Seals, fish, humans and parasites in the Baltic: ecology, evolution and history.

Evolutionary and ecological processes affecting the interactions between hosts and parasites in the aquatic environment are at display in the Baltic Sea, a young and ecologically unstable marine ecosystem, where fluctuating abiotic and biotic factors affect the parasitofauna in fish. The dynamic infections of Baltic cod, a subpopulation of the Atlantic cod (Gadus morhua Linnaeus), with third stage anisakid nematode larvae of Pseudoterranova decipiens (Krabbe, 1878) and Contracaecum osculatum (Rudolphi, 1802) have increased following a significant increase of the Baltic grey seal Halichoerus grypus (Fabricius) population in the region. Cod serves as a paratenic host and marine mammals, pinnipeds, are definitive hosts releasing parasite eggs, with faeces, to the marine environment, where embryonation and hatching of the third stage larva take place. The parasite has no obligate intermediate hosts, but various invertebrates, smaller fish and cod act as paratenic hosts transmitting the infection to the seal. Contracaecum osculatum has an impact on the physiological performance of the cod, which optimises transmission of the larva from fish to seal. Thus, a muscle mass decrease of nearly 50% may result from heavy C. osculatum infections, probably amplified by a restricted food availability. The muscle atrophy is likely to reduce the escape reactions of the fish when meeting a foraging seal. In certain regions, where fish and seals are restricted in their migration patterns, such as the semi-enclosed Baltic Sea, the predation may contribute to a severe cod stock depletion. The parasites are zoonotic and represent a human health risk, when consumers ingest insufficiently heat- or freeze-treated infected products. Marked infections of the cod were previously reported during periods with elevated seal populations (late 19th and middle 20th century) and various scenarios for management of risk factors are evaluated in an evolutionary context.

Insights into the role of deep-sea squids of the genus Histioteuthis (Histioteuthidae) in the life cycle of ascaridoid parasites in the Central Mediterranean Sea waters.

Ascaridoid nematodes comprise a wide range of heteroxenous parasites infecting top fish predators and marine mammals as definitive hosts, with crustaceans, squids, and fishes acting as intermediate/paratenic hosts. Limited data exist on the species and role of several intermediate and paratenic hosts in the life cycle of these parasites. In the aim of adding knowledge on the role of squid species in their life cycle, we have here investigated the larval ascaridoid nematodes collected from the deep-sea umbrella squid Histioteuthis bonnelli and the reverse jewel squid Histioteuthis reversa captured in the Central Mediterranean Sea (Tyrrhenian Sea). Morphological study and sequence analysis of the internal transcribed spacer (ITS) regions of the ribosomal DNA (rDNA) and the mitochondrial cytochrome c oxidase subunit 2 (mtDNA cox2) gene locus revealed the occurrence of Anisakis physeteris and of an unidentified species of the genus Lappetascaris. Sequence analysis revealed that specimens of Lappetascaris from both squid species matched at 100% sequences previously deposited in GenBank from larval ascaridoids collected in octopuses of the genus Eledone of the Mediterranean Sea. The Bayesian inference tree topology obtained from the analysis of the fragments amplified showed that Lappetascaris specimens were included in a major clade comprising Hysterothylacium species collected in fishes of the families Xiphiidae and Istiophoridae. As regards the site of infection in the squid host species, A. physeteris larvae predominated (60.7%) in the gonads, while those of Lappetascaris (76.3%) were found infecting the mantle musculature. The overall high values of parasitic load suggest both squid species as transmitting hosts of third stage larvae of Lappetascaris to top predator fishes, as well as the umbrella squid as an intermediate/paratenic host in the life cycle of A. physeteris in the Mediterranean Sea.

The P-glycoprotein repertoire of the equine parasitic nematode Parascaris univalens.

