Robert L. Rausch

Bio: Robert L. Rausch is an academic researcher from University of Washington. The author has contributed to research in topics: Echinococcus multilocularis & Taeniidae. The author has an hindex of 38, co-authored 172 publications receiving 3973 citations. Previous affiliations of Robert L. Rausch include National Institutes of Health.

Studies on the helminth fauna of Alaska. XXV. The ecology and public health significance of Echinococcus sibiricensis Rausch & Schiller, 1954, on St. Lawrence Island.

Abstract: It is concluded that E. sibiricensis is the etiologic agent of alveolar hydatid disease in man. The cestode has a wide distribution in Eurasia, and St Lawrence Island apparently represents the north-easternmost extent of its range. The study of the cestode in Europe has been complicated by the co-existence of E. granulosus, which does not occur on St Lawrence Island. Microtine rodents, particularly Microtus spp. and Clethrionomys rutilus, are the natural intermediate hosts of this cestode, although other species of mammals, including man, are parasitized with varying degrees of success on the part of the larval cestode.

Spontaneous death of Echinococcus multilocularis: cases diagnosed serologically (by Em2 ELISA) and clinical significance.

Abstract: Nine cases of asymptomatic alveolar hydatid disease (AHD) of the liver were diagnosed in 1985 among Eskimos from the endemic region of western Alaska. The patients were identified by screening with the enzyme-linked immunosorbent assay, using purified Echinococcus multilocularis antigen (Em2 ELISA). Five patients, and one diagnosed earlier (1979), were found to have lesions in which the larval E. multilocularis had died spontaneously at an early stage of infection. Viability was assessed histologically; by the avidinbiotin immunohistochemical method; and in vivo through intraperitoneal inoculation of membranes of the larval cestode into red-backed voles, Clethrionomys rutilus. The results were in agreement with the clinical impression, based on findings by computerized tomography and ultrasound scanning, and on the macroscopic appearance of the lesions, that the cestode was dead. Spontaneous death of E. multilocularis in humans has not been previously reported. The findings show that the Em2 ELISA may be positive in patients having lesions of AHD in which the etiologic agent is no longer viable.

On the Status of Some Arctic Mammals

Abstract: Contains a study of mammals of arctic Alaska, mainly from the Brooks Range, each species discussed in terms of holarctic distribution. The information was obtained during investigations by the Animal-borne Disease Branch of the Arctic Health Research Center, Anchorage, Alaska, during which 4,500 mammals were collected. Alaska has about 30 widely distributed species, many circumboreal. These and their varieties are described in systematic order. The grizzly or brown bear wolf, arctic hoary marmot, ground squirrel, tundra vole, narrow-skulled or gregarious vole and caribou are treated in some detail, and the relationship of the caribou to Alaskan Eskimo economy is described. The Romanzof Mts. of the Brooks Range and Arctic Village near the southern limits of the Brooks Range on the East Chandalar River are briefly described. Photographs show skulls, tables give cranial measurements, and maps show Alaskan distribution of various species.

New Aspects of Neotropical Polycystic (Echinococcus vogeli) and Unicystic (Echinococcus oligarthrus) Echinococcosis

Abstract: SUMMARY Of the four species of the genus Echinococcus (Cestoda) distinguished by biological and morphological characteristics, two species, E. vogeli and E. oligarthrus, occur widely in the Neotropics. Approximately 200 cases of polycystic echinococcosis (PE) have been recorded from 12 countries in South America. Following early proliferation of E. vogeli in the human host, typically in the liver, the metacestode usually spreads in the peritoneal and pleural cavities, and numerous organs may be invaded. The clinical characteristics of PE in 81 patients with sufficient information are reviewed. Type I disease consists of polycysts in the liver and abdominal cavity (37% of the patients had this characteristic); type II is similar to type I but also includes hepatic insufficiency (26%); type III consists of cysts in liver and chest (14%); type IV consists of cysts only in the mesenteries (16%); and type V consists of cysts calcified in liver and lung (4%). The percentage of patients with polycysts in the liver was 81%, and the percentage of patients with polycysts in the chest was 14%. PE is most ready diagnosed by geographic origin of the patient and by means of ultrasound or computerized tomography scanning showing cysts and calcifications. The highest mortality was for patients with type II disease, due to hepatic failure and its complications. There were five patients who died due to surgical accidents, whereas 35 cases had uncomplicated surgery. Twenty-three patients died of PE, making the total mortality 29% (23 of 78 cases). None of the 13 patients treated only with albendazole, the most efficacious treatment, was completely cured. PE represents a severe medical problem in South America. A reevaluation of the characteristics of the metacestode of E. oligarthrus indicated that it is unicystic. Only three human cases are known (two with infection in the orbit and one with infection in the heart). The metacestode of E. oligarthrus, in contrast with that of E. vogeli, consists of a spherical, fluid-filled vesicle that enlarges concentrically and is not known to undergo exogenous proliferation.

