Occurrence of infection by Platynosomum illiciens (Braun, 1901) in captive neotropical primates.

Platynosomum illiciens (Trematoda, Plagiorchida) is a trematode parasite reported in felids and falconiforms. It was identified in the gall bladder of eight captive neotropical necropsied primates from the National Primate Center (CENP), Ananindeua, State of Pará, Brazil. This is the first description of Platynosomum illiciens as a parasite of primates.

Human infections of fish-borne trematodes in Vietnam: prevalence and molecular specific identification at an endemic commune in Nam Dinh province.

The prevalence of fish-borne trematodes in humans and their molecular identification was investigated in the Rang Dong commune of Nam Dinh province, Vietnam, between January 2009 and December 2010. A total of 405 people in this commune were interviewed on the habit of eating raw fish and all of their stool samples were collected using the Kato-Katz technique for examination of the presence of fish-borne trematodes. The worms (and eggs) were first morphologically examined, counted, described and identified, then the representative isolates were subjected for molecular species confirmation. A total of 385 adult flukes collected from 10 patients were morphologically identified to species and defined as Clonorchis sinensis (14.58%) in Opisthorchiidae family, Haplorchis taichui (32.29%), Haplorchis pumilio (52.08%) and Centrocestus formosanus (1.04%) in Heterophyidae family. A high rate (77.8%) of the interviewees was found to have the habit of eating raw fish. This habit was attributed to the high infection rate of fish-borne trematode in humans (22.72%; OR=2.486). The infection rate of fish-borne trematodes in males was higher (29.3%) than that in females (16.0%) and increased by age, reaching the highest in the patients aged 40-59 years (28.2-28.7%). The infection intensity of fish-borne trematode was found light (336 EPG). Adult flukes were collected from a group of the patients with the highest intensity of infection and subjected to molecular and phylogenetic analysis using a portion (326 bp) of mitochondrial cox1. Phylogenetic tree inferred from cox1 sequences using sequence data for 34 isolates of opisthorchid, heterophyid, fasciolid, paragonimid, schistosomid trematodes and taeniid cestodes revealed that they are distinct groups. The newly collected with the known clonorchid and heterophyid isolates form the well defined taxonomic groups, respectively, confirming that C. sinensis and Haplorchis spp. (H. pumilio and H. taichui) were among the collected samples.

Trichobilharzia regenti: host immune response in the pathogenesis of neuroinfection in mice.

Besides their natural bird hosts, Trichobilharzia regenti cercariae are able to penetrate skin of mammals, including humans. Experimental infections of mice showed that schistosomula of this species are able to avoid the immune response in skin of their non-specific mammalian host and escape the skin to migrate to the CNS. Schistosomula do not mature in mammals, but can survive in nervous tissue for several days post infection. Neuroinfections of specific bird hosts as well as accidental mammalian hosts can lead to neuromotor effects, for example, leg paralysis and thus this parasite serves as a model of parasite invasion of the CNS. Here, we show by histological and immunohistochemical investigation of CNS invasion of immunocompetent (BALB/c) and immunodeficient (SCID) mice by T. regenti schistosomula that the presence of parasites in the nervous tissue initiated an influx of immune cells, activation of microglia, astrocytes and development of inflammatory lesions. Schistosomula elimination in the tissue depended on the host immune status. In the absence of CD3+ T-cells in immunodeficient SCID mice, parasite destruction was slower than that in immunocompetent BALB/c mice. Axon injury and subsequent secondary demyelination in the CNS were associated with mechanical damage due to migration of schistosomula through the nervous tissue, and not by host immune processes. Immunoreactivity of the parasite intestinal content for specific antigens of oligodendrocytes/myelin and neurofilaments showed for the first time that schistosomula ingest the nervous tissue components during their migration.

Update on hepatobiliary flukes: fascioliasis, opisthorchiasis and clonorchiasis.

