Immunophilins comprise two protein families, cyclophilins (CYPs) and FK506-binding proteins (FKBPs), and are the major receptors for the immunosuppressive drugs cyclosporin A (CsA) and FK506 (tacrolimus), respectively. Most eukaryotic species have at least one immunophilin and some of them have been associated with pathogenesis of infectious or parasitic diseases or the action of antiparasitic drugs. The human malarial parasite Plasmodium falciparum has 13 immunophilin or immunophilin-like genes but the functions of their products are unknown. We set out to identify the parasite proteins that interact with the major CYPs, PfCYP19A and PfCYP19B, and the FKBP, PfFKBP35, using a combination of co-immunoprecipitation and yeast two-hybrid screening. We identified a cohort of putative interacting partners and further investigation of some of these revealed potentially novel roles in parasite biology. We demonstrated that (i) P. falciparum CYPs interacted with the heat shock protein 70, (ii) treatment of parasites with CYP ligands disrupted transport of the rhoptry-associated protein 1, and (iii) PfFKBP35 interacted with parasite histones in a way that might modulate gene expression. These findings begin to elucidate the functions of immunophilins in malaria. Furthermore, the known antimalarial effects of CsA, FK506 and non-immunosuppressive derivatives of these immunophilin ligands could be mediated through these partner proteins.

The epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle were Fasciola gigantica 28·2%, paramphistomes 62·8% and Schistosoma bovis 4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude > 1500 m) as compared with lowland (altitude < 1500 m) areas and was statistically significant (P-value = 0·000) for F. gigantica and paramphistomes but not for S. bovis. The snails collected included Lymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculata and Bellamya constricta with a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology of F. gigantica and paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.

FhCaBP2 is a Fasciola hepatica protein which belongs to a family of helminth calcium-binding proteins which combine an N-terminal domain containing two EF-hand motifs and a C-terminal dynein light chain-like (DLC-like) domain. Its predicted structure showed two globular domains joined by a flexible linker. Recombinant FhCaBP2 interacted reversibly with calcium and manganese ions, but not with magnesium, barium, strontium, copper (II), colbalt (II), iron (II), nickel, lead or potassium ions. Cadmium (II) ions appeared to bind non-site-specifically and destabilize the protein. Interaction with either calcium or magnesium ions results in a conformational change in which the protein's surface becomes more hydrophobic. The EF-hand domain alone was able to interact with calcium and manganese ions; the DLC-like domain was not. Alteration of a residue (Asp-58 to Ala) in the second EF-hand motif in this domain abolished ion-binding activity. This suggests that the second EF-hand is the one responsible for ion-binding. FhCaBP2 homodimerizes and the extent of dimerization was not affected by calcium ions or by the aspartate to alanine substitution in the second EF-hand. The isolated EF-hand and DLC-like domains are both capable of homodimerization. FhCaBP2 interacted with the calmodulin antagonists trifluoperazine, chlorpromazine, thiamylal and W7. Interestingly, while chlorpromazine and thiamylal interacted with the EF-hand domain (as expected), trifluoperazine and W7 bound to the DLC-like domain. Overall, FhCaBP2 has distinct biochemical properties compared with other members of this protein family from Fasciola hepatica, a fact which supports the hypothesis that these proteins have different physiological roles.

In wild rabbits (Oryctolagus cuniculus) on an estate in Perthshire, central Scotland, the seroprevalence of Toxoplasma gondii was 18/548 (3·3%). The wild rabbit could be a T. gondii reservoir and it has potential value as a sentinel of T. gondii in environmental substrates. Toxoplasma gondii was associated with female sex (P < 0·001) and with relatively heavy infections by Eimeria stiedae (P = 0·036). It was not associated with the intensity of coccidial oocysts, the severity of myxomatosis caused by the virus Myxomatosis cuniculi, the intensity of roundworm eggs, the year or season, rabbit age or distance from farm buildings. Coinfections could have been affected by gestational down regulation of type 1 T helper cells. A sudden influx or release of T. gondii oocysts might have occurred. This is the first report of T. gondii in any wild herbivore in Scotland and also the first report of lapine T. gondii as a coinfection with E. stiedae, M. cuniculi and helminths.

