Echinococcus oligarthrus Cysts of Rabbits in Venezuela

Abstract

The life cycle of Echinococcus oligarthrus (Cestoda: Taeniidae) involves wild felids including the jaguar (Felis onca), puma (F. concolor) Geoffroy's cat (Schantz and Colli, 1973, J. Parasit. 59: 1138-1140), and wild cats (F. yagouaroundi) as definitive hosts, and the paca (Cuniculis paca), the agouti or Venezuelan picure (Dasyprocta sp.), the spiny rat (Proechimys sp.), and opossums (Didelphis marsupialis) as intermediate hosts (Thatcher, 1972, Ann. trop. Med. Parasit. 66: 99-105; D'Alessandro et al., 1981, Am. J. trop. Med. Hyg. 30: 1263-1276). Of the two neotropical species of Echinococcus that parasitize wild animals, E. oligarthrus and E. vogeli, the latter is also responsible for causing the polycystic hidatid disease (PHD) in humans in Colombia and neighboring countries (D'Alessandro et al., 1979, Am. J. trop. Med. Hyg. 28: 303317). Echinococcus vogeli is consequently a more important cestode, and has been widely studied. The larval stage of E. oligarthrus was not weli known until a differential study with the larval stage of E. vogeli was recently published (Rausch et al., 1978, Am. J. trop. Med. Hyg. 27: 11951202). This comparative study was based on the length of the rostellar hooks of protoscolices found in the cysts, a parameter considered as a suitable and reliable criteria for identifying larval stages of Echinococcus (Rausch et al., 1978, loc. cit.). We report 2 cases of E. oligarthrus cysts found in adult wild rabbits (Sylvilagusfloridanus) hunted in Lara State, in the West-central region of Venezuela. Case one: An adult male wild rabbit was