In my previous paper on the body louse (1916) many points of morphological interest were necessarily left in abeyance and mention was made that certain statements in it were open to correction. Further work has rendered correction possible. While working in France, to ascertain whether Pediculus humanus was a carrier of the spirochaete of Weil's disease, opportunity was taken to investigate those organs of the louse in which the spirochaete might lodge and the afferent and efferent channels through which it might pass. The enquiry did not demonstrate the presence of the spirochaete in the body louse, but incidentally a detailed knowledge of the mechanism of feeding was obtained and is here presented. Since the main conclusions of this paper were reached (December, 1916) I have read Harrison's paper, “A Preliminary Account of the Structure of the Mouth-Parts in the Body-Louse,” and while much of the following verifies his statements, we differ on certain important points regarding the structure of the mouth-parts and musculature.

Current treatments for different clinical forms of leishmaniasis are unsatisfactory, highly toxic and associated with increasing failure rates resulting from the emergence of resistant parasites. Leishmania (Viannia) braziliensis is the main aetiological agent of different clinical forms of American tegumentary leishmaniasis, including the mucosal form for which treatment has high failure rates. The aim of this work was to investigate the activity of the Morita-Baylis-Hillman adduct, methyl 2-{2-[hydroxy(2-nitrophenyl)methyl])acryloyloxy} benzoate in vitro against isolates of L. (V.) braziliensis obtained from patients with different clinical manifestations of tegumentary leishmaniasis: localized cutaneous leishmaniasis, mucosal leishmaniasis and disseminated cutaneous leishmaniasis. The adduct effectively inhibited the growth of promastigotes of the different isolates of L. (V.) braziliensis (IC50 ⩽ 7·77 μg/ml), as well as reduced the infection rate of macrophages infected with these parasites (EC50 ⩽ 1·37 μg/ml). It is remarkable to state that the adduct was more effective against intracellular amastigotes (P ⩽ 0·0045). The anti-amastigote activity correlated with an immunomodulatory effect, since the adduct was able to decrease the production of IL-6 and IL-10 by the infected macrophages. However, its effect was independent of nitric oxide production. This work demonstrates the anti-leishmanial activity of methyl 2-{2-[hydroxy(2-nitrophenyl)methyl])acryloyloxy} benzoate and suggests its potential in the treatment of human infections caused by L. (V.) braziliensis.

The term Pediculosis denotes the pathological condition brought about by infestation with Pediculus humanus, either the head or the body or both of these being affected. Pediculosis may lead directly or indirectly to secondary infections of various kinds. P. humanus (corporis and capitis) has been shown to be the carrier of two important diseases affecting man, namely typhus and relapsing fever.

The need for new drugs to treat microbial infections is pressing. The great progress made in the middle part of the twentieth Century was followed by a period of relative inactivity as the medical needs relating to infectious disease in the wealthier nations receded. Growing realisation that anti-infectives are needed in many parts of the world, to treat neglected diseases as well as to combat the burgeoning risk of resistance to existing drugs, has galvanised a new wave of research into anti-microbial drugs. The transfer of knowledge from the Pharmaceutical industry relating to the importance of understanding how to target drugs successfully within the body, and improved understanding of how pathogens interact with their hosts, is driving a series of new paradigms in anti-infective drug design. Here we provide an overview of those processes as an introduction to a series of articles from experts in this area that emerged from a meeting entitled “Emerging Paradigms in Anti-Infective Drug Design” held in London on the 17th and 18th September 2012. The symposium was organised jointly by British Society for Parasitology (BSP) and the Biological & Medicinal Chemistry sector of the Royal Society of Chemistry (RSC) and held at the London School of Hygiene & Tropical Medicine. The symposium set out to cover all aspects of the identification of new therapeutic modalities for the treatment of neglected and tropical diseases. We aimed to bring together leading scientists from all the disciplines working in this field and cover the pharmacology, medicinal chemistry and drug delivery of potential new medicines. Sessions were held on: “Target diseases and targets for drugs”, “Target based medicinal chemistry”, “Bioavailability and chemistry”, “Targeting intracellular microbes”, “Alternative approaches and models”, and “New anti-infectives – how do we get there?”

This symposium was organised by Simon Croft (LSHTM) and Mike Barrett (University of Glasgow) for the BSP, and David Alker (David Alker Associates) and Andrew Stachulski (University of Liverpool) for the Biological & Medicinal Chemistry sector of the RSC.