Mitochondrial DNA locus cytochrome oxidase I was used to asses intraspecific genetic diversity of a didymozoid species Didymosulcus katsuwonicola. Adult forms of this species live encapsulated in pairs in the gills of the reared Atlantic bluefin tuna (Thunnus thynnus). The life cycle of this food-borne parasites and its migration in the host tissues after releasing from the digestive tract to the definitive site in the gills are unknown. Our goal was to assess whether two encysted didymozoids share the same haplotype, indicative of a common maternal origin, as well as the extent of cross- in respect to self-fertilization strategy. Intraspecific comparison showed high haplotype diversity, while the presence of two matching haplotypes within a single cyst encompassed only 17% of sampled individuals. This infers that cross-fertilization between paired individuals within the cyst is more common mechanism than self-fertilization. Such hermaphroditic parasite's trait suggests the existence of intricate infection and reproduction mechanisms, presumably as an adaptation for successful fulfillment of their indirect life cycle through dissemination of genetically more diverse and consequently more fit offspring.

Visual displays of data in the parasitology literature are often presented in a way which is not very informative regarding the distribution of the data. An example being simple barcharts with half an error bar on top to display the distribution of parasitaemia and biomarkers of host immunity. Such displays obfuscate the shape of the data distribution through displaying too few statistical measures to explain the spread of all the data and selecting statistical measures which are influenced by skewness and outliers. We describe more informative, yet simple, visual representations of the data distribution commonly used in statistics and provide guidance with regards to the display of estimates of population parameters (e.g. population mean) and measures of precision (e.g. 95% confidence interval) for statistical inference. In this article we focus on visual displays for numerical data and demonstrate such displays using an example dataset consisting of total IgG titres in response to three Plasmodium blood antigens measured in pregnant women and parasitaemia measurements from the same study. This tutorial aims to highlight the importance of displaying the data distribution appropriately and the role such displays have in selecting statistics to summarize its distribution and perform statistical inference.

Intestinal diarrheagenic polyparasitic infections are among the major public health concerns in developing countries. Here we examined stool specimens by microscopy, DNA dot blot and polymerase chain reaction (PCR) to evaluate the co-infection of four principal protozoans among amoebic dysentery cases from Northeast Indian population. The multiplex PCR confirmed Entamoeba histolytica (8·1%), Entamoeba dispar (4·8%) and mixed infection of both the parasites (3·4%) in 68 of 356 stool specimens that were positive in microscopy and/or HMe probe based DNA dot blot screening. The prevailing parasite that co-exists with E. histolytica was Giardia duodenalis (34·1%), followed by Enterocytozoon bieneusi (22·0%), Cryptosporidium parvum (14·6%) and Cyclospora cayetanensis (7·3%, P = 0·017). Symptomatic participants (odds ratio (OR) = 4·07; 95% confidence interval (CI) = 1·06, 15·68; P = 0·041), monsoon season (OR = 7·47; 95% CI = 1·40, 39·84; P = 0·046) and participants with family history of parasitic infection (OR = 4·50; 95% CI = 1·16, 17·51; P = 0·030) have significant association with overall co-infection rate. According to molecular consensus, comprehensive microscopy yielded 3·4% (12/356) false-negative and 7·6% (27/356) false-positive outcome, suggesting an improved broad-spectrum PCR-based diagnostic is required to scale down the poor sensitivity and specificity as well as implementation of integrated control strategy.

Two mimotopes of Leishmania infantum identified by phage display were evaluated as vaccine candidates in BALB/c mice against Leishmania amazonensis infection. The epitope-based immunogens, namely B10 and C01, presented as phage-fused peptides; were used without association of a Th1 adjuvant, and they were administered isolated or in combination into animals. Both clones showed a specific production of interferon-gamma (IFN-γ), interleukin-12 (IL-12) and granulocyte/macrophage colony-stimulating factor (GM-CSF) after in vitro spleen cells stimulation, and they were able to induce a partial protection against infection. Significant reductions of parasite load in the infected footpads, liver, spleen, bone marrow and paws’ draining lymph nodes were observed in the immunized mice, in comparison with the control groups (saline, saponin, wild-type and non-relevant clones). Protection was associated with an IL-12-dependent production of IFN-γ, mediated mainly by CD8+ T cells, against parasite proteins. Protected mice also presented low levels of IL-4 and IL-10, as well as increased levels of parasite-specific IgG2a antibodies. The association of both clones resulted in an improved protection in relation to their individual use. More importantly, the absence of adjuvant did not diminish the cross-protective efficacy against Leishmania spp. infection. This study describes for the first time two epitope-based immunogens selected by phage display technology against L. infantum infected dogs sera, which induced a partial protection in BALB/c mice infected with L. amazonensis.

