Infectious Bovine Rhinotracheitis and Bovine Virus Diarrhea LOUIS E. NEWMAN Department ot Large Animal Surgery and Medicine Michigan State University, East Lansing 48824
INFECTIOUS BOVINE RHINOTRACHEITIS
I nfectious Pustular Vulvovaginitis ( I PV)
Infectious bovine rhinotracheitis (IBR), a herpesvirus, produces a disease of varying clinical manifestations. The disease is widespread in the United States and causes serious economic loss to the livestock industry.
Pustules and inflammation of the vulva and vagina cause a swollen vulva, vaginal discharge, tail switching, and depressed appetite. Lesions similar to those in the vagina occur on the penis and prepuce of infected bulls. This form of IBR may be transmitted b y natural breeding.
Transmission
The infectious bovine rhinotracheitis virus is transferred readily by contact and contamination. It is introduced most often to a herd by the addition of infected animals. It can be spread by obviously sick cattle or b y cattle shedding virus in the absence of clinical signs. Intermittent recurrence of virus shedding occasionally occurs long after apparent recovery, indicating that the virus exists as a latent infection. Forms of the Disease
Six clinical syndromes, in addition to the inapparent form of the disease, are associated with IBR virus infection. "'Rednose"
This is the respiratory form of IBR. It is characterized by fever, profuse nasal discharge, distressed breathing, decreased appetite, and depression. Outbreaks vary from mild to severe.
Inflammation of the brain is seen in calves up to the age of yearlings and causes depression, circling, progressive incoordination, coma, and death. This is not a common form of the disease in the United States. Neonatal Viremia
Calves less than 1 mo of age may develop a fatal, generalized disease characterized by fever, nasal discharge, and lesions of the upper gastrointestinal tract. Abortion
Abortion may be produced b y either natural infection or b y vaccination with some vaccines. Abortions typically occur 3 to 6 wk following vaccination or the clinical signs of the disease but may occur during an outbreak or up to 90 days following an outbreak. Abortions most often occur in the last trimester of gestation. Diagnosis
Conjunctivitis
This ocular form of the disease is characterized by inflamed mucous membranes of the eyes, tearing, and pus ip the corners of the eyes. White discoloration of the cornea occurs in some cases. Conjunctivitis may be the only manifestation of the disease, or it may be seen with the respiratory form.
Received September 24, 1975.
Encephalitis
The clinical signs and postmortem lesions of IBR may be sufficient for a tentative diagnosis. The laboratory may be able to confirm the diagnosis from the following specimens: nasal, ocular or vaginal swabs for virus isolation attempts, paired serum samples (one blood sample is collected early in the course of the disease and a second one is collected 3 wk later), aborted fetus and placenta, or frozen sections from tissues collected at postmortem examination for fluorescent antibody studies.
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Treatment
Antibiotic therapy to prevent or treat secondary bacterial infections (viruses are not susceptible to antibiotics and supportive treatment may be helpful. Prevention
Three types of vaccme are available for the prevention of IBR. Each vaccine has distinct advantages and disadvantages, and there are situations in which only one of the three might be feasible. The advice of a veterinarian is invaluable in establishing a vaccination program. He is familiar with the herd histroy, the local problem, and the vaccines currently available. Modified live virus (ML V). This is an intramuscular vaccine. Pregnant cattle should not be vaccinated because this vaccine can cause abortion. If adult vaccination is necessary, it should be accomplished following calving and not later than 3 wk prior to breeding. Beef calves may be vaccinated between 2 wk of age and 3 wk prior to weaning. They may be vaccinated upon arrival in the feedlot or after they become acclimated to the feedlot for 2 or more wk. Veterinary advice and supervision are recommended. All calves vaccinated prior to 6 mo of age should be given a second vaccination in the feedlot. Early vaccination may not produce satisfactory immunity and a second vaccination is necessary because colostrum from immune dams supplies a passive immunity to the calf which may last until 4 to 6 mo of age. The antibodies supplied by this passive immunity neutralize the virus particles