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Anaplasmosis Vaccines
BOVINE VACCINES AND HERD VACCINATION PROGRAMS
247
immunity are important in protecting against salmonella and other facultative intracellular bacteria. 3 •4 The best hope for a satisfactory future vaccine, therefore, appears to be one that stimulates both humoral and cellular immunity in neonatal calves as well as in mature animals. Experimental, genetically-altered, modified-live salmonella vaccines elicit both humoral immunity and eMI in calves and protect against virulent challenge. 5 .
REFERENCES 1. Smith BP, Habasha FG, Reina-Guerra M, et al: Immunization of calves against salmonellosis. Am J Vet Res 41:1947-1951,1980 2. Spier S, Smith BP, Dilling G, et al: ELISA response to vaccination with a killed salmonella bacterin. Unpublished data; in preparation 3. Venneman MR, Berry LJ: Cell-mediated resistance induced with immunogenic preparations of Salmonella typhimurium. Infec Immun 4:381-382, 1971 4. Habasha FG, Smith BP, Schwartz L, et al: Correlation of macrophage migrationinhibition factor and protection from challenge exposure in calves vaccinated with Salmonella typhimurium. Am J Vet Res 46:1415-1421, 1985 5. Smith BP, Reina-Guerra M, Stocker BAD, et al: Aromatic-dependent Salmonella dublin as a parenteral modified-live vaccine for calves. Am J Vet Res 45:2231-2235, 1984
MISCELLANEOUS BOVINE RICKETTSIAL, BACTERIAL, AND VIRAL DISEASE VACCINES Anaplasmosis Vaccines Anaplasma marginale causes fever, anorexia, anemia, icterus, weakness, abortions, weight loss, emaciation, depressed testicular function in bulls, and sometimes death, especially in cattle over 2 years of age. Cattle under 12 months of age become infected but seldom manifest clinical signs of disease. In cattle over 36 months of age, disease is usually severe, and a case fatality rate of 30 to 50% is to be expected. Cattle between 12 and 36 months of age are variably affected. 1 ,2 General Considerations Within endemic areas, a high proportion of adult cattle may be immune carriers. 3 Calves born to immune dams are passively immune and resist infection until 1 to 6 months of age. 4 Within areas where anaplasmosis is endemic, the pattern of disease that is generally observed will be dependent upon (1) the prevalence of the carrier state and (2) the biological vectors that are present. Within areas where tick transmission occurs, most adult cattle are immune carriers, and clinical disease occurs only sporadically. 3 Most cattle within such areas become permanently infected when they are between 6 and 12 months of age and do not evidence clinical disease. 5 •6 The exception is when susceptible adults are introduced from nonendemic areas. In that event, high morbidity and mortality rates are to be expected. 5 Vaccination of such animals, at least 42 days prior to grazing endemic areas, is imperative. 7 Within endemic areas where tick transmission does not occur, most
248
CHARLES
A.
