Hook dimensions of Multiceps glomeratus show that the hooks are capable of reaching full adult size in the coenurus stage.

The available material showed that M. serialis hooks were slightly larger than those of M. glomeratus in the adult stage; in the coenurus stage the differences were not significant.

Statistically, the dimensions measuring the length of the blade of the hook are the most satisfactory.

There are significantly large variances in most cystic hook dimensions from one cyst to another, and from one scolex to another within a single cyst, but not from one group of scolices to another. It follows that in biometric work it is important to sample several scolices from each cyst, and several cysts of any one species, but that groups can be disregarded.

The variability of most hook measurements is in the region of 5%; i.e. the standard deviation is about 5% of the mean dimension.

The danger of extensive generalisation from limited data should be guarded against. Thus, while the species variance was significantly larger than the cyst variance in the case of adult hooks in the material available, it is quite possible that this would no longer have been the case if material from other sources had been available.

Migration and distribution of Ancylostoma caninum larvae in the tissues of Swiss albino mice infected with 500,1000, 2000 and 4000 larvae was studied. Larval migration and distribution in the different tissues was earlier in mice infected with a dose of 4000 larvae and more larvae were expelled from the gastrointestinal tract of heavily infected (2000 dose) mice. With an infective dose of 1000 larvae, the percent larval yield was higher than in other two groups (500 dose and 2000 dose) showing poor expulsion. Larval migration in the lungs was high even on the 1st day in heavily infected groups. Migration of larvae into the muscles, particularly of the head, neck and thorax took place on the very first day and was proportional to dose level. Larval count was higher in the muscles of the head and neck until the 9th day, after which it was high in the thoracic and other regions.

Groups of ferrets inoculated with Dracunculus insignis were treated with various anthelminthic compounds to evaluate the potential use of drugs in controlling the human parasite D. medinensis. The three primary compounds tested were diethylcarbamazine (DEC), albendazole (ALBZ), and ivermectin (IVER); they were administered in dosages of 60 mg/kg, 10 mg/kg, and 1 mg/kg, respectively. Groups of animals received treatment either once at 60 days after inoculation, once at 60 and 90 days, or for 3 days at either 60 or 90 days postinoculation. The most marked decrease occurred in the animals that received treatment once at 60 and at 90 days after inoculation. This was observed for all three drugs tested. Increased dosages, i.e., 3 days of treatment at 60 or 90 days did not result in decreased worm burdens. In no group was there a statistically significant reduction in worm burden when compared with controls. Two other compounds, metrifonate and CGP 6140, were tested in a more limited manner, but again the worm recovery rates were comparable with those in control groups. It would appear that existing drugs commonly used to treat helminthic infections are poor candidates for use in the campaign to eradicate guinea worm disease.

A re-examination of the life-cycle of the mouse pinworm, Aspiculuris tetraptera has shown that the infective eggs hatch in the lower intestine or in the caecum of the host, to release the first stage larvae. After moulting, these larvae migrate into the crypts of the colon; those larvae which do not migrate into the crypts apparently pass out of the host with the faeces. The larvae in the crypts, presumably the third stage, later return to the lumen of the colon where they mature into adults. Males are mature by about the 20th day and females by the 23rd day. Viable eggs are released by the females 24 days after infection.

