Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean
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Amazon Malaria Initiative/ Amazon Network for the Surveillance of Antimalarial Drug Resistance Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean INICIATIVA AMAZÓNICA CONTRA LA MALARIA/ RED AMAZÓNICA DE VIGILANCIA DE LA RESISTENCIA A LOS ANTIMALÁRICOS Documento estratégico para la gestión del suministro y garantía de la calidad de los medicamentos e insumos para el diagnóstico y tratamiento de la malaria Recommended Citation: US Centers for Disease Control and Prevention (CDC), Pan American Health Organization (PAHO/WHO), and RTI. 2011. Strategic Orientation Document for Malaria Vector Surveillance and Control in La tin America and the Caribbean. Submitted to the U.S. Agency for International Development by the CDC and Links Media, LLC. Gaithersburg, MD. Available at http://www.usaidami.org/resources.shtml Amazon Malaria Initiative/ Amazon Network for the Surveillance of Antimalarial Drug Resistance TABLE OF CONTENTS 1. Glossary / 5 2. Acronyms and abbreviations / 6 3. Objective / 7 4. Introduction / 9 5. Vector control / 11 5.1 Indoor residual spraying / 12 5.2 Insecticide-treated nets / 13 5.3 Source reduction / 14 5.4 Integrated vector management / 15 6. Vector surveillance / 17 6.1 Entomological surveillance / 18 6.2 Monitoring vector control operations / 22 6.3 Entomological indicators / 23 6.4 Operational indicators / 25 7. Monitoring plans per epidemiological strata / 29 7.1 Moderate to low-transmission settings / 29 7.2 Low to very low-transmission settings / 31 7.3 Settings with no active transmission but risk of transmission / 33 8. References / 35 9. Annexes / 39 Annex 1: Malaria vectors in the Americas / 39 Annex 2: WHO recommended insecticides for indoor residual spraying / 40 Annex 3: WHO recommended long-lasting insecticide-treated nets / 41 Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean 3 About this document: This document was produced through the Amazon Malaria Initiative (AMI) and was financed by the U.S. Agency for International Development (USAID). Photo Credits/Cover Top: © 2008 David Parsons Lower left: © 2005 James Gathany/CDC Lower right: © 2008 David Spitz/PAHO/WHO Disclaimer: The author’s views expressed in this publication do not necessarily reflect the views or positions of the U.S. Agency for International Development or the U.S. Government. August 2011. 2 Amazon Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance 1 Glossary Anthropophagic: when vectors feed preferentially on humans Entomological inoculation rate (EIR): the number of bites from an infectious mosquito experienced by an individual per unit of time Endophagic: when vectors preferentially feed indoors Endophilic: when vectors preferentially rest indoors Exophagic: when vectors preferentially feed outdoors Exophilic: when vectors preferentially rest outdoors Gonotrophic cycle: the egg production cycle in female mosquitoes, which includes blood meal digestion, egg maturation, and oviposition Monitoring: systematic tracking of program actions over time Primary vector: an arthropod that transmits a pathogen or parasite from one vertebrate host to another and that is able to sustain the organism in its natural cycle Secondary vector: an arthropod that transmits a pathogen or parasite from one vertebrate host to another but that cannot sustain the organism in a natural cycle without transmission by a primary vector Species complex: a group of species that is reproductively isolated from each other but with very similar morphology Surveillance: the ongoing systematic collection, analysis, and interpretation of data and the dissemination of data to those who need to know in order for action to be taken Synergists: inhibitors of detoxification enzymes, such as esterases, oxidases and glutathione S-transferases, that are important in the metabolism of insecticides Sympatric: populations with an overlapping distribution or that coexist Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean 5 2 ACRONYMS AND ABBREVIATIONS AMI Amazon Malaria Initiative API Annual parasite index CDC U.S. Centers for Disease Control and Prevention DDT Dichlorodiphenyltrichloroethane HBI Human blood index HLC Human landing catches IRS Indoor residual spraying ITNs Insecticide-treated nets IVCC Innovative Vector Control Consortium IVM Integrated vector management LLINs Long-lasting insecticide-treated nets NMCP National Malaria Control Program PAHO Pan American Health Organization PSC Pyrethrum spray catches RBM Roll Back Malaria Partnership SR Source reduction USAID United States Agency for International Development WHO