HJERPE
adult animals will be susceptible. Severe seasonal disease outbreaks may occur in association with increases in the populations of biting insects. 2•5 A minimum of 10 tabanid fly bites are required to accomplish mechanical transmission from an acutely affected bovine to a susceptible one. 8 Tabanid flies do not remain infective for more than 2 hours after feeding on an infected animal. 8 It has been shown that mechanical disease transmission by biting insects can be prevented if carrier cattle are not grazed within 1 to 2 miles of susceptible cattle. 9 •10 Anaplaz (Fort Dodge Laboratories, Fort Dodge, IA 50501). Anaplaz (R) is an inactivated vaccine. General recommendations for its use are summarized (see Table 9). Anaplaz is recommended for subcutaneous administration in two doses, not less than 4 weeks apart. Protection is achieved by 2 weeks following administration of the immunizing dose. 7 A single booster dose may be administered 12 months following the immunizing dose. Vaccinated cattle are immune for 12 months after primary vaccination and for 24 additional months after booster vaccination. 2 Vaccination prevents clinical disease but does not prevent infection. 2 Within endemic areas where tick transmission occurs, most (but not necessarily all) vaccinated cattle become immune carriers prior to expiration of vaccinal immunity. Anaplaz contains red cell antigens that can stimulate antierythrocyte antibody production in cows that are negative for the respective red cell antigens present in the vaccine. These antibodies are concentrated in the colostrum of parturient cows and heifers and may cause neonatal isoerythrolysis if ingested in sufficient quantities by newborn calves that have the same RBC type as is present in the vaccine. 11 This problem is minimized by (1) administering Anaplaz to heifers and cows at a time when they are not pregnant (so that by the time they are calving, their antierythrocyte antibody titers will have declined to low levels) and (2) by administering only a single-booster dose of vaccine to any particular cow during her lifetime. 12 Repeated boostering (at any time, but especially in late pregnancy) increases the risk of neonatal isoerythrolysis. 12 Bulls can be safely maintained immune for life by repeated boostering at 12- to 24-month intervals. 2 •12 The vaccine label insert warns that complement-fixing antibodies develop and persist for up to 4 months following administration of the second (immunizing) dose. This must be kept in mind when deciding on a program for control of anaplasmosis in cattle that are destined for interstate shipment or export. Anaplaz is the vaccine of choice for (1) administration to cattle over 24-months of age and (2) for use in the face of an outbreak. In the latter situation, Anaplaz is administered twice, with a 4-week interval, each time in combination with an injection of standard oxytetracycline hydrochloride, in a dose of 6.6 mg per kg of body weight. Parenteral administration of oxytetracycline in this dosage to an animal that is incubating the disease will delay the onset of clinical signs by approximately 28 days each time that it is done. This provides the 6 weeks of disease-free time that is required to achieve vaccinal immunity in exposed cattle. 13 However, because of the risk of neonatal isoerythrolysis,
BOVINE VACCINES AND HERD VACCINATION PROGRAMS
249
it may be best to segregate cattle that are pregnant 5 months or more, control their disease with chemotherapy, and postpone vaccination until after they have calved. 12 Anavac (BioLOGIC Laboratories, Davis, CA 95616) Anavac is a modified-live vaccine and is licensed for use only in California. 6 It utilizes a strain of A. marginale that has been modified by passage in sheep. General recommendations for its use are summarized (see Table 9). The vaccine must be stored in liquid nitrogen or on dry ice. It is recommended by the manufacturer for intramuscular administration in a single dose to healthy cattle between 1 month and 2 years of age. If carrier cows are known to be present in the herd, administration should be delayed until after 6 months of age, in order to ensure that passive antibodies do not interfere with active immunity. 4 If the vaccine is administered to cattle over 2 years of age, anemia, severe clinical disease, and death may occur, especially in bulls and heavily lactating cows. These cows may be vaccinated, however, if not in the last 4 months of gestation but should be well fed, confined, and carefully observed between the 25th and 40th days postvaccination. One or two daily doses of standard (nonrepository) oxytetracycline hydrochloride should be injected at the first evidence of clinical illness. Cattle do not become fully immune until 6 weeks after vaccination. Although definitive evidence is lacking, the presumption is that vaccinated animals remain immune carriers for life. 6 Tetracyclines, chloramphenicol, or imidocarb should not be administered within 1 week before or 6 weeks following vaccination. Brucella abortus vaccine, anthrax vaccine, modified live P. hemolytica vaccines, and/or MLV BVD vaccines should probably not be administered within a similar time span. Vaccinated cattle permanently develop complement-fixing antibodies and will be ineligible for interstate movement to some states and export to some countries. However, if necessary, the carrier state can be abolished by treatment with tetracyclines,14 and the complement fixation titer will then disappear over a 6-month period. 6 Vaccinated cattle should not be treated for diseases such as pinkeye, footrot, or pneumonia with repository-type oxytetracycline products such as LA-200 (Pfizer, New York, NY 1001 7), as the carrier state may be abolished and the animals again become susceptible. I4 Anavac is the vaccine of choice in California for routine administration to 6- to 24-month-old cattle, in herds within endemic areas where tick transmission occurs. Vaccination is cost-effective only for bulls and heifers that will be retained in the breeding herd as adults. Ideally, calves should be vaccinated when they are between 7 and 12 months of age. Although outbreaks of anaplasmosis seldom occur in unvaccinated herds within such areas, a small proportion of adult cattle remain susceptible, and a 1 to 2% annual mortality rate from anaplasmosis can be expected. I5 The goal of a vaccination program in such areas is to prevent these sporadic losses. Anavac is also the vaccine of choice for administration to susceptible cattle of similar age that are about to be introduced into such an endemic area. Anavac would not ordinarily be the vaccine of choice (1) for use in
250
CHARLES
A.
