Acute Gastric Dilatation
Life-threatening bloat occurs sporadically in captive primates and may be associated with feeding following a prolonged fast or periods of water restriction or accidental overfeeding. Etiologic factors include intragastric fermentation associated with Clostridium perfringens and abnormal gastric function. Monkeys become acutely ill with clinical findings similar to those seen in small animals (see Gastric Dilation and Volvulus in Small Animals). Acute gastric dilatation is often fatal unless emergency treatment is given. The stomach must be evacuated and fluids replaced, in like volume, with electrolyte solution given parenterally. Shock and dehydration usually occur and require prompt treatment. Periodic evacuation of the stomach may be necessary for several days until GI function is normal. Metabolic alkalosis may result from continued loss of hydrochloric acid. Adequate sodium, chloride, and potassium must be provided via parenteral fluid therapy.
Infection with Clostridium tetani is a risk with free-ranging and outdoor-housed monkeys, particularly as a consequence of fighting, parturition, frostbite, and other forms of skin trauma. Immunization with tetanus toxoid should be considered for populations at risk. (Also see Tetanus.)
The number of aged nonhuman primates maintained in captivity has increased in recent years, primarily due to improvements in husbandry, nutrition, and veterinary care, but also due to an emphasis on animal models for aging research. This increase in the aged primate population, particularly macaques, has been associated with an increase in the incidence of intestinal adenocarcinoma, which may exceed 20% in animals >30 yr of age in some colonies. Decreased appetite, weight loss, anemia, and a palpable abdominal mass are common clinical findings. Tests for fecal occult blood are often positive. Radiographic examination may show changes associated with partial obstruction. Surgical biopsy is diagnostic for adenocarcinoma. The location of these tumors is most commonly the ileocecocolic junction, rarely in the small intestine. Histologic lesions include a thickened intestinal wall and constriction of the lumen (so-called “napkin ring” lesion), with variable signs of hemorrhage and ulceration. Metastatic lesions are uncommon, and some animals respond favorably to surgical excision.
Trauma from cagemate aggression or self-mutilation (biting or hair pulling) may occur occasionally, as may thinning of the hair due to self-induced alopecia. Massive soft tissue injury, such as that which occurs from mob attacks, causes release of intracellular contents (ie, hypercreatinemia, hyperkalemia) leading to renal failure and death. High-volume fluid therapy is indicated to avert renal shutdown, and antibiotics should be given to prevent infection and sepsis. While measures should be taken to enhance the psychologic well-being of primates—such as group housing, exercise pens, shelters, foraging activities, and cage toys—animals in social groups should also be provided facilities for refuge and escape.
Last full review/revision July 2011 by Nicholas W. Lerche, DVM, MPVM