Leishmaniasis development is multifactorial; nonetheless, the establishment of the infection, which occurs by the survival and replication of the parasite inside its main host cell, the macrophage, is mandatory. Thus, the importance of studying the molecular mechanisms involved in the Leishmania–macrophage interaction is highlighted. The aim of this study was to characterize a cellular model of macrophages derived from U937 cells that would allow for the identification of infection phenotypes induced by genetic silencing with interference RNA in the context of macrophages infected with Leishmania (Viannia) braziliensis. The model was standardized by silencing an exogenous gene (gfp), an endogenous gene (lmna) and a differentially expressed gene between infected and non-infected macrophages (gro-β). The silencing process was successful for the three genes studied, obtaining reductions of 88·9% in the GFP levels, 87·5% in LMNA levels and 74·4% for Gro-β with respect to the corresponding control cell lines. The cell model revealed changes in the infection phenotype of the macrophages in terms of number of amastigotes per infected macrophage, number of amastigotes per sampled macrophage and percentage of infected macrophages as a result of gene silencing. Thus, this cell model constitutes a research platform for the study of parasite–host interactions and for the identification of potentially therapeutic targets.

Robert Leiper is best known for his discoveries in the fields of Guinea worm and schistosomiasis, but he also made major contributions to parasitology during his career as helminthologist and later Professor of Helminthology at the London School of (Hygiene and) Tropical Medicine. He was particularly involved in establishing the London School's Winches Farm Field Station and stimulating the research carried out there, work that has made a number of important contributions to our understanding of parasites. Leiper founded the Commonwealth Bureau of Agricultural Parasitology and was also instrumental in initiating, and editing, the Journal of Helminthology, Helminthological Abstracts and establishing, indirectly, Protozoological Abstracts.

A comparative analysis has been made of the efficacy of different chemotherapeutic schemes against hookworm infections in China. Hookworm eggs were detected by the improved Kato's thick smear method. Benzimidazole was offered to residents in the tested villages, while NaHCO3 was used as placebo in control villages. Data were analysed by negative binomial distribution with statistic software R2.2.1. In the tested village as a result of the application of selective chemotherapy, hookworm infection rate decreased from 58·79% to 1·08%, while the average of eggs per gram (EPG) reduced from 526·29 to 56·91. The infection rates in the target chemotherapy village and in the mass chemotherapy village declined from 6·90% to 1·92% and 10·10% to 0·65% respectively. It was concluded that the consecutive selective chemotherapy could rapidly decrease the infection rate and EPG of hookworm and maintain the infection rate at low level. The curative effect of the target chemotherapy was similar to that of the mass chemotherapy in the low hookworm endemic area.

In vitro maintenance of helminth parasites enables a variety of molecular, pharmaceutical and immunological analyses. Currently, the nutritional and environmental in vitro requirements of the equine ascarid parasite, Parascaris spp., have not been determined. Additionally, an objective method for assessing viability of Parascaris spp. intestinal stages does not exist. The purpose of this study was to ascertain the in vitro requirements of intestinal stages of Parascaris spp., and to develop a viability assessment method. A total of 1045 worms were maintained in a total of 212 cultures. Worms obtained from naturally infected foals at necropsy were immediately placed in culture flasks containing 200 mL of culture media. A variety of media types, nutrient supplementation and environmental conditions were examined. A motility-based scoring system was used to assess worm viability. Worms maintained in Roswell Park Memorial Institute-1640 had significantly better viability than any other media (P < 0.0001) and all media types supplemented with any of the nutrients examined (P < 0.0001). The use of a platform rocker also significantly improved viability (P = 0.0305). This is the first study to examine the requirements for maintaining Parascaris spp. intestinal stages in vitro and to evaluate their viability based on movement using an objective scoring system.

