Fertilizer policy in the developing countries: the case of Brazil

This paper deals initially with the role of mineral fertilizers in increasing agricultural production: the relationship between the two variables is illustrated within global, regional national and local contexts. The pattern and trends in fertilizer usage in Brazil are presented next, namely: increase in consumption in the period 1950/72; regional distribution; consumption as related to crops and cultivated land. It is shown that in less than a quarter or century fertilizer use has increased in the country nearly 12 fold, whereas world consumption was raised 7 fold, thus exceeding estimates based in several criteria. Steps taken to secure the raise in fertilizer consumption above the historical trend are discussed: research experience for outlining fertilization recomendations; the transfer of the knowledge to the farmer by the extension work both official and private; the credit policy and special incentives for the purchase of fertilizer; the national policy for minumum proces of agricultural products; the implantation of a national fertilizer industry. It is considered that the Brazilian experience adapted to similar local conditions in other developing countries, presents a possibility for achieving beneficial results without inflationary reflexes in the economy.

Studies on the relationship between lectin binding carbohydrates and different strains of Leishmania from the New World

The culture forms of L. mexicana pifanoi (LRC L-90), L. mexicana mexicana (LRC L-94, M-379); L. braziliensis braziliensis (LRC L-77, L-1, M-2903, H-LSS) and L. mexicana amazonensis (H-JMMO, M-JOF, H-21, H-PLL,M-1696) were tested with the following lectins: Canavalia ensiformis, Ricinus communis-120, Axinella polypoides, Phaseolus vulgaris, Evonymus europaeus, lotus tetragonolobus, Dolichos biflorus, Aaptos papillata II, Laburnum alpinum, Ulex europaeus, Arachis hypogaea and Soja hispida. All examined strains of Leishmania were agglutinated by C. ensiformis, R. communis-120 and A. popypoides. No agglutination reactions were observed with P. vulgaris, D.biflorus, A. papillata II, E. europaeus and L. tetragonolobus. Only L. m. pifanoi and the L. m. amazonensis strains H-JMMO and MJOF showed agglutination reactions with S. hispida, U. europaeus, L. alpinum and A. hypogaea, while L. m. mexicana (LRC L-94; M-379) strains, L. b. braziliensis H. LSS, LRC L-77; L-1; M-2903 and the L. m. amazonensis strains, H-PLL, H-21, M-1696 showed no agglutination reactions with these four lectins.

Indirect immunofluorescence test in new world Leishmaniasis: serological and clinical relation-ship

The indirect immunofluorescence test (IF) for anti-Leishmania antibodies (IgC and IgM) was performed with sera form the following groups of individuals: 214 cutaneous leishmaniasis patients, 28 healthy subjects with positive Montenegro's skin test (MST), 29 healthy subjects with negativeMST and 16 visceral leishmaniasis patients. The first four groups came from a suburban area of Rio de Janeiro (Jacarepaguá) where cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis is endemic. It was observed that IF-IgM titers were significantly higher amongst the cutaneous leishmaniasis patients with less than four months of disease as compared to those with longer periods and that IF-IgG titers were significantly higher in patients with multiple lesions as compared to those with single lesions. The visceral leishmaniasis patients had IF-IgG titers significantly higher than those from cutaneous leishmaniasis patients. A group of 28 individuals selected amongst the 214 cutaneous leishmaniasis patients had their IF-titers (IgG and IgM) compared to those of the two control groups of healthy subjects from the endemic area, respectively with positive and negative MST. Significantly higher titers of IF-IgG and IF-IgM were found in the group with active disease. The same group of patients showed IF-IgG titers significantly lower at the end of the antimonial therapy than those observed during this tratment.

Monoclonal antibodies for the identification of New World Leishmania species

Monoclonal antibodies specific for selected species complexes of Leishmania have been employed for the characterization of several representative strains of Leishmania isolated from different hosts and localities in the Americas. In the past 15 years, data have been accumulated concerning (i) the specificities of a number of these monoclonal antibodies and (ii) the antigenic variation (level of the expressed antigenic determinants) occurring among New World Leishmania species or strain variants as recognized by the monoclonal antibodies. This report is an attempt to summarize in brief the data accumulated to date on these points and to indicate the directions for future applications of these specific monoclonal antibodies for identification of leishmanial isolates.

