Hidatidosis en china

Am. J. Trop. Med. Hyg., 66(1), 2002, pp. 23–29 2002 by The American Society of Tropical Medicine and Hygiene Copyright

COMBINED ULTRASOUND AND SEROLOGIC SCREENING FOR HEPATIC ALVEOLAR ECHINOCOCCOSIS IN CENTRAL CHINA
BRIGITTE BARTHOLOMOT, DOMINIQUE A. VUITTON, SAID HARRAGA, DA ZHONG SHI, PATRICK GIRAUDOUX, GUY BARNISH, YUN HAI WANG, CALUM N. L. MACPHERSON, AND PHILIP S. CRAIG WHO CollaboratingCentre for Prevention and Treatment of Echinococcosis, University of Franche-Comte, Besancon, France; ´ ¸ Lanzhou Medical College, Lanzhou, Gansu, PR China; Liverpool School of Tropical Medicine, Liverpool, United Kingdom; Xinjiang Medical University, Urumqi, Xinjiang, PR China; Winward Islands Research and Education Foundation, St. George’s University, Grenada, West Indies; Department ofBiological Sciences, Salford University, Salford, United Kingdom

Abstract. Alveolar echinococcosis (AE), caused by Echinococcus multilocularis, is a zoonotic helminthic disease that can mimic malignancy. In the 1970s, foci of the disease were found in central China. The aim of the present study was to estimate the prevalence of AE in humans in 2 districts of south Gansu Province, China, by use ofultrasound and Echinococcus serology. After answering an epidemiological questionnaire, 2,482 volunteers from 28 villages underwent ultrasound. Serology via enzyme-linked immunosorbent assay for antibody activity was performed on whole blood collected on filter paper in all subjects; on serum from subjects with an abnormal ultrasound image; and on randomly chosen subjects that either had no lesions orhad atypical lesions. At least one (25.3%) abnormal ultrasound image was observed in 630 of the subjects screened. A typical lesion of progressive AE was found in 84 subjects (3.4%). Serologies were positive in 77 (96%) of 80 of patients who had lesions typical of progressive AE. Ultrasound is useful for screening for AE in endemic regions. INTRODUCTION Alveolar echinococcosis (AE) is a relativelyrare zoonotic helminthic disease that can mimic malignancy. It is caused by the development of the larval form of the canine tapeworm Echinococcus multilocularis in the liver. Invasion of surrounding organs, vessels, or both and distant metastases can result in obstruction of bile ducts and hepatic vessels. The disease can be severe and can lead to death within 5– 10 years unless treated.1,2Progress in surgical management of the disease and the use of albendazole and mebendazole at high dosages have improved the prognosis of AE.3 Early detection and treatment of AE has been shown to significantly improve survival.4,5 Even though the odds of asymptomatic AE lesions progressing to severe disease are not known, it is reasonable to hypothesize that population-based screening is justified toidentify asymptomatic forms of the disease in endemic countries. Areas endemic for AE include the central part of western Europe, parts of the Near East, Russia, and central Asian Republics, northern Japan, and Alaska.1,2 A focus of high prevalence of the disease in central China was suggested in the early 1970s by examination of hospital records from Gansu, Ningxia, Qinghai, and Sichuan Provinces.The high prevalence of AE in these provinces was confirmed in the 1990s by a pilot screening program that used a combination of serologic testing and ultrasound examination.6 A more systematic screening program was undertaken in 1994–1997 in 2 districts of south Gansu Province (Zhang and Puma counties) for the following reasons: (1) to evaluate the limits of the endemic area in south Gansu; (2) toestimate the prevalence of E. multilocularis infection in this area; (3) to evaluate the feasibility and diagnostic value of the association of ultrasonography with serology for the screening of AE in rural communities, which are distant from any medical center or hospital; and (4) to identify the risk factors and transmission patterns that could be involved both in the presence of this...