Climate and weather conditions may have substantial effects on the ecology of both parasites and hosts in natural populations. The strength and shape of the effects of weather on parasites and hosts are likely to change as global warming affects local climate. These changes may in turn alter fundamental elements of parasite–host dynamics. We explored the influence of temperature and precipitation on parasite prevalence in a metapopulation of avian hosts in northern Norway. We also investigated if annual change in parasite prevalence was related to winter climate, as described by the North Atlantic Oscillation (NAO). We found that parasite prevalence increased with temperature within-years and decreased slightly with increasing precipitation. We also found that a mild winter (positive winter NAO index) was associated with higher mean parasite prevalence the following year. Our results indicate that both local and large scale weather conditions may affect the proportion of hosts that become infected by parasites in natural populations. Understanding the effect of climate and weather on parasite–host relationships in natural populations is vital in order to predict the full consequence of global warming.

The African penguin (Spheniscus demersus) is a critically endangered species endemic to southern Africa. Limited information is available on the parasite diversity associated with the species in natural settings. This study explores the diversity and incidence of parasites associated with African penguins and their nests, and records the effect of host and environmental factors on parasite infestation. Ecto-, haemo- and helminth parasites were recorded from 210 adult birds, 583 chicks and 628 nests across five colonies (two mainland and three islands) along the south-western coast of South Africa, in 2016 and 2017. Mean nest density (total and active nests) and climate variables (temperature and precipitation) were obtained for each colony. Parapsyllus humboldti was the most abundant and prevalent ectoparasite on penguins and in nests (69.10 and 57.80%, respectively), while Piroplasmorida/Haemospororida (33.51%) and Cardiocephaloides spp. (56.17%) were the most prevalent haemo- and helminth parasites of penguins, respectively. In general parasite abundance and prevalence was significantly affected by penguin age (chicks vs adults), location (mainland vs islands), nest density (total and active nests) and season (spring vs autumn/winter). It is concluded that parasite infestations are structured and that penguin chicks at mainland colonies are more susceptible to parasite infestations during spring.

Data on 279 species of trematodes of birds and mammals are analysed in tables, to show the molluscan orders and families that act as first intermediate hosts of various trematode families.

Host-specificity is highly developed in the first larvae of trematodes and it is suggested that, as a consequence of this, certain species, genera and families of molluscs harbour a greater variety of trematodes than others. The families Lymnaeidae, Physidae, Planorbidae, Hydrobiidae and Thiaridae are by far the most important first-intermediate hosts of the trematodes of birds and mammals whose life cycles are known; each family acting as host of not less than twenty-four species and eight families of trematodes.

This paper is published with the approval of the Director General of Health, Canberra, A.C.T.

Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus including species seldom investigated in sub-Saharan Africa. We surveyed wild small mammal populations in the areas of Richard Toll and Lake Guiers, Senegal, with the objective to evaluate their potential role as intermediate hosts of larval taeniid stages (i.e. metacestodes). Based on genetic sequences of a segment of the mitochondrial DNA gene cytochrome c oxidase subunit 1 (COI), we identified Hydatigera parva metacestodes in 19 out of 172 (11.0%) Hubert's multimammate mice (Mastomys huberti) and one out of six (16.7%) gerbils (Taterillus sp.) and Hydatigera taeniaeformis sensu stricto metacestodes in one out of 215 (0.5%) Nile rats (Arvicanthis niloticus). This study reports epidemiological and molecular information on H. parva and H. taeniaeformis in West African rodents, further supporting the phylogeographic hypothesis on the African origin of H. parva. Our findings may indicate significant trophic interactions contributing to the local transmission of Hydatigera spp. and other parasites with similar life-cycle mechanisms. We therefore propose that further field investigations of rodent population dynamics and rodent-borne infectious organisms are necessary to improve our understanding of host–parasite associations driving the transmission risks of rodent parasites in West Africa.

