Diagnostic specificity, sensitivity and cross-reactivity of an enzyme-linked immunosorbent assay for the detection of antibody against Leptospira interrogans serovars pomona, sejroe and hardjo in cattle.

Outer sheath antigen was prepared from Leptospira interrogans serovars pomona, sejroe and hardjo by treating the organisms with 1.0M NaC1 followed by 0.04% sodium dodecyl sulfate (SDS). Sodium dodecyl sulfate was removed from the SDS-protein complexes by the extraction of dodecyl sulfate anions as ion pairs with triethylammonium cations into an organic solvent. The outer sheath antigen was recovered from the organic solvent as a precipitate and used as the source of leptospiral enzyme-linked immunosorbent assay (ELISA) antigen. Utilizing this antigen, ELISA was adapted to detect bovine serum antibody to L. interrogans serovars pomona, sejroe and hardjo. The specificity of this assay in 344 bovine sera, which were negative in the microscopic agglutination test (MAT) for seven serovars, was 99.4%. In sera from 37 and 87 cattle which revealed MAT titers greater than or equal to 1:50 for L. interrogans serovars pomona and sejroe, the relative sensitivity of the test was 100%. The ELISA also showed a considerable degree of low level cross-reactivity with other serovars. Sixty-six (75.9%) out of 87 bovine sera which were MAT-positive (MAT titer of greater than or equal to 1:50) with serovars sejroe and hardjo only were ELISA positive with heterologous pomona antigen; 16 (43.2%) and six 16.2%) out of 37 bovine sera which were MAT positive MAT titer of greater than or equal to 1:50) with serovar pomona only were ELISA positive with heterologous sejroe and hardjo ELISA antigen respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of two Ureaplasma diversum strains on early pregnancy in heifers.

Two field isolates of Ureaplasma diversum spp. were used to infect heifers at the time of insemination in a preliminary study to observe the effect of infection on early pregnancy. M84-14c-1 was a field isolate from a bull's prepuce typed by immunofluorescence to be similar to U. diversum strain T-44 (Group C). M84-477c-4 was a field isolate from bovine semen typed by immunofluorescence to be similar to U. diversum strain T-288 (Group A). All three heifers infected with M84-477c-4 had a mild granular vulvitis at some time during the trial. None was pregnant when slaughtered 27 days after infection. The result of infection with M84-14c-1, a preputial isolate, was not consistent. One heifer had no infection and a normal pregnancy, one heifer was infected with an abnormal pregnancy, and one heifer was open but ureaplasmas were not detected until day 17 of the trial.     

Phylogenetic analysis of the erythrocytic Anaplasma species based on 16S rDNA and GroEL (HSP60) sequences of A. marginale,A. centrale,and A. ovis and the specific detection of A. centrale vaccine strain

Phenotypic criteria for the identification of erythrocytic ruminant Anaplasma species has relied on subjective identification methods such as host pathogenicity (virulence for cattle or sheep) and/or the location of Anaplasma inclusion bodies within the host's red cells. Sequence comparisons of new and available GenBank Accessions were investigated to elucidate the relationships among these closely related Anaplasma species. Twenty-one 16S rDNA and GroEL (HSP60) sequences from 13 Anaplasma marginale (South Africa, Namibia, Zimbabwe, Israel, USA, Australia and Uruguay), three A. centrale (South Africa and Japan), two A. ovis (USA and South Africa), and two unknown Anaplasma species isolated from wild ruminants (South Africa), were compared. 16S rDNA maximum-likelihood and distance trees separated all A. marginale (and the two wild ruminant isolates) from the two South African A. centrale (including original vaccine strain, Theiler, 1911). The Japanese A. centrale (Aomori) demonstrated the lowest sequence identity to the remaining erythrocytic Anaplasma species. A. ovis inter-species relationships could not be resolved through the 16S rDNA analyses, whereas strong bootstrap branch support is demonstrated in the GroEL distance tree using A. ovis OVI strain. All erythrocytic Anaplasma species and isolates were confirmed to belong to the same cluster showing strong branch support to Anaplasma (Ehrlichia) phagocytophilum with Ehrlichia (Cowdria) ruminantium and Rickettsia rickettsii serving as appropriate out-groups. Based on groEL sequences, a specific PCR method was developed which amplified A. centrale vaccine (Theiler, 1911) specifically. This study confirms the suitability of 16S rDNA sequences to define genera and demonstrates the usefulness of GroEL sequences for defining species of erythrocytic Anaplasma.     

