PubMed · 4785457
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
E E Vella, D Goode. 1973. Brucellosis.. https://doi.org/10.1016/0035-9203(73)90076-x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
A comparison was made of the agglutination and lysis of three strains of Trypanosoma cruzi in gut extracts and hemolymph of Rhodnius prolixus and the results obtained were correlated with the success or failure of the parasite strain to infect the digestive tube or to survive in the hemocel after inoculation. Both T. cruzi strains Dm28c and Cl urine 35 days after feeding with parasites. Concomitantly, both of these strains were agglutinated but not lysed by the crop extracts. In contrast, T. cruzi Y strain parasites rapidly disappeared from the gut and showed no agglutination, but some lysis, in the crop extract. Following inoculation into the hemocel, only the Cl strain survived at high levels and was also the only strain agglutinated significantly in the hemolymph. Both Dm28c and Y strains rapidly disappeared from the hemocel with the former parasite being removed more slowly than the latter, probably due to clearance by the cellular defenses. The rapid clearance of the Y strain was correlated with the presence of a high titer lysin in the hemolymph. Subsequent experiments using FITC-labeled lectins and FACS to probe the carbohydrates on the parasite surfaces showed significant differences between the three strains. Thus, only Dm28c was stained strongly by Arachis hypogea (PNA) lectin, indicating the presence of galactose/N-acetylgalactosamine residues, and Dm28c and Y strains by Phytolacca lectin for N-acetyl glucosamine moieties. Finally, the fact that, in contrast to Dm28c and Y, the Cl strain strongly interacted with Triticum vulgaris (WGA) but not with Phytolacca lectin may be due to the presence of N-acetyl neuraminic acid residues on these organisms. These surface carbohydrate differences may be correlated both to the behavior and agglutination variations between the three strains recorded in this work.
A seroepidemiological survey of Toxoplasma gondii infection in sheep and goats was conducted in the Madrid region of Spain. Sera were collected from 60 herds, for which farming management information and other relevant data for their characterization were also obtained through a questionnaire. The seroprevalence was 11.8% (64 out of 541), using the modified (2-mercaptoethanol) direct agglutination technique with a 1:64 cut-off titre. The relationship between seropositivity and the variables in the questionnaire was assessed by multivariate analysis. Four variables were found to be significantly associated with seroprevalence. Two of them, the presence of cats and a previous history of abortion outbreaks in the farm, were factors known to be linked with toxoplasmosis, indicating the validity of the serological data. Seropositivity was also related to a lack of replacements in the preceding year. Proximity to other farms appeared to be a protective factor negatively associated with seropositivity, probably because it was an indicator of proximity to an urban area and the availability of local sanitary facilities.
A study was conducted to determine whether an allergen that has been prepared from a mucoid strain of Brucella abortus triggers a serum antibody response that interferes with the interpretation of serologic tests results. Fifteen cattle seronegative for Brucella antigen were tested with the SDTH test several times. Blood samples were collected weekly and tested with the serum agglutination test and complement fixation test. Results show that some cattle tested seronegative after each of the SDTH tests while other cattle tested weakly positive with the serum agglutination test or the complement fixation test. All seropositive cattle tested seronegative 4-7 weeks after the last SDTH test indicating an antibody response of a transient nature. We conclude that serologic tests results indicating infection are reliable when recorded four weeks after a single SDTH test. If cattle are tested with the SDTH test several times an interval of seven weeks should be observed after the last test to ensure a reliable interpretation of the serologic test results.