The material upon which this study is based was obtained from a Grey Sand-Hamster (Cricetulus griseus) which died in captivity at the experimental farm of the Institute of Agricultural Parasitology. Several examples of two species of hamster were received from Dr. Hindle on his return from China, the specimen furnishing the worms being one of these. On death a post-mortem examination of the animal was made and the cestodes removed and preserved in dilute formalin. Some weeks subsequently the parasites were examined and found to differ from the descriptions of other species of Hymenolepis encountered in hamsters and the present study was entered upon.

The filarial parasites Litomosoides carinii and Dipetalonema viteae both show transcuticular uptake of adenosine 3′, 5′-cyclic monophosphate but isoproterenol is taken up by D. viteae only. The importance of this difference is discussed from the point of view of metabolic regulation. Inhibition of uptake by lectins indicates the involvement of surface sugar moieties in the transport processes.

Mature hens were induced to moult and were subsequently found to be resistant to both primary and secondary infections of Raillietina cesticillus, whereas non-moulting birds that continued to lay were susceptible to primary and secondary infections.

In a recent survey of nematodes associated with tobacco in Shandong, China, the root-lesion nematode Pratylenchus coffeae was identified using a combination of morphology and molecular techniques. This nematode species is a serious parasite that damages a variety of plant species. The model plant benthi, Nicotiana benthamiana, is frequently used to study plant-disease interactions. However, it is not known whether this plant species is a host of P. coffeae. The objectives of this study were to evaluate the parasitism and pathogenicity of five populations of the root-lesion nematode P. coffeae on N. benthamiana. N. benthamiana seedlings with the same growth status were chosen and inoculated with 1,000 nematodes per pot. At 60 days after inoculation, the reproductive factors (Rf = final population densities (Pf)/initial population densities (Pi)) for P. coffeae in the rhizosphere of N. benthamiana were all more than 1, suggesting that N. benthamiana was a good host plant for P. coffeae. Nicotiana. benthamiana infected by P. coffeae showed weak growth, decreased tillering, high root reduction, and noticeable brown spots on the roots. Thus, we determined that the model plant N. benthamiana can be used to study plant-P. coffeae interactions.

1. The infective stage larvae of Bunostomum trigonocephalum (Rudolphi, 1808) penetrate the intact skin and undergo skin-lung migration in the mouse and skin-lung-intestine migration in the guineapig. After percutaneous infection in guineapigs, they moult in the lungs to the fourth stage and to the fifth stage in the intestine. Relatively few of them undergo this partial development in the guineapig and they are stunted in growth.

2. In the abnormal hosts, the penetrating larvae cause extensive tissue disorganisation. The histopathology of the skin and lungs is described. There is a cellular reaction to the parasites.

3. In guineapigs, the infective stage larvae reach the lungs after per os infection but they are few in number do no persist for more than six days.

Acanthocephalans are common intestinal parasites of marine mammals, the most widespread of which is the genus Corynosoma. In this study, parasite infrapopulations of two closely related species of Corynosoma were examined: Corynosoma enhydri from sea otters (Enhydra lutris) in Alaska (n = 12) and California (n = 19), and Corynosoma strumosum from seals in Germany (n = 22). Prevalence of C. enhydri was 100% in Californian otters, with a mean abundance of 30, and 83% in Alaskan otters, with a mean abundance of 232. In seals, C. strumosum had a prevalence of 65%, with a mean abundance of 33. Female C. enhydri dominated both Californian (82%) and Alaskan (79%) infections, while, in seals, female C. strumosum made up 68% of the parasite population. Reproduction rates for C. enhydri, with 16% (California) and 18% (Alaska) of females mated, were low compared to C. strumosum in seals, of which 40% of females were mated. Habitat selection also differed significantly between the two species. Corynosoma enhydri was found most frequently in the second and third fifths of the small intestine, while C. strumosum was found most frequently in the fourth. The differences in habitat selection and prevalence analysed in this study may be related to a trade-off between growth and reproduction between the two species.

