Vaccination of Mixed and Full-Sib Families of Channel Catfish Ictalurus punctatus Against Enteric Septicemia of Catfish With a Live Attenuated Edwardsiella ictaluri Isolate (RE-33)

These studies were conducted to evaluate the efficacy of a live attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish. In one study channel catfish fingerlings (72 d of age post hatch) were immersed for 30 min in water containing E. ictaluri RE-33 at dosages of 1 × 10⁶, 1 × 10⁷ and 2 × 10⁷ CFU/ML of water. No mortalities were observed following vaccination. Following exposure to virulent Edwardsiella ictaluri the cumulative mortality of fish vaccinated with dosages of at least 1 × 10⁷ CFU/mL were significantly lower than that of non-vacccinated fish in both laboratory and field challenges. Vaccination with 1 × 10⁶ CFU RE-33mL provided some protection during the laboratory challenge but failed to protect fish under field conditions. In a second study, vaccination of 6 full-sib families of channel catfish at a vaccine dosage of 1 × 10⁷ CFU/mL resulted in a relative percent survival among families ranging from 67.1 to 100%. Significant differences in mortality were found among families and between vaccinated and unvaccinated groups, but there was no family by vaccine interaction. Families with the highest mortality after vaccination were also shown to have the highest mortality without vaccination (r = 0.82; P = 0.04).     

Distribution and depletion of [14C]resmethrin isomers administered orally to laying hens

The cis and trans isomers of the synthetic pyrethroid resmethrin, labelled with radiocarbon in either the alcohol or acid moiety, were individually administered orally to White Leghorn laying hens at a dosage of 10 mg kg^?1. With each isomer and label position, greater than 90% of the radiocarbon was eliminated in the excreta within 24 h after the treatment. Radiocarbon residues in the egg white and yolk fractions were low, with peak levels observed 1 and 4-5 days after treatment in white and yolk, respectively. In birds sacrificed 12 h after treatment, radiocarbon residues in tissues were low; the highest levels were found in the liver and kidney.     

Pathologic Factors Affecting Postsplenectomy Survival in Dogs

The apparently high prevalence of splenomegaly in dogs, along with the surgical accessibility of the spleen, results in a relatively large number of splenectomies in dogs in clinical veterinary practice. Splenic nodular lesions are widely considered to be indicative of hemangiosarcoma and thus a disease that is ultimately fatal. This study correlates the results of complete pathologic evaluation and classification of 500 spleens obtained by splenectomy with survival information for each dog. Among the spleens examined, 257 of 500 (51.4%) were classified nonneoplastic and 241 (48.2%) were neoplastic; 2 (0.4%) were unclassified. Miscellaneous non-nodular splenomegaly accounted for 46 of 257 (18%) of the nonneoplastic lesions; nodular splenomegaly accounted for 206 of 257 (79%) of nonneoplastic splenic lesions and was composed of lymphoid hyperplastic nodules and associated hematomas, hyperplastic lymphoid nodules alone, or hematomas with no apparent underlying cause. Nodular neoplastic diseases of the spleen were divided among benign tumors (11.5%) and a variety of primary sarcomas. Hemangiosarcoma made up 51% of splenic malignancies but accounted for less than 25% of the spleens evaluated. Survival of dogs with hematomas associated with nonneoplastic conditions of the spleen was markedly different from that in dogs with hemangiosarcoma-associated hematomas, even though most could not be effectively differentiated on gross inspection. Two month postoperative survival was 83% for dogs with nonneoplastic-related hematomas, whereas only 31% of dogs with hemangiosarcoma, with or without associated hematomas, were alive after 2 months. Twelve-month survival times were 64% and 7%, respectively. An overall postsplenectomy survival rate of 52% was based on the number of dogs surviving for a minimum of 6 months postoperatively.     

