Vaccination

Written by Willem Schaftenaar

Introduction

Based on historical data on infectious diseases which may have severe clinical impact on elephants kept under human care, vaccination against some of these diseases is recommended. The choice for a certain vaccine depends on the environmental pathogen pressure, the way the elephant is kept (zoo – semi free ranging) and the location/climate. Unfortunately there is not much scientific evidence of the efficacy for some of the vaccines available, as true vaccination challenge trials are not possible in the case of elephants. Data on vaccine induced antibody titers are scarce (Muir, 2021; Lindsay, 2010). In a study about maternal antibody transmission and the lifespan of antibodies, it was found that maternal antibody levels in the elephant calf were as high as in the dam after vaccination of the pregnant dam against tetanus and rabies. These antibodies remained elevated for 144 days (Noffs, 2013). Similar results were found for EEHV-antibodies in naturally infected elephants in which case the antibodies remained elevated until 36 months (Fuery, 2020).

 

Vaccination has been practiced against the following diseases:

 

  1. Tetanus

  2. Anthrax

  3. Cowpox

  4. Clostridium spp.

  5. Rabies

  6. Pasteurellosis (Hemorrhagic septicemia)

  7. Foot-and-mouth disease

 

References

  • Fuery, A, Pursell,T., Tan, J, Peng, R, Burbelo, P.D., Hayward, G.S., Ling, P.D.2020. Lethal Hemorrhagic Disease and Clinical Illness Associatedcwith Elephant Endotheliotropic Herpesvirus 1 Are Caused by Primary Infection: Implications for the Detection of Diagnostic Proteins. J. Vir. Volume 94 Issue 3.

  • Lindsay, W. A., Wiedner, E., Isaza, R., Townsend, H. G., Boleslawski, M., Lunn, D. P. 2010. Immune responses of Asian elephants (Elephas maximus) to commercial tetanus toxoid vaccine. Vet Immunol Immunopathol 133 (2-4), 287-289.

  • Muir, Y.S.S., Bryant, B., Campbell-Ward, M., Higgins, D.P., 2021. Retrospective anti-tetanus antibody responses of zoo-based Asian elephants (Elephas maximus) and rhinoceros (Rhinocerotidae). Developmental & Comparative Immunology 114, 103841. doi:10.1016/j.dci.2020.103841

  • Nofs S.A., Atmar R.L., Keitel W.A., Hanlon C., Stanton J.J., TanJ., Flanagan J.P., Howard L., Ling P.D., 2013. Prenatal passive transfer of maternal immunity in Asian elephants (Elephas maximus). 2013. Veterinary Immunology and Immunopathology, Volume 153, Issues 3–4, 2013, Pages 308-311.

1. Tetanus (Clostridium tetani)

Only a few cases of clinical tetanus in elephants have been described in the literature (Goss 1947, Burke 1975, Fowler et al 2006) or have been reported anecdotally for Asian elephants in Southeast Asia.

In a preliminary study, measurable titers against tetanus were achieved in Asian elephants vaccinated with a 1 ml dose of monovalent equine tetanus toxoid followed by a booster at 4 weeks. The titers remained elevated for >1 year; however, the appropriate vaccination interval has not yet been determined. Annual vaccination is commonly practiced, although it is likely that the duration of immunity may be longer. In a study in which 9 Asian elephants were involved, Muir et al (2021) demonstrated that the antibody titers in these elephants remained at adequate levels with little fluctuations when 3-5 years intervals were applied. Elephants kept in European zoos are recommended to adhere to the suggested vaccination regime for horses with booster vaccinations every 2-3 years.

Government owned elephants in Myanmar are routinely vaccinated against tetanus using an equine tetanus toxoid vaccine (5 ml, s.c.);  (pers. comm. Khyne U Mar, 2018). The initial course consists of two injections given approximately four to six weeks apart followed by a booster at one year and further boosters annually.

 

References tetanus

  • Goss, L.J. 1942. Tetanus in an elephant. Elephas maximus. Zoologica NY 27:5–6.

  • Burke, T.J. 1975. Probable tetanus in an Asian elephant. JZ&WM, vol 6 – 1 22-24

  • Mikota, S.K. 2006. Preventive Health Care and Physical Examination. In: Fowler, M.E. and Mikota, S.K.(eds). Biology, Medicine, and Surgery of the Elephant. Blackwell Publishing, Ames, IA. Pp. 67-73.

  • Lindsay, W. A., Wiedner, E., Isaza, R., Townsend, H. G., Boleslawski, M., Lunn, D. P. 2010. Immune responses of Asian elephants (Elephas maximus) to commercial tetanus toxoid vaccine. Vet Immunol Immunopathol 133 (2-4), 287-289

  • Transmissible Diseases Handbook. 2019. Infectious diseases Fact sheet TETANUS.

