Unfortunately, the diseases of monitor lizards are many and the cures are few (Kohler 1992:
Stanfill 1995). The good news is that once an imported monitor is cleared of disease. it
should be possible to keep it that way by keeping its enclosure and furnishings clean and
avoiding any contact with sources of contamination such as wild foods and other reptiles
whose health is suspect or unknown. The bad news is that wild-caught monitor lizards
always harbour parasites that have the potential to destroy their host, especially when they
have been subjected to the stress of capture and shipment For this reason all new monitors
should be carefully quarantined until they are determined to be free from disease. This means
keeping them in a separate room in a regularly sterilised enclosure used solely for this
purpose. These organisms noed to be identified and destroyed by a qualified vet. The
presence of most serious parasites can be identified from samples of blood and faeces and are
treated with a variety of drugs. Obviously it would be very foolish to attempt to diagnose and
treat the diseases of tropical reptiles without professional help. More and more vets are
developing an interest in exotic wildlife and most herpetological societies or zoos will
recommend a specialist. Vets are very well trained and in the best position to diagnose
disease and prescribe cures but it may be necessary to haggle hard over their fees. The use of
do-it-yourself guides to the diagnosis and cure of reptile diseases cannot be recommended.
Until animals have been pronounced free from infection by the vet they should be isolated
from all other animals. Clinical standards of hygiene are required in the quarantine enclosure.
It should be well isolated from all other terrariums and only contain furnishings that can be
sterilised. In all other respects it should be designed in the same manner as other terrariums
and the lizards supplied with adequate space. light, heat, food, hiding places etc. Newly
imported monitor lizards are often particularly nervous and this stress further weakens their
ability to withstand disease. As far a possible the animals should be left undisturbed.
Careful quarantine and early elimination of potential pathogens by an expert is the key to
keeping monitor lizards healthy. Thereafter they should remain healthy providing that their
basic needs (good diet, correct temperatures and humidity, freedom from stress) are met and
they are not exposed to infection from other reptiles whose health is suspect. A study of
cause of death in 248 monitor lizards concluded that almost half had died as the result of
infections (Kohler 1988). Whenever a monitor lizards appears to be ill it should be isolated
immediately and the advice of an vet obtained without delay. To be on the safe side it is wise
to have even long term captives screened for parasites by a vet every year or so.
As well as internal parasites monitors are host to a many external parasites that attach
themselves to the lizards' skins and suck their juices. Some lizard ticks are very beautiful and
their ecology is fascinating (e.g. Hesse 1985, Auffenberg & Auffenberg 1990), but in
captivity they must be regarded solely as vectors of disease. They should be dabbed with
alcohol and removed with tweezers, taking care not to pull off the bodies and leave the
mouthparts embedded in the lizard. lf ticks spread to other lizards it may be necessary to
destroy them with insecticides, for which veterinary advice should be obtained.
Obviously it makes sense only to buy healthy animals in the first place. Obtaining young
captive bred animals is ideal, but at present wild caught specinnens are usually the only
available option for most species. As in all walks of life there are a number of disreputable
characters who are not adverse to selling animals which they know have no chance of
survival. Again, members of your local herpetological society will probably be happy to
pinpoint the rogue dealers and recommend those that are honest and conscientious.
Purchasing animals without seeing them fust is asking for trouble unless you are buying them
from a dealer whose reputation is unblemished. No matter how honest your supplier,
inevitably some species of monitor lizard are very heavily infested with parasites when they
arrive at their final destination. Most have the potential to survive for long periods in
captivity if they are still strong and receive immediate veterinary care, but most untreated
specimens are doomed within weeks, and Doctor Dolittle himself would be unable to save
When buying a monitor lizard it should be examined very carefully. Particular points to look
- The monitor should be lively rather than lethargic. It should be very interested in food, be
able to hold its body off the floor, walk normaliy and be observed to protrude its tongue.
Newly imported specimens should struggle vigourously when handled. Missing toes and tail
tips are not a serious problem except in highly arboreal species such as the New Guinea tree
- There should be no sores, lumps or bums on the body or tail. Look underneath, in the
folds of skin at the insertion of the limbs with the body and pay particular attention to the
shape of the spine. There should be no sign of swelling in any of the limbs.
- 0pen the mouth and look for signs of rot or parasites, refuse any whose breath smells
- The eyes should be clear and not bloodshot, the nostrils should be dry and free from any
- There should be a finn deposit of fat at the base of the tail. Absence of fat does not
necessarily indicate disease however. Specimens captured just after a period of inactivity or
females after oviposition often appear somewhat emaciated.
- Breathing should be unlaboured; Wheezing, coughing and sneezing are early signs of
An animal offered for sale which shows any untoward symptoms should be refused . Sadly,
once monitor lizards have succumbed to infections they do not often recover. It is much
better to leave them to die in the shop than to buy them and encourage the proprietor to get
more. Wise dealers have monitor lizards screened for major parasites as soon as they are
imported, and add the bill to the animals' price. Even so they should still be subjected to a
normal period of quarantine after purchase.