Experimental infections of pre-adult Galba truncatula (two populations) using one, two, three or five miracidia of Fasciola hepatica per snail were carried out to determine the total number of cercariae produced by snails when they were sacrificed at day 70 post-exposure (at 24°C). When the number of miracidia used for each snail increased at exposure, significant numerical augmentations of live rediae and of intraredial differentiating cercariae were noted. In contrast, only insignificant differences between mean numbers of free cercariae were found. The number of metacercariae produced by each snail (after shedding and/or after dissection) increased in infections with up to three miracidia per snail in each population and strongly decreased in infections with five miracidia per snail. Compared to the other types of infections, the delay of cercarial differentiation noted in the five-miracidia groups was probably due to the volume of the snail host, which would be too small to assure the complete development of five sporocysts.

Intestinal helminth infections constitute a major health problem in low socio-economic communities worldwide. A cross-sectional study was conducted in children aged between 12 and 60 months. A structured questionnaire was used to collect socio-demographic data and stool samples were subjected to direct smear, stained with Lugol's iodine, and formaldehyde–ether concentration techniques to determine the prevalence of intestinal helminth infections. The circumference of each child's left mid upper arm (MUAC) was measured using standard procedures. Two hundred and six children with a mean MUAC of 14.7 cm (SD ± 1.1) were assessed from September to December 2014. The prevalence of acute energy undernutrition was 6.3% (13/206). All of them had moderate acute undernutrition and no cases of severe acute undernutrition. Paternal occupation was significantly associated with MUAC. Intestinal helminth infections were detected in 12.6% of children. Four species of parasites were identified; Ascaris lumbricoides (9.7%) followed by Enterobius vermicularis (1.5%), Trichuris trichiura (1.0%) and hookworms (1.0%). Uninfected children aged between 1 and 2 years showed significantly higher MUAC than infected children. No statistically significant association was detected between the severity of intestinal helminth infections and MUAC. Although intestinal helminth infections are a major public health problem in this community, they are not related to MUAC. Future research, providing more insight into the nutritional impact of intestinal helminth infections, is required to determine the association between parasitic infections and physical growth in this community.

Five Swainson's spurfowl collected in Free State Province, South Africa, were examined for helminth parasites, and the nematodes Acuaria gruveli, Cyrnea parroti, Gongylonema congolense, Subulura dentigera, Subulura suctoria and a new Tetrameres species were recovered. Their respective prevalence was 100, 20, 80, 20, 20 and 20%. These nematodes are all new parasite records for Swainson's spurfowl, and Acuaria gruveli constitutes a new geographical record as well. A single specimen of Cyrnea eurycerca was found in an Orange River francolin, representing a new host and geographical record for this parasite. The new species, for which the name Tetrameres swainsonii is proposed, can be differentiated from its congeners by a combination of the following characters of males: two rows of body spines, a single spicule which is 1152–1392 μm long, and eight pairs of caudal spines arranged in two ventral and two lateral rows of four spines each. The single female has the globular shape typical of the genus.

An in vivo study in goats evaluated the effect of superimposing a single artificial infection with a benzimidazole (BZ)-susceptible Haemonchus contortus isolate upon established H. contortus populations of known BZ resistance by measuring the phenotypic BZ resistance of eggs collected from faeces before and after re-infection. Two H. contortus isolates, one benzimidazole resistant (BZR) and the other susceptible (BZS), were used to infect worm-free goats. Eight goats were initially infected with 2000 third-stage larvae (L3). In each case the inoculum contained a pre-determined proportion of the two isolates: 100% BZS (one goat), 75% BZS/25% BZR (two goats), 50% BZS/50% BZR (two goats), 25%BZS/75% BZR (two goats) and, finally, 100% BZR (one goat). The phenotypic BZ susceptibility of the H. contortus population formed in each goat after the first infection was determined on days 30 and 36 post-infection using an egg-hatch assay (EHA) that estimated the concentration of thiabendazole (TBZ) required for 95% inhibition of larval hatching (EC95) with a 95% confidence interval (95% CI). On day 49 post-infection, goats were re-infected with 2000 L3 of the BZS isolate alone. A second set of EHA bioassays was performed 28 days and 34 days after re-infection. The first infection protocol produced three populations classified as BZS (EC95 0.055–0.065 μg TBZ/ml) while four were categorized as BZR (EC95 0.122–0.344 μg TBZ/ml). The status of one other population could not be determined. After re-infection with BZS L3, the number of susceptible populations increased to six (EC95 0.043–0.074 μg TBZ/ml) while the remaining two were deemed resistant (EC95 0.114–119 μg TBZ/ml). Re-infection with BZS L3 thereby reduced the resistance status of most H. contortus populations.

