Effects of Temperature and Crowding on the Pathogenicity of Edwardsiella ictaluri in Channel Catfish (Ictalurus punctatus)

Channel catfish were injected with Edwardsiella ictaluri and stocked at increasing temperatures and densities. Bacteriological examination of kidney, liver and spleen revealed the greatest numbers of organisms in fish from the highest temperature and stocking density tested. Survival time was the shortest for fish held at the highest temperature and stocking density. Increased temperature and crowding were directly proportional to the number of organisms recovered from the organs and inversely proportional to fish survival time

Distribution of Naegleria fowleri in Selected Northeast Arkansas Lakes

Seven northeast Arkansas recreational lakes were examined for the presence of pathogenic and nonpathogenic Naegleria fowleri. Cultural differentiation and microscopic morphology were used as species determining tests, while mouse pathogenicity tests were conducted to determine virulence. Only one isolate met all criteria utilized for definite identification of Naegleria fowleri, although Naegleria type organisms were found in all of the lakes. None of the isolates were pathogenic in mice

Prevalence of Borrelia burgdorferi, the Lyme Disease Spirochete, in Ticks and Rodents in Northeast Arkansas

Lyme disease, caused by the spirochete, Borrelia burgdorferi, has been reported from 36 of Arkansas\u27 75 counties. Ticks and wild rodents from nine northeast Arkansas counties were surveyed to determine the prevalence of Borrelia infection in potential tick vectors and reservoir host populations. In direct immunofluorescent assays with murine monoclonal antibody H5332, specific for B. burgdorferi, detected a 2.1% rate of infection for the 638 ticks surveyed and an 11.8% infectivity rate for the 102 rodents surveyed

Effects of Bacterial Lipopolysaccharide on Plasma Corticosterone Concentrations and Body Temperatures of New Zealand Rabbits (Oryctolagus cuniculus)

Twelve New Zealand rabbits were injected with Salmonella typhosa endotoxin, 10 ng/kg b.w. ,via an auricular marginal vein and the effects of the pyrogen on the rectal temperatures and plasma corticosterone concentrations of these animals were observed. Our data showed significant increases of the core temperatures from the normal 39.3 +/- 0.18 to 40.9 +/- 0.43 C (p \u3c 0.001). Radioimmunoassay results of the plasma corticosterone levels were 5.76 +/- 3.7 ug/100 ml in the pre-injection blood samples and 9.02 +/- 3.7 ug/100 ml in the plasmas obtained from the animals, one hour after the pyrogen was administered. The increase of corticosterone was significant (

Metabarcoding assays for the detection of freshwater mussels (Unionida) with environmental DNA

Freshwater mussels of the order Unionida are a widely distributed taxon that are important in maintaining freshwater ecosystems and are also highly imperiled throughout the world. Monitoring of mussel populations with environmental DNA (eDNA) is an attractive alternative to traditional methods because it is noninvasive and requires less labor and taxonomic knowledge from field personnel. We developed eDNA metabarcoding assays specific to freshwater mussels and tested them at six sites in the Clinch River, located in the southeastern United States. Our objective was to determine the utility of eDNA metabarcoding for future monitoring of mussel populations and restoration efforts in this watershed. Two metabarcoding assays that target the mitochondrial DNA regions of the cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit (ND1) genes were developed and tested. Our assays appear to be order specific, amplifying members from the two families found in North America, Unionidae and Margaritiferidae, while not amplifying nontarget fish or other bivalve species. From the field collected samples, our assays together detected 19 species, eight of which are listed as federally endangered. The assays also detected 42%, 58%, and 54% of the species identified by recent quantitative visual mussel surveys at three sampling sites. Increased sampling effort by processing a greater water volume or number of samples will likely increase species detections. These eDNA metabarcoding assays may enable enhanced monitoring of freshwater mussel assemblages and subsequently inform conservation efforts