The identity of Hyalomma lusitanicum K. and H. anatolicum K. is discussed. The male and female of the two species are described. H. anatolicum is considered as species inquirenda, but distinct from H. anatolicum anatolicum (sensu Pomeranzev) and H. anatolicum excavatum (sensu Pomeranzev). H. anatolicum anatolicum and H. anatolicum excavatum are considered to be one polymorphic species. This species should be called H. excavatum as it tallies with the still existing type specimen of H. excavatum Koch; it should not be called H. anatolicum as it does not correspond to Koch's description of H. anatolicum. The name H. anatolicum should for the present be reserved for a species resembling H. excavatum, but characterized by the light yellow colour of the anterior part of the scutum. It remains to be determined by breeding experiments whether this character is constant.

The host–parasite relationships of several notoedrid and teinocoptid mites of two Malaysian bats, Cheiromeles torquatus (the hairless bat) and Cynopterus brachyotis (the common fruit bat), were studied.

C. torquatus is parasitized by five species of Notoedres (family Sarcoptidae)—N. alexfaini, N. longisetosus, N. elongatus, N. rajamanickami and N. cheiromeles. Two, N. alexfaini and N. longisetosus, are responsible for generalized mange, which affects mainly the trunk. The three remaining species produce small, discrete lesions, each having a distinctive morphology and polarity.

Notoedres elongatus causes papilliform swellings, usually over the bony parts of the wing. It inhabits deep burrows in the swellings, which consist largely of hyper-plastic connective tissue heavily infiltrated with round cells. The lesions produced by N. rajamanickami resemble those of N. elongatus, except that they are located on the head in the neighbourhood of the vibrissae and are not elevated. N. cheiromeles dwells in cupules in the stratum corneum on various parts of the body, including the wings. These cupules are formed as a result of an intense hyper-keratosis in the immediate vicinity of the mites.

The reaction of the skin of Cynopterus brachyotis to the teinocoptid mite, Teino-coptes asiaticus (family Teinocoptidae), expresses itself chiefly as an extensive acanthosis. There is little or no thickening of the stratum corneum except on the lips of the epidermal cupule in which the anterior end of the mite rests. The dermis underlying the mite undergoes moderate fibroblastic proliferation.

We would like to thank Mr Lim Boo Liat of the Institute for Medical Research, Kuala Lumpur, and Mr Eric Alfred of the National Museum, Singapore, who very kindly allowed us to examine material from their collections. Mr Lim also assisted in other ways and proved to be a genial and helpful host when we visited his laboratory at the IMR. We are also most grateful to Professor John Harrison, who so generously provided us with space in his department.

This paper demonstrates that the establishment and growth of the filarial nematode parasite, Litomosoides carinii, is reduced in pyridoxine-deficient cotton rats. Young cotton rats were assigned to one of three dietary groups: vitamin B6-deficient cotton rats (B6 –AL) were fed a pyridoxine-free diet ad libitum; pair-fed controls (B6 + PF) were fed the same amount of pyridoxine-free diet as animals in the deficient group and given daily oral supplements of 100 μg pyridoxine; and pyridoxine-sufficient controls (B6 + AL) were fed the pyridoxine-free diet ad libitum and supplemented daily with 100 μg pyridoxine. Half of each group was infected with 50 L3 of L. carinii by subcutaneous injection 8 weeks after the start of the experimental feeding period. B6-deficient cotton rats ate less (P < 0·001) and gained less weight (P < 0·001) than B6-supplemented controls. The levels of microfilaraemia in deficient animals, measured weekly throughout the experiment by taking blood smears, was significantly lower than in supplemented animals (P < 0·001). The deficient rats became latent for L. carinii at 20 weeks post-infection, whereas there was patent microfilaraemia in rats in the other dietary groups until the end of the experiment. Smaller (P < 0·001) and fewer (P < 0·05) adult worms were recovered from the pleural and abdominal cavities of deficient animals than from either pair-fed or sufficient controls at autopsy 28 weeks post-infection.

