No abstract

When faced with a substantial risk of natural exposure to EAV, it would appear to be safe to vaccinate healthy pregnant mares up to 3 months before foaling and during the immediate postpartum period. Vaccinating mares during the last 2 months of gestation was associated with a risk of abortion; this risk must be weighed against the much greater risk of widespread abortions in unprotected populations of pregnant mares naturally infected with EAV.

BackgroundEquine rhinitis viruses A and B (ERAV and ERBV) are common equine respiratory viruses belonging to the family Picornaviridae. Sero-surveillance studies have shown that these two viral infections are prevalent in many countries. Currently, the diagnosis of ERAV and ERBV infections in horses is mainly based on virus isolation (VI). However, the sensitivity of VI testing varies between laboratories due to inefficient viral growth in cell culture and lack of cytopathic effect. Therefore, the objective of this study was to develop molecular diagnostic assays (real-time RT-PCR [rRT-PCR] and conventional RT-PCR [cRT-PCR] assays) to detect and distinguish ERAV from ERBV without the inherent problems traditionally associated with laboratory diagnosis of these infections.ResultsThree rRT-PCR assays targeting the 5'-UTR of ERAV and ERBV were developed. One assay was specific for ERAV, with the two remaining assays specific for ERBV. Additionally, six cRT-PCR assays targeting the 5'-UTR and 3D polymerase regions of ERAV and ERBV were developed. Both rRT-PCR and cRT-PCR assays were evaluated using RNA extracted from 21 archived tissue culture fluid (TCF) samples previously confirmed to be positive for ERAV (n = 11) or ERBV (n = 10) with mono-specific rabbit antisera. The ERAV rRT-PCR and cRT-PCR assays could only detect ERAV isolates and not ERBV isolates. Similarly, the ERBV rRT-PCR and cRT-PCR assays could only detect ERBV isolates and not ERAV isolates. None of the rRT-PCR or cRT-PCR assays cross-reacted with any of the other common equine respiratory viruses. With the exception of one cRT-PCR assay, the detection limit of all of these assays was 1 plaque forming unit per ml (pfu/ml).ConclusionThe newly developed rRT-PCR and cRT-PCR assays provide improved diagnostic capability for the detection and differentiation of ERAV and ERBV. However, a larger number of clinical specimens will need to be tested before each assay is adequately validated for the detection of ERAV and/or ERBV in suspect cases of either viral infection.

been used to detect specific antibodies against the infections, but these assays are also restricted due to their antibody-detected limitation and/or potential cross-reactivity to other pathogens. For example, reading of IFAT results is very difficult to read results and not objective at borderline between positive and negative titers. Results of IFAT may also change not only with different origin of antigens, but also with different lots of FITC-conjugated anti-horse IgG antibody. Recently, new diagnostics such as immunochromatographic test (ICT) and loop-mediated isothermal amplification (LAMP) assay have been developed for the detection of B. caballi and/or T. equi infections. ICT has similar sensitivity to ELISA and is a rapid and simple method to detect antibodies [1]. LAMP assay can rapidly amplify DNA samples within one hour under an isothermal condition (at 60 to 65 C). LAMP has higher specificity and sensitivity than those of PCR [2]. Therefore, both ICT and LAMP are practical pen-side diagnostic methods for equine piroplasmosis. The objectives of this presentation are to review diagnostic methods and problems of the current diagnostic methods, to introduce newly developed diagnostics, and to discuss how these methods can contribute the strengthening of quarantine for equine piroplasmosis. References[1] Huang X, et al. Immunochromatographic test for simultaneous serodiagnosis of Babesia caballi and B. equi infections in horses. Clin Vaccine Immunol 2006;13:553-5. [2] Alhassan A, et al. Comparative evaluation of the sensitivity of LAMP, PCR and in vitro culture methods for the diagnosis of equine piroplasmosis.Equine rhinitis virus A and B (ERAV and ERBV) are common equine respiratory viruses belonging to the family Picornaviridae. There is evidence that these two viral infections are prevalent in countries in which sero-surveillance studies have been undertaken. Currently there is a lack of rapid and reliable diagnostic methods for virus detection and antibody determination. The sensitivity of virus isolation varies between laboratories and is confounded by difficulties in isolating virus from the urine of carrier horses. The objective of this study was to develop molecular diagnostic assays (real-time RT-PCR [rRT-PCR] and conventional RT-PCR [cRT-PCR] assays) capable of detecting and distinguishing ERAV from ERBV without the inherent problems associated with the current laboratory diagnosis of these infections. Three rRT-PCR assays targeting the 5'-UTR of ERAV and ERBV were developed. One assay was specific for ERAV, whereas the remaining two assays were specific for ERBV. In addition, six cRT-PCR assays targeting the 5'-UTR and 3D polymerase regions of ERAV and ERBV were also developed. RNA extracted from prototype strains of ERAV and ERBV as well as 21 archived tissue culture fluid samples which were previously determined to be positive by virus isolation for ERAV or ERBV with mono-specific rabbit antisera were used to evaluate the sensitivity and specificity of these assays. Using serial decimal dilu...

The ability to recover muscle size after disuse is attenuated at old age. We hypothesized that anabolic and catabolic pathways were altered with aging thereby inhibiting the regrowth response. Male Fisher344/Brown Norway rats at 6 (young) and 32 (old) months of age were divided into 3 groups: ambulatory controls, hindlimb suspended (HS) for 2 weeks and HS followed by two weeks reloading (RE). Soleus muscle weight and muscle fiber cross sectional area decreased with HS and recovered to control in young, but not old rats. mRNA abundance of protein degradation marker MAFbx and autophagy markers Atg5 and Atg7 increased with HS and were restored to control with RE in soleus muscle of young and old rats. Similarly, phosphorylated GSK3β was decreased with atrophy induced by HS and returned to control upon reloading in both ages. In contrast, no changes in phsophorylated p70s6kinase were observed at either age. We conclude that changes in anabolic and catabolic pathways associated with alterations in muscle size are similar in soleus muscles of young and old rats, suggesting that factors external to muscle may play a role in the attenuated muscle regrowth response in the aged. Funding NIH AG28925