The diagnosis of parasitic worm (helminth) infections requires specialized laboratory settings, but most affected individuals reside in locations without access to such facilities. We tested two portable microscopic devices for the diagnosis of helminth infections in a cross-sectional survey in rural Côte d'Ivoire. We examined 164 stool samples under a light microscope and then re-examined with a commercial portable light microscope and an experimental mobile phone microscope for the diagnosis of Schistosoma mansoni and soil-transmitted helminths. Additionally, 180 filtered urine samples were examined by standard microscopy and compared with the portable light microscope for detection of Schistosoma haematobium eggs. Conventional microscopy was considered the diagnostic reference standard. For S. mansoni, S. haematobium and Trichuris trichiura, the portable light microscope showed sensitivities of 84·8%, 78·6% and 81·5%, respectively, and specificities of 85·7%, 91·0% and 93·0%, respectively. For S. mansoni and T. trichiura, we found sensitivities for the mobile phone microscope of 68·2% and 30·8%, respectively, and specificities of 64·3% and 71·0%, respectively. We conclude that the portable light microscope has sufficient diagnostic yield for Schistosoma and T. trichiura infections, while the mobile phone microscope has only modest sensitivity in its current experimental set-up. Development of portable diagnostic technologies that can be used at point-of-sample collection will enhance diagnostic coverage in clinical and epidemiological settings.

The uniform morphology of the developmental stages of Haemogregarina species and the insufficient information supplied by the simplistic descriptions of previous authors complicates their differential diagnosis and proper species identification. In this study, we detected Haemogregarina spp. in 6 out of 22 (27·2%) examined turtles originating from Southeast Asia, Malayemys subtrijuga (n = 4), Sacalia quadriocellata (n = 1) and Platysternon megacephalum (n = 1), and compared them with the available literature data. Microscopic analysis of our isolates distinguished 2 morphological species, Haemogregarina pellegrini and one new species, being described in this paper as Haemogregarina sacaliae sp. n. Phylogenetic analyses based on 1210 bp long fragment of 18S rDNA sequences placed both haemogregarines firmly within the monophyletic Haemogregarina clade. Isolates of H. pellegrini from 2 distantly related turtle hosts, M. subtrijuga and P. megacephalum, were genetically identical. Despite the fact that numerous Haemogregarina species of turtles have been described, the incompleteness of the morphological data and relatively low host specificity provides the space for large synonymy within this taxon. Therefore, a complex approach combining microscopic analyses together with molecular-genetic methods should represent the basic standard for all taxonomic studies.

Plasmodium malariae, a protozoan parasite that causes malaria in humans, has a global distribution in tropical and subtropical regions and is commonly found in sympatry with other Plasmodium species of humans. Little is known about the genetics or population structure of P. malariae. In the present study, we describe polymorphic genetic markers for P. malariae and present the first molecular epidemiological data for this parasite. Six microsatellite or minisatellite markers were validated using 76 P. malariae samples from a diverse geographical range. The repeat unit length varied from 2 to17 bp, and up to 10 different alleles per locus were detected. Multiple genotypes of P. malariae were detected in 33 of 70 samples from humans with naturally acquired infection. Heterozygosity was calculated to be between 0·236 and 0·811. Allelic diversity was reduced for samples from South America and, at some loci, in samples from Thailand compared with those from Malawi. The number of unique multilocus genotypes defined using the 6 markers was significantly greater in Malawi than in Thailand, even when data from single genotype infections were used. There was a significant reduction in the multiplicity of infection in symptomatic infections compared with asymptomatic ones, suggesting that clinical episodes are usually caused by the expansion of a single genotype.

