Echinococcus Granulosus Infection Research Articles

Possible factors influencing distribution and prevalence of Echinococcus granulosus in Utah.

A descriptive epidemiologic study was designed to test an impression that infections of Echinococcus granulosus in dogs, sheep, and human beings were concentrated in central Utah, and to determine when and how the parasite was introduced into the state, which factors were involved in the distribution of the cestode, and which factors increased either a person's risk of infection of the number of people at risk. Data were secured by review of available records, interviews, questionnaires, and field observations. It was found that 37 of 39 infections in human beings, and seven of eight counties with endemic hydatid disease in dogs and sheep, are located in central Utah. Possible factors responsible for the increasing number of people at risk were use of local people as herders, the existence of community herds, and specific dog management practices. Determinants such as trailing sheep between seasonal pastures, association of sheepmen from several counties on winter range, and sheep marketing practices undoubtedly influence distribution of infections in dogs and sheep.

The effect of route of administration on the efficacy of praziquantel against Echinococcus granulosus infections in dogs

Dogs infected with Echinococcus granulosus were treated with praziquantel by three routes and at different dosage rates. The results indicated that the dog was of similar efficacy when administered by the oral and intramuscular routes, but less effective by the subcutaneous route.

'Arc 5' antibodies in sera of sheep infected with Echinococcus granulosus, Taenia hydatigena and Taenia ovis.

The 'arc 5' precipitin band, formed when test human serum is reacted against immunoelectophoresed hydatid cyst fluid antigen, has provided a positive diagnosis of Echinococcus granulosus infection. These antibodies to 'arc 5' antigen have now been found in the sera of sheep. They appear 2 weeks after infection with Taenia ovis, after 3 weeks with T. hydatigena and after 16 weeks with E. granulosus. An antigen similar to the 'arc 5' antigen of E. granulosus cyst fluid was also demonstrated in cyst fluid from T. hydatigena, but it would not be positively identified in T. ovis cyst fluid. The presence of 'arc 5' in immunoelectrophoresis tests is not suitable for specific immunodiagnosis of E. granulosus infections in sheep in New Zealand. 'Arc 5' antibodies were only associated with living E. granulosus cysts and were not present if cysts were dead. The location of the cysts in either liver or lungs and the onset of brood capsule production did not influence the presence of 'arc 5' antibodies.

An Evolving Pattern of Human Hydatid Disease Transmission in the United States *

Echinococcus granulosus infection was being acquired in the contiguous United States by Virginia sharecroppers and small-holders by the turn of the century. The last recorded human infection from that general area was diagnosed in 1947. By 1920 human infections were also being acquired in the lower Mississippi valley. Apparently, infection in both of these areas was maintained chiefly in swine. By 1940 a third transmission area definitely existed in the Central Valley of California, with its reservoir intermediate host sheep. Seemingly, infection has been disseminated from these California foci into Utah and more recently into northern New Mexico and Arizona. Human populations now at unusual risk in the western United States are transhumant sheep ranchers, including Basque-Americans in California, Mormons in central Utah, and Navajo and Zuni Indians in New Mexico and Arizona. Conditions highly favorable to E. granulosus transmission, intensification and spread now exist throughout relatively large areas of the American West.

Effect of mebendazole on hydatid cysts in pigs

Abstract Mebendazole given per os was found to be effective against larval Echinococcus granulosus infection in pigs. Twenty-four pigs were experimentally inoculated with adult E. granulosus tapeworms. Mebendazole (40 mg/kg) or placebo was injected into six pigs 2 months after infection. Seven other pigs were given mebendazole (25 mg/kg) in their feed for 10 days twice (2 and 5 months after infection). Post-mortem examination performed 8 months after infection revealed that two of the pigs treated with mebendazole per os had a single hydatid cyst each; the other five pigs were free of infection. All eleven control untreated pigs were infected with between two and 21 cysts of E. granulosus . Mebendazole given intraperitoneally was not effective as mebendazole given per os in preventing the development of hydatid cysts in pigs.

Chemotherapy of hydatid disease (Echinococcus granulosus) in mice with mebendazole and bithionol.

We treated female Swiss Webster mice with heavy, long standing infections of Echinococcus granulosus with mebendazole, 50 mg/kg body weight daily for 10 days and bithionol, 70 mg/kg every other day for four doses. Necropsy performed 6 weeks after completion of therapy showed no gross or histologic differences between untreated controls and bithionol-treated mice or their cysts. Mebendazole-treated mice had a significant decrease in the total number of cysts (15 vs. 100), with many of those present being ruptured. Electron microscopy of intact, mebendazole-treated cysts revealed a marked increase in vacuolization and disarray of the distal cytoplasm, dilated and degenerating microtubules, increase in the size and number of lysosomes, a decrease in the number of normal appearing golgi, and increased density of mitochondria. Several mice died shortly after the termination of mebendazole therapy, all with ruptured cysts. Due to the large volume of the cysts, the presumed cause of death was acute volume overload, but toxic or anaphylactic reactions could not be excluded. We suggest that any proposed chemotherapy of humans with hydatid disease be done cautiously, with careful monitoring.

Echinococcosis in Arizona and New Mexico. Survey of hospital records, 1969-1974.

