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A description of Lecithocladium invasor n.sp. (Digenea: Hemiuridae) and the pathology associated with two species of Hemiuridae in acanthurid fish.

Lecithocladium invasor n.sp. is described from the oesophagus of Naso annulatus, N. tuberosus and N. vlamingii on the Great Barrier Reef, Australia. The worms penetrate the oesophageal mucosa and induce chronic transmural nodular granulomas, which expand the full thickness of the oesophageal wall and protrude both into the oesophageal lumen and from the serosal surface. We observed two major types of lesions: large ulcerated, active granulomas, consisting of a central cavity containing a single or multiple live worms; and many smaller chronic fibrous submucosal nodules. Small, identifiable but attenuated, worms and degenerate worm fragments were identified within some chronic nodules. Co-infection of the posterior oesophagus of the same Naso species with Lecithocladium chingi was common. L. chingi is redescribed from N. annulatus, N. brevirostris, N. tuberosus and N. vlamingii. Unlike L. invasor n.sp., L. chingi was not associated with significant lesions. The different pathenogenicity of the two species in acanthurid fish is discussed.

Animals↗

[A case of human infection with Clinostomum sp].

The genus Clinostomum is a cause of parasitic laryngo-pharyngitis. We report the 15th case of Clinostomum sp. infection in Japan. A 29-year-old female visited our hospital because of throat discomfort and expectoration of a worm by sneezing on November 17, 1997. The pharyngitis was caused by the worm. The worm was morphologically identified as the adult of the genus Clinostomum.

Adult↗

Natural infections of Clinostomum complanatum (Trematoda: Clinostomatidae) in wild herons and egrets, Tottori Prefecture, Japan.

Nycticorax nycticorax, Ardea cinerea, Egretta garzetta, and Egretta intermedia were naturally infected with Clinostomum complanatum (Trematoda: Clinostomatidae) among fourteen wild herons, seven wild egrets and one wild bittern evaluated at the Veterinary Hospital of Tottori University, Tottori, Japan. The latter three species of heron and egrets are reported for the first time as definitive hosts of this parasite in Japan.

Animals↗

[Preliminary study on the ecology of Trichobilharzia cercariae in the Huaihe river system].

OBJECTIVE: To investigate the ecological habit and characteristics of Trichobilharzia cercariae in the Huaihe river system. METHODS: During June of 2002-May of 2003, Radix auricularia snails were collected monthly in Yaohe Fishery of the branch of the Huaihe River. The cercariae, released from the positive snails and collected by Shade Drop Bottle, were examined by direct press. Ducklings were infected by cercariae with different ages and examined for the infection by miracidia hatching method. RESULTS: The results showed a typical seasonal fluctuation in infection rate of the snails, i.e. the cercariae detection rate was 0.81% in July, 0.65% in June, 0.07%-0.26% in April, May, August, September and October respectively, with a significant difference (chi2 = 26.73, P < 0.01). The release of cercariae from the snails showed a diurnal pattern in the natural conditions, with a significant peak between 8:00-12:00. It was proven that the main factors affecting the emerging of cercariae were temperature and light. The cercariae showed positively phototaxis. It was also showed that 50% mortality of the newly released cercariae between 18-25 degrees C occurred at 41 h, and all cercariae died within 52 h. The infectivity of cercariae was age-dependent. Under 18-25 degrees C, the highest infectivity was found at 0.5-8 h after emergence, then declined steadily to negative by 40 h post-emergence. CONCLUSION: The ecological characteristics of Trichobilharzia cercariae have been preliminarily verified in the Huaihe river system.

Animals↗

Population dynamics of Enterogyrus cichlidarum (Monogenea: Ancyrocephalinae) from the stomach of Tilapia spp. in Egypt.

In a 1-year seasonal study of the numbers of the stomach-inhabiting monogenean Enterogyrus cichlidarum in Tilapia nilotica in the River Nile, Egypt, prevalence and intensity reached a height in spring and infection levels were surprisingly high in winter. T. zillii harboured fewer parasites but seasonal changes were similar. No parasites were found in T. galilaea. The prevalence and intensity of the infection with E. cichlidarum rose significantly with increasing size of the host. Some of the possible reasons for these fluctuations are discussed. Immature enterogyrids were more abundant in the posterior sector of the stomach and adult enterogyrids showed a preference for the anterior sector. No significant difference was found in the numbers of enterogyrids in male and female hosts.

Animals↗

Epidemiological study of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (county), Korea.

