Microfilariae of Onchocerca volvulus were found in venous blood samples in 17 of 20 patients with moderate to severe ocular onchocerciasis in a Sudan-savanna focus in Cameroon. They were present in the urine in 7 of the 20 patients. The numbers of microfilariae increased during DEC therapy, both in the blood and urine, and they were not completely eliminated after 2 weeks of therapy.

Infective larvae of Dirofilaria immitis commonly escaped from the tips of the Iabella and rarely from the mid-portion of the labium of Aedes aegypti as they engorged blood or just probed on mice. During the infective feed a small quantity of liquid, not more than 1 µI in volume, accumulated around the emerging larvae. Liquid was never seen when uninfected mosquitoes engorged on mice. This fluid is of insect origin and probably haemolymph that exuded from the lumina of the labella or labium during worm emergence. The presence of the fluid prevents dessication of larvae on the surface of the skin and maintains them in a liquid medium until they enter the puncture wound that remains after withdrawal of the biting fascicle. The possible effects of the fluid on the geographical distribution of mosquito borne filariae are discussed.

Ring-necked pheasants were exposed to artificially limited 10-day infections with heterakids either from 0-10 or 10–20 days old. The number and length of worms developing from a subsequent challenge dose were compared with those in nonimmunized control birds and with those in birds that had been exposed to a continuous immunizing infection for a total of 49 days: 28 days before challenge and 21 days during the challenge infection.

Biochemical and histochemical techniques were employed to study tissue distribution, and concentrations of carbohydrate reserves and phosphatase activity in uninfected Mytilus edulis and specimens parasitized by Proctoeces maculatus. Glycogen was stored in the mantle, hepatopancreas, labial palps and mesosomal Leydig cells of the mussel, and in the body parenchyma of post-miracidial stages of the trematode. The glycogen content of the mantle and hepatopancreas increased steadily from January to a maximum level in June and then declined sharply to a minimum level in December. No differences were observed in the annual glycogen cycle of infected and uninfected mussels. Starvation of mussels at a temperature conducive to high metabolic activity of the worms resulted in a rapid decline in the glycogen content of infected mussels by the first week of starvation. A stable glycogen concentration was maintained for 4 weeks by starved uninfected mussels. The distribution of acid phosphatase activity in the tissues of M. edulis and P. maculatus was greater than that of alkaline phosphatase activity, but increased alkaline phosphatase activity was observed in the haemolymph of mussels infected with adult P. maculatus.

The tapeworm Spirometra theileri (Baer, 1925) n. comb., obtained as pleroccrcoids from a wart hog in Tanzania, has been maintained in the laboratory; adults in dogs, and larval stages in Cyclops and then rodents. The species differs physiologically and biologically from those described from other parts of the world in the cyclical production of eggs in dogs, inability of the procercoids to infect amphibia or reptiles, and the lack of any parasite-induced weight gain in mice, rats or hamsters.

Batches of 10 Anisakis larvae from Greenland salmon (Salmo salar) were labelled with radioiodcin and fed to 10 haddock (Melanogrammus aegiefimis). Similar batches of larvae from herring (Clupea harengus) were fed to 8 whiting (Merlangius merlangus). At post-mortem from 15 to 190 hours after infection, 0 to 6 larvae were recovered from whiting (over-all recovery rate 18.8%) and 0 to 4 larvae were recovered from haddock (over-all recovery rate 27%). Larvae penetrated the wall of the stomach or of a pyloric caecum. They were first seen in the body-cavity 24 hours after infection and a delicate capsule was present around some of them by 34 hours. Most larvae were recovered from the body-cavity but, in haddock, two had penetrated the epaxial musculature.