contained in the vaccine. Replacement heifers should be vaccinated or given a second vaccination between 6 and 12 mo of age and not later than 3 wk prior to breeding. A single vaccination at 6 mo of age or older probably confers adequate immunity for the lifetime of most cattle. A second vaccination, or annual revaccination, may be indicated in some herds. Do not vaccinate in the face of severe stress. Vaccination and handling are an additional stress. Neutralizing antibodies are not in the blood until 9 days following vaccination. It takes at least this tong for immunity to develop. Many veterinarians prefer to maintain vaccinated animals separate from pregnant cattle Journal of Dairy Science Vol. 59, No. 6
for 3 wk following vaccination. lntranasal IBR vaccine. This is a modified live virus vaccine which is sprayed into the nasal cavity. A local response to the vaccine in the nasal passages results in early immunity. Calves may be vaccinated as early as 2 days of age. This vaccine has been approved for use in pregnant cattle. The duration of immunity is not known. Annual revaccination is recommended. InactivatedlBR vaccine. This is a "killed" vaccine. This vaccine eliminates the possibility of abortion, vaccine-caused illness, and shedding vaccine virus. Two injections are required, and the duration of immunity is unknown. Thus, annual revaccination is recommended. In a small percentage of vaccinated cattle, severe and sometimes fatal allergic reactions have occurred. BOVINE VIRUS DIARRHEA
Bovine virus diarrhea (BVD), a togavirus, causes an acute or chronic disease of cattle characterized by fever, diarrhea, and erosions of the mucous membranes of the digestive tract. This disease occurs throughout the United States, and the likelihood of exposure is high. However, most exposed cattle have a mild or unobserved infection (rarely recognized as BVD) which results in immunity. If first exposure occurs during the first 2 trimesters of pregnancy, abortion or fetal damage may result. Transmission
Bovine virus diarrhea is caused by a hardy virus readily transferred on contaminated boots, feed sacks, and equipment. The BVD virus spreads rapidly, and all animals in a herd may be exposed by the time the disease first is recognized. Forms of the Disease
Cattle infected with BVD virus may respond with a variety of clinical signs and lesions. An inapparent or mild infection is also common. Bovine virus diarrhea usually occurs as a sudden outbreak infecting most of the herd. However, only a small percent of the herd may have clinical signs such as: fever, depression, and decreased appetite; nasal discharge, ocular discharge, rapid respiration and cough; exces-
SYMPOSIUM: BIOLOGICAL AGENTS CAUSING INFECTIONS IN DAIRY CATTLE sive salivation; diarrhea; and erosions of the lips, mouth, and gastrointestinal tract. Less common clinical signs include: lameness [cracking between the toes (interdigital lesions), swelling and erosions at the top of the hoof (coronary band), chronic founder following recovery]; a corneal opacity (as in pinkeye) occurring several days after the onset of illness; a rough, dry scruffy skin (hyperkeratosis); and erosions or scabs on the vulva. Bovine virus diarrhea frequently is diagnosed as a respiratory disease, with clinical signs of fever, rapid respiration, cough, nasal discharge, and crusted nose. There may be no oral lesions, and diarrhea may be minimal or absent. A sporadic fatal form of mucosal disease is believed to be the result o f the inability of the infected animal to produce adequate protective antibodies to the BVD virus. This form of the disease also may occur rarely following vaccination. The fatal form of mucosal disease may progress slowly, taking weeks to months in its course through a herd. Only a few animals are sick at any one time. Early signs include a mucous ocular and nasal discharge, depression and loss of appetite followed b y severe erosions of the muzzle and mouth, a watery diarrhea and dehydration. Death usually occurs within 10 days, but chronic cases may linger several months. The BVD virus has a severe effect upon the fetus even though the infection may be so mild as to go unnoticed in the pregnant cow. Abortions may occur 3 to 6 wk or longer following infection or vaccination. Newborn calves may show weakness, incoordination, lesions of the mouth, eye defects, diarrhea, stunted growth, and high mortality. Defective development of the cerebellum of the brain and cataracts of the lens of the eye often are seen in calves born from dams infected during mid-gestation.
