An automated wastewater sampling device installed in Garoua, northern Cameroon, has improved the performance of a polio surveillance site, raising its detection performance indicator from 16.6% to 44.4%, according to the World Health Organization (WHO). The equipment, deployed at the Pont Antenne Bibemiré surveillance site in the Garoua II health district, makes Cameroon one of ten pilot countries to benefit from the Global Water WS700, a device designed to strengthen environmental surveillance of poliomyelitis.
The sampler was handed over to health authorities in the North Region on June 27, 2026, and used for three sampling operations in July, August, and September. All three samples, analyzed at the Centre Pasteur du Cameroun in Yaoundé, tested positive for non-polio enteroviruses. These results do not mean that polioviruses were detected. Instead, the presence of non-polio enteroviruses helps assess whether the surveillance site and sampling equipment can successfully collect viruses present in wastewater.
In an article published on October 14, the WHO explained that the Pont Antenne Bibemiré site was selected after an assessment conducted in May 2026. Established in August 2022 in the Foulbéré health area, the site had consistently recorded a non-polio enterovirus isolation rate below 40%, putting it at risk of closure. With the new equipment, the WHO hopes the site's performance rate will exceed 50% by December 2026. The improvement recorded so far suggests that automated sampling may help address some of the weaknesses identified in the site's previous collection methods.
The device automates part of the wastewater collection process previously carried out manually by health workers. For the first sampling operation, the equipment, installed on July 6, was programmed to collect 600 milliliters of wastewater every ten minutes between 4 a.m. and 6:30 a.m.
According to local health teams, this period corresponds to the time when wastewater channels receive some of the first household fecal waste of the day. The operation collected a total of nine liters of wastewater, one liter of which was sent to the laboratory for analysis.
Automation also reduces the risks faced by health workers responsible for collecting samples. Juslain Alban Chedjou, head of the Garoua II health district, explained that before the device was installed, staff had to walk through wastewater channels very early in the morning to collect samples from multiple locations. Those operations exposed workers to possible infections and injuries. The automated system reduces the need for direct contact with wastewater during collection.
The Global Water WS700 runs on a rechargeable battery and uses a pump to collect successive samples over several hours. Its purpose is to produce a composite sample that better represents wastewater conditions than a sample collected at a single location or at one particular moment.
Wastewater surveillance complements the monitoring of acute flaccid paralysis, which remains the reference method for polio surveillance. Environmental sampling provides an additional way to detect poliovirus circulation, including in areas where no patient with paralysis has yet been identified. According to the WHO, environmental surveillance detected 34 polioviruses in Cameroon between 2019 and 2025, compared with 18 detected through acute flaccid paralysis surveillance during the same period.
Cameroon currently operates 18 active environmental surveillance sites across nine of its ten regions. The Northwest Region remains the only region outside the network.
Thierry Christophe Yamb