In the developing world, acute febrile illness (AFI) is a common reason for seeking healthcare, and infections leading to AFI are responsible for the majority of childhood deaths after the neonatal period. In Kenya, more than 10 million episodes of AFI are treated annually among children under 5 years, with many clinically managed as malaria without parasitological confirmation.

On February 17th, 2024, reports of an outbreak of an unknown illness surfaced on social media in Mwingi North Sub-county, Kitui County. Prompted by this alert, the County dispatched a team for investigation. The investigation uncovered two reported cases resulting in fatalities, both from Mukindu village. Additionally, two other cases were identified: one was diagnosed and treated for malaria and intestinal worms at Ishiara Hospital, while another received treatment for malaria at Konyu dispensary and recovered. Situated along the River Tana, the area typically experiences an increase in malaria cases post-rainfall.

Further investigation involved malaria testing of ten individuals, revealing three positive cases and seven negatives. These findings shed light on malaria within the community and underscored the need for continued monitoring and intervention. Therefore, the Ministry of Health, through the Disease Surveillance and Response Unit, deployed a team from Kenya Field Epidemiology and Lab Training program to support the county in response.

The objectives of the investigation which was conducted between March 20 – 29, 2024 included

• To determine the magnitude of the outbreak of the unknown illness.
• To identify the etiology of the unknown illness in Mwingi North Sub County, Kitui.
• To assess the case management of AFI.
• To determine possible drivers associated with the unknown illness.
• To support prevention and control mechanisms.