In 1974, seven cases of human echinococcosis were diagnosed in Arizona and New Mexico. A retrospective survey of Arizona and New Mexico hospitals obtained data on ten additional cases reported for the 5-year period 1969 through 1973. Sixteen cases were diagnosed as Echinococcus granulosus infections and one as E. multilocularis infection. The latter infection was in an Eskimo from Alaska, where E. multilocularis is endemic. All of the 16 E. granulosus cases were probably acquired autochthonously; 14 were diagnosed in American Indians of the Navajo (8 cases), Zuni (4 cases), and Santo Domingo (2 cases) tribes; the remaining 2 cases were diagnosed in non-Indian women. This is the first published account of echinococcosis autochthonous to Arizona and New Mexico. Evidence suggests that the infection may have been introduced only relatively recently to the areas populated by the American Indians and that parasite transmission to humans is increasing.

The Occurrence of Echinococcus granulosus in Coyotes (Canis latrans) in the Central Valley of California

As part of epidemiological studies on hydatid disease in the Central Valley of California, a survey was made in 7 counties for possible infections with Echinococcus granulosus in the coyote, Canis latrans. Of 173 animals examined, 7 (4%) were found infected, 6 of them from Tehama County. In previous papers (Sawyer et al., 1969; Schantz et al., 1970) we reported Echinococcus granulosus infections in dogs, sheep, and man in five counties of the Central Valley of California, extending from Colusa County in the north to Kern County in the south. It is clear from these studies that the classical dog-sheep cycle of hydatid transmission is being maintained throughout a sizable area of this state. Despite the fact that coyotes (Canis latrans) are numerous in California, it was not known to what extent, if any, they and other species of wildlife might also be contributing to the maintenance of this cycle. E. granulosus has been reported in C. latrans in Canada (Sweatman, 1952; Miller, 1953; Holmes, 1961; Freeman et al., 1961; Holmes and Podesta, 1968), and Leiby and Carney (1968) have recently observed immature E. multilocularis in five of 15 coyotes in North Dakota. To our knowledge, however, this is the first report of E. granulosus in coyotes in the United States. Infections of deer with this parasite are described from California counties in the accompanying paper by Brunetti and Rosen (1970). MATERIALS AND METHODS Through the cooperation of the Bureau of Sport Fisheries and Wildlife of the U. S. Department of Received for publication 6 January 1970. * These studies were supported in part by NIH research grant AI07857 and a grant from WHO. Please address reprint requests to the Department of Epidemiology and Preventive Medicine, University of California, Davis. t Present address: Department of Veterinary Microbiology, University of California, Davis. + Now with the Centro Pan-Americano de Zoonosis, Ramos Mejia, Buenos Aires, Argentina. ? State Supervisor, Bureau of Sport Fisheries and Wildlife, U. S. Department of Interior, Sacramento, California. Interior contact was established with their district field supervisors and district field assistants in several counties of the Central Valley of California. Field assistants engaged in a predator control program for coyotes were furnished with strong plastic bags, labels, string, and a sheet of instructions. Immediately upon killing a coyote they were asked to tie off the small intestine with adjacent double ties at the pylorus and also at a point about 2 ft distal to the pylorus. The removed section of intestine was to be placed in a plastic bag, together with a label indicating the animal species, the time and place of collection, and the name of the collector. This bag was to be securely tied and placed inside a second plastic bag. It was requested that these specimens be kept as cool as possible during transportation and that they be placed in a deepfreeze as quickly as feasible. Frozen specimens were picked up by us whenever a district field assistant reported by telephone or letter that 10 or more specimens had been collected. They were transported to the laboratory in the frozen state and stored at -20 C until examined. We had found in previous studies that specimens handled in this way were usually satisfactory for recovery and identification of Echinococcus. Intestinal specimens were individually thawed and slit open in a dissecting pan containing water. The mucosa was scraped with a knife and both mucosal scrapings and intestinal contents were washed through an 80-mesh-per-inch brass sieve. The material retained on the sieve was washed into a glass container and examined in a strong light against a black background. Suspected Echinococcus and detached proglottids were removed by disposable Pasteur pipettes and examined microscopically as described previously (Schantz et al., 1969). All containers, instruments, and contaminated surfaces were washed with boiling water (Meymerian and Schwabe, 1962). The examiners wore protective clothing including gowns, masks, caps, and gloves which were autoclaved following each series of examinations.

The efficiency of bunamidine hydrochloride against young Echinococcus granulosus infection in dogs.

The efficiency of bunamidine hydrochloride against young Echinococcus granulosus infection in dogs.

The veterinary surgeon and taeniid worms of farm animals

Abstract Extract The estimated economic loss from condemnations of livers at freezing works, mostly all being due to Echinococcus granulosus infection, amounts to about £1,500,000 per annum on overseas prices for livers. This estimate does not include the potential value from sheep, cattle, and pig lungs for overseas export, but, were these exportable, their value would be quite substantial. Unfortunately, owing to the heavy incidence of worm cysts, this is not possible. Nearly all adult cows and ewes slaughtered at the freezing works are affected. In addition, it has been estimated that about 40 to 50 per cent, of beef cattle, 60 per cent, of lambs, and 20 per cent, of pigs are found at slaughter to show evidence of taeniid infection. While a proportion of lambliver condenmations are due to Taenia hydatigena infection, nearly all the condemnations of adult livers are due to E. granulosus cysts—i.e., hydatid cysts.