Use of real-time quantitative reverse transcription polymerase chain reaction for the detection of African horse sickness virus replication in Culicoides imicola

Despite its important role as vector for African horse sickness virus (AHSV), very little information is available on the dissemination of this virus in Culicoides (Avaritia) imicola Kieffer (Diptera: Ceratopogonidae). This study reports on the applicability of a real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) to detect AHSV in dissected midges. A total of 96 midges were fed on AHSV-infected blood, after which one test group was dissected into head/thorax and abdomen segments immediately after feeding and the other only after 10 days of incubation. The majority of the midges (96%) ingested the virus successfully and there was no significant difference between the virus concentration in the heads/thoraxes and the abdomens immediately after feeding. After incubation, virus was detected in 51% of the midges and it was confined to the abdomen in the majority of these. The fact that virus was detected only in the heads/thoraxes of four Culicoides midges after incubation suggests the presence of a mesenteronal escape barrier. Replication in the salivary glands was not shown. An increase of the mean virus concentration in the abdomen after incubation indicates localised viral replication. The real-time RT-qPCR is recommended for further studies investigating the replication and dissemination of AHSV in Culicoides midges

Evaluating African horse sickness virus in horses and field-caught Culicoides biting midges on the East Rand, Gauteng Province, South Africa

A prospective study was undertaken during 2013 and 2014, to determine the prevalence of African horse sickness virus (AHSV) in Culicoides midges and the incidence of infection caused by the virus in 28 vaccinated resident horses on two equine establishments on the East Rand, Gauteng Province, South Africa. Field caught Culicoides midges together with whole blood samples from participating horses were collected every two weeks at each establishment. Culicoides midges and blood samples were tested for the presence of AHSV RNA by real-time quantitative reverse transcription polymerase chain reaction. Nine immunised horses became infected with AHSV during the study period, although infections were subclinical. African horse sickness virus was also identified from a field-collected midge pool. The observations recapitulate previously published data in another setting, where further investigation is warranted to determine what role subclinical infection plays in the diseases epidemiology

Complete genome sequences of five bluetongue virus (BTV) vaccine strains from a commercial live attenuated vaccine, a BTV-4 field strain from South Africa, and a reassortant strain isolated from experimentally vaccinated cattle

This is a report of the complete genome sequences of plaque-selected isolates of each of the five virus strains included in a South African commercial trivalent bluetongue virus (BTV) attenuated live virus vaccine, a BTV-4 field strain isolated from Rustenburg, South Africa, in 2011, and a bluetongue reassortant (bluetongue virus 4 strain 4/O. aries-tc/ZAF/11/OBP-115) isolated from experimentally vaccinated cattle. Full-genome sequencing and phylogenetic analyses show that the bluetongue virus 9 strain 9/B. taurus-tc/ZAF/15/Onderstepoort_B02b is a reassortant virus containing segments from both BTV-9 and BTV-8

Shotgun genome sequence and population diversity of Mannheimia haemolytica isolates from sheep in South Africa

Respiratory disease caused by Mannheimia haemolytica is a major economic and welfare concern in the cattle and small stock industry worldwide. Disease occurs due to the interaction of numerous factors, including weaning stress, shipment, inclement weather, and overcrowding coupled with viral and bacterial infections. The whole genome of M. haemolytica strain Mh10517 was analyzed using an Illumina MiSeq high throughput sequencing platform. The genome size is 2.67 Mb with 2,879 predicted gene sequences. The molecular evolution and relatedness of M. haemolytica was investigated using nucleotide sequence data of seven housekeeping gene fragments from 21 ovine isolates. MEGA version 7.0 genomic workbench was used for alignment and analysis of the nucleotide data sets. For each gene fragment, the sequences were compared and isolates with identical sequences were assigned the same allele number. Results suggested that the 21 isolates belonged to six sequence types (ST) and ST 28 accounted for 33% of the isolates. Neighbour joining method was used to produce dendograms based on the concatenated sequences of the seven loci in multilocus allelic profile. There was significant variation between the number of synonymous and non-synonymous substitutions between each sequence pairs (p=0.018) based on results from the Fisher’s exact test of neutrality of sequence pairs. These preliminary data show substantial sequence variations and this supports the hypothesis that ovine isolates of M. haemolytica are more diverse that what has been reported for isolates from other species. These results will advance studies on various aspects of the biology of M. haemolytica in Africa, and the world at large.Poster presented at the University of Pretoria, Faculty of Veterinary Science Faculty Day, September 07, 2017, Pretoria, South Africa.Includes bibliographical referencesab201