The effects of housing density on endocrine organ weights and on retention of the parasite Microphallus pygmaeus by male and female mice arc described. A reduction in gonadal function with increasing housing density was found in each sex. Male mice showed clear evidence of greater adrenocortical activity at higher densities but this was not as clearly defined in females. Animals of both sexes showed a decline in relative weights of both thymus and spleen at the highest densities. The number of parasites recovered, a standard time interval after introduction by stomach tube, was increased significantly in both males and females housed at higher densities. The results suggest that a progressive increase in population density in both male and female mice stimulates pituitary-adrenocortical activity and that there is concomitant suppression of gonadal function. The change in susceptibility to the parasites may also be a direct or indirect consequence of the change in pituitary-adrenocortical activity, on immunological responses or intestinal physiology, such as an increase in the duration of exposure to adverse pH values.

The morphology of abnormal development of the filarial worm Brugia patel in a mosquito host, Anopheles labranchiae atroparvus, is described. Development was very variable, from little growth beyond the microfilarial stage to the complete development of two infective stage larvae in one mosquito. The majority of larvae developed beyond the microfilarial stage but integrated differentiation did not occur. In the most bizarre larval development, the intestinal and the rectal cells prolapsed and then attempted to differentiate outside the body of the filarial larva. It is concluded that the abnormal development of the filarial larvae in this mosquito host is due to the host reaction elicited by the developing larvae, apparent as melanisation 48–78 hours after ingestion by the mosquito, often localised specifically over the excretory and anal vesicles.

The spatial distribution of the monogenean Dactylogyrus amphibothrium over the gill apparatus of the ruffe Gymnocephalus cernua was non-random, parasites being aggregated on certain areas of the gills. By plotting the distribution over the gills of the glochidia of Anodonta cygnea, the relative amounts of water passing over the different parts of the gill apparatus was determined experimentally. The observed distribution of D. amphibothrium was then compared with the distribution of the glochidia. The results obtained suggest that the site of attachment of D. amphibothrium is influenced at least in part by the direction and force of the respiratory current over the gills. Most parasites select a site where they are not subjected to its full force.

Autoradiographs revealed that sporocysts of Cercaria helvetica XII and rediae of Sphaeridiotrema globulus, incubated in a medium containing [14C]-glucose, exhibited slight radioactivity in their body wall after only 30 seconds incubation. Activity in sporocysts and rcdiae gradually increased as the incubation period was extended until after 4 minutes, a heavy reaction was observed in the parasite body wall as well as in the germ balls and developing cercariae within the parasite brood chambers. The redial caecum appeared to incorporate the labelled compound much more intensely than did the redial body wall.

When uninfected Bithynia tentaculata, as well as B. tentaculata infected with either S. globulus or C. helvetica XII, were maintained in pond water containing [14C]-glucose, activity could be detected in the gills of both infected and uninfected snails after 5 hours incubation. After 12 hours a much heavier labelling was apparent in the gills, together with moderate activity in the haemocoelic spaces, foot musculature, stomach wall, and gut contents. After 20 hours a more intense labelling was apparent in these regions of the snail body and, in addition, some activity could be detected in the digestive gjand tubules of the host and, in infected snails, in the bodies of developing parasites. After 30 hours incubation the labelled compound had become incorporated into most of the host tissues but was most intense in the digestive gland tubules. Heavy activity was also evident in the parasites at this stage although certain cystogenous gland cells of the cercariae of both parasite species did not incorporate the labelled compound.

A high incidence of lungworm infection occurs in young village pigs, 5 and 11 months old. The mean count was 215 and 315 adult lungwqrms for eleven 5 month and ten 11 month village pigs respectively. All infections were mixed infections comprising M. pudendodectis (69 %), M. apri (18 %) and M. salmi (13 %). No seasonal variation was observed in the rate of infection. A partial immunity to Iungworms is evident in the 11 month old pigs.

Using the indirect fluorescent antibody technique, the antibody response of cats to Brugia pahangi infections was studied using whole microfilariae and sectioned adult worms of B. pahangi as antigens. Microfilarial antigen was ineffective in detecting antibody response in cats during the microfilaraemic phase of the infection, although it was possible to detect circulating antibody in cats which became microfilaria negative after repeated and prolonged reinfection and in one cat which after infection failed to show microfilariae in its blood

The structure of the cuticle of third and fourth stage larvae and of adult Brugia pahangi (Nematoda: Filarioidea) was studied by light microscopy and by transmission and scanning electron microscopy. The cuticle of these worms was basically typical of the class Nematoda and consisted of cortical, matrix, and basal layers. Finely spaced annulation grooves were present and their function is discussed.