The microsporidian parasite Thelohania contejeani causes porcelain disease and has been implicated in mass mortalities in populations of the endangered European crayfish Austropotamobius pallipes. However, the route of parasite transmission is not known. This paper investigates the horizontal transmission of T. contejeani between A. pallipes hosts as well as its transmissibility to the invasive signal crayfish (Pacifastacus leniusculus). Field collected juvenile A. pallipes and P. leniusculus were assigned to 1 of 3 experimental treatments; fed heavily infected A. pallipes tissue, exposed to water from tanks housing heavily parasitized A. pallipes, and a control group to provide an estimate of the baseline infection levels in the field. After 26 weeks, abdominal muscle samples were screened by PCR for T. contejeani. Infection was significantly higher in the treatment groups (83% in the cannibalism treatment, 42% in the water exposure treatment) than in the control group (4%), providing evidence for horizontal transmission of the parasite between A. pallipes hosts. Cannibalism and scavenging are common amongst crayfish, providing transmission opportunities in the field. The study also provides the first direct evidence for transmission of the parasite from an indigenous European crayfish species to the invasive signal crayfish, with 50% of P. leniusculus in each treatment, and 8% of control animals infected. We discuss the possibility that high density populations of the invasive signal crayfish may serve either as reservoirs or sinks for the parasite.

Magellanic penguins (Spheniscus magellanicus) are native to Argentina, Chile and the Falkland Islands. Magellanic penguins are highly susceptible to blood parasites such as the mosquito-borne Plasmodium spp., which have been documented causing high morbidity and mortality in zoos and rehabilitation centres. However, to date no blood parasites have been detected in wild Magellanic penguins, and it is not clear whether this is reflective of their true absence or is instead related to an insufficiency in sampling effort or a failure of the diagnostic methods. We examined blood smears of 284 Magellanic penguins from the Argentinean coast and tested their blood samples with nested polymerase chain reaction tests targeting Haemoproteus, Plasmodium, Leucocytozoon and Babesia. No blood parasites were detected. Analysing the sampling effort of previous studies and the climatogeography of the region, we found there is strong basis to conclude that haemosporidians do not infect wild Magellanic penguins on the Argentinean coast. However, at present it is not possible to determine whether such parasites occur on the Chilean coast and at the Falkland Islands. Furthermore, it is troubling that the northward distribution expansion of Magellanic penguins and the poleward distribution shift of vectors may lead to novel opportunities for the transmission of blood parasites.

Psychodiella sergenti is a recently described specific pathogen of the sand fly Phlebotomus sergenti, the main vector of Leishmania tropica. The aim of this study was to examine the life cycle of Ps. sergenti in various developmental stages of the sand fly host. The microscopical methods used include scanning electron microscopy, transmission electron microscopy and light microscopy of native preparations and histological sections stained with periodic acid-Schiff reaction. Psychodiella sergenti oocysts were observed on the chorion of sand fly eggs. In 1st instar larvae, sporozoites were located in the ectoperitrophic space of the intestine. No intracellular stages were found. In 4th instar larvae, Ps. sergenti was mostly located in the ectoperitrophic space of the intestine of the larvae before defecation and in the intestinal lumen of the larvae after defecation. In adults, the parasite was recorded in the body cavity, where the sexual development was triggered by a bloodmeal intake. Psychodiella sergenti has several unique features. It develops sexually exclusively in sand fly females that took a bloodmeal, and its sporozoites bear a distinctive conoid (about 700 nm long), which is more than 4 times longer than conoids of the mosquito gregarines.

An in vitro culture system incorporating a cell monolayer was used to induce most activated oncospheres of Taenia ovis to enter post-oncospheral development. Seven distinct developmental phases were recognized during the 23 days required for development to reach a stage similar to that achieved after 14 days in vivo. Secretions or tegumental substance were released during each developmental phase.

A new species of coccidium E. duodenalis sp.nov., has been described, from the pheasant. It is characterized by the subspherical shape of the oocyst, the lack of polar granules and the presence of large sporocystic residual bodies. Endogenous stages are found in the epithelial cells lining the villi, and occur chiefly in the duodenum and upper intestine. Second-generation merozoites form gametocytes and/or third-generation schizonts. The prepatent period is 5 days.

E. duodenalis is moderately pathogenic, doses of 50 000 oocysts causing a 30% mortality and a significant weight loss in the survivors. Treatment with a range of sulphonamides in the drinking water was successful as was preventive treatment with Sulphaquinoxaline mixed with the food.

Acknowledgements are due to Mr S. F. M. Davies for initiating this programme and carrying out a number of the animal inoculations, to Dr Helen Hein for help and advice in the design of the experiments and to Dr L. P. Joyner for advice in the preparation of the manuscript. The author also wishes to thank Miss C. N. Hebert for the statistical analysis of weight gains and Mr M. A. Peirce, Mr G. L. Choon, Miss J. Saddington and Miss M. Blore for technical assistance.

