Ovicidal and nymphicidal effects of some fungicides on the greenhouse whitefly<Emphasis Type="Italic">Trialeurodes vaporariorum</Emphasis>

Eggs and L1 nymphs of the greenhouse whiteflyTrialeurodes vaporariorum (Westwood) (Hem.: Aleyrodidae) on bean leaves were directly sprayed with the fungicides maneb and mancozeb at recommended rates for practical use. Strong ovicidal and nymphicidal effects were observed. These fungicides may prove to have practical use for integration in IPM programs for whitefly control, as they also exert low or no toxicity to the whitefly parasitoidEncarsia formosa. http://www.phytoparasitica.org posting April, 30, 2004.     

Host-parasite relationships in tobacco plants infected with a root-knot nematode (<Emphasis Type="Italic">Meloidogyne incognita</Emphasis>) population from the Azores

During a nematode survey, severe infections of tobacco feeder roots and heavy soil infestations byMeloidogyne incognita race 1 were found in S. Miguel (Azores islands, Portugal). This is the first record ofM. incognita infection of tobacco in Azores. Morphology of various life stages, analysis of the esterase electrophoretic pattern and differential host tests were used for nematode characterization and identification. Nematode-induced mature galls were spherical and/or ellipsoidal and usually contained more than one female, males and egg masses with eggs. Feeding sites were characterized by the development of giant cells that contained granular cytoplasm and many hypertrophied nuclei. Giant cell cytoplasm was aggregated along a thickened cell wall. Vascular tissues within galls appeared disorganized. The relationship between the initial nematode population density and growth of tobacco plants was tested in a glasshouse experiment in which inoculum levels varied from 0 to 512 eggs and juveniles (J₂) cm⁻³ of soil. Seinhorst’s model was fitted to height and top fresh weight data of the inoculated and control plants. Tolerance limits with respect to plant height and fresh top weight of tobacco cv. ‘Erzegovina’ plants toM. incognita race 1 were estimated as 1.25 eggs and J₂ cm⁻³ of soil. The maximum nematode reproduction rate was 404.7 at an initial population density of 4 eggs and J₂ cm⁻³ of soil. http://www.phytoparasitica.org posting March 2, 2004.     

Identification of transgenes from wood of genetically transformed poplar trees

We have extracted total DNA from different fractions of fresh wood as well as from cold-stored and air-dried wood harvested from transgenic aspen grown in the field. The highest amounts of DNA were obtained from bark/cambium tissue; the DNA quality, however, was poor. Best results in PCR and Southern blot analyses were obtained from DNA extracted from early wood. Using appropriate primer pairs, amplification products were obtained from both the foreign gene (transgene) and aspen genomic sequences. In Southern blot analyses transgene-specific hybridisation signals were obtained. This is the first report on the detection of foreign genes in wood sampled from genetically modified trees.     

Experimental acute canine monocytic ehrlichiosis: clinicopathological and immunopathological findings

Clinical signs, humoral and cellular immune responses, and microscopic and gross tissue alterations resulting from acute experimental Ehrlichia canis infection in dogs were studied. Four dogs were inoculated with E. canis and four were used as uninfected controls. After a 10-14-day incubation period, infected dogs developed pyrexia up to 41 degrees C for 6-8 days. Antibody titers to E. canis antigen were demonstrable in all inoculated dogs at 30 days post-infection. Necropsy of infected animals revealed pale mucous membranes, generalized lymphadenopathy, splenomegaly, edema and ascites. Microcopically, the main lesions were: lymphoreticular hyperplasia in cortical areas of lymph nodes and spleenic white pulp, periportal accumulation of mononuclear cells and centrolobular fatty degeneration of the liver. Kidneys presented with glomerulonephritis characterized by interstitial mononuclear infiltration. Immunophenotyping of lymphocytes from lymph nodes and spleen sections displayed alterations in IgG, IgM, CD3+ and CD8+ cells population in infected dogs.     