P-glycoproteins (Pgp) have been proposed as contributors to the widespread macrocyclic lactone (ML) resistance in several nematode species including a major pathogen of foals, Parascaris univalens. Using new and available RNA-seq data, ten different genomic loci encoding Pgps were identified and characterized by transcriptome-guided RT-PCRs and Sanger sequencing. Phylogenetic analysis revealed an ascarid-specific Pgp lineage, Pgp-18, as well as two paralogues of Pgp-11 and Pgp-16. Comparative gene expression analyses in P. univalens and Caenorhabditis elegans show that the intestine is the major site of expression but individual gene expression patterns were not conserved between the two nematodes. In P. univalens, PunPgp-9, PunPgp-11.1 and PunPgp-16.2 consistently exhibited the highest expression level in two independent transcriptome data sets. Using RNA-Seq, no significant upregulation of any Pgp was detected following in vitro incubation of adult P. univalens with ivermectin suggesting that drug-induced upregulation is not the mechanism of Pgp-mediated ML resistance. Expression and functional analyses of PunPgp-2 and PunPgp-9 in Saccharomyces cerevisiae provide evidence for an interaction with ketoconazole and ivermectin, but not thiabendazole. Overall, this study established reliable reference gene models with significantly improved annotation for the P. univalens Pgp repertoire and provides a foundation for a better understanding of Pgp-mediated anthelmintic resistance.

New insights into the coexistence of Contracaecum rudolphii A and Contracaecum rudolphii B (Nematoda: Anisakidae) in Phalacrocorax carbo sinensis from Sardinia: genetic variability and phylogenetic analysis.

Contracaecum sp. nematodes are important parasites of fish eating birds that can cause animal health problems. In the present study, specimens of Contracaecum rudolphii sensu lato, from the great cormorant Phalacrocorax carbo sinensis from Sardinia, were characterized based on morphological and molecular data. The morphological analysis allowed to identify all the fourth stage larvae (n = 1918) as Contracaecum sp., and adults, male (n = 5845) and female (n = 8312), as C. rudolphii sensu lato. Population genetics and phylogenetic relationships were inferred based on mitochondrial and nuclear markers. Multiple sequence alignment of the ribosomal internal transcribed spacer showed the coexistence of C. rudolphii A (n = 157), C. rudolphii B (n = 22) and a rare heterozygote of these species. Moreover, mitochondrial markers, namely NADH dehydrogenase subunits I (nad1), cytochrome c oxidase subunit (cox1 and cox2) and small subunit of rRNA (rrnS), showed that the studied C. rudolphii A populations had undergone bottleneck, or founder effect event, subsequent to a rapid population growth and expansion. The observed heterozygote is with a mitochondrial pattern of C. rudolphii B. Although, both Contracaecum species showed high genetic diversity, no genetic structure between localities was detected. Phylogenetic reconstructions supported the paraphyly of the avian Contracaecum species including C. ogmorhini (parasite of otariids).

Contracaecum osculatum (sensu lato) infection of Gadus morhua in the Baltic Sea: inter- and intraspecific interactions.

The subpopulation of Atlantic cod, Gadus morhua, in the eastern part of the Baltic Sea has experienced a significant increase in infections with anisakid nematode larvae of the species Contracaecum osculatum sensu lato (s.l.) since the year 2000. The life cycle of the parasite includes seals and especially the grey seal, Halichoerus grypus, as final hosts, carrying the adult nematodes in the stomach, crustaceans (copepods, amphipods) as first intermediate hosts and various fish species (clupeids, sandeel) including cod as second intermediate/paratenic hosts. Cod with a body length below 28 cm are generally non-infected but experience increasing infection levels when they switch to a piscine diet (infected intermediate/paratenic hosts). We present an overall frequency distribution analysis of worms in 166 cod (body length 30-49 cm) collected in the spawning area over the last 5 years. It shows a fit to the negative binomial distribution, a prevalence of infection of 89.8%, a mean intensity of 29.3 parasites per fish (range 1-377) and a variance/mean ratio of 59.2 (≫1), indicating overdispersion. We present measurements of the adult Contracaecum osculatum (s.l.) specimens in the seal stomach and show that the parasites reach a maximum length of 6.6 cm (females) and 5.8 cm (males). L3s in sprat have a total length from 1to 11 mm whereas the larvae in cod liver are 3-27 mm. A decreasing mean worm length associated with high worm densities in cod (number of nematodes per liver) was recorded. Possible explanations might include timing of feeding on infected intermediate/paratenic hosts, intraspecific competition (crowding) between larvae in cod and host responses (indicated by a significant antibody production in cod against C. osculatum (s.l.) antigens). A significant negative correlation between infection intensity and muscle mass of cod was found, suggesting parasite-induced down-regulation of growth factors in cod.

