Most animals will recover in several days without treatment. General control and prevention are discussed under Enzootic Pneumonia of Calves and Shipping Fever Pneumonia Enzootic Pneumonia of Calves and Shipping Fever Pneumonia Enzootic pneumonia and shipping fever pneumonia share many similarities in their respective etiologies and pathogeneses and in general measures for control and prevention.
Enzootic pneumonia Inactivated and modified-live vaccines are available and may serve to reduce losses associated with BRSV; however, there is a paucity of field trials to evaluate the efficacy of these vaccines. Bovine herpesvirus 1 BHV-1 is associated with several diseases in cattle: infectious bovine rhinotracheitis IBR , infectious pustular vulvovaginitis IPV , balanoposthitis, conjunctivitis, abortion, encephalomyelitis, and mastitis.
BHV-1 infections are widespread in the cattle population. In feedlot cattle, the respiratory form is most common. The viral infection alone is not life-threatening but predisposes to secondary bacterial pneumonia, which may result in death. In breeding cattle, abortion or genital infections are more common. Genital infections can occur in bulls infectious pustular balanoposthitis and cows IPV within 1—3 days of mating or close contact with an infected animal.
Transmission can occur in the absence of visible lesions and through artificial insemination with semen from subclinically infected bulls. Cattle with latent BHV-1 infections generally show no clinical signs when the virus is reactivated, but they serve as a source of infection for other susceptible animals. The incubation period for the respiratory and genital forms is 2—6 days. In the respiratory form, clinical signs range from mild to severe, depending on the presence of secondary bacterial pneumonia.
Nasal lesions consist of numerous clusters of grayish necrotic foci on the mucous membrane of the septal mucosa, just visible inside the external nares. They may later be accompanied by pseudodiphtheritic yellowish plaques. Conjunctivitis with corneal opacity may occur as the only manifestation of BHV-1 infection. In the absence of bacterial pneumonia, recovery generally occurs 4—5 days after the onset of signs.
Abortions may occur concurrently with respiratory disease but may be seen up to days after infection. They can occur regardless of the severity of disease in the dam. Abortions generally occur during the second half of pregnancy, but early embryonic death is possible. In genital infections, the first signs are frequent urination, elevation of the tailhead, and a mild vaginal discharge. The vulva is swollen, and small papules, then erosions and ulcers, are present on the mucosal surface.
If secondary bacterial infections do not occur, animals recover in 10—14 days. With bacterial infection, there may be inflammation of the uterus and transient infertility, with purulent vaginal discharge for several weeks. In bulls, similar lesions occur on the penis and prepuce. BHV-1 infection can be severe in young calves and cause a generalized disease.
Pyrexia, ocular and nasal discharges, respiratory distress, diarrhea, incoordination, and eventually convulsions and death may occur in a short period after generalized viral infection. In uncomplicated IBR infections, most lesions are restricted to the upper respiratory tract and trachea. Petechial to ecchymotic hemorrhages may be found in the mucous membranes of the nasal cavity and the paranasal sinuses. Focal areas of necrosis develop in the nose, pharynx, larynx, and trachea.
The lesions may coalesce to form plaques. The sinuses are often filled with a serous or serofibrinous exudate. As the disease progresses, the pharynx becomes covered with a serofibrinous exudate, and blood-tinged fluid may be found in the trachea.
The pharyngeal and pulmonary lymph nodes may be acutely swollen and hemorrhagic. The infection was present in all state dairy farms. In , only 3. In , 2. Table 2. BoHV-1 seroprevalence in cattle herds with bull's mothers among three most prevalent breeds in Slovenia.
Since independence of Slovenia in , imported cattle had been quarantined and tested for BoHV-1 antibodies; results are shown in Table 3. In , a study of the prevalence of BoHV-1 in herds with bull mothers was done. Out of 8, cattle, seropositive cattle were found in 38 herds Table 3.
Of the herds tested for BoHV-1 infection, Only one BoHVpositive animal was found in 16 farms. The highest percentage of serologically positive animals in a herd was 57 out of 66 Table 3. Results of serological tests for BoHV-1 antibodies in imported cattle and bulls' mother herds in Slovenia in the period — In , 4, blood samples from herds with bull mothers were tested. BoHVpositive animals were confirmed in 11 herds, of which only one herd that was negative in was positive, and the other 10 BoHVpositive herds were tested for the first time.
From to , to herds with bull mothers and candidates for herds with bull mother were included in yearly serological surveillance Table 4. Table 4. Results of BoHV-1 serological surveillance in herds with bull's mothers in Slovenia from to In a serological study in commercial dairy farms on BTM samples in the year Table 5 , the highest percentage of positive herds was found in Gorenjska 6. BoHV-1 positive samples were recorded in herds, representing 3.
In the other farms, there were animals of different breeds, of which farms kept at least one Holstein Friesian cattle. Table 5. Results of the study on the presence of BoHV-1 antibodies in bulk milk samples BTM in dairy herds producing milk for public consumption in Slovenia in the year BoHVpositive cattle were detected in 1, 3.
The highest herd prevalence was recorded in the region Kranj 8. Herds who also had Holstein Friesian cattle were positive most frequently among all herds.
These herds were most often descendants of animals from previous state farms. Figure 1. Prevalence of BoHV-1 positive herds by administrative regions in Slovenia in From to , bulls from ICs and BCYBs were tested systematically and at the breeder's request also other animals show animals and individual animals purchased and sold. Percentages of positive samples were from 0.
