The adult of Clinostomum tilapiae n.sp. obtained from the buccal cavity and oesophagus of Bubulcus ibis 7½ days after experimental infection with metacercariae is described.

The metacercaria of C. tilapiae n.sp. from Tilapia zilli, T. heudeloti and T. galilaea is described.

Anatomical differences between metacercariae and adults of the species are listed.

A modification of the Kato thick smear technique, the Bell filtration technique, and a digestion method were investigated to determine the relative merits of each for the detection of schistosome eggs in human faecal samples. The modified Kato technique was the method of choice because it was sensitive, simple to perform, and suitable for field use. The Bell filtration technique was equally sensitive in detecting light infections, but was more tedious and more complicated to perform than the thick smear technique.

The value of the hanging-drop technique as used by Professor Buckley for the examination of the different views of the tip of tail and head of small nematodes is stressed. The spicules of various species of Enterobius have been examined with polarized light and the significance of the basal portion of the spicules is discussed.

E. vermicularis is recorded for the first time from the Chimpanzee(Anthropopithecus troglodytes), the Lar Gibbon of Malaya (Hylobates lar) and the Silky or Lion Marmoset (Leontocebus rosalia) all of which had been in the London Zoological Gardens for varying periods.

The hitherto unķnown male of E. anthropopitheci is described and the female is redescribed.

A new species, E. buckleyi from the Orang Utan(Pongo pygmaeus) is described.

A new species, E. lerouxi from the Gorilla(Gorilla gorilla) is described. This is the first record of an Enterobius from this host.

E. bipapillatus is described and recorded for the first time from the Guenon Monkey(Cercopithecus aethiops) from S. Rhodesia.

A new species, E. brevicauda is described from the Chacma Baboon(Papio porcarius) from S. Rhodesia. This is the first record of an Enterobius from this host.

Negative findings for Enterobius are recorded from ten postmortem examinations and fourteen NIH swab examinations of Rhesus Monkeys(Macaca mulata).

A new species, E. interlabiata is described from the Feline Douroucouli(Aotus felinus) from S. America. This is the first record of an Enterobius from this host.

In view of the criticism of Kreis (1932) the type and paratype material of E. atelis, E. lagothricis and E. duplicidens and some more recent collection of E. lagothricis have been re-examined and the findings of Cameron (1929) and Buckley (1981) confirmed.

The present study was carried out to determine the prevalence of gastrointestinal helminthiasis in ruminants in an irrigated area of lower Punjab (Pakistan). For this purpose, 100 faecal samples were collected from sheep, goats, cattle and buffaloes. Parasitological procedures including direct and indirect methods (sedimentation and floatation) and coproculture were used for the identification of helminths. The overall prevalence of helminthiasis was 51% in cattle, 47% in buffaloes, 62% in sheep and 52% in goats, with nematodes being the most common helminths. The prevalence of helminths was higher in young animals compared with adults in cattle (P < 0.0001), buffaloes (P < 0.0001), sheep (P < 0.059) and goats (P = 0.010). The prevalence of different species of helminths also varied in different age groups, with Toxocara vitulorum being higher in calves than adults both in cattle (P = 0.017) and buffaloes (P < 0.0001). Sex-wise prevalence of helminths was higher in males than females for buffaloes (P < 0.0001) and sheep (P = 0.014) in contrast to cattle and goats.

Populations of grey seals (Halichoerus grypus), sprats (Sprattus sprattus) and cod (Gadus morhua) in the Baltic Sea are relatively stationary. The present work, applying classical and molecular helminthological techniques, documents that seals and cod also share a common parasite, the anisakid nematode Contracaecum osculatum, which uses seals as the final host and fish as transport hosts. Sequencing mitochondrial genes (COX1 and COX2) in adult worms from seals and third-stage larvae from livers of Baltic fish (sprats and cod), showed that all gene variants occur in both seals and fish. Other anisakid nematodes Pseudoterranova decipiens and Anisakis simplex are also found in both seals and cod in the Baltic Sea, but at much lower rates. The Baltic grey seal population was left at a critically low level (comprising a few hundred individuals) during the latter part of the 20th century, but since the year 2000 a marked increase in the population has been observed, reaching more than 40,000 individuals at present. Ecological consequences of the increased seal abundance may result from increased predation on fish stocks, but recent evidence also points to the influence of elevated parasitism on fish performance. Contracaecum osculatum larvae preferentially infect the liver of Baltic cod, considered a vital organ of the host. Whereas low prevalences and intensities in cod were reported during the 1980s and 1990s, the present study documents 100% prevalence and a mean intensity of above 80 worms per fish. Recent studies have also indicated the zoonotic potential of C. osculatum larvae in fish, following the consumption of raw or under-cooked fish. Therefore the present work discusses the impact of parasitism on the cod stock and the increasing risk for consumer health, and lists possible solutions for control.