Given their sheer cumulative biomass and ubiquitous presence, parasites are increasingly recognized as essential components of most food webs. Beyond their influence as consumers of host tissue, many parasites also have free-living infectious stages that may be ingested by non-host organisms, with implications for energy and nutrient transfer, as well as for pathogen transmission and infectious disease dynamics. This has been particularly well-documented for the cercaria free-living stage of digenean trematode parasites within the Phylum Platyhelminthes. Here, we aim to synthesize the current state of knowledge regarding cercariae consumption by examining: (a) approaches for studying cercariae consumption; (b) the range of consumers and trematode prey documented thus far; (c) factors influencing the likelihood of cercariae consumption; (d) consequences of cercariae consumption for individual predators (e.g. their viability as a food source); and (e) implications of cercariae consumption for entire communities and ecosystems (e.g. transmission, nutrient cycling and influences on other prey). We detected 121 unique consumer-by-cercaria combinations that spanned 60 species of consumer and 35 trematode species. Meaningful reductions in transmission were seen for 31 of 36 combinations that considered this; however, separate studies with the same cercaria and consumer sometimes showed different results. Along with addressing knowledge gaps and suggesting future research directions, we highlight how the conceptual and empirical approaches discussed here for consumption of cercariae are relevant for the infectious stages of other parasites and pathogens, illustrating the use of cercariae as a model system to help advance our knowledge regarding the general importance of parasite consumption.

This study tested the hypotheses that ants (Formicidae) function as a first intermediate host of Mesocestoides (Cestoda: Mesocestoididae) and that deer mice (Peromyscus maniculatus) develop metacestode infections after ingesting cysticercoid or procercoid-infected ants. Field studies were conducted at an island fox (Urocyon littoralis littoralis) breeding facility located on San Miguel Island, California Channel Islands National Park, USA, where >40% of captive foxes were infected with adult Mesocestoides. Eight percent (8%) of deer mice at the fox pen site were infected with Mesocestoides metacestodes while none were infected at a distant site where foxes were absent (campground), thereby indicating the potential localized presence of a first intermediate host. To test whether ants from San Miguel Island contained Mesocestoides DNA, a polymerase chain reaction (PCR)-based diagnostic assay was developed using nested primers that could detect a single hexacanth larva within pooled samples of ten ants. Ants (Lasius niger and Tapinoma sessile) collected near the fox breeding facility were tested using the nested-PCR assay. Seven of 223 pooled samples of L. niger (3.1%) and 2 of 84 pooled samples of T. sessile (2.4%) tested positive for Mesocestoides DNA, while none of the ants were positive at the campground site. Positive samples were sequenced and found to match DNA sequences from Mesocestoides obtained from island fox and deer mice. Finally, to determine whether ants function as a first intermediate host for Mesocestoides, colony-raised deer mice (n=47) were fed L. niger (n=3860) or T. sessile (n=339) collected from the San Miguel Island fox breeding facility. No mouse became infected with Mesocestoides metacestodes after ingesting ants. While both L. niger and T. sessile from SMI were positive for Mesocestoides DNA, they were not infective to deer mice in the laboratory.

A total of 358 cattle was examined for schistosome infection in Zambian slaughterhouses. A total of 542 worms collected from 104 infected individuals was examined for glucose-6-phosphate dehydrogenase and phosphoglucomutase using isoelectric focusing. The overall prevalence of infection was 51%. Ninety three percent of the infected animals had less than 100 worm pairs in the mesenteric veins. Schistosoma mattheei was the predominant species (75%); S. leiperi (12%) and S. margrebowiei (2%) were also identified. The remaining 11% of the worms showed one of two distinct heterozygote patterns. Pattern A is identical to that of a laboratory-produced Fl S. mattheei × S. haematobium hybrid, but could also represent a S. mattheei × S. leiperi hybrid. Further studies are required to elucidate the origins of pattern B.

Conjunctivitis due to the trematode Philophthalmus in a 13-year-old Israeli girl is described. A single worm, probably a mature Philophthalmus palpebrarum, was detected on the palpebral conjunctiva of the upper eyelid of the right eye. Removal of the worm resulted in rapid abatement of the ocular symptoms. This is the first documentation of human philophthalmosis in Israel.

Restriction endonuclease analysis of mitochondrial DNA was carried out in order to differentiate diploid and triploid types of Paragonimus westermani originating from Japan. It was found that out of 16 restriction enzymes. PstI, HaeIII and RsaI revealed consistently different cleavage patterns between the two types.

