Results of the incorporation of carbon from 14C-glycerol into total, polar and nonpolar lipids in Haemonchus contortus (Nematoda: Trichostrongylidae) reveal that the radioactivity lost into the medium as lipids decreased during the first 3 h of incubation. This was followed by a drastic increase during the 4th h. Again, there was a decline by 75% during the 5th h. However, there was a slight increase in the nonpolar lipids during the 5th h.

The use of 75Selenomethionine labelled cercariae of Schistosoma mansoni for ultrastructural localization of parasites in host tissues has been evaluated. Both gamma counting of tissue, and autoradiography of resin-embedded tissue were successful. The autoradiographic technique was more sensitive and schistosomula were readily located in pulmonary tissue up to 24 days post-infection.

Pulmoverminae is proposed as a new subfamily within the Hemiuridae Lühe, 1901, to receive the genera Pulmovermis Coil and Kuntz, 1960 and Hydrophitrema Sandars, 1960. The genera are compared, and considered to be distinct.

In the experiments carried out by Nishigori (1925) and Saito (1925) on the life-history of Hepaticola hepatica it was shewn that this parasite does not reach maturity when a rabbit is artificially infected with embryonated eggs. It is true that the worms shewed some development, but after a time they disappeared leaving only nodules of connective tissue. In view of these results it may be of interest to record a case, observed by the writer where a rabbit carried a natural infection.

Comparative efficacy of mebendazole and flubendazole, a p−fluor analogue of mebendazole against the encysted larvae of Trichinella spiralis (USA strain) in the diaphragm of mice and rats were studied in order to provide a better understanding of the structure-activity relationship within the benzimidazole series. Drugs given 10–100 mg/kg/day for 3 consecutive days (35–37 days post-infection) or at 300 mg/kg, 35 days post infection were significantly effective in decreasing early encysted larvae in mice. No significant differences in effectiveness against the early encysted larvae could be observed between the drugs under the present experimental conditions. Mebendazole was found to be more effective that flubendazole in decreasing old encysted larvae in mice treated 70–72 days post-infection based on a comparative study of their ED50 values. When rats were given the drugs at the dose of 10 mg/kg/day for 3 consecutive days, mebendazole was significantly effective against both early and old encysted larvae while flubendazole was not.

Sporocysts capable of producing active miracidia were recovered from the upper branchial chamber of the snail species, Melania tuberculata and M.scabra. The non-ocellate miracidium was characterised by the presence of 22 epidermal plates in four tiers, an apical gland with four nuclei and two penetration glands. Sporocysts were of two types, one producing active miracidia and the other in which daughter sporocysts and miracidia were found. These sporocysts were characterised by the presence of bunches of circular muscles at intervals and also by the presence of a network of muscle fibres at the anterior and posterior one fifth regions. Development of the miracidia took place in compartments. Histochcmical tests were carried out as regards glycogen, protein, lipids and phosphomonoesterases.

The specimens used for this study were obtained from two collections of helminths sent to the Commonwealth Institute of Helminthology for identification. The first was made by Dr. R. Sachs in his survey of parasitic infestation of wild herbivores in the Serengeti region, Tanzania and the second by Dr. L. D. Fay in a veterinary survey of game animals in Kenya.

Ocular lesions have been reported in patients with schistosomiasis; however, the problem with studying schistosomal infection of the human eye is that biopsies are almost impossible to take, and histopathological examination of suspicious lesions can only be undertaken post-mortem or after enucleation. This work aimed to study the possible effects and pathogenesis of schistosomiasis on the eye. This study involved 55 hamsters; five hamsters remained non-infected and the remaining 50 hamsters were infected with Schistosoma mansoni cercariae. Infected hamsters were sacrificed on weeks 8, 12, 16 and 20 post-infection (pi). Eye sections were prepared and stained for histopathological and immunohistochemical studies. Histopathological changes detected in hamsters infected after 16 and 20 weeks included looseness and oedema of the innermost retinal layers together with hyperplastic polypoid growth. Neither eggs nor granulomata were detected in eye sections throughout the experimental period. Deposition of S. mansoni antigen was revealed in 35% of infected hamsters. Later, on weeks 16 and 20 pi, moderate subepithelial conjuctival deposits and marked subchoroidal and scleral deposition were detected. In conclusion, the deposition of schistosomal antigen and immune complexes may play a pivotal role in the ocular changes that occur in schistosomiasis, even in the absence of detectable Schistosoma eggs. Schistosomiasis should be suspected in cases with unexplained ophthalmological findings, especially in endemic areas.

