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K. M. Kocan

Publications and source records attributed to K. M. Kocan.

4 recordsLinked to original sources
USGS2007

Sequence analysis of the msp4 gene of Anaplasma ovis strains

Anaplasma ovis (Rickettsiales: Anaplasmataceae) is a tick-borne pathogen of sheep, goats and wild ruminants. The genetic diversity of A. ovis strains has not been well characterized due to the lack of sequence information. In this study, we evaluated bighorn sheep ( Ovis canadensis ) and mule deer (Odocoileus hemionus ) from Montana for infection with A. ovis by serology and sequence analysis of the msp4 gene. Antibodies to Anaplasma spp. were detected in 37% and 39% of bighorn sheep and mule deer analyzed, respectively. Four new msp4 genotypes were identified. The A. ovis msp4 sequences identified herein were analyzed together with sequences reported previously for the characterization of the genetic diversity of A. ovis strains in comparison with other Anaplasma spp. The results of these studies demonstrated that although A. ovis msp4 genotypes may vary among geographic regions and between sheep and deer hosts, the variation observed was less than the variation observed between A. marginale and A. phagocytophilum strains. The results reported herein further confirm that A. ovis infection occurs in natural wild ruminant populations in Western United States and that bighorn sheep and mule deer may serve as wildlife reservoirs of A. ovis . ?? 2006.

Veterinary Microbiology↗
USGS1994

Plasma chloride and gill epithelial response of channel catfish to infection with Ichthyophthirius multifillis

Because infection with Ichthyophthirius multifiliis has been reported to result in osmotic stress, genesis of the plasma chloride and chloride cell response of channel catfish Ictalurus punctatus to the infection was studied from day 0 to day 7 postexposure (PE). Parasite population densities ranged from 0.08 to 0.22 trophonts per gill filament during days 1–5 PE and increased to 2.1 at day 7 PE. Population increases were the result of infection by a new generation of infective theronts and reproduction by the parasite on the host. Mean plasma chloride concentrations of fish were not significantly different among days 0–5 PE (range of means, 93.01–97.87 meq/L), but by day 7 PE the mean had declined significantly, to 83.73 meq/L. Maintenance of relatively stable plasma chloride concentrations for 5 d was associated with chloride cell proliferation. The number of interlamellar filament chloride cells had significantly increased by day 1 PE, and the number of chloride cells in the lamellae had significantly increased by day 5 PE. No further increase had occurred by day 7 PE. Vacuolization of chloride cells, examined by electron microscopy, became more common as infection progressed, and many chloride cells appeared to be degenerating by day 5 PE.

Journal of Aquatic Animal Health↗
USGS1994

Loma sp. salmonids from the Eastern United States: Associated lesions rainbow trout

A microsporidian of the genus Loma was noted in the gills of rainbow trout Oncorhynchus mykiss from a state hatchery (Buford Trout Hatchery) in Georgia. Mortalities of varying severity occur at this hatchery every fall, and the microsporidian was noted during an experiment from August 1991 to January 1992 to determine the effects of water source on disease. Infections first appeared to be systemic in the October sample; xenomas were observed in heart, spleen, and peripheral vessel walls. The presence of unidentified intracellular material preceded the appearance of xenomas in all tissues, but whether this material was associated with inflammation or represented immature stages of the parasite has yet to be determined. These structures were also noted in the intestine and liver, although xenomas were not noted in these organs. Mature xenomas did not elicit an inflammatory response but appeared to be short-lived. When the xenoma wall ruptured and released spores, an inflammatory response was again observed. The prevalence and severity of the infection were determined in fish maintained in troughs with well water, Chattahoochee River water, or hatchery (treated river) water. The infection tended to be more prevalent and more severe in fish maintained in the hatchery or river water than in those maintained in the well water. Stress induced by poor water quality may increase mortality from this parasite. This report extends the range of Loma sp. into the eastern United States.

Journal of Aquatic Animal Health↗