A data set on intestinal helminth parasites was collected in the course of an 18 year investigation into the biology of eels in Meelick Bay, Lough Derg, River Shannon. This was used to test two hypotheses relating to the composition and structure of intestinal helminth communities, namely that eels in large rivers do not harbour richer and more diverse communities than those in small rivers but that community composition and structure are more stable over time than in small rivers. The helminth community was species poor, with only six species comprising the component community and a maximum infracommunity richness of three species. The community was overwhelmingly dominated by the acanthocephalan Acanthocephalus lucii, reflecting the importance of its intermediate host Asellus aquaticus in the eels' diet. The remaining helminth species contributed to species richness but made very little contribution to community diversity. Population levels of Acanthocephalus lucii fell and remained low between 1992 and 2000, probably reflecting increased movement of eels from other parts of the lough into Meelick Bay. Diversity values were low, but similar to those reported from other rivers in Britain and Europe. The results provided support for both hypotheses and indicated that in respect of richness, diversity and dominance, the helminth communities of eels in the River Shannon were typical of, and comparable to, those of other large rivers throughout Europe.

In a revision of the genus Setaria s.l. the author gives a review of the literature on the systematics of this group. The genus Setaria s.l. is divided into three genera. Hyraconema n.g. monotypic for H. loveridgei (Sandground, 1928), a primitive worm of the hyracoids; Setaria Viborg, 1795, monotypic for S. equina (Abildg., 1789) the common parasite of equine animals; and Artionema n.g. for the remaining species, all of which occur in artiodactyls. Artionema africana n.sp. is the genotype. A. africana is found in Tragelaphus spp. and cattle in various parts of continental Africa. The other new species A. hartwichi n.sp. is found in the European deer, Capreolus and Alces on continental Europe. The paper includes a discussion on host parasite relationship, phylogeny and the evolution of taxonomic characters in speciation. In the Subfamily Setariinae Yorke and Maplestone, 1926, the author recognizes five genera as follows: Skrjabinofilaria Trav., 1925; Hyraconema gen. nov., Setaria Viborg, 1795, Papillosetaria Vevers, 1923 and Artionema gen. nov. The paper ends with a host list.

Acanthocephalan ova, indistinguishable from the ovoid eggs of Moniliformis moniliformis, were detected in the stools of a 45-year-old man at the University of Jos Health Clinic. Nigeria. The patient complained of general body weakness, occasional giddiness and intermittent burning sensations around the umbilicus. Successful treatment with niclosamide and the possible source of infection are communicated.

The purpose of this paper was to discuss from an evolutionary perspective the interaction between domestic sheep (Ovis aries) and their gastrointestinal nematodes. Although evolution is the central theme of biology, there has been little attempt to consider how evolutionary forces have shaped and continue to shape the relationships between domestic animals and their parasite community. Mathematical modelling of the host–parasite relationship indicated that the system is remarkably robust to perturbations in its parameters. This robustness may be a consequence of the long coevolution of host and parasites. Although nematodes can potentially evolve faster than the host, coevolution is not dominated by the parasite and there are several examples where breeds of cattle or sheep have evolved high levels of resistance to disease. Coevolution is a more equal partnership between host and nematode than is commonly assumed. Coevolution between parasites and the host immune system is often described as an arms race where both host immune response genes and parasite proteins evolve rapidly in response to each other. However, initial results indicate that nematode antigens are not evolving rapidly; the arms race between the immune system and nematodes, if it exists, is happening very slowly. Fisher's fundamental theorem of natural selection states that genes with positive effects on fitness will be fixed by natural selection. Consequently, heritable variation in fitness traits is expected to be low. Contrary to this argument, there is considerable genetic variation in resistance to nematode infection. In particular, the heritabilities of nematode-specific IgA and IgE activity are moderate to high. The reasons for this apparent violation of the fundamental theorem of natural selection are not clear but several possible explanations are explored. Faecal nematode egg counts increase at the beginning of the grazing season – a phenomenon known as the periparturient rise. This increase benefits host and parasite and appears to be a consequence of coevolution. In conclusion, an evolutionary perspective can shed light on many aspects of the host–parasite relationship in domestic animals.

