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An overview of bovine herpesvirus 1 by Lyndsay Lawrence, Technical Manager, AgriHealth NZ Bovine herpesvirus 1 (BoHV-1) was demonstrated to cause disease in cattle as early as the
1920s . However, there is speculation that it was associated with disease before this . The virus
is found throughout the world and is prevalent in the New Zealand cattle herd .
BoHV-1 is a DNA virus, genus infections are unidentifiable clinically but Virus subtypes
Varicellavirus, in the family Herpeto- can be reactivated by stress or corticosteroid All viral isolates of BoHV-1 to date belong viridae. Although it is widely therapy. Re-excretion of the virus is usually to a single viral species with three subtypes: distributed among cattle, its host range is clinically silent but the amount of re-excreted BoHV-1.1, BoHV-1.2a and BoHV-1.2b. limited. Large amounts of virus are shed in virus can be high and last for several days. Most BoHV-1.1 strains have been isolated respiratory, ocular and reproductive secretions Thus, transmission of BoHV-1 is perpetuated from respiratory tract disease (or abortion of infected cattle, and BoHV-1 is readily by direct contact between infected cattle as cases) and BoHV-1.2 strains from genital transmitted. The incubation period for BoHV- well as by virus shedding due to reactivation organ lesions. However, this distinction 1 in naïve animals is two-to-six days. Cattle of latent infection. is not exclusive, and nasal infection with are the principal reservoir and usual source BoHV-1 eradication campaigns have been BoHV-1.2 can cause respiratory disease and implemented in several European Union intrauterine inoculation with BoHV-1.1 can In common with other herpesviruses, countries. These tend to employ vaccination cause genital lesions. In practice, it is difficult infection with BoHV-1 results in life-long, (using marker vaccines), serological testing to distinguish between the isolates obtained latent infections in the nervous tissue. Latent and movement control.
from reproductive and respiratory mucosae Computerised Animal Health Planning: from page 10 At the same time, the farmer would benefit from having a structured system put in place that ensured critical seasonal herd and flock health management tasks were implemented when they were supposed to be, “Farming is all about timing. If you do it on time you get the maximum rewards for your investment; if you don’t, you miss out,” To make such a programme work for both the vet and the farmer, however, one thing was mandatory – a simple, robust reminder system. Farmers needed to be reminded of what was coming up and clinics needed to know what products were going to be required in stock to Early versions of the AHP lacked this fundamental feature, Atkinson says, meaning they ended up sitting in the drawer and weren’t Emma Cuttance has implemented the system for VetEnt clients, implemented. What was needed was dedicated software that would allow for a dynamic, interactive plan tailored to each farm’s needs, with ongoing contact between the vet and the farmer as well as for product the all-important reminder function built in. sales. Reminders are sent seven days before the scheduled event and And, with funding from Atkinson and Merial Ancare, that is what again on the day. Computer Fanatics in Auckland has created. Using a range of pre-loaded Piopio vet Anna Martyn works closely with Richard Atkinson to templates, vets and their clients can now build short- and long-term implement the system for the practice’s clients and is enthusiastic tailored plans that cover all animal health priorities and objectives about its potential impact on the health and subsequent profitability of Typically, for Atkinson and Associates, the process begins in May “The ability of the AHP to quickly print a year calendar of tasks or June, with a farmer consultation at the clinic to scope out the plan and to capture product details including withholding periods, active and identify any issues or developments that need to be incorporated ingredients and dose rates, has proved very useful in meat quality to achieve the desired outcomes. After this, the detailed plan is drawn assurance programmes as wel .
up, reviewed with the client and finalised. “By utilising technology, the plan comes out of the drawer and From that point onwards, the reminder function, which can be into the forefront of the animal health and business decision-making fully automated with texts or emails or both, becomes the prompt for process,” she says. 12 VetScript | June 2012
Bovine herpesvirus 1: from page 12due to their close immunological and genetic general, IPV is not observed in respiratory to produce large areas over which the penile Conditions associated with
but can have marked effects upon the fertility infection with BoHV-1. Any temperature BoHV-1
spike in bulls has the risk of a negative effect on There are many clinical manifestations of The presenting lesions of IPV occur one-to- semen quality “down-stream” for up to eight infections with BoHV-1. Severity ranges from three days after mating with an infected bull. weeks. Cows served by bulls with mild or early overt clinical signs to clinically inapparent Infection of the vaginal and vulval mucosa infection may develop signs of IPV.
with BoHV-1 results in vesicles, pustules and BoHV-1 has also been associated with erosions or ulcers in the mucosal surface. An complication over one-to-two weeks. There is abortion, although this association has not associated mucopurulent vaginal discharge, a risk of penile or preputial scarring secondary been detected in New Zealand to date. In accompanied by dysuria may be present. to severe balanoposthitis, which can result in addition, BoHV-1 is associated with a fatal Affected cows may appear uncomfortable, adhesions between the penis and prepuce.