Mismatch in the phenology of trophically linked species as a result of climate warming has been shown to have far-reaching effects on animal communities, but implications for disease have so far received limited attention. This paper presents evidence suggestive of phenological asynchrony in a host-parasite system arising from climate change, with impacts on transmission. Diagnostic laboratory data on outbreaks of infection with the pathogenic nematode Nematodirus battus in sheep flocks in the UK were used to validate region-specific models of the effect of spring temperature on parasite transmission. The hatching of parasite eggs to produce infective larvae is driven by temperature, while the availability of susceptible hosts depends on lambing date, which is relatively insensitive to inter-annual variation in spring temperature. In southern areas and in warmer years, earlier emergence of infective larvae in spring was predicted, with decline through mortality before peak availability of susceptible lambs. Data confirmed model predictions, with fewer outbreaks recorded in those years and regions. Overlap between larval peaks and lamb availability was not reduced in northern areas, which experienced no decreases in the number of reported outbreaks. Results suggest that phenological asynchrony arising from climate warming may affect parasite transmission, with non-linear but predictable impacts on disease burden. Improved understanding of complex responses of host-parasite systems to climate change can contribute to effective adaptation of parasite control strategies.

Neuroinvasive larvae of the common dog and cat roundworms, Toxocara canis and Toxocara cati, may cause severe neurological and neuropsychological disturbances in humans. Despite their pathogenic potential and high prevalence worldwide, little is known about their cell-specific influences and cerebral host–pathogen interactions in neurotoxocarosis. To address this discrepancy, a co-culture system of viable larvae with murine neuronal (CAD), oligodendrocytal (BO-1) and microglial (BV-2) cell lines has been established. Additionally, murine adult brain slices have been co-cultured with Toxocara larvae to consider complex organotypic cell–cell interplay. Cytotoxicity of larval presence was measured enzymatically and microscopically. Microscopic evaluation using trypan blue exclusion assay revealed to be less reliable and sensitive than the lactate dehydrogenase activity assay. Ultimately, even low numbers of both T. canis and T. cati larvae have impaired survival of differentiated CAD cells, which morphologically resemble primary neurons. In contrast, viability of oligodendrocytal and microglial cells as well as brain slices was not impaired by larval presence. Therefore, immune-mediated mechanisms or trauma by migrating larvae presumably induce the in vivo pathology rather than acute cytotoxic effects. Conclusively, the helminthic larvae co-culture system presented here is a valuable in vitro tool to study cell-specific effects of parasitic larvae and their products.

At present many laboratories throughout the world are studying the chemotherapy and immunology of Schistosoma mansoni in laboratory hosts. Many workers judge the success or failure of their attempts to cure or immunize these hosts from the ratio of the number of living adult worms recovered to the number of infecting cercariae. This ratio is affected, however, not only by the efficacy of any treatment, but also by the methods used to infect the animals and to recover the worms. If these methods result in widely varying worm recoveries amongst the animals in any experimental group, then small but significant effects of treatment might well be missed. Alternatively, such large experimental groups must be used that the work becomes tedious to perform and depends upon the availability of a great deal of technical assistance. This paper describes techniques which are rapid and do not require great skill in their performance. More important, in our hands they have given very consistent results. In this respect, particularly, we believe that these techniques have advantages over others which are currently practised.

The techniques described here are those which were used in other investigations reported in this journal (Smithers & Terry, 1965a, b).

The strain of S. mansoni used throughout this work was isolated in Puerto Rico and was obtained through the courtesy of Dr W. B. DeWitt of the National Institutes of Health. The parasite is maintained in an albino strain of Australorbis glabratus (Newton, 1955). Snails are exposed individually to ten miracidia overnight at 27 °C.

Parasite dynamics can be mediated by host behaviours such as sociality, and seasonal changes in aggregation may influence risk of parasite exposure. We used little brown bats (Myotis lucifugus) captured during the autumn mating/swarming period to test the hypothesis that seasonal and demographic-based variation in sociality affect ectoparasitism. We predicted that ectoparasitism would: (1) be higher for adult females and young of the year (YOY) than adult males because of female coloniality; (2) increase for adult males throughout swarming because of increasing contact with females; (3) decrease for adult females and YOY throughout swarming because of reduced coloniality and transmission of individual ectoparasites to males; (4) be similar for male and female YOY because vertical transmission from adult females should be similar. Ectoparasitism was lowest for adult males and increased for males during swarming, but some effects of demographic were unexpected. Contrary to our prediction, ectoparasitism increased for adult females throughout swarming and YOY males also hosted fewer ectoparasites compared with adult and YOY females. Interestingly, females in the best body condition had the highest parasite loads. Our results suggest that host energetic constraints associated with future reproduction affect pre-hibernation parasite dynamics in bats.

Periodicity of occurrence in the final host has been observed in only a few of the known Acanthocephala of fish (Van Cleave, 1916; Steinstrasser, 1936; Komarova, 1950; Shulman & Shulman-Albova, 1953). The periodicity appears to be due to the simultaneous operation of a complex of physiological, developmental and ecological factors.

