The finding of tares or common vetch, Vida sativa L., attacked by the stem eelworm, Ditylenchus dipsaci (Kiihn) Filipjev, reported in the foregoing paper by Staniland and Southcy and the correspondence on the subject which passed between Staniland and Goodey, brought to light an interesting point in regard to the accuracy of the first record of the parasite on this particular host which calls for some comment and elucidation.

5 males and 5 females of this species were collected from the intestine of the giant African rat Cricelomys gambianus from Minaki Secondary School, near Pugu, Tanzania. Some of the specimens have parts of the host's intestinal wall tissues in their buccal capsules and some specimens have the anterior part of the intestine dark in colour. This may suggest that these nematodes attach themselves to their host's intestinal wall and probably feed on its blood.

The elongated body is cylindrical, tapering at both ends, the anterior end recurved dorsally. The cuticle is transversely striated and the buccal aperture is round, lacking a radial crown but the cuticle of the external surface of the buccal capsule forms several annular thickenings around the buccal aperture. There are 4 main external cuticular bands extending to near the buccal aperture. The buccal capsule is funnel-shaped with extremely thick and highly chitinized walls, the dorsal wall notably shorter than the ventral. The thickness of the walls is uneven, with maximum thickness posteriorly. The capsule lacks teeth and the dorsal oesophageal gland terminates near the anterior edge of the buccal capsule. The oesophageal funnel is chitinized. The oesophagus is claviform owith a wider posterior part and ends in a triradiate valve.

The alterations of mast cell counts induced in the gut of swiss albino mice by infection with Ancylostoma caninum larvae have been studied, both in single and multiple infections. It was found that mast cell rise was greater in females than males. In singly infected animals, mast cell increase was influenced by the infective dose of inoculated larvae. In case of repeatedly infected mice, mast cell counts were decreased because of their earlier degranulation.

The influence of nonspecific immunomodulation on the course of experimental infection was examined in larval cestodosis (Mesocestoides corti) and ascaridosis (Ascaris suum) in mice. Immunosuppressive treatment (with azathioprine or hydrocortisone) resulted in a decrease of resistance in both models. The subsequent administration of T-activin to immunosuppressed mice led to the restoration of resistance to a level equal to that of untreated control mice. The administration of different immunomodulators partially protected mice against M. corti (T-activin. thymomodulin) or A. suum (T-activin. thymomodulin. thymosin fr.5. bursa-activin) infection. The protective effect of different treatments did not correlate with the level of specific antibody in the sera of infected mice. These results, which confirmed the decisive role of T-cell immunity in the resistance to the helminth infections, raise the possibility of the use of immunomodulators (thymic preparations) in the immunoprophylaxis of helminthoses.

Daubaylia elegans n.sp., is described from Planorbis carinatus in the Netherlands. Tables are given of the comparative measurements of the other members of the genus. The main differences between D. elegans n.sp., and these other species are the ratio length to breadth, the length of the tail, the presence of a cuticular knob on the tail of the female and the relative size of the male genital armature.

The prevalence of guinea worm Dracunculus medinensis was determined in communities in Anambra State, Eastern Nigeria during the 1984–1985 guinea worm season. Thereafter combined intervention measures which included health education and community participation in pond treatment were introduced in one of the two communities. There was a decrease in disease prevalence from 88.7% to 33% in Group A (372 households) and from 88% to 53% in Group B (368 households), two years after control measures were introduced in Igbeagu community. However, in 345 households in Mpu community without control measures, any decrease was not significant (from 88·7% to 86·5%). Health Education combined with pond disinfection proved to be a much better intervention measure, contributing to the change in attitude and therefore decrease in disease prevalence, than pond disinfection alone.

1. The gastro-intestinal tracts of 200 mink from 42 farms were examined for helminth parasites.

2. No parasites were found in the stomach but two species of fish-borne parasite were found in the intestine.

3. Evidence of infestation with the heterophyid trematode Cryptocotyle lingua was found in twelve mink, the largest number of flukes recovered from any one mink being seven.

4. Single immature specimens of the acanthocephalid Corynosonta hadweni were recovered from four mink, but it is considered that these were not instances of true parasitism.

5. It is concluded that helminth parasites do not constitute an important hazard on mink farms in Britain;

A redescription of the aspidogastrean trematode Lobatostoma kemostoma (MacCallum & MacCallum, 1913) is provided based on examination of type material, voucher specimens available at institutional collections and newly collected specimens from the type host, Trachinotus carolinus (Linnaeus, 1766), off the Angra dos Reis, Brazil. Partial sequence of its 28S rDNA is given. Lobatostoma kemostoma can be distinguished from the other eight species of the genus by: (1) the hindbody being longer than the ventral disc; and (2) the cephalic lobes having the same shape and size. Features observed for the first time include the number and detailed arrangement of alveoli on the ventral disc, the terminal genitalia and the ovarian complex. New illustrations and morphometric data are given. In the present survey the host specificity in the genus, the validity of some morphological features and the occurrence of an Indian species of Lobatostoma from off the Brazilian coast are discussed. A lectotype of L. kemostoma from the type series deposited at United States National Parasite Collection is also designated.

