vector control and surveillance for malaria & other vector-borne … · 2014. 11. 19. · vbd...
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Vector Control and Surveillance for Malaria & Other Vector-Borne
Diseases
Lessons Learned
Gene Brantly
Malaria/VBD Program Elements
Integrated Vector Management– IVM policy and capacity-building– Larval control methods
Surveillance– Malaria stratification and forecasting– Regional collaboration
Overview
Malaria/VBD Program Locations
Africa – Eritrea, Ghana, Kenya, Mozambique, Tanzania, Uganda, Zambia, and regional
ANE – Nepal and South Asia regional
LAC -- regional
Overview
Malaria Vector Control Methods
Insecticide-treated bed nets
Background
Indoor spraying
Malaria Vector Control Methods
Background
Malaria Vector Control Methods
Larval control
Background
Malaria Vector Control Methods
Larval control
Background
Integrated Vector Management
DefinitionIVM is the targeted, selective use of one or more
vector control methods appropriate to local environmental and epidemiological conditions
IVM Program– Planning– Operations– M&E
Background
Key Roles for EHP
Support IVM initiatives in WHODetermine appropriate settings for malaria vector control methods– Urban and rural environments– Emphasis on larval control
Integrated Vector Management
WHO IVM Initiatives
1999 – IVM starting in Africa, led by WHO/AFRO– Roll Back Malaria focused only on ITNs
Integrated Vector Management
WHO IVM Initiatives
1999 – IVM starting in Africa, led by WHO/AFRO– Roll Back Malaria focused only on ITNs
2004– “IVM Partnership” active in 14 African countries– Similar initiative started in EMRO region– IVM adopted as WHO Global Strategic Framework– Greater support for IVM within Roll Back Malaria
Integrated Vector Management
Vector Control Methods & Settings
1999– Exclusive emphasis on insecticide-treated nets– Larval control not used in Africa
Integrated Vector Management
Vector Control Methods & Settings
1999– Exclusive emphasis on insecticide-treated nets– Larval control not used in Africa
2004– More balanced interest in all effective vector control methods– Larval control:
Strong international interest8 field studies underway in Africa (5 EHP, 3 NIAID)Appropriate in arid zones, urban areas
Integrated Vector Management
Lessons Learned
IVM is now the accepted technical framework for vector control programs for malaria and other vector-borne diseases.
Integrated Vector Management
Lessons Learned
National malaria programs want to make greater use of all proven vector control methodsProfessional training and experience in entomology and vector control are critical
Integrated Vector Management
Future Directions
Completing larval control field studiesDeveloping new models for organizing vector control – decentralized, community-basedBuilding human resource capacity in medical entomology and vector control
Integrated Vector Management
Improving VBD Surveillance
Promote standard methods for disease surveillanceClinical and lab diagnosisCase definitionReportingData managementData access and analysis
Background
Improving VBD Surveillance
Develop and promote methods for integrated analysis of epidemiological, entomological, environmental, and demographic data to better understand disease distribution
Background
Disaggregating the historical data base
Improving VBD Surveillance
FIG 1: ANNUAL TREND IN OPD CASES BY ZOBA - Hospitals and Health Centres
0
20000
40000
60000
80000
100000
1996 1997 1998 1999 2000 2001year
case
s
ANSEBA DEBUB GASH BARKA MAAKEL NRS SRS
Background
Disaggregating the historical data base
Improving VBD Surveillance
Fig.8: DEBUB - ADI QUALA
0
200
400
600
800
1000
Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02Month
Num
ber o
f mal
aria
cas
es
OPD IPD
Background
Distribution of An. gambiae s.l. in Eritrea
Improving VBD Surveillance
Background
Improving VBD Surveillance
Rainfall
010203040506070
Stream
Swamp
Rain po
olSpri
ng
DamPon
dsRive
rbed
Breeding habitat
No.
of l
arva
e/ 1
00 d
ips
Density
Larval habitats
Background
Improving VBD Surveillance
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logistic regression model of probability of village with malaria infection0 - 0.10.1 - 0.20.2 - 0.30.3 - 0.40.4 - 0.50.5 - 0.60.6 - 0.70.7 - 0.80.8 - 0.90.9 - 1No Data
% 1-15 year olds with malaria infection# 0# 0 - 0.06# 0.06 - 0.12# 0.12 - 0.19# 0.19 - 0.29
ZobaAnsebaDebubGash-BarkaMaekelNorthern Red SeaSouthern Red Sea
0.0008 0 0.0008 0.0016 Miles
N
EW
S
Key Roles for EHP
Support in Nepal, South Asia & EritreaMethods development for malaria stratification and epidemic forecasting
Surveillance
VBD Surveillance in Nepal & South Asia
1998– Substantial
data gaps for 3 VBDs
– Minimal collaboration among countries
Surveillance
VBD Surveillance in Nepal & South Asia
2004– Malaria: regional agreement on drug resistance
monitoring, recent Indo-Nepal joint study– JE: regional agreement on surveillance methods
institutionalized as part of WHO guidelines– Kala-azar: Improved diagnosis via new reference
labs in Nepal; Indo-Nepal collaboration on diagnostic methods, case reporting, and IEC
Surveillance
Malaria Surveillance in Eritrea
1999– Trends
only by year and zone
– clinical diagnosis
– Limited access to data
Surveillance
Malaria Surveillance in Eritrea
2004– Case data disaggregated to facility and period– Sentinel sites providing confirmed diagnoses– Malaria stratification complete, detailed maps in use– Zonal staff have access to case & rainfall data– Epidemic forecasts available for 2004-05 season
Surveillance
Eritrea: Malaria Incidence 1997
Insufficient data
19970 - 2525 - 5050 - 7575 - 100100 - 125125 - 150150 - 175175 - 200Over 200
100 0 100 200 Miles
N
EW
S
Surveillance
Eritrea: Malaria Incidence 1998
Insufficient data
19980 - 2525 - 5050 - 7575 - 100100 - 125125 - 150150 - 175175 - 200Over 200
100 0 100 200 Miles
N
EW
S
Surveillance
Eritrea: Malaria Incidence 2002
Insufficient data
20020 - 2525 - 5050 - 7575 - 100100 - 125125 - 150150 - 175175 - 200Over 200
100 0 100 200 Miles
N
EW
S
Surveillance
Lesson Learned
In areas prone to epidemics of malaria and other vector-borne diseases, understanding the local distribution of the disease and its relation to environmental and demographic factors will help public health officials improve the prevention and control activities they direct.
Surveillance