any of the existing genera of parasitic amoebae and the new genus Dobellina is formed for it. A diagnosis of the genus Dobellina is given.

3. In Cambridge Trichocera larvae were never found infected with Dobellina mesnili earlier in the winter than January and the infection rate appears to be highest (up to 92%) towards the end of January and in February. Infected larvae were never found later in the year than May.

Hyalomma monstrosum, Nuttall and Warburton, 1907 (Proc. Camb. Phil. Soc., Vol. XIV. pp. 392–416, figs. 41–45 of the ♂). The female is here described for the first time.

The 1981 Autumn Symposium (held at the Zoological Society, London, on 31 October) was a new departure for the British Society for Parasitology in that Cambridge University Press have taken over publication of the proceedings. The style and layout of the contributions have been changed in order to conform with the format currently used in the journal Parasitology. The symposia proceedings will now be published as separate issues of Parasitology but with their own distinctive colour and cover design. The proceedings will be available by subscription to the journal or separately. Furthermore, the meeting organizers will in future be responsible for editing the symposia: assistance will be by Drs Taylor and Muller during a transition period.

1. Echinobothrium acanthinophyllum sp.nov. occurs in the spiral valve of Raja montagui Fowler. E. affine Diesing was also present.

2. E. acanthinophyllum possesses 23 large hooks in each apical group flanked by 4 small hooks on either side. There are 13 spines in each of the 8 longitudinal rows on the cephalic peduncle and 13 testes in each proglottid. The ripe eggs aggregate into clusters of 8–10, which fill the gravid uterus.

3. Euzet's key is revised to include the 9 species of the genus.

A limited number of metacestodes of Hymenolepis diminuta from Tenebrio molitor had host plasmatocytes and cell debris of coagulocyte origin associated with the microvillar surface. There was evidence of phagocytosis of microvilli by plasmatocytes, involving clathrin-like endocytotic vesicles. In contrast to these otherwise ‘normal’ cysticercoids, occasional batches were ‘sticky’ and, on flushing into saline, rapidly developed large bladders possibly associated with osmotic stress. In addition, numerous small surface blebs were present. These ‘surface-stressed’ cysticercoids also had host plasmatocytes and cell debris associated with the bladder bases and the blebs, and phagocytosis of microvilli was observed. In no case had precipitation of haemolymph, melanization or encapsulation (features typical of the insect immune response) occurred. The possibility that the limited host response indicates a spatially restricted impairment of the surface compatibility of the parasite, and thus insufficient to elicit the full immune response, is discussed.

An HMG2-like protein was purified from nuclear extracts of adult Schistosoma mansoni. Investigation of the amino acid composition of the schistosome HMG2-like protein showed that glutamic acid, glycine, aspartic acid and lysine were the most abundant. Carbohydrate analysis showed that the HMG2-like protein presented a low degree of glycosylation, galactose or glucose being the major monosaccharide constituent. Incubation of live schistosomes with 32P followed by isolation of nuclear proteins showed that the HMG-2 like protein could be phosphorylated. Partial sequence analysis of cyanogen bromide peptides revealed the occurrence of a phosphorylation consensus motif. The schistosome HMG2-like protein was found to bind preferentially to single-stranded DNA. The results suggest that the major non-histone S. mansoni nuclear protein belongs to the HMG family.

1. Herpetomonas ludwigi was found in 5–6% of larvae of Tipula paludosa in two out of three populations examined.

2. The developmental cycle is confined to the enteric caeca of the host. From a study of smears and sections of these organs it was concluded that the life cycle was composed of the following stages:

(a) A long-flagellated leptomonad stage which is short-lived and probably represents the form in which the flagellate enters the caeca from the mid-gut lumen; (b) a haptomonad or attached form in which the flagellum is short or absent: this probably represents the growth phase of the organism; (c) a crithidial phase which arises by a series of divisions from the haptomonad; (d) a small trypaniform stage which breaks free and lives in the lumen of the caecum; (e) a precystic flagellate; and (f) a small, thick-walled cyst.

