In Beirut, Lebanon, one–third of 300 mature swine were found infected with hydatid cysts by routine meat inspection. During the same period of time, about one–third of the cattle and one–fourth of the sheep and goats also harbored infection at slaughter. Identification of cysts from these animals was confirmed by microscopic examination in the laboratory.
Two–thirds of a second group of 54 older swine harbored cysts in either the heart, liver, or lungs as shown by superficial examination and by serially slicing these organs and microscopic examination of samples of the contents of all gross lesions found.
The average number of hydatid cysts per animal was 1.4 and 8.1 for the two groups respectively. Twenty-one percent of the cysts in the second group were deep in the lung and/or liver tissue and not visible superficially.
Almost 20% of the infected swine had fertile cysts but there were relatively few viable scolices therein.
Microscopic examination of some cysts of different sizes indicated that a majority were in stages of degeneration and were being invaded by host cells.
The condition of the cysts combined with the limited numbers of swine slaughtered show that this animal is not an important host of hydatid infection in Lebanon but that it remains the only indicator of the high level of cystic hydatid infection acquired locally. Thus, it may be of value in determining the efficacy of control measures.
Laboratory of Parasite Chemotherapy, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland.