Acanthoparyphium shinanense n. sp. (Digenea: Echinostomatidae) from Experimental Chicks Infected with Metacercariae Encysted in Brackish Water Clams in the Republic of Korea

Acanthoparyphium shinanense n. sp. (Digenea: Echinostomatidae) is described from chicks experimentally infected with the metacercariae encysted in 2 brackish water clam species, Ruditapes philippinarum and Coecella chinensis, in the Republic of Korea. The metacercariae were round to oval, armed with 23 collar spines, and 0.216 (0.203-0.226) mm in diameter. From 5 chicks experimentally infected each with 200 metacercariae, 34 juvenile (5-day-old worms) and 104 adult flukes (7-day-old worms) were harvested from their small intestines, with the average worm recovery rate of 13.8%. The adult flukes were 3.18 (2.89-3.55) mm long and 0.68 (0.61-0.85) mm wide, with an elongated, posteriorly tapering body, and a prominent head collar armed with 23 collar spines arranged in a single uninterrupted row. The posterior testis of A. shinanense was longitudinally elongated, which is similar to Acanthoparyphium spinulosum Johnston, 1917 but unique from the other closely related species, including Acanthoparyphium tyosenense Yamaguti, 1939, Acanthoparyphium kurogamo Yamaguti, 1939, and Acanthoparyphium marilae Yamaguti, 1934. The eggs of A. shinanense were larger than those of A. spinulosum, and the anterior extent of 2 lateral groups of vitellaria was slightly more limited in A. shinanense than in A. spinulosum. Molecular analysis of nuclear and mitochondrial genes revealed low homology with A. spinulosum from USA (96.1% in 5.8S rRNA) and Ukraine (97.9% in 28S rRNA), Acanthoparyphium n. sp. from USA (98.0% in 28S rRNA), and Acanthoparyphium sp. from Australia, Kuwait, and New Zealand. Biological characteristics, including its first intermediate host and natural definitive hosts, as well as its zoonotic capability, should be elucidated.

Establishing infection with Echinococcus granulosus hydatid cyst From Bovine origin in dogs

Establishing infection with Echinococcus granulosus had often created a challenge where by the actual role of the different Intermediate hosts could not be precisely determined. This study was consequently planned to examine the efficiency of cattle as intermediate hosts in the transmission of E. granulosus to canine final hosts. A modified procedure was followed where dogs were fed whole viable hydatid cysts as compared to viable protoscoleces obtained from hydatid sand mixed with meat. Successful transmission was attained as indicated by the presence of ova at faecal examination and adult worm recovery at post – mortem examination. The pre-patent period ranged between 30 – 42 days. It was apparent that the non capsulated protoscoleces were defected to the extend that they could not develop to maturity in the dog’s viscera. This modification needs to be applied to verify the efficiency of different intermediate hosts in the transmission cycle of Echinococcosis.

Electroacupuncture in Rats Infected with Strongyloides venezuelensis: effects on gastrointestinal transit and parasitological measurements

Objective To investigate the effects of electroacupuncture (EA) at ST36 and CV12 on gastrointestinal transit and parasitological measurements during Strongyloides venezuelensis infection in rats. Design Rats were infected with S. venezuelensis and allocated to one of three groups that were infected and remained untreated (SV group, n=8), infected and treated with EA at CV12 (SV+CV12 group, n=8) or infected and treated with EA at ST36 (SV+ST36 group, n=8). EA was performed every 3 days over a 21-day period, at 4 mA intensity and 15 Hz frequency for 20 min. At 2 and 20 days post-infection (dpi), body weight, food and water intake, and faecal characteristics were monitored over a 24-hour period. Gastric emptying, caecal arrival time, small intestinal transit and eggs per gram (EPG) of faeces were calculated at 3, 9, 15 and 21 dpi. At 21 dpi, intestinal worm recovery was counted. Results EA at ST36 and CV12 slowed gastric emptying over the course of infection time. An accelerated intestinal transit was observed in the ST36 group, and after CV12 treatment the same effect was observed at 9 and 15 dpi. At 9 dpi, EPG was increased in the CV12 group. ST36 treatment decreased EPG at 9 and 15 dpi. At 21 dpi, both the ST36 and CV12 groups had increased EPG and worm numbers. No changes were observed in the other parameters analysed. Conclusions EA at ST36 and CV12 provoked changes in gastrointestinal transit that may be beneficial to the host during S. venezuelensis infection; however, based on the number of worms and EPG at 21 dpi, the indication for EA in the treatment of strongyloidiasis needs to be carefully assessed.

