cmdtla.org - Saúde Tropical

PI: JOÃO PINTO Population genetics and Bio-ecology (PI: João Pinto) The origins and evolution of the malaria vector Anopheles gambiae are being studied in the islands of Bioko, Príncipe, São Tomé and Annobón, located in the Gulf of Guinea. A multi-gene approach comprising microsatellite genotyping and DNA sequencing (mtDNA and ITS-rDNA) is being used to establish the number of colonisation events of this mosquito into the islands. Genetic data is being combined with historical records of human population migration events in order to determine the importance of man-mediated mosquito dispersal.

Publicações  e Comunicações [referências]

Scientific articles:

Pinto J., Lynd A., Vicente J.L., Santolamazza F., Randle N.P., Gentile G., Moreno M., Simard F., Charlwood J.D., do Rosário V.E., Caccone A., della Torre A. &. Donnelly M.J. (2007). Multiple origins of knockdown resistance mutations in the Afrotropical mosquito vector Anopheles gambiae. PloS ONE 11: e1243. (IF: n.a.).

Moreno M., Salgueiro P., Vicente J.L., Cano J., Berzosa P.J., de Lucio A., Simard F., Caccone A., do Rosario V.E., Pinto J. & Benito A. (2007). Genetic population structure of Anopheles gambiae in Equatorial Guinea. Malaria Journal 6: 137 (IF: 2.75).

Communications:

Pinto J., Marshal J.C., Vicente J.L., Salgueiro P., Yawson A., Santolamazza F., Donnelly M.J., Moreno M., Simard F., do Rosário V.E., della Torre A. & Caccone A. (2007). Origins and gene flow among Anopheles gambiae populations on islands of the Gulf of Guinea, West Africa. Third International Meeting on "Molecular and Population Biology of Mosquitoes and Other Disease Vectors". Kolymbari, Crete, Greece. Oral communication.

Vicente J.L., Salgueiro P., Arez A.P., Cravo P.V.L., Ferreira C., do Rosário V.E. & Pinto J. (2007). Genetic characterisation of Plasmodium falciparum populations in São Tomé and Príncipe islands, West Africa. 5th European Congress on Tropical Medicine and International Health. Amsterdam, The Netherlands. Tropical Medicine and International Health 12, S1 (O26-34, p. 78). Oral communication.

Pinto J., Marshal J.C., Vicente J.L., Salgueiro P., Yawson A., Santolamazza F., Donnelly M.J., Moreno M., Simard F., della Torre A., do Rosário V.E. & Caccone A. (2007). Origem, evolução e fluxo genético do vector da malária Anopheles gambiae. XLIII Congresso da Sociedade Brasileira de Medicina Tropical. Campos do Jordão SP, Brasil. Revista da Sociedade Brasileira de Medicina Tropical 70 Suppl. I (MA071, p. 158). Invited lecture.

Kanganje Y., Sousa C.A., Charlwood J.D., do Rosário V.E., Fortes F. & Pinto J. (2007). Resistência a insecticidas em vectores da malária em Angola . XLIII Congresso da Sociedade Brasileira de Medicina Tropical. Campos do Jordão SP, Brasil. Revista da Sociedade Brasileira de Medicina Tropical 70 Suppl. I (MA072, p. 158). Poster.

Bolsas aprovadas

Post-Doctoral Fellowship:. Patrícia Isabel Rosa Salgueiro. "Mating system and population structure of malaria vectors: ecological and genetic studies". Fundação para a Ciência e a Tecnologia (SFRH/BPD/34395/2006).

PhD "sandwich" Fellowship: Aline Fernandes Angella. "Population structure of Anopheles darlingi in Brasil". CAPES/GRICES.

Projectos aprovados/submetidos

Improving the sustainability of insecticide-based approaches to interrupt malaria transmission (IRITN). FP7-HEALTH-2007-B (2.3.2-9) - Pending

Support to integrated actions of UEI Malaria (PI: VE Rosário) with industry and SMEs

- Risk assessment of the impact of artificial lakes in the dynamics of mosquito vector populations. Consultancy for ecossistema, Lda. - Consultores em Engenharia do Ambiente. In collaboration with UEI Entomologia Médica (AP Almeida) and UEI Sistemas de Saúde (R Teodósio)

- Repellent effect of fabrics impregnated with DEET, permethrin and citronella by micro-encapsulation. TINAMAR- Indústrias Têxteis. In collaboration with and UEI Entomologia Médica (CA Sousa)

Linhas de investigação desenvolvidas [pequeno texto, ½ página por cada linha]

On-going Projects:

Malaria vectors in islands, studies on genetic isolation. UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) (OD/TS-05-00283).