The cellular mucosal and systemic effectors of gilthead sea bream (GSB) (Sparus aurata) involved in the acute immune response to the intestinal parasite Enteromyxum leei were studied in fish experimentally infected by the anal route. In the intestinal inflammatory infiltrates and in lymphohaematopoietic organs (head kidney and spleen) of parasitized fish, the number of plasma cells, B cells (IgM immunoreactive) and mast cells (histamine immunoreactive) were significantly higher, whereas the number of acidophilic granulocytes (G7 immunoreactive) decreased, compared with non-parasitized and unexposed fish. These differences were stronger at the posterior intestine, the main target of the parasite, and no differences were found in the thymus. In non-parasitized GSB, the percentage of splenic surface occupied by melanomacrophage centres was significantly higher. These results suggest that the cellular response of GSB to E. leei includes proliferation of leukocytes in lymphohaematopoietic organs and recruitment into intestines via blood circulation involving elements of innate and adaptive immunity. Acidophilic granulocytes and mast cells presented opposite patterns of response to the parasite infection, with an overall depletion of the former and an increased amount of the latter. Some differences between both cell types were also detected in regard to their granule density and cell morphology.

The results are presented of an experimental investigation of the relationship between faecal egg counts and worm burden in outbred MF1 mice infected with Heligmosomoides polygyrus (Nematoda). The sex-ratio of the adult parasites was found to be significantly female biased, but independent of parasite burden. Evidence was also found to suggest a significant association between parasite density and mating success. The linear logarithmic relationship (gradient of approximately 2) between the variance and mean of repeated egg counts from individual mice could not be disrupted by controlled experimental conditions, and is therefore concluded to be an inherent feature of the biology of helminth-host interactions. A significant positive association was detected between host faecal output and parasite fecundity; further investigation of the cause of this association is now required. Average faecal production was found to be inversely related to worm burden. In combination, the above two factors account partly, but not completely, for the observed density dependence in the absolute rate of parasite egg production. Two epidemiological consequences of the relationship between faecal production and parasite fecundity are discussed. First, absolute rates of egg production can only be estimated by temporal egg counts (epd). Secondly, measurements of egg production/g of faecal material (epg) are more reliable indicators of worm burden than measurements of epd. Both faecal output and worm fecundity respond as might be predicted to a period of host food deprivation; faecal egestion and measurements of epd are signifcantly depressed, and measurements of epg are significantly increased. The data are consistent with the hypothesis that egg production and faecal output are causally associated, but that other factors relating to parasite density also influence egg production. Of the possible causes for the high variability in parasite egg production between mice harbouring low number of worms, the most likely explanation seems to be host heterogeneity (possible genetic in origin). This is discussed in relation to similar patterns observed in data collected from human populations in areas of endemic helminth infection.

A direct life-cycle in Reighardia sternae, a cephalobaenid pentastomid of gulls was investigated: the work was prompted by a report of eggs and larvae recovered from the stomach and intestine of a naturally infected gull.

Infective pentastomid eggs were obtained by surgically transplanting maturing female Reighardia, taken from freshly shot wild gulls, into captive recipients. Faecal material from birds thus artificially infected was collected daily and examined for eggs. Eggs were force fed to 33 hand-reared (from eggs or nestlings) juvenile gulls which were selected at random and sacrificed at intervals thereafter and examined for pentastomids.

One hour after infection, primary larvae appear in the body cavity where they moult immediately. They grow steadily and by 27–35 days are sexually differentiated, and by 66 days have copulated. Fertilized females take a further 116 days to produce eggs by which time they are 7·6 cm long.

The complex migrations undertaken by developing larvae in the gull, and the problems of the mechanism of direct transmission, are discussed.

The prevalence of the caecal threadworm Trichostrongylus tenuis in red grouse in the north of Scotland was high despite low grouse densities. Prevalence, intensity and aggregation of threadworms was higher in old than in young grouse. Infections were long-lasting: populations of adult worms could survive for over 2 years in grouse, with little mortality. Parasite egg output decreased with the age of a worm population, largely as a result of a decrease in the fecundity of ageing female worms. Seasonal variations in worm fecundity were also evident.However, there was no evidence of an intensitydependent decrease of worm fecundity with increasing worm numbers in either captive or wild grouse. The long life and high reproductive capacity of T. tenuis probably contribute to its effective transmission and high prevalence.

Rats thymectomized at birth were infected with Nippostrongylus brasiliensis at 6 weeks of age. In some, but not all, rats egg production was greatly prolonged after the primary infection. Thymectomized rats were less resistant than controls to second infections.