Babesiosis and heartwater: threats without boundaries.

Suppose one of your clients from southern Florida starts talking about cattle egrets while you are vaccinating her cat. It seems she found a nearly dead egret near the cattle pen a few days ago, picked it up, and noticed a number of what looked like small ticks on the legs. Or, suppose you are called out to a small dairy in central Texas to look at some cows that are feverish and anemic. The first animal you examine has a few brown ticks attached just under the tail. Finally, perhaps you are looking at a lame tortoise for a reptile fancier, a new client, and find a large, colorful tick on a hind leg, well up under the shell. Ring any bells? Egrets are great hosts for the immature stages of Amblyomma ticks and have been captured and marked in the eastern Caribbean, then recaptured in the Florida Keys. Those cattle ticks in Texas might be acaricide-resistant Boophilus ticks that originated in Mexico. The Amblyomma tick on the tortoise could well have "hitch-hiked" all the way from South Africa. By now you remember that both Amblyomma and Boophilus ticks are efficient vectors of two tickborne diseases in this hemisphere, heartwater (in the case of Amblyomma) and babesiosis (transmitted by Boophilus ticks). Both of these diseases are exotic to the United States, and because our livestock are considered to be totally susceptible, an introduced infection could result in high initial death losses (approximately 70%); thus, both the ticks and the diseases pose immediate threats to the health and economic security of United States animal industries. Most importantly, you, whether as a small animal or large animal practitioner, are the first line of defense against such exotic diseases and their vectors.     

An ELISA for the diagnosis of Babesia ovis infection utilizing a synthetic, Babesia bovis-derived antigen

The development of an enzyme-linked immunosorbent assay (ELISA) for the detection of Babesia ovis antibodies is described. In an initial study, a crude Babesia bovis antigen and a synthetic B. bovis-derived antigen (designated 11C5) were used to screen 46 B. ovis-positive and 55 negative sheep sera. A 95% correlation between the two antigenic preparations was found with the positive sera; no negative sera gave positive reactions. The synthetic antigen was then used in the screening of 1466 sera collected from sheep from 18 regions of Turkey. A high incidence of B. ovis-positive reactions was found from all regions (60-80%) in sheep over 1 year old, while from two smaller samples the incidence in young sheep was much less (28 and 52%). This test is superior to existing ones because the synthetic antigen can be produced in a highly reproducible state, is specific and is stable over extended periods of time.     

Efficacy, safety, and residue evaluation of levamisole gel formulation in sows

Anthelmintic efficacy, safety, and residue studies were conducted in sows and gilts with a levamisole gel containing 11.5% levamisole HCl. In 12 sows and 12 gilts, 8 mg of levamisole HCl equivalent/kg of body weight orally was 100% (resinate) and 91.1% (gel) effective against 55-day-old Ascaris suum and 100% (gel) and 96.1% (resinate) effective against Oesophagostomum dentatum. In 20 sows given levamisole gel (8 mg of levamisole HCl/kg) orally just before breeding, 4 to 6 weeks after breeding, 4 to 6 weeks before farrowing, and just before farrowing, there were no adverse effects. Transient salivation was noticed in five sows after treatment. In 4 groups of 4 sows each given levamisole gel orally to provide 8, 24, 40, or 80 mg of levamisole HCl/kg, adverse clinical signs were not observed in sows treated with 8 mg/kg. Transient salivation was noticed in one sow given 24 mg/kg, two sows given 40 mg/kg, and four sows given 80 mg/kg. Multiple emesis and chomping occurred in one sow given 80 mg/kg. Levamisole residues in edible tissues from sows given 8 mg of levamisole gel/kg orally were less than 0.1 mg/kg of muscle and fat in sows killed on posttreatment day (PTD) 3 and less than 0.1 mg/kg of kidney in sows killed on PTD 5. Liver residues averaged 0.78 mg/kg in sows killed on PTD 3 and were reduced to 0.31 mg/kg in sows killed on PTD 5. The 99% upper tolerance limit with 95% confidence on the withdrawal time to assure levamisole residues of less than 0.10 mg/kg in liver tissue was 11 days.     

