The most common bacterial diseases in reptiles are:

• Septicemia
  Bacteria in blood which causes death
• Scale Rot
  Skin infection (seen mostly in snakes who live in high humidity)
• Abscesses
  Mucous discharge encircled by a sac (seen under the skin or inside the body).
• Star-Gazing
  Neurological symptoms caused by bacterial infection.
• Mouth Infections
  Seen in snakes, lizards, and turtles.
• Respiratory Infection
  Open mouth breathing will be seen.
• Ear Infection
• Cloacae Infection
  Inflammation of the cloacae because of an imbalance in the food's minerals and vitamins.
• Mycobacterium infection
  Tuberculosis (losing weight) can also infect people.

Protozoa Diseases

Ameba (Entamoeba invadens)
One of the most serious protozoa in reptiles.
Symptoms:
Not eating, losing weight, vomiting, and mucous or bloody diarrhea and death.
Diagnosis:
Isolation and identification of causative agent in fecal.
Treatment:
Antibiotics.

Giardia
One of the most serious protozoa in reptiles.
Symptoms:
Urinary and intestinal illness in reptile.
Diagnosis:
Direct fecal smear looking under microscope.
Treatment:
Antibiotics.

Fungal Disease
Poor husbandry, high humidity, low temperature, stress, and concurrent illness contribute.
Symptoms:
Skin lesions and respiratory infection.
Diagnosis:
Culture the skin lesion.
Treatment:
Anti-fungal agent.

METABOLIC AND ENDOCRINE DISEASES

Gout
An accumulation of urate either in particular surfaces of the joint or internal organs.
Cause:
Excessive protein in diet, dehydration, and kidney damage.
Diagnosis:
X-ray.
Treatment:
Medication, and diet in early stages works.