In the present investigation a detailed study has been made of both the occurrence and the developmental cycle of Echinorhynchus truttae in its hosts in a small trout stream, Afon Terrig, in North Wales. An attempt has also been made to ascertain to what extent some of the various and varying ecological and physiological factors influenced the incidence, degree of parasitization and the development of the worm in nature.

Samples of the intermediate host, Gammarus pulex pulex L., and the final host the brown trout, Salmo trutta L., were taken monthly at three points or stations where the stream was readily accessible. Station I was at Rhydtalog as far upstream as practicable. Station III was at the opposite end of the stream near Caegwydd and station II was about mid-way between the other two sampling points. To ensure that each host sample was examined in as fresh a condition as possible, autopsy of the intermediate host was completed before the definitive host was taken.

Within the first week of each month from November 1961 to January 1963, shrimps were taken from over a stretch of about 30 m at each station.

The Oxyuridae parasitic in Primates have a restricted host range with, in the wild, one species of parasite characteristic of one genus of host (Inglis, 1961). Under such conditions one would expect the hosts and their parasites to show parallel evolutionary trends. While this is not established in detail there is a broad correlation between the trends that can be established in the morphology of the parasites and the phylogenies of the hosts (Inglis, 1965).

Recently some parasites were reported which suggested that the Hapalidae could be considered primitive monkeys of the superfamily Ceboidea rather than specialized (Inglis & Dunn, 1964), but it was then stressed that, because few parasite records were available, the suggestion must be tentative. However, two further samples of pin-worms from Hapalidae have now become available which also support this suggestion. One sample is from Oedipomidas oedipus (reported by Menschel & Stroh (1963) as Enterobius minutus) and the other is from Callimico goeldii. Both samples represent new species which are described below.

The specimens from C. goeldii are particularly interesting because they represent a species which is clearly con-generic with those from the Hapalidae that have been studied. This suggests that Callimico should be referred to the family Hapalidae rather than to the family Cebidae or even, as is suggested by some authors, to a distinct family Callimiconidae.

Both the new species are referable to the genus Trypanoxyuris and the opportunity is taken to publish an illustration of the lateral view of the male tail of Trypanoxyuris callithricis (Fig. 1).

In the course of work designed to measure the extent to which methionine absorbed in one region of a tapeworm became distributed throughout the strobila, it was observed that, whereas, in saline, Hymenolepis diminuta lost previously absorbed methionine slowly, in the intestine of a rat the methionine was lost very rapidly. The fact that two worms containing initially the same amount of free methionine should, after a short period in different environments, contain utterly different quantities of methionine indicated that the quantity of a free amino acid present at any time is not simply dependent on the amount previously absorbed less the amount metabolized.

This observation has a bearing on several aspects of tapeworm physiology. Do tapeworms normally absorb amino acids from the intestine during periods of high concentration and release them when the concentration falls? If they do, the presence of tapeworms in the intestine could be beneficial to the host by extending the period over which an amino acid is available to the host, an important point as a mammal is unable to store amino acids for more than a few hours (Gitler, 1964). A knowledge of the environmental conditions which influence the level of free amino acids in a tapeworm, and thereby its ability to synthesize proteins, is obviously also of critical importance to workers attempting to grow worms in vitro.

Relatively little is known of the way in which the populations of monogenean parasites are related to the behaviour and physiology of their hosts or how such populations vary in composition over the year. Bychowsky (1957, trans. Hargis, 1961, p. 108) has described the results of studies upon six different fish hosts and parasites, while Llewellyn (1962) has studied two other species of Monogenea living on one host species. In all these investigations, the various ecological factors which influence the life cycles of the parasites have been determined.

Dogiel, Petrushevski & Polyanski (1961, p. 14) referred to a previous population study of Discocotyle sagittata on a host Coregonus lavaretus in Lake Ladoga, Russia. The parasite was said to breed in July and August, while in September broods of young and old parasites overlapped. The large individuals disappeared in October and November and this ‘death of the older generation’ was taken to indicate that the parasites had a life span of only one year.

The only relevant work available when the present study was commenced was the population study of the monogeneans Gastrocotyle trachuri and Pseudaxine trachuri by Llewellyn and as this concerned a marine host, it was of obvious interest to investigate the population dynamics of a parasite of a freshwater fish. Discocotyle sagittata was chosen because the biology of the British host, the brown trout (a different host from that in the Russian study of Discocotyle), has been intensively studied for many years. It was thought that this would be of advantage in attempting to relate any seasonal fluctuations in the parasite population to the biology of the host.