Training Manual On Malaria Entomology

Training Manual on Malaria EntomologyFor Entomology and Vector Control Technicians(Basic Level)September 2012This publication was produced for review by the United States Agency for InternationalDevelopment. It was prepared by RTI International.

Training Manual on Malaria EntomologyFor Entomology and Vector Control Technicians(Basic Level)Integrated Vector Management of Malaria and Other Infectious Diseases Task Order 2Contract GHA-I-02-04-00007-00Produced forUnited States Agency for International DevelopmentAuthorsJacob WilliamsRTI International3040 Cornwallis RoadPost Office Box 12194Research Triangle Park, NC 27709-2194andJoao PintoUnidade de Parasitologia Médica/CMDT.LAInstituto de Higiene e MedicinaTropical, Universidade Nova de LisboaRua da Junqueira 100, 1349-008 Lisboa, PortugalRTI International is one of the world’s leading research institutes, dedicated to improving the human condition by turning knowledge into practice. Our staff ofmore than 2,800 provides research and technical expertise to governments and businesses in more than 40 countries in the areas of health and pharmaceuticals,education and training, surveys and statistics, advanced technology, international development, economic and social policy, energy and the environment, andlaboratory and chemistry services. For more information, visit www.rti.org.RTI International is a trade name of Research Triangle Institute.The author’s views expressed in this publication do not necessarily reflect the views of theUnited States Agency for International Development or the United States Government.

AcknowledgementsJ. Derek Charlwood (Liverpool School of Tropical Medicine) and Carla A. Sousa (Instituto deHigiene e Medicina Tropical-IHMT), for contributed photos to the manual.The following provided critical review to the contents of the manual: Maria Paz Ade (PanAmerican Health Organization-PAHO/WHO), Allison Belemvire (USAID), Keith Carter (PanAmerican Health Organization-PAHO/WHO), Gracella W. Cooper (Liberia National MalariaControl Program), Rainier Escalada (Pan-American Health Organization-PAHO/WHO),Christen Fornadel (USAID), Christian Frederickson (Pan-American Health OrganizationPAHO/WHO), Michael Macdonald, Jake O’Sullivan (RTI International), Norma Padilla (Centrode Estudios en Salud, Universidad del Valle de Guatemala), Carla A. Sousa (IHMT), Marco FidelSuarez, Kathryn Welter (RTI International), and Susan Youll (USAID).iii

Table of ContentsPageAcknowledgements .iiiList of Figures.viList of Tables .viiIntroduction . 1Purpose of the manual. 1Target audience of the manual . 2List of Useful Terms . 4Unit 1 Malaria Control and the Role of Entomology . 61.1Major components of malaria control programs . 61.2Community education. 91.3Basic principles of planning malaria vector control and the role of entomology . 9Unit 2 Biology of Malaria Vectors . 112.1Malaria . 112.2Life-cycle of the Anopheles mosquito . 112.3Larval habitats and factors affecting adult production from aquatic habitats . 132.4Characteristics of medical importance in adults . 15Unit 3 Mosquito Anatomy and Identification . 163.1How to distinguish anopheline eggs from other culicines . 163.2How to distinguish anopheline larvae from other culicines . 173.3The pupa . 183.4How to distinguish adult anopheline and culicine mosquitoes . 193.5Methods for mosquito species identification . 21Unit 4 Diversity of Malaria Vectors . 234.1Sibling species complexes . 234.2Malaria vectors in the Americas . 244.3Malaria vectors in Africa . 254.4Malaria vectors in Asia . 26Unit 5 Mosquito Collection (Larvae) . 295.1Sampling methods . 30iv