The study was conducted to determine the sequence variation in two mitochondrial genes, namely cytochrome c oxidase 1 (pcox1) and NADH dehydrogenase 1 (pnad1) within and among isolates of Toxocara cati, Toxocara canis and Toxascaris leonina. Genomic DNA was extracted from 32 isolates of T. cati, 9 isolates of T. canis and 19 isolates of T. leonina collected from cats and dogs in different geographical areas of Iran. Mitochondrial genes were amplified by polymerase chain reaction (PCR) and sequenced. Sequence data were aligned using the BioEdit software and compared with published sequences in GenBank. Phylogenetic analysis was performed using Bayesian inference and maximum likelihood methods. Based on pairwise comparison, intra-species genetic diversity within Iranian isolates of T. cati, T. canis and T. leonina amounted to 0–2.3%, 0–1.3% and 0–1.0% for pcox1 and 0–2.0%, 0–1.7% and 0–2.6% for pnad1, respectively. Inter-species sequence variation among the three ascaridoid nematodes was significantly higher, being 9.5–16.6% for pcox1 and 11.9–26.7% for pnad1. Sequence and phylogenetic analysis of the pcox1 and pnad1 genes indicated that there is significant genetic diversity within and among isolates of T. cati, T. canis and T. leonina from different areas of Iran, and these genes can be used for studying genetic variation of ascaridoid nematodes.

Measured dosages of larvated eggs of the caecal nematode, Heterakis gallinarum and the small intestinal nematode, Ascaridia galli were fed to domestic chickens, in order to study the distribution of the numbers of worms developing and the influence on the worms and the chicks of the treatments in the experiments. These treatments are summarised in Table 1, p. 110.

Chronic respiratory disease, accidentally acquired by the groups of chicks in varying degrees appeared to have no influence on the course of the worm infections and the ensuing blackhead (Table 2, p. 112).

Following ingestion of eggs of Heterakis, blackhead occurred in three of four groups of chicks, apparently in varying degrees, possibly related to the size of the egg dosage and to differences in susceptibility to Heterakis (Table 1, p. 110). The chicks inthe group which did not contract blackhead were considerably older than those of the other groups.

The increasing prevalence of anthelmintic-resistant strains of helminths, drug residues in animal products and high cost of conventional anthelmintics has created an interest in studying medicinal plants as an alternative source of anthelmintic. The potential nematicidal activities of four extracts from the bark of Canthium mannii (Rubiaceae) stem were investigated in vitro. Extracts were diluted in distilled water (DW) to obtain five different concentrations (1.5, 2.0, 2.5, 3.0 and 3.5 mg/ml) and put in contact with eggs and larvae of Heligmosomoides polygyrus. The different stages of the life cycle were also put in contact with the same concentration of mebendazole (MBZ, positive control). One millilitre of each extract at different concentrations and control were added to 1 ml solution containing 30–40 eggs or 10–15 larvae (L1, L2 and L3) and distributed in different Petri dishes. The eggs and larvae were incubated at 24°C and exposure times were: 48 h for un-embryonated eggs, 6 h for embryonated eggs; 2, 4, 6 and 24 h for L1 and L2 larvae, 24–48 h for infective larvae (L3), and 5 days for the larval development test (from L1 to L3). DW and 1% dimethyl sulphoxide (DMSO) were used as placebo and DMSO control, respectively. Significant effects were obtained with three of the four extracts, and differences were observed depending on the parasite stage. Cold water extract (CWE), hot water extract (HWE) and ethanol extract (ETE) inhibited embryonic development (40, 45 and 10%) and hatching of embryonated eggs (40, 85 and 80%), respectively, at 3.5 mg/ml. Only ETE killed L1 (97.18%) and L2 (92.68%) larvae of H. polygyrus after 24 h at 3.5 mg/ml and drastically reduced the production rate (6% at 3.0 and 3.5 mg/ml) of infective larvae (L3) after 5 days of incubation compared to other extracts (P < 0.05). However, the infective larvae of H. polygyrus were resistant to the effect of each of the tested products (extracts and mebendazole). These in vitro results suggested that extracts of C. mannii, used by traditional healers in Dschang, Western Region of Cameroon (Central Africa) to cure intestinal helminthiasis and abdominal pains of their patients, possess nematicidal properties. The active principles responsible for the activity could be secondary metabolites such as alkaloids and saponins present in the extracts. It is suggested that further experiments incorporating in vivo purification of extracts and toxicological investigations should be carried out.