Detection of DNA from the zoonotic raccoon roundworm Baylisascaris procyonis in a French wolf.

Baylisascaris procyonis is a zoonotic nematode whose main definitive host is the raccoon, an invasive carnivore in Europe introduced from the United States. B. procyonis causes larva migrans with poor prognosis in humans. This parasite was unexpectedly detected in France for the first time upon molecular screening of wolf faecal samples. Because no patent infection was found, the wolf cannot be considered as a definitive host. This discovery of B. procyonis in France nonetheless raises questions about the parasite status of the expanding raccoon populations in the country, which will be investigated in the future.

Some adult and larval nematodes from fishes off New Caledonia.

A collection of nematodes from the Muséum National d'Histoire Naturelle (National Museum of Natural History), Paris, France, was studied. The nematodes had previously been collected from a range of marine fish hosts. The aim of this study was to investigate the identity of these nematodes. Detailed body measurements of the nematodes were taken via light microscopy and where possible first and second internal transcribed spacers (ITS-1 and ITS-2) of ribosomal DNA were subjected to PCR, purified and sequenced. Six species and three larval types were found from a range of fish species and included 13 new host records and two new geographical records. Of the taxa found, Hysterothylacium kajikiae is the only species which may have zoonotic potential. The majority of host fish in this study are edible species, commercially and recreationally fished and frequently incorporated into the cuisine of New Caledonia as raw fish dishes. This study will allow better understanding of the diversity, life cycles, distribution and host-parasite relationships in the New Caledonia area.

Parasitism in Gambusia affinis: Fitness Effects in an Incipient Matrotroph.

Gambusia affinis (western mosquitofish) serves as a host for a variety of larval and adult parasites. Gambusia affinis is also an incipient matrotroph, exhibiting adjustments in post-fertilization provisioning to some offspring within a brood using recently acquired resources. Nutrient transfer to embryos is expected to limit the loss of embryo mass during development resulting in larger offspring. Since larger offspring are more likely to survive, maternal contributions are expected to increase fitness. The presence of parasites, particularly intestinal helminths, potentially reduces body condition and resources available for developing offspring, thereby reducing host fitness. The effects of parasitism on the fitness of G. affinis were investigated in the present study. Fish were collected from 3 sites monthly from June 2015 through August 2016. All helminth parasites were collected during necropsy and identified. Brood size and embryo developmental stage were recorded for each female fish. Additionally, 10 ova/embryos of each developmental stage from each female fish collected from May through August 2016 were haphazardly selected and individually weighed. From 429 female mosquitofish, 5,072 helminths were collected. Brood size varied among collection sites and was positively influenced by maternal body condition, the number of daylight hours, water temperature, and the intensity of both plerocercoid and adult Schyzocotyle acheilognathi. However, brood size was negatively related to the intensity of Neoechinorhynchus cylindratus cystacanth and an increasing number of days between collection and dissection. Embryo weight increased with the presence of either Camallanidae or Contracaecum multipapulatum, embryo developmental stage, and relative host density. These results indicate that some parasitic helminth species negatively affect the fitness of G. affinis, while some positively affect fitness, and that effect can vary with intensity.

Genetic identification and insights into the ecology of Contracaecum rudolphii A and C. rudolphii B (Nematoda: Anisakidae) from cormorants and fish of aquatic ecosystems of Central Italy.

Contracaecum rudolphii (s. l.) is a complex of sibling species of anisakid nematodes having the fish-eating birds belonging to the Family Phalacrocoracidae as final hosts. The great cormorant Phalacrocorax carbo sinensis is parasitized by C. rudolphii A and C. rudolphii B. Adults and L4 specimens of C. rudolphii (s. l.) (N = 3282) were collected in cormorants from brackish and freshwater ecosystems of Central Italy. Third-stage larvae of Contracaecum (N = 882) were obtained from the fish species Dicentrarchus labrax, Anguilla anguilla, Aphanius fasciatus, Atherina boyeri, Leuciscus cephalus, Barbus barbus, and Carassius carassius captured in the same geographical areas of cormorants' standings. Contracaecum rudolphii A and C. rudolphii B were identified by a multilocus genetic approach: allozymes, sequences analysis of the mtDNA cox2, and ITS region of rDNA gene loci. Differential distribution of the two parasite species was observed in different aquatic environments. Contracaecum rudolphii B outnumbered C. rudolphii A in wintering cormorants from freshwater ecosystems; the opposite trend was found in cormorants from brackish water. Analogously, C. rudolphii A larvae were more prevalent in brackish water fish, while C. rudolphii B larvae were found infecting only freshwater fish. The findings seem to confirm that C. rudolphii A and C. rudolphii B would have a life-cycle adapted to brackish and freshwater environments, respectively. A differential feeding behavior of wintering cormorants, the ecology of the infected fish species, and abiotic factors related to early stages of the parasites are supposed to maintain the distinctiveness of the two parasite species' life cycles in the two different aquatic ecosystems.