Diagnosis
The clinical signs and lesions often suggest bovine virus diarrhea, but postmortem examination and laboratory tests may be necessary to establish a definitive diagnosis. The following specimens are used in laboratory diagnosis: blood samples taken at the time of the acute disease and again 3 wk later (paired serum sampies); the aborted fetus and placenta; ocular (eye), nasal (nose), and rectal swabs, tissues
1181
(spleen, intestine, lymph node) and citrated blood for virus isolation; or frozen tissue sections examined utilizing a fluorescent antibody technique. Bovine virus diarrhea must be differentiated from conditions which cause mucosal erosions or necrosis (rinderpest, the vesicular diseases, malignant catarrhal fever, bovine bluetongue, bovine papular stomatitis), conditions which cause diarrhea (rinderpest, winter dysentery, salmonellosis, coccidiosis, and some toxicoses), and conditions which cause nasal discharge and rapid breathing (rinderpest, vesicular disease, malignant catarrhal fever, bovine btuetongue, and IBR). Treatment
There is no specific treatment for BVD. However, antibiotics, sulfonamides, astringents, and supportive therapy may be indicated. Prevention
Prevention of BVD is dependent upon developing an immune cow herd. The only products currently available are modified live virus vaccines for intramuscular use. The BVD virus spreads rapidly, and vaccination is not recommended during an acute outbreak. Pregnant cattle should not be vaccinated. If adult vaccination is necessary, it should be accomplished following calving and at least 3 wk prior to breeding. Calves may be vaccinated between 1 day of age and 3 wk prior to weaning. They may be vaccinated upon arrival in the feedlot or after they become acclimated to the feedlot for 2 or more wk. Veterinary consultation and supervision are important to a successful vaccination program. (Occasional severe post-vaccination disease occurs, and there is some controversy over the use o f this vaccine.) All calves vaccinated prior to weaning should be given a second vaccination in the feedlot. Colostrum from immune dams supplies a passive immunity to the calf which may last until 5 to 9 mo of age. This is the reason early vaccination may not produce satisfactory immunity and a second vaccination is necessary. Replacement heifers should be vaccinated or given a second vaccination between 9 and 12 mo of age and not later than 3 wk prior to Journal of Dairy Science Vol. 59, No. 6
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NEWMAN
bred should not be vaccinated with intramuscular IBR or BVD modified live virus vaccines. (Intranasal IBR vaccine is approved for pregnant cattle.) 9. Passive immunity acquired by ingestion of colostrum from an immune cow can protect against early calfhood infections but also may interfere with successful vaccination of calves. (Intranasal IBR vaccine may be effective in calves as young as 2 days of age even though they have colostral antibodies, b u t additional studies are needed.) 10. Vaccination during herd outbreaks is not recommended. 11. Vaccination of adult cattle with intramuscular modified live virus vaccine is generally not recommended. 12. Vaccination of cattle within 3 wk of the time they are to be bred is not recommended. 13. Calfhood vaccination is recommended between 9 and 12 mo of age. Colostrally acGENERALIZATIONS WHICH AFFECT IBR quired immunity disappears at varying ages: A N D BVD VACCINATION RECOMMENDATIONS IBR, 4 to 6 mo of age;BVD, 5 to 9 mo of age. The duration of modified-live-virus vaccine1. The IBR and BVD viruses are distributed induced immunity may be life-long in most catwidely and established permanently in cattle in tle. Calfhood vaccination provides protection this country. A n u m b e r of surveys have shown prior to breeding age and avoids vaccination over 35% of the cattle to have circulating antijust prior to breeding. A good calfhood vaccinabodies to the IBR virus and over 55% of the tion program involving all replacement heifers cattle to have circulating antibodies to the BVD will result in an immune herd without adult virus. vaccination. 2. Most cattle kept for breeding purposes 14. The livestock owner should depend on eventually will be exposed to one or both of the advice of the local veterinarian. Different these viruses. 3. Infection may produce clinical illness, vaccination programs and vaccines are indicated or it may be so mild as to be unobserved. in different situations. 4. Infection can result in abortion, b u t not EPITOME all animals infected during pregnancy abort. Abortions and congenital anomalies (calves Replacement heifers for both dairy and beef with abnormalities at birth) may follow subclin- cattle herds should be vaccinated for IBR and ical infection. BVD with modified live virus vaccines between 5. Pregnant cattle will not abort if they are 9 and 12 mo of age. immune at the time of exposure. The herd veterinarian is the best qualified 6. No vaccination procedure is completely person to give advice and help in diagnosing and safe or 100% effective. treating infectious diseases, establishing a vac7. Immunity following successful vaccina- cination program, determining the feasibility of tion with intramuscular modified live virus vac- vaccination, and selecting the vaccine. cine or natural infection with either IBR or BVD may be lifelong in many cattle. (InactivaREFERENCES ted IBR vaccines require annual vaccination. 1 Archbald, L F. 1974. Isolation of bovine virus diaIntranasal vaccine immunity trials will not be rrhea virus from the uterocervical secretion of a completed for several years, and annual vaccinarepeat-breeder cow. VM/SAC 69:1540. 2 Bordt, D. E. 1975. Bovine virus diarrhea vaction is recommended.) cines. A comparison of two virus strains. VM/ 8. Pregnant cattle or cattle about to be
breeding. A single vaccination at this age, or older, probably confers adequate immunity for the productive life of most cows. A second vaccination may be considered at the discretion of the herd veterinarian. Do not vaccinate in the face of severe stress. Vaccination and handling are additional stresses. Circulating antibodies may not be in the blood until 21 days after vaccination. It may take this long for immunity to develop. Replacement dairy heifers should be vaccinated at 9 to 12 mo of age. The heifer is old enough at 9 mo of age so that she will no longer have any colostral immunity and a single vaccination will probably confer lifelong immunity. There is an increased margin of safety because vaccination at 12 mo of age is still 2 mo or more before the heifer will be bred.
