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Salmonellosis In Reptiles

Introduction:

Salmonella sp. is the most common organism of zoonotic concern in reptiles. Salmonellae are Gram-negative, aerobic and facultatively anaerobic, non-spore forming and mainly motile rods. These bacterial organisms can cause a wide spectrum of disease, ranging from gastroenteritis, enteric fever, bacteraemia, focal infections, to a convalescent lifetime carrier state.

Salmonellosis has enjoyed a lot of attention over the last few years. Although this disease does not cause nearly as much problems in humans when compared to food borne Salmonella infections, it is still potentially dangerous and can cause serious disease and even death in a significant percentage of the human population.

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Important Salmonella Serotypes & Groups:

All Salmonella serotypes are members of only a very few Salmonella species. Most is part of the species Salmonella enterica. At the time of writing, there were already more than 2 500 serotypes described. These serotypes are accepted as pseudo-species. The following table lists the more important serotype mentioned in this section:

Species	Serotype	Hosts
S. enterica	Typhi	Humans
	Paratyphi	Humans
	Typhimurium	Humans, zoonosis
	Enteritidis	Humans, zoonosis
	Cholerae-suis	Humans, porcines, zoonosis
	Dublin	Humans, bovines, zoonosis

Salmonella serotypes are then classified according to their adaptation to human and animal hosts.

Group 1, also called Typhoidal Salmonella, e.g. S. Typhi and S. Paratyphi, causes enteric fever only between humans or between higher primates. This form is usually contracted through direct contact with the fecal matter of an infected person. It is the rarer form of Salmonella. Because the members in this group are species specific, they are not considered zoonoses.

Group 2, causes disease in certain animals, e.g. S. Dublin in cattle and S. Cholerae-suis in pigs, but rarely in humans. However, when these strains do cause disease in humans, it is often invasive and can be life-threatening.

Group 3, also called the non-Typhoidal Salmonella, includes the remaining strains. Typically, these strains cause gastroenteritis which is often mild and self-limiting but can be severe in the high risk group. S. Enteritidis and S. Typhimurium are the two most important strains for salmonellosis transmitted from animals to humans. This group is responsible for most animal-borne infections in humans.

Salmonella organisms most commonly causes food poisoning, with, as mentioned earlier, the majority of cases caused by S. Enteridis and S. Typhimurium. This bacteria poses huge economic implications in the food industry especially developed countries. It is mainly contracted through consumption of raw or undercooked contaminated food (meat, poultry, eggs and milk).

These organisms can also be contracted by direct contact with live and dead animals, such as Bearded dragons.

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The Facts About Salmonella In Reptiles:

It must be emphasised at this point that the threat of contracting salmonellosis from a reptile is not nearly high as with for example being exposed to and eating contaminated food. However, it is real and a rapidly emerging threat none the less. Because of its serious implications it is well worth preventing instead of ignoring.

It was estimated that 3 � 5% of all cases of human salmonellosis are associated with direct or indirect contact with exotic pets.

Reptiles are asymptomatic carriers of Salmonella organisms and shedding is intermitted, i.e. one animal do not permanently excrete the organisms. In at least one study it was determined that Salmonella could only be isolated from faeces or skin swabs and never from the inside or the outside of the terrarium walls, meaning there is no epidemic transfer from one terrarium to the next (i.e. terrariums in close vicinity). Animal to animal transfer could also not be established and in some instances animals were tested positive while their cagemates were negative and different strains were isolated from different cagemates.

In one study, which was also interested in the susceptibility of the bacteria to various antibiotics, various strains of S. Enterica were isolated from 23.93% of the faecal samples from tested reptiles. Considering the number of samples taken for each reptile group, S. Enterica was isolated from the 36.58% of chelonians, 26.66% of saurians and 14.14% of ophidians.

In another study different strains and types Salmonella was isolated from 24% snakes, 17% saurians and 3% turtles. In this study it was also noticed that the incidence of isolating the bacteria increased significantly over the few years the study were conducted, i.e. newly introduced reptiles showed less positive results compared to animals that were in captivity for two or three years.

It should be emphasised that because of the fact that it was proven that the incidence can increase over time and that Salmonella is intermittedly excreted, the abovementioned statistics should not be used to determine risk. All Bearded dragons should be considered carriers and should be handled accordingly.

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Transmission Of Salmonellosis:

Zoonotic diseases from animals are usually transmitted to humans by direct contact. After initial transmission to in-contact surfaces, such as the skin, these organisms are spread to the mouth or other mucous membranous surfaces like the eyes and nose where they potentially enter the new host.

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Symptoms Of Samonellosis:

Symptoms in infected humans include diarrhoea, fever, vomiting and abdominal cramps as early as twelve but up to seventy two hours after contact. In most cases the illness lasts for three to seven days. Most affected persons recover without treatment, however, in some cases the diarrhoea may be so severe that the patient becomes dangerously dehydrated which will need intensive hospital treatment. Hospital treatment includes intravenous fluids / drips, antibiotics and symptomatic medication to relieve pain, fever and vomition.

In severe cases the patient may become septicaemic (where the infection and its toxins spread from the intestines to the blood stream and then to other body organs) which can cause death unless the person is treated promptly with antibiotics. Persons in the high risk group mentioned earlier are more likely to have a severe illness. Some people afflicted with salmonellosis later experience reactive arthritis, which can have long-lasting, disabling effects.

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High Risk Group:

Anybody coming in direct contact with reptiles and who ignores the preventative measures are prone to zoonotic diseases. People that are in the higher risk group include pregnant women, very young, old and immune compromised people like HIV positive and cancer patients. Children less than five years of age are recommended not to come in direct contact with these animals as they are very prone to get diseases when present.

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Prevention / Risk Reduction Of Samonellosis:

All exotic animals should be considered carriers of zoonotic diseases.
The high risk group should reduce or prevent any direct or indirect contact with exotic reptiles, including supervision of children.
The handler should washes his / her hands and arms with a commercial, antiseptic soap after any contact with a reptile, its food or cage decoration and substrate.
Kitchen sinks, bathtubs and washbasins should be washed thoroughly and disinfected after bathing a Bearded dragon or using it to wash terrarium furniture.
Reptiles should never be allowed to roam freely in the living areas where people might be contaminated. It is more important to keep these animals out of kitchens and other food-preparation areas.
All people coming in direct or indirect contact with reptiles should be aware of the risks and behave accordingly.

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"If you think I should add more information to this section or think that something is incorrect, contact me and let me know. I would love to hear your ideas or methods you might use that is different than ours."

Last updated 9 February 2009 by Renier Delport

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"Always remember only to buy healthy animals from reputable pet shops and breeders. Make sure to buy animals that are captive bred in your own country and that it is not illegally imported or caught from the wild."