Descriptions of the cuticular ultrastructure of filarial nematodes are meagre. Studies on the cuticle of adult worms are limited to those of Kagei (1960, 1963) on Setaria cervi and Litomosoides carinii and of McLaren and Hockley (personal communication) who examined L. carinii and Dipetalonema vitea

In a survey of large intestine material from sheep in North East England, Trichuris ovis and T. skrjabini were recovered. This is the first record of T. skrjabini in Western Europe. The two species can be separated on the length, shape and degree of eversion of the spicule in the male, and on the type of vulval expansion, nature of the vagina and straight portion of the ovary in the female. The relative dominance of T. ovis compared with T. skrjabini in Britain may be attributable to the faster rate of development of the pasture stages of the former species.

The taxonomic histories of Spirometra and Lueheella are reviewed, and the former is shown to be a junior synonym of the latter. Gatesius probably has priority over both. It is suggested that the International Commission on Zoological Nomenclature be petitioned to exert their Plenary Powers to validate Spirometra and invalidate Lueheella and Gatesius.

Two new species of helminths, Fastigiuris prudhoei from Ochotona rufescens Gray, 1842, and Trichuris mofidii from Rhombomys opimus Lichtenstein, 1823, have been identified and described from mammals collected in Iran.

Two species of palaeacanthocephalan from Solea bleekeri from estuarine waters in Cape Province, South Africa, are described. Rhaidinorhynchus capensis sp. npv. differs from its closest relatives in having a smaller proboscis and in having body-spines arranged in a single field. Longicollum sp. innom., described from a single male specimen, differs from other species of the genus in having a basal row of large proboscis hooks and in having a recurved proboscis-sac.

The two species of palaeacanthocephalans described in this report were collected from Solea bleekeri Boulenger, 1898, in estuarine waters in the southern-most region of Cape Province and donated to the British Museum (Natural History) by Professor John H. Day of the Zoology Department, University of Cape Town. Co-infestations did not occur, nor were both species found in the same immediate geographical area. The coastal region of Cape Province, from Algoa Bay in the east, to Cape Agulhas or Cape Point in the west, constitutes, according to Ekman (1953), an independent zoogeographical province, and, therefore, data on the parasitic worms of the marine fish of this region, which at the moment are exceedingly meagre, may be of interest and importance as indicators of the affinities of the fish stocks inhabiting this area.

Breinlia mackerrasae n.sp. is described from the short-nosed bandicoot Isoodon macrourus. It bears most similarity to B. dentifera, but differs in having larger spicules and in the arrangement of the anal papillae. Female worms from a ‘mumut’ (Peramelidae) are described, but as no males are available, their taxonomic status remains uncertain. These are the first records of Breinlia from peramelid marsupials.

The morphology of Diplostomulum (Tylodelphylus) xenopodis Southwell and Kirshner, a strigeatoid metacercaria from the pericardial cavity of the African clawed toad, Xenopus laevis, is described and its systematic position discussed. The parasite has both a high incidence and intensity of infection in host samples from the Cape: 60% of 410 X. laevis examined carried D.(T) xenopodis and 26% of infected hosts harboured 100 worms or more. Parasite longevity in excess of 3 1/2 years was recorded in laboratory maintained toads and the effects of experimentation on the host are considered particularly in relation to parasite survival and pathogcnicity. Attempted maturation of the metacercariae in Anas and Larus species was unsuccessful; aspects of the biology of transmission of the parasite in the natural habitat are discussed.

Neoheterakis chapini n.g., n.sp. (Nematoda: Heterakoidea) is described from the caecum of a Congopeacock Afropavo congensis Chapin, 1936. The diagnostic features of the subfamily Spinaspidoderinae are extended to accomodate the new genus.