There has recently been published a series of observations, based on experimental evidence, which goes to show that the course of an helmintic infestation may be significantly affected by the diet which is fed to the experimental animal. These results which have emanated mainly from Ackert and his colleagues (1929 and 1931) and from Foster & Cort (1931 and 1932), Hiraishi (1927 and 1928) and from Nagoya (1931) show that the vitamins are frequently significant factors affecting the development of Ascaridia, hookworms and Ascaris. In a later paper (1933), Ackert and others showed further that the type of amino-acids and the variety may also be factors influencing the development of Ascaridia lineata in chickens.

The investigations described in this paper are in part a continuation of those described by Carroll and McMahon in a previous paper published in 1935. The previous paper demonstrated the fact that the root excretion of potatoes growing in recently sterilized soil does not possess the power of inducing the hatching of eelworm eggs in the normal manner. It was shown that when eelworm cysts were placed in soil leaching (containing potato root excretion) obtained from pots of very recently sterilized soil growing potatoes practically no hatch of the eggs in these cysts took place until after the lapse of about thirty days. It was further indicated that this interval of time which elapses before hatching commences diminishes according as the period between time of sterilization of the soil and time of obtaining soil leaching for hatching experiment increases.

1. An investigation of the helminth parasites of the African Darter, Anhinga rufa rufa in Ghana produced the following trematodes and cestodes:

(1) Strigea anhingae n.sp.

(2) Diplostomum ghanense n.sp.

(3) Phagicola bulbosa n.sp.

(4) Clinostomum tilafiiae Ukoli, 1966

(5) Clinostomum phalacrocoracis Dubois, 1931

(6) Echinorhynchotaenia tritesticulata Fuhrmann, 1909

The new species are described and classified in this paper.

The nematode Teladorsagiacircumcincta is a major cause of parasitic gastroenteritis in sheep in temperate regions. The development of resistance to the major anthelmintic classes used for its control is a threat to small ruminant farming sustainability. Vaccination is a potential alternative control method for this nematode. Gene datasets can be exploited to identify potential vaccine candidates and these validated further by methods such as RNA interference (RNAi) prior to vaccine trials. Previous reports indicate that RNAi in parasitic nematodes is inconsistent and, to date, there are no internal controls that indicate activation of the RNAi pathway in response to double-stranded RNA (dsRNA). The present aims were to determine whether or not the transcription levels of potential marker genes in the RNAi pathway could indicate activation of the pathway in Caenorhabditis elegans and to develop an RNAi platform in T. circumcincta. In C. elegans, transcript levels of three candidate marker genes, Ce-dcr-1 (Dicer), Ce-ego-1 (Enhancer of Glp-One family member) and Ce-rsd-3 (RNAi Spreading Defective), were analysed and results indicated that activation of the pathway had no effect on transcript levels of these genes. In T. circumcincta, two vaccine candidate genes from the Activation-associated Secreted Protein (ASP) family were targets for knockdown. RNAi experiments showed successful silencing of both targets, although inconsistencies in efficacy were observed. After testing a number of parameters that might affect variability, it was found that the length of the storage period of the larvae plays an important role in the consistency of the RNAi results.

In central Mexico, populations of the freshwater snail Physella cubensis were infected with metacercariae from a species of Echinoparyphium (Digenea: Echinostomatidae). In the current study, we describe both larval and adult stages of this species obtained from experimental and natural infections. A total 180 snails were collected from Patzcuaro Lake, Michoacan state in central Mexico in July 2012. In the laboratory snails were placed in individual vials and exposed to light with the aim of observing emergence of cercariae. To obtain metacercariae, uninfected snails (P. cubensis) were exposed to cercariae. Chicks were infected with metacercariae to obtain adults. Nine days post-infection, eggs were recovered and incubated in tap water at room temperature to observe miracidia. Adults obtained from natural and experimentally infected hosts possess a head collar with 45 spines in two alternating rows, confirming the identification as Echinoparyphium recurvatum von Linstow 1873. To test the conspecificity of all stages, sequences of nuclear internal transcribed spacer 1 (ITS1), 5.8S and ITS2 rDNA were obtained from two adult worms recovered from chicks and also a natural avian host, the shoveler duck Anas clypeata, together with five cercarial and four metacercarial isolates from nine snails. The genetic divergence estimated among the 13 isolates was very low, ranging from 0 to 0.6%. Phylogenetic analyses inferred by maximum likelihood and Bayesian methods showed that all isolates of E. recurvatum form a single clade with strong support. The presence of E. recurvatum in P. cubensis and A. clypeata from central Mexico represents new host reports, and extends the distribution range in the Americas.