The origins and evolution of the malaria vector Anopheles gambiae are being studied in the islands of Bioko, Príncipe, São Tomé and Annobón, located in the Gulf of Guinea. A multi-gene approach comprising microsatellite genotyping and DNA sequencing (mtDNA and ITS-rDNA) is being used to establish the number of colonisation events of this mosquito into the islands. Genetic data is being combined with historical records of human population migration events in order to determine the importance of man-mediated mosquito dispersal. The ultimate goals are to disentangle levels of contemporary versus historical gene flow and to access the degree of isolation of these island vector populations. This is a key issue for determining the suitability of islands as potential experimental sites for transgenic-based malaria control. This work involves the participation of a number of institutions from Europe, Africa and the USA.

Population structure and gene flow of malaria parasites on islands. FCT/MCTES, Portugal (POCI/SAU-ESP/56903/2004).

The main objective of this project is to combine genetic data obtained from analyses of neutral loci (microsatellites) and genes of interest (surface antigens and drug-resistance genes) as well as its surrounding regions, in order to access patterns of gene flow and selection pressures in P. falciparum populations of São Tomé and Príncipe islands. For the purpose, DNA isolates from different localities and time-points are being genotyped for linked and non-lined microsatellites, for the merozoite-surface genes msp1 and msp2 and drug-resistance genes pfcrt, dhfr and dhps.

Systematics and evolution of Culex pipiens from Portugal and Macaronesian islands. FCT/MCTES, Portugal (POCI/BIA-BDE/57650/2004).

This line of research focus in clarifying taxonomic and evolutionary relations among two behavioural forms (molestus and pipiens) of the mosquito vector Cx. pipiens. Bio-ecological and molecular studies are being carried out in order to characterise sympatric and allopatric populations from continental Portugal and Macaronesian islands. Entomological surveys have been conducted in Continental Portugal, Madeira and Cabo Verde islands. Culex pipiens field samples have been used in insectary experiments to determine autogeny and estenogamy. These samples are being analysed by morphometrics and microsatellite markers.

Other research lines:

Multiple origins of kdr genes in Anopheles gambiae.

A multi-centre joint-effort has been carried out to clarify the molecular evolution of knockdown resistance genes in the principal Afrotropical malaria vector Anopheles gambiae. Extensive sequencing analysis of the upstream intron-1 of the kdr gene was performed in samples collected from 15 countries of Sub-Saharan Africa. kdr alleles were widespread in West Africa and the co-occurrence of the two mutations L1014S and L1014F was detected in most West-Central localities surveyed. Intron-1 haplotype composition indicated that kdr alleles may have arisen from at least four independent mutation events. Neutrality tests provided evidence for a selective sweep acting on this genomic region, also in West Africa. This work involved collaborations between CMDT-LA and institutions from Europe, Africa and the USA.

Insecticide resistance and kdr mutations in Anopheles gambiae

Following field entomological surveys undertaken in four provinces of Angola (November 2006) aimed at characterising levels of insecticide resistance to DDT and pyrethroids, molecular analysis of the kdr locus was performed in A. gambiae phenotyped samples. Low levels of insecticide resistance were found in field populations of this malaria vector. Presence of kdr mutations was detected in samples from Cabinda and Luanda but no direct relation between these mutations and resistance phenotype was made. This work was undertaken in collaboration with the Programa Nacional de Controle da Malária/Ministry of Health of Angola (Dr. F. Fortes).

This research line was also developed in Equatorial Guinea (including Bioko island) through a collaboration with the Instituto Salud Carlos III, Madrid, Spain. Correlation between DDT/pyrethroid resistant phenotypes and kdr genotypes was also not evident by the analysis of two continental populations of A. gambiae.

Genetic structure of Glossina palpalis and HAT transmission in Equatorial Guinea.

This line of research aims at assessing the degree of genetic differentiation of G. palpalis populations between HAT foci of Equatorial Guinea (West Africa), using microsatellite analysis and mtDNA sequencing. The work involves a collaboration with the Instituto de Salud Carlos III  (Madrid, Spain) for the support of HAT control activities in Equatorial Guinea and with the LSTM (Liverpool, UK) for sequencing analysis.

Population structure of Anopheles darlingi in Brazil

Within the framework of a PhD project, the genetic structure of the neotropical malaria vector A. darlingi is being characterised by microsatellite DNA analysis. Genotyping procedures have been optimised for 8 microsatellite loci and these are being used to characterise genetic variability in A. darlingi samples from 10 collection sites of Brazil. Collaboration with Instituto de Biociências de Botucatu - IBB/UNESP, Brazil (Dr. P. Ribolla).

Formação avancada

M.Sc. Thesis

Yolanda Kanganje (Angola): "Knockdown insecticide resistance in Anopheles gambiae Giles, 1902 populations from Angola, Southern Africa". M.Sc. in Human Biology and Environment, Faculdade de Ciências, Universidade de Lisboa. Supervisor.

Graduation (B.Sc.) Thesis

André Galvão (Portugal): "Genetic structure of Plasmodium falciparum on the islands of São Tomé and Príncipe". Applied Chemistry (Biotechnology), Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa. Supervisor.

Érika Oliveira (Angola): "Genetic characterisation of the mosquito vector Anopheles gambiae in Bissau, Guiné-Bissau". Biology, Universidade Lusófona de Humanidades e Tecnologia. Supervisor.