Regional differences of Hymenolepis diminuta to immune lysis have been investigated by monitoring surface membrane fluidity utilizing fluorescence recovery after photobleaching (FRAP). Although the surface membrane of the newly excysted stage was completely immobile the molecular fluidity of the strobila membrane of 4-day-old parasites was greater than that associated with the scolex/neck region. Significant differences (P>0·001) occurred in the mobility of the strobila membrane of 4-day-old H. diminuta from 100-worm infections compared with 7- and 21-day-old parasites and 4-day-old individuals from 10-worm infections. Exposure to 50% normal rat serum and 1 mg/ml rat C reactive protein decreased or eliminated membrane fluidity. The significance of membrane mobility is discussed with reference to resistance to complement-mediated lysis and destrobilation.

Although eosinophilic bar- or droplet-like inclusions are frequently detectable inside eggs deposited in the livers of Schistosoma japonicum-infected animals, little is known of their exact nature. In the livers of mice implanted with freshly laid eggs, inclusion-positive eggs were found in 28·7 and 46·2% of deposited eggs at 2 and 4 weeks, respectively, after implantation, but in 4·3% at 5 weeks when most of the eggs had already degenerated. When the extent of granuloma formation was investigated, granulomas around inclusion-positive eggs were smaller than those around negative eggs. Host factors associated with the formation of inclusion were sought using in vivo and in vitro studies. Following the administration of anti-egg antigen serum into egg-implanted mice, no increase in occurrence of inclusion-positive eggs was seen. In a co-culture of mature eggs with infected rabbit or mouse serum, inclusions were rarely found. In contrast, they were found in 17·9% of eggs in the presence of splenic cells. The present study is the first to show that there is decreased granuloma formation in the presence of eosinophilic inclusions inside eggs and our in vitro study suggests that host cell–egg interaction is responsible for the formation of inclusions.

Localization of the type 2 Alu sequence (B2), a highly repetitive DNA sequence in the mouse genome, was examined by in situ polymerase chain reaction (in situ PCR) in schistosomes. The signals to the B2 sequence were detected in the cytoplasm of the tegumental membrane and in the nuclei of the mesenchymal, testicular, ovarian and vitelline cells of 8- week Schistosoma japonicum. In contrast, it was difficult to detect any signals of this sequence in 8-week S. mansoni, whereas in 24-week male S. mansoni the signals were observed in the cytoplasm of the tegumental tubercles and in the nuclei of the mesenchymal and testicular cells. On the other hand, in 24-week female S. mansoni the signals were found in the nuclei of the mesenchymal, ovarian and vitelline cells but not found in the tegument. On the contrary, no hybridization band of the B2 sequence was detected in the amplified DNA of 3-week schistosomula of either species. These observations proved that the host DNA sequences existed in restricted schistosome cells and were accumulated in the schistosome body during their development.

Habitat disturbance often results in alterations in community structure of small mammals. Additionally, the parasites harboured by these small mammals may be impacted by environmental changes or indirectly affected by changes in available hosts. To improve our understanding of this interplay, we examined the patterns of parasitism in small mammal communities from a variety of habitats in forested Uganda. Small mammals were collected from areas experiencing variable habitat disturbance, host density and species richness. The analysis focused on 3 most abundant rodent species, Lophuromys aquilus, Praomys jacksoni and Hylomyscus stella, and a diverse group of parasites they harbour. The impact of various habitat and host community factors on parasite prevalence was examined using linear regression and Spearman's rank-order correlation. We further investigated the parasite communities associated with each individual using correspondence analysis. We determined that, parasite prevalence and richness may be occasionally influenced by community and habitat factors, but taxonomy is a driving force in influencing the parasite community harboured by an individual host. Ultimately, applying general principles across a broad range of disturbance levels and diverse host communities needs to be approached with caution in complex communities.

