A large focus of alveolar echinococcosis in central China.
TL;DR: The high prevalence of human AE in this region of central China is most probably due to semi-domestic transmission of E multilocularis between wild rodents and dogs, together with the poverty and poor hygiene in these rural communities.
About: This article is published in The Lancet.The article was published on 1992-10-03. It has received 162 citations till now. The article focuses on the topics: Echinococcus multilocularis & Echinococcus.
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TL;DR: This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.
Abstract: Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.
601 citations
Cites background from "A large focus of alveolar echinococ..."
...In 1992 a large foci of human AE in central China was published (Craig et al., 1992)....
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...…by diagnostic imaging) Region AE cases Population size studied References Gansu 84 2482 Bartholomot et al. (2002) Gansu (Zhang County) 65 1312 Craig et al. (1992) Gansu (Minle County) 1a 362 Han et al. (2015) Ningxia (Xija, Guyuan and Haiyuan Counties) 96 4778 Yang et al. (2007) Ninxia (Xija…...
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TL;DR: The global burden of AE is comparable to several diseases in the neglected tropical disease cluster and is likely to be one of the most important diseases in certain communities in rural China on the Tibetan plateau.
Abstract: Background: Human alveolar echinococcosis (AE) is known to be common in certain rural communities in China whilst it is generally rare and sporadic elsewhere. The objective of this study was to provide a first estimate of the global incidence of this disease by country. The second objective was to estimate the global disease burden using age and gender stratified incidences and estimated life expectancy with the disease from previous results of survival analysis. Disability weights were suggested from previous burden studies on echinococcosis. Methodology/Principal Findings: We undertook a detailed review of published literature and data from other sources. We were unable to make a standardised systematic review as the quality of the data was highly variable from different countries and hence if we had used uniform inclusion criteria many endemic areas lacking data would not have been included. Therefore we used evidence based stochastic techniques to model uncertainty and other modelling and estimating techniques, particularly in regions where data quality was poor. We were able to make an estimate of the annual global incidence of disease and annual disease burden using standard techniques for calculation of DALYs. Our studies suggest that there are approximately 18,235 (CIs 11,900–28,200) new cases of AE per annum globally with 16,629 (91%) occurring in China and 1,606 outside China. Most of these cases are in regions where there is little treatment available and therefore will be fatal cases. Based on using disability weights for hepatic carcinoma and estimated age and gender specific incidence we were able to calculate that AE results in a median of 666,434 DALYs per annum (CIs 331,000-1.3 million). Conclusions/Significance: The global burden of AE is comparable to several diseases in the neglected tropical disease cluster and is likely to be one of the most important diseases in certain communities in rural China on the Tibetan plateau.
387 citations
Cites background from "A large focus of alveolar echinococ..."
...In Asia a major endemic focus was detected in China [6] with large numbers of human cases – in some communities 5% or more of the population is infected [7]....
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TL;DR: The behaviour of Homo sapiens has a pivotal role to play in the macro and microepidemiology of emerging or re-emerging parasitic zoonoses and clearer understanding of the heterogeneity of susceptibility to infection, the complex genetic variations of people and parasite species is shedding more light on transmission routes and the spectrum of disease that is observed.
365 citations
Cites background from "A large focus of alveolar echinococ..."
...multilocularis has been reported in domestic dogs (Stehr-Green et al., 1988; Craig et al., 1992; Schantz et al., 2003)....
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TL;DR: This work reviews existing information on transmission routes and life cycles in different geographical contexts and - where available - includes basic biological information of parasites and hosts (e.g., susceptibility of host species).
Abstract: The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.
279 citations
TL;DR: The improvement of surgical techniques, the introduction of minimally invasive treatments and more effective drugs have deeply changed life expectancy and quality of life of patients with HD.
Abstract: Echinococcosis or hydatid disease (HD) is a zoonosis caused by the larval stages of taeniid cestodes belonging to the genus Echinococcus. Hepatic echinococcosis is a life-threatening disease, mainly differentiated into alveolar and cystic forms, associated with Echinoccus multilocularis (E. multilocularis) and Echinococcus granulosus (E. granulosus) infection, respectively. Cystic echinococcosis (CE) has a worldwide distribution, while hepatic alveolar echinococcosis (AE) is endemic in the Northern hemisphere, including North America and several Asian and European countries, like France, Germany and Austria. E. granulosus young cysts are spherical, unilocular vesicles, consisting of an internal germinal layer and an outer acellular layer. Cyst expansion is associated with a host immune reaction and the subsequent development of a fibrous layer, called the pericyst; old cysts typically present internal septations and daughter cysts. E. multilocularis has a tumor-like, infiltrative behavior, which is responsible for tissue destruction and finally for liver failure. The liver is the main site of HD involvement, for both alveolar and cystic hydatidosis. HD is usually asymptomatic for a long period of time, because cyst growth is commonly slow; the most frequent symptoms are fatigue and abdominal pain. Patients may also present jaundice, hepatomegaly or anaphylaxis, due to cyst leakage or rupture. HD diagnosis is usually accomplished with the combined use of ultrasonography and immunodiagnosis; furthermore, the improvement of surgical techniques, the introduction of minimally invasive treatments [such as puncture, aspiration, injection, re-aspiration (PAIR)] and more effective drugs (such as benzoimidazoles) have deeply changed life expectancy and quality of life of patients with HD. The aim of this article is to provide an up-to-date review of biological, diagnostic, clinical and therapeutic aspects of hepatic echinococcosis.