HJERPE
the face of an outbreak of anaplasmosis (which will necessitate treatment with oxytetracycline) or (2) for use in susceptible cattle over 24 months of age that are to be introduced into endemic areas where tick transmission occurs. Within endemic areas where tick transmission does not occur, achieving and maintaining an anaplasmosis-free herd may be more cost-effective than vaccination. Carriers can be identified by serological testing and the carrier state abolished by treatment with tetracyclines. 2
REFERENCES 1. Ristic M: Anaplasmosis. In Amstutz HE (ed): Bovine Medicine and Surgery, ed 2. Santa Barbara, American Veterinary Publications, 1980, pp 324-348 2. Richey EJ: Bovine anaplasmosis. In Howard JL (ed): Current Veterinary TherapyFood Animal Practice 2. Philadelphia, WB Saunders, 1986, pp 622 - 626 3. Utterbach WW, Stewart LM, Beals TL, et al: Anaplasmosis survey in northern California, 1969 -1970: Prevalence of complement fixation antibodies in cattle by herd locations. Am J Vet Res 33:257 -267, 1972 4. Corrier DE, Guzman S: The effect of natural exposure to Anaplasma and Babesia infections in native calves in an endemic area of Columbia. Trop Anim HIth Prod, 9:47 -51, 1977 5. Blood DC, Radostits OM, Henderson JA, et al: Anaplasmosis. In Blood DC, Radostits OM (eds): Veterinary Medicine, ed 6. London, Bailliere Tindall, 1983, pp 875-878 6. Henry ET, Norman BB, Fly DE, et al: Effects and use of a modified live Anaplasma marginale vaccine in beef heifers in California. J Am Vet Med Assoc 183:66-69, 1983 7. Brock WE, Kliewer 10, Pearson CC: A vaccine for anaplasmosis. J Am Vet Med Assoc 147:948-951, 1965 8. Hawkins JA, Love IN, Hildalgo RJ: Mechanical transmission of anaplasmosis by tabanids. Am J Vet Res 43:732-734, 1982 9. Howell DE: Transmission of anaplasmosis by arthropods. Proc 3rd Natl Res Conf on Anaplasmosis in Cattle, Manhattan, KS, June 12-13, 1957, pp 14-16 10. Ryff JF, Breen H, Thomas GM: Control of anaplasmosis under Wyoming conditions. J Am Vet Med Assoc 145:43-46, 1964 11. Dennis RA, O'Hara pJ, Young MF, et al: Neonatal immunohemolytic anemia and icterus of calves. J Am Vet Med Assoc 156:1861-1869, 1970 12. Searl RC: Anaplasmosis control and treatment. Bov Pract 17:122, 1982 13. Bedell DM, Slater M: The use of a combination of the therapeutic and immunological regimens in an anaplasmosis epizootic. Biochem Rev 33:15-18, 1971 14. Magonigle RA, Newby TJ: Elimination of naturally acquired chronic Anaplasma marginale infection with a long-acting oxytetracycline. Am J Vet Res 43:21702172,1982 15. Goodger WJ, Carpenter T, Riemann H: Estimation of economic loss associated with, anaplasmosis in California beef cattle. J Am Vet Med Assoc 174:1333-1336, 1979
Anthrax Bacillus anthracis Vaccine Bacillus anthracis causes septicemia, dysentery, abortions, and acute to peracute deaths, with exudation of tarry blood, that fails to clot, from body orifices of the carcass. Anthrax is endemic on specific farms and ranches, where the sporulated organisms can persist in the soil for at least 60 years. l In addition, certain soils, especially poorly drained alkaline soils, 2 can maintain
247
immunity are important in protecting against salmonella and other facultative intracellular bacteria. 3 •4 The best hope for a satisfactory future vaccine, therefore, appears to be one that stimulates both humoral and cellular immunity in neonatal calves as well as in mature animals. Experimental, genetically-altered, modified-live salmonella vaccines elicit both humoral immunity and eMI in calves and protect against virulent challenge. 5 .