  • Muir, Y.S.S., Bryant, B., Campbell-Ward, M., Higgins, D.P., 2021. Retrospective anti-tetanus antibody responses of zoo-based Asian elephants (Elephas maximus) and rhinoceros (Rhinocerotidae). Developmental & Comparative Immunology 114, 103841. doi:10.1016/j.dci.2020.103841

2. Anthrax (Bacillus anthracis)

Outbreaks of Anthrax in livestock are a threat to wildlife, including elephants (Walsh, 2019). Anthrax affects African and Asian elephants, free ranging as well as elephants kept under human care (Lindeque,1994; Yasothai, 2013). The disease can be fatal, however antibodies have been detected in healthy elephants as well (Cizauskas, 2014). Annual vaccination of livestock is the only way to protect wild elephants against this disease. Elephants kept under human care, however, can be vaccinated annually with a commercially available vaccine. This is highly recommended in areas where anthrax is seen in farm animals or if there is a history of anthrax in elephants in that area. An attenuated vaccine (Sterne strain 34F2, https://www.cdc.gov/anthrax/resources/anthrax-sterne-strain.html) developed for farm animals, has been widely used in government kept elephants in Myanmar under the following recommendations: annual vaccination (1 ml s.c.) in April of elephants older than 6 months, with the exception of sick elephants and pregnant elephants if the fetus is under 8 months (pers. comm. Khyne U Mar, 2018).

 

References Anthrax

  • Lindeque, P.M.; Turnbull, P.C.B.; Verwoerd, Daniel Wynand. 1994. Ecology and epidemiology of anthrax in the Etosha National Park, Namibia. http://hdl.handle.net/2263/33072

  • Cizauskas,C.A., S.E. Wendy C. TurnerVance, R.E., and Getz, W.M. 2014. Frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system. In: Animal Ecology, 83 ( 5), 1078-1090

  • Walsh M.G., Mor S.M., and Hossain S. 2019. The elephant – livestock interface modulates anthrax suitability in India. Proc. R. Soc. B 286: 20190179. http://dx.doi.org/10.1098/rspb.2019.0179.

  • Yasothai R. 2013. A report on outbreak of anthrax in elephant. International Journal of Science, Environment and Technology, Vol. 2, No 4, 2013, 757 – 759.

3. Cowpox

Cowpox (= Orthopox) virus infections have been reported in both Asian and African elephants. Most cases have occurred in Western Europe. Symptoms may vary from minor lesions to fatal infection. Severe cases have been reported more frequently in Asian elephants than in African elephants, but both species are susceptible.

The European Association of Zoo and Wildlife Veterinarians (EAZWV)has produced a fact sheet about cowpox infections in zoo animals, including several references to cowpox infections in elephants (Transmissible Diseases Handbook 2019).

Prevention: preventive vaccination of African and Asian elephants is strongly recommended by the EAZWV and encouraged in the coordinated European Association of Zoos and Aquaria (EAZA) EAZA breeding programs of both species. The only vaccine available is a Modified Vaccinia Ankara (MVA) vaccine, which is specially produced on request and distributed by the Institut für Infektionsmedizin und Zoonosen, Dr. Robert Fux (Robert.fux@lmu.de), Veterinärstrasse 13, 80539 München, Germany. MVA has been used for many years in elephants, rhinos and tapirs without any side effects. Primo-vaccination of keepers or other staff members in contact with vaccinated animals is not required.

 

Cowpox vaccination schedule:

First vaccination (s.c. or i.m.) of 4 ml MVA at the age of 12-16 weeks.

Second vaccination (s.c. or i.m.) of 4 ml MVA 4 weeks after the first injection. The producer of the vaccine advices and offers antibody titer measurement before the vaccination and 3-4 weeks after the second vaccination. In young and untrained elephants this may not be possible, and vaccination should be practiced without titer monitoring.

Booster vaccinations: generally once every 2-3 years, depending on the antibody titer.

 

Vaccination during pregnancy: following this vaccination advice, elephants should be immune before they become pregnant. There are no sound studies about the possible side effects of vaccination on the fetus. New non-vaccinated imports or elephants with unknown vaccination status should not be bred before they are properly vaccinated.

 

Remarks: for ordering and using this noncommercial vaccine, a special permit from your official veterinarian is required. Please contact your official veterinarian for further instructions regarding the import of MVA from Germany.

Some countries may impose restrictions regarding the contact between humans (staff, visitors) and elephants for the first two weeks after vaccination. However, there is no recommendation for this measure and it is not supported by scientific evidence or by the producer. As MVA only replicates once in mammalian tissues, it is safe and developed for use in humans.

