Gyrodactylus sphinx Dmitrieva & Gerasev, 2000 is the only species of Gyrodactylus originally described from Aidablennius sphynx (Valenciennes) in the Black Sea. In the present study, monogeneans similar to G. sphinx are reported from the same host and from two other species of Blenniidae from the Black Sea, as well as from the Mediterranean Sea. This study aims to verify the taxonomic status of the specimens found in different hosts and localities, other than the type ones of G. sphinx. Twenty-two measurements of the haptoral structures of 169 gyrodactylids were used for the morphological study. Morphometric variability between different samples was analysed using analysis of variance, multivariate analysis of variance (MANOVA) and principal component analysis (PCA). Molecular studies were carried out using the nuclear internal transcribed spacer 2 and 5.8S ribosomal DNA regions. Network, Bayesian phylogenetic and species delimitation analyses were performed to infer the number of taxonomic units and the phylogeographic relationships occurring within and among them. MANOVA revealed a significant dependence of the morphometry of hamuli and marginal hooks on host species and regions, but a clear differentiation between samples was not confirmed by PCA. Moreover, the ranges of all dimensions overlapped between samples. However, molecular analyses suggested the occurrence of at least two taxonomic entities. The most common entity was present in individuals of the Black and Mediterranean seas, and is described here as Gyrodactylus gerasevi n. sp., whereas a second entity recognized as a G. sphinx was found only in individuals from two localities off Crimea. The monophyletic cluster grouping of these two species was placed within a large clade that also included a separate sister cluster with seven other species of the Gyrodactylus orecchiae cross-ocean species group.

Thus far, high burdens of Triaenophorus crassus plerocercoids have been reported only in old age groups of coregonid and salmonid fishes. Here we show heavy infection with T. crassus in young whitefish Coregonus lavaretus in the ultra-oligotrophic and regulated Achensee in Tyrol, Austria. Prevalence of T. crassus on C. lavaretus was 100% in all age groups and abundance significantly increased with fish age. The mean annual accumulation of T. crassus was 5.2 parasites in 0- to 7-year-old C. lavaretus, and 2-year-old specimens already harboured a mean of 19.4 plerocercoids. In Arctic charr Salvelinus umbla, however, the prevalence of T. crassus was less than 16% and the majority of infected fish contained only one or two plerocercoids. Triaenophorus nodulosus was present neither in C. lavaretus nor in S. umbla. We assume that the heavy T. crassus infection in C. lavaretus is largely related to their zooplankton-dominated diet and to the characteristics of Achensee, while habitat choice and feeding strategy of the S. umbla population are seen to be the main reasons for their low burdens of T. crassus.

At the post mortem examination of a Saddle-billed Stork which died at the London Zoological Gardens, filarial worms were found in the heart and pulmonary artery. These parasites were forwarded for identification to Prof. R. T. Leiper, to whom I am indebted for the opportunity of examining and reporting upon the filariid and for assistance regarding the relevant literature.

This study examined sequence variability in internal transcribed spacers (ITS) of nuclear ribosomal DNA among Syphacia obvelata and Aspiculuris tetraptera isolates from laboratory mice from different geographical locations in China. ITS1, 5.8S and ITS2 rDNA were amplified separately from adult S. obvelata and A. tetraptera individuals by polymerase chain reaction (PCR), and the amplicons were subjected to sequencing from both directions. The lengths of the sequences of ITS1, 5.8S and ITS2 rDNA from both nematodes were 314 bp and 456 bp, 157 bp, and 273 bp and 419 bp, respectively. The intraspecific sequence variations in S. obvelata ITS1 were 0–0.3%. For A. tetraptera they were 0–0.7% in ITS1 and 0–1.0% in ITS2. However, the interspecific sequence differences among members of the infraorder Oxyuridomorpha were significantly higher, being 54.0–65.5% for ITS1 and 55.3–64.1% for ITS2. Phylogenetic analysis based on the combined partial sequences of ITS1 and ITS2 using three inference methods – Bayesian inference, maximum likelihood and maximum parsimony – revealed that all the S. obvelata and A. tetraptera samples formed independent monophyletic groups. Syphacia obvelata was closer to Syphacia muris than to A. tetraptera, consistent with morphological classification. These results demonstrate that ITS1 and ITS2 rDNA sequences are useful markers for population genetic studies of oxyurid nematodes.

