Rabies
Elephant Care International Fact Sheet

Susan Mikota DVM

Etiology

• a Lyssavirus in the family Rhabdoviridae
• Lyssaviruses may have evolved in Africa

Epizootiology

• worldwide distribution (except Australia, the UK, Scandinavia…
• all warm blooded mammals susceptible

Transmission and Pathogenesis

• incubation variable - 3 weeks to many months
• transmitted by bites from reservoir hosts
• reservoir hosts vary geographically
• natural host in U.S. spotted skunk Spirogale putorius
  • other aberrant / reservoir hosts
  • striped skunk, bats, , raccoon, gray and red fox, coyote,
• domestic dog in Asia, South America, Africa
• civets, mongoose in Africa

Clinical Signs in Elephants

• anorexia
• behavior changes
• incoordination, paralysis of trunk or limbs
• restlessness, aggression, blindness

Diagnosis

• antemortem: no definitive test available
• postmortem*:

• hisopathology: Negri bodies (intracytoplasmic inclusion bodies).

• immunofluorescent antibody test (IFA) of brain tissue – definitive; global standard

• mouse inoculation

Differential diagnosis

·        rabies should be in the DDx of any disease that presents with CNS signs

• EMCV
• tetanus
• toxicity  (e.g. heavy metal; pesticide)
• trauma

Management

• vaccination prudent in endemic areas
• killed vaccine only
  • Measurable titers (up to 1:1100 in RFFIT)^** against rabies have been achieved in African elephants vaccinated with a single 2 cc dose of killed rabies vaccine IM (IMRAB 3, Merial, Duluth, Georgia, USA, www.us.merial.com).
  • Titers persisted at >1:50 for at least 2 years. Based on this preliminary data a dosage regimen of 2 cc killed rabies vaccine IM every 2 years is recommended (Michele Miller DVM PhD, Elephant SSP)
• no treatment available
• isolate suspect cases; no contact

Zoonotic potential

• rabies is a zoonotic disease and is fatal for humans
• no reports of transmission from elephants to humans but possible

* use caution when examining tissues from rabies suspects

** The Rapid Fluorescent Focus Inhibition Test (RFFIT) is a laboratory test that detects 
rabies virus neutralizing antibodies. The threshold for a protective titer in animals has 
not been established, however, a titer greater than 1:5 is considered protective in humans. 
This is the test used at Kansas State University; it is not a species-specific assay.

Links for general information about rabies:

1. Merck Manual:

http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/102200.htm

2. AVMA: http://www.avma.org/pubhlth/rabies_compendium_2005.pdf

3. CDC: http://www.cdc.gov/ncidod/dvrd/rabies/

4. Medline: http://www.nlm.nih.gov/medlineplus/rabies.html

5. E-medicine: http://www.emedicine.com/emerg/topic493.htm

6. WHO:

http://www.who.int/GlobalAtlas/home.asp

http://www.who.int/mediacentre/factsheets/fs099/en/

7. Wikepedia (on-line encyclopedia): http://en.wikipedia.org/wiki/Rabies

Rabies References with Abstracts June 2005

Elephant Care International Bibliographic Database (www.elephantcare.org)

    1.   Chakraborty,A. 2003. Diseases of elephants (Elephas maximus) in India-A Review. Indian Wildlife Year Book 2:74-82.

   2.   Wimalaratne,O. and Kodikara,D.S. 1999. First reported case of elephant rabies in Sri Lanka. Veterinary Record 144(4):98.
Abstract: An 84-year-old female domesticated elephant presented with a 4-day history of lethargy. Appetite and water intake was normal but the following day she was unsteady, aggressive and restless. There were secretions from both temporal glands. On the sixth day she was completely anorectic, had developed paralysis of the trunk and was unable to stand, falling each time she tried to stand up, and she was noticed to be blind. She died on the ninth day after the first symptoms were observed. PM examination showed the brain to be more vascular than normal and a brain smear was positive for rabies antigen. A serum sample went to the WHO Collaborating Center for Rabies in Bangkok, Thailand, which determined a rabies virus neutralizing antibody titre of 0.68 IU/ml by the rapid fluorescent focus inhibition test. Antigenic typing and genetic sequencing showed the virus to be similar, but not identical, to the common Sri Lankan dog rabies variant, although there was no history of an animal bite to the elephant.

