Herpesvirus is a serious viral infection of tortoises.

Herpesvirus spreads by direct contact between infected tortoises.

All European tortoises (Testudo species) may carry herpesvirus.  It is likely that each tortoise species has its own herpesvirus that causes minimal problems with them but which may be deadly when it gets into another species.

Aggressive medical management is necessary for treatment.  Despite even the best medical care, some tortoises do not survive.

Signs

Due to the lesions in its mouth and choana (the opening on the inside roof of the mouth allowing the nose to communicate with the windpipe), a sick tortoise is often reluctant to eat or drink, has a runny or crusty nose, has drool or a crusty mouth, has an audible whistle or gurgling nose while breathing, and may open-mouth breathe or gape. You may see white or yellow material lining the inside of the mouth and tongue. Other signs are closed or swollen eyes, lethargy, and hiding a lot. In rare cases, a tortoise may circle or have uncoordinated movement. Some tortoises die without obvious signs.

Who’s at risk?

All species of tortoises are susceptible to herpesvirus infection. However, it is commonly a problem with Russian tortoises (Testudo horsfieldii) and Greek tortoises (Testudo graeca spp.) that are still imported from the wild in large numbers. These animals are highly stressed and exposed to a veritable Pandora’s box of viral diseases from the different reptile species they are exposed to during collection, exportation, and reselling. Since herpesviruses can live quietly in a tortoise and erupt when the tortoise is under any stress, it can even cause illness in long-term captives. Even captive-bred tortoises have herpesviruses and may be asymptomatic carriers. There is no such thing as a Testudo that is guaranteed to be free of herpesvirus.

Why do some tortoises not get sick?

It seems likely that some herpesviruses evolved to live without harm in some tortoises. It is when a herpesvirus gets into a different species of tortoise that it causes this devastating illness. It is particularly deadly when it jumps to a different genus of tortoise, so I recommend that people with Testudo do not keep other tortoises unless they are able to practice strict quarantine to prevent cross-contamination.

What will you do with my sick tortoise?

We often recommend bloodwork and radiographs to assess the tortoise’s overall health. Although it is difficult to definitively identify herpesvirus, the clinical signs are classic in most tortoises. We will clean and debride the plaques lining the mouth and often flush the nose with an antibiotic and anti-inflammatory solution. This may be needed every 48 to 72 hrs. We start antiviral therapy with a drug called acyclovir. A prescription will be called in to a compounding pharmacy and delivered to your house by mail. In some cases, you may have to drive to the special pharmacy to start the drug as soon as possible. Only certain pharmacies make this special medicine. In addition, injectable antibiotics may be needed to manage bacterial infections that develop in areas damaged by the virus such as the mouth and upper airways. Tube-feeding and injectable fluids may be needed for nutritional support and pain relievers may be prescribed to help the tortoise feel better. Most tortoises need to have a feeding tube surgically implanted so that they can more easily receive oral medication and nutritional support. Some tortoises may need to be hospitalized so we may do more aggressive treatments such as daily debriding of the the mouth, regular fluid therapy, nebulization, and different antibiotics.

How should I house my sick tortoise?

A sick tortoise should be isolated so it may be carefully monitored. It is essential to keep the cage warm. A basking light, typically a 60-100 watt spotlight, should be set-up on one end of the tank. The temperature underneath the spotlight should reach 95-100°F. The cooler end of the cage should be about 15°F cooler. Use an infrared (laser) thermometer to directly measure the temperature of your tortoise. If it spends all its time under the light, the cage may be too cool. If it spends all its time at the cool end of the cage, the basking spot may be too hot. Some source of floor heat, such as a heat tape, is useful for night time heat. Ultraviolet-B light may stimulate healing. ZooMed’s Reptisun 5.0 UV Bulb or 10.0 UV Bulb and T-Rex Active UV Heat are excellent sources of ultraviolet-B light. They should be set up to illuminate the area around the basking light. The Active UV Heat can serve as the basking light. These bulbs need to be replaced every 6-12 months, even if they are still shining, because their ultraviolet output decreases over time. You should make sure your tortoise has a shallow water bowl for drinking and soaking. Daily soaks in warm water are essential to keep the tortoise well hydrated so that it will be stimulated to defecate or urinate.  Soaking is a way for the tortoise to loosen the crusts that form around the nose and mouth. Many tortoises benefit from a humidifier being run while they are sick as it helps keep nasal discharges moist and draining. Closely monitor appetite—if your tortoise is not eating, it may need tube-feeding or even surgical placement of a long-term feeding tube. It is also important to monitor urine and fecal output as some of the drugs used to fight infection may impact the liver and kidneys.

What are my tortoise’s chances?

A lot depends on how long your tortoise was sick before treatment was started and whether or not it has any other ongoing diseases such as parasites or malnutrition. Advanced cases where the tortoise has been sick long enough to lose weight carry a poor outlook. With early detection and aggressive care, over 90% of tortoises recover with proper care at home. If you have other tortoises in your home, it is likely that they have already been exposed to the herpesvirus, or were themselves the carrier that infected the sick tortoise, and should be closely watched for signs of illness.

How do I prevent the spread of the disease?

Isolate the sick tortoise and all tortoises that have had close contact with it. Chlorine bleach diluted 1 part to 30 parts water is very effective disinfectant for tools, water bowls, and cages. Outdoor enclosures with dirt and plants are likely contaminated for a year or more and should not be used to house clinically healthy tortoises. Wear disposable gloves or wash hands with warm water and soap after handling an infected tortoise. Do not wear the same shows when servicing an infected enclosure as when you service pens of healthy tortoises.