The endemic status of clonorchiasis and metagonimiasis along the Geum-gang (River) in Okcheon-gun (County) in Korea was examined. From February to December 2000, stools of total 1,081 inhabitants living in 5 villages were examined. Each stool specimen was examined by both the cellophane thick smear method and the formalin-ether sedimentation technique. Egg-positive cases were further analyzed by Stoll's egg-counting technique, and praziquantel was administered to positive cases. The egg-positive rates for Clonorchis sinensis and Metagonimus species were 9.3% and 5.5%, respectively, and the double infection rate was 3.5%. The numbers of eggs per gram (EPG) of feces of C. sinensis and Metagonimus sp. were 918 +/- 1,463 and 711 +/- 947, respectively. The egg-positive rates for C. sinensis and Metagonimus sp. in the riverside area were 14.2% and 8.4%, respectively, which were significantly higher than those of the inland area (3.2% and 1.7%, respectively). The egg-positive rates of C. sinensis and Metagonimus sp. in males (16.7% and 10.0%) were significantly higher than those of females (3.5% and 1.8%). However, there were no significant differences of EPG values between localities and sexes. The prevalence of clonorchiasis and metagonimiasis in this survey was significantly lower than that in the previous reports. However, there is still a high prevalence of infection with C. sinensis and Metagonimus sp. in this region, especially in the riverside area.

Adolescent↗

Rare case of Metagonimus yokogawai.

Intestinal Heterophyid infections are almost unknown in India with only one documented case report. We report a case of six year old child with diarrhoea without any other associated gastrointestinal symptoms. Examination of the faeces revealed eggs of Metagonimus yokogawai. However, the patient left against medical advice and was lost to follow up. The case is being reported because of its rarity.

Animals↗

Haplorchis infections in intermediate hosts from a clonorchiasis endemic area in Meinung, Taiwan, Republic of China.

Snails and freshwater fish were examined from four ponds in the Meinung township in which Clonorchis sinensis was known to be endemic 18 years ago. No metacercariae were found in 478 Tilapia nilotica, whereas of 451 Ctenopharyngodon idellus examined, 16.2%, 3.3% and 0.9% were found to be infected with Haplorchis pumilio, H. taichui and Clonorchis sinensis, respectively. In addition, there were some unidentified metacercariae in 12.0% of Ctenopharyngodon idellus examined. Overall, no positive correlation between infection rates and sizes of infected fish was shown. Six species of snails were collected in this survey and two frequently-occurring snails, Melanoides tuberculata and Thiara granifera were commonly infected with H. pumilio. Reasons for the prevalence of Haplorchis species and the absence of Clonorchis sinensis in fish and snail hosts in a previously reported endemic area for human clonorchiasis are discussed.

Animals↗

Statistical modelling of the spatial distribution of prevalence of Calicophoron daubneyi infection in sheep from central Italy.

Statistical modelling for Disease Mapping and Ecological Analysis is of particular importance in veterinary parasitology because environmental characteristics can affect parasite distribution. However, the main difficulties relate to the concentration of animal populations within farms, which contrasts to the study of wild animal populations. In the present paper we report the results of a cross-sectional coprological survey designed to study the presence and distribution of the rumen fluke Calicophoron daubneyi--which causes paramphistomosis, a snail borne disease--in pastured sheep living in the Latina province of central Italy. We show how techniques derived from human epidemiology can be used to study the spatial distribution of parasite infection in animals. We proposed a hierarchical Bayesian model with random terms for unstructured variability (heterogeneity) to account for local farm characteristics and spatially structure terms (clustering) to cope with medium-large scale environmental characteristics.

Animal Husbandry↗

Investigations on the prevalence of Heterophyes species in twelve populations of the first intermediate host in Egypt and Sudan.

Twelve populations of the mud snail Pirenella conica from the densely populated Nile Delta, saline inland waters, and the scarcely populated coast of the Red Sea were investigated for the prevalence of Heterophyes heterophyes, H. aequalis, and H. dispar. Heterophyes heterophyes was most prevalent in the Nile Delta, which seems to be the centre of human heterophyiasis throughout the distributional range of that species. Transmission takes place near human settlements, where the definitive hosts are abundant. However, the compiled data from infected intermediate and definitive hosts show, that the prevalence of H. heterophyes in the Nile Delta is declining. The two other Heterophyes species of the Near East, which have not yet been recorded from humans, were absent (H. dispar) or almost absent (H. aequalis) from the Nile Delta, where they had been found frequently in the 1950s. However, they occurred at the coast of the Red Sea.

