Speciation and population structure in the morphospecies Lutzomyia longipalpis (Lutz & Neiva) as derived from the mitochondrial ND4 gene.

Recent studies have suggested that the phlebotomine sand fly Lutzomyia longipalpis (Diptera: Psychodidae), the principal vector of visceral leishmaniasis in the Neotropics, may consist of several allopatric sibling species. Phylogenetic and population genetic analyses of nucleotide variation in a 618-bp fragment of the mitochondrial ND4 gene were carried out on specimens of Lu. longipalpis from several locations in Central and South America. The analyses were concordant with previous findings, indicating that certain allopatric populations of Lu. longipalpis have become sufficiently differentiated as to represent sibling species. Phylogenetic analyses revealed deep genetic divisions between four clades represented by specimens from northern South America, Brazil, Central America, and an isolated Colombian population. Strong differentiation also was observed between certain populations within the first two clades. Partitioning of genetic diversity within and between Central American populations did not show the presence of more than one species in the region. However, distance, even within the 70-km range of the Honduran collection sites, was found to have a remarkably strong effect on gene flow. The highly subdivided population structure may be due to the patchiness of their distribution. F(ST) values comparing a Guatemalan population with several Honduran populations revealed a level of differentiation associated with a negligible rate of gene flow.

[Pediatric AIDS: characteristics of 17 Dominican cases]. / SIDA pediatrico: caracteristicas a proposito de 17 casos dominicanos.

PIP: During 1985 and December 1990 children referred to hospitals with HIV infection were subjected to a protocol previously established to determine HIV antibodies by ELISA and Western Blot methods. Children under 15 months of age underwent repeated tests to preclude the transfer of maternal antibodies. In this group only children with more than 6 months of follow-up were included. 17 cases were studied: 6 were children under 15 months of age, 8 were between 15 months and 5 years, and 3 were between 5 years and 15 years. 12 children originated from urban areas, 3 from rural areas, and 2 were foreigners. The clinical symptoms started in the first year of life in 8 cases, between 1 and 3 years in 7 cases, and after 5 years of age in 2 cases. HIV transmission was vertical in 8 cases, via blood transfusion in 2 cases, and in 7 cases the route of transmission could not be confirmed. The follow-up lasted 6 months for 5 cases; 18 months for 5 cases; 2 years for 4 cases; and 3.5 years for 3 cases. The clinical signs were predominantly: cutaneous lesions in 10 of the 17 cases, diarrheal disease in 7, fever in 6, malnutrition in 6, as well as hypertrophy, oral moniliasis, sepsis, esophageal candidiasis, otitis, and varicella in different patients. According to CDC classification, 9 cases corresponded to class P-1 (one of them with elevated immune function and the other with normal immune function); 6 corresponded to pediatric class P-2 (2 to subclass A, 2 to subclass D, and 2 to subclass D-2). 6 children died: 4 due to meningitis and sepsis, 1 due to varicella, and 1 due to malnutrition, sepsis, and esophageal candidiasis.^ieng