This study investigated the significance of serum complement on transmission-reducing activity (TRA) of field sera from 24 infected Plasmodium falciparum gametocyte carriers (from Cameroon) against cultured NF54 P. falciparum. Laboratory-reared Anopheles stephensi were given infectious blood meals prepared either with sera from naïve Dutch donor (AB type) or pair-matched field serum samples, both with and without active complement. TRA of serum factors and host complement on mosquito infection rate and oocyst intensity were divided into the various components involved in the early stages of sporogony. The majority (>80%) of sera tested showed positive antibody titres to Pfs230, the relevant complement-dependent target of transmission-reducing mechanisms. Regardless of the presence of active complement, bloodmeals with field sera exhibited significantly lower infection rates and oocyst intensity than the control group. Serological reactivity in Capture-ELISA against Pfs230 was significantly correlated with the reduction of parasite infectivity. Contrary to our expectation, the presence of active complement in the mosquito bloodmeal did not increase parasite losses and therefore the magnitude of transmission reduction by individual immune sera. Our findings on P. falciparum are consistent with previous studies on animal hosts of Plasmodium, indicating that early P. falciparum sporogonic stages may be insensitive to the antibody-dependent pathways of complement in human serum.

The resting membrane potential of the acanthocephalan rete system in Macracanthorhynchus hirudinaceus was −35±1·5 mV (n = 20) and was dependent upon the external potassium concentration. The membrane potential reached 0 mV when the external potassium concentration was 160 mM. Spontaneous spike potentials of 45 mV ± 10 were dependent on calcium flux. The membrane potential was depolarized by acetylcholine, potassium-free medium, calcium ions and chloride-free medium but not by changes in the external sodium concentration. Spontaneous potentials were increased in number by acetylcholine and calcium at concentrations above 3 mM, but were decreased in number by chloride- and calcium-free medium. Hence the rete system potentials are very similar to smooth muscle potentials in many respects.

The effects of a parasitic infection with the nematode Nippostrongylus brasiliensis on the degradation rates of cytoplasmic tRNA, rRNA and mRNA in rats have been investigated by measuring the renal excretion rates of the modified RNA catabolites N6-threoninocarbonyladenosine, pseudouridine and 7-methylguanine. Between days 9 and 13 post-infection when the expulsion of N. brasiliensis is usually the most pronounced, the degradation rates of the different RNA classes were significantly higher than in the control rats (P<0·05) by, on average, +24% (tRNA), +34% (rRNA) and +26% (mRNA). We suspect that the elevated degradation rates of RNA are related to an increased production of reactive oxygen species by the host during the expulsion of N. brasiliensis.

In the endemic countries, human cystic echinococcosis (CE) poses a serious medical and social problem. Because it most often affects the liver and lungs we aimed to define the proportion of cases with different organ localization, the diagnostic and therapeutic approaches in such cases, and the outcome of them. For a period 2010–2019, a total of 2863 cases of CE were registered in Bulgaria, of which 148 (5.17%) with organ localization other than liver and/or lung. The majority of patients with extra-hepatopulmonary localization of CE were adults. The distribution by gender showed predominance of female patients (57.43%) over those of males and primary cases (85.14%) exceeded the cases of recurrence. According to our study most common is the spleen involvement, followed by involvement of the abdominal cavity, kidneys and muscle/subcutaneous tissue. Other extra-hepatopulmonary organ localizations are significantly less common. This study shows that the extra-hepatopulmonary localization of CE is not so rare, and in most cases it is a primary disease. In respect of this, clinicians should consider hydatidosis in the differential diagnosis when cystic formation(s) is found, regardless of the organ involved.

We studied the compositional turnover in infracommunities and component communities of ecto- and endoparasites infesting a bat, Miniopterus natalensis (Chiroptera, Miniopteridae), across seven sampling sites using the zeta diversity metric (measuring similarity between multiple communities) and calculating zeta decline and retention rate (both scales) and zeta decay (component communities). We asked whether the patterns of zeta diversity differ between (a) infracommunities and component communities; (b) ecto- and endoparasites and (c) subsets of communities infecting male and female bats. The pattern of compositional turnover differed between infracommunities and component communities in endoparasites only. The shape of zeta decline for infracommunities indicated that there were approximately equal probabilities of ecto- and endoparasitic species to occur on/in any bat individual within a site. The shape of zeta decline for component communities suggested the stochasticity of ectoparasite turnover, whereas the turnover of endoparasites was driven by niche-based processes. Compositional turnover in component communities of ectoparasites was more spatially dependent than that of endoparasites. Spatial independence of compositional turnover in endoparasites was due to subcommunities harboured by female bats. We conclude that the patterns of compositional turnover in infracommunities were similar in ecto- and endoparasites, whereas the patterns of turnover in component communities differed between these groups.

