VECTOR SURVEILLANCE & CONTROL IN NIGERIA: Mapping Of Mosquito Species In the Six Geopolitical Zones.

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VECTOR SURVEILLANCE & CONTROL IN NIGERIA:

MAPPING OF MOSQUITO SPECIES IN THE SIX GEOPOLITICAL ZONES.

BY

ANUMBA JOSEPH UCHE NATIONAL ARBOVIRUS AND VECTORS RESEARCH CENTRE (NAVRC).

BACKGROUND.

The National Arbovirus and Vectors Research Centre (NAVRC) in Nigeria is set to launch a

mosquito (Anopheles, Culex and Aedes) species surveillance map to help detect the spread/

vector distribution of various arthropod borne viruses (Arbovirus) in the six geopolitical zones

of Nigeria.

A pilot study kicked off in the South Eastern part of Nigeria (Enugu and Anambra State). The

proposed methodology of the project is the integration of Geo-informatics (Geographical

Information Systems- GIS) in real time vector surveillance. This novel approach intends to

forecast the tendencies for Arbovirus disease outbreaks in communities across the geopolitical

zones in Nigeria as such, the National Arbovirus and Vectors Research Centre in Nigeria will be

able to monitor mosquito population and provide early warning signals against impending

threats from malaria and Arbovirus disease outbreaks.

This has become pertinent due to the re-emergence of yellow fever and other Arboviral diseases

outbreaks in some parts of the country.

This approach has been tested and successfully implemented by the Venezuelan Government

and some countries (http://dengue.pchrd.dost.gov.ph/).

JUSTIFICATION.

In lieu of the unrelenting efforts of the Nigerian Government to combat the scourge of malaria

and various Arbovirus caused by the mosquito spp vectors, a need exists to further develop new

technologies, such as remote sensing and geographic information systems analysis, for

estimating arthropod vector abundance in aquatic habitats and predicting adult vector

population outbreaks around the 36 states including the Federal Capital Territory, Nigeria. This

is in line with the mandate and core objectives of the National Arbovirus and Vectors Research

Centre under the Jurisdiction of the Federal Ministry of Health.

VECTOR SURVEILLANCE & CONTROL IN NIGERIA: Mapping Of Mosquito Species In the Six Geopolitical Zones.

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GOALS & OBJECTIVES.

The epidemiological and Geographical Information System (GIS) mapping of mosquito species

in Nigeria intends to develop a comprehensive state of the art web based GIS database by

integrating contemporary entomological field surveillance and the use of remote sensing to

achieve multiple objectives, focusing on mosquito spp management as a potential approach to

assist in minimizing disease (arboviral) risks and outbreaks in Nigeria.

The project will inform and educate (professionals and the public); empower decision-making

at all levels; help in planning and tweaking clinically and cost-effective actions, in predicting

outcomes before making any financial commitments and ascribing priorities in a climate of

finite resources; change practices; and continually monitor and analyse changes, as well as

sentinel events involved in malaria and Arboviral disease control programmes.

Consequently, the project will develop reliable baseline data that will help in implementing and

monitoring the progress of various intervention measures deployed to combat malaria and

Arbovirus diseases in the country.

The ultimate goal is to illuminate the road towards implementing a comprehensive national,

multi-agency spatio-temporal health information infrastructure functioning proactively in real

time.

VECTOR SURVEILLANCE & CONTROL IN NIGERIA: Mapping Of Mosquito Species In the Six Geopolitical Zones.

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METHODOLOGY & REQUIREMENTS.

Consensus

The format and contents of the intended surveillance and control system will be designed in

consultation with experts in public health surveillance, disease control and prevention from the

Federal level and their respective counterparts in the State Ministry of Health (SMoH), as well

as Information Technology (IT) developers. A detailed analysis of the available epidemiologic

surveillance and vector control information systems, data and results from pilot studies (in

South East Nigeria) will be used to assess the performance of the Ministry’s Health Information

System so as to debug and identify shortcomings prior to nationwide deployment and use.

Conceptual Framework.