Animals↗

Enzyme-linked immunoelectrotransfer blot analysis of excretory-secretory proteins of Fascioloides magna and Fasciola hepatica.

Fasciola hepatica is a parasite of cattle (Bos taurus), but not of white-tailed deer (Odocoileus virginianus), while Fascioloides magna is a parasite of white-tailed deer which also infects cattle as dead-end host. Adult parasites were collected from naturally infected white-tailed deer or cattle. Excretory-secretory proteins (ESP) were obtained from each parasite. Protein banding patterns were analysed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and probed using sera from experimentally infected deer of cattle using enzyme-linked immunoelectrotransfer blot (EITB, also known as Western blot) analysis. Protein banding patterns of the two species were different. EITB analysis of Fascioloides magna ESP using sera from Fascioloides magna infected deer or cattle identified three bands of approximately 17, 22 and 27 kDa of which the 27 kDa antigen cross-reacted with sera from Fasciola hepatica infected cattle. EITB analysis of Fasciola hepatica ESP probed with sera from Fasciola hepatica infected cattle identified three bands of approximately 15, 26 and 46 kDa. The 46 and 26 kDa ESP cross-reacted with sera from Fascioloides magna infected cattle, but not with sera from Fascioloides magna infected deer. The band at 15 kDa which reacted specifically for Fasciola hepatica infected cattle sera consisted of two protein bands close to each other as seen on the SDS-PAGE gel. The EITB reaction at approximately 17 kDa and 22 kDa of Fascioloides magna ESP, and at approximately 15 kDa of Fasciola hepatica ESP can be used for species specific diagnosis.

Animals↗

Population dynamics of the monogenean Anoplodiscus cirrusspiralis on the snapper, Pagrus auratus.

Populations of Anoplodiscus cirrusspiralis were monitored for 1 year on tagged individual snapper in experimental cages kept in a large on-shore pond with flow-through filtered sea water. The cages were stocked with small and large fish at either low or high initial density. Irrespective of size and density, snapper with light initial infections maintained light infections, whereas fish with heavy initial infections showed fluctuations in parasite population size throughout the year. These data indicate that some snapper have an innate resistance to infection by A. cirrusspiralis, with little evidence for acquired immunity induced by heavy infection. Parasite longevity was greater on the pectoral fin than caudal fin, and greater on large than small fish irrespective of fish density; longevity was greater on susceptible fish than on resistant fish. Recruitment and mortality rates were greater on the pectoral fin and in low density cages, but were influenced by fork length.

Animals↗

The occurrence of the intestinal fluke Sphaeridiotrema globulus in domestic ducks in New South Wales.

A mortality in muscovy ducklings caused by infection with the intestinal fluke, S. globulus, is described. The disease was characterised by depression, anorexia, wasting, diarrhoea and high mortality. The major pathological lesions were associated with the attachment sites of the flukes and consisted of severe enteritis with ulceration, principally affecting the jejunum, but also involving the duodenum and ileum. Experimental infections were produced in ducklings by oral administration of either G. austrialis infected with S. globulus metacercariae or S. globulus metacercariae or S. globulus metacercariae. The small, dextral, operculate snail G. australis was identified as the intermediate host and G. australis and an unidentified planorbid as transport hosts. L. tomentosa was also able to be a transport host. The epidemiology of the outbreak and aspects of acquired resistance are presented.

Animals↗

Host specificity of Austropeplea ollula (Gastropoda: Lymnaeidae) to miracidial infection with a human intestinal fluke Neodiplostomum seoulense (Trematoda: Diplostomatidae) in Korea.

Three species of freshwater pulmonate snails of Lymnaeidae have been reported from Korea, Radix auricularia coreana, Austropeplea ollula, and Fossaria truncatula. Of these 3 species, only A. ollula was naturally infected with Neodiplostomum seoulense cercariae (prevalence, 0.3%). In experiments with the laboratory-reared snails, A. ollula was found to be susceptible to the N. seoulense miracidia (prevalence, 10%). This is the first report of A. ollula as the first molluscan intermediate host for N. seoulense in Korea.

Animals↗

Intestinal mastocytosis and goblet cell hyperplasia in BALB/c and C3H mice infected with Neodiplostomum seoulense.