Small galls on the leaves of Yarrow or Milfoil, Achillea Millefolium L., were first mentioned by Thomas (1873) but were investigated and described by Löw (1874) who made a new species of the causal organism under the name of Tylenchus millefolii. He dealt with the appearance, size and distribution of the galls, their presence on plants from spring to autumn and the ability of the parasite to revive from galls which had been kept dry from May to October. He described the general structure of the adult worms, gave particulars of their size and proportions, and, in addition to a sketch of a galled leaf, gave a drawing of the adult female and three views of the male tail.

The muscular distribution of Trichinella spiralis or T. britovi was studied by digestion in 59 experimentally infected pigs and seven wild boars. Crus muscle was the predilection site in 89.3% of 28 heavily infected swine with 146–3634 larvae per gram (lpg), but in 51.6% of middle to light infections (0.005–59 lpg) the basis of the tongue showed higher larval densities than the crus muscle. The basis of the tongue was also the predilection site in 71.4% of wild boars. Highest counts in other muscles were found only in lightly infected pigs. The influence of intensity of infection, host species, and Trichinella species on muscle distribution is discussed.

Nine helminth parasites were used as biological tags to discriminate diverse areas of Scomber colias Gmelin, 1789. During three seasons, a total of 369 fish were examined in four zones off the Tunisian coast, including Bizerte in the north, Kelibia and Mahdia in the centre and Zarzis in the south. Discriminant analyses were used to identify distinct areas of S. colias. Fish from Bizerte were grouped as one area and were correlated negatively with the monogenean Grubea cochlear and the digenean Lecithocladium excisum. Specimens from Kelibia and Mahdia were grouped together and were characterized by the ectoparasite Pseudokuhnia minor and by endoparasites Prodistomum orientalis, Monascus filiformis and anisakid larvae. Fish from Zarzis were grouped as one area and were positively correlated with the monogenean G. cochlear and the digenean L. excisum. These results were corroborated by comparing the prevalence and mean abundance of parasites among zones. Results of other discriminant analyses used for the classification of S. colias between localities after pooling specimens from the central areas of Kelibia and Mahdia also allowed the identification of three distinct areas: one in the north, correlated negatively with G. cochlear and L. excisum; one in the centre, characterized by P. minor, P. orientalis, M. filiformis and anisakid larvae; and one in the south, from Zarzis, characterized by G. cochlear and L. excisum. Results of comparisons of infection parameters between seasons and those of seasonal discrminant analyses showed a seasonal stability of communities from the northern and the southern areas. Specimens from the central regions showed variability between seasons, suggesting migratory movements.

In the present study, phylogenetic relationships of European and Far Eastern representatives of the genus Aspidogaster Baer, 1827 were analysed: A. conchicola Baer, 1827, A. limacoides Diesing, 1834, A. ijimai Kawamura, 1915 and A. chongqingensis Wei, Huang & Dai, 2001. Based on ITS1–5.8S–ITS2 rDNA sequence data, an obvious differentiation was seen between specimens of A. limacoides sensu stricto from the European part of Russia and A. limacoides sensu Chen et al., 2010 from China (13.7%); the latter parasites were recognized as A. chongqingensis. Aspidogaster chongqingensis was more closely related to A. ijimai than to A. limacoides s. str. Specimens of A. ijimai from the Amur River, Khanka Lake (Russian Far East) and China were grouped into a single clade with low intra specific molecular differentiation (d = 0–0.3%). Specimens of A. conchicola from the European part of Russia, the Russian Far East and China also formed a single distinct clade. Genetic differentiation between European and Chinese samples of this species was two times lower (d = 0.45%) than between Russian Far East and European or Chinese samples (d = 0.96%), suggesting a long-term separate existence of A. conchicola in the Russian Far East.

A further modification of a lung perfusion technique was evaluated by examining the recovery rate of 14-day-old Dictyocaulus viviparus worms from the excised lungs of 15 dead bovine calves. Up to 89% of the total number of worms found in 12 l of perfused fluid was recovered in the first 4 l collected. The application of this observation will increase the efficiency of the routine laboratory diagnosis of D. viviparus infection.

Thometrema magnifica from Hypostomus commersoni and Loricariichthys anus (new host) is redescribed with additional morphological data and original figures, measurements and figures of Szidat's paratypes. Gibson & Bray's hypothesis that T. portoalegrensis is its synonym is confirmed.