Three digeneans – Parahemiurus merus (Linton, 1910), Aphanurus stossichii (Monticelli, 1891) and Lecithochirium sp. – and one tetraphyllidean cestode larva were used as biological tags to discriminate the stock of Sardinella aurita (Valenciennes, 1847). In total, 579 fish were examined in five zones off the Tunisian coast, including Bizerte and Kelibia in the north, Mahdia in the east, Gabes and Zarzis in the south. Discriminant analyses used for the separation of S. aurita allowed for the identification of two discrete stocks. Sardinella aurita from Bizerte, Kelibia and Zarzis clumped together as a single stock. Parahemiurus merus and A. stossichii were the most important species in determining the location of sampled fish from these regions. Specimens from Mahdia and Gabes were grouped as one stock characterized by the presence of Lecithochirium sp. and larvae of the Tetraphyllidea. These results were corroborated by comparing the parameters of prevalence and mean abundance of parasites among zones. The separation of S. aurita between localities after pooling specimens from Bizerte, Kelibia and Zarzis and separately pooling those from Mahdia and Gabes also allowed the identification of two discrete stocks, one in offshore waters from Bizerte, Kelibia and Zarzis characterized by the digeneans P. merus and A. stossichii and one in inshore waters from Mahdia and Gabes characterized by Lechithochirium sp. and tetraphyllidean larvae.

It is a common view that assemblages of parasitic nematodes are influenced by climatic conditions; however, there are only a few articles available regarding those that infect farm animals. We investigated the relationship between climate variables and infection with abomasal trichostrongyles in 335 1-year-old rams grazed on steppe pastures in Eastern Algeria. Abomasa were collected from 12 local slaughterhouses located in four climatic areas (from humid to arid) and the worms extracted, identified and counted. The abundance was low and the fauna composed primarily of Teladorsagia circumcincta, Marshallagia marshalli and Trichostrongylus sp. The high percentage of M. marshalli is typical of steppe areas. Ostertagia ostertagi and Haemonchus contortus were present in low numbers. Rainfall was the most important climatic variable related to the main species. This relationship was not linear for M. marshalli but an optimal rainfall was detected (350–400 mm/year). The more complex climatic indicators used in the study did not demonstrate a more significant correlation than rainfall. The predictive value of rainfall on the abundance or proportion of species in the assemblage was modest but highly significant. The seasonality of assemblages was different between the two main sub-climates (sub-humid and semi-arid).

The objective of this study was to evaluate the anthelmintic efficacy of Iris hookeriana Linn. rhizome against gastrointestinal nematodes of sheep. A worm motility inhibition assay was used for in vitro study and a faecal egg count reduction assay was used for an in vivo study. The in vitro study revealed anthelmintic effects of crude aqueous extracts and crude ethanolic extracts on live Trichuris ovis worms (P ≤ 0.05) as evident from their paralysis and/or death at 8 h after exposure. The aqueous extracts of I. hookeriana resulted in a mean worm motility inhibition of 54.0%, while ethanolic extracts resulted in a mean worm motility inhibition of 84.6%. The mean mortality index of aqueous extracts was 0.55, while for ethanolic extracts it was 0.85. The lethal concentration 50 for aqueous extracts was 0.45 mg ml− 1 and for ethanolic extracts it was 0.15 mg ml− 1. The in vivo anthelmintic activity of aqueous and ethanolic extracts of I. hookeriana in sheep naturally infected with mixed species of gastrointestinal nematodes demonstrated a maximum (45.62%) egg count reduction in sheep treated with ethanolic extracts at 2 g kg− 1 body weight on day 10 after treatment, closely followed by ethanolic extracts at 1 g kg− 1 body weight on day 10 after treatment (43.54% egg count reduction). The aqueous extracts resulted in a maximum of 31.53% reduction in faecal egg counts on day 10 after treatment with 1 g kg− 1 body weight. Thus ethanolic extracts exhibited greater anthelmintic activity under both in vitro and in vivo conditions; this could be due to the presence of alcohol-soluble active ingredients in I. hookeriana. From the present study it can be suggested that I. hookeriana rhizome exhibited significant anthelmintic activity against gastrointestinal nematodes of sheep and has the potential to contribute to the control of gastrointestinal nematode parasites of small ruminants.

