From morphological, biological and experimental data it is concluded that the attempt to merge Necator suillus in the synonymy of N. americanus is utterly unjustified.

Host: Cebus fatuellus. Habitat: Stomach. Locality : South America. Two males and two females were collected from the stomach of a Brown Capucin. The two males are respectively 37 and 41 mm. long by 1.5 and 1.65 mm. thick; the two females are respectively 54 and 60 mm.long by 2.9 and 2.75 mm. thick in their posterior third.

The surface tegument of G. tigrinum generally resembles that described for other digeneans. It contains surface tubercles and is covered with a glycocalyx. In the anterior region the tegument bears spines while tubular-like canals and occasional deep invaginations are present on the anteroventral surface. Two types of secretory body are present in the tegumental syncytium and produced in separate tegumental cells. Mitochondria are present in the surface syncytium, suggesting active transport occurs across the tegument in non-hibernating frogs.

Twelve batches of the mollusc Cernuella (Cernuella) virgata (Mollusca: Helicidae) were deposited monthly directly on faeces containing first-stage larvae of Neostrongylus linearis, so that they were naturally infected. Every two weeks the molluscs were examined to study the larval development of N. linearis. No correlation was found between the number of first-stage larvae of N. linearis on the faeces and the number of total larvae and third-stage larvae which developed in the snails. However, a negative correlation was found between temperature and the days needed to reach the different larval stages. Thus, the molluscs harboured third-stage larvae from mid-spring to mid-autumn, the period of time which carries the greatest risk of infection for the definitive hosts.

Rana temporaria tadpoles which had been naturally infected by larvae of Polystoma integerrimum were kept in the laboratory under conditions precluding the continuous re-infection which occurs in nature. One tadpole was seen to have two larvae attached to the skin of the ventral surface of the body, which were moving towards the posterior end. The tadpole measured 7·9 mm. in body length and 20·8 mm. in total length, and its stage of development corresponded to stage 5 in the table of development and metamorphosis compiled by Rugh (1951); it was collected in mid-May and had been kept for twelve days under laboratory conditions. The tadpole was fixed and dissected: the bladder had not developed, and the gills showed no indication of atrophy; the alimentary canal was long and heavily coiled, and filled with food. In addition to the two larvae observed on the skin, one larva was found in the branchial chamber, two were in the cloacal tube, seven occupied the cloacal chamber and two had travelled up the right ureter to the kidney; the alimentary canal was free of larvae. All fourteen larvae were gyrodactyloids.

The effects of infection with plerocercoids of Spirometra mansonoides on tissue glycogen deposition of rats was determined. Hypophysectomized rats infected for two days had higher liver glycogen concentrations than controls and this effect was greatest after one week. Elevated liver glycogen associated with plerocercoid infection was observed in fed animals both at the beginning and at the end of the light period as well as after an overnight fast. Glycogen phosphorylase (1,4αD glucan: orthophosphate α glucosyltransferase EC 2.4.1.1.) was inhibited but glucose-6-phosphatase (EC 3.1.3.9) was unaffected in the livers of infected hypophysectomized rats. While this effect is similar to actions of both growth hormone and insulin, plerocercoid infection had no influence on glycogen of cardiac or skeletal muscle at any time. Plerocercoid infection had no effect on the glycogen concentration of any tissue of intact rats.

During a visit to Kakinada, Andhra Pradesh (India) in April, 1956, the writer examined thirty specimens of the frog Rana cyanophlyctis and found that every one of them was heavily infected with an interesting nematode in the rectum. Large numbers of males and females of this parasite were collected and fixed in 5% formalin containing 10% glycerine. Specimens thus fixed and preserved could easily be dissected for preparing mounts of reproductive organs for detailed study. Before being dissected the preserved worms were at first washed in tapwater and then placed in 70% glycerine alcohol which was allowed to evaporate until the worms were in almost pure glycerine.

1. The effect of relative humidity on the survival and development of Neoascaris vitulorum eggs to the infective stage is described.

2. Tables showing the percentages of eggs at different stages of development and dead eggs at weekly interval for two different sizes of faecal masses are constructed and the results discussed.

3. Detailed weather graphs showing daily rainfall, average daily relative humidity and evapotranspiration for Ibadan and Obudu during the rainy season of 1964 are constructed and the effect of the weather on survival of Neoascans vitulorum eggs in pasture at these places is discussed.

