By Dr. Becker
If your snake, lizard or other reptile suddenly begins to turn his head upward as though he’s gazing at the stars in the sky, it’s a sign that something could be wrong with his central nervous system.
“Stargazing” in reptiles may be the result of a traumatic injury or can be a sign that your reptile was exposed to a toxic substance, has a problem maintaining body temperature or may be suffering from a bacterial, parasitic or viral infection.
Among the latter is inclusion body disease (IBD), a viral infection that affects boa constrictors and pythons.
‘Stargazing’ Is a Sign of Inclusion Body Disease
IBD is most common in boid snakes, which are those that kill their prey via constriction. Boa constrictors and several types of pythons are most often affected by the virus (IBD is thought to be caused by a retrovirus or an arenavirus).
It is seen only in captive snakes and likely spread around the world when infected captive snakes were transported in the pet trade or moved between different zoos.
Snakes may harbor the virus that causes IBD for many years without displaying any symptoms, so transmission could occur before anyone realized the snake was sick.
Stargazing is only one sign of IBD and may be preceded by other symptoms, especially in boa constrictors (Burmese pythons, on the other hand, may progress directly to central nervous system symptoms like stargazing):
Regurgitation (this may be one of the first signs of IBD in boa constrictors but does not occur in Burmese pythons) Abnormal shedding Anorexia (the snake stops eating) Weight loss Clogged nostrils
The following conditions may also occur with IBD:
- Stomatitis (mouth rot)
- Undifferentiated cutaneous sarcomas (tumors)
Further, according to Reptiles magazine, in addition to stargazing you may notice the following neurological signs as the infection progresses:1
“Pythons with IBD often develop neurological signs earlier than boas, and these signs are often more pronounced and obvious. Pythons don’t regurgitate as often as boas will.
Pythons often show a progressive loss of motor function, usually in the back half of the snake, which may lead to bloating and constipation.
Both boas and pythons may hold their tongues out longer when flicking. Chronic pneumonia in boids that is not responsive to antibiotic therapy and nebulization therapy may actually be IBD.
Some snakes with IBD are chronically shedding the virus and are capable of spreading it throughout a collection, before clinical signs of the sick snake are realized.”
How Is Inclusion Body Disease Spread?
IBD is thought to spread through the transfer of bodily fluids. So breeding, fighting (with bite wounds) and fecal/oral contamination, may all spread the virus.
The virus may also be transmitted from a mother to developing embryos, and the snake mite (Ophionyssus natricis) has also been suggested as a potential vector, as infected snakes often suffer from mite infestations as well.2
If your snake is showing signs of IBD, veterinary care will be essential. While diagnosis can be made based on signs and symptoms, this isn’t recommended because other diseases can cause similar symptoms.
A blood test and tissue biopsy may be required to properly diagnose IBD. Inclusion bodies (pockets of foreign materials in cells) are often (though not always) seen on blood smears taken from infected snakes, which is where IBD got its name.
Inclusion Body Disease Has No Known Cure
IBD is not currently curable, although infected snakes can be kept alive by force-feeding and supportive care. Because the virus can suppress your snake’s immune system, secondary bacterial infections may also occur and must be controlled.
That being said, an infected snake may still succumb to the disease and can infect other snakes, so must be quarantined.
Any time you introduce a new snake into your home, you should quarantine him for a minimum of 90 days prior to introducing him to other snakes.
If you’re bringing a boa constrictor home, a quarantine period of six months is recommended to ensure he is free of the virus. Controlling snake mites is also essential and may help curb the spread of IBD.
If you’re planning to reuse a habitat from a snake infected with IBD, be sure fiberglass cages are disinfected thoroughly with bleach and dried in the sun prior to reuse. Wood cages and/or habitat decorations should be disposed of.4
What About Stargazing That’s Not the Result of IBD?
While stargazing in the snakes mentioned is often due to IBD, stargazing in lizards such as the bearded dragon may be the result of atadenovirus (ADV, sometimes called adenovirus). ADV-positive dragons often have serious parasitic infections and liver and intestinal damage. If the virus spreads to the brain and spinal column it can cause neurological symptoms including seizures and stargazing.
Stargazing caused by bacterial or parasitic infections may be successfully treated, especially if the infection is caught early on. In such cases, proper diet, a clean habitat and non-stressful living conditions may help your reptile recover and prevent a recurrence.
As mentioned, if your reptile is “stargazing,” there is some type of underlying infection, trauma or toxic exposure causing this neurological symptom. Supportive care from a knowledgeable reptile veterinarian will be essential to helping you determine how to best care for your pet.