References cowpox:

 

  • Chantrey J, Meyer H, Baxby D, Begon M, Bown KJ, Hazel SM, Jones T, Montgomery WI, Bennett M. 1999. Cowpox: reservoir hosts and geographic range. Epidemiol Infect. 122: 455-460.

  • Eulenberger K, Bernhard A, Nieper H, Hoffman K, Scheller R, Meyer H, Zimmerman P, Essbauer S, Pfeffer M, Kiessling J. 2005. An outbreak of cowpox infection in black rhino (Diceros bicornis) at Leipzig Zoo. Verh ber Erkrg Zootiere. 42:77-85

  • Kurth A, Nitsche A. 2011. Cowpox in Zoo Animals. In: Miller ER, Fowler ME (eds) Fowler's zoo and wild animal medicine current therapy, Volume 7. Elsevier, St. Louis, Missourri. pp: 32-37.

  • Kurth A, Wibbelt G, Gerber HP, Petschaelis A, Pauli G, Nitsche A. 2008. Rat-to-elephant-to-human transmission of cowpox virus. Emerg Infect Dis. 14: 670-671.

  • Pilaski J, Jacoby F. 1993. Die Kuhpocken-Erkrankungen der Zootiere. Verh ber Erkrg Zootiere. 35: 39-50.

  • Pilaski J, Rosen-Wölff R. 1987. Poxvirus infection in zoo-kept mammals. In: Darai G (ed) Virus diseases in laboratory and captive animals. Martinus Nijhoff Publishing, Boston. pp: 83-100.

  • Pilaski J, Schaller K, Matern B, Klöppel G, Mayer H. 1982. Outbreaks of pox among elephants and rhinoceroses. Verh ber Erkrg Zootiere. 24: 257-265.

  • Pilaski J, Kulka D, Neuschulz N. 1992. outbreak of pox disease in African elephants (Loxodonta africana) at the Thuringer Zoopark Erfurt. Verh ber Erkrg Zootiere. 34: 111-118.

  • Transmissible Diseases Handbook. 2019. Infectious diseases fact sheet: Cowpox virus

  • Wisser J, Pilaski J, Strauss G, Meyer H, Burck G, Truyen U, Rudolph M, Frölich K. 2001. Cowpox virus infection causing stillbirth in an Asian elephant (Elephas maximus). Vet Rec. 149: 244-246.

4. Clostridium spp.

Several zoos have vaccinated their elephants against multiple-strain Clostridium spp, with Clostridium perfringens being the major target. Not much is known about the impact of these potential pathogens on the health of elephants. Boonsri et al. describe 2 fatal cases in which C. perfringens was involved (Boonsri, 2018). Both cases were associated with EEHV-infection. A study performed in healthy elephants kept in zoos demonstrated the presence of Clostridium spp. in 3.5% of the Asian elephants (n=85) and no prevalence in African elephants (n=50) (Scharling, 2021). Preliminary data from necropsy reports revealed 13 cases of Clostridium spp involved in the death of Asian elephants (n=226), excluding 5 botulism victims. Of these cases, 5 were attributed to C. perfringens, 1 to C. septicum and 7 were unclassified Clostridium spp. In the same preliminary report, 1 case of C. perfringens involvement was found at necropsy of 112 African elephants (Bacciarini, 2001, Hess A, personal communication 2021). Two cases were identified as C. difficile (Bojesen A.M. 2006).  However, it is not clear from most of the necropsy reports whether Clostridium spp. were involved in the primary disease process or just an additional finding. For a long time it was assumed that Clostridium was a fatal pathogen in young elephant, but possibly EEHV-HD cases have been wrongly identified as Clostridium cases. Now that we look more closely at necropsies, the involvement of Clostridium as primary pathogen has become more questionable.

Quite severe skin lesions have been anecdotally reported after the use of oil-based vaccines containing multiple Clostridium spp. If the veterinarian decides to use a multiple-strain Clostridium-vaccine, water-based formulations should be used.

 

References Clostridium spp.:

 

  • Boonsri K., Somgird C., Noinafai P., Pringproa K., Janyamethakul T., T., Brown J.L., Tankaew P, Srivorakul S., Thitaram C. 2018. Elephant endotheliotropic herpesvirus associated with Clostridium perfringens infection in two Asian elephant (Elephas maximus) calves. Journal of Zoo and Wildlife Medicine 49(1), 178-182.

  • Scharling F.S., Bertelsen M.F., Sós E., Bojesen A.M., 2020. Prevalence of Salmonella species, Clostridium perfringens, and Clostridium difficile in the feces of healthy elephants (Loxodonta species and Elephas maximus) in Europe. Journal of Zoo and Wildlife Medicine 51(4), 752-760.