World Health Organization WHOPES WHO Pesticide Evaluation Scheme 4 Amazon Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance 3 Objective The purpose of this document is to serve as a strategic guide to address malaria vector surveil- lance and control in the Americas, where malaria transmission is characterized as moderate to low. This document summarizes the discussions and recommendations of the Amazon Malaria Initiative (AMI) technical advisory group and aims to promote strategies that are evidence-based. It is intend- ed that this document will be updated regularly to incorporate new developments, findings, input, and suggestions from partners, as well as those arising from its own implementation. Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean 7 6 Amazon Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance 4 Introduction Since documenting the interruption of malaria transmission in several countries in the 1960s, 23 coun- tries in the Americas still have endemic malaria transmission: Argentina, Bahamas, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, Guatemala, Guyana, French Guiana, Haiti, Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Dominican Republic, Suriname and Venezuela (PAHO 2010). The region reported 524,123 laboratory-confirmed malaria cases in 2009 (representing a 56% re- duction in malaria morbidity in the region as compared with 2000) and 109 deaths in 2009 (a 70% decrease relative to the 2000 baseline figures). Seventy-four percent of infections were caused by Plas- modium vivax, 26% by Plasmodium falciparum, and less than 0.1% by Plasmodium malariae (locally reported in Brazil, French Guiana, Guyana, Suriname, and Venezuela) (PAHO 2010). Recent trends suggest that some countries, such as Argentina, El Salvador, Mexico, and Paraguay, will likely continue to advance toward elimination of the disease in coming years. The transmission dynamics of malaria in the Americas comprises a complex epidemiological scenario: both P. falciparum and P. vivax parasites are sympatric in the human host and in the vector population. There is wide diversity of anopheline species that are competent vectors that coexist with a temporal succession favoring sustained transmission. As a result, patterns and intensity of malaria transmission can be remarkably diverse, requiring a variety of approaches for entomological surveillance and vector control. Entomological surveillance is a cornerstone of effective and sustained malaria control. However, the best developed malaria vector surveillance indicators and techniques are mainly applicable to areas with high malaria transmission and, in the Americas transmission levels very seldom fall within this category. Malaria endemic areas of the Americas are generally considered moderate to low transmis- sion settings. The inadequacy of traditional entomological surveillance strategies in these transmission .segnellahc elbaredisnoc htiw tem neeb evah meht tnemelpmi ot stroffe sa tnedive emoceb sah sgnittes sah emoceb tnedive sa stroffe ot tnemelpmi meht evah neeb tem htiw elbaredisnoc .segnellahc Malaria vector control programs rely on the indoor residual spraying (IRS) of insecticides and the distribution of insecticide-treated bed nets (ITNs) as primary vector control tools. However, there are significant knowledge gaps regarding their efficacy in the Americas, where different vector species vary substantially in host-seeking behaviors and respond differently to interventions. Thus, it is anticipated that a scale-up of these interventions might produce varying degrees of success, depending on local entomological and epidemiological contexts. Therefore, the use of regionally relevant entomological indicators to monitor impact will allow for vector control programs to monitor the effectiveness of these strategies and, where necessary, to seek alternatives. Strategic Orientation Document for Malaria Vector Surveillance and Control in Latin America and the Caribbean 9 8 Amazon Malaria Initiative/Amazon Network for the Surveillance of Antimalarial Drug Resistance 5 Vector control Interventions targeting malaria vectors are one of the most effective ways to prevent and reduce ma- laria transmission and are key technical elements of the World Health Organization's (WHO) Global Strategy for Malaria Control (WHO 1993). At present, vector control is one of the most impor- tant malaria control tools available, and may lower transmission to levels where elimination can be envisioned. Vector control through the application of residual insecticides was once the mainstay of malaria control in the Americas, and considerable reductions in malaria cases and