In rats infected at birth the development of resistance was significantly delayed. Neonatally infected rats, when they were 6 weeks old, were less resistant to reinfection than adult controls. Rats infected three times in the neonatal period were more resistant to challenge at 6 weeks of age than rats infected once at birth, but less resistant than adult controls. The degree of immunity induced by a single neonatal infection was variable; some rats showed little or no resistance to reinfection 6 weeks later.

Antibody formation, measured by the occurrence of reagins, was altered in the same way by both neonatal thymectomy and neonatal infection. In the thymectomized (immunologically deficient) and newborn (immunologically immature) rats, reagin formation following initial infection was delayed; there was a reduced anamnestic response after challenge; mean titres were lower and more variable than in control animals; and in some rats circulating reagins were never detected.

In thymectomized rats the capacity to demonstrate anaphylaxis was as variable as in control rats, but in the few thymectomized rats in which egg production was prolonged, anaphylaxis was slight at a time when most intact rats had developed the capacity to show anaphylaxis. Rats infected at birth and adult rats infected at the same time were equally susceptible to systemic anaphylaxis 6 weeks later, although by this time there was a marked difference in the degree of resistance to the parasite developed by the two groups.

In adult rats splenectomy before, during or after initial infection had no effect either on the rate of development, or the degree of immunity induced by primary or secondary infections, or on antibody formation.

We would like to thank Miss W. Griffiths and A. J. Edwards for their willing technical assistance. This work was done whilst one of us (B.M.O.) was the holder of a Wellcome Fellowship of the Animal Health Trust.

Of 414 Bermuda fishes, 148 belonging to 13 species harboured Digenea and 11 belonging to 6 species Aspidogastrea, Acanthocephala or nematodes. In a previous paper 69 of these fishes belonging to 20 species were found to contain cestodes. The number of infected species was greatest in the case of cestodes and the number of infected individuals in the case of Digenea. The latter is probably due to the closer proximity, for reasonably long periods, of the various hosts in the life-cycles. Of the 17 species of Digenea 3 are new host records, 3 new locality records and 4 new host and new locality records. New records were found, also, in the other groups of helminths. The digenean fauna of Bermuda fishes most closely resembles that of Dry Tortugas, Florida. Digenea and cestodes were not usually found in the same families of fishes. Cestode larvae were abundant in the deep-water Serranidae and Lutianidae which had no Digenea, the latter being common in Clupeidae, Hae-mulidae and Belonidae, which do not harbour cestodes and which occur, mostly, in the inner reefs and shallows.

The functional morphology of the apical disk, tentacles and rhynchus of Alcicornis carangis is described. The tentacles are invaginable and concerned with attachment.

I am most grateful to Dr W. H. Sutcliffe Jun., Director of the Bermuda Biological Station, for the excellent facilities provided and to The Shell Grants Committee and The National Science Foundation for grants which made the work possible. I would also like to express my gratitude to all those who kindly helped in the capture of fishes and to Mrs M. Fisher for technical assistance.

The relationship between changes in the temperature of storage of infective O. cuniculi larvae and the proportion that become inhibited in a subsequentinfection was studied. Prolonged storage at 5°C resulted in an initial inhibitionfollowed by acclimation to this temperature and subsequent normal developmentin the host. After acclimation to low temperature raising the temperature ofstorage produced no appreciable increase in the proportion of worms inhibited atthe early 4th stage. Maintenance of infective larvae at 15°C followed by a suddendecrease in storage temperature to 5°C resulted in rapid onset of inhibition. This inhibition was not reversed even after 25 days at the lower temperature. These temperature variations and the consequent pattern of arrested development werecompared to seasonal changes of spring and autumn occurring to nematode larvaeon pasture. An increase in the number of larvae given from 5000 to 15000 perrabbit had a slightly significant effect upon the proportion that remained inhibited. The need for careful assessment of the methods used for determining the extentof such inhibition is discussed.

Of two groups of calves, one was regularly treated with the cortisone-derivative, β-methazone. This treatment greatly reduced the ability of the calves to produce antibody and gave rise to a number of side effects. Calves of both groups were given 1500 infective larvae of Ostertagia ostertagi daily. A milder régime of cortisone administrations using prednisolone was employed in a second experiment in which two comparisons were made. Worm burdens of calves infected with 1500 larvae daily and receiving cortisone were compared with those of control calves infected at the same rate and cortisone-treated calves receiving 1500 larvae per day were compared with cortisone-treated calves infected at twice this rate.