Bimiracidial infections of Lymnaea truncatula with three isolates of Fasciola gigantica, originating from China, Egypt and Madagascar, were carried out to determine the effect of geographic origin of the parasite on the larval productivity of redial generations. The prevalences of experimental infections in snails exposed to strains from Madagascar, China and Egypt were 20.8%, 60.0% and 80.0%, respectively. At day 49 post-exposure (p.e.), the total number of free rediae in snails infected with the Egyptian isolate was significantly higher than that recorded in the Madagascan group. On the other hand, at day 49 p.e., the majority of cercariae in the Chinese and Egyptian groups were produced by R2a rediae (70.6% and 66.6% of cercariae produced by all live rediae), while, in the Madagascan group, the cercariae were produced mainly by the first redial generation. Snails infected with the Egyptian isolate of miracidia developed more live rediae and, consequently, could produce a higher number of cercariae. As a result, L. truncatula snails were highly adapted to infections with the Egyptian and Chinese isolates of F. gigantica.

Orthocoelium streptocoelium is a common paramphistome species parasitizing the rumen and/or reticulum of small ruminants, leading to significant losses. This study first determined the complete mitochondrial (mt) genome of O. streptocoelium. The complete mt genome of O. streptocoelium was amplified, sequenced, assembled, analysed and then compared with those of other digeneans. The entire mt genome of O. streptocoelium is 13,800 bp in length, which is smaller than those of other digeneans except for Opisthorchis viverrini. This mt genome contains 12 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and two non-coding regions. The arrangement of the O. streptocoelium mt genome is the same as those of other digeneans except for Schistosoma haematobium and Schistosoma spindale. Phylogenetic analyses based on concatenated amino acid sequences of the 12 protein-coding genes representing 16 digeneans were conducted to assess the relationship of O. streptocoelium with other digeneans. The result indicated that O. streptocoelium is closely related to Paramphistomum cervi and Fischoederius elongates, which is in accordance with their relationships by taxonomy. This complete mt genome of O. streptocoelium enriched the mitochondrial genome data of paramphistomes and provided important molecular markers for diagnostics and studies of population variation, epidemiology, ecology and evolution of O. streptocoelium and other digeneans.

Eight species (four new) of Urocleidoides are reported from Characiformes and Gymnotiformes fishes of the coastal drainages of the Eastern Amazon. Urocleidoides vanini n. sp. is characterized by having a male copulatory organ (MCO) with three and a half counterclockwise rings, absence of vaginal sclerite, and a V-shaped ventral bar. Urocleidoides atilaiamarinoi n. sp. has MCO with two and a half counterclockwise rings, dumbbell-shaped accessory piece, similar anchors, open V-shaped ventral bar, and open U-shaped dorsal bar. Urocleidoides macrosoma n. sp. exhibits an elongate and robust body, MCO comprising one counterclockwise ring, similar anchors with wavy point, and dumbbell-shaped ventral and dorsal bars. Urocleidoides nataliapasternakae n. sp. has MCO comprising two and a half counterclockwise rings, vaginal canal convoluted, point of the dorsal anchor with ornamentation as sclerotized shredded filaments, elongate dumbbell-shaped ventral bar, and U-shaped dorsal bar. Urocleidoides naris and Urocleidoides brasiliensis from H. malabaricus (Characiformes) and the incertae sedis species, Urocleidoides gymnotus and Urocleidoides carapus, from Sternopygus macrurus (Gymnotiformes) are reported, and their molecular sequences are presented in this study. Phylogenetic analyses based on molecular data (28S rDNA and COI mtDNA) reveal that species of Urocleidoides lacking vaginal sclerite are closely related to species that possess vaginal sclerite, suggesting that the absence of vaginal sclerite in Urocleidoides may be the result of a secondary loss. The relationships between species of Urocleidoides and other Neotropical dactylogyrids are also addressed.

