Balantidium honghuensis n. sp. (Ciliophora: Trichostomatidae) from the Rectum of Rana nigromaculata and R. limnocharis from Honghu Lake, China

A new trichostome ciliate, Balantidium honghuensis n. sp., was isolated from the recta of Rana nigromaculata and R. limnocharis during parasite surveys in Honghu Lake, Hubei Province, central China in summer of 2010 and 2011. Its detailed morphometric characters based on LM and SEM studies were described herein. The organism is oval in shape and thickly ciliated. The vestibulum is "V" shaped and occupies about 1/3 to 2/5 of the body length. The vestibular and nearby regions possess strong peripheral fibers which form a marked axial fiber about the cytopharynx. More than 10 contractile vacuoles are distributed along the periphery of the latter body. Comparisions were made between this new species and B. sinensis Nie, 1935. They were discriminated from each other in terms of general body forms, body size, and vestibulum shapes. Besides, special attention was paid to its high-speed daughter swarmers which we believed to be the infective stage of B. honghuensis. Possible infection routes of anura amphibian balantidia were discussed.

Discovery of Larval Gnathostoma nipponicum in Frogs and Snakes from Jeju-do (Province), Republic of Korea

A survey was performed to find out the intermediate hosts of Gnathostoma nipponicum in Jeju-do (Province), the Republic of Korea. In August 2009 and 2010, a total of 82 tadpoles, 23 black-spotted pond frogs (Rana nigromaculata), 7 tiger keelback snakes (Rhabdophis tigrinus tigrinus), 6 red-tongue viper snakes (Agkistrodon ussuriensis), and 2 cat snakes (Elaphe dione) were collected in Jeju-do and examined by the pepsin-HCl digestion method. Total 5 gnathostome larvae were detected in 3 (50%) of 6 A. ussuriensis, 70 larvae in 3 of 7 (42.9%) R. tigrinus tigrinus, and 2 larvae in 2 of 82 (8.7%) frogs. No gnathostome larvae were detected in tadpoles and cat snakes. The larvae detected were a single species, and 2.17x0.22 mm in average size. They had characteristic head bulbs, muscular esophagus, and 4 cervical sacs. Three rows of hooklets were arranged in the head bulbs, and the number of hooklets in each row was 29, 33, and 36 posteriorly. All these characters were consistent with the advanced third-stage larvae of G. nipponicum. It has been first confirmed in Jeju-do that R. nigromaculata, A. ussuriensis, and R. tigrinus tigrinus play a role for intermediate and/or paratenic hosts for G. nipponicum.

Helminth parasites of green toad, Bufo viridis [Anura: Bufonidae], tree frog, Hyla arborea savignyi [Anura: Hylidae] and marsh frog, Rana ridibunda ridibunda [Anura: Ranidae] from southwest of Iran

A total of 108 toads and frogs were collected by hand from January to August 1994 from different sites in the southwest of Iran, mainly from Khouzestan province. Among 79 green toads [Bufo viridis], 93.7% were infected with one or more parasite species. There was no significant difference between snout-ventral lengths [SVL] of infected [n = 74] and uninfected [n = 5] toads [P = 0.323; Student's t-test], also between the rate of infection in males and females [P = 0.392; chi 2 test]. Helminth parasites of B. viridis were the monogenean, Polystoma viridis, the digenean, Haplometra cylindracea the cyclophyllid cestodes, Nematotaenia dispar; Diplopylidium acanthotetra cysticercoid and the nematodes, Cosmocerca ornata, Cosmocerca commutata, Rhabdias bufonis and Aplectana sp. There was no significant difference between the rate of infection with P. viridis [chi 2 = 1.92, P = 0.166] and N. dispar [chi 2 = 0.032, P = 0.859] in males and females. Males [n = 12], however, were significantly more infected [chi 2 = 5.52, P = 0.019] with R. bufonis than females [n = 8]. SVL of B. viridis infected with N. dispar and uninfected samples were significantly different [P = 0.016]. No significant difference was shown for infection with P. viridis [P>0.05; Student's t-test]. Among 17 marsh frogs [Rana ridibunda ridibunda], 58.8% were infected with helminth parasites. There was no significant difference between SVL of infected [n = 10] and uninfected [n = 7] frogs [P = 0.238; Student's t-test] and also between uninfected males and females using [P = 0.201; chi 2 test]. Metacercarian cysts of digenetic trematode Codonocephalus urniger and the nematode Aplectana sp. were found in Rana ridibunda ridibunda specimens. Twelve true tree frogs, Hiyla arborea savignyi were examined. The monogenean, Polystoma viridis, the cyclophyllid cestode, Nematotaenia dispar and the nematode, Aplectana sp. were found in the tree frogs

Experimental infection of Gnathostoma spinigerum larvae in prawns and tadpoles.

Naturally captured Lanchester's freshwater prawns (Macrobrachium lanchesteri) and farm-bred Rana regulosa tadpoles were assessed for their capability of being the first or second intermediate hosts of Gnathostoma spinigerum. Seventy specimens from each animal group were randomized into a control group and investigated for larvae of G. spinigerum by pressing them between two pieces of glass and examination under stereomicroscope. No Gnathostoma larvae were found in the entire control group. Another 120 specimens of each animal were used in two treatment groups; 60 being exposed to the first-stage larvae, G. spinigerum, and 60 exposed to cyclops containing the third-stage larvae for 7 days. No larvae of G. spinigerum were found in the prawns of both treatment groups that resembled tadpoles exposed to the first-stage larvae. In contrast, 18.3% of tadpoles, which were exposed to cyclops containing third-stage larvae, were infected. Lanchester's freshwater prawns cannot serve as intermediate host of G. spinigerum, while R. regulosa can serve as the second intermediate host.

Planorbid snails as potential molluscan intermediate host of a human intestinal fluke, Neodiplostomum seoulensis (Trematoda : Diplostomatidae) in Korea.

Three species of the pulmonate snails of the family Planorbidae have been reported from Korea; Gyraulus convexiusculus, Hippeutis (Helicorbis) cantori and Segmentina (Polypylis) hemisphaerula. Of these 3 species, only H. cantori is reported as the molluscan intermediate host of Neodiplostomum seoulensis, one of the important snail-borne human intestinal trematodes in Korea. However, S. hemisphaerula was also found to be an intermediate host for N. seoulensis. In field-collected snails, H. cantori and S. hemisphaerula were found shedding bifurcated cercariae of N. seoulensis, whereas no G. convexiusculus was found shedding cercariae. In experiments with laboratory-bred snails, only S. hemisphaerula was susceptible to miracidia of N. seoulensis. Tadpoles of Rana nigromaculata and R. rugosa were exposed to cercariae shed from field-collected and laboratory-bred S. hemisphaerula. All tadpoles of R. nigromaculata were found to be massively infected, but none of the tadpoles of R. rugosa were infected with larvae of N. seoulensis. Metacercariae from tadpoles of R. nigromaculata and the snake Rhabdophis tigrinus tigrinus were fed to rats, and eggs of N. seoulensis were detected in the rat feces one-week later. These rats were killed and adult N. seoulensis recovered from the small intestines. This is the first report of S. hemisphaerula as a molluscan intermediate host for N. seoulensis in Korea.

Spargana infection of frogs in Malaysia.

Frogs caught from two States (Selangor and Langkawi) in Malaysia were examined for spargana of Spirometra sp. Infected frogs usually show no marks of infection but some had swelling and bleeding at the infection site. The size and weight of the infected frogs did not correlate with the infection status. The infection status in relation to human health is discussed.