This paper summarizes the work of the Onchocerciasis Control Programme (OCP) in West Africa, a programme which over a 22 year history has reduced the public health problems of blinding onchocerciasis in eleven countries of West Africa through vector control and, more recently, ivermectin distribution. The paper emphasizes the different approaches to control the programme has developed in the different parts of the programme area which have been determined by the epidemiology of the disease (savanna/forest form), the migratory characteristics of the vectors, intensity of the disease before commencement of treatment, the combined impact of vector control and ivermectin and the likelihood of infiltration of infective blackflies from outside the programme area. The programme has constantly monitored the impact of operations on the trends in prevalence, incidence, annual transmission potential, ocular morbidity and species of fly populations, and as a result, has identified areas where special interventions are required until the programme comes to an end in 2002. The paper illustrates the changes in intensity of infection as measured by community microfilarial load and annual transmission potential over the duration of the programme control activities. The paper also defines and justifies the control strategies in different areas and identifies areas for special interventions.

Sequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 4 (nad4), and internal transcribed spacer (ITS) of rDNA among and within three cestodes, Spirometra erinaceieuropaei, Taenia multiceps and Taenia hydatigena, from different geographical origins in China was examined. A portion of the cox1 (pcox1), nad4 genes (pnad4) and the ITS (ITS1+5.8S rDNA+ITS2) were amplified separately from individual cestodes by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. While the intra-specific sequence variations within each of the tapeworm species were 0–0.7% for pcox1, 0–1.7% for pnad4 and 0.1–3.6% for ITS, the inter-specific sequence differences were significantly higher, being 12.1–17.6%, 18.7–26.2% and 31–75.5% for pcox1, pnad4 and ITS, respectively. Phylogenetic analyses based on the pcox1 sequence data revealed that T. multiceps and T. hydatigena were more closely related to the other members of the Taenia genus, and S. erinaceieuropaei was more closely related to the other members of the Spirometra genus. These findings demonstrated clearly the usefulness of mtDNA and rDNA sequences for population genetic studies of these cestodes of socio-economic importance.

There are about 70 species of capsalid monogeneans in the Benedeniinae worldwide but only about half are described from the diverse fish fauna in the Pacific Ocean. Up to 1992, only five species of benedeniines were known from Australia. Two potentially destructive species of benedeniines, Benedenia seriolae from Seriola lalandi and B. sciaenae from Argyrosomus hololepidotus from temperate Australian waters, are new host and geographic records for these monogeneans. A survey of some fishes from the Great Barrier Reef has revealed at least 15 undescribed species of benedeniines in addition to three species which have been described recently (B. lutjani, B. rohdei and Metabenedeniella parva). The few previous records for benedeniines from Australian fishes are probably the result of three factors. First, there have been relatively few careful studies of the external surfaces of fishes from Australia for monogeneans. Second, some benedeniines display a previously unsuspected specificity for particular external microhabitats on their hosts such as specific fins or sites previously unrecognized as microhabitats for monogeneans on the head of some species of fishes such as lip folds and branchiostegal membranes. Third, some benedeniines on the flanks and fins of some fish are extremely difficult to see because they are transparent and/or possess pigment spots throughout the body. Sometimes, benedeniines from colourful species of reef fish bear bright colours in their bodies. It is highly likely that these features serve as camouflage to conceal the parasites from predators such as cleaner organisms.

A comparative study was made of the occurrence of the metacercariae of Diplostomum spathaceum, Tylodelphys clavata and T. podicipina in the eyes of brown and rainbow trout, perch, ruffe, roach, ten-spined stickleback, eel and stone-loach, from Hanningfield Reservoir, Essex between January 1968 and March 1969. D. spathaceum was found in all fish species and T. clavata in all except eel and stone-loach. The degree of infection varied considerably between different host species. T. podicipina occurred mainly in young perch but was also found in rainbow trout and ruffe. D. spathaceum normally occurring in the lens was also found in considerable numbers in the humor of the eye in brown and rainbow trout, perch and ruffe. Infection with D. spathaceum and T. clavata increased with length and age of the host although in some host species there was a reduction in the largest fish examined. Newly introduced rainbow trout became infected with D. spathaceum and T. clavata during their first summer in the reservoir.

