There are many different species of adenovirus that infect reptiles, and while most of them seem to infect only one species, some adenoviruses can infect more than one type of reptile. Bearded dragons, chameleons, kingsnakes and blue-tongued skinks are most commonly infected by adenoviruses.
The genus Atadenovirus is composed of a number of different virus species that infect specific types of reptiles:
- Agamid adenovirus 1 (bearded dragons, which is the most widespread in the U.S.)
- Chameleonid adenovirus 1 (chameleons)
- Eublepharid adenovirus 1 (leopard geckos and fat-tailed geckos)
- Gekkonid adenovirus 1 (other gecko species)
- Helodermatid adenovirus 1 (Gila monsters and Beaded lizards)
- Scincid adenovirus 1 (blue-tongued skinks)
- Snake adenovirus 1 and 2 (different snake species like kingsnakes).
Another genus, Siadenovirus, infects the Sualwesi forest turtle, and there are a few new ones that infect other turtles and tortoises. The only types of reptiles that have not been seen to have adenovirus infections are alligators and crocodiles.
Being infected with an adenovirus commonly causes stomach, intestine and liver problems; less common issues include kidney, bone marrow and brain disease.
Young, old and stressed animals appear to be at the greatest risk of getting the disease. What is commonly seen is young animals that fail to thrive and grow well, have high death rates, don’t eat well, and often lose weight.
However, it is possible that an animal infected with adenovirus will not be sick but can still spread the disease. These animals are known as carriers and can be a problem for the other animals in the collection. We don’t know how common this carrier state is, so collections that regularly have lots of new animals are also at greater risk of introducing the disease to the other animals.
Transmission is through the fecal-oral route, i.e., coming into contact with reptile’s feces, which can then go in the mouth.
There is no known risk of infection to humans from reptile adenoviruses, so you don’t have to worry about people.
It seems that almost any reptile can be infected except crocodiles and alligators. The adenovirus that infects bearded dragons (Agamid adenovirus 1), seems to be wide-spread in captive bearded dragon populations in the U.S.
Reptiles with an adenovirus infection are usually just sick. They have non-specific signs, or what pet owners sometimes call “ain’t doing right.” This means that your animal has signs of illness that could have many causes. Your veterinarian will start by taking a thorough medical and husbandry history and give a physical examination. Your reptile will also have blood taken for a complete blood count and plasma chemistry in addition to X-rays.
There are now a few specific tests to determine if your reptile has an adenovirus infection; both are polymerase chain reaction (PCR) tests. The two that are available are called nested PCR and real time PCR (also called RT-PCR). The best sample for this test is from the cloaca, and it’s often called a cloacal wash. A wash does not require sedation.
Unfortunately, there is no specific treatment. Supportive treatment measures include fluids, antibiotics, and force feeding. Feeding tubes can also help, and can be the red-rubber catheter or metal ones of the appropriate size. We don't know which reptiles might respond, and it may not help at all.
To help with recovery, reduce stress by not handling your reptile during treatment, and make any husbandry changes suggested by your veterinarian.
Many reptiles that survive an infection with adenovirus become carriers and can still transmit the disease to others. Discuss this with your veterinarian.
One drug that could be used for treating infections with adenovirus is called cidofovir. This drug has been found to be effective in treating mammals, so you can discuss this with your veterinarian.
The goal is not to allow the disease to enter the collection. Quarantine monitoring is critical: all reptiles coming into a collection should have a PCR test performed for adenoviruses before they join the collection.
Using separate clean utensils for each cage and washing hands between cages and handling of animals is essential as the main mode of transmission is transferring the feces of infected animals to uninfected animals on cleaning tools or owners’ hands.
Providing a stress-free environment and the best husbandry practices are the most important aspects of preventing adenoviral disease.
Adenoviruses are hard to kill in the environment and so disinfection is difficult to achieve.
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