Vector bionomics and malaria transmission in the Upper Orinoco River, Southern Venezuela.

A longitudinal epidemiological and entomological study was carried out in Ocamo, Upper Orinoco River, between January 1994 and February 1995 to understand the dynamics of malaria transmission in this area. Malaria transmission occurs throughout the year with a peak in June at the beginning of the rainy season. The Annual Parasite Index was 1,279 per 1,000 populations at risk. Plasmodium falciparum infections accounted for 64% of all infections, P. vivax for 28%, and P. malariae for 4%. Mixed P. falciparum/P. vivax infections were diagnosed in 15 people representing 4% of total cases. Children under 10 years accounted for 58% of the cases; the risk for malaria in this age group was 77% higher than for those in the greater than 50 years age group. Anopheles darlingi was the predominant anopheline species landing on humans indoors with a biting peak between midnight and dawn. A significant positive correlation was found between malaria monthly incidence and mean number of An. darlingi caught. There was not a significant relationship between mean number of An. darlingi and rainfall or between incidence and rainfall. A total of 7295 anophelines were assayed by ELISA for detection of Plasmodium circumsporozoite (CS) protein. Only An. darlingi (55) was positive for CS proteins of P. falciparum (0.42%), P. malariae (0.25%), and P. vivax-247 (0.1%). The overall estimated entomological inoculation rate was 129 positive bites/person/year. The present study was the first longitudinal entomological and epidemiological study conducted in this area and set up the basic ground for subsequent intervention with insecticide-treated nets.

[1]  A. Dalsgaard.  Editorial: Wastewater use – food safety and health aspects , 2007 .

[2]  Y. Rubio-Palis,et al.  Caracterization of anopheline malaria vector (Diptera: Culicidae) breeding sites at the upper Orinoco river, Amazonas, Venezuela , 2007 .

[3]  J. Lines,et al.  Community‐randomized trial of lambdacyhalothrin‐treated hammock nets for malaria control in Yanomami communities in the Amazon region of Venezuela , 2007, Tropical medicine & international health : TM & IH.

[4]  R. Harbach,et al.  Incrimination of Anopheles (Nyssorhynchus) rangeli and An. (Nys.) oswaldoi as natural vectors of Plasmodium vivax in Southern Colombia. , 2006, Memorias do Instituto Oswaldo Cruz.

[5]  C. Schlichting,et al.  The importance of Anopheles albitarsis E and An. darlingi in human malaria transmission in Boa Vista, state of Roraima, Brazil. , 2006, Memorias do Instituto Oswaldo Cruz.

[6]  Robert H Gilman,et al.  The effect of deforestation on the human-biting rate of Anopheles darlingi, the primary vector of Falciparum malaria in the Peruvian Amazon. , 2006, The American journal of tropical medicine and hygiene.

[7]  Yasmin Rubio-Palis,et al.  Caracterización de criaderos de anofelinos (Diptera: Culicidae) vectores de malaria del Alto Orinoco, Amazonas, Venezuela , 2005 .

[8]  Y. Rubio-Palis,et al.  Anopheles (Anopheles) neomaculipalpus: a new malaria vector in the Amazon basin? , 2005, Medical and veterinary entomology.

[9]  J. Grieco,et al.  COMPARATIVE SUSCEPTIBILITY OF THREE SPECIES OF ANOPHELES FROM BELIZE, CENTRAL AMERICA, TO PLASMODIUM FALCIPARUM (NF-54) , 2005, Journal of the American Mosquito Control Association.

[10]  Yasmin Rubio-Palis,et al.  Caracterización Ecoregional de los Vectores de Malaria en Venezuela , 2005 .

[11]  J. Coura,et al.  Cross-sectional study defines difference in malaria morbidity in two Yanomami communities on Amazonian boundary between Brazil and Venezuela. , 2004, Memorias do Instituto Oswaldo Cruz.

[12]  C. Flores-Mendoza,et al.  Natural Plasmodium Infections in Anopheles darlingi and Anopheles benarrochi (Diptera: Culicidae) from Eastern Peru , 2004, Journal of medical entomology.

[13]  M. Tada,et al.  Seasonal Malaria Transmission and Variation of Anopheline Density in Two Distinct Endemic Areas in Brazilian Amazônia , 2003, Journal of medical entomology.

[14]  A. AngelRosas,et al.  Comportamiento estacional del Anopheles (Nyssorhynchus) darlingi Root 1926 en localidades de Loreto y Madre de Dios, Perú. 1999-2000 , 2003 .

[15]  C. Chávez,et al.  Distribución geográfica y comportamiento estacional de la picadura del Anopheles (Nyssorhynchus) darlingi Root 1926 en localidades de la frontera Perú-Bolivia, Madre de Dios, Perú , 2003 .