Research and innovation in the diagnosis of infectious and parasitic diseases has led to the development of several promising diagnostic tools, for example in malaria there is extensive literature concerning the use of rapid diagnostic tests. This means policymakers in many low and middle income countries need to make difficult decisions about which of the recommended tools and approaches to implement and scale-up. The test characteristics (e.g. sensitivity and specificity) of the tools alone are not a sufficient basis on which to make these decisions as policymakers need to also consider the best combination of tools, whether the new tools should complement or replace existing diagnostics and who should be tested. Diagnostic strategies need dovetailing to different epidemiology and structural resource constraints (e.g. existing diagnostic pathways, human resources and laboratory capacity). We propose operational modelling to assist with these complex decisions. Projections of patient, health system and cost impacts are essential and operational modelling of the relevant elements of the health system could provide these projections and support rational decisions. We demonstrate how the technique of operational modelling applied in the developing world to support decisions on diagnostics for tuberculosis, could in a parallel way, provide useful insights to support implementation of appropriate diagnostic innovations for parasitic diseases.

Plant cysteine proteinases (CPs) from Carica papaya kill parasitic and free-living nematodes in vitro by hydrolysis of the worm cuticle, a mechanism that is different to all commercially available synthetic anthelmintics. We have developed a cheap and effective, rapid-throughput Caenorhabditis elegans-based assay for screening plant CP extracts for anthelmintic activity targeting cuticular integrity. The assay exploits colorimetric methodology for assessment of cuticular damage, and is based on the ability of viable cells to incorporate and bind Neutral red dye within lysosomes and to release the dye when damaged. Living worms are pre-stained with the dye, exposed to CPs and then leakage of the dye through the damaged cuticle is quantified by spectrophotometry. In contrast to motility assays and semi-subjective interpretation of microscopical images, this colorimetric assay is independent of observer bias. Our assay was applied to a series of C. elegans bus mutant strains with leaky cuticles and to cystatin knockout mutants. At ambient temperature and over 0.5–24 h, both bus mutants and the cystatin knockouts were highly susceptible to CPs, whereas wild-type Bristol N2 worms were essentially unstained by Neutral red and unaffected by CPs, providing validation for the utility of this assay.

A strain of Plasmodium gallinaceum has been treated for 10 weeks with sulphadiazine (5 mg./20 g.) in the presence of p-aminobenzoic acid in doses (0·5 mg./ 20 g.) inhibiting the sulphadiazine. No resistance to paludrine or to sulphadiazine has developed.

Different lineages experience different rates of phenotypic diversification, resulting in greater or lower variance in the expression of phenotypic traits among the species within a lineage. Here, morphological diversification is investigated in 14 different trematode families, based on a dataset comprising morphometric data on body size and 4 anatomical structures (oral sucker, ventral sucker, pharynx, cirrus sac) from 386 species. Three hypotheses are tested and subsequently rejected based on the empirical evidence. First, the degree of morphological variation in all traits within a trematode family, measured as the coefficient of variation among species, appears independent of the average body size of species belonging to that family. Second, patterns of morphological diversification appear similar whether endothermic or ectothermic vertebrates are used as definitive hosts. Third, phylogenetically older trematode lineages did not display greater morphological variation than younger, more derived ones, ruling out evolutionary time as an explanation. The results are consistent with developmental constraints acting on morphological diversification, since for some pairs of traits, variation in one trait is not independent of variation in another trait. More importantly, across most families, variation in body size was significantly more pronounced than variation in the relative sizes of the other morphological features. Trematode body size therefore varies widely while the general body architecture of the family is maintained. The fact that the evolution of the body plan is more conservative than that of body size suggests that the range of morphologies that can evolve in trematodes is constrained.

The route of migration of Cercaria X within the host snail, Lymnaea stagnalis, has been demonstrated by means of serial sections and a method of numerical assessment of the distribution of cercariae in the various tissues and organs of the body.

The main pathway along which migrating cercariae travel is the blood system, which differs from the route in the fish second intermediate host. The cercariae enter the main visceral haemocoel by rupture of the wall of the digestive gland and from there enter the main venous vessels deploying through the rectal sinus, sub-renal sinus, lung and heart. The cercariae travel from the heart via the mantle arteries to localize in the mantle sinuses prior to emergence.

The inner surface of the mantle, and in particular its leading edge, is the main site of emergence, and escape of cercariae is, in the final stages at least, an active process. It is suggested that passage of parasites in the blood stream is partly active.

