ne of the responsibilities of a livestock association is to adequately inform its participants

of important developments within the industry including developments in the field of

health and disease. This article concerns recently confirmed cases of Bovine Viral

Diarrhea Virus (BVDV) infection in alpacas in North America. Although BVDV was initially

thought to pose very minimal risk to llamas and alpacas the confirmation of several cases of

persistently infected cria has led to a reevaluation of this thought. Although many questions still

exist about the prevalence of infection and the degree of susceptibility of our animals the

Association believes a cautionary approach to the disease at this stage is appropriate.

BVDV infection is not a new disease, approximately 50 – 90% of adult cattle in Canada carry

BVDV antibodies, indicating prior exposure to the virus. Similar exposure rates are found in

cattle worldwide.

Extrapolating information from the cattle industry the key to BVDV transmission is the pregnant

female and the now known fact that viral infection of a pregnant female camelid can result in:

- birth of a normal cria if the fetus was able to respond to the infection

- birth of a persistently infected (PI) cria

- congenital damage to the cria

- abortion of the cria

These scenarios, the latter three of course resulting in economic and emotional loss, are likely

dependant on the timing of infection as it relates to the period of gestation in a pregnant female

who has never previously been exposed to BVDV. Prior exposure to the virus, before pregnancy,

will likely result in the production of antibodies that may convey some immunity to the

developing fetus.

The principal cause of the spread of the disease lies with the persistently infected cria. The

immune system of a fetus infected with the BVDV virus at a certain stage of gestation (in cattle it

is believed to be the first and early to middle second trimester) will not recognise the virus as an

infectious agent. At birth the cria may appear to be normal, but will be persistently infected,

shedding vast quantities of BVDV for life, and infecting other animals. They may even become

dams themselves and give birth to additional PI cria resulting in further spread of the disease.

While some of the confirmed cases of PI cria in North America have been characterised by low

birth weight, poor doing cria it is important to realise that they may appear to be perfectly normal.

These PI cria are the main sources of infection spreading large amounts of BVDV in saliva, nasal

secretions, urine and faeces. The virus can spread horizontally from animal to animal or vertically

from female to cria or fetus. Equipment such as halters, gloves, boots etc can carry BVDV but all

major groups of disinfectants will kill it. Since spread of a virus by direct contact is a relatively

slow process, farm outbreaks in cattle herds can last from several weeks to a few months.

As stressed, the prevalence of the disease in Canada and its implication to llamas and alpacas is

not at the moment clearly understood. However, as the transporting of females often with cria to

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different farms for outside breeding is a part of our industry, more so than in other livestock

industries, it would be prudent for us to take some precautions. Co-operation from breeders is an

important part of this process. We applaud the efforts of some breeders in this regard who have

taken the effort to inform others of the existence of PI cria in their farms. It must also be

remembered that since BVDV has what is believed to be a short lived existence in the

environment, removal of the source of infection, which unfortunately means euthanasia of the PI

cria, effectively and fairly rapidly removes the possibility of re-infection on individual farms.

If a PI cria is confirmed on an individual farm there is a need to disclose to other breeders that

may have had a pregnant female on the farm at the same time. This enables those breeders to take

appropriate precautions to prevent the possible spread of the disease to their own and other herds.

Those precautions should be testing the suspected female for the presence of BVDV antibodies

and if a positive result is recorded, isolating that female immediately prior to the birth of the cria.

The cria should then be tested for the presence of the live virus. The cria should not be permitted

to have nose to nose contact with pregnant females and strict hygiene methods should be adopted

when administering to the cria until the results of the tests are known. All confirmed PI cria

should be immediately euthanised and reported. We are also recommending that all aborted cria

be specifically tested for BVDV and all poor doing or unhealthy cria be isolated from all pregnant

females and not transported to other farms until tested for the presence of the virus.

Dr Dale Godson, a Diagnostic Immunologist/Virologist with Prairie Diagnostic Services located

at the Western College of Veterinary Medicine in the Department of Veterinary Microbiology at

the University of Saskatchewan, has extensive experience with BVD, and has generously agreed

to make himself available for consultation with your vet and to accumulate data concerning the

disease in llamas and alpacas.

The virus is present world-wide, cattle breeders have dealt with it for many years, cases of

persistently infected cria in alpacas have been confirmed both in North America and the U.K. by

virology laboratories. It is only by reporting cases of confirmed PI cria and abortions resulting

from exposure to the BVDV virus that will be able to get an indication of the prevalence of this

disease in our herds. It is only then that we can hope to obtain the knowledge that will ultimately

lead to professional advice on what, if any, additional control methods, such as vaccination may

be necessary in the future.

We have written a letter of support for a study being proposed by Raul C. Mainar-Jaime DVM

Phd, Associate Professor with the Department of Veterinary Microbiology at the Western College

of Veterinary Medicine. If accepted, the proposed project will begin by investigating the extent of

BVDV infection in a representative population of alpaca herds and Dr. Mainar-Jaime will be

looking for breeders to participate in the study. We encourage your co-operation.

CLAA Board of Directors