The study evaluated the effect of storage time and conditions of nutritional pellets (NP) containing Duddingtonia flagrans chlamydospores on its in vitro trapping ability against Haemonchus contortus L3 larvae. The treated batch (200 NP) contained 4 ×  106 chlamydospores of the FTH0-8 strain, whereas the control batch (200 NP) was produced without spores. Both NP batches were exposed to four experimental storage conditions: (T1) shelves (indoors); (T2) refrigeration (4°C); (T3) outdoors under a roof; and (T4) 100% outdoors. Each group comprised 48 NP with spores and 48 NP without spores (control). The ability of D. flagrans spores to trap H. contortus L3 larvae was evaluated for 8 weeks for each storage condition. For that purpose, six randomly selected NP with spores were compared to their respective control NP. Each NP was individually crushed. The crushed material (1 g) was placed on the surface of a 2% water agar plate with 200 H. contortus L3 larvae. Plates were sealed and were incubated at room temperature for 8 days. The whole content of every plate was transferred to a Baermann apparatus to recover the remaining larvae. There was a clear larval reduction in the NP with spores, compared to the respective control NP in the four storage conditions (P< 0.05). The mean reductions ( ± SEM) of the storage conditions were 67 ± 4.9 (T2), 77 ± 6.1 (T1), 81.5 ± 3.8 (T4) and 82.1 ± 2.5 (T3). Larval reductions were similar at all times and were not affected by storage conditions or storage time (R2< 0.2; P>0.05). The long-term shelf-life of the chlamydospores in the NP suggests that this spore dosage technology is a viable option.

Hypodontus macropi Mönnig, 1929, is redescribed and its taxonomic affinities discussed. H. macropi is recorded for the first time from Wallabia bicolor, Macropus robustus, M. fuliginosus, M. dorsalis, M. agilis and Thylogale billardierii. The method of attachment of the parasite and gross and histopathological changes associated with it are described. Free living larval stages are described. Experimental infestations were attempted but were not successful. Hypodountus thetidis Johnston and Mawson, 1939, is made a synonym of H. macropi.

The two ascaridoids of sirenians, Heterocheilus tunicatus Diesing, 1839, and Paradujardinia halicoris (Owen, 1833), are redescribed. A basic affinity between the two species is indicated in the bilateral structure of the excretory system, the globular ventriculus, long intestinal caecum, and the form of the male tail. The subfamily Heterocheilinae is redefined so as to contain these two genera. It is proposed that the subfamily comprises a natural suprageneric group within the Ascarididae sensu Hartwich, 1974 containing, in addition to Heterocheilus and Paradujardinia, the following genera occurring in freshwater, estuarine and coastal vertebrates: Multicaecum Baylis, 1923; Dujardinascaris Baylis, 1947; Gedoelstascaris Sprent, 1978; Ortleppascaris Sprent, 1978; Brevimulticaecum Mozgovoy sensu Sprent, 1979; Krefftascaris Sprent, 1980. The suggestion is made that the ascaridoids of sirenians originated from forms in fluviatile lower vertebrates.

