COMPARATIVE PATHOLOGY IN EXPERIMENTAL INFECTION OF PIGS AND CALVES WITH LARVAE OF ANGIOSTRONGYLUS CANTONENSIS

Angiostrongylus cantonensis infection was produced experimentally in pigs and calves by the oral administration of third-stage larvae. Living and normal third-stage larvae, without evidence of further development, were isolated from the visceral organs of a pig at 3 days and of calves at 3, 7, 14 and 28 days after dosing. Larvae recovered 3 days after infection from the stomach of a pig, and from the lungs, peritoneal and thoracic cavities of a calf, produced cerebral infection when fed to rats. A few which appeared normal and were recovered from the lungs of calves 7 to 28 days after infection failed to produce cerebral infection when fed to rats in small numbers. It is not known to what extent these results were due to the comparatively few larvae which were fed to the rats. In pigs, larvae, in process of disintegration, were found enclosed in granulomas in the wall of the digestive tract and in mesenteric and mediastinal lymph nodes. A characteristic form of interstitial focal hepatitis also developed during the second week of infection. In calves, the larvae were found mostly in the pulmonary lymphatics and in mediastinal lymph nodes. The granulomatous reaction was delayed and several larvae, apparently morphologically intact, were found in the lungs as late as 28 days after infection. Unlike the pigs, no interstitial focal hepatitis developed in any of the calves. In one pig and in all five calves, some of the larvae migrated and developed to the fourth-stage in the central nervous system. The lesions are described. © 1968.