A survey in Busoga District, Uganda, where an outbreak of sleeping sickness was detected, has yielded an infection rate with T. brucei subgroup in G. fuscipes of 4.8%. Isolation of the infected flies was by feeding of the flies on mice, followed by trituration and inoculation of a suspension of the triturated flies into mice. The mice were treated with cyclophosphamide to reduce the immune response.The percentage infection as determined by inoculation of triturate was 4.1%, whilst that by feeding on mice was 1–8%.Amongst the 19 strains of T. brucei subgroup isolated, four were identified as T. rhodesiense by the BIIT method.

The transport of [14C]glucose by Hymenolepis microstoma in vitro following in vivo treatment with cyclosporin A (CsA) was determined over a range of concentrations. For untreated (control) worms glucose uptake showed saturation kinetics with a small diffusion component. Estimates of the maximum velocity of glucose uptake (Vmax) and the affinity of substrate for the glucose transporter (Kt) revealed that untreated 8-day-old worms had a Vmax twice that of 15-day-old worms and that younger worms had a lower Kt. An inverse relationship was demonstrated between log10 worm weight and the rate of uptake of [14C]glucose, reflecting the relatively greater number of glucose transporters due to the larger surface area: volume ratio of smaller worms. Treatment of H. microstoma with CsA in vivo significantly increased the diffusion component of glucose uptake in vitro. Parasites from drug-treated mice had a significantly lower Vmax for glucose uptake than size-matched controls. The affinity of glucose for its transporter in CsA-treated worms (Kt) was not significantly different from size-matched controls. Both juvenile and adult worms underwent transient depletion in total glycogen content after CsA treatment in vivo. The data confirm that CsA treatment in vivo disrupts the functional integrity of the worm tegument, one facet of which is impaired acquisition of glucose.

Host suitability, reproduction, effects of temperature on reproduction and pupal development, effects of humidity on pupal development and the effects of photoperoid on puparial deposition, pupal development and adult emergence were studied in a laboratory colony of Pseudolynchia canariensis. Flies were observed to lack strong host specificity. Puparia were produced at regular 24 h intervals by flies maintained at 30 °C, averaging 8·8 puparia per female. Optimum temperature for colony maintenance was observed to range between 26·6 and 30·0 °C. Temperatures of 13 and 37 °C were lethal to pupae. Humidity and photoperiod did not markedly affect pupal development. Puparial deposition and adult emergence occurred only during the photoperiod.

An earlier mathematical model exploring the use of genetically manipulated mosquitoes for malaria control suggested that the prevalence of malaria is reduced significantly only if almost all mosquitoes become completely resistant to malaria. Central to the model was the ‘cost of resistance’: the reduction of a resistant mosquito's evolutionary fitness in comparison with a sensitive one's. Here, we consider the possibility of obtaining more optimistic outcomes by taking into account the epidemiological (in addition to the evolutionary) consequences of a cost of resistance that decreases the life-span of adult mosquitoes (the most relevant parameter for the parasite's epidemiology). There are two main results. First, if despite its cost, resistance is fixed in the population, increasing the cost of resistance decreases the intensity of transmission. However, this epidemiological effect is weak if resistance is effective enough to be considered relevant for control. Second, if the cost of resistance prevents its fixation, increasing it intensifies transmission. Thus, the epidemiological effect of the cost of resistance cannot compensate for the lower frequency of resistant mosquitoes in the population. Overall, our conclusion remains pessimistic: so that genetic manipulation can become a promising method of malaria control, we need techniques that enable almost all mosquitoes to be almost completely resistant to infection.

1. The shell gland of Fasciola hepatica produces an extremely hyaline secretion. The egg-shell is formed from the hyaline secretion.

2. As the eggs travel through the uterus, the shell is temporarily reinforced from the inside by vitelline granules. The vitelline granules are released when the vitelline cells enter the vitelline reservoir.

3. Views regarding the nomenclature of the shell gland are discussed.

4. The presence of an elliptical chamber in the shell gland is described. In this chamber, oocytes, vitelline granules and vitelline cells are mixed together, and here the secretion of the shell gland is released and the egg-shell is formed.