3. This species is characterized by its restriction to the enteric caeca and the short duration of free swimming as opposed to attached stages in the life history. This second feature is a corollary of the first. The periodic contraction of the enteric caeca makes attachment obligatory throughout the growth and division stages. These contractions also serve to void cysts into the mid-gut whence they leave the larva with its dejecta to infect other larvae.

A simple semi-mechanical sieving apparatus is described which rapidly concentrates helminth eggs from relatively large volumes of faeces. Tests showed the percentage recoveries of N. battus eggs after sieving 500, 750 and 1000 ml of diluted ovine faeces were 94·1, 88·1 and 84·8 respectively; for T. suis, Oesophagostomum spp. and H. rubidus eggs from 1000 ml. of porcine faeces, the percentage recovery was 94·8 for T. suis and 94·7 for the latter two worms. T. trichuira eggs have also been separated from human faeces using this apparatus.

In Tunisia and other North African countries, there is a lack of knowledge about parasite biodiversity within threatened wild ruminants and there are not any studies on their gastrointestinal nematodes. Thus the aim of this study was to identify gastrointestinal fauna in the faecal samples of Tunisian wild ruminants. A total of 262 faecal samples were collected from domestic sheep and goat, and wild ruminants (Addax, Barbary sheep, Barbary red deer, Dorcas gazelle, Slender-horned gazelle and Scimitar-horned Oryx) living in protected areas. Samples were examined with floatation (saturated sodium chloride solution), polymerase chain reaction and sequencing of the second internal transcribed spacer region of the rDNA. Microscopic analysis allowed the identification of only Nematodirus genus or molecular tools allowed a first identification of five gastrointestinal nematode species in North African wild ruminants: Chabertia ovina (1.6%), Camelostrongylus mentulatus (1.6%), Marshallagia marshalli (4.7%), Nematodirus helvetianus (62.5%) and Nematodirus spathiger (29.7%). This study reported the first records of C. mentulatus and M. marshalli in Addax and of M. marshalli in Dorcas gazelle and it was the first reported record of N. helvetianus and M. marshalli in Tunisia.

Dipetalonema sprenti n.sp. is described from specimens removed from the peritoneal cavity of beavers (Castor canadensis) from Ontario, Canada. D. sprenti is found to be similar to D. arbuta Highby, 1943, but differs in the larger size of the eggs and fully developed embryos, the greater lengths of the spicules, the arrangement of the medial post-anal papillae, the more posterior position of the nerve ring, the greater length of the tail and in the considerably larger size of the body. D. sprenti is the fourth species of Dipetalonema described from rodents.

Records are given of helminth infection found by the dissection of 122 waders belonging to 19 species, some migratory and some resident in Australia. In the examination of the nematodes from these, and some other hosts, the following species were identified and described: Capillaria triloba (Linst.) (Lobibyx novae-hollandiae, Himantopus leucocephalus, Recurvirostra novaehollandiae); Capillaria recurvirostrae sp.nov. (R. novaehollandiae); Amidostomum chevreuxi Seurat (H. leucocephalus); Porrocaecum lobibycis (L. novaehollandiae); Contracaecum spiculigerum (Rud.) (H. leucocephalus); Schistorophus longicornis (Hemp. & Ehr.), and Sciadiocara umbellifera (Molin) (Calidris canutus); Schistorophus limosae sp.nov. and Viktorocara limosae sp.nov. (Limosa lapponica); Viktorocara sp. (Calidris canutus); Echinuria heterobrachiata Wehr (Cladorhynchus leucocephalus, Charadrius alexandrinus, Erolia ruficollis); Chevreuxia australis Johnston & Mawson (Charadrius melanops); Skrjabinoclava horrida (Rud.) (Charadrius rubricollis, C. alexandrinus); Streptocara crassicauda (Creplin) (Ch. alexandrinus); Stello-caronema charadrii sp.nov. (Ch. cucullata); S. glareolae sp.nov. (Glareola isabella); Tetrameres nouveli (Seurat) (Him. leucocephalus, Ch. alexandrinus, Recurvirostra novaehollandiae); T. cladorhynchi sp.nov. (C. leucocephalus); T. calidris sp.nov. (C. canutus); T. lobibycis sp.nov. (L. novaehollandiae); T. scolopacidis sp.nov. (Erolia acuminata, E. ruficollis, Tringa glareola); Pseudaproctella sp. (Lobibyx miles).

