PMI has supported entomological monitoring in Nigeria since 2012. The PMI AIRS project conducted entomological monitoring along with an IRS pilot in Nasarawa in 2012 and 2013. In 2014, monitoring expanded to six sites (Enugu, Jigawa, Lagos, Nasarawa, Plateau and Rivers) and to Sokoto and Jigawa in 2015. In 2016, Akwa Ibom, Bauchi, Ebonyi, and Oyo replaced Enugu, Lagos, Rivers, and Plateau, and monitoring continued in Nasarawa and Sokoto. Through AIRS and then VectorLink, entomological monitoring continued at these six sites in 2017 and 2018. In year two of the VectorLink project, longitudinal monitoring of vector bionomics continued in the six sites as well as in Plateau. The project also performed insecticide resistance monitoring in all seven PMI-focus sites as well as Benue, Zamfara, Cross River, and Kebbi. From October 2019 to September 2020 (year three of the project), VectorLink conducted entomological monitoring in 11 sites—monthly vector surveillance and longitudinal monitoring was conducted in five sites (Akwa Ibom, Ebonyi, Oyo, Plateau, and Sokoto), while insecticide resistance monitoring only was done in Bauchi, Benue, Cross River, Kebbi, Nasarawa, and Zamfara. Monthly surveillance has continued in the 11 sites during year four (October 2020-September 2021). In addition to the six sites where insecticide resistance monitoring was conducted in 2020, the project added four non-PMI-focus sites (Bayelsa, Enugu, and Federal Capital Territory Abuja, and Bonny Island in Rivers State) in 2021.
Results from VectorLink Nigeria’s entomological surveillance and insecticide resistance monitoring activities have highlighted an urgent need to develop and implement appropriate insecticide resistance management strategies in areas with high intensity of resistance. In particular, the data collected helped guide PMI’s decision to procure and deploy piperonyl butoxide (PBO) nets in Ebonyi (2019) and Oyo (2020) and Interceptor G2 (IG2) nets in Oyo (2021) and Kebbi (2022) to combat resistant malaria vectors with metabolic resistance mechanisms.
From October 2021 to September 2022, the PMI VectorLink Nigeria project continued to work with the National Malaria Elimination Program (NMEP), the Nigerian Institute for Medical Research (NIMR), State Malaria Elimination Programs (SMEPs), and PIs in Nigerian Universities to monitor trends in vector bionomics (longitudinally), insecticide resistance, and the programmatic impact of the distribution of next-generation nets in Kebbi and Sokoto States. Key accomplishments included:
- Conducted monthly longitudinal vector surveillance in seven sentinel sites (six PMI-focus states and one non-PMI-focus state) to measure vector species composition, density, distribution, seasonality, and behavior, as well as sporozoite infection rate, parity, and blood meal sources.
- Conducted insecticide resistance testing on Anopheles gambiae s.l. in 16 sites (11 PMI-focus and five non-PMI-focus states).
- Continued to collect entomological data from Interceptor G2 and piperonyl butoxide (PBO) net monitoring sites in Kebbi and Sokoto States, respectively.
- Conducted a survey to determine the feasibility of implementing larval source management (LSM) as a supplementary approach in Kebbi State, which has the highest malaria burden in the country. A report summarizing the results is currently being finalized.
- Transitioned all entomological data collection, management, and analysis for VectorLink Nigeria-supported sites to VectorLink Collect, a District Health Information Software Version 2 (DHIS2)-based system.
Insectary and Laboratory Activities
- Managed the Nasarawa State University insectary and laboratory in Keffi in support of the project’s capacity building objectives, supporting accurate sample identification and testing of technical grade insecticides.
- Provided technical guidance and facilitatory support to Nigeria Liquefied Natural Gas (NLNG) laboratory in Bonny Island, to support their interest in expanding their entomological testing capabilities.
- Collaborated with NIMR to conduct molecular analysis on mosquito samples identified in Keffi laboratory.
- Shared all entomological data collected with NIMR for storage and management.
- Supported the training of technicians and PIs implementing field activities.
Capacity Building at National and State Levels
- Supported the development of a national vector surveillance and insecticide resistance implementation guide, containing practical guidance as well as harmonized protocols and procedures for implementation of entomological activities by the NMEP and its partners. The guide was reviewed, validated by key stakeholders, and approved by the country’s Integrated Vector Surveillance Technical Working Group in February 2022.
- Facilitated the review of entomological monitoring data with stakeholders to inform and improve decision-making on vector control.
- Provided technical expertise during a refresher training organized by the NMEP on basic morphological identification and entomological methods for entomology technicians.
- Collaborated with the NMEP, NIMR, and other malaria partners to derive aggregates from a standard list of entomological indicators measured by all partners conducting entomological activities in Nigeria.
- Supported the NMEP through local and international procurement of materials required for insecticide resistance management activities in Global Fund-supported entomology sites.
Streamlined Durability and Program Monitoring
- Supported the NMEP to conduct pre-distribution bioassays on a sample of IG2 ITNs withdrawn from those planned for distribution in Kebbi State in 2022, as a first step in streamlined ITN durability monitoring.
- Concluded a programmatic assessment of PBO ITNs distributed in November 2019 in Ebonyi State. Finalized an interrupted time series analysis and estimated the impact of PBO ITNs on key entomological and epidemiological indicators such as confirmed case incidence two years before and two years after net distribution. Results will be presented in late 2022 at ASTMH and in-country and a manuscript is currently under development.
- Developed a baseline presentation summarizing entomological and epidemiological data prior to IG2 and PBO ITN distributions in Kebbi and Sokoto States, respectively, as part of an ongoing program monitoring activity.