By periodic post-mortem examination it was shown that even in cortisone-treated animals the worm burden was regulated at a level only slightly higher than in control calves, apparently by a density-dependant loss of worms. A more rapid loss of worms which occurred for a period in the control calves was prevented in cortisone-treated animals unless the infection rate was high.

The limit set by the normal host to the total egg output of its worm population was raised by cortisone treatment, very greatly in the first experiment, rather less in the second in which the cortisone treatment was less severe. The effect of host resistance on the length of worms and on the incidence of females without vulval flaps was greatly reduced by cortisone. The inhibition of development was not affected.

This study describes morphological changes during capsule formation of Trichinella spiralis with emphasis on nuclei within the capsule. The nuclei of the pre-existing muscle cell may become hypertrophied or degrade soon after the entrance of newborn larvae. Cytoplasm associated with these hypertrophied nuclei was basophilic in H&E staining and composed of mitochondria and rough endoplasmic reticulum. Satellite cells underwent cell division and joined to the nurse cell. These nuclei may also become hypertrophied or degrade. Cytoplasm associated with nuclei of satellite cell origin was eosinophilic in H&E staining and composed of mitochondria, polysomes, and smooth and rough endoplasmic reticulum. Eosinophilic cytoplasm (of satellite cell origin) became prevalent in the capsule as capsule formation proceeded. Infiltrated cells were observed within the capsule. Thus this study showed diversity of nuclei in the capsule of Trichinella.

Variation in the immunogenicity of 3 isolates of Trichinella spiralis was assessed by the parameters of adult worm recovery, mast cell, eosinophil and antibody responses in mice of defined response phenotype. The levels of the protective, inflammatory and immune responses induced by infection differed between the isolates. Isolates showed considerable variation in the capacity to elicit mast cell and eosinophil responses. All induced increases in parasite-specific antibody, levels of total (IgGAM) antibody and of IgM and IgG isotypes rose steadily after infection, but there were significant differences in levels of response. The IgGAM response was correlated with the number of worms present, i.e. the greatest response was seen in low responder (C57BL/10) mice infected with the longest-surviving isolates. All isolates elicited specific IgG1 and IgG2a antibodies after infection, although, again, there were isolate-specific differences in the levels and kinetics of response. Levels of these isotypes were always higher, although not significantly so, in high-responder NIH mice. Low-responder mice showed higher IgE serum levels than high-responder mice after infection, one isolate giving much higher IgE values than the other two.

1. Neodiplostomum intermedium Pearson is recorded from four new hosts; as an adult from the water rat, Hydromys chrysogaster Geoffroy, and as a metacercaria (diplostomulum), from tadpole and adult of an undescribed tree frog, Hyla sp., tadpole of (Hyla latopalmata (Günther) Mixophyes fasciolatus Günther and frog of an unidentified leptodactylid.

2. The life cycle of Neodiplostomum intermedium was followed experimentally; the hosts were: Pettancylus assimilis (Petterd), a fresh-water limpet, as first intermediate host; tadpole of Hyla pearsoni Copland as second intermediate host; Hyla caerulea (Shaw) a tree frog, and Hemisphaerodon gerrardi Peters, the pinktongued skink, as paratenic hosts; and Rattus assimilis (Gould) and laboratory rats as definitive hosts.

3. Descriptions are given of the morphology of the miracidium, mother sporocyst, daughter sporocyst, cercaria, and diplostomulum, with special reference to the structure of the miracidium and of the cercarial tail.

4. Observations are given on the embryology of the miracidium, hatching of the egg, transformation of the miracidium into the mother sporocyst with special reference to the germinal cells, the route and manner of escape of cercariae from the snail host, the development of the diplostomulum with special reference to the reserve excretory system, and the movements of diplostomula during metamorphosis of the tadpole host.

5. The haploid chromosome number is ten, as determined from squashes of testes. One paratype and a series of experimental adults have been compared with and found different from Neodiplostomum (Fibricola) sarcophilus n.comb. The orthography and formal proposing of the names of the species of Fibricola transferred to Neodiplostomum by Pearson (1959b) are corrected.

