Bovine Viral Diarrhea (BVD) - also know as Bovine Viral Diarrhea Virus (BVDV)
(posted on the NJAC Website 12/20/05)
Previously BVD was not considered a problem in alpacas. It came to my attention however when "Miss P", a cria which we purchased at a spring auction with her mom, was diagnosed as a PI cria. What is BVD? What is a Persistently Infected cria (PI)? Why should you be concerned about BVD?
BVD is a virus that is passed to alpacas through bodily fluids of an infected animal. Most times it is not a problem - alpacas become infected, mount a response with antibodies and clear the virus. Females who are exposed to the virus for the first time during pregnancy are a different story. Several problems can become an issue. For instance when a female is exposed to the virus for the first time in the early part of gestation, the fetus that she is carrying will never be able to mount antibodies to the virus and will always have the virus. After it is born it will continually shed the virus and spread it to other animals throughout its life. This cria is a Persistently Infected (PI) cria and must be culled to stop the spread of the virus.
"Miss P" was possibly the first PI cria Cornell University diagnosed. Fortunately we had quarantined our new purchase from the auction and when we tested our herd we never had a positive result for the active virus on our property. However, there were 4 females and one young male who tested positive for antibodies to BVD - which means they were probably exposed to the virus before they came to our farm. To prevent the spread of BVD precautions will be taken with the pregnant females who tested positive for BVD antibodies. They will be quarantined for birthing and kept quarantined until the cria is tested for BVD.
We were very fortunate that the virus did not spread. There are others in New Jersey and the Northeast who have not been as fortunate. To those that say NJ is just a 'hot spot' for BVD, I beg to differ. How many farms in other states have done testing? If so, have the farms been willing to share the info with other farms? The cria we purchased was from the west coast. Other animals we own who tested positive for antibodies came from New England and New Jersey.
One of the biggest problems I see with BVD is the breeder who ignores it or simply doesn't admit there is a problem. Once you know the status of your herd, it is a matter of herd management to eliminate BVD. The breeder who sold us "Miss P" continues to state that they have no problem and that "Miss P" obviously contracted BVD when she came to NJ. Remember, we purchased her as a cria at side and Dr. Dubovi classified her as a PI cria, which means her mother was exposed to the virus while "Miss P" was in utero. (i.e. while the dam was still on the west coast)
I do not expect that every farm who tests will show signs of BVD exposure. To the contrary, it probably is a small percentage. But unless you have a closed herd, never go to shows, never purchase new animals and never do outside breedings, exposure to the BVD infection can become an issue on your farm.
When NJAC members had a discussion on BVD last fall, it was a unanimous decision to help educate our members, other breeders and vets about BVD by sponsoring a seminar. On February 19, 2006 Dr. Ed Dubovi, one of the top veterinary virologists in the country, will discuss Bovine Viral Diarrhea in alpacas. Dr. Katrina Alger will talk about Quarantine Issues and Current Immunization Protocols. Even if you are planning to attend this seminar, we suggest that you familiarize yourself with BVD beforehand. The various links and reference articles listed below will help you to understand the basics of BVD.
Please pass this information on to fellow breeders and your vet. BVD is too important an issue to disregard. Ignoring it will not make it go away.
References About Bovine Viral Diarrhea (BVD) (posted on the NJAC Website 1/4/06)
2. Articles in both the December 05 MaPaca Newsletter (posted on the web www.mapaca.org)
Reference articles in
1. Camelid Quarterly:
a. June 2005: "BVD Virus" pg. 93
b. September 2005: "BVD in Camelids - A Practical Approach"
2. Alpacas Magazine:
a. Summer 2005 "Bovine Viral Diarrhea Virus" pg 144 and 146
b. Winter 2006 "ARF Update on BVD" pg 42
MORE ARTICLES & INFORMATION
List of Articles from the CLAA:
Viral Diarrhea - BVD - A newly
recognized serious health problem for alpacas
Nancy Carr MD and Susy Carman DVM PhD
Welcome to the Alpaca Research Foundation
The Alpaca Research Trust was established by the ARI Board of Directors in December, 1997 as a Colorado, non-profit corporation for charitable, educational and scientific purposes. The Board of Directors, of what is now known as the Alpaca Research Foundation, is composed of a select group of camelid veterinarians, research scientists and medical professionals. Their job is to establish research goals and critically evaluate research proposals from qualified research scientists.
