Re: Exotisch virus maakt koeien en schapen ziek
Schmallenbergvirus lijkt op het Cache Valley Virus in de VS
Het "Cache Valley Virus" is endemisch in de Verenigde Staten ( endemisch wil zeggen de ziekte blijft voorkomen in een bepaald gebied).
De ziekte veroorzaakt doodgeboren en misvormde lammeren. De beschreven symptomen in het onderstaande bericht van ProMED lijken erg op de syptomen die beschreven worden in Nederland.
Opvallend in beide onderstaand berichten: een mogelijk menselijke besmetting bij een hertenjager. Het zou een enkele uitzondering zijn op de regel: geen menselijke besmettingen door een Akabane-achtig virus. (Link naar artikel: Life-Threatening Cache Valley Virus Infection )
De jager werd niet via besmette schapen geïnfecteerd, maar via muggen veronderstelt men. Herten (reeën in Nederland?) zouden het reservoir van het virus kunnen zijn.
Ook geeft het bericht aan, dat nog veel onbekend is van het virus.
In de VS is volgens de berichten een vaccin beschikbaar.
Nog een bericht over Cache Valley Fever, met informatief commentaar:
Schmallenbergvirus lijkt op het Cache Valley Virus in de VS
Het "Cache Valley Virus" is endemisch in de Verenigde Staten ( endemisch wil zeggen de ziekte blijft voorkomen in een bepaald gebied).
De ziekte veroorzaakt doodgeboren en misvormde lammeren. De beschreven symptomen in het onderstaande bericht van ProMED lijken erg op de syptomen die beschreven worden in Nederland.
Opvallend in beide onderstaand berichten: een mogelijk menselijke besmetting bij een hertenjager. Het zou een enkele uitzondering zijn op de regel: geen menselijke besmettingen door een Akabane-achtig virus. (Link naar artikel: Life-Threatening Cache Valley Virus Infection )
De jager werd niet via besmette schapen geïnfecteerd, maar via muggen veronderstelt men. Herten (reeën in Nederland?) zouden het reservoir van het virus kunnen zijn.
Ook geeft het bericht aan, dat nog veel onbekend is van het virus.
In de VS is volgens de berichten een vaccin beschikbaar.
Cache Valley Virus
Cache valley virus is a bunyavirus that causes fetal death, still-birth and congenital malformations such as arthrogryposis and anencephaly in sheep. This is an arbovirus that is transmitted by mosquitoes.
Cache Valley virus as a human pathogen?
Cache Valley virus has been suggested to be a cause of neural tube defects in humans, although a study in 1997 could not serologically link infection with anencephaly and other defects.
Cache Valley virus was isolated from a deer hunter in North Carolina who suffered life-threatening, multi-organ failure, and recent serologic evidence suggests that deer may be a reservoir in nature.
However, the true zoonotic impact of Cache Valley virus remains to be determined, and people are most likely infected via mosquito bites rather than by direct contact with infected animals.
References:
Edwards, J.F. and K. Hendricks. 1997. Lack of serologic evidence for an association between Cache Valley virus infection and anencephaly and other neural tube defects in Texas. Emerg. Infect. Dis. 3:195-197.
McLean, R.G. et al. 1996. The role of deer as a possible reservoir host of potosi virus, a newly recognized arbovirus in the United States. J. Wildlife Dis. 32:444-452. (Also discusses CVV serology in deer)
Sexton, D.J. et al. 1997. Life-threatening Cache Valley virus infection. N. Eng. J. Med. 336:547-549.
VetMed
Cache valley virus is a bunyavirus that causes fetal death, still-birth and congenital malformations such as arthrogryposis and anencephaly in sheep. This is an arbovirus that is transmitted by mosquitoes.
Cache Valley virus as a human pathogen?
Cache Valley virus has been suggested to be a cause of neural tube defects in humans, although a study in 1997 could not serologically link infection with anencephaly and other defects.
Cache Valley virus was isolated from a deer hunter in North Carolina who suffered life-threatening, multi-organ failure, and recent serologic evidence suggests that deer may be a reservoir in nature.
However, the true zoonotic impact of Cache Valley virus remains to be determined, and people are most likely infected via mosquito bites rather than by direct contact with infected animals.