Journal of Dairy Science Vol. 59, No. 6
SYMPOSIUM: BIOLOGICAL AGENTS CAUSING INFECTIONS IN DAIRY C A T T L E SAC 70:441. 3 Butler, J. E. 1971. Review o f the bovine i m m u n o globulins. S y m p o s i u m : The bovine i m m u n e system. J. Dairy Sci. 54:1315. 4 Corner, A. H., A. S. Greig, and D. P. Hill. 1967. A histological s t u d y of the effects o f the herpesvirus o f infectious bovine rhinotracheitis in the lactating bovine m a m m a r y gland. Can. J. Comp. Med. Vet. Sci. 31:320. 5 Cottral, G. E. 1972. Diagnosis o f bovine vesicular diseases. J. Amer. Vet. Med. Ass. 161:1293. 6 Curtis, R. A., and A. Angulo. 1974. A field trial to evaluate an intranasal infectious bovine rhinotracheitis vaccine. Can. Vet. J. 15: 327. 7 Darcel, C. le Q., and W. J. Dorward. 1975. Recovery of infectious bovine rhinotracheitis virus following corticosteroid t r e a t m e n t of vaccinated animals. Can. Vet. J. 16:87. 8 Fernelius. A. L., L. G. Classick, and R. L. Smith. 1972. Evaluation of 13-propionlactone-inactlvatedand chloroform-treated-virus vaccines against bovine viral diarrhea-mucosal disease. Amer. J. Vet. Res. 33:1421. 9 Gourlay, R. N., and E. J. Stott. 1974. Isolation of Mycoplasma agalactiae var boris and infectious bovine rhinotracheitis virus from an outbreak of mastitis in France. Vet. Rec. 7: 534. 10 Kahrs, R. F. 1971. Serologic testing in the diagnosis of virus diseases of cattle. The Bovine Practitioner November: 50. 11 Kahrs, R. F. 1974. Rational basis for an i m m u n i zation program against t h e c o m m o n diseases of the bovine respiratory tract. Can. Vet. J. 15:252. 12 Kahrs, R. F. 1971. Differential diagnosis o f bovine viral diarrhea-mucosal disease. J. Amer. Vet. Med. Ass. 159:1383. 13 Kahrs, R. F., F. W. Scott, and A. de Lahunta. 1970. Congenital cerebellar hypoplasia and ocular defects in calves following bovine viral diarrheamucosal disease infection in pregnant cattle. J.
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Amer. Vet. Med. Ass. 156:1443. 14 Kahrs, R. F., F. W. Scott, and A. de Lahunta. 1970. Bovine viral diarrhea-mucosal disease, abortion, and congenital cerebellar hypoplasia in a dairy herd. J. Amer. Vet. Med. Ass. 156:851. 15 Kaminjolo, J. S., P. N. Nyaga, J. K. Omuse, and E. R. Mutiga. 1975. Infectious bovine rhinotracheitis-infectious pustular vulvovaginitis viral isolates from cattle with epididymitis and vaginitis. Amer. J. Vet. IRes. 36:123. 16 Kendfick, J. W., and C. E. Franti. 1974. Bovine viral diarrhea: Decay of colostrum-conferred antib o d y in the calf. Amer. J. Vet. Res. 35:589. 17 Phillips, R. M., W. P. Heuschele, and J. D. Todd. 1975. Evaluation of a bovine viral diarrhea vaccine produced in a porcine kidney cell line. Amer. J. Vet. Res. 36:135. 18 Roberts, A. W., and R. G. Carter. 1972. Simplified and economical cell culture techniques for laboratories beginning clinical veterinary virology. J. Amer. Vet. Med. Ass. 164:413. 19 Searl, R. C. I.B.R., B.V.D., P.I.3, mucosal disease: A clinician's observations. Biochem. Rev. 32. 20 Steves, F. E., and W. P. Heuschele. 1964. IBR abortion and its control. VM/SAC February:164. 21 Todd, J. D. 1974. Development o f intranasal vaccination for the immunization of cattle against bovine rhinotracheitis. Can. Vet. J. 15:257. 22 Todd, J. D. 1971. Bovine i m m u n e response to respiratory infections of viral etiology. Symposium: The bovine i m m u n e system. J. Dairy Sci. 54:1334. 23 Todd, J. D., J. F. Volence, and 1. M. Paton. 1971. Intranasal vaccination against infectious bovine rhinotracheitis: Studies on early onset of protection and use of the vaccine in pregnant cows. J. Amer. Vet. Med. Ass. 159:1370. 24 Zemjanis, R. 1974. Vaccination for reproductive efficiency in cattle. J. Amer. Vet. Med. Ass. 165: 689.
