Experimental abortion and the systemic immune response to "Haemophilus somnus" in cattle

Abstract

Haemophilus somnus" has been identified in the etiology of bovine abortion on the basis of the isolation of the organism from aborted fetal and placental tissues. To investigate the role of hematogenous dissemination of "H. somnus" in the pathogenesis of abortion and to monitor the humoral immune response to infection, 19 pregnant cows (gestation ages, 1.4 to 7 months) were challenged intravenously (11 cows) or intrabronchially (8 cows). Five cows challenged intravenously aborted, and one cow challenged intrabronchially resorbed her fetus. "H. somnus" was isolated in large numbers from aborted tissues, and placental lesions were similar to those reported in a field case of "H. somnus" abortion. Antibody titers in serum were measured by the microagglutination test (MAT) and by enzyme-linked immunosorbent assay (ELISA). A response to challenge was measured by MAT; it was also measured by ELISA within the immunoglobulin Gl (IgGl), IgG2, and IgM isotypes. On comparison of pre-and postchallenge antibody titers, the greatest and most persistent response was detected within the IgG2 isotype. Prechallenge antibody titers (measured by MAT and by IgG2 ELISA) were lower in animals that aborted than in normal calving animals, indicating that IgG2 antibody may have a role in limiting hematogenous dissemination of "H. somnus."

Histophilosis as a Natural Disease

“…Abortion due to H. somni is associated with necrotizing placentitis involving cotyledons and intercotyledonary placenta, combined with medial arteritis (van Dreumel and Kierstead 1975;Miller et al 1983a, b;Widders et al 1986). Embryonic loss has also been attributed to histophilosis (Ruegg et al 1988;Kaneene et al 1986a, b).…”

“…HE stain lesions may be sufficiently severe to be evident grossly. Systemic lesions vary in the fetus but, when present, include angiocentric meningoencephalitis with vasculitis and generalized vascular lesions consistent with bacterial septicemia and disseminated intravascular coagulation (Van Dreumel and Kierstead 1975;Miller et al 1983b;Widders et al 1986;Headley et al 2013Headley et al , 2015. There have been few recent morphological studies of the lesions associated with H. somni in the female reproductive tract and none using IHC.…”

Stimulation of P2X receptors enhances lipooligosaccharide-mediated apoptosis of endothelial cells

“…LOS was isolated from H. somnus strain 649 [35], as described previously [36]. Protein contamination was not detected in the LOS preparation, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver-staining.…”

Pregnancy Rate Following Post‐insemination Intrauterine Treatment of Endometritis in Dairy Cattle

“…In any case, these facts have to be considered at the time of intrauterine treatment, that the bovine uterus is an anaerobic environment, thus antibiotics chosen for this purpose must preserve its activity in the absence of oxygen (Hussain and Daniel, 1991). It was also documented that most antibiotics and chemicals depress activity of uterine neutrophils and interfere with the normal uterine defense mechanism (Widders et al, 1986). Therefore, the potential benefits of their use must be carefully weighed against their deleterious effects.…”