The third-instar larval cuticles of Hypoderma bovis and H. diana and the puparial cuticle of H. bovis are described. The observations on and the descriptions of these cuticles are compared with the work of Enigk & Pfaff (1954) on H. bovis larval cuticle. The cuticles of the Hypoderma species are compared with the typical dipteran larval cuticle described by Dennell (1946) for Sarcophaga and found to approximate very closely to this basic pattern. In view of this it has been necessary to revise the terminology of the cuticular layers as originally described by Enigk & Pfaff for Hypoderma bovis. A description of the puparial cuticle and its specialized structure and the histological appearance of the pupal suture or line of weakness is given.

Among the ticks collected by Major E. W. Temple-Boreham from a giraffe at the Talek River, Cis-Mara area of W. Masai, Kenya, in October 1955, were eleven males and eight females which represent an undescribed species of the genus Rhipicephalus. Another female was collected by W. A. Hilton from a giraffe near mile 70 south of Arusha on the Great North Road, Tanganyika, on 10 July 1956, and G. H. Swynnerton collected three males from a giraffe at Nkonko, S. Manyoni district, Tanganyika, on 29 September 1958. The following is a description of these specimens.

In the blood of the above mammals there was found in varying proportions those enigmatical bodies recently described by Theiler as Protozoa under the name Anaplasma marginale, but more generally known as “marginal points” or “coccus-like bodiees.”

The new species of Amblyomma described in this paper was collected and forwarded to the author for identification by Mr J. H. Calaby, Wildlife Section, C.S.I.R.O. This is the fourth species of the genus to be recorded from Western Australia, the others being A. australiense Neumann, A. albolimbatum Neumann, and A. triguttatum Koch (Roberts, 1953).

We examined a host system (Peromyscus maniculatus) in which a single autosomal gene controls susceptibility or resistance to infection by the cestode parasite Hymenolepis citelli. Parasite deaths of both primary and secondary (challenge) infections were examined, using a probabilistic model, to see if deaths were random and uncorrelated within each genotype. Within susceptible hosts, post-patent survival of primary worms was not random and heterogeneity was due to among-host effects rather than parasite-age effects, suggesting a second genetic or immunological process. Secondary infections in susceptible hosts appear to be lost randomly, independent of primary infection age or burden. The loss rate is similar to that for primary worms. The lack of correlation or alteration in (susceptible) host response to primary and secondary infections suggests that the latter are eliminated by a process that differs from that acting on primary worms. In resistant hosts, parasite survival rates suggest that the immunological process elicited by the primary infection also acts to eliminate the secondary infection more rapidly. Suggestions are made for improving experimental methods when dealing with mixed genotype populations. Experiments should permit direct estimation of genotype frequency and of parasite death rates within each genotype. This separation of host type is particularly important when studying correlation of successive worm burdens since any host or treatment mixture (genotype, age, sex, size or infection dose) may induce correlations that could be mistakenly interpreted.

It is well known that the ectoparasitic Arthropods often produce in their host various skin reactions such as macules, wheals and haemorrhages, which in many cases are due to the salivary secretion of these ectoparasites. Nuttall and Strickland (1908) were the first to find an anticoagulin (called “Ixodin” by Sabbatani) in the salivary glands and alimentary canal of Argas persicus. Bruck (1919) found that the organs of Culex contained a haemolytic- and urticaria-producing substance called by him “Culicin.” His study was not, however, precise, because he ground up the entire bodies of the gnats, thereby mixing up secretions, excretions and fragments of organs, some of which would never enter a wound in the process of blood sucking. Moreover, the urticaria following mosquito bite was found by Schaudinn to be due to the yeast present in the oesophageal diverticula of mosquito. Klausner (1916) states that the secretions of the salivary glands in Cimex are soluble in water and alcohol, are haemolytic and produce urticaria; he found also that they do not contain formic acid and that immunity to their effects is not acquired. Nuttall (1918) dealing with the effects of salivary glands of Phthirus on human skin states that the bluish spots of the skin are especially marked after biting of adult lice, that they have nothing to do with the blue spots in the fat body of the lice and that they are probably derived from the exuded and altered blood of man.

As the infection progresses in lambs, the developing germ cells of male Nematodirus battus become filled with lysosome-like bodies, electron-dense granules and membrane-bound vesicles, and the organization and division of the gametic nucleus appears to be altered. The epithelial cells of the reproductive tract are also damaged and the secretory-type globules produced by the cells of the vas deferens are denatured. These changes are compared with ultrastructural changes observed in other species of nematode affected by the immune response of their hosts.

I feel greatly honoured to have been asked to speak to you about Alphonse Laveran. Professor Garnham wondered if I had met Laveran and what was the State of his relations with Professor Emile Brumpt my father. I have known many Pastorians: Emile Roux, Mesnil, Marchoux, Roubaud, Charles Nicolle, but unfortunately not Laveran.