PURPOSE OF REVIEW: Hepatobiliary flukes--Fasciola, Opisthorchis, Clonorchis- are a major public health problem in east Asia, east Europe, Africa and Latin America. The present review focuses on current knowledge of clinical, diagnostic and treatment aspects caused by hepatobiliary flukes that can be applied to current protocols in endemic areas. RECENT FINDINGS: Specific risk factors and geographic areas for these flukes have been heavily reported recently, with millions of people infected worldwide. Human cases in nonendemic areas, related to immigration and the international food trade (i.e. raw vegetables and fish), have also been reported. Diagnostic imaging changes include track-like lesions that are a characteristic feature of acute fascioliasis on computed tomography scanning of the liver. Newly available diagnostic serological tests may detect early infection and, therefore, help reduce severe clinical complications such as recurrent cholangitis, cholecystitis, hepatic tumours, cysts, calcification, cholelithiasis, pancreatitis, most importantly, cholangiocarcinoma related to Opisthorchis viverrini and possibly Clonorchis sinensis, and liver fibrosis associated with Fasciola hepatica infections. Highly effective antiparasitic treatment is available for all flukes. SUMMARY: There is a better understanding of risk factors, clinical manifestations and complications, novel diagnosis tests and effective treatment, which together should help reduce the morbidity and mortality of these infections.

[Swimming in summer]. / Zwemmen in de zomer.

It happens every summer: 'Swimming prohibited because of cyanobacteria'. Blooming of these toxine producing bacteria in warm summer months is a well known risk for swimming human beings. But how big is this risk for swimming dogs? And how big are other risks? In this article these risks are assessed for dogs that occasionally swim in surface water during the summer in the Netherlands. Based on these findings an advice will be given for dog owners to keep these risks for waterborne infections as small as possible.

Prevalence of Heterophyes nocens and Pygydiopsis summa infections among residents of the western and southern coastal islands of the Republic of Korea.

To determine the distribution and prevalence of heterophyid fluke infections on coastal islands of the Republic of Korea, fecal specimens were collected from 4,179 people residing on 45 islands in the West (Yellow) and South Seas and examined using the formalin-ether and Kato-Katz techniques. Eggs of Heterophyes nocens were found in 459 (11.0%) residents of 42 islands, with an average number of eggs per gram (epg) of feces of 79.6. Eggs of Pygidiopsis summa were found in 49 (1.2%) on 12 islands, with an average epg of 253.0. The egg-positive rate for H. nocens was the highest on Chungdo (32.6%), followed by Imchado (27.3%); P. summa was most prevalent on Imchado (15.2%). The majority (78.9% [362 of 549] of those infected with H. nocens and 81.6% [40 of 49] of those infected with P. summa) of those infected were adults more than 40 years old. Adult flukes of these species were recovered from residents of Imchado by treatment with praziquantel and purgation. Our results indicate that H. nocens and P. summa are indigenous to the southern and western coastal islands of the Republic of Korea.

A focus of human infection by Haplorchis taichui (Trematoda: Heterophyidae) in the southern Philippines.

We report an exceptionally high rate of infection by Haplorchis taichui (Nishigori, 1924) in human populations on Mindanao Island, southern Philippines. This intestinal fluke is seldom encountered, and this is the first report of high prevalence of infection (36%) in humans by H. taichui in the Philippines. The likely source of haplorchine infection has been linked to consumption of raw or undercooked freshwater fish containing infective metacercariae. The most common clinical symptoms appeared as upper abdominal discomfort or pain and borborygmi. Praziquantel (75 mg/kg divided in 3 doses in 1 day) was a well-tolerated and effective treatment for infection by H. taichui.

The food-borne trematode zoonoses of Vietnam.

During the past couple of decades, numerous surveys for the occurrence and distribution of food-borne trematodes in Vietnam have been carried out. However, the majority of the data obtained have not been published in international journals, and therefore, the seriousness of these trematode parasitic zoonoses in the country has not been fully appreciated. To correct this, over 40 Vietnamese language reports and local publications were translated and organized as a status review for an international audience. The results show that such serious trematode zoonoses as clonorchiasis, opisthorchiasis, paragonimiasis and fascioliasis are common in many regions of Vietnam, and, in the case of fascioliasis and paragonimiasis, are increasing. Data on the species of intermediate hosts involved in the transmission of these zoonoses, and the effect of host sex and age on infection frequencies are presented, along with findings on food preference/behavior investigations. Finally, the authors present recommendations for further research to provide a more comprehensive picture of the status of these zoonoses, and to obtain the risk assessment information needed to design prevention and control programs.