This is the first report on the development and characterization of eight monoclonal antibodies (MABs) generated against whole- and membrane-enriched tachyzoite extracts of the apicomplexan parasite Besnoitia besnoiti. Confocal laser scanning immunofluorescence microscopy was used to localize respective epitopes in B. besnoiti tachyzoites along the lytic cycle. A pattern compatible with dense granule staining was observed with MABs 2.A.12, 2.F.3 and 2.G.4, which could be confirmed by immunogold electron microscopy for MABs 2.A.12 and 2.F.3. In particular, MABs 2.F.3 and 2.G.4 were secreted during early invasion, proliferation and egress phases. MABs 3.10.8 and 5.5.11 labelled the tachyzoite surface, whilst MABs 1.17.8, 8.9.2 and 2.G.A recognized the apical tip, which is reminiscent for microneme localization. Besides, the epitopes recognized by the latter two (MABs 8.9.2 and 2.G.A) exhibited a redistribution from the anterior part across the parasite surface towards the posterior end during invasion. Most MABs developed were genus-specific. Indeed, the MABs cross-reacted neither with T. gondii nor with N. caninum tachyzoites. In summary, we have generated MABs that will be useful to study the key processes in the lytic cycle of the parasite and with additional promising diagnostic value. However, the molecular identity of the antigens recognized remains to be elucidated.

Trombicula tamiyai and T. fujigmo n.sp. are described and figured from Japan and northern Burma respectively; the holotypes are in the U.S. National Museum. The first, unnamed or referred to European autumnalis, has previously been illustrated and discussed by some Japanese authors with T. japonica Tanaka et al., under the term Japanese harvest mites (‘akidani’). Figures of T. japonica are also provided here for comparison. Reared nymphs and adults are reported by the Japanese as unusually elongate for trombiculid mites. Figures of the elongate nymphs are comparable with that given by Hirst for T. autumnalis, the European harvest mite, the adult of which is likewise elongate. Should further data, including rearing, indicate the need for generic separation of this group of ‘harvest mites’ from Trombicula, then Neotrombicula Hirst would apply. Specific characters for other apparently related species are tabulated and discussed.

Habitat and Record. The animal under consideration, a parasitic member of the Copepoda, and belonging to the family Lernaeopodidae, occurs commonly on the males, and much less frequently on the females, of Scyllium canicula. The point of fixation is just outside the cloaca, between the pelvic fins, the parasite remaining attached permanently by the second maxillae to the tissues of the host, and occasionally even to the claspers, on their sides, preferably in the groove. I have several times found as many as six specimens on one host (Fig. 1), while three or four is a usual number.

1. NR bodies show special affinity for neutral red. They are rounded or irregular in outline, measuring 0·25–12·5µ in diameter.

2. In fixed preparations NR bodies appear as spherical and vacuolated structures.

3. RNA is present in abundance in mature NR bodies, but while DNA is present in variable amount, the Feulgen technique shows that in their very young stage NR bodies are rich in DNA.

4. Glycogen is absent from the NR bodies, but Hale's technique provides evidence that the hyaluronic acid type of polysaccharide is present in them.

5. By Gomori's modified technique the presence of alkaline phosphatase in the NR body was demonstrated.

6. The mature NR bodies multiply by a process of budding. Small buds or spherules rich in DNA infect fresh spermatogonial cells, the latter being converted into the ‘pathological cells’ of Hertig.

The karyotype of Transversotrema patia1en consists of 10 pairs of chromosomes (2n = 20) of which 5 pairs are metacentrics and 5 pairs are submetacentrics. The chromosomes are large and range in size from 5 to 12 μm. The total chromosome length of the diploid complement is 16783 μm. Stages of spermatogenesis including the two gonial divisions and two reduction divisions leading to production of spermatozoa occur in cercarial embryos inside snail tissue, while the maturation divisions of the ovum occur in eggs freshly liberated by the fluke. The chiasma frequency is high, being 3888/cell and 388/bivalent. Cytological data indicate an independent phylogenetic status for the family Transversotrematidae.

A new species of cephaline gregarine, Gregarina rhyparobiae n.sp., parasitic in the gut of a tropical cockroach Rhyparobiae maderae, from East Africa, is described.

In a previous paper which appeared in Parasitology, Vol. III. pp. 73–07, and the Journal of Tropical Veterinary Science, Vol. n. No. I, details were given of thirty-two cases of successful treatment of Surra in horses by means of arsenic and its derivatives.

The uptake of glucose by Acanthocheilonema viteae was studied in vitro. The process was selective for the D-isomer and saturatable with a Km of 2 mM. The rate of glucose transport/utilization was inhibited by 2-deoxyglucose, mannose, 5-thioglucose and dipyridamole but, unlike mammalian systems, was not impaired by cytochalasin B, phloretin, phloridzin, 3-O-methylglucose and 4, 6-ethylideneglucose. A potential chemotherapeutic advantage of selectively inhibiting filarial glucose transport exists for the following reasons. (1) The glucose transporter present in A. viteae was shown to be different from the one present in some mammalian systems. (2) Incubation under glucose-free conditions led to glycogen depletion, loss of motility and worm death. (3) Worms maintained in vitro for more than 18 h without glucose did not survive when implanted into gerbils.