REFERENCES 1. Smith BP, Habasha FG, Reina-Guerra M, et al: Immunization of calves against salmonellosis. Am J Vet Res 41:1947-1951,1980 2. Spier S, Smith BP, Dilling G, et al: ELISA response to vaccination with a killed salmonella bacterin. Unpublished data; in preparation 3. Venneman MR, Berry LJ: Cell-mediated resistance induced with immunogenic preparations of Salmonella typhimurium. Infec Immun 4:381-382, 1971 4. Habasha FG, Smith BP, Schwartz L, et al: Correlation of macrophage migrationinhibition factor and protection from challenge exposure in calves vaccinated with Salmonella typhimurium. Am J Vet Res 46:1415-1421, 1985 5. Smith BP, Reina-Guerra M, Stocker BAD, et al: Aromatic-dependent Salmonella dublin as a parenteral modified-live vaccine for calves. Am J Vet Res 45:2231-2235, 1984
MISCELLANEOUS BOVINE RICKETTSIAL, BACTERIAL, AND VIRAL DISEASE VACCINES Anaplasmosis Vaccines Anaplasma marginale causes fever, anorexia, anemia, icterus, weakness, abortions, weight loss, emaciation, depressed testicular function in bulls, and sometimes death, especially in cattle over 2 years of age. Cattle under 12 months of age become infected but seldom manifest clinical signs of disease. In cattle over 36 months of age, disease is usually severe, and a case fatality rate of 30 to 50% is to be expected. Cattle between 12 and 36 months of age are variably affected. 1 ,2 General Considerations Within endemic areas, a high proportion of adult cattle may be immune carriers. 3 Calves born to immune dams are passively immune and resist infection until 1 to 6 months of age. 4 Within areas where anaplasmosis is endemic, the pattern of disease that is generally observed will be dependent upon (1) the prevalence of the carrier state and (2) the biological vectors that are present. Within areas where tick transmission occurs, most adult cattle are immune carriers, and clinical disease occurs only sporadically. 3 Most cattle within such areas become permanently infected when they are between 6 and 12 months of age and do not evidence clinical disease. 5 •6 The exception is when susceptible adults are introduced from nonendemic areas. In that event, high morbidity and mortality rates are to be expected. 5 Vaccination of such animals, at least 42 days prior to grazing endemic areas, is imperative. 7 Within endemic areas where tick transmission does not occur, most
248
CHARLES
A.
HJERPE
adult animals will be susceptible. Severe seasonal disease outbreaks may occur in association with increases in the populations of biting insects. 2•5 A minimum of 10 tabanid fly bites are required to accomplish mechanical transmission from an acutely affected bovine to a susceptible one. 8 Tabanid flies do not remain infective for more than 2 hours after feeding on an infected animal. 8 It has been shown that mechanical disease transmission by biting insects can be prevented if carrier cattle are not grazed within 1 to 2 miles of susceptible cattle. 9 •10 Anaplaz (Fort Dodge Laboratories, Fort Dodge, IA 50501). Anaplaz (R) is an inactivated vaccine. General recommendations for its use are summarized (see Table 9). Anaplaz is recommended for subcutaneous administration in two doses, not less than 4 weeks apart. Protection is achieved by 2 weeks following administration of the immunizing dose. 7 A single booster dose may be administered 12 months following the immunizing dose. Vaccinated cattle are immune for 12 months after primary vaccination and for 24 additional months after booster vaccination. 2 Vaccination prevents clinical disease but does not prevent infection. 2 Within endemic areas where tick transmission occurs, most (but not necessarily all) vaccinated cattle become immune carriers prior to expiration of vaccinal immunity. Anaplaz contains red cell antigens that can stimulate antierythrocyte antibody production in cows that are negative for the respective red cell antigens present in the vaccine. These antibodies are concentrated in the colostrum of parturient cows and heifers and may cause neonatal isoerythrolysis if ingested in sufficient quantities by newborn calves that have the same RBC type as is present in the vaccine. 11 This problem is minimized by (1) administering Anaplaz to heifers and cows at a time when they are not pregnant (so that by the time they are calving, their antierythrocyte antibody titers will have declined to low levels) and (2) by administering only a single-booster dose of vaccine to any particular cow during her lifetime. 