Parasitic diarrhea in normal and malnourished children.

Diarrhea is only one of the many manifestations of intestinal parasites. Environmental influences are inescapable, regardless of an individual's state of health: in a highly endemic region, intestinal parasitic colonization is almost the rule. The clinical expression of the parasitoses, however, is largely determined by host defenses; and when they are weakened, parasitic diarrhea is frequent and severe. Protein-energy malnutrition is by far the most important cause of immune deficiency in developing countries. Diarrhea caused by Strongyloides or Giardia is common and severe in malnourished children, while well-nourished children remain healthy carriers. These parasites require specific treatment in the malnourished; and the well-nourished should have preventive treatment when they are to receive corticosteroids or immunosuppressive agents. Diarrhea caused by Cryptosporidium spp. may be severe in malnourished or immunodeficient children, and recovery is achieved only after renutrition or treatment of the immunodeficiency.

Clinostomum trematode from human eye.

The first human case of Clinostomum lacramalitis in Thailand is reported. A 38-year-old man visited an ophthalmology clinic after having itchy pain in the right eye for two days. Ophthalmological examination revealed a living worm adhered to the lacramal opening and after removal, it was identified as Clinostomum sp. The patient admitted that he used to eat raw freshwater fish, he caught in Prachin Buri Province where he lives.

Public health importance and risk factors for cercarial dermatitis associated with swimming in Lake Leman at Geneva, Switzerland.

Fifteen cohorts of healthy bathers were recruited at four Lake Leman beaches between 3 July and 23 August 1996 to assess the public health importance of cercarial dermatitis in Geneva, Switzerland. Telephone follow-up interviews were carried out after 2-7 days. Overall, 153 bathers out of 555 reported probable cercarial dermatitis at follow-up. Median daily attack rate was 27.7% (2.2-57.7%). Of the cases, 11.1% noticed more than 30 skin lesions, 19.6% described severe itching, 50.3% used a drug treatment, 3.9% visited a doctor and 15% claimed they would reduce their bathing activities. History of cercarial dermatitis, time spent in the water, hour of the day, barometric pressure and maximum daily atmospheric temperature predicted disease occurrence in multivariate analysis. While a benign disease, cercarial dermatitis may have a negative impact on the local water recreation industry. The identification of risk factors for the disease may help produce better preventive recommendations for the bathers.

The epidemiology of cercarial dermatitis and its association with limnological characteristics of a northern Michigan lake.

Cercarial dermatitis (swimmer's itch) is an annoying inflammatory response to penetration of skin by non-human schistosome parasites while swimming or wading in lakes. The purpose of this survey was to identify risk factors for cercarial dermatitis and to determine whether limnological characteristics of the lake were associated with development of the condition. Starting 1 June 1993, an active case surveillance system was established in the communities around Walloon Lake, Michigan, which continued until 30 August 1993; controls were randomly selected weekly during the same time period through telephone surveys. A total of 317 cases of cercarial dermatitis occurring in 146 clusters was identified over the course of the summer and 295 controls were selected from the weekly telephone surveys. Factors associated with the development of cercarial dermatitis identified in the study included age, the time of day at which exposure to lake water occurred, and the month in which exposure to lake water took place. In addition, development of cercarial dermatitis was significantly associated with exposure to lake water in the area of the lake with the highest algae content and shallowest depth.

A human case of Plagiorchis muris (Tanabe, 1922: Digenea) infection in the Republic of Korea: freshwater fish as a possible source of infection.

A Korean man was found infected with Plagiorchis muris and 2 other intestinal trematodes, Echinostoma hortense and Metagonimus takahashii. No complaint of gastrointestinal discomfort due to these fluke infections was noted. The patient had a history of eating various kinds of freshwater fish caught from a small stream near his village. Freshwater fish collected from the stream were examined for trematode metacercariae by an artificial digestion technique. Unidentified metacercariae collected were administered to a Sprague-Dawley rat. One P. muris adult was recovered from the small intestine of the rat on day 8 postinfection. Thus, freshwater fish of the genera Liobagrus, Puntungia, and Odontobutis are a probable source of infection for this patient.