Adult specimens of Andracantha gravida (Alegret, 1941) were recorded from the intestines of the double-crested cormorant Nannopterum auritus (Lesson) (type host) and brown pelican Pelecanus occidentalis L. in two localities from Mexico: Celestún, Yucatan (south-eastern) and Punta Piedra, Tamaulipas (north-eastern). The specimens of A. gravida are morphologically characterized by having a pipe-shaped body without swellings, the absence of small trunk spines between the two fields of spines on the foretrunk and a cylindrical proboscis with 14–16 rows of 10–12 hooks per row. Newly generated partial sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were generated from adult isolates of A. gravida from Mexico and compared with one sequence of A. gravida and with sequences of other polymorphid acanthocephalans available in GenBank. Phylogenetic analyses based on maximum likelihood and Bayesian inference methods of the cox1 dataset placed all the species of Andracantha in a single clade, with weak support. The analyses of the cox1 dataset placed Andracantha sigma Presswell, García-Varela & Smales, 2018, as sister to the clade formed by A. gravida, Andracantha phalacrocoracis (Yamaguti, 1939), Andracantha leucocarboi Presswell, García-Varela & Smales, 2018 and an unidentified species of Andracantha from Japan. The newly generated cox1 sequences of A. gravida from piscivorous birds of Mexico formed a strongly supported clade with the published sequence of A. gravida from the double-crested cormorant from the south-eastern coast of Mexico. The intraspecific genetic divergence among isolates identified as A. gravida ranged from 0.0% to 2.2%. A cox1 haplotype network inferred with 14 sequences revealed the presence of nine haplotypes, two of which were shared between the populations of piscivorous birds from the north-eastern and south-eastern coasts of Mexico and seven of which were unique. The fixation index between the populations from north-eastern and south-eastern Mexico was low (0.06949), which suggests genetic flow. This can be explained by the migration patterns of the brown pelican and the double-crested cormorant along the coasts of the Gulf of Mexico.

A co-relation between Schistosoma japonicum (Sj) and liver cancer (LC) in humans has been reported in the literature; however, this association is circumstantial. Due to the inconclusive nature of this association, the International Agency for Research on Cancer has placed Sj in Group 2B for LC, signifying it to be a ‘possible carcinogen’. Many epidemiological, pathological and clinical studies have identified multiple factors, linked with Sj infection, which can lead to liver carcinogenesis. These factors include chronic inflammation in response to deposited eggs (which leads to fibrosis, cirrhosis and chromosomal instability at cellular level), hepatotoxic effects of egg-antigens, co-infection with hepatitis viruses, and up-regulation of glycolysis linked genes among others which predisposes hepatic tissue towards malignant transformation. The objective of this work is to present the current understanding on the association of Sj infection with LC. Mechanisms and factors linked with Sj infection that can lead to LC are emphasized, along with measures to diagnose and treat it. A comparison of liver carcinogenesis is also provided for cases linked with and independent of Sj infection. It appears that Sj, alone or with another carcinogen, is an important factor in liver carcinogenesis, but further studies are warranted to conclusively label ‘infection with Sj alone’ as a liver carcinogen.

