Molecular detection of Schistosoma japonicum in infected snails and mouse faeces using a real-time PCR assay with FRET hybridisation probes

A real-time polymerase chain reaction (PCR) assay with fluorescence resonance energy transfer (FRET) hybridisation probes combined with melting curve analysis was developed to detect Schistosoma japonicum in experimentally infected snails and in faecal samples of infected mice. This procedure is based on melting curve analysis of a hybrid between an amplicon from the S. japonicum internal transcribed spacer region 2 sequence, which is a 192-bp S. japonicum-specific sequence, and fluorophore-labelled specific probes. Real-time FRET PCR could detect as little as a single cercaria artificially introduced into a pool of 10 non-infected snails and a single egg inoculated in 100 mg of non-infected mouse faeces. All S. japonicum-infected snails and all faecal samples from infected mice were positive. Non-infected snails, non-infected mouse faeces and genomic DNA from other parasites were negative. This assay is rapid and has potential for epidemiological S. japonicum surveys in snails, intermediate hosts and faecal samples of final hosts.

Anthelmintic effect of artesunate in experimental heterophyid infection

Artesunate is a water-soluble semi-synthetic drug derived from artemisinin which is extracted from leaves of the Chinese plant Artemisia annua. This successful bas-ically-antimalarial drug has been proved to be also effective against trematodes like Schistosoma japonicum, S. mansoni, Fasciola hepatica and Clonorchis sinensis, The present work aimed to investigate the in-vivo efficacy of artesunate against heterophyids in mice, using praziquantel as a therapeutic control. Results showed that artesunate was effective in treatment of experimental heterophyidiasis as proved by a 100% reduction of intestinal adult worm count at a dose regimen of 200 mg/kg/day, given for 3 successive days. Besides, surface tegumental damage of the adult worm was observed by SEM in form of bleb formation, disruption, erosion and peeling. The proved therapeutic efficacy of artesunate together with its reported safety, favor its possible use as a new alternative therapy in human heterophyidiasis

Cerebellar Schistosomiasis: A Case Report with Clinical Analysis

The authors report here a rare case of cerebellar schistosomiasis identified by pathological diagnosis, lacking extracranial involvement. The clinical symptoms included headache, dizziness, and nausea. Studies in blood were normal and no parasite eggs were detected in stool. Computed tomography of brains showed hypodense signal, and magnetic resonance imaging showed isointense signal on T1-weighted images, hyperintense signal on T2-weighted images, and intensely enhancing nodules in the right cerebellum after intravenous administration of gadolinium. A high-grade glioma was suspected, and an operation was performed. The pathologic examination of the biopsy specimen revealed schistosomal granulomas scattered within the parenchyma of the cerebellum. The definitive diagnosis was cerebellar schistosomiasis japonica. A standard use of praziquantel and corticosteroid drugs was applied, and the prognosis was good. When the pattern of imaging examinations is present as mentioned above, a diagnosis of brain schistosomiasis should be considered.

Novel real-time PCr for detection of Schistosoma japonicum in stool.

Chemotherapy has been used on a large scale in countries where the blood fluke Schistosoma japonicum is endemic. This has led to a lower intensity of infections and consequently lower diagnostic values of commonly used diagnostic tests like serology and Kato-Katz stool smear. We designed a novel real-time PCR method for detection of S. japonicum in stool samples. Further, we evaluated different versions of an inexpensive, non-commercial extraction method, ROSE, as well as the commercial QIAamp DNA Stool Mini Kit. PCR primer sequences were designed targeting the mitochondrial NADH dehydrogenase I gene. Bovine serum albumin was added to the DNA extracts and SYBR Green was used for detection. The PCR method was evaluated with non-infected stool samples spiked with S. japonicum eggs. It demonstrated high sensitivity, even in samples containing a single egg. The two extraction methods were equally effective. The PCR was specific for S. japonicum when tested against other Schistosoma species, Trichuris trichiura, hookworm and Taenia sp. We conclude that this novel real-time PCR, in combination with either ROSE or QIAamp DNA Stool Mini Kit extraction, is a sensitive and specific tool for diagnosing S. japonicum in human stool samples.

Vertical transmission of Schistosoma japonicum in the rabbit / 华中科技大学学报（医学）（英德文版）

The aim of the present study was to confirm observations on the vertical transmission of Schistosoma japonicum in the rabbit. S. japonicum-infected pregnant rabbits were used in this study. Perfusion of mother rabbits was done 9 weeks after infection in order to obtain worm burdens in relation to their initial cercarial dose. Anti-schistosoma specific IgM antibodies in serum samples collected from rabbit kittens were detected by ELISA. Our results showed that gestation period lasted the normal 29-31 days. All the exposed mother rabbits became infected with S. japonicum. Positive IgM antibody OD values were detected in 12 out of the 60 kittens examined (20.0%). In group C and A, 40.0% and 17.9% of the kitten were congenitally infected, respectively. 18.1% of the kittens born to mothers infected with a single dose of 200 cercariae per rabbit were positives; this is not significantly different from that obtained for the 600 dose group (22.2%). Three randomly selected IgM+ kittens harbored between one and two adult worms. The livers of these kittens displayed granulomatous lesions. It is concluded that congenital S. japonicum infection does occur in the rabbit and is affected by the mother stage of pregnancy and to a lesser extent by its infection load.

An epidemiological investigation of congenital Schistosoma japonicum transmission in Hubei Province, PR China.