This study aimed to compare three qualitative parasitological methods for the diagnosis of Syphacia muris infection in 30 Wistar rats (Rattus norvegicus) infected naturally. Methods of spontaneous sedimentation (Hoffman, Pons and Janer, or HPJ) and spontaneous flotation (Willis) for faecal samples and a method of taping (Graham) were performed and compared. The Graham and Willis methods were more sensitive than the HPJ method (P< 0.05). The Graham method was able to detect S. muris eggs in 100% of the samples. Eggs were detected in 83% and 60% of the samples using the Willis and HPJ methods, respectively. Method choice is important for screening for parasites of rats kept under laboratory conditions, as accurate diagnosis helps prevent future environmental contamination and infection. We concluded that the Graham method was the most efficient of those tested in this study for detection of S. muris infection in rats. This method is also rapid, inexpensive and practical, and should be implemented as a necessary measure for infection control.

During a study of the larval trematodes infecting the fresh-water molluscs of Llangorse Lake, South Wales, twenty-one species of cercariae have been encountered. The present paper deals with the Furcocercariae. Six new species are described in detail and the remaining two compared with the description of previous workers.

Crude saline extracts of Trichinella spiralis and T. pseudospiralis infective larvae were studied by Western blot analysis using a monoclonal antibody, named ES/TA2 and produced against T. spiralis larvae. This monoclonal antibody recognized seven major antigenic components in T. spiralis larvae with apparent Mr: 45, 48, 50, 68, 70, 92 and 105 kDa and five in T. pseudospiralis larvae: 38, 50, 70, 72 and 92 kDa. SDS-PAGE of both extracts did not reveal appreciable differences in the range of molecular weights recognized by ES/TA2. These facts show the existence of immunological differences among proteins with apparently identical molecular weights.

Of 10,362 cattle examined in Bangladesh, 4,368 (42·15%) harboured hydatid cysts. One to three-year-old cattle had the lowest (11·34%) and those over nine years old the highest (93·21%) infections. Organ involvement was as follows: liver 35·18%, lungs 32·02%, spleen 0·80%, heart 0·41%, kidney 0·25%, omentum 0·11% and both liver and lungs 31·20%. Fertile cysts occurred in 8·11%, sterile in 74·91%, calcified in 9·43%, suppurative in 6·04% and undeveloped in 1·51% of animals.

The plant parasitic nematode, Tylenchus dipsaci Kühn, commonly known as the stem eelworm, or alternatively when occurring in narcissus, the bulb eelworm, is a major pest of a wide range of cultivated plants. Accurate knowledge concerning the detailed life-history of the nematode is still of limited extent, despite the large numbers of workers who, throughout Europe and more recently North America, have devoted much time to a study of the subject. In particular it is clear that much remains to be learned concerning the “biologic strain” theory. Investigators, probably without exception, agree that a large number of, so-called, biologic strains of the worm occur. Each of these strains, while morphologically identical with the others, appears to be restricted more or less rigidly to a particular species of host plant.

Two chitin synthesis inhibitors (CSIs) viz., triflumuron and hexaflumuron interfere with the development of Brugia malayi in Aedes aegypti (a black-eyed Liverpool strain). The development of B. malayi was slow in both the treated populations and the infection rate, infectivity rate and L3 load per mosquito decreased significantly (P< 0.001) in comparison with untreated controls. Hexaflumuron was found to be more inhibiting than triflumuron.

