Evaluation in white mice of the infectivity of eggs of Lagochilascaris minor (Nematoda: Ascarididae), incubated by decortication with sodium hypochlorite (NaOCl).

White mice were used to study the infectivity of the eggs of Lagochilascaris minor Leiper, 1909 after incubation in liquid media, with or without preservative substances. Potassium bichromate (K2Cr2O7) at 1% restrict hatching, while 1% formalin gave a greater larval yield. Incubation of eggs in distilled water, in Roux or Falcon flasks gave a good yield, whether the eggs were obtained from human feces or from experimentally infected cats. Treatment of eggs with Sodium hypochlorite (NaOCl) at 5.25% for 2 min prior to inoculation, produced a notable increment of the larval yield in the infections.

Experimental heteroxenous cycle of Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in white mice and in cats.

Reports of natural infections of sylvatic carnivores by adult worms of species similar to Lagochilascaris minor in the Neotropical region led to attempts to establish experimental cycles in laboratory mice and in cats. Also, larval development was seen in the skeletal muscle of an agouti (Dasyprocta leporina) infected per os with incubated eggs of the parasite obtained from a human case. In cats, adult worms develop and fertile eggs are expelled in the feces; in mice, larval stages of the parasite develop, and are encapsulate in the skeletal muscle, and in the adipose and subcutaneous connective tissue. From our observations, we conclude that the larva infective for the mouse is the early 3rd stage, while for the final host the infective form is the later 3rd stage. A single moult was seen in the mouse, giving rise to a small population of 4th stage larvae, long after the initial infection.

[Mansonelliasis in the southeast Venezuelan Orinoquia region]. / Mansonelosis en el area Sur-oriental de la Orinoquia Venezolana.

Physical exam and skin biopsy were performed and peripheral blood samples drawn from 10% of the inhabitants of 26 jungle villages of the State of Bolívar, Venezuela. One hundred and fifty three Indians and an inhabitant of mixed blood from 13 different communities were found to be infected with mansonelliasis representing a global index of 36.40% in the endemic area. The parasitosis was found to be concentrated in three areas. The largest, located in the southwest of the country and forming part of an extent infected area embarking neighboring parts of Venezuela and Brazil, contains villages with a parasite index of 80.76% and 94.44%. A second focus is located in the southeast, its carriers, as those of the first, are infected with Mansonella ozzardi. In a third, central eastern focus infections with Mansonella pertans were found. The patients infected with M. ozzardi were apparently asymptomatic and their physical exam was normal, even though individual parasite densities up to 30,000 microfilariae/ml blood and 22,000/gr skin were found.

[Natural infection of Speothos venaticus (Carnivora: Canidae) by adult stages of Lagochilascaris sp]. / Infección natural de Speothos venaticus (Carnivora: Canidae) por estadios adultos de Lagochilascaris sp.

An adult male Speothos venaticus Lund (bush dog) was found killed on a rural road in the Northeast of Bolívar State, in a locality where a patient with lagochilascariasis has lived for the past 16 years. The animal was frozen for 1 month, and after removal of the head and skin, was autopsied. Two adult gravid females of Lagochilascaris sp. were found in the trachea. Certain morphological characteristics of the soft parts differed from the description given for Lagochilascaris minor Leiper, 1909; however, stable characters, such as the form of the interlabials, the location of the vulva, and particularly the size and number of depressions of the egg shell appear to indicate that the worms are of the above mentioned species. Unfortunately, no males were found for study of the spicules and ejaculatory duct. In histological sections of the larynx and the trachea from the deep tissues, parts of degenerated worms were found, with characteristics attributable to Lagochilascaris sp.

[Infection induced in wild rodents Dasyprocta leporina (Rodentia: Dasyproctidae), with larval eggs of Lagochilascaris minor (Nematoda: Ascarididae)]. / Infección inducida en el roedor selvático Dasyprocta leporina (Rodentia: Dasyproctidae), con huevos larvados de Lagochilascaris minor (Nematoda: Ascarididae).

Specimens of Dasyprocta leporina (Linnaeus, 1758) were raised out their natural environment. At three to four months of age they were orally inoculated with Lagochilascaris minor (Leiper, 1909) eggs obtained from a native patient. The eggs were incubated for more than 80 days so that it was possible to obtain, by mechanical compression, larvae that could be maintained alive in liquid medium for 48 hours or more. The animals were sacrificed 14-46 days after infection and tangled larva in inflammatory nodules were found in skeletal muscle without foreign body reaction, abscess formation or calcification. The development of the nodules did not seem to affect the hosts. The larvae obtained were similar to those described by SPRENT as the third stage of these helminths. When white mice were inoculated with similar material it was not possible to recuperate larva from their tissues nor were nodules found. Based on these results it is postulated that the helminth does not present a pulmonary cycle and that its development requires an intermediary host.

Onchocerciasis endemic in the State of Bolivar, Venezuela.

Microfilariae of Onchocerca volvulus were demonstrated by single shoulder-skin biopsy in 42.8% of inhabitants of seven Amerindian villages in an area of approximately 10,000 km2, near the Brasilian Roraima Territory. The highest prevalence was found among the Yanomama Indians of Chajuraña (84.6%, with a mean of 61.3 microfilariae per mg of skin). The six other communities were affected, but with lower prevalence and microfilaria skin densities. The absence of lymphoedema and the few subcutaneous nodules and eye lesions found among the infected individuals suggest a relatively recent introduction of the disease to the region. Mansonella ozzardi infections were also detected in the area.

Lagochilascaris minor infection in Venezuela. Report of a case.

A Lagochilascaris minor infection in a 6-year-old Venezuelan girl with a 4-year history of nasal obstruction is reported. Treatment with levamisole resulted in clinical and radiological cure. Eggs of L. minor were observed in the patient's feces; these were cultured to second stage larvae.

Microfilaria bolivarensis: a new species of filaria from man in Venezuela.

An unsheathed microfilaria, unlike any other already described from man, was found in thick blood smears and Knott samples taken from Amerinds living along the upper Caura River in Bolivar State, Venezuela. The mirofilaria, which measures 256 x 7-8 micrometers in thick blood smears and 300 x 8 micrometers in Knott samples, is easily differentiated morphologically from Mansonella ozzardi with which it often occurs concomitantly. It is readily differentiated, on morphological criteria, from all other species of filariae which infect man, as well. The parasite has been named Microfilaria bolivarensis after the geographical locality in which it was discovered.