David G. Young

Dispersal of phlebotomine sand flies (Diptera: Psychodidae) in a colombian focus of leishmania (Viannia) brasiliensis

Dispersal of five species of phlebotomine sand flies was studied in a coffee plantation near Arboledas, Colombia, by mark-release-recapture studies using fluorescent powders. The estimated recapture rate for males of Lutzomyia shannoni marked and released during the day was 28.1%, significantly higher than that for all other species (p < 0.05). Recapture rate of female Lu. shannoni was 9.5%, and no females of the other four species were recovered. This suggests either that Lu. shannoni is a more sedentary species than the others, or that the large trees on which these insects were captured and recaptured function as foci of lekking behaviour in males. The high recapture rates of females of this species may indicate that oviposition occurs in close proximity to the bases of these trees. Although most marked sand flies were recaptured within 200 m of their release point, a single female Lu. gomezi was recovered 960 m away 36 h after release. This suggests that the dispersal capacity of Lutzomyia species may be greater than has been thought, an important consideration in future control programs directed against these insects in Leishmania-endemic areas.

Ecology of phlebotomine sand flies (Diptera: Psychodidae)in a focus of Leishmania (Viannia) brasiliensis in northeastern Colombia

The phlebotomine sand fly fauna of two coffee plantations in a Leishmania-endemic area of Norte de Santander, Colombia was studied. Regular insect collections using a variety of methods were made for three and a half years. Information was obtained on diurnal resting sites, host range and seasonal abundance for 17 species, of which five (Lutzomyia spinicrassa, Lu. serrana, Lu. shannoni, Lu. ovallesi and Lu. gomezi) were far more numerous than the others, anthropophilic and present throughout the year. The behaviour of these and the remaining 12 species is discussed in relation to their potential role in transmission of Leishmania (Viannia) braziliensis in the area.

New World Vectors of the Leishmaniases

The leishmaniases are a group of enzootic and zoonotic diseases caused by morphologically similar parasites in the genus Leishmania (Protozoa: Trypanosomatidae). Mammal reservoirs, of which there are many species (76), may or may not show signs of infection (24, 52, 71). Furthermore, some of the leishmanial species are host-specific and have not been reported in humans (e.g., Le. hertigi of porcupines). Those species that infect man cause an estimated 400,000 new cases each year throughout the world (178). Clinical symptoms of cutaneous, mucocutaneous, and visceral disease in man vary considerably, depending on the species of Leishmania, immunological responses of the individual, and other factors (178). Putative vectors of these diseases are sand flies in the genera Lutzomyia (New World) and Phlebotomus (Old World), but incrimination of specific vectors and mammal reservoirs remains undetermined in many foci (66).

First isolation of Trypanosoma cruzi from a wild-caught Triatoma sanguisuga (LeConte) (Hemiptera: Triatominae) in Florida, U.S.A.

An adult female Triatoma sanguisuga was found to be naturally infected with Trypanosoma cruzi. This is the first report of a T. cruzi infection in this bug in Florida and suggests that a study of trypanosomiasis in reservoirs and vectors in north Florida is warranted.

Additional Plasmodium species from Anolis lizards of Hispaniola and Panama

Saurian malaria parasites in the Caribbean were previously represented by only two species, Plasmodium azurophilum and P. floridense. An additional three species of Plasmodium occur on Hispaniola which appear, because of morphometric and qualitative similarities, to be related to South and Middle American species: a subspecies of Plasmodium tropiduri in Anolis cybotes; a population of Plasmodium minasense anolisi in A. cybotes and A. distichus; and another parasite in A. distichus which is designated as a subspecies of a previously undescribed Plasmodium species in Anolis limifrons. Taxonomic descriptions based upon morphology of mature schizonts and gametocytes are given, the previously unknown parasites are described as new species/subspecies, and comparison is made with P. floridense which also occurs in their respective host species. A Fallisia species was also present but is not described. The increased diversity of Plasmodium parasites in Hispaniolan anoles is attributed to colonization of the island by four separate evolutionary lines of Anolis lizards, in comparison to fewer invasions of Jamaica and Puerto Rico, where only P. floridense and P. azurophilum are found.

