Entamoeba histolytica is the protozoan parasite that causes human amoebiasis. It is one of the leading parasitic disease burdens in tropical regions and developing countries, with spread to developed countries through migrants from and travellers to endemic regions.

Understanding E. histolytica’s invasion mechanisms requires an understanding of how it interacts with external cell components and how it engulfs and kills cells (phagocytosis). Recent research suggests that optimal phagocytosis requires signalling events from the cell surface to the nucleus via the cytoplasm, and the induction of several factors that are transported to the plasma membrane. Current research in other protozoans suggests the presence of proteins with nuclear localization signals, nuclear export signals and Ran proteins; however, there is limited literature on their functionality and their functional similarity to higher eukaryotes.

Based on learnings from the development of antivirals, nuclear transport elements in E. histolytica may present viable, specific, therapeutic targets.

In this review, we aim to summarize our limited knowledge of the eukaryotic nuclear transport mechanisms that are conserved and may function in E. histolytica.

Cystic echinococcosis (CE) is one of the most common zoonotic diseases worldwide, particularly in rural areas. This study aimed at the identification of the genotype/species belonging to Echinococcus granulosus sensu lato (s.l.) specimens in retrieved percutaneously from the human host and to investigate their relationship with cyst characteristics. The genetic identification of cyst material was performed by mt-CO1 gene polymerase chain reaction, and confirmed via sequencing. A total of 110 CE cysts were identified as E. granulosus s.l. In detail, 104 belonged to E. granulosus sensu stricto (G1 and G3) and six isolates were in the E. canadensis cluster (G6/7). All clusters were tested for the relationship between demographics, cyst features and genetic diversity. The relationship between genetic variation and certain clinical characteristics such as cyst volume and location were statistically significant for G6/7 cluster. Further studies are required with a larger sample set to investigate the relationship between the genetic variability of E. granulosus s.l. and cyst features.

This study aimed to assess the contribution of hosts characteristics (rodents and marsupials) in the organization of ectoparasite communities present in woodland patches in western central Brazil. We verified the effect of host species, sex, body mass and vertical strata in addition to the role of seasonality on the ectoparasite composition, richness and abundance. The total sampling effort was 22 032 trap-nights equally distributed in 54 woodland patches. Variance partition and principal coordinate analysis were used to verify the existence of significant relationships between response variables and predictors. As expected, host species was the most important variable in ectoparasite community assembly. The composition, richness and abundance of mites and lice were highly influenced by host species, although higher for mites than for lice. Host body mass had a determining role on the richness and abundance of tick species. Vertical stratification and seasonality had weak influence, while the sex of the host had no influence on the organization of these communities. The results are closely related to the evolutionary characteristics of the species involved, as well as with local environmental characteristics of the study area.

The acanthocephalan fauna of Australian freshwater fishes was documented from field surveys, a literature survey and examination of specimens registered in Australian museums. From the 4030 fishes, representing 78 of the 354 Australian freshwater fish species (22%), examined for infection seven species of acanthocephalan were recovered. These species comprised five endemic species, three in endemic genera, two species in cosmopolitan genera, one species not fully identified and 1 putative exotic species recovered from eight species of fish. Of these Edmonsacanthus blairi from Melanotaenia splendida, was the only acanthocephalan found at a relatively high prevalence of 38·6%. These findings are indicative of a highly endemic and possibly depauperate acanthocephalan fauna. Species richness was higher in the tropical regions than the temperate regions of the country. Exotic acanthocephalan species have either not been introduced with their exotic hosts or have been unable to establish their life cycles in Australian conditions. Consequently, acanthocephalans have not yet invaded endemic Australian fish hosts.

Factors that drive parasite specificity and differences in infection dynamics among alternative host species are important for ecology and evolution of host–parasite interactions, but still often poorly known in natural systems. Here, we investigated spatiotemporal dynamics of infection, host susceptibility and parasite-induced changes in host phenotype in a rarely explored host–parasite system, the Australapatemon sp. trematode infecting two sympatric species of freshwater leeches, Erpobdella octoculata and Helobdella stagnalis. We show significant variation in infection abundance between the host species in both space and time. Using experimental infections, we also show that most of this variation likely comes from interspecific differences in exposure rather than susceptibility. Moreover, we demonstrate that the hiding behaviour of E. octoculata, but not that of H. stagnalis, was impaired by the infection irrespective of the parasite abundance. This may increase susceptibility of E. octoculata to predation by the final avian host. We conclude that differences in patterns of infection and in behavioural alterations among alternative sympatric host species may arise in narrow spatial scales, which emphasises the importance of local infection and transmission dynamics for parasite life cycles.