In the Pampa region of Argentina, farming activities have been performed since the beginning of the 20th century, but in the 1990s, land-use patterns rapidly changed towards intensive agriculture and poultry breeding. This study compares the helminth community of Akodon azarae (Rodentia) among three habitats with different land use in pampean agroecosystems: poultry farms, mono-cultivated fields and abandoned fields (not used for 35 years), under the prediction that there will be greater helminth richness and diversity in mice from abandoned fields compared to those from the other habitats. Nevertheless, the highest abundance of A. azarae occurred on poultry farms, the habitat most disturbed by human activity, while cultivated fields showed the lowest. Helminth richness and diversity were significantly higher on poultry farms than in the other habitats, due to the presence of Trichuris laevitestis, Protospirura numidica criceticola and cysts of Taenia taeniaeformis. We suggest that the helminth fauna of A. azarae can survive on poultry farms despite disturbance from farming activities, because rodents can move and get shelter within farm perimeter fences, where dense and high vegetation grows. This farm area could offer good conditions for geohelminth development, while chicken sheds could attract insects that are intermediate hosts of helminths with indirect life cycles. On the contrary, agrochemicals applied in cultivated fields would negatively influence helminth diversity and composition, by decreasing host populations (arthropods and rodents) and affecting free larval stages of geohelminths.

This study presents a list of parasitic fish nematodes from the Brazilian Amazon based on the previous Brazilian list including scientific assessments carried out between 2010 and 2021. A total of 16 families, 48 species and 28 undetermined species of nematodes associated with fish are included in the checklist, in addition to 93 host species and 15 geographical records.

Neoechinorhynchus is one of the most speciose genera of acanthocephalans, with approximately 116 described species. A recent study, aimed at establishing the genetic diversity of Neoechinorhynchus in Middle American freshwater fishes, validated nine species molecularly and morphologically and revealed the existence of 10 putative candidate species. Neoechinorhynchus golvani, a parasite commonly found in cichlids throughout Middle America with an allegedly large intraspecific morphological variability, was found to represent a species complex; species delimitation methods uncovered three additional genetic lineages. Here, we re-analyse the morphological and molecular data for N. golvani species complex infecting cichlids in that geographical area. A multivariate analysis of variance (MANOVA) was conducted particularly for the length of apical, middle and posterior hooks of the species/lineages of Neoechinorhynchus in cichlids, revealing morphological variation in the length of apical hooks for Lineage 8, although no morphological distinction was observed for Lineages 9 and 10. A new concatenated phylogenetic analysis of one mitochondrial and two ribosomal DNA genes was used to further corroborate the species delimitation among lineages; Neoechinorhynchus Lineage 8 was found to be morphologically and genetically distinct from its sister taxa, N. golvani and other two undescribed genetic lineages, and is formally described as a new species. Neoechinorhynchus costarricense n. sp. is described from the intestines of eight species of cichlids in Costa Rica. The new species is distinguished from the other species/lineages of Neoechinorhynchus in cichlids mainly by the size of the apical hooks of the proboscis.

In order to identify types of forage that inhibit pasture contamination, an evaluation was performed of the effect of the forage legumes Trifolium repens (white clover), Trifolium pratense (red clover) and Lotus corniculatus (bird's-foot-trefoil) on the survival and migration of infective larvae (L3) of gastrointestinal nematodes (GIN) of sheep. An experimental area of 441 m2 was divided into four blocks, subdivided into areas of 1.20 × 1.20 in which the three forage legumes were separately overseeded. After growth of the forage in each subdivision, experimental units were established that were later artificially contaminated with sheep faeces containing GIN eggs. Between October and December 2018, pasture, faecal and soil samples were collected on four occasions during weeks 1, 2, 4 and 8 after the deposition of faeces. In week 6, the forage legumes in all the experimental units were mown to simulate grazing. The number of L3 was quantified to determine their survival in the pasture, faeces and soil. In addition, the horizontal migration of L3 was measured at two distances from the faecal pellets (10 and 30 cm), as well as their vertical migration at two heights of the plant stems, that is, lower half and upper half. Larvae vertical migration was affected by the forage species (P < 0.001), in that bird's-foot-trefoil contained fewer larvae in the upper stratum. Bird's-foot-trefoil restricted the migration of L3 to the upper stratum of the plant, which could potentially decrease the risk of infection by intestinal nematodes in grazing sheep.

A study of the distribution and population of Lymnaea gedrosiana in relation to the transmission of Ornithobilharzia turkestanicum in various habitats was carried out in Khuzestan.

Populations were higher in canals and swamps than in ponds, with peaks in spring and autumn and low densities in summer and winter.

The reproductive capacity of L. gedrosiana was higher in running water than in stagnant water. The peak reproduction rates occurred in spring and autumn and reproduction continued at a low level in summer but was nil in winter.

Infection with O. turkestanicum was higher in large than in small snails (0.1 %, 0.5% and 1.1% in snails measuring 0.6 mm, 6–10 mm and 10–14 mm respectively). In canals and swamps transmission occurred throughout the year, with a peak in late summer in the former and early summer in the latter. In ponds, most transmission probably occurred in spring and autumn. Drains played a very minor role in transmission.