The freshwater snail, Bithynia tentaculata (Gastropoda: Prosobranchia), is frequently found in gravel pits and its role in the transmission of larval digeneans was assessed in one of these unstable water bodies from the Lower Thames Valley (UK) from June 1982 to December 1984. Eight species of cercarial and five species of metacercarial infections were reported from B. tentaculata, with up to 7.7% and 4.7% prevalence of infections, respectively, occurring in the snail, making it the most important host at this site. Seasonal peaks in cercarial infections occurred in late autumn/early winter but little seasonality was apparent in the occurrence of metacercarial infections. The life history characteristics of both hosts and parasites, which can affect intramolluscan digenean dynamics, are discussed.

In a paper published towards the end of last year the author (Goodey, 1927) described a new free-living species of Aphelenchus, A. winchesi, and dealt with the type species of the genus A. avenæ, discussing its affinities to certain nearly related species. A further paper was promised dealing with the various species of the genus and the present communication is an attempt to fulfil that promise.

The population dynamics of Labratrema minimus (Stossich, 1887) metacercariae (Trematoda, Bucephalidae) were studied in its second intermediate fish host Atherina boyeri from Salses-Leucate lagoon (Northwest Mediterranean Sea, South of France), during the cercarial shedding period. The infection parameters (prevalence and mean abundance of infection) showed the high susceptibility of silversides (juveniles and adults) to infection. The observed variation in the mean abundance of infection with respect to time and host size was explained by (i) the susceptibility of A. boyeri to multiple successive infections (increase in abundance of infection with host length and raising of parasite burden until August) and (ii) the loss, probably by more rapid death, of heavily infected silversides from each host size group (decrease in abundance of infection in September within each host size group, stability of the parasite burden within the older class of hosts over the whole period, premature decrease in the condition factor in August). Finally, it was deduced that the infection pattern observed over the May–September period was a dynamic process controlled by: availability of infective cercariae, influx of newborn silversides free of metacercariae until September, high susceptibility of juvenile and adult A. boyeri to infection, metacercarial loss and probably by parasite-induced host mortality.

This study was conducted in order to investigate the epidemiology of filarial species in a region of central Italy (Tuscany) in dogs that did not undergo prophylaxis for filariasis. From 2007 to 2009, 630 blood samples were collected from 40 kennels throughout the regional territory. Samples were analysed with Knott's modified test and with an enzyme-linked immunosorbent assay (ELISA) for the detection of Dirofilaria immitis antigens, those positive for microfilariae were also subjected to histochemical staining for acid phosphatase activity to validate the identification of the species. An overall elevated prevalence of filariasis (23.2%) was found. Dirofilaria immitis and D. repens were found to be the dominant species, with similar prevalences (12.5% and 12.1% respectively), while Acanthocheilonema reconditum was less common (1.9%). Results of this study indicate that monitoring for filariasis should be kept at a high level. A constant monitoring of the canine sanitary status should also be carried out for the protection of human health, considering the zoonotic potential of filarial worms.

A new nematode species, Philometra floridensis sp. n. (Philometridae), is described from male and female specimens found in the ovary of red drum, Sciaenops ocellatus (Linnaeus) (Sciaenidae, Perciformes), from the Gulf of Mexico off Treasure Island, Florida, USA. Based on light and scanning electron microscopy examination, the new species differs from most other gonad-infecting Philometra spp. in having a smooth gubernaculum with a distinct dorsal tooth on the distal tip. The new species is most similar to P. carolinensis Moravec, de Buron & Roumillat, 2006, but differs in length and shape of spicules. It can be distinguished from P. carolinensis and other species with unknown males, by the markedly greater body length of gravid females (up to about 100 cm). Philometra floridensis is the third valid gonad-infecting species of Philometra reported from sciaenids.

