Posts Tagged ‘UK’

UK HIV cases higher than ever

Friday, November 27th, 2009

More people than ever before are living with HIV in the UK but more than a quarter do not know they have it, figures show. The number of estimated cases rose by 8% between 2007 and 2008, says the Health Protection Agency. But it is thought 22,000 of the 83,000 people with HIV do not know they are infected.

More people than ever before are living with HIV in the UK but more than a quarter do not know they have it, figures show. The number of estimated cases rose by 8% between 2007 and 2008, says the Health Protection Agency. But it is thought 22,000 of the 83,000 people with HIV do not know they are infected.

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Bluetongue virus

Friday, September 28th, 2007

Bluetongue virus Bluetongue is a highly infectious virus disease of ruminants. Cattle and goats are major hosts of the virus, but in these species infection is usually asymptomatic despite high virus levels, allowing the disease to circulate in the absence of any symptoms. Sheep and deer are usually the only species to exhibit symptoms of infection. Bluetongue infections are marked by a high fever, excessive salivation, swelling of the face and tongue and cyanosis of the lips and tongue (turning blue). Infected animals become lame and listless. Ulcers appear around the mouth, nose and eyes. Then the neck may start to swell, followed by the head. The animal becomes lame, starts bleeding internally and breathing becomes difficult. The incubation period for bluetongue is 5-20 days. The mortality rate is normally low, but infected animals lose condition and there is a high mortality rate of 70% or more in susceptible breeds of sheep (due to secondary bacterial infections). While infected animals can recover, productivity is reduced with milk yields in dairy herds dropping by about 40%.

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Bluetongue virus (BTV) is a Reovirus of the genus Orbivirus. The virus is transmitted by midges, in particular Culicoides imicola and a few other species. Of more than 1,400 species of midges known world-wide, only around 20 culicoid species are known to be involved in transmission of bluetongue virus. Bluetongue can also be transmitted directly from one animal to another through semen and transplacentally. Bluetongue occurs in Australia, the USA, Africa, the Middle East, Asia and Europe, generally between latitudes 35°S and 50°N. It occurs around the Mediterranean in summer, subsiding when temperatures drop in winter. In Europe the disease has been spreading north since October 1998, possibly as a result of climate change. In August 2006 bluetongue spread to the Netherlands, then Belgium, Germany, Holland, and Luxembourg. The first ever case of bluetongue in the UK was reported in Suffolk on 23rd September 2007. On 28th September 2007 Defra confirmed that bluetongue is now endemic in the UK.

Unlike foot and mouth disease, bluetongue cannot be controlled by culling of infected livestock alone. Since midges form a reservoir of infection in endemic areas, you would also need to kill all the midges to eradicate the disease. Another complication is there are at least 24 distinct serotypes of the virus (based on the lack of cross neutralisation). Vaccination against one serotype does not usually confer protection against any of the other serotypes. The antigenic diversity of Bluetongue virus is due to both antigenic drift (accumulation of point mutations) and antigenic shift (reassortment of individual gene segments). The virus which has affected northern Europe and the UK is known as BTV8.

Live attenuated BTV vaccines containing a weakened form of the live virus are cheap, easy to produce and can be administered in a single dose. They are effective in controlling clinical outbreaks of bluetongue. However, the disadvantages of attenuated BTV vaccines are:

  • Risk of reassortment with virulent wild viruses which potentially could give rise to new virulent strains.
  • Potential for reversion to virulence both in the vertebrate host and in vector insects.
  • Attenuated BTV can cross the placenta and pregnant ruminants vaccinated with attenuated vaccines may suffer foetal loss.
  • Existing vaccines are designed for sheep; there is little data on their safety and effectiveness in other species.

There have been attempts to develop inactivated (killed) whole virus vaccines for BTV for the past 25 years, but none have yet been produced commercially. Inactivated vaccines are they more expensive to produce than attenuated vaccines and also require at least two doses with an adjuvant to generate a protective immune response. Bluetongue virus is not usually contagious for humans, and meat and dairy products pose no hazard. However, there is some concern over the potential spread via blood from infected people.

Bluetongue: Latest News

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UK Foot and Mouth Disease Outbreak

Saturday, September 22nd, 2007

Dead cow

  • 23rd September: A suspected new case of foot-and-mouth is being investigated on the Hampshire-West Sussex border. Bluetongue is confirmed on a farm in Suffolk.
  • 14th September: Defra announces that a second farm in Surrey is affected, imposes new protection and surveillance zone and confirms that sequencing tests of the virus have shown it to be type 01 BFS67, the same strain of virus responsible for the August outbreak.
  • 8th September: The last restrictions imposed on livestock movement in the UK following the foot-and-mouth disease outbreak were lifted, but the earliest the UK can achieve international foot-and-mouth disease-free status is 7th November.

Defra: Interactive map

10 Facts About Foot and Mouth Disease:

  1. Foot-and-mouth disease (FMD) is a highly infectious disease of hoofed animals (ungulates) such as cattle, sheep, goats and pigs. It can also infect elephants, rats, and hedgehogs.
  2. The symptoms of FMD are fever followed by the development of vesicles (blisters) chiefly in the mouth and on the feet.
  3. Affected animals suffer weight loss from which they do not recover for several months, and in cows milk production can decline significantly. Although most animals eventually recover from FMD the disease can be fatal, especially in newborn animals.
  4. Foot and mouth disease is caused by a Picornavirus.
  5. FMD has an incubation period of 2-14 days before symptoms appear. The virus can survive in dry faecal material for 14 days in summer, in slurry for six months in winter, in urine for 39 days and on the soil for up to 28 days.
  6. Some infected animals remain asymptomatic carriers of FMD which can transmit the disease to other animals.
  7. The last major outbreak of foot and mouth disease in the UK in 2001 led to the slaughter of between 6.5 to 10 million animals and is estimated to have cost the country up to £8.5 billion.
  8. The United States, Canada, Australia, Japan, Indonesia and Korea are currently free of FMD, but the disease is present in Eastern Europe, Asia, Africa and South America.
  9. Vaccination against FMD is difficult because there are seven serotypes of the virus and a vaccine for one serotype does not protect against any others. Vaccination only provides temporary immunity. Defra Decision Tree for Disease Control Strategies against FMD
  10. Humans can be infected with foot-and-mouth disease through close contact with infected animals, but this is extremely rare and human infections are not fatal. Because the virus that causes FMD is sensitive to stomach acid, it cannot spread to humans via consumption of infected meat or milk.