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.

An attempt to study the economic loss arising from Schistosoma japonicum infection and the benefits derived from treatment.

From the northern and southern portions of Leyte Province, which are endemic for schistosomiasis, a total of 801 infected individuals were interviewed, examined, and classified into mild, moderate, severe and very severe forms of disease with an assumed loss of working capacity for each category. The frequency rate or number of spells of illness for the past year under observation were correlated with the degree of incapacity to get the total days lost per person per year. Following a series of computations, of which the disability rate was considered as the most important, a total of 45.4 days lost per infected person per year was arrived at. Treatment of the disease with praziquantel was carried out and the patients were followed up one year after treatment, at which time the same methodology was applied. The results show that the 45.4 days lost prior to treatment went down to 4 days lost. There was an economic gain of 41.4 days as a result of treatment. This can be expressed in terms of financial value if we consider half of the infected cases as breadwinners receiving a minimum wage. It should be noted that a number of assumptions in this study were made. It is, however, hoped that this work will serve as a guide and a starting point for others to carry out related studies on economic loss and subsequent economic benefits to justify budgetary requests/allocations for the implementation of various preventive and control measures.

Schistosoma japonicum in the pig: the influence of age on the host/parasite relationship.

The current study sought to elucidate a possible association between age and susceptibility to a primary infection with Schistosoma japonicum in pigs. Sixteen Landrace/Yorkshire crossbred specific pathogen-free pigs in three different age groups (group A-C), aged approximately 7, 24 and 37 weeks at the beginning of the experiment, were infected by intramuscular injections of 1,000, 1,500 or 2,400 cercariae, respectively. Fecal egg counts were obtained twice weekly from six to eight weeks post infection (wpi), and the pigs were killed 11 wpi. The number of worms collected were counted and sexed subsequent to perfusion. Tissue egg counts were estimated on samples from the liver. The worm recoveries for group A, B and C were 3.2%, 8.1% and 3.8%, respectively. No differences were observed between the male/female ratios of the three groups. The fecundity parameters, ie, fecal egg counts per mature female and liver egg counts per mature female, showed no significant differences between the three age groups. The results did not indicate any difference in susceptibility between the different age-groups of pigs to a primary infection with S. japonicum.

Comparative studies on detecting CAg in urine of acute schistosomiasis patients by mAb-RIHA and mAb-DotELISA.

Urine was concentrated 20-fold for assay for CAg of Schistosoma japonicum. mAb-RIHA and mAb-DotELISA were positive in 78, 31% and 65.06% of cases respectively, of 83 patients with acute schistosomiasis. The false positive rates in 101 healthy controls were 14.85% and 0%, respectively. Cross-reactions (using mAb-RIHA) were seen in 16.36% and 14.28% of patients with clonorchiasis, 49 patients with ankylostomiasis, respectively. Corresponding figures for mAb-DotELISA were 0% and 0%.

Impact mass chemotherapy with praziquantel on schistosomiasis control in Fanhu village, People's Republic of China.

The paper describes the endemic situation of schistosomiasis japonica in Fanhu village, Poyang Lake region, China and the effect of the strategy of combining annual mass chemotherapy with health education on schistosomiasis control in the community. The results showed that the prevalence of infection with schistosome reduced form 26.0% in 1992 to 10.7% in 1994, the intensity of infection in residents decreased from 1.92 in 1992 to 0.55 in 1994 and the condition of hepatomegaly, splenomegaly and liver fibrosis also improved after chemotherapy in the individuals in the case prospective study. Moreover, the future strategies of schistosomiasis control in this area have been suggested according to the transmission of schistosomiasis in the lake region and the effect of anti-schistosomiasis control indifferent populations.

The effect of a combined approach to schistosomiasis control on the transmission of Schistosoma japonicum in Xingzi of Poyang Lake area, China.

The impact of a combined approach to schistosomiasis control from 1987 to 1989 and mass chemotherapy from 1992 to 1994 was studied in a rural community in Xingzi county in the northwest corner of Poyang Lake in Jiangxi Province, China. Humans, cattle, buffalo and pigs were known potential reservoirs of Schistosoma japonicum. Transmission occurs during water contact on and around seasonally flooded marshes that are used for grazing, the harvesting of grass and fishing. Humans and livestock underwent yearly selective mass chemotherapy, and snails were eliminated through ploughing and compacting of the marshland in the spring of 1988. Transmission was monitored through the determination of annual re-infection rates in samples of the human population, the annual examination of piles of feces from animals and humans in the marshland, the annual collection and examination of intermediate snail hosts, and the exposure to potentially polluted water and subsequent examination of sentinel mice. Schistosomiasis prevalence among humans and animals declined sharply as soon as mass chemotherapy was implemented. Snail density decreased even before mollusc control was started, possibly indicating a high variability of this indicator. The infection rates of snails and sentinel mice reached zero after a single application of mollusc control. The results underline the importance of single infected water buffalo for the transmission of schistosomiasis. Since the impact stopped for two years (1990-1991), the schistosomiasis prevalence rose quickly. Mass chemotherapy was an effective means to curb the prevalence of schistosomiasis in this area, but the effects were only maintained for one or two years in the marsh zone.

