Bluetongue virus-infected adult midges surviving winter may have been responsible for the re-emergence of bluetongue this year in northern Europe.

In a paper just published in the Veterinary Record*, Anthony Wilson and colleagues of the Institute for Animal Health's (IAH) Pirbright Laboratory have presented evidence to support the view that the reappearance of bluetongue in northern Europe this year could have been
caused by adult midges surviving from the previous year.

The question as to whether this second season of bluetongue was due to re-introduction of the BTV-8, survival of the virus in some animals that had been infected in 2006 or in larval forms of the midge, or in adult midges that survived the winter, is not known, and is addressed in this
Veterinary Record paper.

Anthony Wilson said: "The ability of bluetongue virus to re-emerge in temperate areas after absences of several months has been a source of discussion for years. Other researchers have proposed complex and unusual mechanisms. Our work suggests that simpler mechanisms may also have a major role to play."

Below 15 degrees C there is virtually no replication of the virus in a midge. However, at low temperatures the virus remains dormant in the midges and the midges themselves can survive for much longer than at summer temperatures.

Bluetongue virus came to northern Europe for the first time in summer 2006. The last clinical case of that first season of bluetongue was reported in mid-Jan 2007. After a break of several months the disease re-emerged, and the first BTV infection in the UK (with BTV type 8, the
same as in Belgium and surrounding countries) was confirmed by IAH on 22 September this year.

Taking into account air temperatures at the centre of the 2006 outbreak, and the growth of the virus at various temperatures, Wilson and colleagues have calculated that mid-April 2007 was the earliest time by when the virus would have grown to sufficient levels for the overwintering midges to be able to successfully infect animals when taking a blood meal. This agrees with the estimate made in Germany based on blood tests detecting antibody to the virus in the first cow observed to have developed disease.

The findings of Wilson and colleagues suggest that overwintering of the disease could simply be a combination of the long term survival of adult midges at low temperatures, retention of the virus in the midges, with short periods of virus growth during periods when the temperature
reached 15 degrees C. Once temperatures significantly exceeded 15 degrees C, which they
did in early to mid April, the virus more rapidly grew to the point at which the midges became fully infectious; the second season of bluetongue had begun.

It is quite possible that this phenomenon will be repeated in 2008, unless steps are taken to prevent it. Vaccination is considered to be the best defence against bluetongue. Vaccines against BTV-8 are expected to become available during early 2008. The progression of the disease on
the continent during 2007, combined with the analysis of Wilson and colleagues, suggests that for vaccination to be most successful it wouldneed to be undertaken by Spring 2008.

Dechra Veterinary Products has improved its 50 ml Somulose kit and released a new booklet “Guide to Equine Euthanasia using the Somulose 50 ml kit” to assist vets in administering the humane chemical euthanasia agent Somulose®

The changes have been made in response to information which indicated that some users have been experiencing difficulty administering Somulose® at the correct flow rate.

FMD
There is no change in the situation with FMD. Intensive surveillance is still ongoing in the PZ and SZ and plans are being formulated to allow lifting of the SZ once 21 days after primary C&D of the last premises has taken place.

BLUETONGUE
At 5pm on 8th October there was 30 cases of Bluetongue confirmed. Most of these are still in the Ipswich area with 2 in the Lowestoft area and 2 in Essex. The Essex cases although within the present BT 20km zone, may require a small change to the area.

Approximately 50% of these cases are detected on clinical signs. The remainder are being picked up on surveillance bleeding. About 50% of the herds tested are proving positive, but only up to 6% of animals within each herd are positive.

If you are interested in seeing photographs of the types of lesions being seen in the Ipswich are due to Bluetongue these are available at:

www.vla.gov.uk/science/science-viral-bluetongue.htm

Veterinary Laboratory Agency are now accepting live animals from outside the FMD PZ and SZ.

Horse owner Cate Ashton has launched a new website http://www.manage-my-horse.com/ for 'conscientious horse owners, yard managers and equestrian professionals'.

The impressive-looking (and free) site allows members to record almost every facet of their horse’s life in one place – breeding, training and exercise journals, accident and rehabilitation records, health, wellbeing, worming, vaccination and medical information, weight and condition scoring, competition records and all expenses and income.

In addition there is a diary to store appointments, an address book for personal and business contacts and a forum. The feed section allows for management of diet and nutritional needs and the reporting section gives printouts and reports instantly.

Worth recommending to your clients?

FMD
There have been no changes in the FMD situation. The latest epidemiology report on FMD is available at:

http://www.defra.gov.uk/animalh/diseases/fmd/pdf/epidreport300907.pdf

BT
There are now 26 premises with confirmed Bluetongue, 14 of these have been picked up on surveillance. Initial surveillance is by serology and this is followed up with PCR when positive results occur.

The problem of slaughter capacity for lambs within the BT zone is being addressed with the use of slaughter-houses on the edge of the area at Brighton and Lincoln. Licences for movement to these premises will be available shortly.

Over the last 24 hours there has been a number of changes to the majority of the licences in force at present. These include addition of multiple pick up and drop offs; new 20-day stand still requirements etc. on some licences. These licences will keep changing on a regular basis and we advise you to keep looking at the Defra website.

http://www.defra.gov.uk/animalh/diseases/fmd/movements/index.htm

CVS Group has been successfuly floated on the alternative investment market at a market value of £105.7 million.

CVS was established in August 1999 and with financial backing from funds managed by Sovereign Capital, it commenced the consolidation of the veterinary practice market. To date it has made 39 acquisitions and now comprises 45 practices nationwide together with three diagnostic laboratories.

Based in Diss, Norfolk, CVS operates as two divisions. The practice division is composed of 127 small animal veterinary surgeries, more than double the number of small animal veterinary surgeries operated by the nearest competitor, and one equine surgery; the three laboratories making up the diagnostic division provide services to CVS and to third parties. CVS currently employs over 1,200 staff, including over 270 vets.

Vetxx is on the hunt for case reports of acute moist dermatitis treated with Fuciderm® gel. Practitioners that send in more than six before the 30th November 2007 will receive a Fisher space pen, and be entered into a prize draw for an all expenses paid trip to the World Congress of Veterinary Dermatology 2008 in Hong Kong.

Case study reporting forms have been sent to all practices. If you haven't received yours and want to enter, call Vetxx on 01844 261030

Net-Tex Industries, the UK's leading producer of midge and other insect repellent sprays and creams for use on livestock, has produced a new midge repellent formulation which the company hopes will help combat bluetongue before a successful vaccine is developed.

Tony Meakin, Managing Director of Net-Tex, believes many of the lessons learned by UK and South African development trials could be applied to Bluetongue prevention in Britain. “Midges must be prevented from biting hosts to prevent infection. Reliance on insecticides (which aim to kill the midge) are less effective as the midge must bite the host to ingest the poison. The midge may die but only after it has infected the host with the virus!”

A repellent product must show longevity/residuality. It must last for at least 2 to 3 days, but must show controlled release throughout the 2 to 3 day residual period. “We use technology from the perfume industry to achieve these objectives with our specific midge repellent ingredients” Tony said.

Net-Tex says it will be working alongside DEFRA and government vets in their attempts to lessen the impact of this disease.