Laboratory colonization and mass rearing of phlebotomine sand flies (Diptera, Psychodidae).

Laboratory colonies of phlebotomine sand flies are necessary for experimental study of their biology, behaviour and mutual relations with disease agents and for testing new methods of vector control. They are indispensable in genetic studies and controlled observations on the physiology and behaviour of sand flies, neglected subjects of high priority. Colonies are of particular value for screening insecticides. Colonized sand flies are used as live vector models in a diverse array of research projects, including xenodiagnosis, that are directed toward control of leishmaniasis and other sand fly-associated diseases. Historically, labour-intensive maintenance and low productivity have limited their usefulness for research, especially for species that do not adapt well to laboratory conditions. However, with growing interest in leishmaniasis research, rearing techniques have been developed and refined, and sand fly colonies have become more common, enabling many significant breakthroughs. Today, there are at least 90 colonies representing 21 distinct phlebotomine sand fly species in 35 laboratories in 18 countries worldwide. The materials and methods used by various sand fly workers differ, dictated by the availability of resources, cost or manpower constraints rather than choice. This paper is not intended as a comprehensive review but rather a discussion of methods and techniques most commonly used by researchers to initiate, establish and maintain sand fly colonies, with emphasis on the methods proven to be most effective for the species the authors have colonized. Topics discussed include collecting sand flies for colony stock, colony initiation, maintenance and mass-rearing procedures, and control of sand fly pathogens in colonies.

Multifarious characterization of leishmania tropica from a Judean desert focus, exposing intraspecific diversity and incriminating phlebotomus sergenti as its vector.

The predominant sand fly species collected inside houses in Kfar Adumim, an Israeli village in the Judean Desert that is a focus of cutaneous leishmaniasis, was Phlebotomus papatasi, which was also caught attempting to bite humans. Phlebotomus sergenti, which is rarely seen inside houses, constituted the predominant sand fly species in caves near the village. Leishmania isolates from Ph. sergenti and humans typed as Leishmania tropica. Sand fly and human isolates produced similar small nodular cutaneous lesions in hamsters. Isolates produced excreted factor (EF) of subserotypes A(9) or A(9)B(2), characteristic of L. tropica and reacted with L. tropica-specific monoclonal antibodies. Isoenzyme analysis consigned the strains to the L. tropica zymodemes MON-137 and MON-275. Molecular genetic analyses confirmed the strains were L. tropica and intraspecific microheterogeneity was observed. Genomic fingerprinting using a mini-satellite probe separated the L. tropica strains into two clusters that were not entirely congruent with geographic distribution. These results support the heterogeneous nature of L. tropica and incriminate Ph. sergenti as its vector in this Judean Desert focus.

Detection of amastigote-like forms in the valve of Phlebotomus papatasi infected with Leishmania major.

A massive and homogeneous amount of amastigote-like forms was detected in the stomodeal valve (SV) and the thoracic mid-gut (TMG) of Leishmania major-infected Phlebotomus papatasi, which received a second blood meal 13 to 21 days post-infection on healthy anaesthetized hamsters. After re-feeding, the infected sand flies were dissected out to examine the morphology of the parasite in SV, TMG and the abdominal mid-gut (AMG). Different promastigote forms were seen in the infected flies. Among these included typical promastigotes (nectomonads and haptomonads), paramastigotes, metacyclic promastigotes and, in some samples, the here-reported amastigote-like forms. The Leishmania amastigote-like forms were detected in the SV of sand flies with 14, 18 and 21 days of infection as well as in the TMG at 13 and 18 days post-infection. However, the amastigote-like forms were not detected in the AMG. Factors such as the acidic pH predominating the TMG and the SV, as well as the temperature of the ingested blood, among others, are suggested as contributing to the transformation of the typical promastigotes into the amastigote-like forms. The significance of this finding is discussed and the possible biological advantage for transmission of Leishmania is considered.

Detection of amastigote-like forms in the valve of Phlebotomus papatasi infected with Leishmania major

A massive and homogeneous amount of amastigote-like forms was detected in the stomodeal valve (SV) and the thoracic mid-gut (TMG) of Leishmania major-infected Phlebotomus papatasi, which received a second blood meal 13 to 21 days post-infection on healthy anaesthetized hamsters. After re-feeding, the infected sand flies were dissected out to examine the morphology of the parasite in SV, TMG and the abdominal mid-gut (AMG). Different promastigote forms were seen in the infected flies. Among these included typical promastigotes (nectomonads and haptomonads), paramastigotes, metacyclic promastigotes and, in some samples, the here-reported amastigote-like forms. The Leishmania amastigote-like forms were detected in the SV of sand flies with 14, 18 and 21 days of infection as well as in the TMG at 13 and 18 days post-infection. However, the amastigote-like forms were not detected in the AMG. Factors such as the acidic pH predominating the TMG and the SV, as well as the temperature of the ingested blood, among others, are suggested as contributing to the transformation of the typical promastigotes into the amastigote-like forms. The significance of this finding is discussed and the possible biological advantage for transmission of Leishmania is considered

A new filaria of a lizard transmitted by sandflies

A description is given of Madathamugadia wanjii n. sp., a Splendidofilariinae parasite of the gecko Ptyodactylus hasselquistii, on the west bank of the River Jordan and of its life cycle in Phlebotomus duboscqi. The new species is close to M. ivaschkini (Annaev, 1976) n. comb., of Turkmenistan, wich is also transmitted by sandflies (Reznik, 1982). The genus Madathamugadia is now comprised of four species, two from Madagascar and two from the Mediterranean sub-region; it differs from the genus Thamugadia by the presence of a double row of papillae anterior to the cloaca of the male. The larval characters of Splendidofilarinae of lizards confirm the affinity of these parasites to the Splendidofilarinae of birds (Chandlerella and Splendidofilaria); the first group could have arisen from the second by "captures" wich could have occurred in several places