Parasitic nematodes of the family Mermithidae were found to be infecting the introduced European earwig Forficula auricularia (Dermaptera: Forficulidae) in Dunedin, South Island, New Zealand. Adult females were later collected from various garden plants while depositing eggs. These mermithid specimens were identified morphologically as Mermis nigrescens Dujardin, 1842. A genetic distance of 0.7% between these specimens and a M. nigrescens isolate from Canada (18S rRNA gene), suggests that they have diverged genetically, but there are currently no available comparable sequences for the European M. nigrescens. Two additional nuclear fragments were also amplified, the 28S rRNA and the ribosomal DNA first internal transcribed spacer (ITS1), providing a basis for future studies. Bearing in mind the morphological similarity with other reported M. nigrescens and the lack of sequence data from other parts of the world, we retain the name M.nigrescens, and suggest that the species may be found to represent a complex of cryptic species when more worldwide data are available. Herein, we present a brief description of the post-parasitic worms and adult females, along with an inferred phylogeny using 18S rRNA gene sequences.

The material of Eurytrema pancreaticum from Hyderabad (Deccan) was examined and found to agree with the material of this species from China and Japan, described by Looss (1907) except in the case of cirrus sac which terminates anterior to ventral sucker.

Numerous specimens of the variety of E. pancreaticum with deeply lobed testes from the pancreatic ducts of a cow in Bengal were examined and it is found that the smaller and the larger forms belong to the same species. Variations occurring in several organs of this variety have been recorded.

A discussion on the existing species of Eurytrema has been evoked and these have been grouped under five subgenera, four of which being new ones.

The species E. ovis, E. robustum and E. cuyabai are considered to be synonyms of E. pancreaticum, E. lubens and E. intermedium respectively.

The species E. parvum Travassos, 1916 being a homonym the name E. travassosi has been suggested for it.

Paradistomum moghei n.sp. has been described and separated from the existing species of Paradistomum.

Mesoccelium leiperi n.sp. has been described and separated from the existing species of Mesocalium.

Mesoccelium sociale has been recorded from Rana tigrina and measurements of some of its organs are given.

The prevalence of the digenean Plagiorchis sp. was investigated in a natural wood mouse population (Apodemus sylvaticus) in a periaquatic environment. Classical identification was complemented with the use of molecular differentiation to determine prevalence and verify species identity. Use of the complete ITS1-5.8S rDNA-ITS2 and partial 28S rDNA gene sequences have confirmed that the species reported at this location was Plagiorchis elegans and not Plagiorchis muris as reported previously. This underlines the difficulties in identification of these morphologically similar parasites. Plagiorchis elegans is typically a gastrointestinal parasite of avian species but has also been reported from small mammal populations. Although the occurrence of this digenean in A. sylvaticus in the UK is rare, in the area immediately surrounding Malham Tarn, Yorkshire, it had a high prevalence (23%) and a mean worm burden of 26.6 ± 61.5. The distribution of P. elegans followed a typically overdispersed pattern and both mouse age-group and sex were determined to be two main factors associated with prevalence. Male mice harboured the majority of worms, carrying 688 of 717 recovered during the study, and had a higher prevalence of 32.4% in comparison to only 8.7% in the small intestine of female mice. A higher prevalence of 43% was also observed in adult mice compared to 14% for young adults. No infection was observed in juvenile mice. These significant differences are likely to be due to differences in the foraging behaviour between the sexes and age cohorts of wood mice.

Infective larvae of Wuchereria, Brugia, Breinlia, Dirofilaria and Setaria species from an experimental vector, Aedes togoi, are compared. The distinctive bubble-like caudal papillae of Wuchereria bancrofti are readily distinguishable from the protuberant ones of Brugia spp; the ‘ear-like’ papillae of Breinlia are distinct from the ‘knob-like’ ones of Dirofilaria or the ‘thorn-like’ terminal papilla of Setaria.