Experimental infections of mallards (Anas platyrhynchos L.) with Typhlocoelum cucumerinum sisowi (Skrjabin, 1913) and of canvasbacks (Aythya valisineria (Wilson)) with Typhlocoelum cucumerinum cucumerinum (Rudolphi, 1809) revealed significant differences in various parameters of the life-cycle in the definitive host. Both T. c. sisowi and T. c. cucumerinum migrate to the trachea via the abdominal cavity, air sacs and lungs, although T. c. cucumerinum migrate more quickly and more synchronously than T. c. sisowi. Typhlocoelum c. sisowi has a shorter expected life-span than T. c. cucumerinum but grows and reaches maturity more quickly than T. c. cucumerinum. Evidence suggests that T. c. cucumerinum has a higher fecundity than T. c. sisowi. These differences in the patterns of migration, growth and development are related not only to differences between the two host species but also to differences intrinsic to the parasites, and serve to provide biological support for considering them as separate sub-species.

(1) An account is given of a serious infestation in sheep and lambs by Ixodes ricinus in the uplands of Denbighshire, North Wales.

(2) This infestation was accompanied by serious disturbance of health resulting in the general deterioration of the flock and the death of lambs.

(3) Experimental dippings were commenced in 1924, using a special “short-interval” arsenical dip supplied by the Cooper Technical Bureau, London. Serial dippings were made each spring at five-day intervals. When possible an early autumn series was conducted.

(4) The objects were (a) to control the infestation, (b) to control the diseased condition, and (c) to attempt to eradicate ticks from the land.

(5) The control of both the ticks and the disease were easily effected. A few sporadic cases of disease did occur during the course of the experiment.

(6) Eradication has not yet been accomplished, but the average number of ticks was reduced from 121 per animal in May 1924 to 0-96 per animal in July 1926.

(7) It is therefore suggested that short-interval dipping for serious tick infestation in sheep is practicable on British hill farms, and that resultant mortality from disease can thereby be reduced.

The glycolipids of Ascaris suum represent either neutral, zwitterionic or acidic structures. The acidic fraction comprises a sulphatide and an unusual phosphoinositolglycosphingolipid (Lochnit et al. 1998b). The sulphatide was previously localized to the hypodermis, contractile zone of somatic muscle cells and the external musculature of the female uterus, whereas the presence of the phosphoinositolglycosphingolipid species was restricted to the intestine. The neutral and zwitterionic components belong to the arthro-carbohydrate series, which are substituted in their zwitterionic structures by phosphocholine (PC) and in one glycolipid by an additional phosphoethanolamine residue. In previous immunohistochemical localization studies, however, the chemical nature of the PC-substituted biomolecules has not been investigated in detail. Here, we report on the immunohistochemical localization and differentiation of phosphocholine-containing structures into lipid- and protein-bound species in adult A. suum. The patterns of immunostaining, obtained with a PC-specific monoclonal antibody and anti-zwitterionic glycolipid hyperimmune serum in the female worm, indicated a parallel organ distribution for glycolipid- and protein-bound PC-epitopes. Immunoreactivity was localized to specific tissues of the body wall, intestine and reproductive tract. This is the first report of surface-located PC-epitopes for ascarids. The patterns of immunolabelling obtained with antibodies directed against the unsubstituted arthro-carbohydrate series backbone suggested that the glycolipid-bound epitope was restricted to the hypodermis, whilst the protein-bound antigenic determinant resembled that for PC.

The material recorded and described in the present paper consists not only of the specimens in the South Australian Museum, but largely an immense number of specimens sent to the writer by Mr F. H. Taylor of the Department of Tropical Health, Sydney. To him, my best thanks are due for the opportunity to examine and describe this material. Types of the new species are in the South Australian Museum and paratypes amongst the material returned to the Department of Tropical Health, Sydney.

Parasitic helminths have an absolute requirement for carbohydrate for their energy metabolism, there being no significant contribution from fatty acid or amino acid catabolism. There is no significant synthesis of glucose or glycogen from non-hexose precursors in helminths and so they are dependent on dietary carbohydrate. Characteristically parasitic helminths break down glycogen or glucose via linear anaerobic pathways to give reduced organic end-products, usually acids such as lactate, acetate, succinate and propionate or more rarely alcohols such as ethanol, propanol and acetoin (Barrett, 1984).

