Trunk Wash of Elephants  (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords  
Description Routine diagnostic trunk washes for tuberculosis should include three trunk washes collected on three days over a one week period. The trunk washes should be collected in the morning, before the elephant is offered water. This protocol aims to obtain a representative sample of nasal flora which has collected in the trunk overnight and to avoid dilution of the collected sample with drinking water (since elephants use their trunks to suck up water for drinking). (P5.39.w4, D303.App3.w14)

Trunk wash in the standing elephant

Note: This protocol for trunk wash in the standing elephant requires that the elephant allow handlers to manipulate and restrain the trunk tip. This is generally resented by elephants. Elephants should be trained to present the trunk, allow it to be gently restrained manually and allow trunk tip manipulation. This may require two to four weeks of training in the average elephant, however the period will vary depending on the elephant, its prior training and the handlers' skills. (D303.App3.w14)

  • Have the elephant manually restrained by its handlers, with the trunk tip held up.
  • Fill a 60 mL sterile syringe with sterile saline, insert the syringe into one nostril and quickly flush the saline into the trunk.
  • Have the handler lift the trunk tip as high as possible (so the saline flows as far into the trunk as possible).
  • Place the one gallon plastic bag over the tip of the trunk.
  • Have the trunk lowered so that fluid drains out of it into the bag.
    • A good sample retrieves about 40 ml of the instilled saline.
    • Mucus from inside the trunk should be visible in the retrieved sample
    • There may be dirt and food particles in the sample; if these are excessive, consider repeating the sample collection.
  • If possible, also allow the elephant to exhale into the bag during the process of collection.
  • Transfer the collected material into a labelled container.
  • Refrigerate the sample and send directly to an appropriate laboratory for processing and mycobacterial culture.
    • Laboratory details for samples in the USA are provided in D303.App4.w15 - full text provided.
  • If immediate transport to the laboratory is not possible, freeze the sample at -20 to -10 C (i.e. in a standard domestic-type freezer) until it is sent to the laboratory.
    • Commonly, the three samples taken over a week are frozen until all the samples have been taken, then sent to the laboratory as a batch.

(P5.39.w4, D303.5.w5, D303.App3.w14 - full text provided)

Trunk wash in the recumbent anaesthetised elephant

Note: This may be suitable for elephants prior to importation. (P .2004.w, [Or for collection of samples from elephants which for any other reason cannot be handled in a manner suitable for collection by the standard technique described above.]

  • Wait until the elephant is stable under anaesthesia in left lateral recumbency.
  • Insert a 3 m long prepackaged sterile foal stomach tube into the nostril on the dependent side of the trunk.
  • Feed the tube up the trunk about 2.5 m.
  • Attach a 50 mL sample suction trap to the external end of the tube.
  • Attach the suction trap to a battery powered portable aspirator pump.
  • Activate the pump to collect the secretions from the proximal trunk.
  • If little or no secretions are collected, detach the sample trap from the tube, raise the free end of the tube and instill 100 mL sterile saline into the tube.
  • Reattach the sample trap and pump and collect a sample.
  • Replace the sample trap with a new sterile sample trap.
  • Withdraw the foal stomach tube from the nostril, insert it into the oral pharynx.
  • Collect an oesophageal sample into the second sample trap.


Appropriate Use (?)
  • To collect material to aid in the diagnosis of tuberculosis in elephants. Note: due to the limitations set out below, whilst a positive mycobacterial culture from trunk wash collections is strong evidence that the elephant is shedding mycobacteria, and thus presumably is infected, negative culture cannot be taken to indicate that the elephant is not infected. (P5.39.w4)
  • To monitor the success of treatment when TB-positive elephants are treated for the infection. Such monitoring requires repeated trunk washes both during the period of treatment and subsequent to it. (P5.39.w4)
  • Care must be taken to ensure that personnel working nearby are aware that a hands-on procedure is being carried out. Both personnel directly involved with the procedure, and those working nearby, need to ensure that movements and noise (from telephones, bleepers, shutting doors, heavy machinery etc.) that might disturb the elephant, both inside and outside the elephant area, are minimized during the procedure. This includes activities at nearby enclosures that might be audible to the elephant and could startle it. (V.w6, V.w72, V.w84, V.w86, V.w88)
  • Use of a rigid plastic container rather than a plastic bag, and whether a tube is inserted into the trunk or simply the end of the syringe is inserted, are matters for personal preference of those carrying out the procedure. (P5.39.w4)
  • Three samples should be collected on different days. (D303.5.w5, J54.19.w4) preferably over a period of a week. (D303.5.w5)
Complications/ Limitations / Risk
  • Elephants are very large, heavy and strong, highly intelligent, can move surprisingly quickly and can be highly strung at times: 
    • Depending on the management system (free contact / no contact / protected contact), and the character and training of the individual elephant, it may be necessary to carry out any hands-on procedure with the elephant under sedation and/or in an elephant restraint device.
    • There is always some risk to personnel involved when carrying out hands-on procedures on a conscious elephant.
    • There is always some risk to the elephant when sedation is used, especially if full anesthesia is required.

