Antibody and cellular immune responses of naïve mares to repeated vaccination with an inactivated equine herpesvirus vaccine.

Equine herpesvirus type 1 (EHV-1) continues to cause severe outbreaks of abortions or myeloencephalopathy in horses despite widely used vaccination. The aim of this work was to determine the effects of frequent vaccination with an inactivated EHV vaccine on immune development in horses. Fifteen EHV-1 naïve mares were vaccinated a total of 5 times over a period of 8 months with intervals of 20, 60, 90 and 60 days between vaccine administrations. Total antibody and antibody isotype responses were evaluated with a new sensitive EHV-1 Multiplex assay to glycoprotein C (gC) and gD for up to 14 months after initial vaccination. Antibodies peaked after the first two vaccine doses and then declined despite a third administration of the vaccine. The fourth vaccine dose was given at 6 months and the gC and gD antibody titers increased again. Mixed responses with increasing gC but decreasing gD antibody values were observed after the fifth vaccination at 8 months. IgG4/7 isotype responses mimicked the total Ig antibody production to vaccination most closely. Vaccination also induced short-lasting IgG1 antibodies to gC, but not to gD. EHV-1-specific cellular immunity induced by vaccination developed slower than antibodies, was dominated by IFN-γ producing T-helper 1 (Th1) cells, and was significantly increased compared to pre-vaccination values after administration of 3 vaccine doses. Decreased IFN-γ production and reduced Th1-cell induction were also observed after the second and fourth vaccination. Overall, repeated EHV vaccine administration did not always result in increasing immunity. The adverse effects on antibody and cellular immunity that were observed here when the EHV vaccine was given in short intervals might in part explain why EHV-1 outbreaks are observed worldwide despite widely used vaccination. The findings warrant further evaluation of immune responses to EHV vaccines to optimize vaccination protocols for different vaccines and horse groups at risk.

Antibodies to OspC, OspF and C6 antigens as indicators for infection with Borrelia burgdorferi in horses.

REASONS FOR PERFORMING STUDY: Lyme disease is caused by Borrelia burgdorferi, which is transmitted by infected ticks (Ixodes spp.). Reports on Lyme disease in horses have increased in recent years. Nevertheless, the diagnosis of Lyme disease in horses is still challenging owing to its vague clinical presentation and the limitations of diagnostic tests. OBJECTIVES: This study used a new serological Lyme multiplex assay to examine antibody responses to 3 antigens of B. burgdorferi, outer surface protein (Osp) C, OspF and C6, and to verify their use as markers for early and late infection stages in horses. METHODS: Multiplex analysis of antibodies to OspC, OspF and C6 in equine patient sera (n = 191) was performed. A subset of the sera (n = 90) was also tested using a commercial C6-based Lyme test. RESULTS: Antibodies to OspF and C6 highly correlate as reliable markers of infection with B. burgdorferi in horses. Antibodies to OspC, which have been confirmed as early infection markers in man and dogs, were only detected in some patient sera, suggesting that OspC antibodies are indicators of early infection in horses. Commercial C6 testing identified most infected horses but also resulted in false positive and false negative interpretations. CONCLUSIONS: Serological multiplex testing is a rapid and quantitative diagnostic method to confirm infection with B. burgdorferi and to identify the stage of infection. In horses with risk of exposure and clinical signs, multiplex testing supports the diagnosis of Lyme disease. POTENTIAL RELEVANCE: Antimicrobial treatment of B. burgdorferi is time sensitive. Treatment success decreases with time of persistent infection, while the risk of developing chronic disease increases. The ability to identify early infection with B. burgdorferi provides practitioners and clinicians with a tool to improve the diagnosis of equine Lyme disease and make treatment decisions.

Detection of equine herpesvirus-1 in nasal swabs of horses by quantitative real-time PCR.

BACKGROUND: Early identification of inhalation-transmitted equine herpesvirus type 1 (EHV-1) infections has been facilitated by the availability of a number of real-time quantitative PCR (qPCR) tests. A direct comparison between nasal swab qPCR and traditional virus isolation (VI) requires a method for normalizing the qPCR samples and controlling for PCR inhibitors present in some clinical samples. OBJECTIVES: To quantify EHV-1 shedding in viral swabs using an internal control and to compare fast qPCR to VI for the detection of EHV-1 in nasal swabs from horses. ANIMALS: Fifteen horses experimentally infected with EHV-1. METHODS: Experimental study: Nasal swab samples were collected daily after experimental infection for up to 21 days. VI was performed by conventional methods. The DNA was prepared for qPCR with the addition of a known quantity DNA of Marek's disease virus as an internal control. qPCR was performed. RESULTS: The qPCR method detected virus up to day 21 after challenge, whereas VI detected virus only to day 5. The median Kaplan-Meier estimates for EHV-1 detection were 12 days for qPCR and 2 days for VI (P< .0001). When compared with VI, the sensitivity and specificity of qPCR were 97 (95% CI: 86-100) and 27% (95% CI: 20-35). CONCLUSIONS AND CLINICAL IMPORTANCE: We conclude that fast qPCR of nasal swab samples should be chosen for diagnosis and monitoring of herpesvirus-induced disease in horses. Recommended reference ranges of C(T) values are provided as well as justification of a minimum 10-day quarantine period.

Trauma and posttraumatic stress disorder in severe mental illness.

This research assessed the lifetime prevalence of traumatic events and current posttraumatic stress disorder (PTSD) in 275 patients with severe mental illness (e.g., schizophrenia and bipolar disorder) receiving public mental health services in Concord and Manchester, New Hampshire, and Baltimore, Maryland. Lifetime exposure to traumatic events was high, with 98% of the sample reporting exposure to at least 1 traumatic event. The rate of PTSD in our sample was 43%, but only 3 of 119 patients with PTSD (2%) had this diagnosis in their charts. PTSD was predicted most strongly by the number of different types of trauma, followed by childhood sexual abuse. The findings suggest that PTSD is a common comorbid disorder in severe mental illness that is frequently overlooked in mental health settings.