Colds and Respiratory Infections: Respiratory infections and colds are usually the direct result of improper care - drafts, cold bathing water, excessive temperature changes, and excessive humidity. Symptoms include nasal discharge, weeping eyes, coughing, wheezing, and sneezing. Most reptilien colds require treatment with antibiotics prescribed by your vet, because generally you won't notice the symptoms until the animal has become quite ill.
Mouth Rot (Stomatitis): Mouth rot is probably the worst bacterial infection in reptiles, and unfortunately is the cause of many an animal's loss. Bacteria of the groups Pseudomonas, Aeromonas, and Proteus accumulate in the oral mucous membrane and cause infections, swellings, and a cheesey discharge. Most cases of mouth rot occur after an initial injury to the snout and poor physical condition of the lizard. Early stages of mouth rot can be diagnosed if you notice the mucous membranes along the teeth and along the lips show a bright red inflammation. If you suspect your animal is infected, see your vet immediately. Proper diagnosis and treatment is best administered initially by your vet and can usually be continued at home.
Fungal Infections: Spread quickly and cause skin damage in reptiles that are generally kept in overly moist and warm enclosures. Infections usually start along the abdomen and produce raised brown-spotted scales. Further spreading causes open, weeping wounds in the skin. The fungus responsible for the infection must be diagnosed by your veterinarian who can then prescribe the proper treatment. Any lizard infected should be placed into quarrantine and kept there until the infection is stopped. Before placing the animal back into it's normal enclosure, the entire enclosure needs to be disinfected (including all decorations and contents) and treated with antifungals.
Worm Diseases: Worms are invertebrate animals that live parasitically in a host animal. They can include flukes, tapeworms, and spiny-headed worms. Many of these go through several stages of development while inside your animal and infected areas change when the stages change. To treat worms properly, a fecal exam must be performed by your veterinarian. First, this will determine what type of worms (if any) are infesting your animal, and second, proper medications can be prescribed and administered. Fecal exams should be performed regularly on all your animals, mine all get one at least once a year.
Mites and Ticks: Mites are small spider-like animals with four pairs of legs and biting or sucking mouth parts. Reptiles in general are typically infested with "blood mites" (Ophionyssus) that settle in the armpits, joint areas, base of the tail, around the eyes, in the vent area and underneath the scales. They are reddish-brown in color and if left untreated can cause skin damage and also transmit many other bacteria . They live under most and warm conditions and reproduce rapidly. If you notice your reptile rubbing or scratching along rocks and branches and it is spending an unusually long time in their water container these could be signs of a mite infestation. Examine your animal closely looking for the mites. There are several products on the market made specifically for eradicating mites. Again, call your veterinarian for the best advice on treating your particular animal and it's environment. Ticks are most often found on wild-caught animals or animals housed outside. They are removed easily by first dabbing their body with rubbing alcohol, waiting a few minutes, and then gently but steadily pulling them free with tweezers. Don't jerk them off; you want them to come off with their mouthparts intact. Dab a small amount of alcohol on the puncture mark left after removal.
Metabolic Bone Disease (MBD or Avitaminosis): Caused by insufficient diet (lack of a variety of healthy foods), lack of food supplementation with calcium and vitamins made specifically for reptiles, and lack of full spectrum flourescent lighting in the enclosure. Indications: softening of the bone, loss of teeth, repetitive bone fractures, paralysis, convulsions, digestive problems, skin changes (such as loss of color, spots, cracks), shedding problems, eye problems (including clouding and swelling) and various other infections of the skin and internal organs
Vitamin Excess (Hypervitaminosis): Anyone under the impression that pumping your lizard full of vitamins is doing it a favor is totally wrong! Too many vitamins can be fatal. Dosages that are consistently too high can sometimes lead to damage as serious as that caused by not enough vitamins. Excessive Vitamin D can cause the onset of calcification of the arteries and uncontrollable bone and cartilage growth can occur. Too much Vitamin A can cause uncontrollable bleeding in the internal organs. Check the label of your vitamins for proper dosage; if you're unsure, check with your veterinarian
Digestive Problems: Improper diet can sometimes lead to diarrhea and similar digestive disturbances. Injuries to the tongue and upper jaw where the taste and olfactory organ (Jacobson's organ) is located make the animal incapable of finding its own food. Any diet issues should be discussed with your veterinarian when a change in diet is required.
Gastritis and Enteritis: Gastritis is an inflammation of the stomach lining and enteritis is an inflammation of the intestines. It can sometimes occur at the same time your animal has mouth rot. Affected lizards can have simple inflammation of the gastric and intestinal mucous membranes, to widespread abscesses and swellings or ulcerations. Typical symptoms include vomiting of half-digested food and soft (diarrhea-like), foul-smelling feces, combined with a yellowish white mucus. Sometimes there are also traces of fresh blood in the urates. A bacteriological exam by your vet will need to be performed.
Sources: most of the info in this post was copied from http://www.animalhospitals-usa.com
some small pieces may have also been copied from http://www.popularpets.net