The advantages and difficulties of various methods employed in the study of larval trematodes are discussed. The desirability of using living specimens rather than fixed material and of studying mature, normally emerged cercariae rather than those obtained by crushing the host is noted. Intra-vitam staining with neutral red is recommended to demonstrate the form and reaction of the secretory granules in gland cells. Knowledge of the details of the excretory system is of major importance in both theoretical and experimental work.

Members of the genus Hepatozoon (Miller, 1908) are blood parasites found in a wide range of host species, including wild rodents; however, information about the life cycle, distribution and Hepatozoon species diversity infecting these mammals are lacking. We studied the parasite stages and DNA sequences of Hepatozoon sp. of 11 naturally infected Akodon montensis. Thin blood smears, tissue samples and whole blood were obtained for morphology, morphometry and molecular analyses. Seven of the 11 rodents had gamonts on the blood smears. Biological and morphological features of the parasite such as tissue tropism, gamonts and meronts size and morphology, as well as the DNA sequence comparison and phylogenetic analysis, indicated that the Hepatozoon sp. detected in this study is distinct from those species previously reported in small rodents. Herein, we propose a new species, named Hepatozoon milleri sp. nov. This is the first description of a new Hepatozoon species from wild small rodents in Brazil, based on morphological and molecular characteristics.

The drug cyclosporin A (CsA) exerts its immunosuppressive action by binding to the cytosolic protein, cyclophilin (CyP) and, as a complex, binding to and inhibiting the calcium/calmodulin-dependent serine threonine phosphatase, calcineurin. It is unknown whether a similar mode of action occurs during the drug's antiparasite activity. Calmodulin-binding proteins from the helminth parasites Hymenolepis microstoma and H. diminuta were purified by affinity chromatography, yielding single polypeptide bands of 60000 Mr, according to SDS–PAGE. These proteins were tested for calcineurin activity by the dephosphorylation of the RII peptide (part of the catalytic subunit of cAMP-dependent protein kinase). Both proteins were calcium- and calmodulin-dependent and were inhibited by mammalian cyclophilin complexed with cyclosporin A (IC50 values of 0·75 μg CyP for H. microstoma and 0·90 μg CyP for H. diminuta). However, neither of the parasite calcineurins was inhibited by H. microstoma cyclophilin/CsA. These data suggest the anthelmintic mode of action of CsA in these helminth models does not involve the inhibition of a signal transduction pathway requiring interaction with calcineurin.

Since the appearance in 1901 of Looss' important monograph on the Sclerostomes of Horses and Donkeys in Egypt a much greater interest has been shown in the presence of these and allied Nematodes in other parts of the world, but, although nearly fifteen years have elapsed since that publication, very little addition has been made to our knowledge of this branch of helminthology

The susceptibility to oxidant-mediated killing of Plasmodium falciparum infecting normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes was assessed by exposure to hydrogen peroxide generated by the glucose–glucose oxidase system. The parasites infecting G6PD-deficient erythrocytes had markedly greater susceptibility to hydrogen peroxide under a variety of conditions than those infecting normal erythrocytes. In both cases, the killing effect was mediated mainly through the host cells since treatment of the erythrocytes with hydrogen peroxide did not change their relative susceptibility. The parasites were most susceptible during maturation, especially in G6PD-deficient erythrocytes, although a reduction in parasite invasion was also observed. The role of oxidant-mediated killing in the protection of G6PD-deficient hosts from P. falciparum infection is discussed.

In 1908 intestinal parasites of man were described by Bohne and Prowazek. The authors considered them to be cysts of Trichomonas hominis. The parasites consist of a highly refractile spherical body, staining yellow or yellowish brown with iodine and pale grey or black with iron haematoxylin; this sphere is surrounded by a narrow plasmatic layer, containing the nuclei. Bensen (1910) gave a detailed description of these bodies, with stages of autogamy, and considered them also to be cysts of Trichomonas. Prowazek (1911) did not subsequently change his opinion regarding the systematic position of these bodies and James (1914) confirmed Prowazek's views by stating that cats infected with the same bodies showed Trichomonas in their stools.

Electrophysiological techniques and behavioural assays were used to determine the response of males of Globodera rostochiensis to 4 fractions of the homospecific sex pheromone from virgin females, separated using reverse-phase high-pressure liquid chromatography. Sex pheromone activity was confined to 2 of the fractions. The sex pheromone of G. rostochiensis appears to be composed of several weakly basic, polar compounds.

The life history of Onesia accepta Mall. is described. This species is parasitic on the earthworm Microscolex dubius Fletcher. The first and second larval instars are passed under the skin and the third instar in the body cavity of the host. The feeding period of the maggot is approximately 20 days, and the pupal stage about 12 days.

The external morphology of the three larval instars and of the puparium is described in detail.