  • Bacciarini, L. N., Grone, A., Pagan, O., & Frey, J. 2001. Clostridium perfringens  2-toxin in an African elephant (Loxodonta africana) with ulcerative enteritis. Veterinary Record, 149(20), 618–620. doi:10.1136/vr.149.20.618.

  • Bojesen A.M., OlsenK.E.P., Bertelsen M.F. 2006. Fatal enterocolitis in Asian elephants (Elephas maximus) caused by Clostridium difficile. Veterinary Microbiology, 116 (4), 329-335

5. Rabies

Rabies in elephants has been reported sporadically (Wimnalratne, 1999; Aravind, 2006). Newspapers have reported on outbreaks of rabies in elephants. In areas with a high incidence of rabies in other species, vaccination of elephants kept under human care should be considered. In one study in African elephants, 2 ml of a commercuial available inactivated rabies vaccine was used (i.m.) to evaluate the serum antibodies (Miller, 2009). No other recommendations about the vaccine and dosages are given in the literature. Following the recommendation for rabies vaccination in horses is probably prudent. These inactivated vaccines can probably best be given from the age of 6 months, to be repeated after 3-4 weeks and annually boostered.

 

References:

 

6. Pasteurellosis (Hemorrhagic septicemia, Pasteurella multocida)

Hemorrhagic septicemia, caused by Pasteurella multocida (more recently renamed as Mannheimia multocida) has been reported as a cause of death in elephants (Chandranaik, 2016). 43 out of 85 elephant sera tested positive on antibodies in a newly developed ELISA. As in other mammals, P. multocida is a pathogen that can present on a spectrum from inapparent to a fatal disease. In areas with a pressure of P. multocida in livestock, vaccination of elephants against hemorrhagic disease is recommended.

In Myanmar a commercial aluminium-precipitated (inactivated) vaccine has been used for many years  in government kept elephants. Elephants older than 6 months are vaccinated twice a year (June and December, 5 ml, s.c.) with the exception of sick elephants and pregnant elephants if the fetus is under 8 months (pers. comm. Khyne U Mar, 2018).

 

References:

  • Chandranaik, B. M., Shivashankar, B. P., Giridhar, P., & Nagaraju, D. N. (2016). Molecular characterisation and serotyping of Pasteurella multocida isolates from Asiatic elephants (Elephas maximus). European Journal of Wildlife Research, 62(6), 681–685.

  • Tankaew P, Singh-La , Titaram C, Punyapornwittaya V, Vongchan P, Sawada T, Sthitmatee N. 2017. Evaluation of an In-house indirect ELISA for detection of antibody against haemorrhagic septicemia in Asian elephants, Journal of Microbiological Methods, Volume 134, 2017, Pages 30-34.

  • https://www.tribuneindia.com/news/nation/elephant-deaths-in-odisha-caused-by-bacteria-central-investigation-team-216885

7. Foot-and-mouth disease (FMD).

Very few cases of FMD have been reported in elephants (Rout, 1988; Schaftenaar, 2001) and are always related to outbreaks in livestock. Asian elephants are far more susceptible than African elephants (Schaftenaar, 2001) with a high mortality rate in the Asian species. Outbreaks have been described in India. In most countries vaccination against FMD is strictly regulated by the government in order to conytrol FMD outbreaks in the livestock industry. Whenever elephants are at risk for FMD, government authorities should be contacted and a vaccination program for the animals at risk should be started. The type of vaccine to be used, depends highly on the availability in the country and the FMD-strain that caused the outbreak. Dosages used for cattle should be applied.

 

  • References:
    Schaftenaar W. 2001. The occurrence of Foot-and-mouth disease in zoological gardens: a review. Implications of legislation for the present situation in zoos. 2001. Special issue on the 40th international symposium on diseases of zoo- and wild animals. Annual meeting of the EAZWV.

  • Schaftenaar W. 2002. Use of vaccination against foot and mouth disease in zoo animals, endangered species and exceptionally valuable animals. Rev. sci. tech. Off. int. Epiz., 2002, 21 (3), 613-623

  • Rout M, Nair, N. S.Biswajit DasSaravanan Subramaniam,  Mohapatra, J. K.Bramhadev Pattnaik. Foot-and-mouth disease in elephants in Kerala state of India during 2013. Indian Journal of Animal Sciences 2016 Vol.86 No.6 pp.627-631.H.

  • RAHMAN, P. K. DU-ITA and J. N. DEWA. 1988. Foot and Mouth Disease in Elephant (Elephas maximus)  J. Vet. Med. B 35, 7C-71 (1988).

  • Transmissible Diseases Handbook. 2019. Infectious disease fact sheet: Foot-and-mouth disease.

*Sick elephants and pregnant elephants carrying a fetus is under 8 months should not be vaccinated

Overview of recommended vaccinations *