The evolution of the life cycles of the members of the family Dipetalonematiidae Wehr, 1935 (Filarioidea) is considered in the light of existing knowledge of spirurid nematodes. The hypothesis that the life cycles of the dipetalonematids originated from life cycles similar to those of Draschia megastoma, Habronema muscae and H. microstoma is considered to be incorrect. Alternatively, it is pointed out that in the primitive subfamily Thelaziinae Baylis and Daubney, 1926 there are forms with typical spiruroid life cycles (Rhabdochona ovifilamenta), forms with life cycles approaching those of the dipetalonematids (Thelazia spp.), and forms with life cycles intermediate between these two (Oxyspirura spp.). It is suggested that intestinal species similar to Rhabdochona gave rise to the more specialized spiruroids and forms that left the gut (Oxyspirura, Thelazia) gave rise to the dipetalonematids.

The dipetalonematids are believed to have originated from nematodes resembling the species of Thelazia and having life cycles like those of T. rhodesii, T. skrjabini and T. gulosa. Some of these worms established themselves in subcutaneous tissues. Like Parafilaria multipapillosa, they released their eggs through a break in the skin of the definitive host, thus causing a skin lesion that attracted various haematophagous arthropods which finally became involved as intermediate hosts in the life cycle. Certain species like the members of Parafilaria and Stephanofilaria (?) came to rely upon intermediate hosts that were unable to break the skin of the definitive host (Musca) and cutaneous lesions became permanent features of their life cycles. Other species became dependent upon intermediate hosts that could puncture the skin (mosquitoes, simuliids etc.) and skin lesions became unnecessary to the life cycle. The larvae of these worms then began to spread into the tissues of the skin, as found in Stephanofilaria, Onchocerca, and some species of Dipetalonema, and the infective larvae developed the ability to penetrate into the wound made by the intermediate host and perhaps, in some cases, the intact skin. Ultimately the larvae of some species habitually entered, or were deposited into, the blood stream and the adult worms were then free to colonize the vertebrate body as their larvae would then be available to the intermediate host no matter where the latter fed on the body of the definitive host; this group of worms gave rise to the many members of the family Dipetalonematidae.

The family Filariidae Claus, 1883 is briefly reviewed in the light of the above hypothesis. It is pointed out that many species, e.g. Diplotriaeninae Skrjabin, 1916, live in the air sacs of reptiles and birds and probably have life cycles similar to that of Diplotriaenoides translucidus, i.e. the eggs pass through the lungs, up the trachea and out in the faeces. It is thought that these forms may represent a separate line of evolution from that which gave rise to the Dipetalonematidae. Certain genera (Lissonema, Aprocta), occurring in the orbits of birds, probably have life cycles like Thelazia or Oxyspirura. Many other genera occurring in superficial muscles and subcutaneous tissues (Squamofilaria, Ularofilaria, Tetracheilonema, Pelecitus, Monopetalonema) may release their eggs through some sort of skin lesion. Studies on these forms are urgently needed as the details of their life cycles may shed fresh light on the origins of the more specialized filarioids.

This study investigates the use of texture, i.e. the grey level variation in digital images, as a basis for identification of strongylid eggs. Texture features were defined by algorithms applied to digital images of eggs from the bovine parasitic nematodes, Ostertagia ostertagi, Cooperia oncophora, and Oesophagostotnum radiatum. The resulting data served to establish classification criteria by linear discrimination analysis, and the criteria were subsequently evaluated by crossvalidations. From 25 texture features, ten features were selected by their significant discriminatory powers. Using a classification criterion based on these ten texture features, an average of 91.2% of eggs from the three species were correctly classified. All O. radiatum eggs were correctly classified, 11.8% of O. ostertagi and C. oncophora were reciprocally misclassified, and 2.9% of O. ostertagi were identified as O. radiatum. When the ten texture features were used singly an average of 51.2 to 37.9% of the species could be classified correctly. When texture was used together with the shape and size features, a higher percentage of eggs were correctly classified compared with the classification based on either texture, or shape and size. Hence, all O. radiatum were correctly classified as well as 88.3% of O. ostertagi and 91.2% of C. oncophora, resulting in an average of 93.1% correctly classified eggs. The rapid and accurate measurements of texture features may serve as a basis for identification or enhance performance of classification criteria based on egg shape/size.