Brugia beaveri sp. n., from the lymph nodes, skin, and carcass of the raccoon (Procyon lotor) in Louisiana is described. This is the first Brugia species to be reported from mammals in North America. It differs from the six other described species of the genus generally in the smaller body size of the female, the size and structure of the spicules, and the larger microfilaria which has a distinctively long cephalic space. A sheathed microfilaria of the Brugia type was first discovered in the United States in 1953 in a thick blood film from a raccoon (Procyon lotor) from Lafitte, Louisiana (Beaver, personal communication). A similar microfilaria was found in the blood of a bobcat (Lynx rufus) in Florida in 1960 (Orihel, personal communication). In neither case was the adult worm recovered. In February 1963, sheathed microfilariae were again found in raccoons in Louisiana. The adult worm was subsequently recovered and is here described as a new species of the genus Brugia Buckley, 1960. It is the first species of this genus to be described from the United States, the second reported from the Western Hemisphere (Orihel, 1963). MATERIALS AND METHODS Seven raccoons were collected from an area near Rosedale, Louisiana, approximately 90 miles northwest of New Orleans. As six of the animals had been captured alive, their blood could be examined repeatedly before they were necropsied. Microfilariae in blood samples were fixed in 2% formalin. A dilute Azur II solution was added to formalin-fixed microfilariae to bring out morphologic details. Microfilariae were also studied in thick and thin blood films. Thick films were air dried, dehemoglobinized in 0.85% saline, fixed in hot (60 C) 70% alcohol, and stained with dilute Delafield's hematoxylin. Thin blood films were Received for publication 8 August 1963. * This study was supported in part by grants 2E-2 and AI-04919-01 from the National Institutes of Health, Public Health Service. fixed in methyl alcohol and stained 1 hr with Giemsa (2% in pH 7.0 buffered water). Adult worms were recovered by soaking the skin, carcass, and lymphatic tissues in warm 0.85% saline solution as described by Dunn (1931). In the examination of one raccoon in which seven worms were recovered the soaking fluid was, in addition, filtered through coarse filter paper; the material on the surface of the filter paper was then washed into a large petri dish and examined with a dissecting microscope. Adult worms were fixed in glacial acetic acid (Berland, 1961), transferred to 70% alcohol containing 5% glycerine, and then gradually brought into pure glycerine, the medium in which they were studied. All drawings were made with the aid of a camera lucida. Brugia beaveri sp. n. Brugia microfilariae were found in five of the seven raccoons examined. Microfilariae of a Dipetalonema sp. were found in six and those of Dirofilaria tenuis in all of the animals. Adult worms of the new Brugia species were recovered from only two. However, one of the seven raccoons was dead when brought into the laboratory and, although it had Brugia microfilariae in the blood, it was not examined for adult worms. From one raccoon a single male was recovered from the saline in which the skin had soaked. From the other, two complete males, a broken male, three complete females, and a broken female were recovered. One male was recovered from an axillary lymph node and another from a popliteal node; all other specimens were found in the saline in which the skin and carcass had been immersed.
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