Seroprevalence of Toxoplasma gondii antibodies from wild canids from Brazil

The prevalence of anti-Toxoplasma gondii antibodies was evaluated by the indirect immunofluorescent-antibody test in serum of 57 wild canids from three different species: Lycalopex gymnocercus, Cerdocyon thous and Dusicyon vetulus from the northeast, southeast and southern regions of Brazil. The prevalence was 35.1%, with 20 of the 57 canids demonstrating antibodies anti-T. gondii at dilutions of 1:16 in 2, 1:32 in 4, 1:64 in 2, 1:128 in 2, 1:256 in 6, 1:512 in 2 and 1:2048 in 2 animals. None of the D. vetulus were positive. Among the L. gymnocercus 11 (91.7%) of the 12 samples were positive and among C. thous 9 (60%) of the 15 had antibodies anti-T. gondii.     

Comparison of the sensitivity of in vitro and in vivo tests for detection of the presence of a bovine viral diarrhoea virus type 1 strain

Veterinary vaccines are usually tested for the absence of contaminants. However, the quality control does not always imply that vaccines are not contaminated as, for example, illustrated by the bovine herpes virus 1 (BHV1) vaccine used in The Netherlands in 1999 that contained a small amount of bovine viral diarrhoea virus (BVDV1). Thousands of cows were vaccinated with BHV1 vaccine batches, and the question arose as to whether these small amounts of BVDV1, most likely not detected with in vitro tests, could have infected cattle. More in general, the question was whether the outcome of the in vitro tests, i.e. the in vitro infectivity, was indicative for the infectivity for cattle, i.e. the in vivo infectivity. We therefore carried out in vitro experiments to determine the sensitivity of a BVDV1 isolation assay. In addition, we performed two animal experiments, in which we estimated the lowest dose needed to infect calves with BVDV1. We extrapolated the experimental in vitro and in vivo results from a tissue culture infectious dose (TCID50) to a cattle infectious dose (CID50). We observed a partial response in the calves inoculated with this dose: four out of six calves turned out to be infected. In the tissue culture test, all 20 samples tested negative. The response in vivo, however, was not significantly higher than the in vitro response, which implies that no difference in susceptibility was observed between the animal test and the tissue culture test. Based on the results in our experiments, some cattle may have been infected with BVDV1 after the application of the contaminated BHV1 vaccine during the vaccination campaign. The question remains that how many cattle received contaminated vaccine, and became infected with BVDV1.     

High urinary corticoid/creatinine ratios in cats with hyperthyroidism

Measurement of the urinary corticoid : creatinine (C : C) ratio provides an assessment of cortisol secretion over a period of time. Therefore, this test is a very sensitive measure of adrenocortical function. The stress of the diagnostic procedure and nonadrenal disease may increase the urinary C : C ratio. In addition, diseases such as hyperthyroidism may influence the metabolic clearance of cortisol. To evaluate the effect of thyroid hormone excess, urinary C : C ratios were measured in 32 cats with hyperthyroidism and 45 healthy household cats. In 7 cats, urinary C : C ratios were measured both before and after treatment for hyperthyroidism. With data from the healthy cats, the reference range for the urinary C : C ratio was determined to be 8.0 to 42.0 X 10(-6). The urinary C : C ratios in the cats with hyperthyroidism (median, 37.5 x 10(-6); range, 5.9-169.5 x 10(-6)) were significantly (P = .001) higher than those in the healthy cats (median, 16 x 10(-6); range, 4.8-52.5 x 10(-6)). In 15 cats with hyperthyroidism, the urinary C : C ratios exceeded the upper limit of the reference range. Treatment for hyperthyroidism led to a marked decrease in urinary C : C ratios. The results of this study demonstrate that the urinary C : C ratio may be abnormally high in cats with hyperthyroidism, probably because of increased metabolic clearance of cortisol and activation of the pituitary-adrenocortical axis by disease. Although the clinical features of hyperthyroidism and hyperadrenocorticism in cats are different, hyperthyroidism should be ruled out when cats are suspected of hyperadrenocorticism on the basis of abnormally high urinary C : C ratios.