Small Fluke Research Articles

Surveillance Model of Parasitic Zoonosis in Cyprinoid Fishes in Northern Zone and Northeastern Zone of Thailand and Myanmar Using GIS

The parasitic zoonosis, opisthorchis viverrini has been an important public health problem in many parts of the globe. In Thailand, fish-borne parasitic zoonosis is highly spread in the northern and northeastern regions, where a large impact of cholangiocarcinoma occurs, a crucial source of the liver cancer. The rare occasions reports date published about the Opisthorchiasis in the middle zone of Myanmar. In our study, a total of a few species of fish borne trematode metacercariae i.e.; three kind of small intestinal flukes, the family of Heterophyidae; Haplorchoides sp., Haplorchis pumilio, Haplorchis taichi and one species of carcinogenic liver fluke, the family of Opisthorchiidae; Opisthorchis viverrini have been detected from seven study areas from Thailand and Myanmar. The geographic information relevant with the rate of infection with vulnerable species of freshwater fishes was also posted from Thailand and Myanmar, and built a parasitic diseases combine with georeference for Geographical Information System (GIS) implementation. Furthermore, secondary descriptive analysis of the prevalence of fishborne trematodes metacercariae from countries of golden triangles (Southeast Asia) ie; Thailand, Myanmar, and Laos PDR have been created a GIS database for infection status of parasite infections. The outcome from this study may be helpful in strategies for protocol of the prevention of parasitic zoonosis in freshwater fishes reportin Thailand and Myanmar.

Euryhelmis squamula (Digenea: Heterophyidae) Recovered from Korean Raccoon Dog, Nyctereutes procyonoides koreensis, in Korea.

In this study, we intended to describe an unrecorded species of heterophyid trematode recovered from the small intestine of a Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. A total of 13 small flukes were collected from a deceased Korean raccoon dog which was found in Chuncheon-si, Gangwon-do, Korea in May 2017. The trematode body were covered with many small spines, rectangular, broader than long, 807–1,103 μm long and 1,270–1,550 μm wide. Oral sucker in the anterior end slightly smaller than acetabulum. Pharynx muscular and well developed. Esophagus relatively long and sigmoid. Acetabulum small and located at median in anterior 2/5 portion. Ceca bifurcated at the anterior of genital pore and acetabulum and terminated at testis level. Testes larger, deeply lobed and located at the near of posterior end of body. Ovary small, triangular and located at the slight left of median and the anterior of left testis. Vitelline follicles dendritic and extend from the middle level of esophagus to the posterior portion of body. Eggs embryonated, operculated, small and 33–35×15–16 μm in size. Based on the morphological characteristics, the small heterophyid flukes recovered from the small intestines of Korean raccoon dog, N. procyonoides koreensis, were identified as Euryhelmis squamula (Digenea: Heterophyidae). Accordingly, this species of heterophyid flukes is to be a new trematode fauna in Korea by this study.

Current Knowledge of Small Flukes (Digenea: Heterophyidae) from South America.

Fish-borne heterophyid trematodes are known to have a zoonotic potential, since at least 30 species are able to infect humans worldwide, with a global infection of around 7 million people. In this paper, a ‘state-of-the-art’ review of the South American heterophyid species is provided, including classical and molecular taxonomy, parasite ecology, host-parasite interaction studies and a list of species and their hosts. There is still a lack of information on human infections in South America with undetected or unreported infections probably due to the information shortage and little attention by physicians to these small intestinal flukes. Molecular tools for specific diagnoses of South American heterophyid species are still to be defined. Additional new sequences of Pygidiopsis macrostomum, Ascocotyle pindoramensis and Ascocotyle longa from Brazil are also provided.

STUDY ON THE RELATIONSHIP BETWEEN PARASITIC INFECTION AND KNOWLEDGE, HYGIENIC PRACTICAL MEASURES OF PARASITIC INFECTIOUS PREVENTION IN VINH THAI COMMUNITY

Introduction: Intestinal parasite infections werecommonintropical country such as Vietnam. Having good knowledge of parasitic infectious prevention and changing risk behaviors can decrease the infection rate. Objective: To evaluate the parasitic infectious rate in Vinh Thai community before and after being health education and the changing of knowledge of parasitic infectious prevention and risk behaviors. Materials and methods: 60 households in Vinh Thai commune were interviewed their knowledge of parasitic infectious prevention and examined intestinal parasite infection by Kato technique and then trained the knowledge of parasitic infectious prevention. The interview and examination parasite infectiousrate were carried out after 6 months to evaluating their knowledge. Result: Before health education, the rate of intestinal parasite infection was 17.4% with the prevalence of Ascaris lumbricoides, hookworm, whipworm, pinworm, small fluke worm and co-infection with A. lumbricoides - whipworm, hookworm-whipworm were 0.1%; 8.0%; 5.8%; 0.6%; 0.3%; 1.2% and 3.0% respectively. Six months later the rate of intestinal parasite infection was decreased in 12.6% even though not statistical significantly. However, there were no case of small fluke worm and co-infection with hookworm-whipworm. Receiving health education, their knowledge of parasitic infectious prevention was higher significantly but their risk behaviors were not changed so much. Conclusion: Health education can change the rate of parasite infection with higher knowledge of parasitic infectious prevention but it was necessary continuous study to change the risk behaviors. Key words: intestinal parasite, health education