References:
Edwards, J.F. and K. Hendricks. 1997. Lack of serologic evidence for an association between Cache Valley virus infection and anencephaly and other neural tube defects in Texas. Emerg. Infect. Dis. 3:195-197.
McLean, R.G. et al. 1996. The role of deer as a possible reservoir host of potosi virus, a newly recognized arbovirus in the United States. J. Wildlife Dis. 32:444-452. (Also discusses CVV serology in deer)
Sexton, D.J. et al. 1997. Life-threatening Cache Valley virus infection. N. Eng. J. Med. 336:547-549.
VetMed
Nog een bericht over Cache Valley Fever, met informatief commentaar:
CACHE VALLEY VIRUS, OVINE - USA: (NORTH DAKOTA)
***********************************************
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 14 Jan 2011
Source: KFGO.com [edited]
The Cache Valley virus may have been responsible for recent abortions in sheep in central North Dakota.
"Preliminary laboratory investigation implicates the Cache Valley virus," says Neil Dyer, director of North Dakota State University's (NDSU) Veterinary Diagnostic Laboratory.
Determining whether Cache Valley was the cause of the abortions is difficult because the virus is not viable by the time its effects are noticed, he adds. Diagnosis often requires the demonstration of viral antibodies in serum or body fluids.
"It has the most detrimental effect on ewes during the 1st trimester of pregnancy," says Reid Redden, NDSU Extension Service sheep specialist. "Wet and warm conditions during the late summer and fall of 2010 were just right to propagate this disease."
Embryonic loss and fetal reabsorption occur in ewes that were infected with the virus within 30 days after breeding. Ewes infected with the Cache Valley virus from 30 to 45 days after breeding often will develop various congenital abnormalities affecting the nervous system, resulting in abortions, dystocia, weak lambs, stillbirths and lambs with severe structural deformities.
Lambs born alive are often too weak to survive and die within minutes of birth. Lambs born to ewes that were infected with the virus after 45 days of pregnancy may have no adverse effects.
"There is no effective treatment for lambs or ewes after the viral outbreak has occurred, nor is there a readily available vaccine," Redden says. "However, ewes that have been exposed to the virus appear to have lifetime immunity."
The most effective method of protecting ewes from the Cache Valley virus is to minimize their exposure to mosquito-infested areas during and shortly after the breeding season.
Numerous other infectious diseases also could result in abortions, as well as stillbirths and weak lambs, so producers who suspect the Cache Valley virus is in their flock should consult with their local veterinarian and/or the NDSU Veterinary Diagnostic Laboratory to confirm the diagnosis, Redden says.
-- communicated by: ProMED-mail promed@promedmail.org
[Cache Valley virus (CVV) is similar to Akabane virus. CVV is a mosquitoborne member of the Bunyviradae family. The disease is currently considered endemic in the United States.
Clinical signs in sheep include aborted fetuses, arthrogryposis (limb malformation), brachygnathia (lower jaw malformation), hydrocephaly (water on the brain), microcephaly (small brain), and spinal cord hypoplasia (under development) if the lamb is born alive. Those born alive usually do not survive long. The virus appears to have a predilection for the neurological tissue. The earlier in gestation the virus was acquire, the more severe the predilection. Infections between days 28-32 of gestation usually result in mummification and embryonic loss.
Congenital malformation and detection of the antibodies in the fetal fluids greatly aid diagnosis. While an absence of antibodies in the dam is significant, absence of antibody detection in the lamb does not preclude diagnosis of the disease.
In some areas vaccine is available and it should be used 30-60 days prior to breeding in an effort to prevent the disease. However, reducing the insect population, use of insect repellants and moving the flock away from low lying, water prone areas are also very helpful in preventing the disease. And some of these measures may be difficult to implement.
Cache Valley virus (CVV), a mosquitoborne member of the Bunyamwera serogroup, family Bunyaviridae, genus Orthobunyavirus, is geographically widespread in North America, where it circulates between mosquitoes and mammals (1). It has previously been associated with only a single case of human disease, a fatal case of acute encephalitis in the southeastern United States (2).
1. Calisher CH, Francy DB, Smith GC, Muth DJ, Lazuick JS, Karabatsos N, et al. Distribution of Bunyamwera serogroup viruses in North America, 1956*1984. Am J Trop Med Hyg. 1986;35:429-43.