Oesophagostomum bifurcum larvae, cultured from human stools collected in northern Ghana, were used to establish experimental infections in monkeys. A patent infection was established in a rhesus monkey (Macaca mulatta) and this infection was used to generate larvae to inoculate additional monkeys. In all, 17 animals were inoculated. Thirteen of 15 animals developed antibodies to the infection between 19 and 62 days post inoculation (PI); two animals had a positive response before inoculation. Four of ten animals developed patent infections between 88 and 134 days and passed eggs in the faeces. Egg shedding was consistent in only one animal, but at low levels of one or two eggs per 2 mg direct smear, and extended over a 400 day period. In the other three animals, egg shedding was sporadic and of only 2–4 weeks duration. In seven animals necropsied between 19 and 22 days PI, one to 17 early fourth-stage larvae were recovered from nodules in the bowel wall; in an eighth animal examined at 314 days, six immature adult worms (early fifth stage) were recovered from nodules in the bowel wall. The morphological features and growth of these recovered larvae are described. Three animals were inoculated with larvae that had been dried for one week at 28°C; two animals began shedding eggs at 128 and 134 days PI, respectively. The present results suggest that the parasite obtained from humans is poorly adapted to lower primate hosts, and supports the concept that Oesophagostomum bifurcum found in humans and monkeys in the same geographical region of northern Ghana and Togo are distinct and that the infections in humans are not likely to represent zoonotic infections acquired from monkeys.

The life cycle of the heterophyid fluke, Haplorchis pumilio is elucidated for the first time from the Indian region. Various stages in the life cycle were established based on observations made on natural infections found in snails and fish in a freshwater stream at Visakhapatnam, India and experimental infections carried out in the laboratory. The thiarid snail, Thiara tuberculata served as the first intermediate host and a wide range of freshwater fish as second intermediate hosts. Natural infections with adult flukes were found in the piscivorous birds Ardeola grayii and Bubulcus ibis. Adults were raised experimentally in day-old chicks. Distinguishing features of the cercaria of H. pumilio are: a large body size (200–224×92–96 μm), body–tail ratio of 1:2.1 and densely distributed pigment granules in the parenchyma imparting a brownish tinge to the body. Natural infections with metacercariae were found in the freshwater fish Channa punctatus, C. orientalis, Puntius sophore, Gambusia affinis and fingerlings of Cyprinus carpio and Liza macrolepis. Additionally, experimental infections were established in Therapon jarbua, Esomus danricus and Oreochromis mossambica. Metacercariae were embedded in the caudal muscles of fish and heavy infections induced mortality. Metacercariae were infective at about 15 days of age.

In the course of work undertaken in the preparation of the experimental field plots at Winches Farm it has been of interest to ascertain something about the nematode fauna of the place, especially that occurring in certain heaps of manure made at the farm and afterwards used on some of the plots. With regard to the worms recorded from sheep droppings collected from pastures these were obtained in Baermann extractions, set up by a colleague, in attempts to collect larvae of parasitic nematodes harboured by the stock. It became necessary for purposes of differentiation to determine the naturally occurring free-living nematodes which were found in great abundance. The worms described in the following pages have been encountered in the course of these investigations. Some are new to science and about others very little has previously been known so that additional information on them is here made available.

Human Taenia solium cysticercosis is common in developing countries due to poor sanitary conditions and economics based on breeding livestock, especially pigs, with low hygiene standards. Neurocysticercosis, caused by migration of the larvae of the tapeworm in the nervous system, is the leading cause of acquired epilepsy in adults in Central and South America, sub-Saharan Africa, and East and South Asia. This makes neurocysticercosis a large public health problem in developing countries. Two clinical cases of neurocysticercosis have been observed recently in Haiti. In order to evaluate the prevalence of human T. solium cysticercosis in this country, in 2007 we conducted a cross-sectional serological retrospective survey using a Western blotting test (LDBIO Diagnostics®) in Port-au-Prince, where sewage systems are rare and swine usually roam freely throughout the area. A total of 216 serum samples, obtained from healthy adults seen in the work setting of periodical medical visits, were tested after storage at − 20°C. The frequency of antibodies in serum samples of the study population was 2.8% (6/216). The immunodominant bands recognized in Western blots were 23–26 kDa (100%), 39 kDa (67%), 45 kDa and 6–8 kDa (50%), 50–55 kDa (33%). These results confirm for the first time an endemic situation of cysticercosis in humans in Haiti, with similar prevalence as that reported in other Latin American and African countries. It reinforces the urgent need for control and prevention measures to be taken by local public health services.