Migration and subsequent emergence is probably facilitated by the activity of the oral cap of spines, the general activity of the cercaria and the activity of the oral and ventral suckers.

A tissue response to the presence of cercariae in the blood vessels and tissues of the mantle is evident, the cells responsible for this being, possibly, actively phagocytizing amoebocytes of the mollusc's blood. The swellings in the epidermis of the mantle in heavy infections may be the result of an accumulation of these cells.

Grateful acknowledgement is expressed to Professor J. Brough for the facilities and encouragement provided during the course of this study. This work was carried out during the tenure by A. J. Probert of a D.S.I.R. Research studentship.

I wish to thank the Society for inviting me to give the Introductory Talk in this Symposium. It is going to centre around what might be called ‘epitope specific’ immunization and I want to draw your attention to a number of factors which will be bound to affect any new approach to the development of vaccines. To begin with, it is now clear that complex antigens, such as those associated with parasites, present many different epitopes to the immune system. These epitopes are ‘seen’ by different cell types using different receptors and epitope recognition can activate a number of different effector systems.

The course of a primary Necator americanus infection was studied in the lungs and small intestines of syngeneic mice. Following percutaneous infection no difference in initial larval establishment in the lungs was found between male BALB/c, NIH or B10.G mice. However, significant differences in the subsequent kinetics of infection were demonstrated between the BALB/c and NIH strains. Lung worm burdens declined more slowly in NIH mice than in BALB/c strain. Surprisingly, however, a greater proportion of larvae remaining in the lungs of BALB/c mice, 9 days p.i., were trapped than in NIH mice. Nevertheless, establishment in the small intestines of the BALB/c strain was consistently greater than in NIH mice. Host immunosuppression resulted in increased larval retention in the lungs of both the BALB/c and NIH strains as well as in the small intestines of BALB/c mice. Treatment with hydrocortisone acetate did not increase intestinal worm burdens in NIH mice. The data presented suggest that, in this complex, dynamic model system, designation of ‘susceptible’ and ‘resistant’ strains is inappropriate. The factors underlying the observed strain differences in resistance to infection are discussed.

A distinct 8 kDa calcium-binding protein (CaBP) is preferentially expressed at the cercarial stage during the life-cycle of the schistosome. Available data indicate that this CaBP may be associated with tissue/organ remodelling (involving protein degradation and synthesis of new proteins) during transformation of the cercariae from free-living form in water to parasitic life in the vertebrate host. Many CaBP molecules (e.g. calmodulin) show Ca++-dependent interaction with target proteins and thus modulate their activity. Accordingly, the parasite 8 kDa CaBP was used as a probe to clone and identify putative target protein(s) directly by binding interaction. Screening of schistosome λgt11 expression library with radio-iodinated CaBP yielded several overlapping clones showing Ca++-dependent binding of the CaBP. Sequence analyses revealed that these clones encode the S5a/Rpn10 multiubiquitin-binding protein which is a component of the regulatory 19S subunit of the 26S proteasome. The schistosome molecule, designated SmS5a, is 420 amino acids long. The nearly full length molecule (Gln3–Ser420) as well as the amino terminal (N-S5a, Gln3–Gly200) and carboxyl-terminal (C-S5a, Asp225–Ser420) portions were synthesized in bacteria, purified, and antibodies to the parasite SmS5a were prepared. Interaction between SmS5a and the 8 kDa CaBP in a Ca++-dependent manner was found under various experimental conditions: CaBP-Sepharose bound soluble SmS5a, immobilized SmS5a bound soluble CaBP, and complex formation was found when both molecules were in solution. Furthermore, it was shown that the C-terminal portion of SmS5a, but not the N-terminal portion of the molecule, reacted with the CaBP. SmS5a synthesized in a cell-free system and Western blots revealed 2 species, conceivably corresponding to the naked molecule (~50 kDa) and the molecule subjected to post-translational modification (~70 kDa). The present studies suggest that proteasome activity may be modulated by calcium, and this modulation is mediated via CaBP molecule(s).