Two new species of Diaphorocleidus and one new species of Rhinoxenoides n. gen. are described from the gills of Acestrorhynchus falcatus (Bloch) from rivers of north-eastern Pará, Brazil. Diaphorocleidus jaymedeloyolai n. sp. is characterized by a male copulatory organ (MCO) possessing three counterclockwise coils; similar anchors with subtriangular superficial roots; a ventral bar with posteromedial projection; and hooks of pairs 1, 4 and 7 approximately three times longer than hook pair 5. Diaphorocleidus sclerocolpus n. sp. differs from its congeners by a dual-branched accessory piece articulated with the MCO and a sclerotized tubular vagina with a bottle-shaped vestibule. Rhinoxenoides n. gen. is proposed and is characterized by possessing: MCO sclerotized with clockwise coils; an accessory piece articulated to the base of MCO; a sinistroventral vaginal aperture; ventral anchor with conspicuous roots; dorsal anchor with superficial root five times longer than deep root; and absence of dorsal bar. The proposal of Rhinoxenoides n. gen. is also supported by its phylogenetic relationship with Protorhinoxenus prochilodi and species of Rhinoxenus, using 16 morphological characters, which resulted in the following hypothesis of sister-group relationships: Rhinoxenoides n. gen. [Protorhinoxenus (Rhinoxenus curimatae (R. nyttus (R. bulbovaginatus (R. guianensis, R. piranhus, R. euryxenus (R. arietinus, R. anaclaudiae)))))].

Androgens have been shown to exert a cysticidal effect upon Taenia crassiceps, an experimental model of cysticercosis. To further inquire into this matter, the Taenia crassiceps model was used to evaluate the expression of several proteins after testosterone (T4) and dihydrotestosterone (DHT) in vitro treatment. Under 2-D proteomic maps, parasite extracts were resolved into approximately 130 proteins distributed in a molecular weight range of 10–250 kDa and isoelectrical point range of 3–10. The resultant proteomic pattern was analysed, and significant changes were observed in response to T4 and DHT. Based on our experience with electrophoretic patterns and proteomic maps of cytoskeletal proteins, alteration in the expression of isoforms of actin, tubulin and paramyosin and of other proteins was assessed. Considering that androgens may exert their biological activity in taeniids through the non-specific progesterone receptor membrane component (PGRMC), we harnessed bioinformatics to propose the identity of androgen-regulated proteins and establish their hypothetical physiological role in the parasites. These analyses yield a possible explanation of how androgens exert their cysticidal effects through changes in the expression of proteins involved in cytoskeletal rearrangement, dynamic vesicular traffic and transduction of intracellular signals.

Largemouth bass, Micropterus salmoides, is a native fish species with special importance for sport fishing competitions in Nuevo León, Mexico. However, no study has investigated the parasitic fauna of M. salmoides, and no reports are available on monogenean parasites in this fish species. Therefore, we described the monogenean parasites of M. salmoides and the effects of season and fish condition factor in five reservoirs: La Boca (LB), El Cuchillo–Solidaridad (CS), Sombreretillo (S), Laguna Salinillas (LS) and Cerro Prieto (CP). The monogeneans infecting M. salmoides were Clavunculus unguis and Acolpenteron ureteroecetes (collected in all localities), as well as Syncleithrium fusiformis, Haplocleidus furcatus, Clavunculus bifurcatus and Urocleidus principalis (CS). Clavunculus unguis had the highest prevalence in fish from all reservoirs. The abundance of monogeneans was generally greater in late spring to autumn than in winter. Although season was not correlated with abundance (rs = 0.0934, P <  0.0154), the months of highest temperature (from May to September) were positively correlated with parasite abundance. A significant association was observed between fish condition factor and the presence of monogeneans (P <  0.05), except for A. ureteroecetes. Our findings include five new geographic records for C. unguis, S. fusiformis, H. furcatus and C. bifurcatus.

The phylogenetic relationships of 42 species of cloacinine nematodes belonging to three tribes (Coronostrongylinea, Macropostrongylinea and Zoniolaiminea) were examined based on sequence data of the first and second internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. All nematodes examined are parasites of Australian macropodid marsupials. None of the three nematode tribes was monophyletic. Paraphyly was also encountered in three genera: Papillostrongylus, Monilonema and Wallabinema. Species within the genus Thallostonema were limited to a single host genus (i.e. Thylogale), whereas species within the five principal genera (Coronostrongylus, Macropostrongylus, Popovastrongylus, Wallabinema and Zoniolaimus) were found to occur in multiple host genera. Potential modes of evolution among these nematodes are discussed.

By means of scanning electron microscopy, stalked protrusions were observed arising from the outer surface of intact brood capsules of Echinococcus granulosus. Histological studies showed these protrusions to be developing protoscoleces. However, complete development is not attained and the protoscoleces eventually die. It is suggested that external development is a result of overcrowding within the brood capsule.

Polyonchobothrium scleropagis (Cestoda: Pseudophyllidea) is described as a new species from the Australian osteoglossid fish Scleropages leichardti Günther.

The complete gene encoding an immunodominant antigen of Dirofilaria immitis was isolated from a Charomid 9–36 genomic DNA library. This genomic DNA clone termed ‘Dg2’ was characterized by restriction mapping, DNA sequencing of the 5′ flanking region, the exon/intron boundaries and the polyadenylation addition site. The Dg2 with 4872 bp in length consisted of five exons interspersed with four introns. These exons reveal a single open reading frame followed by a long 3′ non-coding region of 1383 bp. The open reading frame of 969 bp encodes a polypeptide of 322 amino acids with a molecular weight of 34,400. The ATG translation initiation codon starts 22 nucleotides downstream from the 5′ end of the first exon. The polyadenylation signal sequence, AATAAA, is located at the 3′ end of the last exon. The transcription initiation site was determined by primer extension technique. S1 nuclease mapping analysis demonstrated that the primary transcript derived from Dg2 is synthesized in microfilariae but not in male or female adult worms. The result suggests that the stage-specific expression of Dg2 is regulated at the level of primary transcript.