Experimental infections with strongyles were carried out using ponies reared worm-free. Infection with Strongylus vulgaris was produced by artificially administering larvae to housed ponies. Infection with small strongyles was produced both by this method and also by exposing hitherto worm free ponies to heavily infested pasture. The shortest prepatent periods found were: S. vulgaris, 149–156 days; Triodontophorus spp. and Poteriostomum spp., 63–70 days and trichonemid species 35–42 days.

It is now recognized that the morphospecies Anisakis simplex is not a single species but a complex composed of three sibling species, A. simplex sensu stricto, A. pegreffii and A. simplex C. In Japan, A. simplex-like larvae have been isolated from a variety of fish and humans, but the larvae collected have been identified as A. simplex by only light microscopy. Therefore, the epidemiology of the A. simplex complex, composed of three sibling species, is still unclear in Japan. In the present study, 26 A. simplex-like larval isolates were obtained from two Pacific cod landed in Hokkaido, Japan, and examined genetically by PCR–RFLP and direct sequencing of the ITS region of rDNA. Among the 26 isolates, 24 were identified as A. simplex sensu stricto, the other two as A. pegreffii. The present study is the first to confirm the distribution of A. pegreffii in Japan, and to detect A. pegreffii larvae in Pacific cod.

A rapid technique for the assessment of a larval population on herbage is presented. Factors influencing the reliability of this technique and the problems encountered whilst trying to estimate efficiency of recovery rate are discussed.

The swimbladder nematode Anguillicola crassus originates from Asia where it is a parasite of the Japanese eel Anguilla japonica. After its introduction to Europe about 25 years ago, the parasite spread rapidly within the indigenous populations of the European eel Anguilla anguilla and subsequently the prevalence and mean intensity appeared to stabilize. Under experimental and aquaculture conditions the naïve new host appears to be more susceptible to A. crassus compared to the original host. Both eel species develop a immune response against A. crassus. The antibody response is well characterized for the European eel, but poorly characterized for the Japanese eel. It remains unclear if antibodies have any protective function against A. crassus. Encapsulation of larvae of A. crassus can be observed in naturally infected European eels. However, encapsulation of larvae following experimental infection has not been detected in European eels, but only in Japanese eels. Reinfection experiments and intraperitoneal injection of A. crassus homogenates failed to demonstrate the development of acquired immunity in European eels. Immunization with irradiated third stage larvae provided preliminary evidence for acquired immunity against A. crassus in the Japanese eel, but not in the European eel.

This study focuses on the development of fibrosis of the liver of cattle with Fasciola hepatica infection, correlating with the intensity of infection. Animals with an established diagnosis of chronic F. hepatica infection were identified in a slaughterhouse in Lima, Perú. The study included 24 fresh cattle livers from infected animals and two uninfected controls. Tissues were stored at 4°C for approximately 8 h after which they were brought to a necropsy room and examined. Between 9 and 12 biopsies were randomly obtained from each liver. Histological staining of formalin-fixed liver sections with haematoxylin and eosin (H & E) and Masson's trichrome were performed. Liver samples were examined using a pathology protocol that included 30 items. Histopathologically, 16 out of 30 liver specimens (67.6%) showed diffuse fibrotic lesions (cirrhosis) with a mean number of Fasciola of 116 ± 30 (range 4–435). Pathological data were matched to number of adult parasites and presence of cirrhosis after being reviewed by two independent pathologists. There was concordance between the two pathologists (K = 0.72). The group with cirrhosis showed an average of 116 ± 30 adult parasites whereas the group not showing cirrhosis contained 56 ± 28 flukes (P = 0.2). To measure how number of flukes and diagnosis of cirrhosis are related we used Kendall's tau-b coefficient; the correlation was +0.296 (P = 0.04). Receiver Operating Characteristic (ROC) curve results showed that the best point was 38 parasite adults, which had 93.8% sensitivity and 75% specificity. We conclude that as the number of F. hepatica adult forms increases, the likelihood of developing liver fibrosis will also increase in cattle.

The influence of temperature and ultra-violet radiation on the degree of activity, survival and infectivity of schistosome miracidia is profound. Miracidia of Schistosoma mansoni and S. haematobium were affected equally. Only miracidia classified as “active” or “slow” were capable of penetration, a capacity they retained for about 17 hours at 19°C. Miracidia that were “lethargic” as a result of low temperature, old age or ultra-violet radiation lost their infective capacity. The conclusion, however, is that neither the temperatures encountered in the field nor the solar ultra-violet radiation penetrating turbid waters are likely to be harmful to miracidia and thus have no effect on the level of transmission.