The microps group of Lutzomyia França with descriptions of two new species from South America (Diptera: Psychodidae: Phlebotominae)

Six species of phlebotomine sand flies in the genus Lutzomyia Franca from South America are included in the newly-created species group microps. References and illustrations of the species are given, including descriptions of two new forms - L. nematoducta n.sp., male and female from northern Brazil, and l. preclara n.sp. male from Colombia and Peru. The males in the species group microps are keyed.

Sporogony, development and ultrastructure of extrinsic stages of Plasmodium mexicanum

Abstract Klein T. A. , Akin D. C. , Young D. G. , Telford S. R. , Jr. and Butler J. F. 1988. Sporogony, development and ultrastructure of extrinsic stages of Plasmodium mexicanum. International Journal for Parasitology 18 : 463–476. The sporogonic stages of Plasmodium mexicanum in the midgut and salivary glands of Lutwmyia vexalor were studied by light and electron microscopy. The sporogonic cycle of P. mexicanum maintained at 27 °C was completed by 6.5 days after an infective bloodmeal. Sporozoites were relatively short (4–6 μm) when compared to most other Plasmodium sporozoites. The nucleus, with a distinct nucleolus, was relatively large in the early non-vacuolated oocyst. Oocyst differentiation was initiated by the formation of subcapsular spaces and internal vacuolization which eventually coalesced and formed cytoplasmic clefts (sporoblastoids). Sporozoite formation was initiated early in the differentiated oocyst by the formation of a pair of convex electron dense membranes. A moderately electron dense inclusion body. a nucleus, and a single spherical mitochondrian were observed migrating into the evaginating sporozoite. Rhoptries and micronemes appeared to arise de novo from the moderately dense inclusion bodies which degenerated and were not observed in mature Sporozoites. After their release from oocysts, Sporozoites appeared in the salivary glands of L. vexator . Sporozoites were constricted at the parasite-host cell junction during entry into the salivary gland and were enclosed within a parasitophorous vacuole formed by the host cell membrane after entering the salivary gland cell. Sporozoites became extracellular as they continued to migrate into the lumen of the salivary gland, in similar manner to that seen when entering the salivary gland cell. The arrangement of the subpellicular microtubules (asymmetrically, with 2 3 of the microtubules occupying 1 2 of the sporozoite circumference, and 1 3 in the remaining half) was different from that observed in mammalian malarias, where all but one microtubule lie in two-thirds of the sporozoite circumference, but was similar to Plasmodium agamae , a saurian malaria. Except for the arrangement of the subpellicular microtubules, the structure and arrangement of organelles was similar to that observed for other Plasmodium species.

Lutzomyia Cirrita N. SP. from Colombia with a New Synonym in the Genus (Diptera: Psychodidae: Phlebotominae)

The male and female of Lutzomyia cirrita n. sp. are described and illustrated from specimens collected in Antioquia Dep., Colombia. It was usually taken in human biting collections and is related to L. peruensis (Shann.). L. montoyai (Sherlock) is a junior synonym of L. osornoi (Rist. and Van Ty) another Colombian sand fly closely related to L. cirrita (NEW SYNONYMY).

Ultrastructure of sporozoites of Schellackia golvani (Eimeriorina: Lankesterellidae) in the green anole, Anolis carolinensis

Abstract In the lizard host, Schellackia golvani sporozoites were observed in parasitophorous vacuoles of the polymorphonuclear series of leukocytes. Surr parasitophorous vacuole are numerous vesicles, intravascular tubules and electron-dense granules. The parasite envelope consists of a double membrane. A cytostome (micropyle), a conoid and apical rings are present. Paralamellate bodies, mitochondria, nucleus, nucleolus, rhopteries, micronemes and a single non-membrane-bound electron-lucid body were identified. The sporozoite subcellular morphology of S. golvani is similar to other sporozoan species belonging to the genera of Schellackia, Haemogregarina, Lankesterella, Eimeria and Toxoplasma .

The male of the sandfly Sergentomyia blossi (Kirk and Lewis) from Kenya (Diptera: Psychodidae: Phlebotominae)

The previously unknown male of Sergentomyia blossi (Kirk and Lewis) is described and illustrated. It differs from S. yusafi (Sinton) and S. ruttledgei (Lewis and Kirk) mainly in details of the cibarial armature. Further information on the structure of the S. blossi female is given. Specimens were collected in rock crevices near Rabai, Kenya.