Journal of Dairy Science Vol. 59, No. 6
INFECTIOUS BOVINE RHINOTRACHEITIS
I nfectious Pustular Vulvovaginitis ( I PV)
Infectious bovine rhinotracheitis (IBR), a herpesvirus, produces a disease of varying clinical manifestations. The disease is widespread in the United States and causes serious economic loss to the livestock industry.
Pustules and inflammation of the vulva and vagina cause a swollen vulva, vaginal discharge, tail switching, and depressed appetite. Lesions similar to those in the vagina occur on the penis and prepuce of infected bulls. This form of IBR may be transmitted b y natural breeding.
Transmission
The infectious bovine rhinotracheitis virus is transferred readily by contact and contamination. It is introduced most often to a herd by the addition of infected animals. It can be spread by obviously sick cattle or b y cattle shedding virus in the absence of clinical signs. Intermittent recurrence of virus shedding occasionally occurs long after apparent recovery, indicating that the virus exists as a latent infection. Forms of the Disease
Six clinical syndromes, in addition to the inapparent form of the disease, are associated with IBR virus infection. "'Rednose"
This is the respiratory form of IBR. It is characterized by fever, profuse nasal discharge, distressed breathing, decreased appetite, and depression. Outbreaks vary from mild to severe.
Inflammation of the brain is seen in calves up to the age of yearlings and causes depression, circling, progressive incoordination, coma, and death. This is not a common form of the disease in the United States. Neonatal Viremia
Calves less than 1 mo of age may develop a fatal, generalized disease characterized by fever, nasal discharge, and lesions of the upper gastrointestinal tract. Abortion
Abortion may be produced b y either natural infection or b y vaccination with some vaccines. Abortions typically occur 3 to 6 wk following vaccination or the clinical signs of the disease but may occur during an outbreak or up to 90 days following an outbreak. Abortions most often occur in the last trimester of gestation. Diagnosis
Conjunctivitis
This ocular form of the disease is characterized by inflamed mucous membranes of the eyes, tearing, and pus ip the corners of the eyes. White discoloration of the cornea occurs in some cases. Conjunctivitis may be the only manifestation of the disease, or it may be seen with the respiratory form.
Received September 24, 1975.
Encephalitis
The clinical signs and postmortem lesions of IBR may be sufficient for a tentative diagnosis. The laboratory may be able to confirm the diagnosis from the following specimens: nasal, ocular or vaginal swabs for virus isolation attempts, paired serum samples (one blood sample is collected early in the course of the disease and a second one is collected 3 wk later), aborted fetus and placenta, or frozen sections from tissues collected at postmortem examination for fluorescent antibody studies.
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NEWMAN
Treatment
Antibiotic therapy to prevent or treat secondary bacterial infections (viruses are not susceptible to antibiotics and supportive treatment may be helpful. Prevention
Three types of vaccme are available for the prevention of IBR. Each vaccine has distinct advantages and disadvantages, and there are situations in which only one of the three might be feasible. The advice of a veterinarian is invaluable in establishing a vaccination program. He is familiar with the herd histroy, the local problem, and the vaccines currently available. Modified live virus (ML V). This is an intramuscular vaccine. Pregnant cattle should not be vaccinated because this vaccine can cause abortion. If adult vaccination is necessary, it should be accomplished following calving and not later than 3 wk prior to breeding. Beef calves may be vaccinated between 2 wk of age and 3 wk prior to weaning. They may be vaccinated upon arrival in the feedlot or after they become acclimated to the feedlot for 2 or more wk. Veterinary advice and supervision are recommended. All calves vaccinated prior to 6 mo of age should be given a second vaccination in the feedlot. Early vaccination may not produce satisfactory immunity and a second vaccination is necessary because colostrum from immune dams supplies a passive immunity to the calf which may last until 4 to 6 mo of age. The antibodies supplied by this passive immunity neutralize the virus particles contained in the vaccine. Replacement heifers should be vaccinated or given a second vaccination between 6 and 12 mo of age and not later than 3 wk prior to breeding. A single vaccination at 6 mo of age or older probably confers adequate immunity for the lifetime of most cattle. A second vaccination, or annual revaccination, may be indicated in some herds. Do not vaccinate in the face of severe stress. Vaccination and handling are an additional stress. Neutralizing antibodies are not in the blood until 9 days following vaccination. It takes at least this tong for immunity to develop. Many veterinarians prefer to maintain vaccinated animals separate from pregnant cattle Journal of Dairy Science Vol. 59, No. 6