A survey of the helminths of Scottish hill sheep, made by collecting over seven hundred viscera from sheep which died from disease or accidents on over eighty farms, has shown that worms are the direct or indirect cause of the death of many sheep, and of loss in condition of many more.

Infestations of H. contortus increase in incidence and severity in the late spring, but the majority of hill sheep are not infested with it and it is not a serious problem unless lack of herding, bad weather, etc. harm the sheep.

Ostertagia spp. are often the most numerous species found in Scottish hill sheep; their numbers increase considerably for several weeks in the spring and to a less extent and for a shorter time in the autumn. Any prophylactic dosing programmes for lambs, hoggs or adult sheep must include Ostertagia spp. in the species against which they are directed.

The numbers of T. axei increase in Scottish hill sheep during the winter and for some weeks from March onwards contribute to the pathogenic effect of clinical and subclinical helminthiasis of sheep.

The problem of the vector of Onchoccrca gibsoni was investigated in Kuala Lumpur, F.M.S., where the parasite is endemic and a high percentage of cattle is infected.

For reasons which are outlined, the experimental work was confined to species of Culicoides and Lasiohelea of which 18, possibly more, species were found on cattle, some of them being found to bite cattle in very large numbers daily.

The distribution of the microfilariae of 0. gibsoni in the skin of live cattle was found to be very irregular, even within small areas of skin. In transverse sections of skin the microfilariae appear to have a maximum concentration just under the epidermis at a depth of ·05 to ·2 mm.

0·52% of 1,523 Culicoides pungens, which were dissected soon after an infective blood meal, were found to have picked up the microfilariae. 0·96% of 1,670 of this species, dissected some days after an infective blood meal, were found to have developing or mature filarial larvae in the thorax or head. 0·35% of 3,734 of this species, were found to be naturally infected with filarial larvae in the thorax or head. The difference between the experimental infection rate and the natural infection rate is shown statistically to be significant and it is concluded that C. pungens is an intermediate host of O. gibsoni.

Culicoides oxystoma, C. shortti and C. orientalis were also dissected in large numbers and were found to pick up the microfilariae of O. gibsoni; in each of these species the experimental infection rate exceeded the natural infection rate, but the difference in none of these is significant. It is concluded however, from the results obtained and from the morphological similarity of the mature larvae found in these species with that in C. pungens, that these species are also intermediate hosts of O. gibsoni.

C. peregrinus and C. buckleyi are suspected but not proven intermediate hosts. C. anophelis and/or C. anophelisv. flavcscens and Lasiohelea stimulans were found to pick up the microfilariae but only partial development was found in them. C. sumatrae and C. raripalpis also picked up the microfilariae but no development was found in them. The remaining species worked with were entirely negative. In view, however, of the very minute percentage of infection which occurs in Culicoides spp. and the large numbers which must be dissected to obtain positive results, the negative results given by these less common species are not necessarily conclusive.

Acid-isolating and acid digestion techniques were used to recover the larvae of T. canis from the tissues of mice and the acid-isolating technique in particular proved to be an effective method.

1. 903 horses were examined at 3 abattoirs in South East England. 10(22–7%) of the horses at the London Colney abattoir, 23(13–9%) of those at the Braintree abattoir, Essex, and 90(12–9%) of those at the Islington abattoir, London, were infected with O. cervicalis. All 105 horses examined in Southern Ireland were found to be negative.

2. The adult worms of O. cervicalis were found without exception, in the ligamentum nuchae of infected horses. The suspensory ligaments of the fetlock and flexor tendons were always negative.

3. The microfilariae of O. cervicalis concentrate along the abdominal mid-line of the host. In 5 complete horse hides, 95% of the microfilariae were found within 6 inches of the linea alba. The examination of 31 other horses infected with O. cervicalis confirmed this pattern of microfilarial distribution.

4. The microfilariae were concentrated along the ventral mid-line, of the host; presumably an adaption to accommodate the habits of the vector C. nubeculosus, which bites preferentially in this area.

5. Seasonal variations in the number of microfilariae in horse skin, as reported by Japanese workers, was not observed. Evidence was found, however, to suggest that the microfilariae migrate into the deeper levels of the dermis during the Winter. Histological examination of infected horse skin showed that the microfilariae have a very uneven distribution in the dermis. They congregate together in isolated “clumps” or “nests” and are frequently found in close proximity to the sweat glands or hair follicles.

The activity, infectivity and fat content of ageing infective larvae of Ancylostoma caninum were investigated at regular intervals.

The reduction in activity and fat content was found to occur at a similar rate.