Infection of Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Nematoda: Ascarididae) in a population of captive crested geckoes, Correlophus ciliatus Guichenot (Reptilia: Diplodactylidae).

Here we report on the infection of captive crested geckos Correlophus ciliatus Guichenot (Reptilia: Diplodactylidae), with adults of the ascaridoid nematode, Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Ascarididae). A population of captive crested geckoes became ill and died within a short period of time. Nematodes were recovered from the crested geckoes examined from within the coelomic cavity, penetrating various organs and migrating through subcutaneous tissues, as well as emerging through the geckos' skin. One gecko was treated with levamisole following surgical excision of nematodes from under the skin; this gecko survived. The potential source of the nematode infection in the captive geckoes is discussed. It is most likely that wild-caught Madagascan mossy geckoes, Uroplatus sikorae Boettger (Reptilia: Gekkonidae), introduced the infection to the colony. Molecular sequences of the nematodes are the first produced for the members of this genus. A redescription of the species and its genetic characterization based on the internal transcribed spacer sequence data is provided, suggesting some of the morphological criteria that have been used in the past to distinguish between Hexametra spp. may have been intraspecific morphological variations.

Differential survival of 3rd stage larvae of Contracaecum rudolphii type B infecting common bream (Abramis brama) and common carp (Cyprinus carpio).

The main fish host reaction to an infection with third stage anisakid nematode larvae is a response in which host immune cells (macrophages, granulocytes, lymphocytes) in affected internal organs initially are attracted to the parasite whereafter fibroblasts may enclose the parasite forming granuloma. Generally, the reaction is non-lethal to the parasite which may survive for years in the fish host retaining infectivity to the final host. This may also apply for the anisakid nematode Contracaecum rudolphii (having the adult stage in cormorants, using copepods as first intermediate/paratenic host and zooplankton feeding fish as paratenic hosts). The present study has shown that most Contracaecum rudolphii larvae survive in bream (Abramis brama) (from Lake Balaton, Hungary) whereas the majority of the nematode larvae die in Cyprinus carpio (from Lake Hévíz, directly connected to Lake Balaton). Both cyprinid host species interacted with the nematode larvae through establishing a marked cellular encapsulation around them but with different effects. The differential survival in common carp and bream may theoretically be explained by ecological factors, such as the environmental temperature which either directly or indirectly affect the development of nematode larvae, and/or intrinsic host factors, such as differential immune responses and host genetics.

Baylisascaris procyonis infection in raccoons: A review of demographic and environmental factors influencing parasite carriage.

Baylisascaris procyonis, the roundworm of raccoons (Procyon lotor), is an emerging helminthic zoonosis in North America. Since the larval form is capable of causing neurological disease in more than 150 species of birds and mammals including humans, understanding factors that influence carriage of the parasite by raccoons is important for mitigating risk. This review examines the current literature to identify major demographic and environmental risk factors associated with B. procyonis carriage in wild raccoons. Raccoon age and season of sample collection were most commonly identified as risk factors, with increased prevalence found in juvenile animals and when sample collection occurred in the fall. Human urbanization and agricultural land use were also observed as potential risk factors; however, there are inconsistencies in the direction of influence these risk factors have on the prevalence of infection. Further investigation into the role of environmental risk factors is required to better understand how human activities influence parasite carriage in raccoons. Additionally, future research using multivariable statistical models guided by epidemiological principles to control for confounding variables and identify interaction effects will help clarify the effect of these demographic and environmental factors. Developing a better understanding of the primary risk factors for parasite carriage in raccoons will help identify areas of higher risk for environmental contamination and will aid in the development and refinement of education and management programs to reduce the risk of human exposure.