12 Repeated boostering (at any time, but especially in late pregnancy) increases the risk of neonatal isoerythrolysis. 12 Bulls can be safely maintained immune for life by repeated boostering at 12- to 24-month intervals. 2 •12 The vaccine label insert warns that complement-fixing antibodies develop and persist for up to 4 months following administration of the second (immunizing) dose. This must be kept in mind when deciding on a program for control of anaplasmosis in cattle that are destined for interstate shipment or export. Anaplaz is the vaccine of choice for (1) administration to cattle over 24-months of age and (2) for use in the face of an outbreak. In the latter situation, Anaplaz is administered twice, with a 4-week interval, each time in combination with an injection of standard oxytetracycline hydrochloride, in a dose of 6.6 mg per kg of body weight. Parenteral administration of oxytetracycline in this dosage to an animal that is incubating the disease will delay the onset of clinical signs by approximately 28 days each time that it is done. This provides the 6 weeks of disease-free time that is required to achieve vaccinal immunity in exposed cattle. 13 However, because of the risk of neonatal isoerythrolysis,
BOVINE VACCINES AND HERD VACCINATION PROGRAMS
249
it may be best to segregate cattle that are pregnant 5 months or more, control their disease with chemotherapy, and postpone vaccination until after they have calved. 12 Anavac (BioLOGIC Laboratories, Davis, CA 95616) Anavac is a modified-live vaccine and is licensed for use only in California. 6 It utilizes a strain of A. marginale that has been modified by passage in sheep. General recommendations for its use are summarized (see Table 9). The vaccine must be stored in liquid nitrogen or on dry ice. It is recommended by the manufacturer for intramuscular administration in a single dose to healthy cattle between 1 month and 2 years of age. If carrier cows are known to be present in the herd, administration should be delayed until after 6 months of age, in order to ensure that passive antibodies do not interfere with active immunity. 4 If the vaccine is administered to cattle over 2 years of age, anemia, severe clinical disease, and death may occur, especially in bulls and heavily lactating cows. These cows may be vaccinated, however, if not in the last 4 months of gestation but should be well fed, confined, and carefully observed between the 25th and 40th days postvaccination. One or two daily doses of standard (nonrepository) oxytetracycline hydrochloride should be injected at the first evidence of clinical illness. Cattle do not become fully immune until 6 weeks after vaccination. Although definitive evidence is lacking, the presumption is that vaccinated animals remain immune carriers for life. 6 Tetracyclines, chloramphenicol, or imidocarb should not be administered within 1 week before or 6 weeks following vaccination. Brucella abortus vaccine, anthrax vaccine, modified live P. hemolytica vaccines, and/or MLV BVD vaccines should probably not be administered within a similar time span. Vaccinated cattle permanently develop complement-fixing antibodies and will be ineligible for interstate movement to some states and export to some countries. However, if necessary, the carrier state can be abolished by treatment with tetracyclines,14 and the complement fixation titer will then disappear over a 6-month period. 6 Vaccinated cattle should not be treated for diseases such as pinkeye, footrot, or pneumonia with repository-type oxytetracycline products such as LA-200 (Pfizer, New York, NY 1001 7), as the carrier state may be abolished and the animals again become susceptible. I4 Anavac is the vaccine of choice in California for routine administration to 6- to 24-month-old cattle, in herds within endemic areas where tick transmission occurs. Vaccination is cost-effective only for bulls and heifers that will be retained in the breeding herd as adults. Ideally, calves should be vaccinated when they are between 7 and 12 months of age. Although outbreaks of anaplasmosis seldom occur in unvaccinated herds within such areas, a small proportion of adult cattle remain susceptible, and a 1 to 2% annual mortality rate from anaplasmosis can be expected. I5 The goal of a vaccination program in such areas is to prevent these sporadic losses. Anavac is also the vaccine of choice for administration to susceptible cattle of similar age that are about to be introduced into such an endemic area. Anavac would not ordinarily be the vaccine of choice (1) for use in
250
CHARLES
A.