4. The minimum relative humidity for the survival and development of Neoascaris vitulorum eggs to the infective stage is found to be 80%. The period of survival of eggs in a dry atmosphere depends on the size of the faecal mass containing the eggs. The critical relative humidity for Neoascaris vitulorum eggs is compared with values for other ascarids of domestic animals.

The serotoninergic and peptidergic components of the nervous system of the cercaria of Sanguinicola inermis (Digenea: Sanguinicolidae) were examined using whole-mount immunocytochemistry and a plan of the nervous system has been described. Antibodies to serotonin (5-hydroxytryptamine, 5-HT) and the neuropeptides, FMRFamide, GFNSALMFamide (S1) and SGPYSFNSGLTFamide (S2) were used in the study. Immunoreactivity (IR) was demonstrated to all but the S2 antisera and showed a similar fundamental distribution. IR was found in paired cerebral ganglia located anteriorly within the body and connected by a cerebral commissure. From the ganglia paired ventral and dorsal longitudinal nerve cords extend anteriorly into the cephalic organ and into the body. There is no apparent connection with the tail. Several transverse commissures connect the longitudinal nerve cords throughout the body and several associated cell bodies have been located. A double-stranded dorsal and ventral longitudinal nerve cord extends the length of the tail and six cell bodies are associated with these cords, uniquely demonstrating either FMRFamide and S1, or 5-HT-like IR. Only 5-HT-like IR was found to extend into the posterior tail furcae and there appears to be a lack of any peripheral tegumental innervation. Double-labelling experiments suggest that the serotoninergic and peptidergic components of the cercarial nervous system are distinct.

A sandwich antibody ELISA was employed for the detection of circulating filarial antigen in patients with bancroftian filariasis. Wuchereria bancrofti recombinant antigen-derived polyclonal and monoclonal antibodies were successfully used as the revealing antibodies and their efficiency was compared. All the microfilariae (mf) positive (by finger prick and examination of 20 μl of blood under the microscope) individuals tested showed the presence of circulating antigen(s). Among the antigen positive endemic normals (mf negative by the finger prick method), 43% showed microfilariae by a sensitive parasitological method viz. membrane filtration of the night blood samples. A significant correlation was observed between the parasite antigen levels and the blood microfilaria counts among the mf carriers. This information on the parasite antigen levels could be an ideal monitor to indicate the degree of active infection and in the follow up of chemotherapy.

The pathology associated with the early migratory phase of infection by the sparganum larvae of Spirometra theileri (Baer, 1925) Opuni and Muller, 1974 (Pseudophyllidea: Diphyllobothriidae), has been investigated in TO strain mice and in rhesus monkeys (Macaca mulatto). All infected mice developed haemorrhagic skin lesions and oedema of the joints and often ascites and peritonitis 3–6 weeks after infection. There was a 25% mortality in mice given plerocercoids orally, 37.5% in those injected with procercoids intraperitoneally. From eight weeks after infection larvae in both mice and monkeys were at various stages of encapsulation. One monkey which died three weeks after oral infection with 100 procercoids had developed ascites, haemorrhagic lesions and an acute peritonitis; infarcts were observed in the liver, lungs and spleen.

Protogynous cestodes are mostly parasites of charadriiform birds and have been reported from different regions of the world. In India Progynotaenia odhneri Nybelin, 1914 has been reported by two authors (Singh, 1952 and Singh, 1959) in the form of two separate and new species (see Discussion). The present communication is based upon a study of about two dozen specimens from an unidentified host shot in the vicinity of Bareilly, U.P. The present material, which was found to represent a new species of Progynotaenia Fuhrmann, 1909, possesses a remarkable feature in the disposition of the rostellar armature which is quite unlike that in any protogynous form so far described.

In vitro pairing studies on rediae of Echinostoma trivolvis, E. caproni, Zygocotyle lunata, Ribeiroia sp. and sporocysts from a species of armatae cercaria were undertaken at 22°C in a Petri dish bioassay containing an agar substratum and a Locke's 1:1 overlay. Pairing was arbitrarily defined as larvae in contact or within 1 mm of each other. Intraspecific and interspecific pairing occurred in the bioassay using several larval combinations initially placed 5 or 10 mm apart. Intraspecific pairing occurred with the rediae of Ribeiroia sp. and interspecific pairing was seen between E. trivolvis or E. caproni and Ribeiroia sp. A previous study documented intraspecific and interspecific pairing between rediae of E. trivolvis and E. caproni. Armatae sporocysts did not pair intraspecifically or interspecifically when matched with either E. caproni or E. trivolvis rediae. Intraspecific pairing of Z. lunata or interspecific pairing between Z. lunata rediae and echinostome rediae did not occur. The significance of redial pairing remains unclear.

