Lizard and Snake Zoonoses

Lizards and snakes present problems to handlers and owners not just because of their venom and size but also due to the possibility of zoonosis. Care must be taken with all lizards when they are handled even if they are not perceived as dangerous. Consider the following points.

Zoonoses

The common zoonosis associated with reptiles is salmonellosis. Subclinical infections of reptiles are common and the Salmonella spp. can often be isolated from faeces. However, most reptiles naturally carry these bacteria as a component of their indigenous gut flora, and they are rarely a cause of primary disease. Over 2400 different serotypes of Salmonella spp. are known and all should be considered pathogenic.

• Pregnant women, children under five years and immunocompromised persons should avoid contact with reptiles and reptile implements
• The CDC recommends that reptiles should not be kept in child-care centres and households in which persons at risk reside
• Provide information to potential purchasers and owners about the risk of acquiring salmonella
• Proper hygiene measures should be conducted around reptiles at all times
• Reptiles should be kept out of sites where potential for transmission exists

Salmonella spp. is the most important zoonotic agent. Reptiles can also harbour several different opportunistic Gram-negative bacterial pathogens that can infect humans. These include Aeromonas, Campylobacter, Enterobacter, Klebsiella, Erysipelothrix rhusiopathiae, Pseudomonas, Mycobacterium spp., Coxiella burnetti, Chlamydophila psittaci, Aspergillus, Zygomycosis, Candida, Trichosporon, Trichophyton and ticks. These potentially zoonotic diseases can be managed by practicing routine hygiene practices.

Hygiene

The majority of reptile-related salmonellosis reported in humans could be avoided if common sanitary practices were followed. Washing hands with soap is an effective method to remove Salmonella spp. organisms and minimize contamination of the environment. Disinfectants, such as sodium hypocholorite, should be used to disinfect the snake's enclosure including food and water dishes, and other cage furniture.

Considerations for Snakes

Constrictors

Large constrictors should only be handled when there are two people present. They are extremely powerful and a single handler is in danger of injury, even death. There may also be legal considerations regarding the possession of dangerous animals so ascertain that these are fulfilled.

Venomous snakes

Venomous snakes should obviously only be handled by experienced personnel with appropriate equipment and preferably be treated by experienced veterinarians. Proper identification of any venomous snakes is of the utmost importance. In case of a human bite, it is necessary to have access to antivenin. A veterinarian working with venomous snakes needs to be aware of the laws regarding dangerous animals. Possession of venomous snakes is regulated so make certain that the owner has the appropriate licences. Also check with the appropriate authorities if you, the veterinarian, need to be specially licensed to treat or house venomous snakes.

• At least two people should always be involved in handling a venomous snake
• Large, obvious signs that read "VENOMOUS SNAKE" should be placed on the outside of the enclosure
• An emergency telephone with essential contact numbers should be located nearby of venomous snake enclosures
• An antivenin protocol should be developed with a local hospital

Useful resources

• Snakebite Introduction (invenomation treatment) - The Merck Veterinary Manual
• Zoonoses - WHO