Unusual intestinal microvilli in the facultative parasitic nematode Halicephalobus gingivalis (Panagrolaimidae)

Halicephalobus gingivalis (Panagrolaimidae), formerly known as Micronema deletrix, is a free-living, bacteriophagous soil nematode which is also known to be a facultative parasite of horses and zebras. The first report of an infection of a horse with H. gingivalis dates from 1954. Since then, there have been approximately one hundred reports of an infection of which only two cases were not fatal. There are also three infections known in humans, fatal in all cases within 8 to 10 days after the first symptoms of disease. Little is known about the ultra structure of this nematode. Does it have all the characteristics of a free-living nematode or does H. gingivalis have specifications that are typical for parasitic species? We took a closer look at the ultra structure by means of transmission electron microscopy and found branched microvilli in the intestine. Furthermore, H. gingivalis seems to have all the characteristics of a free-living nematode