Experimental infection of the red-backed vole (Clethrionomys gapperi) with Borrelia burgdorferi.

Red-backed voles (Clethrionomys gapperi) were live trapped in northern St. Louis County, Minnesota (USA), in late September and October 1988 and experimentally inoculated with Borrelia burgdorferi. Spirochetes were isolated from most animals 14 and 28 days following inoculation. Thus, red-backed voles exposed to B. burgdorferi were susceptible to infection and could be a reservoir host, along with chipmunks (Tamias striatus) and other small rodents, in areas where white-footed mouse (Peromyscus leucopus) populations are low. No evidence of clinical disease was noted in any infected voles.

Seroprevalence of Lyme disease in gray wolves from Minnesota and Wisconsin.

To determine the seroprevalence of Lyme disease in gray wolves (Canis lupus) from various counties of Minnesota and Wisconsin (USA), 589 serum samples were collected from 528 wolves from 1972 to 1989. An indirect fluorescent antibody (IFA) test was used to detect the presence of antibodies against Borrelia burgdorferi. Titers of greater than or equal to 1:100 were considered positive. Results were confirmed by testing a few selected sera by Western blotting. Of the 589 sera tested, 15 (3%) had IFA titers of greater than or equal to 1:100. Three of the positive samples were collected from Douglas County in Wisconsin and twelve were from Minnesota counties. This study indicates that wolves are exposed to B. burgdorferi and are susceptible to Lyme disease.

110-kilodalton recombinant protein which is immunoreactive with sera from humans, dogs, and horses with Lyme borreliosis.

EcoRI-digested DNA from Borrelia burgdorferi was ligated into the dephosphorylated vector pWR590 and transformed into Escherichia coli DH5 alpha. When the gene library was screened, 20 clones reacted with pooled dog sera with high titers (immunofluorescent antibody titer, greater than or equal to 1,280) to this spirochete. One clone expressed a 110-kDa antigen that reacted strongly with the high-titered pooled sera from dogs with Lyme borreliosis and serum from goats immunized with B. burgdorferi. The 110-kDa protein was serum from goats immunized with B. burgdorferi. The 110-kDa protein was expressed with and without isopropyl-beta-D-thiogalactosidase, indicating the protein is not a fusion protein with beta-galactosidase. Monospecific antisera to the 110-kDa antigen recognized a 75-kDa Borrelia protein. Of the sera that reacted with B. burgdorferi by immunoblotting; 57, 100, and 83% of human, dog, and horse serum samples, respectively, reacted with the 110-kDa protein. Sera from individuals that tested negative with a B. burgdorferi lysate with immunoblotting showed no reaction with the 110-kDa protein. The 110-kDa antigen appears to be useful for the diagnosis of Lyme borreliosis.

Ixodes dammini: occurrence and prevalence of infection with Borrelia spp. in Minnesota.

The distribution of Ixodes dammini in Minnesota was studied by collecting adult ticks from hunting dogs during the grouse seasons in September and October of 1985 and 1986. The tick was most frequently found in the east-central part of the state. Borrelia spp. were observed by immunofluorescence in 10% of the ticks. The locations where ticks were found coincide with the primary endemic areas for Lyme disease in the state.

Purification and characterization of the 1q subcomponent of canine complement and its use in the 125I-C1q binding assay for detection of immune complexes.

The complement subcomponent, C1q, was isolated from serum obtained from clinically normal dogs, using a rapid 2-step process involving affinity chromatography. Yield of C1q ranged from 8 to 10 mg/L of serum. Hemolytically active C1q had 3 protein bands after sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions and formed a single line of identity with rabbit anti-canine C1q. The amino acid composition of canine C1q was similar to that of human C1q and contained a high percentage of glycine. Isolated canine C1q was iodinated, and the fluid-phase binding assay was used to detect circulating immune complexes in dogs with systemic lupus erythematosus and rheumatoid arthritis.

Isolation of the Lyme disease spirochete from mammals in Minnesota.

Lyme disease spirochetes were isolated from the kidneys of two Peromyscus spp. trapped in Minnesota in September and October 1983. No spirochetes were isolated from white-tailed deer (Odocoileus virginianus), red backed voles (Clethrionomys gapperi), or shrews (Sorexy cinereus and Blarina brevicauda). This is the first report of the isolation of the Lyme disease spirochete from the midwestern United States and isolations from these animals, which were free of ticks, suggest that the Lyme disease spirochete may persist in animal organs for months.

Effect of antimicrobial agents and corticosteroids on bovine polymorphonuclear leukocyte chemotaxis.

The effect of certain antimicrobial agents and corticosteroids on bovine polymorphonuclear leukocyte chemotaxis was investigated. Peripheral blood was fractioned by density-gradient centrifugation, using Ficoll-Hypaque. The chemotactic assay was performed in modified Boyden chambers, using Micropore filters, and the chemotactic response was measured by the leading-front technique. Tetracyclines, streptomycin, and penicillin had no effect on chemotaxis at concentrations normally achieved in blood during systemic treatment. However, higher concentrations that were achievable with local therapy, such as intramammary injection or topical application, inhibited the chemotactic response. This inhibition was eliminated by serum. Dexamethasone stimulated polymorphonuclear leukocyte chemotaxis with the effect being manifested after the cells were incubated with the drug for 3 hours. Hydrocortisone caused slight inhibition of chemotaxis, whereas prednisone and prednisolone had no effect.

Enhancement of the chemotactic response of bovine polymorphonuclear leukocytes by levamisole.

The effects of levamisole on random migration, chemotaxis, phagocytosis, and intracellular killing by bovine polymorphonuclear leukocytes (PMN) were investigated. Chemotactic assays were performed, using Micropore filters in modified Boyden chambers. Phagocytosis and intracellular killing of Escherichia coli were analyzed by standard viable bacterial counts. Results indicated that levamisole enhanced the chemotactic response of PMN at concentrations ranging from 10(-4) to 5 x 10(-3)M. Phagocytes collected from cows at 90 minutes after IM injection of levamisole also showed enhanced random migration and chemotaxis. Freshly prepared serum was shown to enhance the levamisole-induced stimulation of chemotaxis. Levamisole had no effect on phagocytosis or intracellular killing of E coli by bovine PMN.

Microbiological quality of protein feed supplements produced by rendering plants.

Samples of protein feed supplements produced by rendering plants were examined for salmonellae, total aerobic bacterial counts, coliform counts, and enterococci. Isolations of salmonellae were more frequent from products with high counts; however, 6% of the samples with total counts of less than 1,000 per gram and 14% of the samples with coliform counts of less than 1 per gram contained salmonellae. Serotypes of Escherichia coli which have been associated with disease in domestic animals and poultry were also isolated from products. Although the distribution of serotypes of salmonellae isolated from environmental swabs and flies was similar to that isolated from products, the isolation of several serotypes from flies which had not been isolated in plants suggested that flies may be a potential source of contamination.