Rocky Mountain spotted fever in dogs and its differentiation from canine ehrlichiosis

Rocky Mountain spotted fever (RMSF) or ehrlichiosis was diagnosed in dogs on the basis of specific immunofluorescent testing for each disease. Comparisons between clinical and laboratory findings were made between the 2 diseases. The incidence of RMSF tended to be more seasonal and it affected younger dogs. Purebred dogs appeared to be more susceptible to both diseases. In general, RMSF had a more rapid and severe course of clinical illness than did ehrlichiosis, but acute ehrlichiosis was difficult to differentiate from RMSF. Both diseases were characterized by fever, depression, lymphadenopathy, and signs of neurologic dysfunction; petechial hemorrhages or other signs of hemorrhagic diathesis were evident only in a small proportion of cases. Anemia, leukopenia, and thrombocytopenia were more common in dogs with ehrlichiosis, whereas those with RMSF more often had leukocytosis and thrombocytopenia. Hypoalbuminemia was found in dogs with both diseases, but those with ehrlichiosis usually had concurrent hyperglobulinemia. High serum alkaline phosphatase activity and serum cholesterol concentration, and low serum calcium concentration were more common in dogs with RMSF than with ehrlichiosis. Rising serum titers or positive direct immunofluorescence for Rickettsia rickettsii in skin biopsy specimens were used to confirm RMSF, whereas a single serum titer for Ehrlichia canis enabled detection of ehrlichiosis. In the absence of neurologic deficits and when dogs were treated with tetracycline, dogs with RMSF made a more rapid and consistent recovery than did dogs with ehrlichiosis.     

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Characteristic site disturbance due to harvesting and extraction machinery traffic on sensitive forest sites with peat soils

The effects of wood harvesting and extraction machinery traffic on sensitive forest sites with peat soils were characterised with the objective of quantifying the threshold levels beyond which significant site impacts (compaction and rutting) would occur. The treatments involved running the machines in selected extraction racks (i.e., 3 m wide machine routes) while conducting normal wood thinning and extraction operations comprising one and two passes by the harvester and the forwarder with full payload, respectively. Soil disturbance thresholds were established by testing the level of significance of the difference in induced soil damage and compaction before and after machine traffic treatments. For volumetric soil water content lying between 10.0 and 14.9%, threshold cone penetration resistance levels for two 600/55–30.5 tyres were found to range from 594 to 640 kPa for deep-raised peat soil with initial strength lying between 524 and 581 kPa. In general, the proportion of the total rut depth data in each rack that exceeded the threshold level of 21.5 cm was about 5%. The threshold value corresponds to sinkage equivalent to 15% of the overall wheel diameter of the harvester, above which machine mobility would be hampered considerably. In addition, after harvester traffic the mean rut depth per unit rack length was 10.2×10⁻² cm/m, and it ranged from 0.7 to 24.7×10⁻² cm/m.     

Surface deterioration of wood-flour polypropylene composites by weathering trials

The market for wood-fiber plastic composites (WPCs) is expanding rapidly in many countries including Japan, where WPCs are mainly used for exterior products. In such applications, WPCs undergo undesirable color change, chalking, and shrinkage and swelling, and accordingly there is a need to better understand the mechanisms responsible for the weathering of WPC and develop methods of improving their weathering resistance. In this study, weatherability of WPC was assessed by natural and accelerated weathering trials. Discoloration (whitening) of WPC during exposure was caused by degradation of both wood and plastic. Darker color pigments as additives improved the color stability of WPC; however, chalking on the surfaces still occurred. The color stability of WPC was improved by application of exterior coatings. Preweathering of WPC (before coatings were applied) increased the absorption of coatings by the WPC and had a positive effect on the color stability and prevented chalking of the composites. Parts of this study were presented at the IUFRO XXII World Congress Meeting, Brisbane, August 2005 and the IAWPS 2005, Yokohama, November 2005     

Antiviral activity of an acidic polysaccharides fraction extracted from Cedrela tubiflora leaves

An acidic polysaccharides fraction (APS) obtained from Cedrela tubiflora leaves was tested for antiviral activity. This fraction inhibited the replication of HSV-2 and VSV, while the replication of poliovirus was not affected. APS was not virucidal, but no cytotoxicity was present in the different concentrations of APS assayed.