Search

A new filaria, Strianema venezuelensis gen. et sp. n., is described from armadillos in Venezuela. The adults inhabit the subcutaneous tissues and the microfilariae are found in the skin and occasionally the blood. The adults, which are of small size (males 9.6 to 13.8 mm in length by 57 to 63 microns in diameter, females 18.3 to 26.3 mm in length by 95 to 120 microns in diameter), have a distinctly striated cuticle. This filaria resembles most closely the genus Cercopithifilaria, from which it can be distinguished by the absence of a buccal capsule or pre-esophageal ring, and 11 to 13 pair of caudal papillae, three or four pair of which are separated as a group anterior to the cloaca. The species, S. venezuelensis, can be distinguished from the three other species of filariae described from armadillos by the undivided esophagus, number and distribution of caudal papillae in the male, size and shape of the spicules, and the distinctive microfilaria. The microfilaria, which averages 280 microns in length, has a unique, slender, almost filamentous tail.

A new species of Acanthocheilonema, Acanthocheilonema sabanicolae n. sp., is described from the subcutaneous tissues of the savanna armadillo (Dasypus sabanicola) in Venezuela. The adults (females 25-30.6 mm long by 61-78 micron wide; males 10.9-15.3 mm long by 42-44 micron wide) and the microfilariae (112-131 micron long by 3-5 micron wide) are the smallest within the genus. The microfilaria, a skin dweller, assumes a characteristic C-shaped curve, when fixed in 2% formalin, which serves to distinguish A. sabanicolae from others in the genus. Moreover, the spicules are notably smaller than any others in the Acanthocheilonema. Acanthocheilonema sabanicolae is the first species in this genus to be described from edentates, and, along with A. reconditum of dogs and A. pricei of opossums, is the third species of Acanthocheilonema to be reported from South America. Morphological features, vectors, and vertebrate hosts of the genus Acanthocheilonema are reviewed.

The histochemistry of armadillo skin has been studied. The dendritic cells are extremely large, very sharply outlined by methods for alkaline phosphatase and alpha-naphthyl-acetate esterase, and they are dopa-negative. The mastocytes, however, are dopa-oxidase-positive, probably due to peroxidase rather than tyrosinase activity. The giant cells of the granulomas normally seen in the dermis of the armadillo are strongly beta-glucuronidase-positive. These giant cells are evidently foreign body cells reacting to the crystals always present in the dermis of the armadillo. The centre of these crystals, which are cholesterol and fat-negative, is alkaline phosphatase-positive. Further study of the mastocytes and dendritic cells is necessary to elucidate their nature.