PetVet: Snake's eyes prompt an unusual question

September 23, 2013


When people think of veterinary medicine and the scope of species we as veterinarians serve, I suspect dogs, cats, horses and perhaps "food" animals top that list. There are however many different species of animals that people choose to care for as companions and there are veterinarians that do indeed work with some of these more "exotic" species. Bando would fall into this category.

Bando is a 3-year-old, 6½-foot snake — and not just any kind of snake. He is a wart snake or sometimes called elephant trunk snake. Bando’s caretaker, Randy, has had Bando for two years, having purchased him from a California reptile dealer.

He is housed in an aquarium that is temperature-controlled and aquatic. Bando spends almost all of his time in the water, including feeding time. His diet consists of goldfish and he is feed once a week. Randy reports that Bando has had no problems in the past two years but recently appears to have developed an issue with his eyes.

Over the past few weeks, Bando’s eyes have become more and more opaque. They are now to the point where Randy suspects Bando cannot see.

Initially Randy thought Bando’s eyes were clouding over as they normally do right before he sheds his skin but even after a shed occurred, the opacity in Bando’s eyes remained. Randy has yet to find a veterinarian to examine Bando so he took to the internet and eventually got me involved.

To understand what might be going on with Bando’s eyes, it helps to understand a bit about the natural history of his species. For you aficionados, wart snakes belong to the genus Acrochordus, which includes three species of snakes. I suspect Bando is a Java wart snake because of his large size.

These snakes are native to parts of southeast Asia and spend most of their time in water. Their diet consists of aquatic life -- especially fish -- and they have a rough scale pattern, which aids in gripping fish as they coil around them when eating. In my clinical experience, these are very rare snakes in captivity. I personally have only worked with them in zoo collections.

There are many possibilities that could cause Bando’s eye issues. But it is my suspicion that Bando’s eye problem is directly related to his captive environment and, more specifically, the water he is kept in. In their natural habitat, wart snakes live in water that is brackish. This type of water is between fresh and salt water in its salinity, and occurs in areas where salt and freshwater mix.

Areas such as the mouths of streams and rivers are prime habitat for this snake. In captivity, it is sometimes difficult to maintain the proper salinity of the water in which these snakes are housed and often times people will simply use fresh water. Overtime, this can lead to an eye problem called corneal edema. I believe Bando has developed corneal edema.

Remember back in school when you learned about osmosis? It is a term given to the movement of water across a membrane from an area of greater concentration to an area of lesser concentration.

In the case of Bando’s eyes, the concentration of water is higher outside the eyes than inside and the water molecules then move across the corneal membrane into the eyes causing the observed opacity and swelling as well. This condition is completely fixable if addressed in a timely manner by making sure Bando’s water is brackish.

This can be done by adding a proper amount of salt mixture. I recommend the products used for saltwater aquariums, but at two-thirds the normal concentration. Once the salinity is balanced, Bando’s eyes will clear as the water that has swelled and clouded his eyes moves in the other direction, again by osmosis, out of his eyes.

It is very important to address this water change as soon as possible otherwise, left untreated, Bando’s eyes will become permanently damaged.

 

 


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