The main theme of this series of papers will be the power of the three wellknown members of the brucei group of trypanosomes, T. brucei, T. rhodesiense and T. gambiense, to infect man. Inextricably involved with this problem are two others, both of practical importance: (1) Can the African big game serve as a reservoir for human trypanosomiasis? and (2) What are the affinities existing among these three trypanosomes? This may appear to be an inversion of the real order of importance, but a study of the literature on the brucei group, past and recent, reveals that infectivity to man dominates all other considerations.

Mycetosporidium jacksonae n.sp. occurs as a parasite in the intestinal epithelium and the malpighian tubules of weevils of the genus Sitona. The life history comprises vacuolated and compact plasmodia in which arise ovoid or spherical multinucleate bodies resembling coccidian schizonts. Sporulation results in the formation, within thin-walled sporangia, of 8-nucleate, biconvex spores with densely staining, resistant walls. Other types of multiplication occur in the form of small uninucleate, fusiform bodies developed directly from the plasmodia; and of small uninucleate, ovoid or fusiform bodies, four to six of which are formed within each chamber of a multilocular sporangium.

The parasite resembles M. talpa Léger & Hesse 1905, but differs in some characters and, consequently, the new species M. jacksonae is made for it.

The genus Mycetosporidium is of uncertain systematic position and appears to be related to the Mycetozoa, but it also resembles the Haplosporidia in some characters.

(The slides upon which the description of M. jacksonae is based are deposited in the Molteno Institute of Biology and Parasitology, University of Cambridge.)

The writer (Sprent, 1971) described four female specimens of an ‘ascaridoid’ nematode from a vial labelled ‘Tasmanian Marsupial Wolf’. The name Cotylascaris thylacini was proposed, in spite of there being no male specimens available. This was because no other genus among ascaridoids was known by the writer to possess cup-like cuticular structures on the margins of the lips and also because the thylacine (Thylacinus cynocephalus) is considered to be on the verge of extinction, if not extinct already.

In natural grazing grounds, bovines affected with East Coast fever remain ambulatory until a few days or even a few hours before death, and larval and nymphal Rhipicephalus appendwulatus and R. evertsi, which have fed and engorged, will infest the pasture over a wide area. Subsequently, when susceptible cattle graze over this area small numbers of infected instars may attach at intervals and begin to feed. In this experiment an attempt was made to simulate these conditions as closely as possible.

In group A wnere one infected tick was fed on the 1st day, two on the 3rd day, and three on the 21st day, two out of six calves developed an unmistakable East Coast fever infection, with Koch's bodies present in gland smears. In one calf (no. 5724) the reaction was most severe and was undoubtedly due to the three ticks which attached on the 1st and 3rd days, while in another calf (no. 115) the reaction was less severe and was most probably due to the three ticks which attached on the 21st day.

In group B where one infected tick was fed on the 1st day, two on the 5th day, and three on the 21st day; five out of six calves gave a definite unmistakable East Coast fever reaction with Koch's bodies present in gland smears, four of the reactions being undoubtedly due to the three ticks which attached on the 1st and 5th days. There is as yet no reasonable explanation as to why the number of definite reactors should differ so markedly in the two groups.

It is noteworthy that all these reactions were mild and that recovery in each case was uneventful. The only death to occur was control calf no 5729, on which ten infected ticks had fed at one time, but from the results of the other controls it may be assumed that the strain of Theileria parva had by some means become attenuated or that the calves had increased tolerance or resistance.

It is difficult to understand why calf no. 109 failed to react in the first experiment but showed some susceptibility when challenged 96 days later, and why calves nos. 5711, 116, 5642 and 39 gave doubtful reactions. No explanation can be given at this stage, but it raises two practical questions. First, it is difficult to assess the minimum intensity of a reaction which is sufficient to give a durable immunity. The fact that calf no. 114, after what appeared to be a definite T. parva reaction, reacted a second time on exposure to infection 110 days later, proved that the immunity was not prolonged. It is true that the first reaction was only mild, but practically the same remarks could be applied to calves nos. 117 and 5725, yet these calves had not lost their immunity on challenge. Secondly, it is difficult to ensure, by observation of daily temperatures alone, that all calves are really fully susceptible before being used on a critical East Coast fever experiment, for if only a few infected ticks are accidentally introduced into stables or grazing paddocks, it may be assumed that mild subclinical infections will result. These calves may then show varying degrees of resistance to subsequent infections, and results such as those experienced in these experiments would be a normal sequelae.