Fibres isolated from the ventral sucker of Fasciola hepatica were identified as muscle on the basis of their contractility, and their actin and myosin staining. They were voltage-clamped at a holding potential of −40 mV and depolarization-activated outward currents were characterized both electrophysiologically and pharmacologically. Activation was well fitted by a Boltzmann equation with a half-maximal potential of +9 mV and a slope factor of −14·3 mV, and the kinetics of activation and deactivation were voltage-sensitive. Tail current analysis showed that the reversal potential was shifted by +46±3 mV when EK was increased by 52 mV, confirming that this was a K+-current with electrophysiological characteristics similar to delayed rectifier and Ca2+-activated K+-currents in other tissues. The peak current at +60 mV was inhibited by 76±6% by tetrapentylammonium chloride (1 mM) and by 84±7% by Ba2+ (3 mM), but was completely resistant to block by tetraethylammonium (30 mM), 3,4-diaminopyridine (100 μM) and 4-aminopyridine (10 mM). Penitrem A, a blocker of high-conductance Ca2+-activated K+-channels reduced the current at +60 mV by 23±5%. When the effects of Ca2+-channel blocking agents were tested, the peak outward current at +60 mV was reduced by 71±7% by verapamil (30 μM) and by 59±4% by nimodipine (30 μM). Superfusion with BAPTA-AM (50 μM), which is hydrolysed intracellularly to release the Ca2+-buffer BAPTA, also decreased the current by 44±16%. We conclude that voltage-and Ca2+-sensitive K+-channels are expressed in this tissue, but that their pharmacology differs considerably from equivalent channels in other phyla.

In this investigation, the host–parasite relationship of ninespine stickleback fish Pungitius pungitius and the cestode parasite Schistocephalus pungitii was studied using samples from Dog Bone Lake, Kenai Peninsula, Alaska, to test the hypothesis that S. pungitii is a castrator of ninespine stickleback. Infected, adult females of all sizes (ages) were capable of producing clutches of eggs. S. pungitii had a negative effect on the ability of host females to produce a clutch, which was related to increasing parasite:host mass ratio (parasite index, PI). Among infected females with egg clutches, both clutch size and egg size were reduced; and the reduction increased with greater PI. The results of this study are consistent with the hypothesis that S. pungitii causes host sterility as a result of simple nutrient theft and is not a true castrator as hypothesized in earlier reports. The degree of parasite-induced sterility appears to vary among populations of the ninespine stickleback, perhaps reflecting differences in resource availability. Populations of ninespine stickleback appear to show a greater reduction in host reproductive capacity with PI than populations of the threespine stickleback infected by Schistocephalus solidus, possibly owing, in part, to the length-adjusted somatic mass of the threespine stickleback being greater.

This worm was obtained from the intestine of Sarcogrammus indicus Stoliczka at Nagpur, C.P., India. It was flattened out between two glass slides, fixed in Mann's fluid and stained with Delafield's haematoxylin. The measurements of the worm given in the following description relate to the flattened specimen.

1. Axenic strains of Entamoeba invadens can be maintained indefinitely, by serial culture, in saline containing a slice of liver. Growth in this medium is poor, the amoebae are vacuolated, and few cysts are formed.

2. The optimum concentration of NaCl for amoebic growth in this medium is 0·75–1·0%, and the optimum pH is 5·7–6·1.

3. The source of the liver tissue in the medium is unimportant, but, of several tissues tested, liver was the only one which supported amoebic growth in serial culture.

4. Suspensions of minced liver also supported amoebic growth, but the growth-promoting activity of the liver was removed completely by centrifugation, autoclaving, and Seitz- or glass-filtration. Heat treatment at 50–60° C. and prolonged storage at 8° C. partially inactivated the liver.

5. Growth in axenic saline-liver medium does not affect the ability of E. invadens to grow and undergo mass encystation when reassociated with suitable bacteria.

During investigations at the Bussey Institution on the rôle played by certain dipterous larvae in experimentally induced myiasis, with the object if possible of clearing a little of the doubt with which so much of the question is shrouded, the need of good diagnostic characters for these larvae was brought forcibly to my attention.

The priority of the names of the fishes in the following list has been determined from Jordan in Part II of the Report of the United States Commissioner of Fisheries for the year 1928: A check list of Fishes. In determining the names of those not mentioned in this list I have to thank Mr J. R. Norman of the British Museum for his kind assistance.

Through the kindness of H. H. Woken, the veterinary surgeon of the Zoological Garden in Leningrad, we were able to examine the faeces of two species of birds—the grey partridge (Perdix perdix) and the stone partridge (Caccabis chucar). It is very probable that the coccidian found by us is common to both species of birds, but as they were kept in the same cage it was not possible to determine the origin of the faeces examined.