Reinfection with Schistosoma japonicum after treatment with praziquantel in Poyang lake region, China.

The study on reinfection with Schistosoma japonicum after treatment was carried out in a cohort of subjects in a heavy endemic village of Poyang lake region, China. After mass treatment with praziquantel in non-transmission time, detailed observations of water contact were estimated using the mean area of skin exposed daily. One year after treatment, the prevalence of infection in study subjects was 54.48%, returning to 83% of initial prevalence. The peak prevalence occurred the 11-15 year age class, but intensity of exposure also varies with age and that age group supporting the higher prevalence of reinfection had high levels of exposure. Among groups of subjects with a similar exposure stratum, young subjects under the age of 21 years were more heavily reinfected, while no heavy reinfection was observed in adults (> or = 25 years). These observations suggest that subjects in this area slowly acquire an increasing degree of immunity to lighten the intensity of infection with S. japonicum.

Studies on chemotherapy of parasitic helminths: efficacy of artemether on Japanese strain of Schistosoma japonicum in mice.

Effects of artemether were examined on Schistosoma japonicum in mice. When the drug was given at a daily dosage of 200 mg/kg for 4 successive days from 46 days post-infection, a significant reduction in worm recovery was observed. A significant reduction in size of worms from the medicated mice was also seen compared with that from non-medicated controls.

Sensitivity of different isolates of Schistosoma japonicum from China to praziquantel.

Groups of C57BL inbred mice infected with each of the 4 different isolates, (Anhui, Hubei, Sichuan and Yunnan) of Schistosoma japonicum from the mainland of China were treated with praziquantel (PZQ) and the parasiticidal effects were compared. Worm reduction rate was recorded to assess systematically the sensitivity of 4 different isolates to PZQ in the mouse. Three dosage-levels of PZQ, ie 150, 230 and 310 mg/kg body weight in single doses were used. The worm development rates of control groups infected with schistosomes from Anhui, Hubei, Sichuan and Yunnan were 75.5, 81.8, 81.5, and 83.0%, respectively. At the dosage-level of 150 mg/kg, the worm reduction rates for the 4 different isolates were 36.0, 33.9, 25.5 and 35.6%, respectively. At the dosage-level of 230 mg/kg, the rates were 47.1, 46.0, 38.1 and 47.7%, while at the dosage-level of 310 mg/kg, they were 59.3, 58.6, 50.8 and 61.7%, respectively. The results indicated that the worm reduction rate of the Sichuan isolate was lower than that of the other three isolates, however, the differences were not statistically significant, suggesting that schistosomes of Anhui, Hubei, Sichuan and Yunnan isolates bear resemblance in drug response.

Dose finding double-blind clinical trial with praziquantel in schistosomiasis japonica patients.

A double-blind clinical trial with praziquantel was carried out. A total of 400 cases was treated with four different dosages, namely, 60, 50, 40 and 30 mg/kg body weight of praziquantel. The drug was given in one day divided into two doses. Identical placebo tablets were used to make up a total of 60 mg/kg. Tolerance was good in all with the exception of one case suffering from asthmatic attack with papule rashes over large area of the body surface. 394 patients were able to be followed up parasitologically six months post-treatment. 79.8%, 71.7%, 78.8% and 70.1% of the patients were negative in the groups with the total dose of 60, 50, 40 and 30 mg/kg respectively. The cure rates as well as the side effects were similar for the four groups. The efficacy was lower than that reported by other authors and the possibility of reinfection was incriminated. In villages with few snails the negative hatching rates in aforementioned four groups were 89.1%, 91.1%, 88.9% and 81.8%, while in villages with abundant snails the rates were 68.2%, 46.5%, 66.7% and 54.8%. The difference between the two areas was statistically significant. Higher efficacy was observed in adults with an average cure rate of 80.0% than in children under 15 years of age, the average cure rate being 57.1%.(ABSTRACT TRUNCATED AT 250 WORDS)