5.2Records of collection . 325.3Transportation of live larvae . 325.4Preserving samples . 335.5Estimation of larval parameters . 33Unit 6 Mosquito Collection (Adult) . 356.1Adult mosquito collection methods . 356.2Records of collection . 426.3Preservation of samples . 42Unit 7 Preparation and Storage of Mosquito Samples . 437.1Main laboratory techniques . 437.2Preparation of mosquito samples . 457.3Essential materials and equipment. 467.4Good laboratory practices . 46Unit 8 Malaria Transmission Indices and Factors Affecting Transmission . 488.1Determining which mosquito transmits malaria (vector incrimination) . 488.2Techniques for vector incrimination . 498.3Estimation of transmission indices . 508.4Factors affecting malaria transmission . 54Unit 9 Essentials of Rearing Mosquito Colonies in the Laboratory . 559.1The insectary and basic operations . 559.2General conditions for rearing mosquitoes . 56Unit 10 Insecticide Susceptibility and Cone Bioassay Tests . 6010.1Why determine the susceptibility of malaria vectors to insecticides? . 6010.2Preparation of test vectors for susceptibility and cone bioassay evaluations . 6110.3Determining the susceptibility of adult mosquitoes . 6110.4Residual Efficacy of Insecticide on Sprayed Surfaces (WHO 1998, 2005) . 64Annex I Sample of Training Curriculum and Schedule for a Basic Entomology TechnicianCourse. 67Annex II Examples of Data Collection Forms for Larval and Adult Mosquito Surveys . 75v

List of FiguresFigure 1. Stages of the Anopheles mosquito life-cycle . 12Figure 2. Anopheles male mosquitoes form swarms at dusk for mating . 13Figure 3. Types of mosquito breeding sites . 15Figure 4. Examples of Aedes, Culex and Anopheles eggs. 17Figure 5. Anatomy of Anopheles larva . 17Figure 6. Differences between anopheline and culicine larvae . 18Figure 7. A pupa of Anopheles. 19Figure 8. Anatomy of an adult mosquito . 20Figure 9. Differences in the head of male and female anopheline and culicine mosquitoes . 20Figure 10. Resting position of culicine and anopheline adult mosquitoes . 21Figure 11. Main materials for larval collections. 30Figure 12. Larval collection by dipping . 31Figure 13. Larval collection by pipetting . 32Figure 14. Main materials for hand collection of mosquitoes . 36Figure 15. Human landing catch. 37Figure 16. Pyrethrum spray sheet collection . 39Figure 17. Outdoor resting collections. 40Figure 18. Hand collection of indoors resting mosquitoes . 41Figure 19. Exit trap . 41Figure 20. Abdominal condition of a female mosquito according to the gonotrophic state . 49Figure 21. Image of an insectary showing larval trays and adult cages . 55Figure 22. Larval tray with eggs and 1st instar larvae . 57Figure 23. Separating pupae from larvae with a pipette . 59Figure 24. Selection of insecticide resistance in vector populations . 61Figure 25. WHO test tubes for susceptibility testing . 62Figure 26. Lining the test tubes with impregnated papers . 63Figure 27. WHO cone bioassay on a wall . 65Figure 28. WHO cone bioassay on an insecticide treated bednet . 66vi

List of TablesTable 1.Malaria vector control measures (adapted from WHO, 2006) . 7Table 2.Requirements for successful implementation of major vector controlinterventions (adapted from WHO, 2006) . 8Table 3.Type of preservation of mosquito body parts to be used in laboratorytechniques . 46vii

