Anthropophilic Sand Flies Research Articles

Leishmaniasis in Colombia. I. Studies on the phlebotomine fauna associated with endemic foci in the Pacific Coast region.

Studies on the phlebotomine fauna related to the leishmaniasis endemic foci of the Colombian Pacific Coast were carried out in the municipalities of Tumaco and Buenaventura. In Inguapí del Guadual, Tumaco, Lutzomyia trapidoi and Lu. gomezi were the predominant anthropophilic species; Lu. panamensis and Lu. hartmanni were less frequent. In Bajo Calima, Buenaventura, Lu. trapidoi represented over 94% of the anthropophilic sandflies. Continuous sampling from 1800 to 0600 hours in Inguapí del Guadual demonstrated that Lu. trapidoi bites mainly at dusk and dawn whereas Lu. gomezi remains active throughout the night. In Inguapí del Guadual, promastigotes were found in 0.1% (2/2, 305) of Lu. trapidoi, 0.2% (3/140) of Lu. gomezi, and 0.2% (1/424) of Lu. panamensis samples collected. In Bajo Calima, 1.9% (8/429) of Lu. trapidoi were found to be infected. Leishmania braziliensis panamensis, the most common Leishmania subspecies in the human population of this endemic focus, was isolated from 1 Lu. trapidoi from Inguapí del Guadual. Parasitological and entomological findings suggest that Lu. trapidoi could be the main vector of Leishmania in these areas, although Lu. gomezi and Lu. panamensis were also predominant.

Experimental transmission of Leishmania mexicana to hamsters by bites of phlebotomine sand flies (Diptera: Psychodidae) from the United States.

Laboratory-reared Lutzomyia diabolica (Hall) and Lutzomyia shannoni (Dyar), the only known anthropophilic sand flies occurring in the United States, transmitted Leishmania mexicana Biagi by bite to Syrian hamsters. The parasite strain (MHOM/US/80/WR-411) was originally isolated from a human patient living in Uvalde, Tex. Eighty-eight percent of 523 L. diabolica and 95% of 173 L. shannoni became infected after feeding on leishmanial histiocytomas of experimentally infected hamsters. At least 6% of the L. diabolica and 12% of the L. shannoni refed on uninfected hamsters 3–14 d after the infecting blood meal. Five of 21 hamsters fed upon by one or more L. diabolica and five of five hamsters fed upon by L. shannoni developed cutaneous lesions 14–148 d after the transmitting bite(s).

Development of Leishmania mexicana in Lutzomyia diabolica and Lutzomyia shannoni (Diptera: Psychodidae).

Extrinsic development of Leishmania mexicana was observed in two anthropophilic sand flies, Lutzomyia diabolica (Hall) and Lu. shannoni (Dyar). First indication of development of ingested amastigotes appeared between 18 and 24 h postfeeding, when light to moderate infections of short, ovoid, slightly motile forms with short flagella were seen undergoing binary fission within the intraperitrophic space of the abdominal midgut. Later the parasites elongated and migrated forward, establishing a massive infection in the cardia, where broad, dividing forms were packed behind the stomodeal valve; many were attached to its cuticular surface by flagellar modifications called hemidesmosomes. Once this point in the life cycle of the parasite was reached, most promastigotes ceased dividing and became shorter and highly active. These metacyclic forms appeared first in the region of the cardia and stomodeal valve, then spread anteriorly to the pharynx, cibarium, and proboscis, as well as posteriorly to the midgut and hindgut.

The Phlebotomine Sand Fly Fauna (Diptera: Psychodidae) of Ecuador1

A checklist of phlebotomine sand flies of Ecuador (49 species and subspecies), with additional comments on some species, is given. The female of Lutzomyia abunaensis (species-group aragaoi), both sexes of L. (Trichophoromyia) napoensis, n. sp., L. (Trichophoromyia) wilkersoni, n. sp., and L. tortura, n. sp. (species-group vexator), are described. Three closely related and anthropophilic sand flies in the subgenus Psychodopygus (“L. davisi complex”) are keyed and illustrated.

Dermal factors which condition infection of Lutzomyia townsendi (Ortiz, 1959) by Leishmania spp. of Venezuela

Se estudia la susceptibilidad de Lutzomyia townsendi a la infección con Leishmania spp. sobre lesiones experimentales de hamsteres. Se estudia la frecuencia y distribución de los amastigotos en la dermis, relacionándola con la profundidad que alcanza el estilete bucal del insecto. Una correlación positiva, con significante coeficiente de correlación, se establece entre la frecuencia de los parásitos a una profundidad de 100-150 nm en la dermis y el éxito de la infección de los flebótomos.

Studies on infection rates of human-baited anthropophilic sandflies in Machakos District, Kenya

Investigation of sandfly vectors of visceral leishmaniasis (kala-azar) was intensified after the epidemic outbreak of the latter in Machakos District, Kenya, in the early 1970s. Studies were carried out to assess the infection rate of potential vectors using human baits during the height of the 1978 epidemic outbreak. The results presented here indicated that, in Machakos District, sandflies captured when coming to human baits had higher infection rates than those collected in the natural resting sites using suction tubes.

A pilot study to control phlebotomine sand flies (Diptera: Psychodidae) in a neotropical rain forest.

A pilot study was conducted to determine the feasibility of chemical control of phlebotomine sand flies in a highly complex Neotropical rain forest in Panama. The aim was to reduce the risk of contracting leishmaniasis within prescribed areas of the forest utilized by military troops for training or other special activities. The results indicate that an average 30% reduction of anthropophilic sand flies was achieved in 9 months by utilizing malathion as 2% EC spray or 95% ULV fogging applied bimonthly.

The biting rhythms of some anthropophilic phlebotomine sandflies in British Honduras.

(1966). The biting rhythms of some anthropophilic phlebotomine sandflies in British Honduras. Annals of Tropical Medicine & Parasitology: Vol. 60, No. 3, pp. 357-364.