Fig. 28.2 Armillifer armillatus. The semicircular and coiled outlines of numerous larvae are clearly seen along the peritoneum and mesentery of an African monkey. The larvae have a similar appearance in humans.

Fig. 28.3 (A) A single Armillifer armillatus larva seen in its typical "C" shape or horseshoe configuration along the peritoneal surface of the liver. AFIP 69-3965-1. (B) Unencapsulated nymph of A. armillatus attached to the abdominal aspect of the diaphragm of an African patient (gross, X 4). (Courtesy of Dr. Daniel Connor, from D.H. Connor and F.W. Chandler (eds): Pathology of Infectious Diseases. Appleton & Lange, Stanford, Conn., 1997).

Clinical Characteristics

In the majority of patients, there are few or no symptoms attributable to the infection and most patients are totally unaware that they harbor the parasites. However, in a heavy infestation, the migration of many live larvae beneath the peritoneum or pleura may cause sufficient irritation and pain to mimic an acute abdominal condition or pleurisy. Many surgeons in Africa have performed laparotomies on patients with an "acute abdomen" only to find, to their chagrin, live wriggling worms beneath the peritoneum. The majority of the larvae lie in the subperitoneal tissue, especially around the liver and spleen, or in the mesentery (Figs. 28.2 and 28.3). Pneumonitis, bronchitis, pleuritis, pericarditis, hepatitis and peritonitis have been noted in patients with severe infection. Intestinal obstruction has occasionally been ascribed to the fibrotic bands resulting from the dead cysts.

Smith and his colleagues noted in a 1975 survey of 2,764 autopsies that patients who died of a malignancy had a 33% rate of pentastomiasis whereas the rate in nonmalignant autopsy cases was 16%, a difference that appeared to be statistically significant.