The comparative resistance to high temperature and various humidities of four species of blow-flies, Calliphora erythrocephala Meig., Lucilia sericata Meig., Sarcophaga falculata Pand. and Phormia groenlandica Zett. is studied. It is shown that Phormia groenlandica is the most resistant species and Calliphora erythrocephala the least resistant species, with Lucilia sericata and Sarcophaga falculata occypying an intermediate position.

This order of resistance is correlated negatively with the order of the seasonal succession of the species.

It is suggested that certain differences in the length of life of males and females subjected to various humidities is brought about by an “ageing” factor.

Vitamin D has been reported to activate macrophage microbicidal mechanisms by inducing the production of antimicrobial peptides and nitric oxide (NO), but conversely has been shown to contribute to a greater susceptibility to Leishmania amazonensis infection in mice. Thus, this study aimed to evaluate the role of vitamin D during intracellular infection with L. amazonensis by examining its effect on macrophage oxidative mechanisms and parasite survival in vitro. Vitamins D2 and D3 significantly inhibited promastigote and amastigote growth in vitro. Vitamin D3 was not able to induce NO and reactive oxygen species (ROS) production in uninfected macrophages or macrophages infected with L. amazonensis. In addition, vitamin D3 in combination with interferon (IFN)-γ did not enhance amastigote killing and in fact, significantly reduced NO and ROS production when compared with the effect of IFN-γ alone. In this study, we demonstrated that vitamin D directly reduces parasite growth in infected macrophages (approximately 50–60% at 50 μm) but this effect is independent of the activation of macrophage oxidative mechanisms. These findings will contribute to a better understanding of the role of vitamin D in cutaneous leishmaniasis.

Filarial nematodes possess glutathione transferases (GSTs), ubiquitous enzymes with the potential to detoxify xenobiotic and endogenous substrates, and modulate the host immune system, which may aid worm infection establishment, maintenance and survival in the host. Here we have identified and characterized a σ class glycosylated GST (OoGST1), from the cattle-infective filarial nematode Onchocerca ochengi, which is homologous (99% amino acid identity) with an immunodominant GST and potential vaccine candidate from the human parasite, O. volvulus, (OvGST1b). Onchocerca ochengi native GSTs were purified using a two-step affinity chromatography approach, resolved by 2D and 1D SDS-PAGE and subjected to enzymic deglycosylation revealing the existence of at least four glycoforms. A combination of lectin-blotting and mass spectrometry (MS) analyses of the released N-glycans indicated that OoGST1 contained mainly oligomannose Man5GlcNAc2 structure, but also hybrid- and larger oligommanose-type glycans in a lower proportion. Furthermore, purified OoGST1 showed prostaglandin synthase activity as confirmed by Liquid Chromatography (LC)/MS following a coupled-enzyme assay. This is only the second reported and characterized glycosylated GST and our study highlights its potential role in host-parasite interactions and use in the study of human onchocerciasis.

This work introduces new morphological and molecular information on the filaroid nematode Setaria cervi (Rudolphi, 1819) obtained from 13 infected game ungulates out of 96 dissected. The hosts comprised the following: a single moose (Alces alces), ten red deer (Cervus elaphus) and two sika deer (Cervus nippon) originating from the western and northern regions of the Czech Republic. Based on the complete sequences of the gene encoding mitochondrial cytochrome c oxidase subunit 1 (cox1), all 20 females and four males belonged to the species S. cervi. We detected three developmental female stages (adult fertile females, juvenile L5 females and L4 female larvae) differing in size and some morphological traits as the subtle structure of peribuccal crown and shape and features of tail knob. Such differences were described in detail for the first time. The phylogenetic relationships within the family Onchocercidae have been evaluated using new information on the cox1 sequence of S. cervi (maximum likelihood method, GTR + I + G model). In accordance with the latest phylogenetic studies, the present analysis confirmed the ancient separation of the subclass Setariinae from the remaining two onchocercid lineages Dirofilariinae and Onchocerinae.

On March 7th, 1931, the writer collected numerous ticks (six species) from an adult tapir, Tapirella, bairdii (Gill), soon after it had been killed near Summit, Canal Zone, Isthmus of Panama. By far the greater number belonged to a species somewhat resembling Amblyomma cajennense in general appearance, but showing characteristics readily separating it from that species. Two young tapirs, of the same species as the foregoing, that were examined more recently were also found to be heavily infested with this species of tick. Since this species is apparently a new one it is herewith described under the name of Amblyomma tapirellum.