An account is given of the preparation of Elford's gradocol membranes and their application in the study of plant viruses. The technique is discussed step by step and the chief sources of error are indicated. It is shown that plant virus suspensions clog the membranes, and suggestions are made for the preparation of those suspensions for filtration. The effect of virus content, purification and pH of virus fluids upon their filtration is discussed.

Oligosaccharides are broadly present on Leishmania cell surfaces. They can be useful for the leishmaniases diagnosis and also helpful in identifying new cell markers for the disease. The disaccharide Galα1-3Galβ is the immunodominant saccharide in Leishmania cell surface and is the unique non-reducing terminal glycosphingolipids structure recognized by anti-α-Gal. This study describes an enzyme-linked immunosorbent assay (ELISA) used to measure serum levels of anti-α-galactosyl (α-Gal) antibodies in patients with cutaneous leishmaniasis (CL). Optimal ELISA conditions were established and two neoglycoproteins (NGP) containing the Galα1-3Gal terminal fraction (Galα1-3Galβ1-4GlcNAc-HAS and Galα1-3Gal-HAS) and one Galα1-3Gal NGP analogue (Galα1-3Galβ1-3GlcNAc-HAS) were used as antigens. Means of anti-α-Gal antibody titres of CL patients were significantly higher (P < 0.05) than the healthy individuals for all NGPs tested. Sensitivity and specificity of all NGPs ranged from 62.2 to 78.4% and 58.3 to 96.7%, respectively. In conclusion, the NGPs can be used for CL diagnosis.

Social wasps can face many challenges during their colony cycle, including the presence of parasites. The order Strepsiptera is among the main parasites of the wasp genus Polistes. The aim of this study was to evaluate the effect of an endoparasite species on the host Polistes ferreri, with the hypothesis that females of this social wasp would undergo morphophysiological alterations as well as changes in their cuticular chemical profile caused by the obligate endoparasite. On average, parasitism was found in 10% of the colonies studied. All the parasitized females showed filamentous ovarioles without developing oocytes, which indicates a physiological castration. Moreover, the endoparasites present in the gaster of females caused its volume to increase, and the presence of endoparasites changed the cuticular chemical profiles of females, confirming our hypothesis. It is likely that this parasitism effect could hamper the maintenance of wasp colonies.

A precise knowledge of the geographical distribution of Ornithodorus moubata is very desirable, as it bears directly upon the distribution of the Relapsing Fever of Tropical Africa. It therefore appears desirable to publish the accompanying map and a list of places showing the distribution of the tick. Both the map and the list are, however, of necessity far from perfect.

Our knowledge of the Indian Rhynchobdellid leeches is still in its infancy, and the little that we have, we owe to the researches of Harding, Kaburaki, and Moore. After the publication of the Hirudinea volume by Harding & Moore (1927) in the Fauna of British India Series, Bhatia (1930a, b, 1934, 1939), Chelladurai (1934) and Raj (1951, 1954a, b) have contributed to the systematics of this group. The present work has been undertaken with a view to advancing further our knowledge of Indian Rhynchobdellid leeches. In this work, the neurosomic theory of somite limits launched independently by Castle (1900) and Moore (1900) has been followed in counting the annular composition of somites. This paper, the first of the series, deals with the description of four Glossiphonid leeches, of which three are new to science, while the fourth one is of zoogeographical importance.

Emerging evidence started to delineate multiple layers of memory B cells, with distinct effector functions during recall responses. Whereas most studies examining long-lived memory B cell responses have focussed on the IgG+ memory B cell compartment, IgM+ memory B cells have only recently started to receive attention. It has been proposed that unlike IgG+ memory B cells, which differentiate into antibody-secreting plasma cells upon antigen re-encounter, IgM+ memory B cells might have the additional capacity to establish secondary germinal centre (GC) responses. The precise function of IgM+ memory B cells in the humoral immune response to malaria has not been fully defined. Using a murine model of severe malaria infection and adoptive transfer strategies we found that IgM+ memory B cells induced in responses to P. berghei ANKA readily proliferate upon re-infection and adopt a GC B cell-like phenotype. The results suggest that that IgM+ memory B cells might play an important role in populating secondary GCs after re-infection with Plasmodium, thereby initiating the induction of B cell clones with enhanced affinity for antigen, at faster rates than naive B cells.

Ribonucleic acid which was normally present in Toxoplasma gondii was found to disappear or become undemonstrable during the action of the dye-test antibodies using cytochemical techniques. A possible explanation for the mechanism of the dye test has been put forward based on this evidence.