Distribution of hepatic stellate cells and their role in the development of parasitic fibrosis and liver cirrhosis in domestic animals

Increasing of the extracellular matrix in rats, as well as in humans, occurs as a consequence of hepatic stellate cells (HSCs) activity. The objective of this work was to investigation the role of these cells in the development of fibrosis and liver cirrhosis which occurs as a consequence of infection of sheep and goats with large (Fasciola hepatica) and small (Dicrocoelium dendriticum) fluke. Liver samples taken from 12 cattle and 10 sheep infected under natural conditions with large and small fluke were fixed in formalin and embedded in paraffin. Paraffin clips were stained with hematoxylin- eosin and masson trichrome method, and immunohistochemical method for ?-smooth muscle actin (?-SMA). All tested samples were divided into three groups according to histological criteria: livers of infected animals with the first degree of fibrosis, livers of infected animals with the second degree of fibrosis, and livers of infected animals with cirrhosis. Distribution of HSCs depended on the degree of liver fibrosis. Immunohistochemically reactive HSCs were predominantly placed in perisinusoidal space. In liver samples with cirrhosis, HSCs were placed on the periphery of pseudolobulus. Cells of a different shape and size were positive to ?-SMA. HSCs play an important role in synthesis of components of extracellular matrix during the development of parasitic fibrosis and liver cirrhosis in domestic animals.

Prevalence ofMetagonimusMetacercariae in Sweetfish,Plecoglossus altivelis, from Eastern and Southern Coastal Areas in Korea

The present study was performed to determine the current infecion status of Metagonimus yokogawai metacercariae in sweetfish, Plecoglossus altivelis, collected from several streams in eastern and southern coastal areas of Korea. The sweetfish collected were artificially digested with pepsin-HCl solution and examined under a stereomicroscope in August and September, 2007. Out of 145 sweetfish collected from 10 streams in eastern coasts (Gangwon-do and Gye-ongsangbuk-do), 88 (60.7%) were infected with Metagonimus metacercariae. The average metacercarial density was 61 per infected fish. Among 141 sweetfish collected from 10 streams in southern coasts (Gyeongsangnam-do, Ulsan Metropolitan city, and Jeollanam-do), 140 (99.3%) were infected with Metagonimus metacercariae, and their average density was 949 per infected fish. The present study confirmed that M. yokogawai metacercariae are still prevalent in the sweetfish from several eastern and southern coastal localities. The prevalence and metacercarial density were much higher in the sweetfish from streams of southern coasts than in those of eastern coasts. Therefore, attention should be paid to this small fluke infection, and consumption of raw sweetfish naturally produced in these areas should be prohibited.

Eosinophilic proliferative pylephlebitis in the liver of Japanese beef cattle with fascioliasis.

Intrahepatic pylephlebitis was detected in 17 Japanese beef cattle. Grossly, the intrahepatic vessels in the caudate lobe and/or in the periphery of the other hepatic lobes were thickened and protruded above the lobar surface. The vessel lumina were packed with white to red, waste thread-like contents. A few immature flukes were found in the bile ducts in 3 of the 7 cases with biliary thickening. Foci of hepatic necrosis and hemorrhage were scattered around the thickened vessels in 8 cases. Histologically, the interlobular veins were thickened due to severe intimal hyperplasia with endothelial proliferation and eosinophilic accumulation and medial hypertrophy, accompanied by fibrosis and eosinophilic infiltration in the portal areas. Hepatic tissues with necrosis and hemorrhage were surrounded by eosinophils and histiocytes including a granulomatous reaction. One immature fluke was detected in one of these regions of necrosis. Immunoperoxidase staining revealed that the small fluke, Kupffer cells, and histiocytes in the liver of all cases were positively stained with anti-Japanese Fasciola sp. antiserum. Enzyme-linked immunosorbent assay of the sera of 15 cases revealed that all were positive for the anti-Fasciola antibody. On the basis of these findings, the present cases were regarded as an atypical form of fascioliasis, characterized by eosinophilic proliferative pylephlebitis of the liver.