Locally acquired Brachylaima sp. (Digenea: Brachylaimidae) intestinal fluke infection in two South Australian infants.

Eggs of a small intestinal trematode were found in the faeces of two 21-month-old children from the same rural district of South Australia who presented 18 months apart with mild abdominal pain and diarrhoea. Treatment with praziquantel resulted in egg clearance and resolution of gastrointestinal symptoms. A brachylaimid intestinal trematode involving the common house mouse, poultry and introduced European helicid snails is well established in South Australia. Both infants had been seen eating raw snails, and snails from their environment were found to be infected with metacercariae of a brachylaimid trematode.

[The etiology and diagnosis of "black spot disease" of fish]. / Ob étiologii i diagnostike "chernopiatnistogo zabolevaniia" ryb.

Some traditional points of view on the black spot disease in fishes caused by the metacercariae of the trematode Posthodiplostomum cuticola are revised. The black spot disease should be considered as one of several symptoms appeared in freshwater and sea fishes in cases of infection with certain parasite species. Up to present days, more than 30 parasite species causing similar symptoms are recognized. And among them 8 such species have been recorded in fishes of the Volga-Caspian region.

Common-source outbreak of acute infection due to the North American liver fluke Metorchis conjunctus.

BACKGROUND: We investigated an outbreak of acute clinical illness among 19 people who ate raw fish (sashimi) prepared from the white sucker, Catostomus commersoni, caught in a river north of Montreal, Canada. METHODS: We collected epidemiological, clinical, laboratory, and serological data on 19 individuals who ate the sashimi and six who did not. Because of the suggestive clinical picture, we set out to recover helminth parasites from uneaten fish. FINDINGS: The illness consisted of persistent upper abdominal pain, low grade fever, high blood eosinophil concentrations, and raised liver enzymes. After 10 days, opisthorchild-like eggs were found in stools. Symptoms persisted for 3 days to 4 weeks without treatment, but responded rapidly to praziquantel therapy. Necropsy of golden hamsters infected with metacercariae from uneaten fish revealed adult flukes identified as Metorchis conjunctus. INTERPRETATION: We describe an acute illness caused by the North American liver fluke M conjunctus. This is a new human disease and is the first report of a common-source outbreak of an acute illness caused by liver flukes of the family Opisthorchiidae.

Study of the body surface of Haplorchis yokogawai (Katsuta, 1932) and H. taichui (Nishigori, 1924) (Trematoda:Heterophyidae).

The morphology of the surface of two heterophyid flukes, Haplorchis yokogawai and H. taichui, that can infect humans eating raw fish flesh, has been studied using scanning and transmission electron microscopy. The body surface of both species is covered with scale-like, serrated spines with the exception of areas around the oral sucker, ventrogenital opening and excretory pore. The species slightly differ by the dentation pattern of tegumental spines: H. yokogawai has finer and more numerous spine teeth (maximum tooth number 14-16) while H. taichui has more serrated spines, mostly with a lower number (up to 10-12) of somewhat more robust teeth. However, because of the variability, the shape and dentation of spines do not seem to be reliable diagnostic features enabling mutual differentiation of both species.

Differential susceptibility to a trematode parasite among genotypes of the Mytilus edulis/galloprovincialis complex.

We show that parasitism by the trematode Prosorhynchus squamatus in parental and introgressed Mytilus edulis/galloprovincialis (Bivalvia) mussels occurs in individuals with a predominantly M. edulis genome. This result suggests that the restricted specificity of P. squamatus is dependent on genetic factor(s) present in M. edulis. Because of its strong pathogenic effects (i.e. total castration and possible death), this parasite may be a source of intense selection against M. edulis genomes when they are present in a site. As a consequence, it may favour the geographic extension of the M. galloprovincialis genome. Previous studies have indicated that, in hybrid zones, recombinant genotypes are more susceptible to parasitic infections than either parental genotype. We demonstrate that this is not the case for the M. edulis/M. galloprovincialis system, and that the parental genotype alone determines susceptibility.