Standardization of a SNP panel for parentage verification and identification in the domestic cat (Felis silvestris catus).

The domestic cat (Felis silvestris catus) is a valued companion animal throughout the world. Over 60 different cat breeds are accepted for competition by the cat fancy registries in different countries. Genetic markers, including short tandem repeats and SNPs, are available to evaluate and manage levels of inbreeding and genetic diversity, population and breed structure relationships, and individual identification for forensic and registration purposes. The International Society of Animal Genetics (ISAG) hosts the Applied Genetics in Companion Animals Workshop, which supports the standardization of genetic marker panels and genotyping for the identification of cats via comparison testing. SNP panels have been in development for many species, including the domestic cat. An ISAG approved core panel of SNPs for use in cat identification and parentage analyses is presented. SNPs (n = 121) were evaluated by different university-based and commercial laboratories using 20 DNA samples as part of the ISAG comparison testing procedures. Different SNP genotyping technologies were examined, including DNA arrays, genotyping-by-sequencing and mass spectroscopy, to select a robust and efficient panel of 101 SNPs as the ISAG core panel for cats. The SNPs are distributed across all chromosomes including two on the X chromosome and an XY pseudo-autosomal sexing marker (zinc-finger XY; ZFXY). A population study demonstrated that the markers have an average polymorphic information content of 0.354 and a power of exclusion greater than 0.9999. The SNP panel should keep testing affordable while also allowing for the development of additional panels to monitor health, phenotypic traits, hybrid cats and highly inbred cats.

Short communication: performance of a blocking antibody ELISA bulk-tank milk test for detection of dairy sheep flocks exposed to border disease virus.

The aim of this study was to investigate the test characteristics of a blocking antibody ELISA applied to bulk-tank milk (BTM) samples for the detection of dairy sheep flocks positive for antibodies to border disease virus. In 161 flocks recruited in 2009 and 2010, the antibody inhibition percentage (AIP) in BTM was compared with the prevalence estimate of antibody-positive ewes obtained from an age-representative sample of 45 milking ewes. A strong negative exponential relationship (R(2)=0.89) was found between AIP in BTM and seroprevalence level. Using receiver operating characteristic analysis, the best AIP decision threshold in BTM to discriminate between low (<10%) and high (≥10%) antibody-positive flocks was 65%. Diagnostic performance estimates based on observed seroprevalence levels and Monte Carlo simulations showed that this threshold value was associated with high sensitivity and specificity (91.9±5.5% and 95.9±1.6%, respectively), whereas the 80% decision threshold recommended in dairy cows yielded lower specificity (83.6±2.0%). Results obtained from the same flocks during 2 subsequent milking campaigns showed that the 65% AIP cut-off value was associated with fewer false-positive results and is preferred. Testing of BTM samples could be a powerful tool in inferring border disease virus seroprevalence in a flock and in Pestivirus control schemes in dairy sheep flocks.

First outbreak of Trypanosoma evansi in camels in metropolitan France.

The first outbreak of trypanosomosis caused by Trypanosoma evansi in camels in France was reported on a farm in the Aveyron Department. Five camels were imported from the Canary Islands to the farm in early July 2006, and trypanosomes were observed on a stained blood smear from one of them, which died in October. On further investigations, trypanosomes were observed in the blood of five camels, three of them indigenous to the farm and two that had been imported. On the basis of microscopical examination (morphological criteria and measurements) and serological results based on the card agglutination T evansi test and PCR typing, the parasites were identified as T evansi. After treatment with melarsomine, the infected camels rapidly became negative by parasitological tests and were negative two to four months later by serological tests. The parasite was probably transmitted by tabanids and Stomoxys calcitrans, which were abundant in July to September 2006. No parasites were observed in other animals on the farm or on neighbouring farms, but some of the sheep on these farms were positive by PCR or serology.