Pathophysiology of Ichthyophthirius multifiliis infection in rainbow trout (oncorhynchus mykiss) and chub (Leuciscus cephalus).

The present study investigated the effect of experimental infection with Ichthyophthirius multifiliis on physiological, immunological and metabolic parameters in rainbow trout (Oncorhynchus mykiss) and chub (Leuciscus cephalus). Both species developed an immune response against I. multifiliis that was detected in the peripheral blood (i.e. increase in immunoglobulin concentrations in rainbow trout, increase in lymphocyte and thrombocyte concentrations in chub), but not in the skin mucus. Anaemia was observed in both species of fish. In rainbow trout there was also depletion of liver glycogen, disturbance in osmoregulation (decrease in serum osmolality and Na(+) and Cl(-) concentrations) and possibly also impaired wound healing capacity (i.e. decrease in skin mucus alkaline phosphatase and ß-glucuronidase activity). Therefore, rainbow trout develop more severe changes following this infection compared with chub.

Appearance of red mark syndrome/ cold water strawberry disease in Switzerland and Austria.

Red mark syndrome (RMS) or cold water strawberry disease (CWSD) is a non-lethal skin disease of rainbow trout Oncorhynchus mykiss that is of high economic importance in the UK. The disease is temperature-dependent, with up to 60% morbidity at water temperatures below 15 degrees C. Although CWSD is horizontally transmissible, the aetiology is still unknown. Here we describe the first cases of RMS on the European mainland in the alpine regions of Switzerland and Austria. In Switzerland, morbidity remained around 1% after the first outbreak, whereas in Austria no further cases were diagnosed.

Sacbrood virus of the honeybee (Apis mellifera): rapid identification and phylogenetic analysis using reverse transcription-PCR.

Sacbrood virus (SBV) infects larvae of the honeybee (Apis mellifera), resulting in failure to pupate and death. Until now, identification of viruses in honeybee infections has been based on traditional methods such as electron microscopy, immunodiffusion, and enzyme-linked immunosorbent assay. Culture cannot be used because no honeybee cell lines are available. These techniques are low in sensitivity and specificity. However, the complete nucleotide sequence of SBV has recently been determined, and with these data, we now report a reverse transcription-PCR (RT-PCR) test for the direct, rapid, and sensitive detection of these viruses. RT-PCR was used to target five different areas of the SBV genome using infected honeybees and larvae originating from geographically distinct regions. The RT-PCR assay proved to be a rapid, specific, and sensitive diagnostic tool for the direct detection of SBV nucleic acid in samples of infected honeybees and brood regardless of geographic origin. The amplification products were sequenced, and phylogenetic analysis suggested the existence of at least three distinct genotypes of SBV.