A survey of larval helminths in freshwater snails of Kinmen was conducted from 1986 to 1987. Parasitological examinations of a total of 726 live snails collected from 25 loci revealed that 20 of 80 Bithynia fuchsiana were infected with metacercariae of Echinostoma gotoi and 36 with metacercariae of other echinostomes. Among 57 Radix auricularia swinhoei snails, 27 were infected with echinostomes and with metacercariae of other flukes. Of 20 Cipangopaludina chinensis, 18 were found with larvae of echinostomes. Larval trematodes were also found in three of 37 Austropeplea ollula and two of 87 Gyraulus spirillus. Third-stage larvae of Parastrongylus cantonensis were found in Ampullarius canaliculatus (5/103), Sinotaia quadrata (20/141), Hippeutis umbilicalis cantori (1/70) and Gyraulus spirillus (2/87). Segmentina hemisphaerula were not infected. Cercariae of Centrocestus formosanus, Haplorchis pumilio and xiphidiocercaria were found in three, two and two specimens, respectively, of 37 Thiara tuberculata.

A study was conducted to determine the influence of environmental change on an endoparasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) over a 30-year period off the coast of Labrador in the north-western Atlantic, North Atlantic Fisheries Organization subareas 2J–3K. Cod, once an abundant fish species that had been commercially exploited for many decades, declined precipitously during the mid-1980s onwards. This decline was attributed to climatic changes that affected the entire food chain from zooplankton to fish, sea birds and marine mammals. A monitoring programme was introduced, sampling cod by otter trawling using research vessels. The fish, after capture, were frozen at − 20°C, subsequently thawed and the digestive tract removed and examined for the parasite in 2006. Data from samples taken in 1976, 1980–81, 1986, 1990, 2000 and 2003 were compared statistically with those collected in 2006. The results indicate a decline in the prevalence and mean abundance of E. gadi in 1986 with a minimum in 2000 but increasing gradually in 2003 and 2006. These changes were coincident initially with a decline of oceanic temperature and the entire food web, including capelin (Mallotus villosus), a preferred prey of cod and primary source of E. gadi. The increase in prevalence and mean abundance of the parasite in 2006 were associated with an increase of oceanic temperature and the return of small schools of capelin to offshore areas. Cod older than 4 years harboured a greater abundance of E. gadi than younger fish, while no difference was observed between the sexes. The results suggest that the abundance of E. gadi can be useful as a bioindicator of environmental changes in the north-western Atlantic.

Anisakid nematodes are parasites with an indirect life cycle, involving many hosts, including cetaceans that act as definitive hosts. Identification at species level is crucial for a better understanding of the epidemiology and ecology of these parasites, but an accurate diagnosis based only on morphology is difficult. In Brazil, genetic characterization of anisakids is still rare, with Anisakis typica and A. physeteris being the only two species identified by genetic markers until now. The definitive hosts of A. nascettii are Mesoplodon grayi, M. bowdoini, M. layardii and M. mirus. Geographical locations of A. nascettii include the coasts of New Zealand, South Africa and Europe. In this study, a nematode was collected from a Gervais' beaked whale, Mesoplodon europaeus, stranded in Ceará State, north-east Brazil. Genetic analysis based on 18S rDNA, internal transcribed spacer (ITS) region and mtDNA cox2 gene revealed 100% identity with Anisakis sp. U94365, 99% with Anisakis sp. (MP-2005 EU718477 A. nascettii) and 99% with A. nascettii DQ116431, respectively. Phylogenetic analyses of ITS and cox2 sequences using both neighbour-joining and maximum-likelihood methods provided strong support for a clade with only A. nascettii specimens. This study demonstrated for the first time the identification of A. nascettii in the Brazilian Atlantic Coast, revealing a wider geographical distribution of this parasite worldwide and extending the range of its definitive hosts to a new Mesoplodon species, M. europaeus, the Gervais' beaked whale.

Guineapigs infected by mouth with eggs of A. suum developed an acquired resistance to reinfection 27, 35 and 51 days later. Resistance of the host was manifested by: survival following a lethal dose of eggs; an inhibition of larval migration; a retardation of larval growth; and the ability to maintain or gain weight.