Studies on the Helminth Fauna of Alaska. XXVII. The Occurrence of Larvae of Trichinella spiralis in Alaskan Mammals

Abstract: An effort was made to obtain a series of each species of mammal occurring in Alaska, with exception of the ungulates. Such specimens were collected over the entire Territory, but most originated above the Arctic Circle. Many mammals were secured through the cooperation of Eskimo and Indian trappers, who held the frozen carcasses of animals taken for their fur until they could be brought to the laboratory in Anchorage. In some instances, only muscle tissue of animals, with collecting data, was preserved. The personnel of the Zoonotic Disease Section also collected large numbers of mammals. Dogs were generally obtained when those no longer serviceable were destroyed, but some were purchased for this study. Although some autopsies were performed in the field, most of the animals were brought entire to the laboratory. For the purposes of this work, several grams of striated muscle were taken, routinely from the diaphragm, at the autopsy of each animal. These samples were frozen and stored for later processing. The larvae were usually dead when isolated. The presence of Trichinella larvae was determined through the artificial digestion of tissue samples. For this purpose, the tissue was chopped with a knife into small pieces, placed in a solution of pepsin and hydrochloric acid, and incubated at 37? C. with constant agitation for 24 hours. The resulting fluid was poured through a fine-mesh screen to remove any undigested material and was allowed to stand in graduated cylinders until any larvae present settled out. The supernatant fluid was siphoned off, the residue placed in watch glasses with a few drops of 10 percent

Biological, Epidemiological, and Clinical Aspects of Echinococcosis, a Zoonosis of Increasing Concern

Abstract: Echinococcosis in humans is a zoonotic infection caused by larval stages (metacestodes) of cestode species of the genus Echinococcus. Cystic echinococcosis (CE) is caused by Echinococcus granulosus, alveolar echinococcosis (AE) is caused by E. multilocularis, and polycystic forms are caused by either E. vogeli or E. oligarthrus. In untreated cases, AE has a high mortality rate. Although control is essentially feasible, CE remains a considerable health problem in many regions of the northern and southern hemispheres. AE is restricted to the northern hemisphere regions of North America and Eurasia. Recent studies have shown that E. multilocularis, the causative agent of AE, is more widely distributed than previously thought. There are also some hints of an increasing significance of polycystic forms of the disease, which are restricted to Central and South America. Various aspects of human echinococcosis are discussed in this review, including data on the infectivity of genetic variants of E. granulosus to humans, the increasing invasion of cities in Europe and Japan by red foxes, the main definitive hosts of E. multilocularis, and the first demonstration of urban cycles of the parasite. Examples of emergence or reemergence of CE are presented, and the question of potential spreading of E. multilocularis is critically assessed. Furthermore, information is presented on new and improved tools for diagnosing the infection in final hosts (dogs, foxes, and cats) by coproantigen or DNA detection and the application of molecular techniques to epidemiological studies. In the clinical field, the available methods for diagnosing human CE and AE are described and the treatment options are summarized. The development of new chemotherapeutic options for all forms of human echinococcosis remains an urgent requirement. A new option for the control of E. granulosus in the intermediate host population (mainly sheep and cattle) is vaccination. Attempts are made to reduce the prevalence of E. multilocualaris in fox populations by regular baiting with an anthelmintic (praziquantel). Recent data have shown that this control option may be used in restricted areas, for example in cities, with the aim of reducing the infection risk for humans.