In 221 patients (0.48% of hospital admissions) with hydatid disease (122 female and 99 males), 81% had single and 19% multiple organs involved. Lungs, liver and spleen as single sites of echinococcosis together represented 83.24% of cases and the liver alone represented 95.24% of instances with multiple organ involvement. One hundred seventy-nine single and 74 multiple cysts (ratio of 2.42/1) represented a total of 363 cysts (1.64 cysts/patient). The incidence of intact cysts was 51.52% and 48.48% had ruptured. Ruptures numbered highest in the lungs (73.44%) and greater in multiple (79.66%) than in single cysts (68.12%). In the liver, 27.14% of single and 54.55% of multiple cysts (40.44% of all liver cysts) had ruptured. Cysts varied in size from 0.8 to 35 cm diameter. Single cysts averaged significantly higher (14.16 cm) and multiple ones lower (5.71 cm) as did intact (6.75 cm) versus reptured cysts (4.33 cm). Except for 10 silent and 15 symptomatic cysts treated medically, all the rest were treated surgically by removal of the endocyst or resection of both endo and exocysts including 205 first, 31 second and 5 third procedures (1.75% of all major operations). Complications occurred in 28.57%. Surgical mortality (3.57%) was markedly lower than with conservative treatment (60%) and significantly less than that of the whole group (14.48%).

Rupture of the hydatid cyst in man brings about mild to severe toxic reactions including death. The present study was undertaken to investigate some of the responses resulting from administration of the ovine hydatid fluid to the sheep, which, like man, is an interme diate host of the Echinococcus granulosus. In 50 sodium pentobarbital-anesthetized sheep, the arterial blood pressure (A.B.P.), •central venous pressure (C.V.P.), respiration and electrocardiogram were recorded. Intravenous administration of 5-10 ml hydatid fluid brought about moderate to severe fall in A.B.P. and rapid respiration with or without transient apnea or permanent respira tory cessation in 80 percent of the animals. Fifty percent of the sheep died of circulatory and respiratory failure after the first injection of the hydatid fluid. Boiled hydatid fluid did not lose its potency to evoke the above responses. Pretreatment of the animals with atropine sulfate, 0,5 mg/kg subcutaneously, did not block the reactions. Administration of the antihistamine chlorpheniramine, 4 mg/kg intravenously, caused partial prevention of the reactions in 6 out of 10 responsive sheep. The cardiovascular and respiratory responses to ovine hydatid fluid may be due to antigen-antibody reactions or some toxic component of the fluid. Résumé. Effet du fluide hydatique ovin sur les systèmes cardio-vasculaire et respiratoire des moutons. La rupture du kyste hydatique chez l'homme provoque une réaction toxique d'une intensité modérée à très sévère, parfois même mortelle. La présente étude a pour but d'éta-(1) This investigation was supported by grants from the Iranian Ministry of Science, the Iran Foundation and the Pahlavie University.