Epidemiology and ecology of leishmaniasis in Latin-America

Some methods for the enzymic characterization of Latin-American Leishmania with particular reference to Leishmania mexicana amazonensis and subspecies of Leishmania hertigi

30 Brazilian stocks of Leishmania mexicana amazonensis and 13 stocks of subspecies of Leishmania hertigi were characterized by starch-gel electrophoresis, using 18 enzymes selected from a total of 36 investigated. L. m. amazonensis was separable from subspecies of L. hertigi by enzymic profiles of 11 enzymes. The L. m. amazonensis stocks, which were from a wide range of hosts in a large geographical area, were enzymically extremely homogeneous, and could only be subdivided on two enzymes; sub-groups did not relate to each other or to any differences in epidemiological characters, including the clinical form of the human disease. 12 stocks regarded as L. hertigi deanei, that were isolated from Coendou prehensilis prehensilis and Coendou sp. in Pará State, Brazil, were separable into two sub-groups by three enzymes. A single stock of L. hertigi hertigi from Panama was separable from both enzymic sub-groups of L. h. deanei, in each case by three enzymes. The significance of these and other characters of diversity is discussed, together with the use of enzymes for the identification of the leishmaniae.

Leishmania in phlebotomid sandflies. VII. On the taxonomic status of Leishmania peruviana, causative agent of Peruvian 'uta', as indicated by its development in the sandfly, Lutzomyia longipalpis

The name Leishmania peruviana was given by Velez (1913) to the parasite responsible for a form of cutaneous leishmaniasis known as 'uta'; this disease occurs in the Peruvian Andes. Clinical similarities between uta and 'oriental sore', which is caused by Leishmania tropica of the Eastern Hemisphere, have, however, led to the suggestion that uta is simply due to L. tropica, which was introduced into Latin America by African slaves or European immigrants. Leishmania species are divisible into three distinct sections, according to their pattern of development in their natural (phlebotomine) vectors. One of these sections, the PERIPYLARIA, contains the subspecies of Leishmania braziliensis, and is characterized by parasites that undergo a phase of development attached to the wall of the hindgut (pylorus and ileum), in addition to multiplication in the midgut and subsequent invasion of the foregut. Such development is unknown in any other group of leishmaniae, including those groups of the section SUPRAPYLARIA, which includes parasites of the L. tropica complex. Three isolates of L. peruviana were studied in laboratory-bred sandflies, Lutzomyia longipalpis (Lutz & Neiva), and all showed consistent and prolific development of rounded or stumpy flagellates attached to the wall of the hindgut and, in some instances, growth of free, elongate promastigotes throughout the midgut. Development of both L. tropica and L. major, in the same insect, was restricted to massive development of free flagellates in the midgut, up to the cardial valve. From the behaviour of L. peruviana in the sandfly, its slow growth in hamster skin and the small size of its amastigotes, it is concluded that this parasite is (a) distinctly different from both L. tropica and L. major, and (b) closely related to subspecies of L. braziliensis within the section PERIPYLARIA. On this evidence it is also concluded that L. peruviana is indigenous to the American continent. The specific name is best retained for the time being (rather than L. braziliensis peruviana).

Mobilizing Technology for Developing Countries

A new problem in technology policy-a discipline hitherto largely concerned with the modern industrial sector-is posed by the need for technology suited to creating productive jobs and providing minimum public services at a cost and level of sophistication within the reach of poor people in developing countries. Careful consideration must be given to overall and sectoral development objectives, economic and manpower resources, and the local institutional and sociocultural context. This may indicate the need for both hardware innovation, such as low-cost alternatives to waterborne sewerage, and social ("software") innovation, such as training large numbers of supervisors to implement improved technologies for labor-intensive civil works.