for 3 wk following vaccination. lntranasal IBR vaccine. This is a modified live virus vaccine which is sprayed into the nasal cavity. A local response to the vaccine in the nasal passages results in early immunity. Calves may be vaccinated as early as 2 days of age. This vaccine has been approved for use in pregnant cattle. The duration of immunity is not known. Annual revaccination is recommended. InactivatedlBR vaccine. This is a "killed" vaccine. This vaccine eliminates the possibility of abortion, vaccine-caused illness, and shedding vaccine virus. Two injections are required, and the duration of immunity is unknown. Thus, annual revaccination is recommended. In a small percentage of vaccinated cattle, severe and sometimes fatal allergic reactions have occurred. BOVINE VIRUS DIARRHEA
Bovine virus diarrhea (BVD), a togavirus, causes an acute or chronic disease of cattle characterized by fever, diarrhea, and erosions of the mucous membranes of the digestive tract. This disease occurs throughout the United States, and the likelihood of exposure is high. However, most exposed cattle have a mild or unobserved infection (rarely recognized as BVD) which results in immunity. If first exposure occurs during the first 2 trimesters of pregnancy, abortion or fetal damage may result. Transmission
Bovine virus diarrhea is caused by a hardy virus readily transferred on contaminated boots, feed sacks, and equipment. The BVD virus spreads rapidly, and all animals in a herd may be exposed by the time the disease first is recognized. Forms of the Disease
Cattle infected with BVD virus may respond with a variety of clinical signs and lesions. An inapparent or mild infection is also common. Bovine virus diarrhea usually occurs as a sudden outbreak infecting most of the herd. However, only a small percent of the herd may have clinical signs such as: fever, depression, and decreased appetite; nasal discharge, ocular discharge, rapid respiration and cough; exces-
SYMPOSIUM: BIOLOGICAL AGENTS CAUSING INFECTIONS IN DAIRY CATTLE sive salivation; diarrhea; and erosions of the lips, mouth, and gastrointestinal tract. Less common clinical signs include: lameness [cracking between the toes (interdigital lesions), swelling and erosions at the top of the hoof (coronary band), chronic founder following recovery]; a corneal opacity (as in pinkeye) occurring several days after the onset of illness; a rough, dry scruffy skin (hyperkeratosis); and erosions or scabs on the vulva. Bovine virus diarrhea frequently is diagnosed as a respiratory disease, with clinical signs of fever, rapid respiration, cough, nasal discharge, and crusted nose. There may be no oral lesions, and diarrhea may be minimal or absent. A sporadic fatal form of mucosal disease is believed to be the result o f the inability of the infected animal to produce adequate protective antibodies to the BVD virus. This form of the disease also may occur rarely following vaccination. The fatal form of mucosal disease may progress slowly, taking weeks to months in its course through a herd. Only a few animals are sick at any one time. Early signs include a mucous ocular and nasal discharge, depression and loss of appetite followed b y severe erosions of the muzzle and mouth, a watery diarrhea and dehydration. Death usually occurs within 10 days, but chronic cases may linger several months. The BVD virus has a severe effect upon the fetus even though the infection may be so mild as to go unnoticed in the pregnant cow. Abortions may occur 3 to 6 wk or longer following infection or vaccination. Newborn calves may show weakness, incoordination, lesions of the mouth, eye defects, diarrhea, stunted growth, and high mortality. Defective development of the cerebellum of the brain and cataracts of the lens of the eye often are seen in calves born from dams infected during mid-gestation.