[16]  M. Póvoa,et al.  Biting indices, host-seeking activity and natural infection rates of anopheline species in Boa Vista, Roraima, Brazil from 1996 to 1998. , 2002, Memorias do Instituto Oswaldo Cruz.

[17]  M. Póvoa,et al.  Malaria vectors in the municipality of Serra do Navio, State of Amapá, Amazon Region, Brazil. , 2001, Memorias do Instituto Oswaldo Cruz.

[18]  M. Póvoa,et al.  Distribution of Plasmodium vivax variants (VK210, VK247 and P. vivax-like) in three endemic areas of the Amazon region of Brazil and their correlation with chloroquine treatment. , 2000, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[19]  Y. Rubio-Palis,et al.  Larval habitats of anopheline mosquitoes in the Upper Orinoco, Venezuela. , 1999, Journal of vector ecology : journal of the Society for Vector Ecology.

[20]  C. Curtis,et al.  A comparison of use of a pyrethroid either for house spraying or for bednet treatment against malaria vectors , 1998, Tropical medicine & international health : TM & IH.

[21]  M S Rafael,et al.  Ecologic observations on anopheline vectors of malaria in the Brazilian Amazon. , 1998, The American journal of tropical medicine and hygiene.

[22]  Arnoldo Gabaldon,et al.  MINISTERIO DE SANIDAD Y ASISTENCIA SOCIAL ESCUELA DE MALARIOLOGIA Y SANEAMIENTO AMBIENTAL , 1998 .

[23]  Y. Rubio-Palis,et al.  Ecoregional classification of malaria vectors in the neotropics. , 1997, Journal of medical entomology.

[24]  L. Camargo,et al.  Hypoendemic malaria in Rondonia (Brazil, western Amazon region): seasonal variation and risk groups in an urban locality. , 1996, The American journal of tropical medicine and hygiene.

[25]  M. T. Marrelli,et al.  Anopheles oswaldoi a potential malaria vector in Acre, Brazil. , 1996, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[26]  Y. Rubio-Palis,et al.  Malaria entomological inoculation rates in western Venezuela. , 1992, Acta tropica.

[27]  P. Milligan,et al.  Cuticular hydrocarbons, isoenzymes and behavior of three populations of Anopheles darlingi from Brazil. , 1992, Journal of the American Mosquito Control Association.

[28]  T. Burkot,et al.  Development and evaluation of an enzyme-linked immunosorbent assay for Plasmodium vivax-VK247 sporozoites. , 1992, Journal of medical entomology.

[29]  K. Kain,et al.  Serologic and genetic characterization of Plasmodium vivax from whole blood-impregnated filter paper discs. , 1992, The American journal of tropical medicine and hygiene.

[30]  R. Zimmerman.  Ecology of malaria vectors in the Americas and future direction. , 1992, Memorias do Instituto Oswaldo Cruz.

[31]  E. Nardin,et al.  Sero-epidemiological studies of malaria in Indian tribes and monkeys of the Amazon Basin of Brazil. , 1989, The American journal of tropical medicine and hygiene.

[32]  R. Lourenço-de-Oliveira,et al.  Anopheline species, some of their habits and relation to malaria in endemic areas of Rondônia State, Amazon region of Brazil. , 1989, Memorias do Instituto Oswaldo Cruz.

[33]  J. Sattabongkot,et al.  Circumsporozoite protein heterogeneity in the human malaria parasite Plasmodium vivax. , 1989, Science.

[34]  L. Deane.  A cronologia da descoberta dos transmissores da malária na Amazônia brasileira , 1989 .

[35]  T. Burkot,et al.  Field evaluation of enzyme-linked immunosorbent assays for Plasmodium falciparum and Plasmodium vivax sporozoites in mosquitoes (Diptera: Culicidae) from Papua New Guinea. , 1987, Journal of medical entomology.

[36]  R. Nussenzweig,et al.  Potential vectors of malaria and their different susceptibility to Plasmodium falciparum and Plasmodium vivax in northern Brazil identified by immunoassay. , 1986, The American journal of tropical medicine and hygiene.

[37]  L. Deane.  Malaria vectors in Brazil , 1986 .

[38]  J. E. Hudson,et al.  Anopheles darlingi Root &Diptera: Culicidae& in the Suriname rain forest , 1984 .

[39]  K. Walls,et al.  A focus of hyperendemic Plasmodium malariae-P. vivax with no P. falciparum in a primitive population in the Peruvian Amazon jungle. , 1975, Bulletin of the World Health Organization.