Mucosal mast cell (MMC) and goblet cell (GC) responses were observed in the small intestine of two strains of mice (BALB/c and C3H) infected with Neodiplostamum seoulense, and their roles in the host defense and worm expulsion were studied. From day 3 to 28 post-infection (PI) with 200 metacercariae, the worm recovery rate from BALB/c mice was consistently and remarkably higher than that from C3H mice. In the duodenum of both strains of mice, the main habitat of the flukes, mastocytosis was pronounced on day 7 PI but quickly diminished thereafter. Similar kinetics were observed in the jejunum and ileum, although the extent of mastocytosis was lesser in the ileum than other two areas. These MMC kinetics were not different between the two strains of mice. Moreover, the extent of mastocytosis was stronger in BALB/c mice than in C3H mice. GC hyperplasia was remarkable in the duodenum of BALB/c mice throughout the course of infection except day 14 PI, whereas it was recognizable only in the jejunum and ileum of C3H mice on day 7 PI. Mucin activation was evidently demonstrated in both strains of mice throughout the course of infection, but more marked in BALB/c than in C3H mice. The results strongly suggest that mastocytosis and GC hyperplasia are local immune responses against N. seoulense, however, they play a minor role in the host defense and worm expulsion.

Animals↗

Experimental verification of the metacercarial stage of Rhipidocotyle lepisostei (Trematoda: Bucephalidae) with notes on the natural occurrence of its adult stage in gars in Texas and Virginia.

Bucephalid metacercariae found encysted in the caudal fin rays of striped mullet (Mugil cephalus) were fed to bucephalid-free spotted gars (Lepisosteus oculatus) in the laboratory. Gravid specimens of Rhipidocotyle lepisostei were recovered from the intestinal tracts of 2 of 3 gars from 7 to 28 days later. Further attempts to complete the entire life cycle were unsuccessful. Natural infections of adult R. lepisostei were found in the type host, the alligator gar Lepisosteus spatula, from Galveston Bay, Texas, and in the long-nose gar, Lepisosteus osseus, from the York River, Virginia. This report confirms the identity of the metacercarial stage in the mullet as R. lepisostei and extends the known range of this parasite from the Louisiana and Texas area to the U.S. Atlantic coast.

Animals↗

Development of Fasciolopsis buski (Trematoda : Fasciolidae) in Hippeutis umbilicalis and Segmentina trochoideus (Gastropoda : Pulmonata).

Sequential development and histopathologic effects of Fasciolopsis buski larvae were examined in two species of pulmonate snail, Hippeutis umbilicalis and Segmentina trochoideus. Miracidial attachment and penetration began 5 min post-exposure (PE). On day 2 PE, the sporocysts rapidly increased in size and over days 3-7 PE, they transformed into mother rediae which migrated to the ovotestis on day 10 PE. In both species of snail, daughter rediae were initially observed on day 17 PE, the first cercariae emerged on day 21 PE, and from that day onward daughter rediae were the dominant larval form occupying the ovotestis. Histopathologic changes were confined exclusively to the ovotestis and included lytic lesions due to mechanical damage, and disappearance of all cellular elements. No inflammatory responses were observed in the ovotestis, and no degenerated larvae of any kind were observed in the snails. Infected snails did not produce egg masses and lived no longer than 35 days. The lack of differences in miracidial recognition and penetration, and in the temporal, sequential, and spatial development of F. buski larvae in H. umbilicalis and S. trochoideus indicate that both these snail species are equally susceptible to F. buski.

Animals↗

Susceptibility of inbred mouse strains to infection with three species of Metagonimus prevalent in the Republic of Korea.

Susceptibility of inbred mouse strains to Metagonimus yokogawai, Metagonimus miyatai, and Metagonimus takahashii infections was studied using BALB/c, ddY, C57BL/6J, C3H/HeN, and A/J mice, with H-2 haplotypes d, s, b, k, and a, respectively. Two hundred metacercariae were orally fed to each mouse, and the worm recovery rates (WRR), worm dimensions, and intrauterine egg numbers were measured at days 3, 7, 14, 21, and 28 postinfection (PI). On day 14 PI, the WRR of M. yokogawai was highest in ddY mice (average, 62.2%); those of M. miyatai and M. takahashii were highest in ddY (19.5%) and BALB/c mice (10.4%), respectively; worm maturation was best in C3H/HeN (M. yokogawai), C57BL/6J (M. miyatai), and ddY mice (M. takahashii). All mouse strains showed higher susceptibility to infection with M. yokogawai than with M. miyatai or M. takahashii. The results show that susceptibility of mice to Metagonimus infection varies according to mouse strain and parasite species but is suggested to be independent of the mouse H-2 haplotype.

Animals↗