Among fish parasitic nematodes Rhabdochona is one of the most speciose genera, with c. 100 species. Twelve congeneric species occur in Mexican freshwater fishes, in a region located between the Nearctic and Neotropical biogeographical regions. Host association and biogeographical history have determined the high species richness of Rhabdochona in Mexico. One of these species, Rhabdochona mexicana, is highly specific to the characid genus Astyanax. Characids are a group of freshwater fish with Neotropical affinity. In this paper, we explore the genetic diversity of R. mexicana through samples obtained from populations of Astyanax spp. across river basins of Mexico and Guatemala. Sequences of one mitochondrial and two ribosomal genes were obtained from 38 individuals and analysed using Maximum Likelihood and Bayesian Inference analysis. Phylogenetic analyses using cox1, and a concatenated alignment of 18S + 28S + cox1 recovered two genetic lineages. One of them corresponded with R. mexicana sensu stricto; this lineage included three reciprocally monophyletic subgroups; the other lineage was highly divergent and represented a putative candidate species. A detailed morphological study was conducted to corroborate the molecular findings. We describe a new species herein and discuss the implications of using molecular tools to increase our knowledge about the diversity of a speciose genus such as Rhabdochona.

Inorganic analysis of Ascaridia galli has shown the levels of sodium, potassium, copper, magnesium, calcium, zinc, iron, nitrogen, phosphorus, sulphur, chlorine and cobalt (expressed as percentage of dry weight) to be higher in females than in males.

Several female specimens of a new Philometrid nematode were collected by the writer from under the skin of the fish Bagrus bayad (Forskal) in the head region, just lateral to the sides of the mouth opening. The worms could be seen with some difficulty under the skin, and each fish harboured 2–4 worms. About thirty per cent of the fishes examined were infected and the parasite was prevalent from the month of December to the end of February or early March only.

Two new species of spiruroid nematodes in birds from Kangean Island, Indonesia are reported: Diplotriaena anthreptis sp. nov. is found from the abdominal cavity of Anthreptes malacensis malacensis. The new species is similar to D. ozouxi, D. bargusinica, D. delta, D. isabellina and D. obtusa in the size of tridents and the length of spicules. However, it differs from the five similar species in the structure of the tridents, in the morphology of the right spicule, in the spicule ratio and in the size of the eggs. Acuaria irhami sp. nov. is described based on two male specimens from under the gizzard lining of Dicrurus hottentottus jentincki. The new species can be distinguished easily from all congeners except from A. microecae, in having equal rather than subequal or dissimilar spicules. However, the new species can be differentiated from A. microecae in the number of postanal papillae, in the median preanal papilla and in the length of the cordons.

Haemonchus contortus is a major parasite of small ruminants and its blood-feeding behaviour causes effects ranging from mild anaemia to death. Knowledge of the genetic variation within and among H. contortus populations can provide the foundation for understanding transmission patterns and aid in the control of haemonchosis. Adult male H. contortus were collected from three geographical regions in Egypt. The second internal transcribed spacer (ITS2) of nuclear ribosomal DNA was amplified using the polymerase chain reaction (PCR) and sequenced directly. The population genetic diversity and sequence variations were determined. Nucleotide sequence analyses revealed one genotype (ITS2) in all worms, without genetic differentiation. The similarity in population genetic diversity and genetic patterns observed among the three geographical regions could be attributed to possible movement between the sites. This is the first study of genetic variation in H. contortus in Egypt. The present results could have implications for the rapid characterization of H. contortus and other trichostrongyloid nematodes, and evaluation of the epidemiology of H. contortus in Egypt.