IntroductionMalaria remains a major cause of death and sickness in most tropical regions of the world,where it is endemic in 106 countries. In 2010, about 81% of the total 216 million malaria casestook place in Africa, and 13% of cases occurred in Southeast Asia1. The largest proportion(91%) of the estimated 665,000 annual deaths from malaria occurs in Africa, mainly affectingchildren under five years old (86%). In the region of the Americas, over 670,000 confirmedmalaria cases occurred in 2010, with 133 malaria-attributed deaths. Transmission is active in 21countries putting about 20% of the population of the Americas at risk. Malaria imposes severeconstraints on economic development and is an important cause of poverty in most diseaseendemic countries.Although there has been sharp increase in funding for malaria control, disease reduction targetsset by Roll Back Malaria2 and National Malaria Control Programs still remain unachieved inmany countries. This is partly due to the lack of capacity in generating adequate knowledge onlocal disease epidemiology to inform cost-effective implementation and program management.In particular, capacity for entomological monitoring and surveillance is still rudimentary in manyendemic countries. There is an urgent need for National Malaria Control Programs to createadequate numbers of trained personnel to effectively participate in malaria control activities andsupport generation.Purpose of the manualA two-tier training course for entomology technicians has been developed aimed at facilitatingthe strengthening of core competencies for entomological monitoring and surveillance indisease endemic countries. This manual is aimed at guiding a basic level (Tier-1) entomologycourse, covering:1. The life-cycle and bionomics of mosquitoes;2. Adult and larval sampling, mosquito identification and incrimination of malaria vectors;3. Primary malaria transmission indices and what they represent;4. Malaria vector control and current primary interventions;5. The role of entomology in vector control;6. Basic principles for laboratory rearing of mosquitoes;7. Tests of mosquito susceptibility and residual efficacy of insecticides used in vectorcontrol.1WHO (2009). World Malaria Report 2011. World health Organization. Geneva, Switzerland(http://www.who.int/malaria/world malaria report 2011/en/)2Roll Back Malaria – Global Malaria Partnership (http://www.rbm.who.int/index.html)1

This manual presents the basic issues that are critical to understanding the primary educationalgoal of each subject area. It is however anticipated that the training course will provideextended opportunities for field work to assure a fuller learning experience and consolidatepractical skills/competencies. Adult learning and participatory format is anticipated, in whichstudents should be encouraged to find out things for themselves and from each other. A sampleof the curriculum and schedule for the basic entomology technician course can be found inAnnex I.Target audience of the manualThis basic manual targets district level personnel in malaria endemic countries who willnormally form the cadres that collect and report on local entomological indicators in support ofvector control programs. They will normally have secondary level education or diploma in asubject area that lends itself to training in entomology.Further readingsThis manual was prepared based on several existing guidelines, manuals and published articles,including:1. Benedict M (2009). Methods in Anopheles research. Malaria Research and ReferenceReagent Center. Version 3. 264 pp2. Hay SI, Sinka ME, Okara RM, Kabaria CW, Mbithi PM, Tago CC, Benz D, Gething, PW,Howes RE, Patil AP, Temperley WH, Bangs MJ, Chareonviriyaphap T, Elyazar IR, HarbachRE, Hemingway J, Manguin S, Mbogo CM, Rubio-Palis Y, Godfray HC (2010) Developingglobal maps of the dominant Anopheles vectors of human malaria. PLoS Medicine 7:e1000209.3. Manguin S, Garros C, Dusfour I, Harbach RE, Coosemans M (2008). Bionomics,taxonomy, and distribution of the major malaria vector taxa of Anopheles subgenus Cellia inSoutheast Asia: an updated review. Infection, Genetics and Evolution 8: 489-503.4. Service MW, Townson H (2002). The Anopheles vector. In: Essential Malariology. Eds: DAWarrell and HM Gilles. 4th Ed. Arnold Publishers, London. 348 pp.5. Sinka ME, Rubio-Palis Y, Manguin S, Patil AP, Temperley WH, Gething PW, Van BoeckelT, Kabaria CW, Harbach RE, Hay SI (2010). The dominant Anopheles vectors of humanmalaria in the Americas: occurrence data, distribution maps and bionomic précis. Parasites& Vectors 3: 72.6. Sinka ME, Bangs MJ, Manguin S, Coetzee M, Mbogo CM, Hemingway J, Patil AP, TemperleyWH, Gething PW, Kabaria CW, Okara RM, Van Boeckel T, Godfray HC, Harbach RE,Hay SI (2010). The dominant Anopheles vectors of human malaria in Africa, Europe and theMiddle East: occurrence data, distribution maps and bionomic précis. Parasites & Vectors 3:117.2