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.
- MeSH
- Ascaridoidea * fyziologie MeSH
- ekosystém MeSH
- Gadus morhua * parazitologie MeSH
- larva fyziologie MeSH
- lidé MeSH
- nemoci ryb * epidemiologie parazitologie MeSH
- paraziti * MeSH
- ryby MeSH
- tuleňovití * parazitologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Freshwater pulmonate snails from three locations in Lake Furesø north of Copenhagen were screened for infection with furcocercariae (by shedding in the laboratory) and recovered parasite larvae were diagnosed by molecular methods (by performing PCR of rDNA and sequencing the internal transcribed spacer [ITS] region). Overall prevalence of infection in snails was 2%. Recovered cercariae from Lymnaea stagnalis (Linnaeus) were diagnosed as Diplostomum pseudospathaceum Niewiadomska, 1984 (prevalence 4%) and cercariae from Radix balthica (Linnaeus) as D. mergi (Dubois, 1932) (prevalence 2%). Pathogen-free rainbow trout were then exposed to isolated cercariae and infection success and site location of metacercariae in these fish were determined. Infection experiments confirmed that both species could infect rainbow trout with the eye lens as infection site for the metacercarial stage although infection success differed. Combination of molecular and biological assays may contribute to improvement of our knowledge on diagnosis, distribution and biology of diplostomids in fish.
- MeSH
- ekologie MeSH
- fylogeneze MeSH
- hlemýždi parazitologie MeSH
- infekce červy třídy Trematoda parazitologie přenos veterinární MeSH
- jezera parazitologie MeSH
- metacerkárie MeSH
- mezerníky ribozomální DNA chemie genetika MeSH
- molekulární sekvence - údaje MeSH
- nemoci ryb parazitologie přenos MeSH
- Oncorhynchus mykiss parazitologie MeSH
- organismy bez specifických patogenů MeSH
- polymerázová řetězová reakce veterinární MeSH
- roční období MeSH
- ryby MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA veterinární MeSH
- sladká voda parazitologie MeSH
- Trematoda genetika izolace a purifikace fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Dánsko MeSH
Response mechanisms of rainbow trout Oncorhynchus mykiss (Walbaum), experimentally infected with a Danish strain of Gyrodactylus salaris Malmberg, 1957 were investigated using molecular tools (qPCR) and immunohistochemistry. Expression of ten immune-relevant genes and reactivity with five different antibodies in the epidermis of skin and fin tissue were analysed in susceptible but responding rainbow trout. Rainbow trout were susceptible with regard to the parasite strain which initially colonised fins but relocated to the body region as infection progressed. The ten investigated genes encoding the cytokines IL-1ß, TNF-?, IFN-?, IL-10 and markers for adaptive immune activity, such as CD-4, CD-8, TCR-?, IgM, IgT and MHC II, were not found significantly regulated during the course of infection although IFN-? showed a slight up-regulation. Immunohistochemical analyses showed positive reactivity with antibodies against CD3, B-lymphocytes, neutrophilic granulocytes and collectin but not with mAb against IgM. No staining differences between infected and non-infected skin and fin tissue were detected.
- MeSH
- financování organizované MeSH
- infekce červy třídy Trematoda MeSH
- končetiny parazitologie patologie MeSH
- kůže metabolismus parazitologie patologie MeSH
- nemoci ryb parazitologie MeSH
- Oncorhynchus mykiss MeSH
- regulace genové exprese imunologie MeSH
- Trematoda genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- MeSH
- finanční podpora výzkumu jako téma MeSH
- hlen imunologie MeSH
- interakce hostitele a parazita fyziologie MeSH
- kapři parazitologie MeSH
- krevní plazma imunologie MeSH
- losos parazitologie MeSH
- ploštěnci MeSH
- pstruh parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
