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What is URTD.
Upper Respiratory Tract Disease (URTD) is a contagious bacterial infection that affects gopher tortoises and several other tortoise and turtle species. The disease is caused primarily by
Mycoplasma agassizii and Mycoplasma testudineum—bacteria that attack the tissues of the upper respiratory system and lungs.
Clinical Signs
& Symptoms.
Mycoplasma infection can significantly affect a tortoise’s normal behavior, including feeding, burrowing, and basking habits. Infected gopher tortoises may lose their appetite, become lethargic, or bask at unusual times of day. Over time, these changes can lead to malnourishment, dehydration, and increased vulnerability to other illnesses or even death.
Common signs of URTD infection include:
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Runny nose
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Watery eyes
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Swollen or sealed eyelids
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Redness in the inner corner of the eyes
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Wheezing or raspy breathing
However, not all infected tortoises show visible symptoms. Some individuals may carry and spread the bacteria without displaying any outward signs of illness.
Mortality.
Mortality from Upper Respiratory Tract Disease (URTD) can occur when infection severely weakens a gopher tortoise’s health or when symptoms persist over long periods. Infected tortoises often stop eating and become lethargic, leading to malnutrition, dehydration, and a weakened immune system. As their condition worsens, they may spend less time in their protective burrows, leaving them exposed to predators and harsh environmental conditions. These changes can lead to rapid weight loss, dehydration, and a weakened immune system, making them more susceptible to predators, parasites, and environmental stressors.
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​Although not every tortoise with URTD dies from the disease, chronic infection can cause long-term health decline and eventual death—especially during periods of environmental stress such as drought or habitat loss. In populations already struggling with fragmentation or low numbers, even a small increase in mortality can have major consequences for recovery and survival.
Because some tortoises carry the bacteria without showing symptoms, the disease can spread silently, making it difficult to predict or control outbreaks. Over time, URTD-related deaths can reduce population stability, alter social structure, and threaten the long-term viability of local colonies.
URTD Research.
Ongoing research on Upper Respiratory Tract Disease (URTD) aims to better understand how the disease spreads, how it affects tortoise populations over time, and what factors make certain individuals or colonies more vulnerable. Wildlife biologists and veterinarians study Mycoplasma bacteria using blood tests, DNA sampling, and long-term population monitoring to track infection rates and identify carriers that show no symptoms.
Researchers are also exploring how stress, relocation, and habitat disturbance may trigger or worsen outbreaks. Health assessments are now a key part of relocation and rehabilitation programs, helping prevent the unintentional spread of URTD to healthy populations. These studies are essential for developing effective management and recovery plans to protect gopher tortoises across their range.