A cohort study was conducted in Hubei Province, China, following serious flooding of the Yangtze River in the autumn of 1998 to investigate the possibility of congenital transmission of Schistosoma japonicum in humans. The cohort investigated was comprised of 205 women and their 208 infants born between 1 September and 30 December 1998. Blood and fecal samples from all the women and their infants were collected and examined for S. japonicum infection. Positive specific antibody titers were found in 14 (6.8%) of the mothers, but no fecal egg excretion was observed. All infants had negative specific antibody titers and no S. japonicum eggs were found in their feces. Hence, the present study coud not confirm congenital S. japonicum transmission in humans. Further studies are highly wanted to study the impact of prenatal exposure of S. japonicum on the offspring.

The role of health education for schistosomiasis control in heavy endemic area of Poyang Lake region, People's Republic of China.

For exploring the impact of health education for schistosomiasis control in a heavy endemic area of Poyang Lake region, China, the residents residing in the heavy endemic area were divide into three kinds of target population: pupils, adult women and adult men, and then targeted health education was implemented respectively among the three kinds of population after a baseline survey. The result were compared with that in the control group. The anti-schistosomiasis knowledge level among the three kinds of population improved significantly, the correct rate of attitude to examination and chemotherapy among pupils and adult men and the correct rate of anti-schistosomiasis value concept among women were raised greatly, obedience to examination and chemotherapy among adult men increased, the rate of infested water exposure and infection rate among pupils and adult women declined remarkably. Therefore, infection with Schistosoma japonicum (Sj) can be controlled effectively among women, especially pupils and obedience to examination and chemotherapy among adults men can be improved by implementing health education.

Parasitological and histopathological studies on rhesus monkeys infected with Chinese mainland strain of Schistosoma japonicum.

Fifteen rhesus monkeys were infected by cutaneous exposure each with 200 or 300 cercariae of Schistosoma japonicum. The dynamic distribution of schistosomula in the skin showed that 77-90% of them were found in the connective tissue, while 10-23% migrated in the hair follicles and sebaceous glands at different time intervals after cercarial penetration. Dead schistosomula recovered from the skin varied from 8.7% to 28.7%. The average rate of adult worm recovery was 74.4% and 61.3% in the 6th and 15th weeks of infection, thereafter the rate decreased to 32.3% and 9.0% in the 19th and 42nd weeks, respectively. The mean length of mature pair-worms was 13.2 +/- 2.3 mm in male and 18.0 +/- 1.9 mm in female 6 weeks of worm age. Afterwards the body length of females and their sexual gland diminished markedly. The mean prepatent period was 35.0 +/- 0.6 days. The average size of mature eggs in the feces was 86.6 +/- 5.4 x 64.3 +/- 3.6 microns, and the peak of eggs passage in the feces occurred between 7th and 15th weeks after infection, later on the number of eggs markedly decreased. Skin reaction to the primary infection was slight. The pathological changes observed in liver were chiefly cellular infiltration of portal spaces and the lesions produced by egg granulomas. The mean volume of single-egg granulomas of the productive stage in liver was 22.7 +/- 10.5 mm3 x 10(-3). The most intensive damages in the gastro-intestinal tract were observed in the large intestine.(ABSTRACT TRUNCATED AT 250 WORDS)

Schistosoma japonicum-like infection in Phichit province, northern Thailand: a case report.

A case of human schistosomiasis from Phichit Province is presented. Schistosome eggs were found in the ileo-caecal mass of a 44-year old woman, native of Sak-Lek, Muang District. Histologic pictures revealed an early acute granulomatous lesion which consisted of predominantly eosinophils without multinucleated giant cells and fibrotic change suggesting a recent infection. On the basis of the shape and microscopic appearance of the eggs, they are smaller than those described previously for Schistosoma japonicum, probably those of S. mekongi, a related species. This is the third histologic-confirmed case of schistosomiasis in this locality. Addendum: At the time of the manuscript preparation, another case of schistosomiasis was diagnosed. A 55-year old man who lives entirely in the very close adjacent village to the present case was admitted to the Ramathibodi Hospital, Bangkok with chronic hepatosplenomegaly in January 1986. Amyloidosis was suspected and rectal biopsy revealed schistosome eggs, some contained miracidia with varying degrees of degeneration, some were empty and/or fragmented shells and were surrounded with fibrotic changes and chronic cellular infiltration (Fig. 5). They were identical to those of Schistosoma japonicum. Several fecal examinations, miracidium hatching and COPT yielded negative results. This finding showed significantly that all schistosomiasis cases reported from this locality, except the second one, were in the old age group of 40 and above. Further epidemiologic investigation is in progress to delineate this locality as a potential endemic area for this infection.

Attempts to standardize the circumoval precipitin test (copt) for Schistosomiasis japonica.

The circumoval precipition test (COPT) is a simple and inexpensive immunodiagnostic test for schistosomiasis japonica which, in the Philippines, has high sensitivity and specificity. Lack of standardization does, however, increase the variability of the test. Parameters which influence the COPT have been examined using large numbers of sera from known S. japonicum infected individuals. In this series of experiments, optimal conditions were determined to be as follows using 2 drops of neat serum and incubation at 37 degrees C in a sealed slide chamber; - approximately 100 eggs from 55 or 60 days infected rabbits for a 24 to 48 hour incubation period. COP reactions (i.e. precipitates associated with eggs) were much less obvious when either immature eggs or eggs obtained from long-term infected rabbits were used. The results emphasize the prime importance of the source of Schistosoma japonicum eggs in the performance of a standardized COPT.