The Mission of the Alpaca Research Foundation is to encourage and support scientific research which benefits the North American alpaca industry, primarily in the areas of alpaca health and husbandry, genetics and fiber.
Census: Confirmed BVDV Cases in Alpacas - Click Here.
Mid-Atlantic Alpaca Association (MaPaca) Teams up with the Alpaca Research Foundation (ARF) to Support Bovine Viral Diarrhea (BVDV) Research
Recent concerns about cases of BVDV in alpacas have been fueled by reports of several confirmed cases of persistently infected (PI) alpacas all across the United States and in Canada. (See the BVDV census on the ARF website). ARF has worked quickly to solicit research proposals designed to determine the prevalence of this virus in North American alpaca herds. The following two complementary proposals have now been approved for funding with a November 1, 2005 start date. We are very happy to report that the Board of Directors of MaPaca has agreed to fully fund the second of the two studies. ARF will fund the first.
1. An Epidemiologic Assessment of Bovine Viral Diarrhea Virus Infection in US Alpacas, to be conducted by En-Min (Eric) Zhou, MD, PhD and Julie Ann Jarvinen, PhD, DVM at Iowa State University, Ames, Iowa. 11/1/05-6/30/07,$17,600. The major goal of this study is to test the blood from 200 randomly selected alpaca herds across the US for virus neutralizing antibodies against two types of BVDV to determine how commonly and frequently alpacas are infected with BVDV. In this study, only alpacas older than 6 months will be tested. The investigators will also look for a relationship between potential risk factors such as exposure to cattle or participation in shows and the presence of antibody.
2. Bovine Viral Diarrhea Virus in North American Alpaca Herds: Determination of and Implementation of Control Strategies, to be conducted by Clayton L. Kelling, DVM, PhD, David R. Smith, DVM, PhD, David J. Steffe, DVM, PhD and Bruce W. Brodersen, DVM, PhD of the University of Nebraska, Lincoln, Nebraska, 11/1/05-10/31/06, $20,500.The major goal of this study is to determine the proportion of North American alpaca herds that are infected with BVDV by testing for the live virus as well as antibodies to the virus in crias under the age of 6 months. Participation of 200 herds will be needed to complete the study. If the virus is found to be active in a herd, further testing will be conducted to determine whether persistently infected carriers of the virus are present in the herd. In addition, the investigators will develop and help implement a plan for eliminating carrier animals and establishing BVDV-free herd status. Cost effective monitoring strategies will be developed whereby owners can certify their herds as BVDV-free.
Clayton Kelling and his research team at Nebraska have been at the forefront of developing testing and monitoring procedures for the control of BVDV in cattle and dairy herds. We are fortunate that they are willing to apply their expertise to this important problem in alpacas.
Completion of these studies will require cooperation from hundreds of alpaca owners across North America. All testing will be confidential. Only the herd owner will be notified of the results. If you are contacted and asked to supply blood samples from some of your alpacas, please plan to participate. By joining a study you will receive valuable, free information about the BVDV status of your herd and advice on how to achieve and maintain your herd's BVDV-free status. So take the first step. Join a study and get tested now! You will be helping all alpaca owners, including yourself, by agreeing to participate. To find out more about BVDV go to the ARF website at www.alpacaresearchfoundation.org .
BVDV - CONTROL WEBSITE
WISCONSIN DAIRY PRODUCER WEBSITE:
Proven protection from BVDV
type 1 and type 2…
there can be only one leader.