5. The arrangement of the cellular constituents within the egg is effected by the elliptical chamber.

Cells of six isolates of Trypanosoma lewisi from the United States, England, Puerto Rico, Costa Rica, and Singapore were matched against antiserum to the ‘L’ isolate in microagglutinin chambers. Antisera were prepared in Sprague-Dawley rats. Serum protein determinations were made by the biuret reaction; electrophoretic fractionations of serum proteins were done with a semi-closed horizontal system (Evans & Stirewalt, 1947) at 4°C for 24 h, 120 V, and 8 mA with paper strips. Electrolyte was veronal buffer, pH 8·6 and μ 0·058. Agglutinin absorptions were carried out using inactivated anti-‘L’ sera.

Total protein (mg/ml) values were higher in all infected animals (60 vs. 54). Albumin values (%) were higher in controls (47 vs. 40);α-1 fractions were essentially unchanged (15%) as were α-2 values (6%). β Fractions were elevated in infected groups (21 vs. 17%), as were the γ globulins (19 vs. 12%).

Three protocols employing agglutinin reactions were completed. In two protocols 3+ agglutinin end-points were obtained with four isolates using 1·45–1·47 μg of immune γ globulin. Two of the isolates (Puerto Rico and Singapore) required 10 times this amount of immune globulin for the same end-point. In two other tests all isolates gave reaction end-points that required greater quantities (by a factor of ca. 500) of immune γ globulin than obtained in the first two tests, and there was further evidence that the Costa Rican isolate was quantitatively different from the others. These facts are interpreted to mean that all six geographic isolates show close qualitative relationships to each other, but that the relationships for the Puerto Rican, Singapore and Costa Rican isolates are quantitatively different. Agglutinins could not be absorbed from immune serum by any of the cells.

When examining the contents of the alimentary canal of caddis-fly larvae, I found that in addition to certain well-known gregarines, they generally harbour several other interesting protist parasites which have not hitherto been described. Chief among these are: (a) a tricho-mastix, (b) a spirochaete, and (c) a flagellate which appears to be related to Macrostoma caulleryi, Alexieff. The present paper deals with the trichomastix and the spirochaete: I hope to describe the other flagellate fully in a future communication.

An activity cell apparatus to facilitate quantitative measurements of motility of small nematodes in saline is described. The effects of salines with a pO2 either greater than 120 mmHg or less than 12 mmHg upon the motility of adult N. brasiliensis females was studied. The worms were found to require an oxygen tension greater than 12 mmHg to be able to maintain their motility.

I am grateful to Professors J. Brough and D. Bellamy for providing the facilities during the course of this study. I should also like to thank Dr R. A.Hammond for his supervision, help and criticism throughout the project, and Mr C. Welsby for his technical assistance in the construction of the activity cell.

This work was carried out during the tenure of a Scientific Research Council Studentship.

Alveolar echinococcosis is a neglected parasitic zoonosis caused by the metacestode Echinococcus multilocularis, which grows as a malignant tumour-like infection in the liver of humans. Albendazole (ABZ) is the antiparasitic drug of choice for the treatment of the disease. However, its effectiveness is low, due to its poor absorption from the gastro-intestinal tract. It is also parasitostatic and in some cases produces side-effects. Therefore, an alternative to the treatment of this severe human disease is necessary. In this context, the repositioning of drugs combined with nanotechnology to improve the bioavailability of drugs emerges as a useful, fast and inexpensive tool for the treatment of neglected diseases. The in vitro and in vivo efficacy of dichlorophen (DCP), an antiparasitic agent for intestinal parasites, and silica nanoparticles modified with DCP (NP-DCP) was evaluated against E. multilocularis larval stage. Both formulations showed a time and dose-dependent in vitro effect against protoscoleces. The NP-DCP had a greater in vitro efficacy than the drug alone or ABZ. In vivo studies demonstrated that the NP-DCP (4 mg kg−1) had similar efficacy to ABZ (25 mg kg−1) and greater activity than the free DCP. Therefore, the repurposing of DCP combined with silica nanoparticles could be an alternative for the treatment of echinococcosis.