A total of 142 serum specimens from Croatian children aged 3–18 years, with peripheral eosinophilia and without any clinical symptoms, were tested for the presence of Toxocara canis IgG antibodies using an enzyme-linked immunosorbent assay (ELISA) and Western blot method. The overall T. canis seropositivity rate in the samples tested was 31%. There was no statistical difference in the seroprevalence rate between boys (32.1%) and girls (29.7%, χ2 = 0.092, P = 0.761). The T. canis seropositivity varied significantly between age groups both in boys (Fisher's test P < 0.001) and girls (Fisher's test P = 0.007). The highest seroprevalence rate was found in boys aged 11–14 (42.9%) and girls aged 7–10 (44.2%). Our results showed a high seroprevalence rate of T. canis infection among children with eosinophilia. It is important that testing for toxocariasis should be included in a differential diagnosis of eosinophilia, especially in children.

The members of the nematode genus Rhabdias present many features of great interest to the parasitologist. They are usually found inhabiting the lungs of amphibians and reptiles where their eggs or larvæ are produced. They have the general appearance of females and are either hermaphroditic or parthenogenetic in function (vide Goldschmidt, 1923, p. 176, on “Unisexual Monœcism”). Seurat (1920), p. 121, considers that the parasitic forms of R. dujardini and R. entomelas from the Slow worm Anguis fragilis are parthenogenetic females and not protandrous hermaphrodites because they lay an enormous number of eggs, whereas the hermaphroditic forms produce comparatively few eggs. Moreover, in R. entomelas he has been unable to find either receptacula seminis or spermatozoa.

Populations of Egyptian spiny mice (Acomys cahirinus dimidiatus) in a fragmented montane wadi system in the Sinai showed significant differences in the abundance of gut helminths. Differences in parasite load between populations were positively associated with measures of androgen activity but showed no significant relationship with glucocorticoid activity. Social discrimination tests with adult males from different wadis showed that those from sites with greater helminth abundance were less likely to investigate odours from other males and were less aggressive when subsequently interacting with the odour donors. Subjects showed markedly more investigation towards the odours of males from distant wadis compared with those from their own or immediately neighbouring wadi, but were less aggressive when confronted with odour donors from distant wadis. Despite this, there was a positive relationship between the amount of investigation towards distant male odour and subsequent aggression towards the male. While aggressiveness was positively associated with measures of androgen and glucocorticoid activity, no significant relationship emerged with individual helminth infection. Thus aggressiveness appeared to relate to overall local population levels of infection rather than individual challenge.

1. Phase-contrast, ultra-violet and fluorescence microscopy have proved useful tools in the study of the embryology of filarial worms.

2. Spermatogenesis in L. carinii has been described for the first time for any filarial worm.

3. The spermatozoa of L. carinii and D. immitis are remarkable in that they contain well defined chromosomes.

4. The development of the ovum to the mature microfilaria has been described for both L. carinii and D. immitis.

5. Staining with acridine orange has demonstrated the cellular distribution of deoxyribonucleic acid (green fluorescence) and ribonucleic acid (red fluorescence) in both living and fixed embryos of each species.

The genus Sulcascaris is upheld and redefined. Sulcascaris sulcata from Chelonia mydas and Caretta caretta is redescribed, from Rudolphi's type material and material from the Mediterranean and Western Pacific, demonstrating that the excretory pore opens between the subventral lips and that the excretory cell is bilateral, comprising a short filamentar right component and a more capacious ribbon-like left component containing the nucleus. The phylogenetic significance of this form of excretory system occurring in an ascaridoid of a marine reptile is discussed. It is concluded from comparative studies, based on measurements, sections and electron scanning micrographs, that fourth stage larvae of S. sulcata collected from the stomach of turtles are identical with fourth stage ascaridoid larvae found in the adductor muscle of scallops (Amusium balloti and Chlamys sp.) and that turtles become infected with this species by eating bivalves. Adult S. sulcata were obtained from tank-reared C. caretta fed with encapsulated larvae from scallops.

Intestinal helminth parasites are responsible for a significant amount of pathology in both humans and farmed animals, resulting in a reduction in the quality of life, and occasionally lethal infection as well as causing decreases in livestock productivity. The importance of these parasites globally has resulted in efforts to understand the mechanisms of the host–parasite interaction epidemiology, and to develop methods for diagnosis and control.