Let's Talk BVDV
Q: We have many well managed cow/calf operations in our
practice and most now use a 5-way MLV for their cow and calf vaccination
programs. A couple years ago we experienced some BVDV “breaks” which
convinced us to use a product with a Type 2 BVDV, and we have had fewer
overall incidents of BVDV since that time. However, another herd which
changed to a 5-way MLV recently experienced BVDV problems among some of
the cows and calves. The problem is now under control, but in the
diagnostic work up we requested analysis by PCR to determine the BVDV
genotype and to our surprise found it to be a Type 2. What is the degree
and extent of protection afforded by popular, known effective vaccines
against the two genotypes, subgenotypes, and all the different strains
Q: Our vet clinic has recently received information on
recombination in BVDV vaccines. Should we be worried about recombination
when using a modified live vaccine that contains both type 1 and type 2
cytopathic BVDV antigens in it?
Q: There seems to be a lot of information out recently
regarding BVDV vaccine biotypes, ie. cytopathic and noncytopathic. Is
this difference important in the selection of a MLV vaccine?
Q: With a modified live vaccine that contains both a
cytopathic type 1 and cytopathic type 2 BVDV that has been clearly
demonstrated to be safe in healthy calves, is it possible for this
vaccine to cause problems due to recombination?
Q: Is it true that if a persistently infected calf is
administered a modified live virus BVDV vaccine that the calf will
develop a mucosal disease and die?
Q: Could you review the important points in determining which
cow herds should be considered for PI testing and which should not?
Q: Is it true that the BVD virus can behave differently when
it infects reproductive tissues?
Q: At times it seems that BVD can be difficult to recognize
and confirm in the field. What factors are involved and why does it seem
to take a long time for BVD titers to come up after a natural infection,
and even sometimes after vaccination?
Q: What is the difference between
cytopathic and noncytopathic biotypes of BVDV? And can they convert back
Q: Our practice has conducted PI testing on several herds this
spring using the IHC ear notch test. The results in most cases were
negative, but in a couple of herds (which had experienced repro
problems) we identified PI calves. Please discuss some of the follow up
steps for continued control and management measures.
Q: What tests are used for identification
of PI animals?
Q: I recently heard the term CI. What is it, and what problems
might it cause?
Q: Our practice recommends vaccination of
calves at turnout/ branding time (approx. 2-3 months of age) and again
at weaning. We have found this to be a very effective program. What are
your thoughts related to vaccine response and interference of passive
maternal immunity with this initial vaccination?
Q: Some MLV vaccines that contain only a
Type I BVDV, claim that the product will cross protect against disease
caused by Type II BVD. Isn't it true that this cross protection is
incomplete and variable against virulent field isolates of BVDV?
MSU EXTENSION WEBSITE:
Bovine Viral Diarrhea Virus
Bovine Viral Diarrhea Virus (BVDV) BVDV is a small RNA virus which is a member of the genus Pestivirus. It is closely related to hog cholera virus in pigs and border disease virus in sheep. BVDV can infect all ages of susceptible cattle including the unborn fetus.
The disease is spread primarily by cattle persistently infected with BVDV. Cattle become persistently infected with BVDV when exposed to the virus as a fetus by transplacental infection. Cattle acutely infected with BVDV can shed the virus for short periods of time primarily in respiratory tract and nasal secretions. Virus can also be transmitted through semen of both acutely and persistently infected bulls.
Two genotypes of BVDV exist: Type I and Type II. Type II BVDV has been associated with more severe clinical disease including a hemorrhagic syndrome.
Cattle producers loose millions of dollars annually due to illness, pregnancy wastage, death and reduced production caused by infection with BVDV.
Clinical Outcomes of Infection
The clinical outcome following infection with BVDV is dependent on the following factors:
Control & Prevention
The key to the control and prevention of BVDV infection is to detect and eliminate cattle persistently infected with the virus
Elimination of Carrier Animals
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