The role of Mycobacterium w (Mw) vaccine as an immunomodulator and immunoprophylactant in the treatment of mycobacterial diseases (leprosy and pulmonary tuberculosis) is well established. The fact that it shares common antigens with leishmanial parasites prompted its assessment as an immunostimulant and as an adjunct to known anti-leishmanials that may help in stimulating the suppressed immune status of Leishmania donovani-infected individuals. The efficacy of Mw vaccine was assessed as an immunomodulator, prophylactically either alone or in combination with anti-leishmanial vaccine, as well as therapeutically as an adjunct to anti-leishmanial treatment in L. donovani-infected hamsters, representing a chronic human Visceral Leishmaniasis (VL) model. Similarly, its efficacy was also evaluated in L. donovani-infected BALB/c mice, representing an acute VL model. The preliminary studies revealed that Mw was ineffective as an immunostimulant and/or immunoprophylactant in hamsters infected with L. donovani, as estimated by T-cell immunological responses. However, in the BALB/c mice-VL model it appeared as an effective immunostimulant but a futile prophylactic agent. It is therefore inferred that, contrary to its role in managing tuberculosis and leprosy infections, Mw vaccine has not been successful in controlling VL infection, emphasizing the need to find detailed explanations for the failure of this vaccine against the disease.

A morphological and histochemical study has been made of atresia in oocytes in the ovarian balls of an acanthocephalan (Centrorhynchus corvi). Growing oocytes and mature oocytes have been observed to undergo atresia. With the start of atresia, the nuclear and cytoplasmic components are observed to be greatly altered. The atretic oocytes develop abnormal aggregations of cell components, which contain proteins, phospholipids and lipoproteins. It is suggested that the cellular products of degenerating oocytes are gradually absorbed by the supporting syncytium. The atresia of growing oocytes is greater in uninseminated than in inseminated females, which indicates that in the absence of a mating stimulus atresia occurs more frequently.

On 28. viii. 1932 seven specimens of Graffilla gemelipara Linton 1910 were found by Miriam Rothschild on the body inside the mantle cavity of a specimen of Cardium edule from Millbrook, Plymouth.

Though only taken previously in America and on a different host, Modiolus plicatulus, Linton's excellent figure leaves no doubt that these specimens belong to the same species.

Infection in mice (BALB/cABom) with the intestinal trematode Echinostoma caproni had a negative influence on pregnancy. The effect of the infection set in immediately following implantation (day 5 of pregnancy) resulting in fewer foetuses being present in infected mice on day 9 than in the controls. Ovulation, fertilization of eggs, and implantation itself were obviously not impaired. The infected mice had significantly lower serum progesterone levels on day 5 of pregnancy than the non-infected controls. It is speculated that the progesterone levels in the infected female mice were too low to secure early post-implantation gestation.

Chagas disease (CD) is a neglected disease and endemic in Brazil. In the Brazilian Northeast Region, it affects millions of people. Therefore, it is necessary to identify the spatiotemporal trends of CD mortality in the Northeast of Brazil. This ecological study was designed, in which the unit of analysis was the municipality of the Brazilian northeast. The data source was the Information System of Mortality. It was calculated relative risk from socioeconomic characteristics. Mortality rates were smoothed by the Local Empirical Bayes method. Spatial dependency was analysed by the Global and Local Moran Index. Scan spatial statistics were also used. A total of 11 287 deaths by CD were notified in the study. An expressive parcel of this number was observed among 70-year-olds or more (n = 4381; 38.8%), no schooling (n = 4381; 38.8%), mixed-race (n = 4381; 62.3%), male (n = 6875; 60.9%). It was observed positive spatial autocorrelation, mostly in municipalities of the state of Bahia, Piauí (with high-high clusters), and Maranhão (with low-low clusters). The spatial scan statistics has presented a risk of mortality in 24 purely spatial clusters (P < 0.05). The study has identified the spatial pattern of CD mortality mostly in Bahia and Piauí, highlighting priority areas in planning and control strategies of the health services.

Huff & Gambrell (1934), and Gambrell (1937) observed that, when Plasmodium cathemerium was passaged from canary to canary for a long period, by inoculation of blood from acutely infected birds, the number of gametocytes produced in each infection gradually decreased, though in two strains only did they disappear completely.

The present paper deals mainly with some new species of cestodes collected from birds commonly occurring in and near Nagpur, C.P., India.