Calfhood Immunization Against An Experimental Parainfluenza and Pasteurella Challenge

An inactivated vaccine including Parainfluenza-3, PASTEURELLA MULTOCIDA and PASTEURELLA HEMOLYTICA stimulated good immunity in calves against an experimental shipping fever challenge. Calves were first vaccinated when 4 to 10 weeks old and revaccinated at weaning age. There were higher HI titers, lower temperatures, and less lung lesions recorded in the vaccinated group when compared to the control animals.     

Sequence variation at a microsatellite locus (XGWM261) in hexaploid wheat (Triticum aestivum) varieties

The wheat microsatellite XGWM261 is of interest to wheat breeders because of its linkage to a commercially significant reduced height gene (Rht8). Previous studies have indicated that there are three major alleles at the XGWM261 locus and that the majority (90%) of varieties are homozygous, generating PCR products of 192,174, or 165 bp. As a preliminary investigation of heterozygosity and sequence variation at the XGWM261 locus in Australian wheat varieties, we cloned and sequenced PCR products from 24 hexaploid varieties of significance in Australian breeding programmes. Three major alleles of 192, 174 and 164 bp were found, but a165 bp allele was not detected. Prior genotyping via electrophoretic methods had indicated that 2 of the 24 (8%) varieties were heterozygous. Our results indicate that 6 varieties (25%) carry 2 or more of the major alleles. It is not clear whether this results from heterozygosity within individual seeds, or from heterogeneity of breeding stocks. With respect to the microsatellite region itself, we found that the 174 bp and 164 bp alleles actually represent (CT)₁₁AG and (CT)₆AG motifs (respectively) rather than(CT)₁₂ and (CT)₇. This finding has diagnostic potential. A further 2 varieties also carry an interrupted (CT)_nCC(CT)_n microsatellite not previously recorded. It is unclear whether this represents a separate allelic lineage or is simply the result of replication error. This revised version was published online in July 2006 with corrections to the Cover Date.     

Variation in resistance of Mexican landraces of maize to maize weevil Sitophilus zeamais,in relation to taxonomic and biochemical parameters

Summary Accessions representing twenty eight landraces of maize were assessed for susceptibility to the maize weevil, Sitophilus zeamais in standardized resistance tests. Susceptibility parameters such as weight loss of grain, number of insect progeny produced, the Dobie index of susceptibility, and oviposition on grain were found to vary significantly by genotype, with exceptional resistance found in accessions representing the Naltel, Chapalote and Palomero landraces. As in improved genotypes, susceptibility was negatively correlated to phenolic and protein content of the variety tested but positively correlated to moisture content. A detailed analysis of the phenolics revealed the presence of diferulate which may contribute to mechanical resistance of the seed by cross-linking of cell wall hemicelluloses. A canonical discriminant analysis of the resistance data suggests that most of the five landrace groupings are significantly different. The ancient indigenous and prehistoric mestisos groupings are sources of resistant genotypes.     

Efficacy of chlorine dioxide for disease control on stored potatoes

The post-harvest application of chlorine dioxide (ClO₂) was evaluated as a disease suppressant for stored potatoes. Chlorine dioxide was prepared by acidifying a buffered sodium chlorite solution with a food grade acid.In vitro studies verified the effectiveness of C1O₂ at low concentrations (ED₅₀ = 2 to 122 ppm) againstErwinia carotovora (soft rot),Fusarium spp. (dry rot) andHelminthosporium solani (silver scurf). Evaluations of tubers inoculated withPhytophthora infestans (late blight) andFusarium spp. or infected withH. solani and then treated with ClO₂ either going into storage or through the humidification system resulted in a lack of disease suppression. Inconsistent performance of C1O₂ in storage appeared to be a result of several contributing factors. Chlorine dioxide concentrations varied greatly (up to six-fold), depending upon the method of activating and diluting sodium chlorite solutions. Chlorine dioxide is a gas soluble in water and, therefore, is easily released from solution (25% –75% loss) into the air when applied as an aqueous spray. Chlorine dioxide reacts quickly with the tuber and associated organic matter, thereby reducing the effectiveness. Applying higher than currently registered rates may be necessary to achieve measurable disease suppression.