    (V.w6, V.w72, V.w84, V.w86, V.w88)

  • This procedure may be physically very dangerous for the handlers, particularly with an uncooperative elephant. (P5.39.w4)
    • Risk to the handlers can be greatly decreased, and efficiency of collection increased, by training the elephant to accept the procedure. (P5.39.w4)
    • For some elephants, having the elephant lie in sternal or lateral recumbency may increase handler safety, however this does NOT guarantee either safety or sample collection and extensive training is still required prior to the collection procedure. (P5.39.w4)
  • This procedure involves potential exposure of humans to aerosolised mucus from the elephant's respiratory tract and thus presents a potential zoonotic risk. (P5.39.w4)
    • It is suggested that all personnel involved in the collection procedure should wear appropriate personal protective equipment such as a well-fitting respirator or face mask which can filter particles of 0.3 microns diameter, and disposable gloves. The procedure should take place in a well-ventilated sunlit area. (P5.39.w4)
  • There are limitations to the efficacy of mycobacterial culture of trunk wash material as a primary method for detection of tuberculosis in elephants. It relies on the following assumptions: (P5.39.w4)
    • Most elephants with mycobacterial infection will have a respiratory system infection;
    • Most infected animals shed mycobacterial organisms into the respiratory tract;
    • Infected, shedding, elephants will pass mycobacterial organisms into the trunk at least once over the three-day period of sample collection.
    • Contaminants will not generally overgrow or mask growth of pathogenic mycobacteria.


  • This procedure will only detect elephants which are shedding mycobacterial organisms through the trunk, not necessarily all infected individuals. (P5.39.w4)
  • Latently infected individuals or those shedding organisms only intermittently will be difficult to detect with this procedure. (P5.39.w4)
  • Detection from trunk wash culture has poor sensitivity. (J219.13.w1)
Equipment / Chemicals required and Suppliers

For collection in the standing elephant

  • Sterile 0.9% saline solution.

  • Sterile 60 ml syringe.

  • Heavy duty one gallon capacity plastic zip lock type bags OR a sterile plastic container, if preferred.

  • Sterile 14 gauge rubber feeding tube if preferred for flushing the saline into the trunk.

  • Sterile 50 mL screw-top plastic jar/centrifuge tube.

For collection in the recumbent anaesthetised elephant:

  • 3 m long prepackaged sterile foal stomach tube

  • Sterile 0.9% saline

  • Suction traps

  • Battery powered portable aspirator pump

Expertise level / Ease of Use
  • Expertise and experience of the elephant handler(s) are critical when carrying out hands-on procedures on a conscious elephant. (V.w6, V.w72, V.w84, V.w86, V.w88)
  • Not technically difficult in a veterinary sense, requiring only basic maintenance of sterility.
  • Requires considerable expertise in elephant handling to maximise efficiency and minimise risk of injury to personnel.
  • To obtain adequate samples, the elephant and its caretaker must be trained. (J219.13.w1)
Cost/ Availability
  • Requires access to an appropriate laboratory for mycobacteriological culture.
Legal and Ethical Considerations
  • When working with elephants it is important always to remember that their size and weight means that they can injure people easily, whether intentionally or unintentionally. The potential risks to all personnel involved must be considered before any hands-on procedure is initiated, and remembered during the procedure. It is critical that all personnel are highly trained and understand their respective roles and responsibilities during the procedure, that one person has overall command responsibility, and that no unnecessary people are present within the contact area. (V.w6, V.w72, V.w84, V.w86, V.w88)
  • This procedure involves potential exposure of humans to aerosolised mucus from the elephant's respiratory tract and thus presents a potential zoonotic risk. (P5.39.w4)
  • Detection of a TB-shedding elephant requires decisions regarding the future of that elephant, and its management: management may require that the infected animal and its herd be isolated, that the infected animal be removed from exhibition/shows, treatment of the infected animal/exposed herd (which can be very expensive) and possibly euthanasia of the animal. (P5.39.w4)
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Susan K. Mikota DVM (V.w72)
References D303.5.w5, D303.App3.w14, D303.App4.w15 [Note: full text of D303 - Guidelines for the control of tuberculosis in elephants 2003 is provided in Wildpro], J54.19.w4, J219.13.w1, P5.39.w4, P9.2004.w1, V.w6, V.w72, V.w84, V.w86, V.w88

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