The writer wishes to thank Dr M. J. Mackerras, Queensland Institute for Medical Research, for generously supplying water rats; Professor J. F. A. Sprent, University of Queensland Veterinary School, for his criticism of the manuscript; Mr K. Webber and his sons for their assistance in catching rats and for permission to collect snails, frogs and tadpoles from their streams; and Mr R. J. Ballantyne for technical assistance. This study was supported by a grant from the Rural Credits Fund of the Commonwealth Bank of Australia.

The behaviour of oncomiracidia of the monogenean skin parasite Entobdella soleae, after hatching without chemical stimulation, has been studied in vertical, 4 cm high chambers illuminated from above. Most freshly hatched larvae are photo-positive and swim to the top of the vessel, where they remain actively swimming. Occasionally larvae become photo-negative and make a brief excursion to the bottom of the vessel. As the larvae grow older, these photo-negative excursions become more frequent and larvae spend progressively longer in the photo-negative phase of behaviour, but, even after many hours, photo-positive vertical excursions are still occurring. If this pattern of alternating photo-positive and photo-negative vertical movements occurs in the natural environment, these vertical movements, coupled with horizontal transport of larvae by water currents, would provide a search pattern for the host, the diurnally-inactive, bottom-living flatfish Solea solea. When eggs are stimulated to hatch in the chambers with urea, large numbers of larvae emerge within a few min, and it was observed that during the period of about 30 min after stimulation, many larvae are photo-negative. When eggs on the sea bottom are stimulated to hatch by mucus or urine from a nearby host, such behaviour would greatly enhance chances of contact with the fish. When eggs are stimulated to hatch by means of urea in the absence of light, there is evidence that the oncomiracidia are geo-negative. It has been shown that larvae are able to extricate themselves in total darkness from sediment containing buried eggs and that, in an experimental situation illuminated only by an infra-red beam, larvae readily attach themselves to the lower skin of soles within 2 min of hatching. There is evidence that, in aquaria, some invasion of the host takes place from below.

Babesia vesperuginis is described from blood of two species of British bat: Pipistrellus pipistrellus and Myotis myslacinus. Reticulocytes appeared significantly elevated in blood films of P. pipistrellus infected with B. vesperuginis compared with uninfected laboratory-maintained bats or apparently uninfected wild-caught bats. Infected captive bats had significantly enlarged spleens. B. vesperuginis was transmitted by inoculation of infected blood to 5 uninfected captive P. pipistrellus. The course of infection followed a pattern of a rising parasitaemia accompanied by a rise in reticulocytes, followed by a fall in parasitaemia to low (<0·1%) or undetectable levels. When sacrificed, the Babesia-infected bats had significantly lowered blood haemoglobin, significantly raised white blood cell counts and enlarged spleens compared to uninfected bats. Attempts to transmit the parasite to irradiated and athymic ‘nude’ mice by inoculation of infected blood were unsuccessful. The experimental results and observations of infected wild bats indicate the potential pathogenicity of B. vesperuginis to bats. It is likely that the vector of B. vesperuginis is Argas vespertilionis because no Ixodid ticks were found on P. pistrellus.

1. Ixodes holocyclus is a three-host tick.

2. It is found on native mammals, being abundant on Perameles nasuta (the bandicoot), while it has also been found on dogs, cats and man, and exceptionally on the large bush opossum and the rat.

3. Eggs hatch in from 49–61 days in warm weather.

4. Larvae harden and become active in about seven days, and engorge on host in 4–6 days.

5. Larval metamorphosis is prolonged by cold, and is most rapid in warm weather, varying from 19–41 days.

6. Nymphs harden and are quiescent for about seven days, and engorge in 4–7 days.

7. Adults emerge from larval skin in 21–71 days.

8. Coupling occurs away from the host and may last 11 days.

9. Adults harden and seek the host in about seven days and engorge in from 6–21 days.

10. Males are only rarely found on hosts, and have never been found attached or showing signs of engorgement.

11. Oviposition begins 11–20 days after the female leaves the host, and may last from 16–34 days; the number of eggs laid being about 1800–2500.

12. All stages are soon killed by desiccation, gorged nymphs and larvae being very soon killed even at moderate temperature.

