Metabolic Bone Disease (Fibrous Osteodystrophy):The most common disease of captive iguanas result from gross malnutrition. Most new iguana owners are not given proper dietary counseling when they buy their iguana. In fact, many are given incorrect information. The most common mistake is feeding lettuce (usually iceberg lettuce) to the exclusion of other important dietary items (see the section on Diet). Lettuce provides adequate amounts of moisture but is a nutritionally barren food otherwise. The problem is often aggravated by Vitamin D3 and calcium deficiencies which result from inadequate exposure to direct sunlight or artificial ultraviolet light and lack of vitamin-mineral supplementation. Signs of fibrous osteodystrophy include general listlessness, an enlarged, swollen lower jaw, difficulty in eating and markedly firm, swollen limbs and tail. Unfortunately, these desperately ill iguanas appear well-fed and chubby, and veterinary care is not often sought until it is too late.Sometimes the back, tail or legs are fractured or deformed. These problems usually receive more immediate veterinary attention.
Iguanas with metabolic bone disease should be treated by a competent reptile veterinarian. If the patient refuses all food offered except lettuce, the lettuce must be top dressed with a suitable vitamin-mineral powder. Iguanas of sufficient size may be given the supplement directly in filled gelatin capsules, as described above. Iguanas that have become "lettuce junkies" (consume lettuce to the exclusion of other foods) must be encouraged to accept and feed on more nutritionally complete food items. Some iguanas accept items that resemble lettuce, such as spinach and beet greens, and then may be more accepting of other foods offered. Another way to wean an iguana from lettuce involves sprinkling the more nutritious items (cut up in small pieces) over the preferred lettuce leaves. Usually the iguana will feed on both simultaneously. With each feeding, the proportion of nutritionally superior food items should be increased and the amount of lettuce decreased until the iguana has fully accepted a more nutritious variety of food. After 1-2 weeks, a vitamin-mineral powder can be sprinkled over the food to ensure nutritional adequacy. If such a product is used during the transition period, it may cause the iguana to refuse all food, including the lettuce. This would be undesirable.
Rear Leg Paralysis: A disease resulting from vitamin B1 deficiency causes paralysis of the rear legs and tail. This problem is treated with injectable B vitamins and dietary improvement, including vitamin-mineral supplementation. Rear limb paralysis may also result from mineral (especially calcium) deficiencies that cause fibrous osteodystrophy of the spinal column. injectable calcium is also necessary in the therapy of this problem.