2. Sexton DJ, Rollin PE, Breitschwerdt EB, Corey GR, Myers SA, Dumais MR, et al. Life-threatening Cache Valley virus infection. N Engl J Med. 1997;336:547*9.
Portions of this comment were extracted from http://www.cdc.gov/ncidod/eid/vol12no05/05-1625.htm - Mod.TG
ProMedmail
***********************************************
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: 14 Jan 2011
Source: KFGO.com [edited]
The Cache Valley virus may have been responsible for recent abortions in sheep in central North Dakota.
"Preliminary laboratory investigation implicates the Cache Valley virus," says Neil Dyer, director of North Dakota State University's (NDSU) Veterinary Diagnostic Laboratory.
Determining whether Cache Valley was the cause of the abortions is difficult because the virus is not viable by the time its effects are noticed, he adds. Diagnosis often requires the demonstration of viral antibodies in serum or body fluids.
"It has the most detrimental effect on ewes during the 1st trimester of pregnancy," says Reid Redden, NDSU Extension Service sheep specialist. "Wet and warm conditions during the late summer and fall of 2010 were just right to propagate this disease."
Embryonic loss and fetal reabsorption occur in ewes that were infected with the virus within 30 days after breeding. Ewes infected with the Cache Valley virus from 30 to 45 days after breeding often will develop various congenital abnormalities affecting the nervous system, resulting in abortions, dystocia, weak lambs, stillbirths and lambs with severe structural deformities.
Lambs born alive are often too weak to survive and die within minutes of birth. Lambs born to ewes that were infected with the virus after 45 days of pregnancy may have no adverse effects.
"There is no effective treatment for lambs or ewes after the viral outbreak has occurred, nor is there a readily available vaccine," Redden says. "However, ewes that have been exposed to the virus appear to have lifetime immunity."
The most effective method of protecting ewes from the Cache Valley virus is to minimize their exposure to mosquito-infested areas during and shortly after the breeding season.
Numerous other infectious diseases also could result in abortions, as well as stillbirths and weak lambs, so producers who suspect the Cache Valley virus is in their flock should consult with their local veterinarian and/or the NDSU Veterinary Diagnostic Laboratory to confirm the diagnosis, Redden says.
-- communicated by: ProMED-mail promed@promedmail.org
[Cache Valley virus (CVV) is similar to Akabane virus. CVV is a mosquitoborne member of the Bunyviradae family. The disease is currently considered endemic in the United States.
Clinical signs in sheep include aborted fetuses, arthrogryposis (limb malformation), brachygnathia (lower jaw malformation), hydrocephaly (water on the brain), microcephaly (small brain), and spinal cord hypoplasia (under development) if the lamb is born alive. Those born alive usually do not survive long. The virus appears to have a predilection for the neurological tissue. The earlier in gestation the virus was acquire, the more severe the predilection. Infections between days 28-32 of gestation usually result in mummification and embryonic loss.
Congenital malformation and detection of the antibodies in the fetal fluids greatly aid diagnosis. While an absence of antibodies in the dam is significant, absence of antibody detection in the lamb does not preclude diagnosis of the disease.
In some areas vaccine is available and it should be used 30-60 days prior to breeding in an effort to prevent the disease. However, reducing the insect population, use of insect repellants and moving the flock away from low lying, water prone areas are also very helpful in preventing the disease. And some of these measures may be difficult to implement.
Cache Valley virus (CVV), a mosquitoborne member of the Bunyamwera serogroup, family Bunyaviridae, genus Orthobunyavirus, is geographically widespread in North America, where it circulates between mosquitoes and mammals (1). It has previously been associated with only a single case of human disease, a fatal case of acute encephalitis in the southeastern United States (2).
1. Calisher CH, Francy DB, Smith GC, Muth DJ, Lazuick JS, Karabatsos N, et al. Distribution of Bunyamwera serogroup viruses in North America, 1956*1984. Am J Trop Med Hyg. 1986;35:429-43.
2. Sexton DJ, Rollin PE, Breitschwerdt EB, Corey GR, Myers SA, Dumais MR, et al. Life-threatening Cache Valley virus infection. N Engl J Med. 1997;336:547*9.
Portions of this comment were extracted from http://www.cdc.gov/ncidod/eid/vol12no05/05-1625.htm - Mod.TG
ProMedmail
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