Species of Contracaecum Parasitizing the Magellanic Penguin Spheniscus magellanicus (Spheniscidae) from the Argentinean Coast.

Anisakid nematodes have a worldwide distribution and are associated with fishes, birds, and marine mammals from freshwater, brackish, and marine systems. The aims of this work are to report for the first time Contracaecum mirounga parasitizing the Magellanic penguin Spheniscus magellanicus, to report another Contracaecum species in the same host species, and to discuss the validity of Contracaeceum spheniscus. Several dead chicks, juveniles, and adults of S. magellanicus were collected along the Argentinean coast from 2002 to 2009. Nematodes were removed from digestive tracts and studied using both light and scanning electron microscopy. Nematode prevalences were 2.38% for C. mirounga and 12.5% for Contracaecum sp. Contracaecum mirounga was found in 1 penguin from Península Valdés, Chubut. This species is known as a specific parasite of marine mammals such as Pinnipedia, thereby suggesting that this nematode is not as specific as believed. Another species of Contracaecum sp. was found parasitizing 1 penguin from the Río de la Plata coast. It possessed an unusual interlabial morphology and arrangement of male caudal papillae. Despite the low prevalence, the distinct morphological features are convincing and support the presence of a new Contracaecum species. However, a formal description is not presented because sufficient male specimens are lacking. Finally, C. spheniscus is considered a junior synonym of Contracaecum pelagicum. Future molecular studies might be helpful to determine the real diversity of Contracaecum species parasitizing S. magellanicus considering the number of sibling species recognized among the anisakids.

Transcriptome and metabolome analyses of Coilia nasus in response to Anisakidae parasite infection.

Parasites from the family Anisakidae are capable of infecting a range of marine fish species worldwide. Coilia nasus, which usually feeds and overwinters in coastal waters and spawns in freshwater, is highly susceptible to infection by Anisakidae. In this study, we used scanning electron microscopes to show that C. nasus infected by Anisakidae exhibited damage and fibrosis of the liver tissue. To better understand host immune reaction and metabolic changes to Anisakidae infection, we used a combination of transcriptomic and metabolomic method to characterize the key genes and metabolites, and the signaling pathway regulation of C. nasus infected by Anisakidae. We generated 62,604 unigenes from liver tissue and identified 391 compounds from serum. Of these, Anisakidae infection resulted in significant up-regulation of 545 genes and 28 metabolites, and significant down-regulation of 416 genes and 37 metabolites. Seventy-four of the 961 differentially expressed genes were linked to immune response, and 1, 2-Diacylglycerol, an important immune-related metabolite, was significantly up-regulated after infection. Our results show activation of antigen processing and presentation, initiation of the T cell receptor signaling pathway, disruption of the TCA cycle, and changes to the amino acid and Glycerolipid metabolisms, which indicate perturbations to the host immune system and metabolism following infection. This is the first study describing the immune responses and metabolic changes in C. nasus to Anisakidae infection, and thus improves our understanding of the interaction mechanisms between C. nasus and Anisakidae. Our findings will be useful for future research on the population ecology of C. nasus.

Determination of the specific gravity of eggs of equine strongylids, Parascaris spp., and Anoplocephala perfoliata.

Given the ever-increasing levels of anthelmintic resistance in livestock parasites globally, it is recommended to use parasite fecal egg counts to make treatment decisions and to evaluate treatment efficacy. The consensus in equine parasitology is to use a flotation medium with a specific gravity (SG) of ≥ 1.20 to float the main parasite egg types of interest in egg counting techniques. However, the density of common equine endoparasite eggs has been sparsely investigated. Equine tapeworm eggs are known to be particularly difficult to determine and count in fecal samples. It is unknown whether this could be because of differences in egg density. The aim of this study was to provide estimates of relative densities for equine ascarid, strongyle, and tapeworm eggs. Six aqueous glucose-salt solutions with specific gravities ranging from 1.06 to 1.16 were made and placed from most to least dense into thirteen 15 mL centrifuge tubes. Concentrated aqueous suspensions of the three types of endoparasite eggs were placed on top of each tube. These tubes were then centrifuged at 800 g for 20 min and each layer of flotation solution was carefully pipetted and transferred to a McMaster egg counting slide. Egg type and count were recorded for each specific gravity layer. Each egg was assigned a specific gravity based on the specific gravity layer it was observed in. In a second trial of this study, five similar flotation media were made ranging from 1.02 to 1.10 and were used in four subsequent replicates. In total between the two trials, the mean egg SGs of Anoplocephala perfoliata (n = 3811), Parascaris spp. (n = 3478), and strongylid type eggs (n = 9291) were 1.0636 (95% confidence interval (CI): 1.0629-1.0642), 1.0903 (95% CI: 1.0897-1.0909), and 1.0453 (95% CI: 1.0448-1.0458), respectively. The three egg types were statistically different from each other (p < 0.0001). This is the first time that the specific gravity of equine strongylid and Anoplocephala perfoliata eggs has been determined. With a tapeworm egg density demonstrated to be between that of strongylids and Parascaris spp., the poor recovery of tapeworm eggs in equine fecal samples must have other explanations.

