Jane E. Huffman

Echinostoma and echinostomiasis.

Publisher Summary This chapter discusses the studies on the biology, life history, infectivity, immunology, pathology, epidemiology, physiology, and biochemistry of Echinostoma . Some studies on other genera of Echinostomatidae are considered as they relate to Echinostoma. The systematics of the 37-collar-spined Echinostoma in the E. revoluturn group is discussed and is based on morphological, biometrical, isoenzymatical, and biological characteristics. The chapter focuses on E. trivolvis, E. caproni, and E. revolutum. Echinostome adults are cosmopolitan, hermaphroditic digeneans that live in the intestines and bile ducts of numerous vertebrate hosts, particularly, aquatic or semi-aquatic birds and mammals. Results derived from the experimental infection of laboratory rodents have provided insight into the pathogenesis of echinostomes. The diagnosis of echinostomiasis is made by recovering the eggs in the feces. The time of deposition of eggs in the feces will vary between species. Species diagnosis is based mainly on the morphological study of the adult worm, which can be obtained after anthelmintic treatment. The transplantation studies and cultivation of Echinostoma in vivo and in vitro are also discussed. The use of echinostomes in physiological, biochemical, and behavioral studies is an untapped resource. Many of the studies done on E. trivolvis need to be performed on E. caproni , E. revohturn , and other echinostomes for comparative purposes. The gross and histopathological effects of echinostome infections are well documented in experimental infections in mice and hamsters.

The biology of the intestinal trematode Echinostoma caproni

Publisher Summary This chapter introduces the biology of the intestinal trematode, Echinostoma cuproni, a good digenean to work with because it can be easily cycled in the laboratory between the medically important planorbid snail, Biomphuluriu glubrutu and laboratory mice or hamsters, the same hosts that are used to maintain, Schistosomu munsoni. The chapter examines the salient features of the biology, life history, infectivity, immunology, pathology, physiology, cultivation, biochemistry, and molecular biology of this organism. The chapter also includes discussion of the ultrastructural studies on the adults, concurrent studies with other parasites both in the snail and the vertebrate hosts, histopathological and pathobiochemical effects of the infection on both the intermediate and definitive hosts, and immunobiology studies in both the intermediate and definitive hosts. Studies using electrophoresis and polymerase chain reaction (PCR) are reviewed. It is concluded that this organism is an exceptionally fine model for various studies in parasitology.

Effects of lead-contaminated surface water from a trap and skeet range on frog hatching and development

Pickerel frogs (Rana palustris) and bullfrogs (Rana catesbeiana) were exposed from the egg stage to lead-contaminated surface water from a trap and skeet range. Seven experimental treatments were employed: 25, 50, 75 and 100% range water, 100% range water plus a chelating agent (sodium citrate), control water and control water plus chelating agent. Total lead concentrations in 100% range water treatments varied from 840-3150 microg litre(-1), with the filterable form accounting for approximately 4-5% of the total. Hatching was not affected in either species (p > 0.2). There were highly significant differences in mortality among treatments for R. palustris (p = 0.0001), with tadpoles exhibiting 100 and 98% mortality after 10 d of exposure to 100 and 75% range water, respectively. Mortality in the 100% range water + citrate treatment was similar to controls (p > 0.05). There were no significant differences in mortality among treatments for R. catesbeiana after 10 d of exposure (p = 0.7119). Exposure to lead in the range water did not adversely affect the growth of surviving R. palustris or R. catesbeiana tadpoles after 14 weeks and 10 weeks, respectively. In both species, the intestinal mucosa in tadpoles exposed to range water was reduced in thickness. Scanning electron micrographs of R. palustris tadpoles that died in 100% range water revealed stunted tail growth, incurvation of the spine, hydropsy and generally reduced body size.

Echinostoma revolutum: pathology of extraintestinal infection in the golden hamster.

Abstract Extraintestinal echinostomiasis, i.e. Echinostoma revolutum adults in sites other than the intestine, occurred in golden hamsters experimentally infected with more than 77 worms. Clinical effects included increased bilirubin concentration, the presence of Escherichia coli in blood samples, a decrease in splenic and an increase in adrenal relative weights. The livers of some hamsters exhibited suppurative hepatitis, peribiliary necrosis, hemorrhage, egg granulomas and fibrosis. Suppurative liver lesions contained Bacillus subtilis, B. cereus and Escherichia coli . Gall bladders and pancreatic ducts contained worms and traumatic necrosis occurred in the ducts followed by an intense inflammatory response in the lamina propria. Parasites were also recovered from the stomachs of two extraintestinally infected hamsters with > 77 worms.

The effects of crowding on adults of Echinostoma caproni in experimentally infected golden hamsters

Fifty-nine of 60 (98%), 6-month-old male golden hamsters, Mesocricetus auratus, fed 15 (group A), 50 (group B), or 200 (group C) metacercarial cysts of Echinostoma caproni (Digenea: Echinostomatidae) were infected 7-34 days postexposure. The mean number of worms recovered in groups A, B and C were 9, 10, and 50, respectively. The percentage recovery was significantly different between group A (63%) and groups B (21%) and C (23%). The intestine was divided into three equal regions (I, II, III). Worms from group A were located in segments II and III of the small intestine whereas worms from groups B and C were distributed in all three segments. The body area, ovarian and testicular areas of worms from group A were greatest, followed in decreasing order by body and gonadal areas of worms from groups B and C. Echinostoma caproni eggs were found in the faeces of all the hamsters examined from groups A, B and C by days 9, 10 and 11, respectively. Physical damage occurred at the site of attachment of the echinostome. Pathological observations indicated the presence of enlarged lymphatic nodules with lymphocytes being the primary cellular infiltrate at the site of parasite attachment.

