Perinatal immuno/inflammatory responses in the presence or absence of bovine fetal infection

peer-reviewedBackground It is known that the bovine fetus can mount an immune and inflammatory reaction to infection, but it is not known whether there is a contemporaneous maternal response. Nor is it known whether the response of calves which die perinatally, with or without infection, differs from that of live perinates. Hence, the objective of this study was to determine if acute phase reactant and immunoglobulin concentrations differed between calves (and their dams) in three groups: live calves (CC; n = 21) and dead calves with (PM INF+; n = 22) or without (PM INF-; n = 89) in utero infection. In calf plasma, serum amyloid A, haptoglobin, immunoglobulins M, G1 and G2 and interleukin-6 were measured. In dam serum, SAA and Hp was measured and in amniotic and abomasal fluid, IL-6 was measured. Results Live calves had higher plasma concentrations of SAA and IL-6 than dead calves with (PM INF+) or without (PM INF-) in utero infection. Calves in the PM INF-, but not PM INF+ group, had higher Hp concentrations than calves in the CC group. Calves in the PM INF+ group had higher IgG1 concentrations than calves in the PM INF- and CC groups. Except for higher IgG1 and IgG2 concentrations, biomarker values did not differ significantly between dead calves with or without in utero infection. Live calves had higher IL-6 concentrations in abomasal fluid compared to PM INF- calves. There were no significant differences in blood biomarker concentrations between dams of the three groups of calves. Amniotic fluid IL-6 concentrations were higher from the dams of control calves than the dams of uninfected calves. Conclusions Differences in biomarkers (higher Hp and IgG1; lower SAA and IL-6) between perinatal mortalities and live perinates probably reflect differences between these two groups in age at sampling (SAA and IL-6) and in utero infection (IgG1). Out of the six analytes measured in calves, only IgG1 and IgG2 were biomarkers of (chronic) in utero infection

Immune and inflammatory biomarkers in cases of bovine perinatal mortality with and without infection in utero

peer-reviewedThe objective of this study was to compare acute-phase protein [serum amyloid A (SAA) and haptoglobin (Hp)] and immunoglobulin G1 and M concentrations in blood plasma of cases of bovine perinatal mortality due to infection in utero or traumotocia and in unexplained cases. Plasma samples were collected from 110 stillborn calves with bacterial infection (INF_B, n = 16), with viral or parasitic infection (INF_V/P, n = 31) during pregnancy, with lesions of fatal traumotocia (TRAUM, n = 22), and from unexplained deaths (UNEXPL, n = 41). Plasma immunoglobulin and SAA concentrations were measured by ELISA, and Hp concentrations were measured by the guaiacol method and ELISA. Concentrations of SAA in the INF_B group were higher than in the UNEXPL group and tended to be higher than in the INF_V/P group. A reference range (0–29 mg/L) was established for SAA in stillborn calves. Concentrations of Hp tended to be higher in the INF_B group compared with INF_V/P group. Concentrations of IgM tended to be higher in the INF_B group compared with the TRAUM and INF_V/P groups. Concentrations of IgG1 were numerically, but not significantly, higher in the INF_V/P and INF_B groups compared with the other groups. The results demonstrate upregulation of immune and inflammatory responses in stillborn calves exposed to bacterial infection in utero. The immune-inflammatory parameters did not differ between calves with viral or parasitic infections and traumotocia. These immune-inflammatory profiles did not contribute to the diagnosis of unexplained stillbirth. This is the first report of an elevated acute phase protein response in stillborn calves. Measurement of SAA and IgM concentrations may be used in the diagnosis of bacterial infections in stillborn calves

Infection exposure, detection and causes of death in perinatal mortalities in Polish dairy herds

peer-reviewedThe objective of this study was to determine the prevalence and types of infections in perinatal mortality (PM) cases from Polish dairy farms and the relevance of the presence of infection to the cause of death. This prospective longitudinal study was carried out on 121 PM and 21 control calves with a gestation of ≥260 days. Six control calves were euthanized and examined using the same protocol as for PM calves. Material was collected over a 20-month period between November 2013 and June 2015. The PM and control calves were collected from 29 to 5 herds, respectively. Blood samples from calves were tested for antibodies to Neospora caninum, glycoprotein B of BoHV-1, BVDV and SBV using ELISAs and Leptospira hardjo and Leptospira pomona with the microscopic agglutination test. Brain and kidney samples from all PM and six euthanized control calves were tested using real time PCR to detect Neospora caninum, pathogenic Leptospira spp., BoHV-1 and SBV; brain was examined histopathologically for detection of N. caninum cysts. Samples from eight inner organs from all PM and six control calves were cultured aerobically, anaerobically and microaerobically. Ear samples from all PM and control calves were tested for BVDV using an antigen ELISA. In total, 21.5% of PM calves were infected (antigen and/or antibody-positive) in utero; none of the control calves were infected. Direct evidence of infection (culture, Ag-ELISA, PCR, histopathology) was detected in 9.1% of PM calves. Gestation length in infected singletons was shorter than in uninfected singletons (274 ± 8 vs. 279 ± 7 days; P < 0.01). The odds ratio for diagnosis of infection in single pregnancies ≤275 days was 3.75 (95% CI:1.2–12.1), (P < 0.05). Infection was the cause of death in 10% of calves. The most common infections detected in these Polish PM calves were parasitic (11.6% of PM cases), viral (7.4%) and bacterial (5%). This study demonstrated that indirect evidence of infection is detected more frequently than direct, coinfection is rare, infection is rarely accompanied by gross lesions and is rarely a cause of death in cases of PM

Role of Infection and Immunity in Bovine Perinatal Mortality: Part 2. Fetomaternal Response to Infection and Novel Diagnostic Perspectives

Bovine perinatal mortality due to infection may result either from the direct effects of intrauterine infection and/or the fetal response to such infection, leading to the fetal inflammatory response syndrome (FIRS). Both intrauterine infection and FIRS, which causes multi-organ damage and involution of immune organs, compromise fetal survivability, sometimes fatally. Organ injury associated with FIRS may, in addition to causing fetal mortality, irreversibly compromise extrauterine adaptation of the neonate, a recognized problem in human fetuses. Diagnosis of intrauterine infection and of FIRS requires related, but independent analytical approaches. In addition to detection of pathogens, the immune and inflammatory responses of the bovine fetus may be utilized to diagnose intrauterine infection. This can be done by detection of specific changes in internal organs and the measurement of antibodies and/or elements of the acute phase reaction. Currently our ability to diagnose FIRS in bovine fetuses and neonates is limited to research studies. This review focuses on both the fetomaternal response to infection and diagnostic methods which rely on the response of the fetus to infection and inflammatory changes, as well other methods which may improve diagnosis of intrauterine infection in cases of bovine perinatal mortality