Complete Genome Sequences of Virus Strains Isolated from Bottle A of the South African Live Attenuated Bluetongue Virus Vaccine

This is a report of the complete genome sequences of plaque-selected isolates of five virus strains included in bottle A of the South African Onderstepoort Biological Products commercial live attenuated bluetongue virus vaccine

Occurrence of African horse sickness in a domestic dog without apparent ingestion of horse meat

This is the first case of African horse sickness (AHS) in a dog where there was no apparent ingestion of horse meat. Significantly, the dog was part of a colony that resides in a Good Clinical Practice and Good Laboratory Practice accredited facility where complete history, weather and feeding records are maintained. The dog died after a week-long illness despite therapy. The principal post-mortem findings were severe hydrothorax and pulmonary consolidation (red hepatisation of the lungs). Histopathology revealed severe oedema and congestion of the lungs, hyaline degeneration of the myocardium and congestion of the liver sinusoids. Immunohistochemistry detected AHS-positive staining granules in the myocardium, whilst a real-time reverse transcription quantitative Polymerase chain reaction assay of tissue samples was strongly positive for African horse sickness virus nucleic acid. Other dogs on the property showed a 43% seroconversion rate to AHS.The National Veterinary Clinicians Group of the South African Veterinary Associationhttp://www.jsava.co.zaam2014ab201

A PCR-based screening program to assess the prevalence of Taylorella equigenitalis in breeding stallions in South Africa

The first outbreak of Contagious Equine Metritis (CEM) due to Taylorella equigenitalis in South Africa was reported to the OIE in May 2011 subsequent to importation of a stallion, the index case. Two additional positive stallions were identified on an initial trace-back. The outbreak-response prompted determination of the national prevalence and distribution of CEM. A nation-wide PCR-based screening of all breeding stallions motivated by a previous outbreak report [1] was implemented via a mandatory CEM-negative clearance certificate prior to use for natural breeding or semen collection. Compliance from breeders was facilitated by developing a web-based system providing an easily-accessed, rapid and costeffective sampling, testing and reporting process on www.cemsa.co.za. A submission form, information, a breed-indexed list of stallions achieving CEM-clearance and a method for obtaining and submitting two sets of swabs (with an interval > 7d) from the external genitalia were accessible on the website. A duplex PCR was chosen as the assay method due to potential for submission of samples with minimal restrictions on transit time and temperature criteria and rapid, high throughput, cost-effi-ciency and reported sensitivity *1,2+. A clearance certificate was issued via the website after negative results from both sets of samples.http://www.journals.elsevier.com/journal-of-equine-veterinary-sciencehb2016Equine Research Centr

A programme theory for liaison mental health services in England

Background: Mechanisms by which liaison mental health services (LMHS) may bring about improved patient and organisational outcomes are poorly understood. A small number of logic models have been developed, but they fail to capture the complexity of clinical practice. Method: We synthesised data from a variety of sources including a large national survey, 73 in-depth interviews with acute and liaison staff working in hospitals with different types of liaison mental health services, and relevant local, national and international literature. We generated logic models for two common performance indicators used to assess organisational outcomes for LMHS: response times in the emergency department and hospital length of stay for people with mental health problems. Results: We identified 8 areas of complexity that influence performance, and 6 trade-offs which drove the models in different directions depending upon the balance of the trade-off. The logic models we developed could only be captured by consideration of more than one pass through the system, the complexity in which they operated, and the trade-offs that occurred. Conclusions: Our findings are important for commissioners of liaison services. Reliance on simple target setting may result in services that are unbalanced and not patient-centred. Targets need to be reviewed on a regular basis, together with other data that reflect the wider impact of the service, and any external changes in the system that affect the performance of LMHS, which are beyond their control