Diagnosis
The clinical signs and lesions often suggest bovine virus diarrhea, but postmortem examination and laboratory tests may be necessary to establish a definitive diagnosis. The following specimens are used in laboratory diagnosis: blood samples taken at the time of the acute disease and again 3 wk later (paired serum sampies); the aborted fetus and placenta; ocular (eye), nasal (nose), and rectal swabs, tissues
1181
(spleen, intestine, lymph node) and citrated blood for virus isolation; or frozen tissue sections examined utilizing a fluorescent antibody technique. Bovine virus diarrhea must be differentiated from conditions which cause mucosal erosions or necrosis (rinderpest, the vesicular diseases, malignant catarrhal fever, bovine bluetongue, bovine papular stomatitis), conditions which cause diarrhea (rinderpest, winter dysentery, salmonellosis, coccidiosis, and some toxicoses), and conditions which cause nasal discharge and rapid breathing (rinderpest, vesicular disease, malignant catarrhal fever, bovine btuetongue, and IBR). Treatment
There is no specific treatment for BVD. However, antibiotics, sulfonamides, astringents, and supportive therapy may be indicated. Prevention
Prevention of BVD is dependent upon developing an immune cow herd. The only products currently available are modified live virus vaccines for intramuscular use. The BVD virus spreads rapidly, and vaccination is not recommended during an acute outbreak. Pregnant cattle should not be vaccinated. If adult vaccination is necessary, it should be accomplished following calving and at least 3 wk prior to breeding. Calves may be vaccinated between 1 day of age and 3 wk prior to weaning. They may be vaccinated upon arrival in the feedlot or after they become acclimated to the feedlot for 2 or more wk. Veterinary consultation and supervision are important to a successful vaccination program. (Occasional severe post-vaccination disease occurs, and there is some controversy over the use o f this vaccine.) All calves vaccinated prior to weaning should be given a second vaccination in the feedlot. Colostrum from immune dams supplies a passive immunity to the calf which may last until 5 to 9 mo of age. This is the reason early vaccination may not produce satisfactory immunity and a second vaccination is necessary. Replacement heifers should be vaccinated or given a second vaccination between 9 and 12 mo of age and not later than 3 wk prior to Journal of Dairy Science Vol. 59, No. 6
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NEWMAN
bred should not be vaccinated with intramuscular IBR or BVD modified live virus vaccines. (Intranasal IBR vaccine is approved for pregnant cattle.) 9. Passive immunity acquired by ingestion of colostrum from an immune cow can protect against early calfhood infections but also may interfere with successful vaccination of calves. (Intranasal IBR vaccine may be effective in calves as young as 2 days of age even though they have colostral antibodies, b u t additional studies are needed.) 10. Vaccination during herd outbreaks is not recommended. 11. Vaccination of adult cattle with intramuscular modified live virus vaccine is generally not recommended. 12. Vaccination of cattle within 3 wk of the time they are to be bred is not recommended. 13. Calfhood vaccination is recommended between 9 and 12 mo of age. Colostrally acGENERALIZATIONS WHICH AFFECT IBR quired immunity disappears at varying ages: A N D BVD VACCINATION RECOMMENDATIONS IBR, 4 to 6 mo of age;BVD, 5 to 9 mo of age. The duration of modified-live-virus vaccine1. The IBR and BVD viruses are distributed induced immunity may be life-long in most catwidely and established permanently in cattle in tle. Calfhood vaccination provides protection this country. A n u m b e r of surveys have shown prior to breeding age and avoids vaccination over 35% of the cattle to have circulating antijust prior to breeding. A good calfhood vaccinabodies to the IBR virus and over 55% of the tion program involving all replacement heifers cattle to have circulating antibodies to the BVD will result in an immune herd without adult virus. vaccination. 2. Most cattle kept for breeding purposes 14. The livestock owner should depend on eventually will be exposed to one or both of the advice of the local veterinarian. Different these viruses. 3. Infection may produce clinical illness, vaccination programs and vaccines are indicated or it may be so mild as to be unobserved. in different situations. 4. Infection can result in abortion, b u t not EPITOME all animals infected during pregnancy abort. Abortions and congenital anomalies (calves Replacement heifers for both dairy and beef with abnormalities at birth) may follow subclin- cattle herds should be vaccinated for IBR and ical infection. BVD with modified live virus vaccines between 5. Pregnant cattle will not abort if they are 9 and 12 mo of age. immune at the time of exposure. The herd veterinarian is the best qualified 6. No vaccination procedure is completely person to give advice and help in diagnosing and safe or 100% effective. treating infectious diseases, establishing a vac7. Immunity following successful vaccina- cination program, determining the feasibility of tion with intramuscular modified live virus vac- vaccination, and selecting the vaccine. cine or natural infection with either IBR or BVD may be lifelong in many cattle. (InactivaREFERENCES ted IBR vaccines require annual vaccination. 1 Archbald, L F. 1974. Isolation of bovine virus diaIntranasal vaccine immunity trials will not be rrhea virus from the uterocervical secretion of a completed for several years, and annual vaccinarepeat-breeder cow. VM/SAC 69:1540. 2 Bordt, D. E. 1975. Bovine virus diarrhea vaction is recommended.) cines. A comparison of two virus strains. VM/ 8. Pregnant cattle or cattle about to be
breeding. A single vaccination at this age, or older, probably confers adequate immunity for the productive life of most cows. A second vaccination may be considered at the discretion of the herd veterinarian. Do not vaccinate in the face of severe stress. Vaccination and handling are additional stresses. Circulating antibodies may not be in the blood until 21 days after vaccination. It may take this long for immunity to develop. Replacement dairy heifers should be vaccinated at 9 to 12 mo of age. The heifer is old enough at 9 mo of age so that she will no longer have any colostral immunity and a single vaccination will probably confer lifelong immunity. There is an increased margin of safety because vaccination at 12 mo of age is still 2 mo or more before the heifer will be bred.