By means of the conglutinating complement absorption test, using a saline extract of worm as antigen, antibodies were detected in the serum of resistant guineapigs seven days after the second reinfection. Antibodies were not detected in the serum of nonresistant guineapigs seven days after one infection. There was some evidence to indicate that the conglutinating antibody titre of the serum is a measure of the host's ability to resist infection.

In a previous paper, Peters & J. Leiper (1940) pleaded that, in anthelmintic experiments, the statistical problem of variation should be considered, not only so as to assess the significance of treatment differences after the results have come to hand, but also with a view to the prior construction of an experimental design capable of giving reliable answers to the questions posed. Reference was made to the “Enormous expenditure of time, labour and money” on anthelmintic experiments, the results of which usually remain undigested and of unknown significance.

While the paper was passing through the press a symposium on phenothiazine as an anthelmintic, led and summarized by Taylor & Sanderson (1940), was published in the Veterinary Record. The symposium deals with “Work carried out in various parts of the country and co-ordinated through the Agricultural Research Council” it covers some 150 horses, 300 to 400 sheep, 70 to 80 goats, and a few cattle, pigs, and dogs. The drug was found to be remarkably efficient against horse strongyles and the stomach-worms of ruminants, and in varying degree less efficient against other worms.

Extensive tables of egg-counts, worm-counts, and weights of animals are published in the symposium. It was usual to count eggs or weigh animals once before treatment and several times afterwards. The repeated after-treatment determinations are made in order to detect a general trend in egg-counts or weights: in other words there is no attempt to measure and make allowance for the very considerable upand- down variation from day to day.

This paper reports on two species of digenetic trematodes, namely Gymnophallus deliciosus (Olsson, 1893) and Notocotylus chionis Baylis, 1928, from Sheathbills collected on Signy Island.(lat. 60° 43' S., long. 45° 36' W.), South Orkney Islands, in July and October 1965 by Mr Charles Howie of the British Antarctic Survey. The birds were preserved in deep-freeze and later passed to us for examination. An account of the cestode parasites of these birds has been given previously (Jones & Williams, 1967).

Goezia lacerticola sp. n. infects the American alligator, Alligator mississippiensis, in Florida. The stomach ascaridoid is characterized by possessing 28 – 32 pairs of caudal papillae of which 4 are postcloacal, 2 are paracloacal, and the rest are precloacal; a body length of 3.9 – 8.2 mm, spicules 8 – 16% of the body length; and a length-ratio of the intestinal caecum to ventricular appendage of 1:2.1 – 4.6 mm. Its ventricular appendage consists of two longitudinal compartments.

Explanatum explanatum flukes, liver amphistomes of ruminants, cause significant economic loss in the livestock industry by inducing severe liver damage. A total of 66 flukes from 26 buffaloes and 7 cattle in four different geographic areas of Bangladesh and 20 flukes from 10 buffaloes in the Chitwan district of Nepal were subjected for analysis. The sequences (442 bp) of the second internal transcribed spacer (ITS2) of ribosomal DNA and the variable fragments (657 bp) of mitochondrial nicotinamide dehydrogenase subunit 1 (nad1) of E. explanatum flukes from Bangladesh and Nepal were analysed. The aim of this study was molecular characterization of the flukes and to elucidate their origin and biogeography. In the ITS2 region, two genotypes were detected among the flukes from Bangladesh, while flukes from Nepal were of only one genotype. Phylogenetic analyses inferred from the nad1 gene revealed that at least four divergent populations (groups I–IV) are distributed in Bangladesh, whereas two divergent populations were found to be distributed in Nepal. Fst values (pairwise fixation index) suggest that Bangladeshi and Nepalese populations of group I to IV are significantly different from each other; but within groups III and IV, the populations from Bangladesh and Nepal were genetically close. This divergence in the nad1 gene indicates that each lineage of E. explanatum from diverse geography was co-adapted during the multiple domestication events of ruminants. This study, for the first time, provides molecular characterization of E. explanatum in Bangladesh and Nepal, and may provide useful information for elucidating its origin and dispersal route in Asia.