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.

Analysis of mitotic and meiotic chromosome spreads of Aspidogaster conchicola (Trematoda: Aspidogastrea) reveals a diploid number of 10 for this species. Haploid sets containing 5 bivalents confirm the diploid number. The karyotype consists of one pair of comparatively long subtelocentric chromosomes and four pairs of shorter acrocentric elements. The results are discussed in comparison with existing data on chromosomes of aspidogastrean species and other related helminth groups.

Dirofilaria repens is a zoonotic mosquito-borne filarioid that parasitizes in the subcutaneous tissues of carnivores, that has been incriminated in the great majority of human dirofilariasis cases reported throughout the Old World. From the Republic of Uzbekistan, recent data showed that this parasite is endemic in domestic and wild carnivores. In contrast, information regarding human infection is scarce and mostly outdated, with a single case report being published during the last decades. The present paper reports a case of recurrent autochthonous infection with D. repens in a patient living in the rural area of the Sirdaryo Region of Uzbekistan and having no international travel history. The first diagnosis was in 2019, when the patient presented with what was suspected to be a tumour of the left breast. Three years later, in 2022, she presented for a consultation after experiencing redness, occasional swelling and persistent itching in the umbilical region of the abdomen. The ultrasound indicated the presence of a living, motile nematode. Following anthelmintic therapy, the parasite was surgically removed and identified as a female D. repens. The present report highlights the possibility of human re-infection with D. repens and further underlines the necessity of raising public awareness and implementing of solid control strategies in carnivores.

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.

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.

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.

Two specimens of this fluke were collected from the nictitating membrane of the Steppe Eagle, Aquila nipalensis Hudson, shot near the lake Chinhut, about 5 miles from Lucknow, U.P.

The body.(Fig. 1) is aspinose, flattened and clavate with a narrow anterior and a broadly rounded posterior end. It measures 4·5–5·9 mm. in length and 1·5–1·8 mm. in maximum width in the middle region. The oral sucker is terminal measuring 0·33–0·36 mm. X 0·47–0·49 mm. The ventral sucker is larger than the oral sucker, situated at the level of the division of. the anterior and middle-thirds of the body, and about 1·14 mm. from the anterior extremity. It measures 0·56–0·61 mm. X 0·52–0·54 mm.

The protein composition of various developmental stages of Dipetalonema viteae was analysed on polyacrylamide slab gels in the presence of sodium-dodecylsulphate. When the total proteins of adult male and female parasites, microfilariae, eggs, and third-stage larvae were compared, apparent qualitative similarities between mature and immature filariae were observed. However, several stage specific components were also identified.

Pyridoxine (vitamin B6) deficiency was induced in cotton rats which were then infected with the filarial parasite Litomosoides carinii. Embryogenesis was assessed microscopically in worms taken from pyridoxine deficient cotton rats and from various categories of control animals. Embryogenesis was retarded in worms from pyridoxine deficient hosts and more abnormal embryos were present in such worms than in those from control animals.

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.

Morphological variations in Onchocerca armillata and O. gutturosa, from buffalo and cattle, with special reference to male tail and cuticular ornamentation, have been studied from a large collection of worms available from the infected aortae and ligamentum nuchae, procured from slaughter houses at 3 different localities in Uttar Pradesh, India. Seven variations in the disposition of caudal papillae in males in O. armillata and 14 in O. gutturosa are described. The prevalence of these two Onchocerca species in bubaline and bovine populations appears to be widespread.

It was shown that maintenance of cercariae of S. mansoni and S. haematobium at low (10°C) and high temperatures (40°C) markedly increased their mortality during penetration of mammalian host skin. These increased losses in the skin accounted for the known decrease in infectivity, as measured by adult worm recovery, of cercariae kept at low or high temperatures.

The yellow-necked mouse, Apodemus flavicollis, can be considered as a model for genetic polymorphism produced by the frequent presence of supernumerary or B chromosomes (Bs). Host genetic background is rarely taken into account in studies of parasite sex ratio. The main aim of this study was to investigate the range of infrapopulation sex ratios for nematode parasites of the yellow-necked mouse and to determine which factors most influence variation in parasite sex ratios. Six nematode species found in the collected yellow-necked mice were analysed. We confirmed the predominant pattern of female-biased sex ratios in vertebrate parasite infrapopulations. The presence of B chromosomes in host genomes played an important role in infrapopulations of Heligmosomoides polygyrus, Syphacia stroma and Trichuris muris, as hosts with B chromosomes carried a higher proportion of males. The relative increase of males in infrapopulations could result from a shift in parasite life history strategy, induced by adaptation to the specific host genotypes (Bs present). In a meta-analysis with previously published data, the sex determination system was demonstrated to play a significant role in nematode sex ratio variation, as well as specific life history patterns, such as the place of egg hatching.

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.

The Indian gerbil, Tatera indica indica, was collected in the arid western Rajasthan at Bikaner during the first weeks of July, August and September 1968. From sixty gerbils a large number of nematodes belonging to the genera Streptopharagus Blanc, 1912, Rictularia Froelich, 1802 and Trichuris Roederer, 1761, together with a few cestodes, were recovered from the stomach and intestine. The Streptopharagus sp. described below, vastly outnumbered the other worms and appears to be a new species.

During the summer of 1961 an opportunity arose which enabled us to study the incidence of certain helminth parasites in pigs slaughtered at Roath Abattoir, Cardiff. The studies were undertaken primarily because of the apparent lack of incidence figures concerning the helminth parasites in pigs from the southern part of the Principality. Some information was available for other regions of the Principality as Morgan (1924), Jones (1926) and Lewis (1930) have published reports on helminth parasites of pigs from Central and North Wales. Unfortunately none of these papers provided any comparative data on incidence of the various helminths, the numbers of each species in each infection and the proportion of sexes for each helminth in a given population.

Exposure of encysted metacercariae of Clinostomum complanatum to UV light (254 nm) for 60 min reduced their development into adult worms in buff-backed herons (95.7% reduction in worm burden). Metacercariae that succeeded in developing into adult worms, showed low fecundity levels. Furthermore, 30% of eggs laid showed abnormal shape; however, all normal and abnormal eggs failed to hatch into miracidia. The effectiveness of UV-irradiated metacercariae as a vaccine was investigated. Compared to control unvaccinated herons, the vaccinated group showed a significantly high protection rate (73.8%) against challenge. In vitro, worm development after challenge showed decreased fecundity and increased egg abnormalities, where only 1.5% of all eggs produced hatched into miracidia. A passive haemagglutination test revealed increased antibody titres against soluble adult worm antigen in both vaccinated and vaccinated-challenged birds. It was concluded that vaccination of herons using encysted metacercariae UV-irradiated for 60 min can protect them against challenge infection.

1. Ten species of Capillaria are recorded from eight species of British birds. C. blomei from the pheasant and partridge and C. exilis from the rook are new host records.

2. The identity of C. reseda and the systematics of C. blotnei, C. bursata and C. caudinflata are discussed in the light of observations made upon material in the collection.