Genetic Diversity in Natural Populations of New World Leishmania

Our results have shown the wide diversity of parasites within New World Leishmania. Biochemical and molecular characterization of species within the genus has revealed that much of the population heterogeneity has a genetic basis. The source of genetic diversity among Leishmania appears to arise from predominantly asexual, clonal reproduction, although occasional bouts of sexual reproduction can not be ruled out. Genetic variation is extensive with some clones widely distributed and others seemingly unique and localized to a particular endemic focus. Epidemiological studies of leishmaniasis has been directed to the ecology and dynamics of transmission of Leishmania species/variants, particularly in localized areas. Future research using molecular techniques should aim to identify and follow Leishmania types in nature and correlate genetic typing with important clinical characteristics such as virulence, pathogenicity, drug resistance and antigenic variation. The epidemiological significance of such variation not only has important implications for the control of the leishmaniases, but would also help to elucidate the evolutionary biology of the causative agents.

Numerical Taxonomy of Old World Phlebotominae (Diptera: Psychodidae): 1. Considerations of Morphological Characters in the Genus Phlebotomus Rondani & Berté 1840

Numerical analyses (correspondence analysis, ascending hierarchical classification, cladistic approach) were applied to the morphological characters of the adults of the genus Phlebotomus Rondani & Berté 1840. They confirm the reliability of the classic classifications, and also redefine the taxonomic and phylogenetic position of certain taxa. Thus, Spelaeophlebotomus Theodor 1948, Idiophlebotomus Quate & Fairchild 1961 and Australophlebotomus Theodor 1948 deserve generic rank. Among the vectors of leishmaniasis, the subgenus Phlebotomus Rondani & Berté 1840 is probably ancient. The results attribute an intermediate taxonomic and phylogenetic position to the taxa Euphlebotomus Theodor 1948 and Anaphlebotomus Theodor 1948, and reveal the probable artificial nature of the latter. The comparatively large numbers of species of subgenera Paraphlebotomus Theodor 1948, Synphlebotomus Theodor 1948 and, above all, Larroussius Nitzulescu 1931 and Adlerius Nitzulescu 1931, suggest that they are relatively recent. The development of adult morphological characters, the validity of their use in taxonomy and proposals for further studies are discussed.

Numerical Taxonomy of Old World Phlebotominae (Diptera: Psychodidae): 2. Restatement of Classification upon Subgeneric Morphological Characters

Numerical analyses (correspondence analysis, ascending hierarchical classification, and cladistics) were done with morphological characters of adult phlebotomine sand flies. The resulting classification largely confirms that of classical taxonomy for supra-specific groups from the Old World, though the positions of some groups are adjusted. The taxa Spelaeophlebotomus Theodor 1948, Idiophlebotomus Quate & Fairchild 1961, Australophlebotomus Theodor 1948 and Chinius Leng 1987 are notably distinct from other Old World groups, particularly from the genus Phlebotomus Rondani & Berté 1840. Spelaeomyia Theodor 1948 and, in particular, Parvidens Theodor & Mesghali 1964 are clearly separate from Sergentomyia França & Parrot 1920.

Correlation of male genital filaments and female spermathecal ducts in New World sand flies of the Lutzomyia intermedia species complex (Diptera: Psychodidae, Phlebotominae)

The lengths of the male genital filaments and female spermathecal ducts were measured in phlebotomine sand flies of the Lutzomyia intermedia species complex and the ratios between these characters calculated. Ratios for L. intermedia s. s. from Northeast vs Southeast Brazil (Espírito Santo and Minas Gerais), Espírito Santo/Minas Gerais vs Rio de Janeiro/São Paulo and L. intermedia vs L. neivai were significantly different at P < 0.1, 0.05 and 0.01 respectively when compared using ANOVA. The spermathecal ducts and genital filaments of L. intermedia were significantly longer than those of L. neivai (P < 0.01) and could be used to differentiate these species. The taxonomic and biological significance of these differences is discussed.