Reasonable Rascal
04-18-02, 16:39
Date: Wed 17 Apr 2002
From: ProMED-mail <promedmail.org>
Source: BBC News Online, Wed 17 Apr 2002 [edited]
<http://news.bbc.co.uk/hi/english/health/newsid_1934000/1934692.stm>
Camelpox virus: Close Relationship to Variola (Smallpox) Virus
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Scientists have discovered that a poxvirus isolated from camels is a much closer relative to the virus causing smallpox in humans than had been thought. The results suggest that camelpox virus could evolve to cause disease in humans. It also raises fears that it could be used as a biological weapon.
New Scientist magazine reports that Dr Geoffrey Smith, of Imperial College in London, has closely studied a strain of camelpox virus isolated from camels in Iran in 1970. Dr Smith told New Scientist magazine that: "It was surprising how close these 2 viruses were. It could be that only a small set of changes would be necessary for camelpox virus to infect people."
The viruses that cause smallpox and camelpox are orthopoxviruses [i.e., members of the genus _Orthopoxvirus_ of the Sub-family _Chordopoxvirinae_ of the Family _Poxviridae_. The genus _Orthopoxvirus_ includes (besides Camelpox virus): Cowpox virus, Ectromelia virus (Mousepox virus), Monkeypox virus, Raccoonpox virus, Taterapox virus, Vaccinia virus, Variola virus (Smallpox virus), and Volepox virus. - Mod.CP].
Dr. Smith's research has shown that the genetic make-up of camelpox virus and smallpox virus is remarkably similar -- even in the outer regions which usually vary between virus species.
Dr Lev Sandakhchiev, Head of Vector, the Russian laboratory that holds one of the 2 remaining official stocks of smallpox virus, said it was inevitable that another virus would evolve to fill the gap left by the
deadly smallpox virus. However, Dr. D.A. Henderson, who led the global campaign to eradicate smallpox, is skeptical that camelpox will one day pose a risk to humans. The virus has so far shown little interest in humans, and camel handlers appear unharmed despite prolonged exposure.
Camelpox is endemic among the world's 20 million camels and there is no vaccine. But it is possible that camel handlers show no symptoms of infection only because they are immunised by exposure at an early age. Adults who are new to camels, and lack immunity to any orthopoxvirus now that smallpox vaccination has stopped, might provide the virus with novel opportunities. Dr David Brown, of the Public Health Laboratory Service, told BBC News Online: "It is a theoretical possibility, however it has been 20 years since smallpox was eradicated and vaccination stopped and there is no evidence that camelpox virus has filled the niche during this time."
In 1995, the Iraqi government admitted to UN weapons inspectors that its weapons scientists were working with camelpox virus. They claimed they wanted to use it as a weapon to which Iraqis, who are used to
camels, would be immune, whereas foreign troops would not be immune.
---------------------------------------------
Reprinted under fair use for education.
From: ProMED-mail <promedmail.org>
Source: BBC News Online, Wed 17 Apr 2002 [edited]
<http://news.bbc.co.uk/hi/english/health/newsid_1934000/1934692.stm>
Camelpox virus: Close Relationship to Variola (Smallpox) Virus
-------------------------------------------
Scientists have discovered that a poxvirus isolated from camels is a much closer relative to the virus causing smallpox in humans than had been thought. The results suggest that camelpox virus could evolve to cause disease in humans. It also raises fears that it could be used as a biological weapon.
New Scientist magazine reports that Dr Geoffrey Smith, of Imperial College in London, has closely studied a strain of camelpox virus isolated from camels in Iran in 1970. Dr Smith told New Scientist magazine that: "It was surprising how close these 2 viruses were. It could be that only a small set of changes would be necessary for camelpox virus to infect people."
The viruses that cause smallpox and camelpox are orthopoxviruses [i.e., members of the genus _Orthopoxvirus_ of the Sub-family _Chordopoxvirinae_ of the Family _Poxviridae_. The genus _Orthopoxvirus_ includes (besides Camelpox virus): Cowpox virus, Ectromelia virus (Mousepox virus), Monkeypox virus, Raccoonpox virus, Taterapox virus, Vaccinia virus, Variola virus (Smallpox virus), and Volepox virus. - Mod.CP].
Dr. Smith's research has shown that the genetic make-up of camelpox virus and smallpox virus is remarkably similar -- even in the outer regions which usually vary between virus species.
Dr Lev Sandakhchiev, Head of Vector, the Russian laboratory that holds one of the 2 remaining official stocks of smallpox virus, said it was inevitable that another virus would evolve to fill the gap left by the
deadly smallpox virus. However, Dr. D.A. Henderson, who led the global campaign to eradicate smallpox, is skeptical that camelpox will one day pose a risk to humans. The virus has so far shown little interest in humans, and camel handlers appear unharmed despite prolonged exposure.
Camelpox is endemic among the world's 20 million camels and there is no vaccine. But it is possible that camel handlers show no symptoms of infection only because they are immunised by exposure at an early age. Adults who are new to camels, and lack immunity to any orthopoxvirus now that smallpox vaccination has stopped, might provide the virus with novel opportunities. Dr David Brown, of the Public Health Laboratory Service, told BBC News Online: "It is a theoretical possibility, however it has been 20 years since smallpox was eradicated and vaccination stopped and there is no evidence that camelpox virus has filled the niche during this time."
In 1995, the Iraqi government admitted to UN weapons inspectors that its weapons scientists were working with camelpox virus. They claimed they wanted to use it as a weapon to which Iraqis, who are used to
camels, would be immune, whereas foreign troops would not be immune.
---------------------------------------------
Reprinted under fair use for education.