Anthelmintic effects of forage chicory (Cichorium intybus) against gastrointestinal nematode parasites in experimentally infected cattle

SUMMARYTwo experiments studied the effects of dietary chicory against gastrointestinal nematodes in cattle. In Experiment (Exp.) 1, stabled calves were fed chicory silage (CHI1;n= 9) or ryegrass/clover hay (CTL1;n= 6) with balanced protein/energy intakes between groups. After 16 days, all calves received 10 000Ostertagia ostertagiand 66 000Cooperia oncophorathird-stage larvae (L3) [day (D) 0 post-infection (p.i.)]. In Exp. 2, calves were assigned to pure chicory (CHI2;n=10) or ryegrass/clover (CTL2;n= 10) pastures. After 7 days, animals received 20 000O. ostertagiL3/calf (D0 p.i.) and were moved regularly preventing pasture-borne infections. Due to poor regrowth of the chicory pasture, CHI2was supplemented with chicory silage. At D40 p.i. (Exp. 1) and D35 p.i. (Exp. 2) calves were slaughtered for worm recovery. In Exp.1, fecal egg counts (FEC) were similar between groups. However,O. ostertagicounts were significantly reduced in CHI1by 60% (geometric mean;P< 0·01), whereasC. oncophoraburdens were unaffected (P= 0·12). In Exp. 2, FEC were markedly lowered in CHI2from D22 p.i onwards (P< 0·01).Ostertagia ostertagiadult burdens were significantly reduced in CHI2by 66% (P< 0·001). Sesquiterpene lactones were identified only in chicory (fresh/silage). Chicory shows promise as an anti-Ostertagiafeed for cattle and further studies should investigate its on-farm use.

Partial resistance to homologous challenge infections of the digenean Echinostoma caproni in ICR mice

In the present paper, we analyse the effect of a primary infection of ICR mice with Echinostoma caproni (Trematoda: Echinostomatidae) on the generation of resistance against homologous challenge infections. In ICR mice, E. caproni induces chronic infections concomitantly with strong responses characterized by the development of T-helper 1 (Th1)-type local immune responses with elevated levels of local interferon-gamma (IFN-γ) and inflammatory and antibody responses. Here, the effect of the response generated against a primary infection with E. caproni in the generation of resistance against subsequent homologous infections was analysed. For this purpose, ICR mice were challenged with metacercariae of E. caproni and the results obtained showed that primary infection induces partial resistance against subsequent homologous infections in ICR mice. This resistance was expressed as a reduced rate of infection, worm recovery and worm size, indicating that primary infection induces changes in the host, making a hostile environment for the development of the parasite.

Diagnosis of the strongyloid nematodeStrongyloides venezuelensisin experimentally infected rats

Strongyloides venezuelensisis an intestinal nematode of rats, frequently used as a model for studying human and animal strongyloidiasis. In the present study, we evaluated parasitological, serological and molecular methods for the diagnosis of experimentalS. venezuelensisin rats,Rattus norvegicus. Blood and faecal samples were collected and analysed up to 60 days post infection (pi) with adult worm recovery occurring from 5 to 45 days pi. Using an enzyme-linked immunosorbent assay (ELISA), serum levels of IgG antibodies increased up to 28 days pi, thereafter decreasing by day 60 pi. Polymerase chain reaction (PCR) assays detectedS. venezuelensisDNA in faecal samples of rats from 5 to 21 days pi. The present study therefore represents the first step towards improving the diagnosis of experimental strongyloidiasis.

Identifying phenotypes involved in susceptibility to Schistosoma mansoni infection in F1B6CBA mice

Schistosomiasis is a disease with a strong genetic component influenced by socioeconomic and ecological factors. Epidemiological studies have identified several genetic regions involved in the schistosomiasis susceptibility. However, it is not well known what physiological traits are predisposing to the disease. The study of experimental infections in inbred mouse strains with variable genetic susceptibility to the disease offers a good opportunity to tackle this question. F1B6CBA hybrid between the most divergent strains was infected in order to characterize the immunophenotypes that correlate with the susceptibility of schistosomiasis disease in mice. Complete blood counts and immunophenotype were determined at 0, 3, 6, and 9 weeks post infection. Nine weeks after cercariae exposure, animals were perfused and worm recovery was assessed. A large number of hepatic lesions, a reduction in the eosinophil and basophil count in the acute phase of infection and the decreased number of monocytes, neutrophils and B-lymphocytes are phenotypes associated with increased susceptibility to S. mansoni infection.