systemic condition in newborn calves. This inappetent and exhibit obvious pain during presentation is suspected to occur but has not their frequent attempts to urinate. equipment can constitute a hazard. The virus Fertility during this time can be reduced can survive in frozen semen. Insemination Under New Zealand conditions, BoHV-1 due to an unwil ingness to allow mating. Acute of susceptible cattle with semen containing infection often results in subclinical disease infection is a primary cause of early embryonic BoHV-1 can cause endometritis, shortened or presents with mild clinical signs. This mild mortality. IPV has been implicated in long, oestrus periods and reduction in conception disease tends to affect a large number of animals irregular returns to oestrus (“phantom” cows). rates in the recipient cow or heifer.
within a short time. Clinical signs include Healing of the ulcers takes place over two- milk drop, depression, inappetence, rise in to-three weeks and fertility returns to normal infection can develop a similar latency as cattle temperature, fever, coughing and profuse nasal as they heal. discharge. In addition, conjunctivitis with profuse ocular discharge may sometimes be Infectious pustular balanoposthitis
Other associated conditions
seen. The clinical course in affected animals (IPB)
is usually completed within seven to 14 days. Genital infection with BoHV-1 can lead to IPB conjunctivitis with ocular discharge. This is More severe disease does occur, with many in males. As with IPV, infection is spread via often seen in association with IBR symptoms.
animals in an affected herd showing signs of an venereal transmission. An important aspect of infections of all upper respiratory tract infection accompanied Balanoposthitis is infection of the penis types of BoHV-1 (in common with other by a significant drop in milk production. In and prepuce. It is relatively common in the members of the herpesvirus family) is that this presentation, mainly two-year-old dairy bull. Low-grade infection of the preputial the infected animal becomes a latent carrier. heifers are affected because they are exposed to cavity rarely causes clinical disease, but severe Reactivation of this latency can explain why the virus when entering the dairy herd. Older balanoposthitis can cause pain, unwil ingness viral infection and transmission is most often to serve, preputial stenosis and adhesions seen during periods of stress.
Infections with BoHV-1 are rarely fatal between the penis and prepuce. BoHV-1 is the unless complicated by secondary bacterial cause of severe, ulcerative infection localised in Prevention and control
infection. Latent infections or reactivation of the genital tract (IPB). Small raised nodules, Prevention via vaccination before “risk” latency are always features of infection with vesicles and necrotic foci are initially seen, periods is the recommended course of action. which develop into deep ulcers or coalesce against the effect of transient infection (and Infectious bovine rhinotracheitis (IBR) Figure 1: Acute balanoposthitis due to BoHV-1
therefore prevent symptoms that occur in even IBR is a highly infectious and contagious infection mild infections such as fever, inappetence, upper respiratory tract disease caused by BoHV-1. Clinically, it is characterised by In addition, the primary immune response exposure or a vaccination programme is able cattle are crowded together, for example, to successfully control the re-excretion of a during transport or in feedlots. IBR is spread by clinically affected cattle, or subclinical shedders, via coughing of virus-laden nasal combination with BVD vaccination) before sections or via nasal, ocular and oral discharges containing the virus being dropped into feed • if the bull was naïve (and mixed with an infected or latently infected animal(s)) Infectious pustular vulvovaginitis
(IPV)
Genital infection with BoHV-1 can lead to • if the bull is latently infected he will not IPV in females. The main source of genital Source: Reproduced with permission from infect the herd or naïve members of the Diseases of Cattle in Australasia; New Zealand infection is venereal transmission during Veterinary Association Foundation for herd (as reactivation of latency will be mating. Infection can be subclinical. In Continuing Education (2010).
VetScript | June 2012 13
Bovine Herpesvirus 1: from page 13
The recommendation to vaccinate calves Acknowledgement
Muylkens, B, J Thiry, P Kirten, F Schynts and E against BoHV-1 can also be justified. This is Thanks to authors TJ Parkinson, JJ Vermunt Thiry (2007) Bovine herpesvirus 1 infection and especially the case if they are to be transported infectious bovine rhinotracheitis – A review. Vet and J Malmo, and publishers, New Zealand Res 38(2): 181–209. long distances or co-mingled with animals Veterinary Association, for allowing use of from other farms. Again, this minimises any Figure 11.7.18 from the textbook Diseases of Parkinson, TJ, JJ Vermunt and J Malmo impact of transient infection. It also controls (2010) Diseases of Cattle in Australasia: A Comprehensive Textbook. Wel ington: New latency reactivating (if the calf is already a Zealand Veterinary Association Foundation for carrier) and, therefore, spreading virus to Bibliography
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Summary
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acute and latent infections of calves with bovine herpesvirus types 1 and 5. Arch Virol 146(4): To report suspected exotic land,
• Vaccination can be used to limit spread freshwater and marine pests, or exotic
diseases in plants or animals, call:
virus. Am J Vet Res 45(4): 790–794.
0800 80 99 66
and conceptus. Am J Vet Res 47(2): 14 VetScript | June 2012

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