Human Opisthorchis and Haplorchis infections in Laos

A study of the epidemiology of trematode infections was carried out in Vientiane province, Laos, comprising examination of snails, fish, cats, and human stools. Opisthorchis viverrini cercariae were found in the snail Bithynia siamensis goniomphalus (Bithyniidae) and Haplorchis taichui cercariae in Tarebia granifera (Thiaridae). O. viverrini metacercariae were recorded in the flesh of 7 species of cyprinid fish; metacercariae of the heterophyid fluke Haplorchis taichui were found in 4 species of cyprinid fish and those of H. pumilio in 2 species. Cats from the same localities were infected with O. viverrini and 4 species of heterophyid flukes, frequently as multiple infections. The highest prevalence of small fluke eggs in human stools was recorded in the 20–29 years age group, particularly in males (90·4%). Three-quarters of human infections were light (< 1000 eggs/g), the highest value (2975 eggs/g) being recorded in the 10–14 years age group. Identification of small flukes excreted by Laotian patients after treatment with praziquantel in Czechoslovakia revealed more cases with H. taichui than with O. viverrini. The results confirmed the simultaneous occurrence of O. viverrini and intestinal heterophyid flukes in the area studied.

ON THE HETEROPHYID TREMATODA (HETEROPHYES HETEROPHYES) INFECTION CASES IMPORTED FROM EGYPT TO JAPAN

Ten Japanese who had come back from Cairo, Egypt to Japan after three months to two years of stay at Cairo were examined on the stools by the sedimentation mothod. The ova of heterophyid trematoda were detected in the feces of four persons. The cases were treated with Kamala (6 g/patient) and a kind of small flukes could be collected from the passed feces. On microscopical examination these small flukes were identified as H. heterophyes from their morphological characterisitcs. Especially the large number (64-82) of the spines which form a crown on the muscular gonotyle makes it distinguishable from other closely related heterophyid species.Although many patients of H. heterophyes nocens have so far been reported in Japan, H. heterophyes has not been reported yet, and H. heterophyes occurs commonly among cats, dogs, foxes and human beings at Cairo.In Cairo, a Japanese restaurant was opened at November, 1978. and in this restaurant these patients used to eat “Sashimi”, raw fishes of many kinds, including the brachish water fishes which could serve as the second intermediate hosts.This parasite is known to cause diarrhea which may occasionally be accompanied with bloody stools. Further, according to the observations of Africa et al. (1935-'37), it can produce the fatal cardiac and cerebral failure in man; the serious impairments which have never been encountered in the Japanese cases of H. h. nocens. It is highly possible that many more cases of H. heterophyes would be imported. Therefore, it is recommended to cure all these cases, desirably before they would serve as reservoir to spread this new disease in Japan.

Resistance to reinfection with Fasciola hepatica in rabbits

When rabbits were infected each with 10 metacercariae of Fasciola hepatica, reinfected with 20 metacercariae 12 weeks later, and killed at 20 weeks from the time of first infection, the number of flukes recovered was smaller than would have been expected from consideration of the sum of the number recovered when the two infections were given separately. This apparent decrease in numbers probably results from an inhibition of growth as a result of increasing numbers and the technical difficulty of recovering very small flukes.

Eurytrema procyonis Denton, 1942 (Trematoda:Dicrocoeliidae), from the Domestic Cat

Eurytrema procyonis was described by Denton (1942) from racoons in Texas. Stunkard (1947) found a species in a red fox from New York State which he (lescribed and named Eurytrema vulpis. Later, on comparing his specimens with some received from Denton, Stunkard concluded that they were of the same species and that E. vulpis is a synonym of E. procyonis (Stunkard and Goss, 1950). Since then E. procyonis has been found in a racoon in Connecticut (Penner, et al, 1954) and in racoons and gray foxes in Maryland (Herman, et al, 1957). On July 31, 1959, a stray cat from New Jersey was examined in this Laboratory for intestinal helminths and dicrocoeliid-type eggs were found in the feces. At autopsy 67 small flukes were found in the bile ducts and gall bladder and over 300 were tightly packed in the pancreatic ducts. (Another stray cat from New Jersey taken on February 29, 1960, was found at autopsy to have 28 Eurytrema procyonis in the distal portion of the pancreatic duct.)