   3.   Chandrasekharan,K., Radhakrishnan,K., Cheeran,J.V., Nair,K.N.M., and Prabhakaran,T., 1995. Review of the Incidence, Etiology and Control of Common Diseases of Asian Elephants with Special Reference to Kerala. In Daniel,J.C. (Editor). A Week with Elephants; Proceedings of the International Seminar on Asian Elephants.Bombay, India Bombay Natural History Society; Oxford University Press, pp. 439-449.
Abstract: Incidence, etiology, symptoms and control of specific and non-specific diseases of captive and wild elephants have been reviewed. Asian elephants have been observed to be susceptible to various parasitic diseases such as helminthiasis, trypanosomiasis and ectoparasitic infestations, bacterial diseases such as tetanus, tuberculosis, haemorrhagic septicemia, salmonellosis and anthrax, viral diseases such as foot and mouth disease, pox and rabies and non-specific diseases like impaction of colon, foot rot and corneal opacity. A detailed study extending over two decades on captive and wild elephants in Kerala, revealed high incidence of helminthiasis (285), ectoparasitic infestation (235), impaction of colon (169) and foot rot (125). Diseases such as trypanosomiasis (21), tetanus (8), tuberculosis (5) pox (2) and anthrax (1) were also encountered. The line of treatment against the diseases mentioned, have been discussed in detail.

   4.   Berry,H.H. 1993. Surveillance and control of anthrax and rabies in wild herbivores and carnivores in Namibia. Revue Scientifique et Technique Office International des Epizooties 12(1):137-146.
Abstract: Anthrax has been studied intensively in Etosha National Park, Namibia since 1966; in addition, since 1975, mortality due to rabies and all other causes has been recorded, totaling 6190 deaths. Standard diagnostic procedures demonstrated that at least 811 deaths (13%) were due to anthrax and 115 deaths (2%) were caused by rabies. Of the total number of deaths due to anthrax, 97% occurred in zebra (Equus burchelli), elephant (Loxodonta africana), wildebeest (Connochaetes taurinus) and springbok (Antidorcas marsupialis) while 96% of rabies deaths occurred in kudu (Tragelaphus strepsiceros), jackal (Canis mesomelas), bat-eared fox (Otocyon megalotis) and lion (Panthera leo). Anthrax deaths were highest in the rainy season for zebra, wildebeest and springbok, while elephant mortality peaked during dry seasons. No statistical relationship existed between seasonal rainfall and overall incidence of either anthrax or rabies. Control of anthrax is limited to prophylactic inoculation when rare or endangered species are threatened. Incineration of anthrax carcasses and chemical disinfection of drinking water are not feasible at Etosha. Rabies control consists of the destruction of rabid animals and incineration of their carcasses when possible.

   5.   Arora,B.M., 1992. An overview of infectious diseases and neoplasms of the elephants (Elephas maximus) in India. In Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors). The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989).Trichur, India Kerala Agricultural University, pp. 159-161.

   6.   Gopal,T. and Rao,B.U. 1984. Rabies in an Indian wild elephant calf. Indian Veterinary Journal 61(1):82-83.

   7.   McGaughey,C.A. 1962. Diseases of elephants. Part 4. Ceylon Veterinary Journal 10:3-9.

   8.   Gupta,V. 1945. Rabies in an elephant. Indian Veterinary Journal May.

   9.   Beckett,J. 1932. Death of an elephant from rabies. Journal of the Bombay Natural History Society 36:242-243.

10.   Ramiah,B. 1932. Paralytic rabies in an elephant. Indian Veterinary Journal 9:142.

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