Schistosomiasis is a chronic debilitating parasitic disease that causes hepatic damage and is known to be endemic in developing countries. Recent control strategies for schistosomiasis depend exclusively on chemotherapeutic agents, specifically praziquantel. Unfortunately, praziquantel has low efficacy in the early phase of infection, and resistance to treatment is increasingly reported. The aim of this work was to find an alternative treatment by assessing the in vivo activity of aqueous extract of Callistemon citrinus against Schistosoma mansoni in both prepatent and patent phases in experimentally infected mice. The study was conducted on 80 male BALB/c albino mice divided into eight groups. Callistemon was administered at a dose of 200 mg/kg on days 14 and 45 post infection as a single therapy and in combination with praziquantel. Porto-mesenteric worm burden, hepatic and intestinal egg counts, hepatic granuloma number and diameter, and oogram pattern were assessed to evaluate the anti-schistosomal properties of C. citrinus. Liver enzymes and total bilirubin were tested to assess hepatoprotective effects. Results revealed that the use of C. citrinus was associated with a significant decrease in worm burden and tissue egg load together with an increased percentage of dead eggs. In addition, there was a significant reduction in granuloma formation. Callistemon also led to a significant improvement in liver function. The best results were obtained when C. citrinus was given in the prepatent phase of infection and when combined with praziquantel. Although the effects of C. citrinus are considered to be promising, further studies using different extracts, active ingredients and doses are needed.

The establishment, growth, survival and distribution ol Hymenolepis muris-sylvaticae m different laboratory animals (Wistar rats, golden hamsters, CFLP and NMRI mice) after oral infection and surgical transplantation were determined.

Worms that establish in CFLP and NMRI mice grow exponentially but are rejected at different times p.i. depending on the strain of mice and mode of infection. Only in golden hamsters will H. muris-sylvaticae develop to a mature worm; in rats there is no growth at all. Worms of all sizes are found in the posterior half of the small intestine in rats and both strains of mice; in hamsters the worms are recovered more anteriorly.

The nematode Trichostrongylus longispicularis was described by Gordon (1933) from a single male recovered from a sheep in New South Wales. Gordon considered that the male of this species could be readily distinguished from the males of other species of the genus recorded from ruminants by an asymmetrical dorsal ray of the bursa and by the length and form of the spicules. The dorsal ray is described as being bifid, one bifurcation being simple and the other possessing secondary branches, one situated internally and the other externally. The slender spicules were 184·6 microns long, and terminated in fine sickle-shaped structures.

Andrews (1934 and 1935) recorded the species from cattle in the United States. In his first description (Andrews, 1934) he noted that his specimens agreed very closely with the description published by Gordon (1933), but he referred to hook-like projections on the spicules. However, he failed to find these projections in the specimen discussed in his record of 1935. As he made no reference to the dorsal ray of the bursa, it is presumed that this agreed with the description and figure published by Gordon (1933). T. longispicularis was subsequently reported by Roberts (1938 and 1939) from cattle in Queensland, but no comments were made on its morphology.

In the course of an examination of unidentified Zoological material in the London School of Hygiene and Tropical Medicine, I recently came across a species of filarial worm from the portal vein of a North American Snake, Coluber melanoleucus, which I name Macdonaldius seetai n.g., n.sp.

Experimental investigations of the subcutaneous infection of third-stage larvae of Nippostrongylus brasiliensis reveal discrepancies between the actual and intended inoculum, and also variability between replicate inocula. Emphasis is thus placed on the importance of obtaining accurate estimates of the level of confidence associated with inoculum size. Under specified laboratory conditions, the retention of infectivity of N. brasiliensis larvae was found to be age-dependent, with a maximum of between 120 and 156 days. The motility of the larvae was not found to be indicative of their ability to complete migration and to become established in the small intestine of the host following subcutaneous inoculation.