Nationwide survey of human parasite in China.

A nationwide survey of human parasites in China was conducted during 1988-1992, with a coverage of 30 provinces/autonomous regions/municipalities (P/A/M). A total of 2,848 pilot sites in 726 counties were selected by random sampling, and 1,477,742 individuals residing on were surveyed by fecal examination. The status of paragonimiasis, hydatid diseases, cysticercosis and trichinellosis were summarized through data review. The overall infection rate of intestinal parasites was 62.6% whereas at provincial level, the highest infection rate (94.7%) was recovered in Hainan, and the lowest (17.5%) in Heilong-jiang. A high proportion (43.3%) of polyparasitism among the infected population (882,080) was revealed. Altogether 56 species of parasites comprising protozoa (19), trematode (16), cestodes (8), nematodes (12) and thorny-headed worm (1) were discovered. During the survey a new species and several new records were documented. The number of the population infected with common intestinal parasites was estimated. The diversities of parasite distribution were noted in different nationalities as well as in varied occupations.

[Comparative studies on the diagnosis of clonorchiasis by IEST and IFAT].

Both immunoenzymatic staining technique (IEST) and indirect fluorescent antibody test. (IFAT) with frozen sections of adult Clonorchis sinensis as antigen were employed for detecting 51 cases with clonorchiasis and 50 healthy persons. The positive rate was 92% with IEST and 88% with IFAT. The results showed no significant statistic difference (P > 0.05). The false positive rates were 2% with the former and 4% with the latter. When sera from 22 cases with acute schistosomiasis, 20 cases with chronic schistosomiasis and 15 cases with paragonimiasis were examined by IEST and IFAT, cross-reactions were 14%, 5% and 0% with IEST, and 14%, 10% and 0% with IFAT, respectively. The results showed that both IEST and IFAT are useful methods for serological diagnosis of clonorchiasis and the antigen on the gut was well demonstrated, while IEST might be more suitable in field surveys.

[Efficacy of pyquiton in the treatment of Echinochasmus liliputanus infection].

Two hundred cases of Echinochasmus liliputanus infection were randomly divided into three groups and treated with pyquiton at a single dose of 10.5 and 2.5 mg/kg, respectively. As assessed one month after treatment the egg negativity rates were 100%, 98.7% and 96.5%, respectively. The symptoms such as abdominal pain, distension, diarrhea and anorexia relieved. The results suggest that pyquiton is effective against Echinochasmus liliputanus infection.

Liver ultrasound findings in a low prevalence area of S. japonicum in China: comparison with history, physical examination, parasitological and serological results.

The paper describes a study carried out in a community in Dongdian township, Anhui Province, People's Republic of China. Medical history and the results of a physical examination, ultrasound investigation, parasitological and serological tests for Schistosoma japonicum infection were compared in 661 persons of 169 households. A lack of correlation between parasitological and serological indicators of infection and morbidity was observed in this area of low (6.4%) prevalence and intensity of infection. The prevalence of abnormal ultrasound findings in the liver in this population was high (56%), and was significantly higher than the prevalence of S. japonicum infection. The abnormal ultrasound findings correlated with a history of schistosomiasis, and the correlation increased significantly according to the number of times treated and the time since the last treatment, which suggested that past parenteral treatment has a role in the high rate of abnormal liver ultrasound findings. The significant correlation between the qualitative and quantitative serological results and abnormal ultrasound parenchymal patterns suggests that cross-reactivity between the etiology of the parenchymal disease and these tests is occurring. The presence of HBsAg correlated with the composite presence of ultrasound abnormalities of the liver parenchyma: increased echogenicity, periportal fibrosis and/or nodules and irregular fibrosis, whereas a normal ultrasound pattern was associated with the absence of HBV antigenemia.

Ultrastructure of ultraviolet radiation-induced hairless mouse skin carcinogenesis, with special reference to the epidermal-dermal junction.

The ultrastructure of ultraviolet (UV)-induced skin pathology was studied in mice to complement previously reported gross and light microscopic findings, and to assess further the usefulness of the animal model for study of sunlight associated epidermal tumours in man. Hairless albino (HRA/Skh-1) mice were exposed to a minimal erythemal dose from a filtered light source emitting both UVA and UVB, approximating solar emission. Samples of normal and hyperplastic skin, pedunculated papillomas, carcinomas in situ and invasive squamous cell carcinomas were processed for transmission electron microscopy once their identity was confirmed by light microscopic examination. Keratinocyte pleomorphism became more marked and cell to cell contact diminished as malignancy developed. For papillomas, carcinomas in situ and invasive squamous cell carcinomas, there was a progressive disruption of the epidermal junction which became marked upon frank invasion. Most of the differences between the various categories of pathological change, therefore, were not absolute but rather of degree, supporting the notion that invasive squamous cell carcinoma represents an end stage for malignancy which may arise de novo, directly from hyperplastic skin, or proceed from other tumour types. The similarity in structure of the mouse tumours to comparable tumours in man supports the usefulness of the animal model and suggests that the results have implications for sunlight associated tumours in man.