HJERPE
the face of an outbreak of anaplasmosis (which will necessitate treatment with oxytetracycline) or (2) for use in susceptible cattle over 24 months of age that are to be introduced into endemic areas where tick transmission occurs. Within endemic areas where tick transmission does not occur, achieving and maintaining an anaplasmosis-free herd may be more cost-effective than vaccination. Carriers can be identified by serological testing and the carrier state abolished by treatment with tetracyclines. 2
REFERENCES 1. Ristic M: Anaplasmosis. In Amstutz HE (ed): Bovine Medicine and Surgery, ed 2. Santa Barbara, American Veterinary Publications, 1980, pp 324-348 2. Richey EJ: Bovine anaplasmosis. In Howard JL (ed): Current Veterinary TherapyFood Animal Practice 2. Philadelphia, WB Saunders, 1986, pp 622 - 626 3. Utterbach WW, Stewart LM, Beals TL, et al: Anaplasmosis survey in northern California, 1969 -1970: Prevalence of complement fixation antibodies in cattle by herd locations. Am J Vet Res 33:257 -267, 1972 4. Corrier DE, Guzman S: The effect of natural exposure to Anaplasma and Babesia infections in native calves in an endemic area of Columbia. Trop Anim HIth Prod, 9:47 -51, 1977 5. Blood DC, Radostits OM, Henderson JA, et al: Anaplasmosis. In Blood DC, Radostits OM (eds): Veterinary Medicine, ed 6. London, Bailliere Tindall, 1983, pp 875-878 6. Henry ET, Norman BB, Fly DE, et al: Effects and use of a modified live Anaplasma marginale vaccine in beef heifers in California. J Am Vet Med Assoc 183:66-69, 1983 7. Brock WE, Kliewer 10, Pearson CC: A vaccine for anaplasmosis. J Am Vet Med Assoc 147:948-951, 1965 8. Hawkins JA, Love IN, Hildalgo RJ: Mechanical transmission of anaplasmosis by tabanids. Am J Vet Res 43:732-734, 1982 9. Howell DE: Transmission of anaplasmosis by arthropods. Proc 3rd Natl Res Conf on Anaplasmosis in Cattle, Manhattan, KS, June 12-13, 1957, pp 14-16 10. Ryff JF, Breen H, Thomas GM: Control of anaplasmosis under Wyoming conditions. J Am Vet Med Assoc 145:43-46, 1964 11. Dennis RA, O'Hara pJ, Young MF, et al: Neonatal immunohemolytic anemia and icterus of calves. J Am Vet Med Assoc 156:1861-1869, 1970 12. Searl RC: Anaplasmosis control and treatment. Bov Pract 17:122, 1982 13. Bedell DM, Slater M: The use of a combination of the therapeutic and immunological regimens in an anaplasmosis epizootic. Biochem Rev 33:15-18, 1971 14. Magonigle RA, Newby TJ: Elimination of naturally acquired chronic Anaplasma marginale infection with a long-acting oxytetracycline. Am J Vet Res 43:21702172,1982 15. Goodger WJ, Carpenter T, Riemann H: Estimation of economic loss associated with, anaplasmosis in California beef cattle. J Am Vet Med Assoc 174:1333-1336, 1979
Anthrax Bacillus anthracis Vaccine Bacillus anthracis causes septicemia, dysentery, abortions, and acute to peracute deaths, with exudation of tarry blood, that fails to clot, from body orifices of the carcass. Anthrax is endemic on specific farms and ranches, where the sporulated organisms can persist in the soil for at least 60 years. l In addition, certain soils, especially poorly drained alkaline soils, 2 can maintain