I am particularly indebted to the Director, Dr Peter Crowcroft, and the staff of the South Australian Museum; without their help it would have been impossible to obtain many of the parasites. Some birds were presented by Mrs Joan Paton and some by Mr Max Waterman. Specimens from Limosa lapponica were lent by the School of Public Health and Tropical Medicine in Sydney, from Lobibyx novaehollandiae (from Queensland) by Dr John Pearson of the Department of Parasitology of the University of Queensland, and from Lobibyx miles from Dr M. J. Mackerras of the C.S.I.R.O., Division of Entomology, in Canberra. Mr Condon, Curator of Birds in the South Australian Museum, has helped with information on the habits and correct names of the birds, and my colleague, Dr S. J. Edmonds, with names of new species. I also wish to thank Dr W. G. Inglis of the British Museum (Nat. Hist.) who was good enough to read the paper.

The holotype and paratypes of Viktorocara limosae sp.nov. and Schistorophus limosae sp.nov. are in the School of Public Health and Tropical Medicine in Sydney. Other holotypes are in the South Australian Museum, and paratypes in the Helminthological Collection of the Zoology Department of the University of Adelaide.

Contracaecum sp. nematodes are important parasites of fish eating birds that can cause animal health problems. In the present study, specimens of Contracaecum rudolphii sensu lato, from the great cormorant Phalacrocorax carbo sinensis from Sardinia, were characterized based on morphological and molecular data. The morphological analysis allowed to identify all the fourth stage larvae (n = 1918) as Contracaecum sp., and adults, male (n = 5845) and female (n = 8312), as C. rudolphii sensu lato. Population genetics and phylogenetic relationships were inferred based on mitochondrial and nuclear markers. Multiple sequence alignment of the ribosomal internal transcribed spacer showed the coexistence of C. rudolphii A (n = 157), C. rudolphii B (n = 22) and a rare heterozygote of these species. Moreover, mitochondrial markers, namely NADH dehydrogenase subunits I (nad1), cytochrome c oxidase subunit (cox1 and cox2) and small subunit of rRNA (rrnS), showed that the studied C. rudolphii A populations had undergone bottleneck, or founder effect event, subsequent to a rapid population growth and expansion. The observed heterozygote is with a mitochondrial pattern of C. rudolphii B. Although, both Contracaecum species showed high genetic diversity, no genetic structure between localities was detected. Phylogenetic reconstructions supported the paraphyly of the avian Contracaecum species including C. ogmorhini (parasite of otariids).

A cDNA library was constructed from muscle larvae of Trichinella pseudospiralis. A cDNA clone, designated as Tp8 contained a cDNA transcript of 1326 bp length with a single open reading frame, which encoded 303 amino acid residues (34187 Da, estimated molecular mass). The predicted amino acid sequence of the clone had an identity of approximately 60% to the Rcd1 (Required cell differentiation 1) -like proteins among a wide range of organisms. Real-time quantitative polymerase chain reaction results showed that the transcription level of Tp8 gene reached the highest value in adult worms, and that the transcription level in muscle larvae before stichosome formation was higher than in muscle larvae after stichosome formation. The recombinant Tp8 protein migrated at 37 kDa and reacted to antibody against T. pseudospiralis excretory-secretory (E-S) products and sera from mice infected with T. pseudospiralis. An antibody against the Tp8 recombinant protein could stain proteins migrating at approximately 34 kDa (which is the expected size from the sequence) on Western blotting of E-S products from muscle larvae. An immunocytochemical study showed that the Tp8 protein was present within the stichocyte of muscle larvae and adults worms.