Larva Migrans of Baylisascaris potosis In Experimental Animals.

Occurrence of clinical signs by infection with Baylisascaris potosis, the roundworm of kinkajous ( Potos flavus), in mice, rats, and rabbit were studied, and the migration behavior of larvae in mice were compared with that of Baylisascaris transfuga, the roundworm of bears ( Ursus spp.). Three groups of 8 mice, 3 groups of 6 rats, and 3 groups of 2 rabbits were inoculated with either 10, 100, or 1,000 B. potosis eggs. The other 8 mice were inoculated with 1,000 B. transfuga eggs. Animals were monitored for the occurrence of clinical signs until 60 days postinoculation (DPI). The carcass, viscera, brain, and eyes of each of 6 mice inoculated with 1,000 eggs of B. potosis or B. transfuga at 60 DPI were removed individually, and the number of larvae was counted. One mouse inoculated with 100 B. potosis eggs showed rolling at 27 DPI, and 1 larva was found in the medulla oblongata of this mouse. No clinical signs were observed in the other mice or in the rats and rabbits. A mean of 387.2 larvae was recovered from mice inoculated with 1,000 B. potosis eggs, and a mean of 422.0 larvae from mice inoculated with 1,000 B. transfuga eggs. The highest number of larvae was recovered from the carcasses for both B. potosis and B. transfuga. In the viscera, higher numbers of B. transfuga larvae (mean 131.8) were seen than B. potosis larvae (mean 33.1). In the brain, only 1 larva was detected in 1/6 mice inoculated with 1,000 B. potosis eggs, whereas a mean of 21 larvae was detected in mice inoculated with 1,000 B. transfuga eggs. A few larvae (range 0-1) were detected in the eyes of both mice inoculated with B. potosis or B. transfuga eggs. The result indicated that B. potosis larvae do not show a higher tendency to migrate into the brain of mice than B. transfuga larvae. However, 1 mouse inoculated with 100 eggs had 1 larva in the central nervous system and showed a serious neurological sign. This result may underline a potential risk of B. potosis to cause neural larva migrans in humans.

Association between urticaria and nematode infections.

BACKGROUND: The association between parasites and urticaria was first suggested in the last century. A wide range, 0-75.4%, of the prevalence of parasitic infection has been reported with chronic urticaria (CU). Moreover, urticaria may be detected in patients with parasitosis. Nematodes are a type of helminth that infect hundreds of millions of people throughout the world. OBJECTIVE: The aim of this work was to collect and review the published studies and cases of urticaria associated with nematode infections. METHODS: A search of scientific literature data bases from January 1960 until May 2017 was carried out. RESULTS: Numerous nematode infections have been associated with urticaria and/or angioedema: Anisakis simplex, Ascaris species (spp.), Dirofilaria spp., Enterobius vermicularis, Gnathostoma spp., Loa loa, Mansonella streptocerca; Necator americanus, Onchocerca volvulus, Strongyloides stercoralis, Toxocara spp., Trichinella spp., and Wuchereria bancrofti. The pathogenesis of urticaria in these infections generally remains unexplained. In some cases, skin manifestations were caused by the presence of the worm in the skin (Filaria, Gnathostoma); in other cases, such as A. simplex and S. stercoralis infections, there was a clear immunoglobulin E-mediated mechanism that led to allergic reactions, and infection and allergy coexisted; for other nematodes, the association was anecdotal and only a few cases were reported. CONCLUSION: It is difficult to detect a certain causal effect, except when urticaria improves or disappears after infection treatment. Cases of isolated urticaria not associated with other symptoms rarely may be caused by helminths. In the current guideline for urticaria, parasitosis is considered to be a rare possible cause of CU in developed industrial countries, Therefore, although a routine screening of parasitic infection in CU is not recommended, in our opinion, testing a patient with urticaria for parasites is a physician's choice based on the characteristics of the patient, such as associated symptoms, dietary habit, provenance country and previous travel.