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SYMPOSIUM: BIOLOGICAL AGENTS CAUSING INFECTIONS IN DAIRY C A T T L E SAC 70:441. 3 Butler, J. E. 1971. Review o f the bovine i m m u n o globulins. S y m p o s i u m : The bovine i m m u n e system. J. Dairy Sci. 54:1315. 4 Corner, A. H., A. S. Greig, and D. P. Hill. 1967. A histological s t u d y of the effects o f the herpesvirus o f infectious bovine rhinotracheitis in the lactating bovine m a m m a r y gland. Can. J. Comp. Med. Vet. Sci. 31:320. 5 Cottral, G. E. 1972. Diagnosis o f bovine vesicular diseases. J. Amer. Vet. Med. Ass. 161:1293. 6 Curtis, R. A., and A. Angulo. 1974. A field trial to evaluate an intranasal infectious bovine rhinotracheitis vaccine. Can. Vet. J. 15: 327. 7 Darcel, C. le Q., and W. J. Dorward. 1975. Recovery of infectious bovine rhinotracheitis virus following corticosteroid t r e a t m e n t of vaccinated animals. Can. Vet. J. 16:87. 8 Fernelius. A. L., L. G. Classick, and R. L. Smith. 1972. Evaluation of 13-propionlactone-inactlvatedand chloroform-treated-virus vaccines against bovine viral diarrhea-mucosal disease. Amer. J. Vet. Res. 33:1421. 9 Gourlay, R. N., and E. J. Stott. 1974. Isolation of Mycoplasma agalactiae var boris and infectious bovine rhinotracheitis virus from an outbreak of mastitis in France. Vet. Rec. 7: 534. 10 Kahrs, R. F. 1971. Serologic testing in the diagnosis of virus diseases of cattle. The Bovine Practitioner November: 50. 11 Kahrs, R. F. 1974. Rational basis for an i m m u n i zation program against t h e c o m m o n diseases of the bovine respiratory tract. Can. Vet. J. 15:252. 12 Kahrs, R. F. 1971. Differential diagnosis o f bovine viral diarrhea-mucosal disease. J. Amer. Vet. Med. Ass. 159:1383. 13 Kahrs, R. F., F. W. Scott, and A. de Lahunta. 1970. Congenital cerebellar hypoplasia and ocular defects in calves following bovine viral diarrheamucosal disease infection in pregnant cattle. J.
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Amer. Vet. Med. Ass. 156:1443. 14 Kahrs, R. F., F. W. Scott, and A. de Lahunta. 1970. Bovine viral diarrhea-mucosal disease, abortion, and congenital cerebellar hypoplasia in a dairy herd. J. Amer. Vet. Med. Ass. 156:851. 15 Kaminjolo, J. S., P. N. Nyaga, J. K. Omuse, and E. R. Mutiga. 1975. Infectious bovine rhinotracheitis-infectious pustular vulvovaginitis viral isolates from cattle with epididymitis and vaginitis. Amer. J. Vet. IRes. 36:123. 16 Kendfick, J. W., and C. E. Franti. 1974. Bovine viral diarrhea: Decay of colostrum-conferred antib o d y in the calf. Amer. J. Vet. Res. 35:589. 17 Phillips, R. M., W. P. Heuschele, and J. D. Todd. 1975. Evaluation of a bovine viral diarrhea vaccine produced in a porcine kidney cell line. Amer. J. Vet. Res. 36:135. 18 Roberts, A. W., and R. G. Carter. 1972. Simplified and economical cell culture techniques for laboratories beginning clinical veterinary virology. J. Amer. Vet. Med. Ass. 164:413. 19 Searl, R. C. I.B.R., B.V.D., P.I.3, mucosal disease: A clinician's observations. Biochem. Rev. 32. 20 Steves, F. E., and W. P. Heuschele. 1964. IBR abortion and its control. VM/SAC February:164. 21 Todd, J. D. 1974. Development o f intranasal vaccination for the immunization of cattle against bovine rhinotracheitis. Can. Vet. J. 15:257. 22 Todd, J. D. 1971. Bovine i m m u n e response to respiratory infections of viral etiology. Symposium: The bovine i m m u n e system. J. Dairy Sci. 54:1334. 23 Todd, J. D., J. F. Volence, and 1. M. Paton. 1971. Intranasal vaccination against infectious bovine rhinotracheitis: Studies on early onset of protection and use of the vaccine in pregnant cows. J. Amer. Vet. Med. Ass. 159:1370. 24 Zemjanis, R. 1974. Vaccination for reproductive efficiency in cattle. J. Amer. Vet. Med. Ass. 165: 689.
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