The Nigerian Institute of Medical Research (NIMR) has raised a significant public health alarm with the confirmed detection of a dangerous, non-native malaria mosquito within the country's borders. This discovery marks a potential turning point in Nigeria's long-running battle against the disease.
A New Urban Threat Emerges
During a December media chat at its Lagos facility, Dr. Adeola Olukosi, Director of Research and Head of the Malaria Research Group at NIMR, presented the troubling findings. She revealed that samples collected from Gombe State during routine national surveillance were identified as the invasive species Anopheles stephensi.
This identification was first made through morphological analysis and then definitively confirmed using molecular sequencing techniques at NIMR's laboratories. This is the first confirmed detection of this mosquito species in Nigeria.
Dr. Olukosi explained that Anopheles stephensi differs critically from Nigeria's traditional malaria vectors. While native species are predominantly rural, this newcomer thrives in urban, man-made environments. It breeds efficiently in clean water stored in containers, tanks, and other domestic systems commonly found in cities and towns.
Heightened Risks and Resistance Concerns
The capabilities of this new vector are particularly concerning for health officials. Anopheles stephensi is a highly competent carrier of both Plasmodium falciparum and Plasmodium vivax malaria parasites. Perhaps more alarming is its ability to survive extremely high temperatures during the dry season, a period when malaria transmission typically declines. This trait could lead to year-round, sustained transmission cycles.
Dr. Olukosi warned that the species' genetic profile suggests a worrying trend: resistance to multiple classes of insecticides. This makes it exceptionally difficult to control once it becomes established in an area. The experience of countries like Ethiopia, where the mosquito caused significant outbreaks after going initially unrecognized, serves as a cautionary tale for Nigeria.
Malaria Burden and the Imperative for Vigilance
This discovery comes against the backdrop of Nigeria's already staggering malaria burden. The country accounts for approximately 25 to 31 percent of global malaria cases and deaths, with the severe Plasmodium falciparum strain being dominant. Transmission patterns vary, from perennial in the south to seasonal in the north.
Dr. Olukosi reiterated that malaria research and support for the National Malaria Elimination Programme (NMEP) are core to NIMR's mandate. The institute's work includes:
- Sentinel surveillance and therapeutic efficacy studies to monitor drug effectiveness.
- Molecular surveillance to predict emerging drug resistance early.
- Entomological research that has already informed a national shift to more effective, combination insecticide-treated nets.
She noted that recent studies show currently recommended antimalarial drugs remain effective, with no immediate need for a policy change. However, insecticide resistance in existing vectors is widespread and complex.
Through collaborations like the West African Network for TB, AIDS and Malaria and the Malaria Genomic Epidemiology Network, NIMR tracks malaria evolution across Africa. The confirmation of Anopheles stephensi underscores a critical need: sustained investment in surveillance, research, and a coordinated, evidence-driven national response to prevent this new threat from eroding hard-won gains in malaria control.