Extrusion of Contracaecum osculatum nematode larvae from the liver of cod (Gadus morhua).

Baltic cod livers have during recent years been found increasingly and heavily infected with third-stage larvae of Contracaecum osculatum. The infections are associated with an increasing population of grey seals which are final hosts for the parasite. Heavy worm burdens challenge utilization and safety of the fish liver products, and technological solutions for removal of worms are highly needed. We investigated the attachment of the worm larvae in liver tissue by use of histochemical techniques and found that the cod host encapsulates the worm larvae in layers of host cells (macrophages, fibroblasts) supported by enclosures of collagen and calcium. A series of incubation techniques, applying compounds targeting molecules in the capsule, were then tested for their effect to induce worm escape/release reactions. Full digestion solutions comprising pepsin, NaCl, HCl and water induced a fast escape of more than 60% of the worm larvae within 20 min and gave full release within 65 min but the liver tissue became highly dispersed. HCl alone, in concentrations of 48 and 72 mM, triggered a corresponding release of worm larvae with minor effect on liver integrity. A lower HCl concentration of 24 mM resulted in 80% release within 35 min. Water and physiological saline had no effect on worm release, and 1% pepsin in water elicited merely a weak escape reaction. In addition to the direct effect of acid on worm behaviour it is hypothesised that the acid effect on calcium carbonate in the encapsulation, with subsequent release of reaction products, may contribute to activation of C. osculatum larvae and induce escape reactions. Short-term pretreatment of infected cod liver and possibly other infected fish products, using low acid concentrations is suggested as part of a technological solution for worm clearance as low acid concentrations had limited macroscopic effect on liver integrity within 35 min.

Molecular diagnosis of Pseudoterranova decipiens s.s in human, France.

BACKGROUND: Anisakis and Pseudoterranova are the main genera involved in human infections caused by nematodes of the Anisakidae family. Species identification is complicated due to the lack of differential morphological characteristics at the larval stage, thus requiring molecular differentiation. Pseudoterranova larvae ingested through raw fish are spontaneously eliminated in most cases, but mechanical removal by means of endoscopy might be required. To date, only very few cases of Pseudoterranova infection have been reported in France. CASE PRESENTATION: A 19-year-old woman from Northeastern France detected, while brushing her teeth, a larva exiting through her mouth. The patient who presented with headache, diarrhea, and abdominal cramps reported having eaten baked cod. The worm was a fourth-stage larva with a size of 22 × 0.9 mm, and molecular biology identified it as Pseudoterranova decipiens sensu stricto (s. s.). In a second P. decipiens infection case, occurring a few months later, a worm exited through the patient's nose after she had eaten raw sea bream. CONCLUSION: These two cases demonstrate that Pseudoterranova infection is not uncommon among French patients. Therefore, molecular techniques should be more widely applied for a better characterization of anisakidosis epidemiology in France.

Nodular typhlocolitis, heterakiasis, and mesenchymal neoplasia in a ring-necked pheasant ( Phasianus colchicus) with immunohistochemical characterization of visceral metastases.

A 9-y-old, male ring-necked pheasant ( Phasianus colchicus) was autopsied following euthanasia because of acute distress, recumbency, and dyspnea. The bird had experienced a protracted period of neuromuscular disease localized to the left sciatic nerve. Gross and histologic examination of the large intestine revealed intramural nodules predominantly comprised of atypical, whorling spindle cells with small cores of granulomatous inflammation centered on cross-sections of immature adult nematodes. The body structures of these metazoan organisms and clinical disease manifestation are consistent with Heterakis isolonche infection. Nodular spindle cell proliferations without granulomatous inflammation or intralesional nematodes were also found throughout the liver and lungs, suggesting metastasis from the intestine. Immunohistochemical staining of the hepatic and pulmonary tumor tissue with vimentin and S100 suggests a neurofibroblastic origin.