The Bordet-Gengou test applied to the diagnosis of cases of suspected hydatid infection has been used by many workers since first introduced by Ghedini in 1906, using as antigen hydatid fluid from human cysts.

By means of scanning electron microscopy, aspects of the attachment of Moniliformis dubius (Acanthocephala) to the intestinal wall of the rat are described together with various changes in the structure and form of the mucosa. Attachment of the parasite results in the formation of a distinct pit around the everted proboscis and a crater around the neck. Contact between the anterior region of the trunk of the worm and the intestine of the host appears to lead to villous fusion so that characteristic grooves are formed in the mucosal tissue. Evidence was also obtained to suggest that host goblet cells may become exhausted during the course of an infection with Moniliformis.

The isoenzymes of acid and alkaline phosphatases and their histochemical localization were studied by polyacrylamide disc gel electrophoresis in four species of trematodes: Gigantocotyle explanatum from the liver and Gastrothylax crumenifer from the rumen of water buffalo (Bubalus bubalis) and Echinostoma malayanum and Fasciolopsis buski from the small intestine of the pig (Sus scrofa). Both acid and alkaline phosphatases were present in the tegument, gastrodermis, suckers, testes, ovary, eggs, vitellaria and uterus but alkaline phosphatase activity was demonstrated only in the parenchyma and excretory ducts. Polyacrylamide gel electrophoresis revealed two to four isoenzymes for both acid and alkaline phosphatase.

Recently (1924) Chandler has described from the duodenum of a Bennett's Wallaby (Macropus bennetti), a new genus of Trichostrongylidæ. Shortly after the publication of this paper, the writer was privileged to study what appears to be a second new species from the same host. The parasites are very small forms and occur mainly in the stomach, but are also found occasionally in the first part of the small intestine. A few specimens of Chandler's species were also present.

A comparison of commonly occurring metazoan parasites in the digestive tract was made between common eiders, Somateria mollissima, that were contaminated with oil and reference birds confiscated from illegal hunting. There was a greater number of commonly occurring parasites and their abundance in reference than in oiled eiders. Except for an acanthocephalan, Polymorphus botulus, which was embedded in the wall of the intestinal tract, most of the other taxa of parasites, including trematodes, cestodes and nematodes, were probably voided from the birds following ingestion of oil. Reference eiders harboured fewer species and a substantially lower mean abundance of parasites than those studied in Newfoundland and Labrador more than four decades ago; this may be a signal of a changing prey base or an increase in prey availability as winter ice cover continues to decline.

Neglected tropical diseases (NTDs) share certain traits: they are parasitic infections, prevailing in tropical environments and affecting marginalized sectors of the population. Six NTDs – ascariasis, cysticercosis, echinococcosis, hookworm infection, onchocerciasis and trichuriasis – all of them endemic in Latin America and the Caribbean (LAC), are analysed in this work. This review aims to discuss key information on the function of excretory/secretory (E/S) proteins from these parasites in their infectivity, pathogeny and diagnosis. The modulation of the host immune system to favour the permanence and survival of the parasite is also discussed. An updated knowledge on the function of E/S molecules in endemic parasitoses in LAC may lead to new approaches for the clinical management and diagnosis of these diseases. In turn, this could allow us to optimize their treatment and make it more affordable – a relevant goal given the economic constraints that the region is facing.

An annotated checklist of the cestode parasites of Argentinean wild birds is presented, as the result of a compilation of parasitological papers published between 1900 and April 2021. This review provides data on hosts, geographical distribution, sites of infection, location of material deposited in helminthological collections, references and taxonomic comments. A host/parasite list is also provided. During this period, 38 papers were published that gather information about 34 cestode nominal species and 11 taxa identified at generic level, belonging to three orders, ten families and 35 genera. The highest number of cestode taxa was recorded in the family Hymenolepididae, with 12 nominal species and two taxa identified at generic level, followed by Dilepididae, with eight nominal species and three taxa identified at generic level. Of the 1042 species of birds reported in Argentina, only 29 (2.8%) were reported as hosts of adult cestodes. The families of birds with the highest number of reported taxa were Laridae and Anatidae, with 20 and 14 taxa, respectively.