The identity and status of the nematode described by van Breda de Haan (1902) from the roots of diseased rice plants in the Dutch East Indies under the name of Tylenchus oryzae have remained more or less conjectural owing to the inadequacy of the original description and the absence of any drawings showing its appearance and structure. The present writer was so doubtful of its validity as a species that in his monograph on the genus Anguillulina (1932) he listed it under “species inquirendae.” In April 1934, Dr. J. van der Vecht of the Institute of Plant Diseases, Buitenzorg, Java, visited this Institute and in the course of conversation informed the writer that in his opinion the species was a valid and distinct one. He kindly promised that on his return to Buitenzorg he would collect specimens of the parasite and forward them for examination. In due course a good number of adult specimens, preserved in 5% formalin, were received and on these it has been possible to base the observations embodied in the following pages. The writer desires to express his thanks to Dr. P. van der Goot, Director of the Institute of Plant Diseases, Buitenzorg and to Dr. van der Vecht for their kindness in making this interesting material available for investigation.

The structure of the female reproductive tract, and the patterns of oogenesis, fertilization and embryogenesis were examined from two adult female Loa loa (Nematoda: Filarioidea) from Gabon. They were found to be indistinguishable in the two specimens, and almost indistinguishable from the pattern previously described from Dirofilaria immitis, except in chromosome number. Loa loa has 2n=10+X0.

We describe two new species of monogenean parasites of the genus Gyrodactylus von Nordmann, 1832 infecting Neotropical catfishes (Siluriformes) in southern Mexico: Gyrodactylus chulini n. sp. from ‘chulín’, Rhamdia laticauda collected in Oaxaca; and Gyrodactylus juili n. sp. from ‘juil’, Rhamdia guatemalensis from Veracruz. Morphologically, both new taxa are similar to Gyrodactylus spp. infecting catfishes (Siluriformes) in South America. Sequences of the internal transcribed spacers (ITS1-5.8S–ITS2 rDNA), the D2+D3 domains of the large ribosomal subunit (28S rDNA) and the cytochrome oxidase II (COII) gene were obtained from multiple parasite specimens and analysed using Bayesian inference. Phylogenetic hypotheses using ITS rDNA and COII genes, recovered two new Gyrodactylus species from Rhamdia spp.: G. chulini n. sp.; and Gyrodactylus juili n. sp., which are sister species to Gyrodactylus lilianae, a parasite of Rhamdia quelen in Brazil, and show strong affinity to other gyrodactytlids infecting Neotropical catfishes. This suggests that these new taxa, the first gyrodactylids described from Rhamdia spp. in Mexico, co-migrated to Tropical Middle America with their Neotropical catfish hosts, after the emergence of the Isthmus of Panama.

Helminthological studies may contribute with valuable information on host biology and conservation. Herein, we provide new data on helminths infecting the lizard Norops fuscoauratus, testing one of the factors considered most important in parasitic ecology: host size. We analysed 25 specimens of N. fuscoauratus from three highland marshes in the Brazilian semi-arid. Eight taxa of helminths belonging to Nematoda, Trematoda and Acanthocephala were found. Physaloptera sp. showed the higher prevalence (40%), with a mean intensity of infection of 3.3 ± 1.46 (1–16) and mean abundance 1.32 ± 0.65 (0–16). Norops fuscoauratus represents four new host records for the helminths Cyrtosomum sp., Pharyngodon travassosi, Strongyloides sp. and Centrorhynchus sp. There is no relationship of host body size (P = 0.79) and mass (P = 0.50) with parasite richness. In addition, the present study contributes to the knowledge of the parasitic fauna of N. fuscoauratus and the Neotropical region.

The prevalence of vector-associated parasitic infections is high in central-southern Italy. The deltaic coastal plain of the Volturno River has been suspected, by veterinary practitioners, to have a high accidental incidence of Dirofilaria repens. Thus, the goal of this study was to evaluate the prevalence of dirofilariasis and other coinfections frequently described in dogs living in the Volturno area. Blood samples of 100 clinical asymptomatic dogs were examined using a Knott's technique and polymerase chain reaction in order to identify microfilariae. Other vector-borne coinfections were also investigated using ELISA kits. The results were analysed using statistical and Geographic Information System (GIS) software. Microfilariae of D. repens were detected in 10% of the dogs surveyed, with a presence of antibodies against Ehrlichia canis (4/10) and Dirofilaria immitis (1/10). Such high incidence should be considered in light of the zoonotic potential for D. repens and the support for more regular use of repellents to prevent the spread of this disease. The GIS analyses indicated that the study area provides suitable conditions to sustain populations of mosquito vectors and D. repens parasites throughout much of the year.