Setaria cervi, a bovine filarial parasite contains significant acid phosphatase (AcP) activity in its various life stages. Two forms of AcP were separated from somatic extract of adult female parasite using cation exchange, gel filtration and concavalin affinity chromatography. One form having a molecular mass of 79 kDa was characterized as dual specific protein tyrosine phosphatase (ScDSP) based on substrate specificity and inhibition studies. With various substrates tested, it showed significant activity in the order of phospho-L-tyrosine>pNPP>ADP>phospho-L-serine. Inhibition by orthovanadate, fluoride, molybdate, and zinc ions further confirms protein tyrosine phosphatase nature of the enzyme. Km and Vmax determined with various substrates were found to be 16·66 mM, 25·0 μM/ml/min with pNPP; 20·0 mM, 40·0 μM/ml/min with phospho-L-tyrosine and 27·0 mM, 25·0 μM/ml/min with phospho-L-serine. KI with pNPP and sodium orthovanadate (IC50 33·0 μM) was calculated to be 50·0 mM. Inhibition with pHMB, silver nitrate, DEPC and EDAC suggested the presence of cysteine, histidine and carboxylate residues at its active site. Cross-reactivity with W. bancrofti-infected sera was demonstrated by Western blotting. ScDSP showed elevated levels of IgE in chronic filarial sera using ELISA. Under in vitro conditions, ScDSP resulted in increased effector function of human eosinophils when stimulated by IgG, which showed a further decrease with increasing enzyme concentration. Results presented here suggest that S. cervi DSP should be further studied to determine its role in pathogenesis and the persistence of filarial parasite.

Artyfechinostomum Lane, 1915 (type A. sufrartyfex Lane, 1915) is a synonym of Paryphostomum Dietz, 1909 (type P. radiatum Dujardin, 1845). While the general morphology of the two forms is similar and places them both in the family Echinostomatidae, other characters clearly place them in different genera of this family. In Artyfechinostomum the cirrus-sac extends far posterior to the acetabulum, and the right and left fields of vitellaria in the post-testicular region are confluent. In Paryphostomum the cirrus-sac is small and anterior to the middle of the acetabulum and the vitellaria in the post-testicular region are not confluent. These differences entitle Artyfechinostomum to be placed in a separate genus. The species Paryphostomum indicum Bhalerao, 1931 and P. mehrai Jain, 1957 are transferred to the genus Artyfechinostomum.

The localization and distribution of SALMFamide immunoreactivity (IR), SI(GFNSALMFamide), in the nervous system of both the adult and larval stages of the trematode Schistosoma mansoni has been determined by an indirect immunofluorescent technique in conjunction with confocal scanning laser microscopy (CSLM). Immunostaining was widespread in the nervous system of adult male and female S. mansoni. In the central nervous system (CNS), IR was evident in nerve cells and fibres in the anterior ganglia, cerebral commissure and dorsal and ventral nerve cords. In the peripheral nervous system (PNS), IR was apparent in nerve plexuses associated with the subtegmental musculature, oral and ventral suckers, the lining of the gynaecophoric canal, and in fine nerve fibres innervating the dorsal tubercles of the male worm. In the reproductive system of male and female worms, Sl-IR was only observed around the ootype/Mehlis' gland complex in the female. Immunostaining was also evident in the nervous system of both miracidium and cercarial larval stages. A post-embedding, IgG-conjugated colloidal gold immunostaining technique was employed to examine the subcellular distribution of SALMFamide-IR in the CNS of S. mansoni. Gold labelling of peptide was localized over dense-cored vesicles within nerve cell bodies and fibres constituting the neuropile of the anterior ganglia, cerebral commissure and nerve cords of the CNS. Antigen pre-absorption studies indicated that the results obtained do suggest S1-like immunostaining and not cross-reactivity with other peptides, in particular FMRFamide.