The plant-parasitic cyst nematode Heterodera glycines requires a host plant to complete its life cycle, which involves hatching of infective juveniles that parasitize through root entry. A laboratory population of H. glycines grown on soybean, Glycine max, undergoes a sharp increase in maturity between 5 and 6 weeks in culture, as measured by the proportion of eggs containing well developed pre-hatch juveniles (late development eggs) versus eggs without visible juveniles (early development eggs). The median percent of eggs classified as late development, representing all samples taken from 4 to 7 weeks in culture, was 61%. For all samples taken up to 5 weeks, 80% scored below the median. In samples taken after 5 weeks, 15% scored below the median. This shift in population maturity was accompanied by a significant increase (P < 0.01) in the number of hatched juveniles present in each sample. There was also a significant increase (P < 0.02) in amount of FaRP-like peptide detected by specific ELISA. Total FaRP levels increased from 0.18 ± 0.07 fMol FLRFamide equivalents per ng protein in early development eggs to 0.40 ± 0.17 in late development eggs. The level remained high in hatched juveniles. HPLC/ELISA detected as many as nine potential FaRPs in H. glycines, two of which were specifically increased (P < 0.005) in hatched juveniles. The association of FaRPs with maturing eggs and the possible involvement of these neuropeptides with juvenile hatching and motility are discussed.

Natural selection should favour parasite genotypes that manipulate hosts in ways that enhance parasite fitness. However, it is also possible that the effects of infection are not adaptive. Here we experimentally examined the phenotypic effects of infection in a snail–trematode system. These trematodes (Atriophallophorus winterbourni) produce larval cysts within the snail's shell (Potamopyrgus antipodarum); hence the internal shell volume determines the total number of parasite cysts produced. Infected snails in the field tend to be larger than uninfected snails, suggesting the hypothesis that parasites manipulate host growth so as to increase the space available for trematode reproduction. To test the hypothesis, we exposed juvenile snails to trematode eggs. Snails were then left to grow for about one year in 800-l outdoor mesocosms. We found that uninfected males were smaller than uninfected females (sexual dimorphism). We also found that infection did not affect the shell dimensions of males. However, infected females were smaller than uninfected females. Hence, infection stunts the growth of females, and (contrary to the hypothesis) it results in a smaller internal volume for larval cysts. Finally, infected females resembled males in size and shape, suggesting the possibility that parasitic castration prevents the normal development of females. These results thus indicate that the parasite is not manipulating the growth of infected hosts so as to increase the number of larval cysts, although alternative adaptive explanations are possible.

In order to determine whether Taenia solium can be maintained in the laboratory using rodents as definitive hosts, six nude rats, 20 immunosuppressed Mongolian gerbils and 20 immunosuppressed Syrian hamsters were each inoculated through a stomach tube with three cysticerci recovered from SCID mice. No adult worms of T. solium were found in the intestinal tract of any of these 46 rodents. In addition, five immunosuppressed Syrian hamsters were fed with the same number of cysticerci enclosed in rodent muscles from SCID mice. Two of these hamsters were found to be infected 40 days post-infection, each harbouring a sexually developed worm in the intestinal tract. Although no eggs were produced, prepatent infections may be possible if a longer time was allowed for worm development. Moreover, the maintenance of the life cycle of T. solium in the laboratory using the rodent model can be established.

Little is known about helminth parasites of the Bismarck Archipelago, in either archaeological or modern contexts. This study presents a parasitological analysis of soil samples from Early Lapita habitation layers at Kamgot (3300–3000 BP). Evidence for the presence of pigs and dogs and the timing of their arrival in Early Lapita contexts have been contested in the literature. The finding of parasite eggs in samples from Kamgot supports the presence of pigs and dogs at the site. Six types of helminth eggs were identified: pig nematode Trichuris suis, dog nematode Toxocara canis, and cestode Dipylidium caninum, as well as two unknown trematodes and a possible anoplocephalid cestode, thereby indicating the local presence of other mammals or birds. This study represents the first confirmed record of ancient helminth parasites in tropical Oceania.