Single and multiple worm infections of Echinostoma caproni (Trematoda) in the golden hamster

Six of 10 hamsters fed a single metacercarial cyst of Echinostoma caproni (single-worm infections) and 13 of 19 hamsters fed either 2 or 5 cysts (multiple-worm infections) were infected with adult echinostomes at necropsy 22 days post-infection. Considerable histopathological changes to the small intestine occurred in hamsters carrying single-worm infections. There were no differences in either mean length, width or wet weight of echinostomes in single- versus multiple-worm infections. The mean number of eggs/worm from single-worm infections (525) was significantly greater than that from multiple-worm infections (288). The average percentage of fully developed miracidia/worm from single worms (94%) was similar to that from worms in multiple infections (92-95%). Single worms of E. caproni were capable of self-fertilization and production of viable eggs. Miracidia derived from single worms were as capable of infecting laboratory-reared Biomphalaria glabrata and producing patent rediae as were those from multiple infections.

Echinostomes in the second intermediate host

Echinostomes have a wide range of both invertebrate and vertebrate second intermediate hosts. The most studied hosts are molluskan, particularly the gastropods and bivalves; next most studied hosts are the amphibians, particularly tadpoles and frogs. The encysted metacercaria or cyst is the dominant stage in the second intermediate host of echinostomes. This cyst is usually formed in or on tissues of the involved invertebrate or vertebrate second intermediate hosts. In gastropods the preferred site for encystment is usually the kidney or pericardium. In anurans the preferred site is often the kidney or the limb buds in echinostome-like forms such as Ribieroia sp. This chapter reviews the biology, development, distinguishing morphological characteristics, site selection, behavioral changes in vertebrate and vertebrate hosts, pathology, and the effects of pesticides, herbicides, and marinades on the metacercariae of the Echinostomatidae.

Fatty acid composition of Goniobasis virginica, Physa sp. and Viviparus malleatus (Mollusca: Gastropoda) from Lake Musconetcong, New Jersey

Abstract Gas—liquid chromatographic studies were done to determine the fatty acid composition of Goniobasis virginica Physa sp., and Viviparus malleatus (Mollusca: Gastropoda), from Lake Musconetcong, NJ, U.S.A. Palmitic acid was the predominant saturated fatty acid, followed by stearic acid, in all three molluscan species. The chief monoenes were 16: n −7, 18:1 n −7; 20:1 n −11+9, and 22:1 n −11+13, which together accounted for all monoene fatty acids and one-quarter of the total fatty acids. Considerable amounts of linolenic acid (2.7−4.1%) and arachidonic acid (7.8−12%) were found in all three species. The percentage composition of docosahexaenoic acid (22:6 n −3) was low compared to that of eicosapentaenoic acid (22:5 n −3). Non-methylene interrupted dienes (20:2 NMID), characteristic of marine molluscs, ranged from 2 to 3% in the three species of freshwater snails.

Chapter 1. The biology of the caecal trematode Zygocotyle lunata.

This chapter examines the significant studies on the caecal paramphistomid Zygocotyle lunata from mainly 1941 to 2008. This digenean is one of two paramphistomid species in the family Zygocotylidae. Z. lunata has an almost global distribution being found in the wild in numerous waterfowl and various species of ruminants. It infects planorbid snails in the genera Helisoma and Biomphalaria. Because it may involve concurrent infections with Schistosoma mansoni in species of Biomphalaria snails, there is an interest in Z. lunata as a potential control agent against S. mansoni. Z. lunata may have some impact as a pathogen of birds in wildlife diseases, but its real assessment in this role is not fully understood. The cercariae of this paramphistomid when released from snails encyst on a substratum such as vegetation or the shells of aquatic invertebrates in the wild or in the laboratory on the glass or plastic of a container holding the snails. Most studies on the intra-molluscan parasitic stages are based on work from snails collected in the wild and experimental studies using laboratory-reared snails are sparse. Numerous experimental mammalian and avian hosts can be infected with the metacercarial cysts of this digenean, but quantitative experimental studies on the adult stages of this parasite using known numbers of cysts and well-defined strains of vertebrate hosts are sparse. Likewise, some studies on the immunology and pathology of this trematode have been done, but for the most part they are fragmentary and do not provide quantitative information on these topics. Published information on the molecular biology of this organism does not exist. The organism is in need of new research efforts at all levels of organization from the molecular to the community.

Fatty acid composition ofEchinostoma trivolvis (Trematoda) rediae and adults and of the digestive gland-gonad complex ofHelisoma trivolvis (Gastropoda) infected with the intramolluscan stages of this echinostome

Gas-liquid chromatographic studies were done to determine the fatty acid composition of the digestive gland-gonad (DGG) complex ofHelisoma trivolvis snails infected with the intramolluscan stages ofEchinostoma trivolvis, of rediae freed from the DGG, of uninfected DGG, and of 41-day-old adult worms grown in golden hamsters. The DGG of infected snails showed significantly higher levels of stearic acid (18∶0), hexatrienoic acid (16∶3n-4), and docosahexanoic acid (22∶6n-3) than that of uninfected snails. However, the DGG of uninfected snails showed significantly higher levels of 20∶2 non-methylene-interrupted diene (NMID) and adrenic acid (22∶4n-6) than that of infected snails. The profiles of other fatty acids were remarkably similar in both infected and uninfected snails. Adult worms showed significantly higher amounts of numerous saturated fatty acids and dienes as compared with the rediae. However, the rediae showed significantly higher amounts of certain monoenes and trienes as compared with the adults. Fatty acid differences between rediae and adults probably reflect differences in either the available lipid pools in the immediate host sites or the metabolic activity of each stage of this echinostome.