Epidemiological and entomological data will be entered and analysed to produce risk maps

which are then used to direct vector control activities. New epidemiological and entomological

data will be used to assess the impact of control activities thus generating a knowledge database

which can be used to evaluate cost-effectiveness of control measures, accountability and

operational research. Control interventions will be directed according to the risk maps and

entered into the system for impact evaluation in the reduction of disease cases and/or vector

population.

System Development

The GIS for surveillance and control mosquito spp will be constructed in three phases. In the

first phase, an interoperable geocoding web based tool with a mapping application, designed to

work with the Epidemiologic Surveillance Platform (EPS) will be developed to geocode the

place of residence (town blocks level) of probable arbovirus and vector cases. Then, a

modification may be made on the EPS to enable geocoding through online calls in order to geo-

reference the residence of probable cases. The EPS shall be operated nationwide by the

jurisdictional, state and social security system epidemiologists in coordination with the

National Arbovirus and Vectors Research Centre (NAVRC).

The second phase will include the development of a set of modules for entomological

surveillance, planning and monitoring control activities, as well as a module for downloading

information to the hard drive of local entomologists’ and epidemiologists’ computers. Vector

surveillance is based on contemporary field surveillance and ovitrap data; for this purpose, a

VECTOR SURVEILLANCE & CONTROL IN NIGERIA: Mapping Of Mosquito Species In the Six Geopolitical Zones.

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modification of the geocoding tool will be developed to geocode ovitraps. After an ovitrap is

geo-referenced, data on egg counts are entered into Vector GIS via web based formularies.

Another set of web based formularies will be developed to allow entering data on vector control

activities carried out at the local level. Also, the platform will allow entering data gathered in

entomological surveys, such as the number of water containers per house, the number of

positive containers per house and the number of pupae- positive containers per house as well as

adult mosquitoes gotten via Pyrethrum Knockdown Collection (PKC) and dummy human bait

if necessary.

These formularies shall be linked to town blocks using the National Geo- statistical Framework

(NGF) and the federal electoral identification codes if available. The modules for control and

planning include tools to visualize temporal and geographical accumulation of cases (clusters of

malaria/arbovirus transmission) in order to direct vector control activities. It will also include a

tool to print maps to be used in field activities; these maps shall have the id code of each block

to allow recording of surveillance/control activities.

The third phase shall be completed with a reporting module and an improved geographic

visualization tool that combines epidemiologic, entomological and control data into a single

mapping window.

Each of these phases will be implemented gradually in the States with most arbovirus/vector

incidence, and group of researchers and IT specialists, along with NAVRC personnel trained

state and jurisdictional epidemiologist in its use.

Statistical Analysis.

Identification of areas of probable cases accumulation in time (clusters) will be carried out using

a nearest neighbor hierarchical clustering algorithm. This statistical methodology is used in

epidemiology to detect areas of high accumulation of cases based on the distance between them.

For its application in malaria/arbovirus transmission, a minimum number of cases to conform a

cluster will be set. The algorithm shall be run every week using the EPS geo-referenced

epidemiological data of the three previous weeks. In this way the entire national territory could

scanned every week in search for areas with an accumulation of at least five cases separated by

500 meters or less within a three weeks’ time window.

VECTOR SURVEILLANCE & CONTROL IN NIGERIA: Mapping Of Mosquito Species In the Six Geopolitical Zones.

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At the end of the each surveillance and data analysis, a standard transmission risk index shall

be produced for malaria and arbovirus disease causing mosquitoes:

High transmission risk=high entomological risk and presence of arbovirus probable

cases

Moderate high transmission=Moderate high entomological risk and presence of

arbovirus probable cases.

Moderate low transmission=Moderate low entomological risk and presence of

arbovirus probable cases

Low transmission risk=no arbovirus probable cases detected.

Enquiries: National Arbovirus and Vectors

Research Centre, Enugu State- Nigeria.

Contact: Anumba Joseph Uche

anumbajoe@gmail.com(2348032173955) http://linkedin.com/in/anumbajoe