252 citations
References
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TL;DR: Albendazole appears to be effective both for chemotherapy in inoperable cases of hydatid disease and for prophylaxis before surgery in E. multilocularis patients.
Abstract: Since 1983 data have been collected on the outcome of treatment of apparently active Echinococcus granulosus hydatid cysts with albendazole. Most patients received 800 mg albendazole daily in cycles of 28 d with 14 d between cycles, with a mean duration of 2.5 cycles (range 1-12). From an initial set of over 500 cases, 253 patients were evaluated for efficacy, with 269 hepatic, 86 pulmonary, 50 peritoneal and 51 cysts at other sites being individually assessed. 72 patients (28.5%) were regarded as cured, 129 (51%) as improved, 46 (18.1%) as unchanged and 6 (2.4%) were worse. 47 patients underwent surgery after treatment and viability was demonstrated in only 5 cysts (10.6%). Recurrence was observed in 4 of 29 non-surgical cases (13.8%) from whom a follow-up of at least 24 months was available. 35 cases of E. multilocularis infection were assessed, with cure in 2, improvements in 4, stabilization in 25 and progression in 4 cases. Side effects of treatment were uncommon. Liver function abnormalities occurred in about 20% (4% withdrawn) and there was a tendency for leucopenia to occur in E. multilocularis patients. Albendazole appears to be effective both for chemotherapy in inoperable cases of hydatid disease and for prophylaxis before surgery.
199 citations
Journal Article•
TL;DR: Attention is drawn to the urgent need for measures to prevent the importation of infected livestock and this would require the development of techniques for pre-mortem diagnosis and differentiation of hydatidosis and cysticercosis of animals.
Abstract: This review of recent literature reporting the occurrence of hydatid disease due to Echinococcus granulosus and E. multilocularis throughout the world emphasizes the global nature of the problem and the threat of its spread into those countries currently free from it. Attention is drawn to the urgent need for measures to prevent the importation of infected livestock and this would require the development of techniques for pre-mortem diagnosis and differentiation of hydatidosis and cysticercosis of animals. There must also be increased awareness of the possible occurrence of biological strains of the parasite which may be of greater or lower infectivity for man. In the absence of information on infectivity, studies concerning the prevalence of the disease may be meaningless.
190 citations
TL;DR: The first reported locally-acquired case of AHD in the conterminous United States, and the widespread occurrence and expanding range of E. multilocularis in the north-central United States and south-central Canada, point to the increasing public health importance of alveolar hydatid disease.
Abstract: The clinical features of 33 cases of alveolar hydatid disease (AHD) in Alaskan Eskimos and a review of the surgical experience with this disease are presented. Among untreated patients, progression of the disease to a fatal outcome was observed in 70%. The primary hepatic lesion resembles cancer, and errors in diagnosis by both the surgeon and pathologist are common. Although surgical resection of the entire primary hepatic lesion offers the only proven curative treatment, only 26% of those explored were resectable. All seven patients resected for cure are alive 6-27 years post-operatively (average survival, 14.7 years). A 5-year experience with continuous mebendazole therapy in the management of five nonresectable cases of AHD indicates that a favorable effect of this drug is being observed. It now appears that Echinococcus infections are no longer the sole province of the surgeon. Although the role of medical therapy is not yet clearly defined, it must be considered in the management of all cases of AHD. The first reported locally-acquired case of AHD in the conterminous United States, and the widespread occurrence and expanding range of E. multilocularis in the north-central United States and south-central Canada, point to the increasing public health importance of alveolar hydatid disease.
137 citations
TL;DR: Nomads in Turkana, a remote area of north-west Kenya, were screened for hydatid cysts by a portable ultrasound scanner and by serology, finding ultrasonography gave immediate results and provided important clinical information about the cysts.
125 citations
TL;DR: A total of 24 cases of hepatic alveolar echinococcosis (HAE) due to Echinococcus multilocularis was assessed by US and CT, confirming the diagnosis in all cases by immunologic and histologic study.
Abstract: A total of 24 cases of hepatic alveolar echinococcosis (HAE) due to Echinococcus multilocularis was assessed by US and CT. The diagnosis was confirmed in all cases by immunologic and histologic study. Both US and CT patterns of HAE showed changes of liver morphology in both contour and size. Abnormal areas of parenchyma were nodular or in fields, irregular, heterogeneous, and basically echogenic. On CT these lesions were hypodense (30 to 40 HU) and did not show enhancement after administration of intravenous contrast medium. Clustered microcalcifications were encountered within the abnormal parenchymal fields in 50% of cases, and necrotized zones occurred in 40% of cases. Dilatation of intrahepatic bile ducts was commonly seen, especially on US; hilar involvement was frequent. Follow-up by both techniques can display increases of primary lesions, occurrence of new foci, and local or regional extensions. Precise evaluation of the lesions arising from correlative use of US and CT permits adequate therapeutic management.
116 citations