Four new actinospore types belonging to the sphaeractinomyxon collective group (Cnidaria, Myxosporea) are described from the coelomic cavity of a marine Baltidrilus sp. (Oligochaeta, Naididae) inhabiting a northern Portuguese estuary. Host identification supports the usage of marine oligochaetes, namely of the family Naididae Ehrenberg, 1828, as definitive hosts for myxosporeans inhabiting estuarine/marine environments. The absence of mixed infections in the host specimens analysed is suggested to reflect the influence of host-, parasite- and environmental-related factors regulating myxosporean–annelid interactions. Molecular analyses matched the SSU rDNA sequences of three of the four new types with those of mugiliform-infecting Myxobolus spp., namely Myxobolus mugiliensis and a Myxobolus sp. from flathead grey mullet Mugil cephalus, and Myxobolus labrosus from thicklip grey mullet Chelon labrosus. These results directly link, for the first time, the sphaeractinomyxon collective group to a myxospore counterpart, further confirming their previously hypothesized specific involvement in the life cycle of myxobolids that infect mullets. Acknowledging this life cycle relationship, the functionality of the sphaeractinomyxon morphotype is suggested to have been decisive for the evolutionary hyperdiversification of the genus Myxobolus in mullets. Unlike other actinospore morphotypes, sphaeractinomyxon lack valvular processes, which implies a limited capability for buoyancy. Considering the benthic-feeding nature of mullets, this feature is most likely crucial in promoting successful transmission to the vertebrate host.

In a recent study by our group on the prevalence of intestinal parasitic infections and on the knowledge, attitudes and practices of local residents of Campos dos Goytacazes, Rio de Janeiro, Brazil, we observed that about 50% of the inhabitants were parasitized and had some knowledge of intestinal parasitic infections but did not apply this knowledge in daily practice. We were thus motivated to implement strategies in health education to promote preventive measures in the locality. The goal of the present work was to evaluate the influence of health education on the prevalence of intestinal parasitic infections in the region in an effort to strengthen public policies for controlling these diseases in Brazil. The methodology adopted was based on action-research and a theoretical framework of health promotion. Our results demonstrate that the study population exhibited an enhanced awareness of the importance of disease from intestinal parasitic infections. Attitudes and practices related to prevention were significantly improved after the shared health education. In conclusion, this study allowed the shared construction of knowledge that reflected the true needs of the residents.

The longevity of filarial nematodes is dependent on secreted immunomodulatory products. Previous investigation of one such product, ES-62, has suggested a critical role for post-translationally attached phosphorylcholine (PC) moieties. In order to further investigate this, ES-62 lacking PC was produced, using the Pichia pastoris recombinant gene expression system. Unlike parasite-derived ES-62, which is tetrameric the recombinant material was found to consist of a mixture of apparently stable tetramers, dimers and monomers. Nevertheless, the recombinant protein was considered to be an adequate PC-free ES-62 as it was recognized by existing antisera against the parasite-derived protein. However, subsequent to this, recognition of parasite-derived ES-62 by antibodies produced against the recombinant protein was found to be absent. In an attempt to explain this, recombinant ES-62 was subjected to structural analysis and was found to (i) contain 3 changes in amino acid composition; (ii) demonstrate significant alterations in glycosylation; (iii) show major differences in protein secondary structure. The effects of these alterations in relation to the observed change in immunogenicity were investigated and are discussed. The data presented clearly show that recognition by existing antibodies is insufficient proof that recombinant proteins can be used to mimic parasite-derived material in studies on nematode immunology and vaccination.

The aim of the present investigation was to determine whether temporal variation in environmental factors such as rainfall or temperature influence long-term fluctuations in the prevalence and mean abundance of the nematode Mexiconema cichlasomae in the cichlid fish Cichlasoma uropthalmus and its crustacean intermediate host, Argulus yucatanus. The study was undertaken in a tropical coastal lagoon in the Yucatan Peninsula (south-eastern Mexico) over an 8-year period. Variations in temperature, rainfall and monthly infection levels for both hosts were analysed using time series and cross-correlations to detect possible recurrent patterns. Infections of M. cichlasomae in A. yucatanus showed annual peaks, while in C. urophthalmus peaks were bi-annual. The latter appear to be related to the accumulation of several generations of this nematode in C. urophthalmus. Rainfall and temperature appear to be key environmental factors in influencing temporal variation in the infection of M. cichlasomae over periods longer than a year together with the accumulation of larval stages throughout time.