13. A mass infestation with Ixodes holocyclus has not been seen either on native or domesticated animals.

The relationship between cell-mediated granulomatous inflammation and transmission of disease in schistosomiasis and tuberculosis has been explored. In 2 experiments involving Schistosoma mansoni-infected normal and T cell-deprived mice, and infected deprived mice that had been variously reconstituted with immune or normal lymphocytes or immune serum, there was a significant positive numerical correlation between mean liver granuloma diameters and faecal egg counts in individual animals. Lymphocytes from donors with recently patent infections were more active than cells from chronically infected or uninfected donors in reconstituting egg excretion rates in deprived recipients, and mesenteric lymph node (MLN) cells were more active than spleen cells. Modulation of granulomatous activity with increasing chronicity of infection in the donors, resulting in a decrease in granuloma size around freshly produced tissue-bound eggs, was paralleled by a waning of the capacity of transferred lymph node cells to reconstitute egg excretion in the recipients. Serum taken from chronically infected donor mice over the same period and transferred to infected deprived recipients became more active in enhancing egg excretion in the recipients as the cell-mediated activity declined. A recent study in Kenya has found that S. mansoni-infected patients with concurrent human immunodefficiency virus (HIV) infection excrete fewer eggs than patients exposed to the same levels of schistosome infection, but who are not HIV-infected, thus indicating that schistosome egg excretion in humans is also immune-dependent. Attention is drawn to an apparently parallel situation in human tuberculosis, another pathogen which induces a cell-mediated granulomatous immune response. Several studies have shown that patients with tuberculosis who are also HIV-seropositive tend to have fewer tubercle bacilli detectable in their saliva than those with tuberculosis, but who are HIV-negative. This discrepancy, associated with differences in lung pathology in HIV-positive patients, suggests that in tuberculosis immune cell-mediated granulomatous inflammation causes the destruction of host tissue in a manner which facilitates onward transmission of the bacterial pathogen.

As a subject of investigation the Trematode fauna of British Birds does not appear to have aroused at any time much enthusiasm amongst British zoologists and as a result we owe the greater part of our knowledge of the subject to continental workers. The fact that our bird fauna is practically identical with that of the adjacent parts of Western Europe would lead us to expect that the parasites of our birds should not differ materially from those met with in the same species of birds on the continent. As a matter of fact, no species of bird Trematode hitherto recorded from this country can be regarded as peculiar to Britain, with the possible exception of Echinostephilla virgula Lebour, which, however, will almost certainly be met with in other localities later.

The effects of a range of FMRFamide-related peptides (FaRPs) on isometric contractility were tested using isolated muscle strips from the liver fluke, F. hepatica. The neuropeptides tested were the molluscan FaRPs, FMRFamide and FLRFamide, the turbellarian FaRPs, RYIRFamide and GYIRFamide, the cestode peptides, NPF and GNFFRFamide, and the nematode FaRPs, AF-1 (KNEFIRFamide), AF-2 (KHEYLRFamide), AF-8 (KSAYMRFamide), and PF-4 (KPNFIRFamide). Dose-response experiments were undertaken at a concentration range of 5 nM–5 μM for all of the neuropeptides tested. FMRFamide and AF-8 caused statistically significant increases in the amplitude and frequency of contractions at concentrations of 0·5 μM and 5 μM. FLRFamide and AF-2 also caused significant increases in contraction frequency at concentrations of 0·5 μM and 5 μM, although a significant increase in amplitude of contraction was observed only at a concentration of 5 μM. GYIRFamide increased both amplitude and frequency significantly at concentrations of 50 nM, 0·5 μM and 5 μM. RYIRFamide significantly increased frequency of contractions at concentrations of 0·5 μM and 5 μM, but failed to have a significant effect on contraction amplitude. AF-1 at a concentration of 5 μM increased contraction amplitude, but failed to have an effect on frequency at any of the concentrations used. PF-4 caused a statistically significant increase in both the amplitude and frequency of contractions at a concentration of 5 μM. NPF and GNFFRFamide had no effect on the in vitro motility of F. hepatica over the range of concentrations tested. The results are discussed in the light of possible structure–activity relationships in the FaRPs tested.