Samples with positive results belonged to cattle intended for sale or exhibitions, etc. Table 6. No clinical signs of infection were observed. The source of virus introduction and infection was never determined. The first IC with breeding bulls in Slovenia was established at the end of the s, and the collection of bull semen and AI was introduced, primarily in response to sexually transmitted diseases. Through this, AI has become the breeding norm on the majority of dairy farms in Slovenia The best bulls are used to obtain semen for AI and kept in quarantine conditions.
Calves from herds with bull's mothers are selected by the Slovene cattle breeding selection service. The development of virological diagnostics in also enabled the routine diagnosis of BoHV-1 virus infections The knowledge that BoHV-1 is also very successfully transmitted by infected semen was first introduced to control the disease in bulls in IC in the s. Due to the increased milk needs in Yugoslavia in the s, the intention was to increase milk production by importing high-milk breeds such as Holstein Friesian cows; they were imported from various European countries and from Israel.
This breed was bred on state dairy farms, while traditional breeds such as Brown cattle and Simmental cattle were present in private farms. At that time, imported cattle were not tested for BoHV-1 infection, so virus could be introduced into the country with the import of BoHV-1 positive Holstein Friesian cattle.
Herds with Holstein Friesian cattle were later detected heavily infected with the BoHV-1 in comparison to the lower detected prevalence in the herds of the private sector. Between and , By , all tested state-owned herds, with from to 1, dairy cows had been infected the BoHV-1 positive.
The reason for this can be result of intensive traffic of breeding livestock between individual state farms without testing for BoHV-1 infection before movements. These results Table 1 show that the infestation of Holstein Friesian cattle in state herds was significantly higher than in private sector herds, predominantly with Brown and Simmental breeds. Serological monitoring of cattle confirmed that BoHV-1 infection was present in all state-owned dairy farms and uncontrolled purchases of cattle from these farms were the main cause of infection for private herds.
Epidemiological analyses performed between and confirmed that BoHV-1 was widespread among Holstein Friesian cattle and less so among Simmental and Brown Swiss. After separation from Yugoslavia and the introduction of the democratic political system in Slovenia in , most state farms with Holstein Friesian breed collapsed and were depopulated or privatised.
Many cattle were culling or sold to private herds, uncontrollably spreading BoHV-1 to these farms After the number of imported cattle increased sharply, especially fattening. In period from to , a total The percentage of detected BoHV-1 seropositive animals from these imported countries was decreasing Table 3.
This can be attributed to the fact that these countries have already started with implementation BoHV-1 eradication programs during this period, which was also reflected in exported calves intended for further fattening. Imported cattle for fattening was for slaughter, trading of these animals to other breeders was not officially allowed. From the results of serological tests in the bulls' mother herds in Table 3 , The percentage of positives animals was higher because herds of Holstein Friesian cattle, mostly purchased from former large BoHV-1 positive state-owned herds, were also included in the investigations.
Surveillance started in with annual serological control in herds of bull's mothers. A BoHV-1 negative herd status was granted, after serological examination of all breeding animals, confirmed all animals are negative to BoHV-1 antibodies. Annual laboratory control of herds with bull's mothers was carried out until During this period, Learn More.
Groups of five animals were then given either 2, 3, 4, or 5 doses of interleukin-2 IL-2 0. Animals that received no IL-2 exhibited specific immune responses that are typical for BHV-1 infection, i. Treatment of animals with five doses of IL-2 significantly augmented all of these responses except serum neutralization P less than 0. Furthermore, the dose of IL-2 that was selected did not induce any non-specific responses, i.
Nor were there any clinical changes associated with IL-2 therapy e. Animals that were treated with less than five doses of IL-2 also exhibited elevated immune responses, but they were not significantly different from untreated immunized controls. Interestingly, animals given five doses of IL-2 responded to minor contaminants present in the gIV preparation. This allows speculation that this dose regimen of IL-2 is not only a potent adjuvant for conventional vaccine immunizing doses, but will also allow the use of minute quantities of antigen for immunization.
Full text is available as a scanned copy of the original print version. Get a printable copy PDF file of the complete article 1. Links to PubMed are also available for Selected References. These references are in PubMed.
A vaccination is available for control and is widely used. Both inactivated and live attenuated vaccines are available. The vaccination schedule consists of two vaccinations at a 3-week interval for inactivated vaccines, starting from the age of months to avoid interference with colostral antibodies. Live attenuated vaccines are administered either once or twice depending on the type of vaccine. Duration of immunity usually lasts from six months to one year.
Vaccination is recommended for young calves to prevent clinical signs. Vaccination of calves less than 3 months of age can be achieved by intranasal administration of attenuated vaccine.
This route is better for overcoming interference due to maternal immunity. Vaccinations should protect cattle clinically in case of infection and significantly reduce the shedding of field virus. Vaccinating latently infected animals may reduce the level of shedding from this group. Marker vaccines are also available and recommended. These are based on glycoprotein E gE deleted mutants, with detectable antibodies present to the gE antigen in marker vaccinated individuals indicating wild-type viral infection.
Kaashoek, M. Tvan A conventionally attenuated glycoprotein E-negative strain of bovine herpesvirus type 1 is an efficacious and safe vaccine. Vaccine , 12 5 ; Karstad, L. Lemaire, M. J Clin Microbiol, 38 11 ; 43 ref. Mars, M. H et al Airborne transmission of bovine herpesvirus 1 infections in calves under field conditions.
Veterinary Microbiology , 76 1 Veterinary Microbiology, 66 3 ; OIE, World Animal Health Information Database. Van, Oirschot, J.
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