Ariolimax columbianus, an Intermediate Host for Brachylaemus virginiana (Dickerson) (Trematoda: Digenea) in California

On March 3, 1951 a young male opossum was captured in Tilden Park, Contra Costa Co., California. The animal had a droopy, sickly appearance and was killed and examined for parasites. Several hundred small flukes, later identified as Brachylaemus virginiana (Dickerson), were found in the small intestine. Several months previously one of us had found metacercariae in the kidney of Ariolimax columbianus. This slug is commonly found in the Pacific Coast region and is restricted to this area. Comparison of the metacercariae with the flukes obtained from the opossum, as well as examination of pertinent literature (Dickerson 1930, Krull 1935), indicated clearly that the larvae from the slugs were metacercariae of Brachylaemus virginiana. Of 97 Ariolimax columbianus collected on the Mills College Campus, Alameda Co., California, 94 harbored this metacercaria in the kidneys. There were approximately two dozen larvae per kidney, while specimens with as few as one or two and others with as many as 50 or more were observed. In addition, 6 out of 8 Ariolimax columbianus from Berkeley, Alameda Co., California were infected. Seven A. californicus brachycephalus from San Mateo Co., California were found to be negative. Although the digestive, hermaphroditic and albumen glands were examined in several specimens of A. columbianus, no sporocysts or cercariae were found. Krull (1936) listed 1 slug and 5 snail intermediate hosts for Brachylaemus virginiana. We therefore examined a number of common gastropods, in order to determine possible additional hosts for the larval stages of this fluke. Of 20 Milax gagates, 10 Limax marginatus, 1 Limax flavus, 20 Deroceras reticulatum and 6 Helminthoglypta arrosa holderiana not a single one was infected. All these gastropods were collected on the Mills College Campus between February and May 1951 in the same habitat with Ariolimax. Three Helminthoglypta nickliniana from Tilden Park, Contra Costa Co., California, were also negative. Since the slug Deroceras laeve is a host for the metacercaria (Krull, 1936) one would expect that D. reticulatum might also be suitable. This was not so, however, and it was somewhat surprising to find the metacercariae only in Ariolimax. It may be that the food habits of the above mentioned gastropods are in part responsible for this situation. Ariolimax columbianus has been observed to congregate around and feed on feces in nature. None of the other species listed has been observed to do so. In relation to the opossum in California, we should like to stress that this animal was introduced into the state, the earliest record being sometime after 1880 (Grinnell, Dixon and Linsdale, 1937); subsequently it was introduced repeatedly around

An outbreak of Parasitic Necrosis in Turkeys caused by Plagiorchis laricola (Skrjabin)

A turkey poult sent for post-mortem examination to the Veterinary Research Division, Ministry of Agriculture, Northern Ireland, was found to be suffering from a very heavy infection of a small fluke.

The Life Histories and Classification of Two Allocreadiid-Like Plagiorchids from Fish, Macroderoides typicus (Winfield) and Alloglossidium corti (Lamont)

In examining snails collected in the region of the University of Michigan Biological Station, located on Douglas Lake in the northern part of the Southern Peninsula of Michigan, nineteen species of Xiphidiocercariae were found. These cercariae were placed with a wide variety of organisms in order to determine their second intermediate hosts. The metacercariae which developed were then fed to 24 species of animals, representing all classes of vertebrates. Two of the species of these cercariae were in this way proved experimentally to be those of Macroderoides typicus and Alloglossidium corti. The details of the experimental work and the morphology of the stages of these two species are discussed in the present paper. The cercariae of both species were found developing in small sporocysts in Heliosoma trivolvis and H. campanulata. The incidence of infection with the cercaria of M. typicus was relatively high and infected snails were collected from several areas in Douglas Lake, Burt Lake, and Mullet Lake. The cercariae were found experimentally to penetrate into several possible intermediate hosts but tadpoles were used in the infection of the definitive host. Experimentally infected tadpoles were fed to Amia calva and large numbers of trematodes, identified as Macroderoides typicus (Winfield), were recovered from the intestine. The incidence of infection with the cercaria of A. corti was relatively high in the snails collected in Munro Lake and lower in those from several areas of Douglas Lake. It was experimentally demonstrated that this cercaria would penetrate into and encyst in dragonfly and mayfly nymphs. The metacercariae from these hosts were fed to small, trematode-free bullheads and adult flukes, identified as A. corti (Lamont), were recovered from the small intestine.

New Parasites of the Genus Orientophorus, n.gen. (Family Fellodistomidae) from an Indian Fresh-Water Fish, Clupea ilisha

The family Fellodistomidae Nicoll 1913 comprises two subfamilies, Fellodistominae Nicoll 1909 and Haplocladinae Odhner 1911, which are composed of a large number of genera of small flukes, all parasitic in fishes. The type genus of the family was described by Stafford in 1904 from the gall bladder of a Canadian wolf-fish, Anarrhichas lupus. Subsequently several new genera have been added from European and American fishes, but until now no representative of the family has been reported from India.