Antibodies in serum of patients with clonorchiasis before and after treatment.

Sera of 31 patients infected with Clonorchis sinensis were examined using fraction 1 antigen by ELISA during a one-year observation. The results of ELISA with Igs, IgG and IgA demonstrated high sensitivity (100%, 100% and 90%) and specificity (100%, 100% and 87%). Sera specific Igs and IgG were significantly decreased in the 3rd month after treatment with praziquantel (25mg/kg body weight in one dose), and IgA was significantly decreased in the 1st month (paired t-test, p < 0.05). No eggs were found in the stool after treatment. Detection of sera specific Igs, IgG and IgA by ELISA was combined with stool examination to evaluate the effect of praziquantel and the completeness of the cure.

Clinical studies on angiostrongyliasis cantonensis among children in Taiwan.

Angiostrongyliasis cantonensis is a disease commonly seen in Taiwan, especially in children during the summer rainy season. Most of the cases reported in other countries were adults and their clinical manifestations were different from children. Studies on special clinical characteristics of angiostrongyliasis cantonensis among 82 children in Taiwan were performed. Thirty-eight (46.3%) were male and 44 (53.7%) females, and 87% could be traced to a history of contact with the intermediate host, the giant African snail, Achatina fulica, which plays a major role in transmission. The incubation period (average: 13.2 days) was shorter in children than in adults (average: 16.5 days). In about one-third (30.5%) of the total cases, the clinical form was meningoencephalitis, which was higher than in adult cases seen in Thailand (5%). The most common clinical symptom was fever (91.5%), followed by vomiting and headache. The percentages of sixth and seventh cranial neuropathy associated with the disease were 19.5% and 11.0% respectively. Ophthalmologic fundoscopy showed that 25.0% with papilledema which was significantly higher than seen in adults (12%) in Thailand. Most of the cases in this study had peripheral leukocytosis (above 10,000/mm3) and eosinophilia (above 10%); the percentages were 82.9% and 84.1%, respectively. The worm recovery rate from cerebrospinal fluid by lumbar puncture of 82 cases was 41.5%; 141 worms were collected from one female patient using a pumping method. In the recent 2 years, albendazole and levamisole were used clinically with good result.

Clonorchiasis in Taiwan.

Since Ohi in 1915 found clonorchiasis patients in Taiwan, many surveys have shown that Miao-li in the north, Sun-moon Lake in the middle and Mei-nung in the south of Taiwan are three important endemic areas of clonorchiasis. In recent studies, the disease showed a tendency to extend its endemicity. Rats, cats, dogs and pigs are the natural reservoir hosts, and 17 species of fresh water fish are also infected with metacercaria. One definitive snail host, Parafossarulus manchouricus, and two other suggested snails, Semisulcospira libertina and Thiara granifera, may serve as the first intermediate host. The human incidence is about 20-50% in endemic areas and 10-20% in newly infected localities. Higher infection rates and more intensities of the worm burden are observed in the adult males. A higher incidence is also observed in the Hakkanense ethnic group. The infection according to the occupation has changed from merchants and government employees to farmers. Praziquantel, 60 mg/kg body weight divided into three doses by oral route in one day, has been given to 356 patients and revealed a 96% cure rate and a 99% egg reduction rate. This regimen is highly recommended for the treatment of clonorchiasis.

Current status of food-borne parasitic zoonoses in Taiwan.

More than 50 species of zoonotic parasites (nematodes-18 spp., trematodes-19 spp., cestodes-10 spp., protozoa-2 spp., and arthropods-2 spp.) have been reported in Taiwan. Among them, Angiostrongylus cantonensis, Clonorchis sinensis and Taenia saginata are the most important and most common food-borne parasites. Angiostrongyliasis is highly endemic in southern and eastern Taiwan. About 80% of patients are children below 15 years of age, mostly infected after eating Achatina fulica during May and September. Patients residing in the mountainous and remote areas are more susceptible than those in the urban districts. Cipangopaludina chinensis and Ampullarium canaliculatus are additional important sources of infection. Albendazole is effective in treating infections in animals. Levamisole has been shown to shorten and lighten the course and symptoms in clinical trials. Clonorchiasis is endemic in Miao-li in northern, Sun-moon lake in central, and Mei-nung in southern Taiwan. Recent surveys, however, have shown endemic areas to be more extensive. Hakkanese and farmers have a greater tendency of infection than other groups. Praziquantel, 3 doses of 20 mg/kg body weight for one day, is an effective treatment. Taeniasis saginata is mainly caused by eating raw beef or viscera of wild animals by the aborigines. A single dose of 150 mg praziquantel cures almost 100%.

Counterimmunoelectrophoresis test on human Clonorchis sinensis infection.

A counterimmunoelectrophoresis test was used to detect antibodies against the adult worm antigen of Clonorchis sinensis in sera from 70 clonorchiasis patients, 20 uninfected healthy persons and 7 patients infected with other helminths. A constant voltage of 10 V/cm and a running time of 30 minutes was chosen in carrying out detection. Antibody titers of 1, 1:2 and 1:4 were obtained from 35, 21 and 14 clonorchiasis patients, respectively. Significant correlation was observed between worm burden in patients and antibody titer, the higher the antibody titer in patients, the more eggs per gram feces in their stool. Although cross reaction was observed with toxocariasis and angiostrongyliasis in this study, high (100%) sensitivity made it possible to screen the subjects in endemic areas to shorten the survey period.

Preparation of monoclonal antibody against Angiostrongylus cantonensis antigen.

Monoclonal antibodies (MAb) against A cantonensis were produced through fusion of immunised spleen cells from BALB/c mice with NS-1 myeloma cells at a ratio of 10:1. The successful fusion rate on the 3rd day of fusion was 90.1%. Ten MAb were characterised, six of which were IgG1 and the remaining four were IgG2a, IgG2b, IgM and IgA respectively. Among 6 IgG1 MAb, four were A. cantonensis-specific, of which three reacted to adult worm antigen only and one reacted to both adult worm and juvenile worm antigens. Two other IgG1 MAb showed cross-reaction with other helminthic antigens of Toxocara canis. Ascaris suum. Paragonimus westermani, Dirofilaria immitis, Anisakis Spp, Gnatostoma Spinigerum and Clonorchis sinensis.