The effect of dietary immunostimulants on the susceptibility of common carp (Cyprinus carpio) to the white spot parasite, Ichthyophthirius multifiliis.

One of the main obstacles in freshwater aquaculture is the parasitic ciliate Ichthyophthirius multifiliis (Ich), the causative agent of white spot disease. The use of immunostimulants as feed additives may be a promising approach to control Ich infection. In the present study, we tested the prophylactic effect of orally administered β-1,3/1,6-glucan and propolis extract E50 against Ich infection in common carp.

Whirling disease revisited: pathogenesis, parasite biology and disease intervention.

Whirling disease (WD) is an ecologically and economically debilitating disease of rainbow trout Oncorhynchus mykiss caused by the actinosporean spores of the parasite Myxobolus cerebralis. M. cerebralis has a complex, 2-host life cycle alternating between salmonid fish and the oligochaete host Tubifex tubifex.

Parental genetic diversity of brown trout (Salmo trutta m. fario) brood stock affects offspring susceptibility to whirling disease.

Background: Whirling disease, caused by the myxozoan parasite Myxobolus cerebralis, has high economical and ecological importance worldwide. Susceptibility to the disease varies considerably among salmonid species. In brown trout (Salmo trutta) the infection is usually subclinical with low mortality, which increases the risk of parasite dissemination, especially when farm fish are used for stocking natural habitats.

Biostatic activity of piscine serum and mucus on myxozoan fish infective stages.

Since the basis of host specificity in Myxozoa, i.e. the differential disposition and extinction of erroneously penetrated myxozoan infective stages in non-susceptible fish hosts, remains puzzling, we aimed to explore the role of the innate immune system in this issue.

No shot in the dark: myxozoans chemically detect fresh fish.

This work reports the discovery of an hitherto unknown chemical recognition trait enabling a parasitic life cycle in aquatic habitats. We believe this is the first record of a natural, host-derived chemical molecule identified as a recognition cue for the phylum Myxozoa. The actinospores of these parasites attach to fish hosts via polar filaments that are extruded upon mechanical stimulation after preceding recognition of a chemical trigger contained in surface mucus.

In vivo exposure of susceptible and non-susceptible fish species to Myxobolus cerebralis actinospores reveals non-specific invasion behaviour.

Due to controversial previous results, it has been unclear whether Myxobolus cerebralis (Myxosporea, Myxozoa) is able to specifically choose a salmonid host by selective attachment and penetration. Using a novel in vivo tracking assay that employs fluorescence staining of actinospore sporoplasms, we demonstrate a lack of host specificity of M. cerebralis actinospores during their initial invasion reactions.

Differences in viability and reactivity of actinospores of three myxozoan species upon ageing.

Little is known about the viability of myxozoan actinospore stages after harvest from laboratory cultures of infected oligochaete worms. The viability and reactivity of actinospores of three myxozoan species was evaluated after short-term storage at 4 degrees C and 12 degrees C. Two methods of determining actinospore viability were compared: differential fluorescent staining and direct microscopic observation of morphological indicators of spore integrity.

Life cycle studies of Myxobolus parviformis sp. n. (Myxozoa: Myxobolidae) from bream.

We experimentally followed the life cycle of Myxobolus parviformis sp. n., a myxozoan parasite from the gills of common bream Abramis brama L.

Behavioural strategies used by the hookworms Necator americanus and Ancylostoma duodenale to find, recognize and invade the human host.

The infective third-stage larvae of the hookworms Necator americanus and Ancylostoma duodenale infect their human hosts by active skin invasion, but A. duodenale is in addition capable of oral infection. The behaviour of the larvae when crawling on surfaces has already been described.