The intensity of the leucopaenia appeared to bear no relationship to the number of days Koch's bodies were present in gland smears. It was present before the first rise in temperature in all the calves except no. 114, the only calf to show a second reaction on challenge.

This paper reviews current knowledge of the structure, genesis, cytochemistry and putative functions of the haplosporosomes of haplosporidians (Urosporidium, Haplosporidium, Bonamia, Minchinia) and paramyxids (Paramyxa, Paramyxoides, Marteilia, Marteilioides, Paramarteilia), and the sporoplasmosomes of myxozoans (Myxozoa – Malacosporea, Myxosporea). In all 3 groups, these bodies occur in plasmodial trophic stages, disappear at the onset of sporogony, and reappear in the spore. Some haplosporidian haplosporosomes lack the internal membrane regarded as characteristic of these bodies and that phylum. Haplosporidian haplosporogenesis is through the Golgi (spherulosome in the spore), either to form haplosporosomes at the trans-Golgi network, or for the Golgi to produce formative bodies from which membranous vesicles bud, thus acquiring the external membrane. The former method also forms sporoplasmosomes in malacosporeans, while the latter is the common method of haplosporogenesis in paramyxids. Sporoplasmogenesis in myxosporeans is largely unknown. The haplosporosomes of Haplosporidium nelsoni and sporoplasmosomes of malacosporeans are similar in arraying themselves beneath the plasmodial plasma membrane with their internal membranes pointing to the exterior, possibly to secrete their contents to lyse host cells or repel haemocytes. It is concluded that these bodies are probably multifunctional within and between groups, their internal membranes separating different functional compartments, and their origin may be from common ancestors in the Neoproterozoic.

The majority of Plasmodium falciparum field isolates are defined as complex infections because they contain multiple genetically distinct clones. Studying interactions between clones in complex infections in vivo and in vitro could elucidate important phenomena in malaria infection, transmission and treatment. Using quantitative PCR (qPCR) of the P. falciparum merozoite surface protein 1, block 2 (PfMSP1-B2), we provide a sensitive and efficient genotyping method. This is important for epidemiological studies because it makes it possible to study genotype-specific growth dynamics. We compared 3 PfMSP1-B2 genotyping methods by analysing 79 field isolates from the Peruvian Amazon. In vivo observations from other studies using these techniques led to the hypothesis that clones within complex infections interact. By co-culturing clones with different PfMSP1-B2 genotypes, and measuring parasitaemia using qPCR, we found that suppression of clonal expansion was a factor of the collective density of all clones present in a culture. PfMSP1-B2 qPCR enabled us to find in vitro evidence for parasite-parasite interactions and could facilitate future investigations of growth trends in naturally occurring complex infections.

Trypanosoma equiperdum possesses a dense coat of a variant surface glycoprotein (VSG) that is used to evade the host immune response by a process known as antigenic variation. Soluble and membrane forms of the predominant VSG from the Venezuelan T. equiperdum TeAp-N/D1 strain (sVSG and mVSG, respectively) were purified to homogeneity; and antibodies against sVSG and mVSG were raised, isolated, and employed to produce anti-idiotypic antibodies that structurally mimic the VSG surface. Prospective VSG-binding partners were initially detected by far-Western blots, and then by immunoblots using the generated anti-idiotypic antibodies. Polypeptides of ~80 and 55 kDa were isolated when anti-idiotypic antibodies–Sepharose affinity matrixes were used as baits. Mass spectrometry sequencing yielded hits with various proteins from Trypanosoma brucei such as heat-shock protein 70, tryparedoxin peroxidase, VSG variants, expression site associated gene product 6, and two hypothetical proteins. In addition, a possible interaction with a protein homologous to the glutamic acid/alanine-rich protein from Trypanosoma congolense was also found. These results indicate that the corresponding orthologous gene products are candidates for VSG-interacting proteins in T. equiperdum.