The Nigeria Centre for Disease Control and Prevention (NCDC) is aware of the outbreak of dengue fever reported in Sokoto State in November 2023. So far, 71 suspected cases, 13 confirmed cases and zero deaths have been reported in the state. Currently, the virus has been reported in three (3) local government areas (LGAs): Sokoto South (60 cases), Wamako (3 cases) and Dange Shuni (1 case). The majority of the suspected cases reported fall between the age range of 21- 40 years.
The NCDC-led multisectoral National Emerging Viral Haemorrhagic Diseases Technical Working Group (NEVHD-TWG) collaborating with partners and relevant stakeholders, has conducted a rapid risk assessment to guide in-country preparedness activities. The NEVHD TWG coordinates preparedness efforts for Ebola virus disease and other emerging viral haemorrhagic fever diseases.
Based on a dynamic risk assessment, the current risk level of the dengue outbreak has been determined to be MODERATE for the following reasons:
• Only Sokoto state has reported confirmed cases so far.
• Only three (3) of the 23 LGAs in the states are affected.
• No severe disease or death has been reported.
• Sokoto state can respond to the outbreak, building on lessons learnt from prior dengue virus outbreaks (2016 and 2019).
• No healthcare worker infections or deaths have been reported.
• There, however, remains a low index of suspicion among healthcare workers (HCWs).
There is currently adequate in-country capacity (including technical, health workforce and diagnostic) to respond effectively in the event of a large-scale outbreak. Nigeria has also responded to viral haemorrhagic fever epidemics like the Ebola Outbreak in 2014 and subsequently Lassa fever. This has built our preparedness and response capabilities for viral haemorrhagic fevers like dengue virus (DENV) over the years.
Currently, there is a diagnostics capacity for the dengue virus (DENV) at the NCDC National Reference Laboratory (NRL) in Abuja and the Usman Dan Fodio University Sokoto Teaching Hospital Laboratory Centre for Human and Zoonotic Virology (UDUTH). However, the NCDC will proceed to optimise existing Lassa fever testing laboratories and others within the NCDC national laboratory network for DENV diagnosis to improve preparedness and readiness in the event of a large-scale outbreak. An effective response system is in place with the availability of control capacities (including trained rapid response teams, and an effective infection, prevention, and control programme) to limit the risk of spread to other states.
In Sokoto state, public health actions have been taken to ensure the control of the spread of the outbreak, this includes.
• Dissemination of a Public Health Advisory to the public and media by the Sokoto State Honourable Commissioner for Health (HCH).
• Sensitisation of clinicians across the state on Dengue fever on the need for a high index of suspicion.
• Sensitisation of LGA surveillance officers to enhance surveillance of Dengue fever.
• Media engagements including phone-in programs to ensure public awareness of Dengue fever.
• Collaboration with the Ministry of Environment to improve sanitation and clearing of mosquito breeding sites in the metropolitan LGAs.
• Collaboration with Malaria Control Agency for a Reactive Fumigation in the Metropolitan LGAs.
Concurrently at the national level, measures have been taken by the NEVHD-TWG following input from arbovirus institute and review of entomological surveillance data to inform action and strengthen preparedness for a large-scale DENV outbreak in Nigeria. These include:
• The NCDC Incident Coordination Centre (ICC) has been activated in alert mode.
• Development of an emergency incident action plan for DENV has commenced.
• A review of case definitions for DENV.
• The National Emergency Operations Centre (EOC) has sent out warning notifications to all Subnational Public Health Emergency Operations Centres (PHEOCs).
• Follow-up of suspected cases has commenced.
• Trained Rapid Response Teams are on standby to be deployed in the event of a nationwide outbreak.
• A medical countermeasures plan is being developed.
• A risk communication and engagement strategy has been developed to strengthen preparedness activities which include a review of risk communication protocols, plans, and messages in the event of a wider outbreak.
• Proposed research project with the National Arbovirus and Vectors Research Centre across the 6 Geopolitical zones to better understand the disease vector.
• Nigeria has an active infection prevention and control (IPC) programme nationwide with guidelines and training packages developed for healthcare workers.
About Dengue Fever
Dengue fever is a viral infection caused by the dengue virus (DENV) and transmitted to humans through the infected mosquito’s bite. Human-to-human transmission of the virus has not been established. DENV is found in tropical and sub-tropical climates, mostly in urban and semi-urban areas worldwide.
Most people with dengue have mild or no symptoms and will get better in 1–2 weeks. Rarely, dengue can be severe and lead to death. If symptoms occur, they usually begin 4–10 days after infection and last for 2–7 days. Symptoms may include high fever (40°C/104°F), severe headache, pain behind the eyes, muscle and joint pains, nausea, vomiting, swollen glands, and rash. Individuals who are infected for the second time are at greater risk of severe dengue.
Available data shows that prevention and control of DENV infection depend on vector control. There is no specific treatment for dengue, however, early detection and prompt initiation of supportive treatment have been shown to significantly reduce death.
Nigerians especially people living in Sokoto are urged to adhere strictly to the following preventive measures:
• Wear clothes that cover as much of your body as possible to avoid mosquito bites.
• Sleep under insecticide-treated mosquito nets and use insect-repellent in sleeping areas.
• Ensure proper sanitation of your environment to reduce the breeding of mosquitoes.
• Call 6232 or other dedicated hotlines by State Ministries of Health to ensure all persons with suspected symptoms of dengue fever described above are promptly taken to designated healthcare facilities by the responsible State Ministry of Health for prompt diagnosis and initiation of supportive treatment.
The Nigeria Centre for Disease Control and Prevention (NCDC) is the country's national public health institute, with the mandate to lead the preparedness, detection, and response to public health emergencies. The Bill for an Act to establish NCDC was signed into law in November 2018, by President Muhammadu Buhari. The mission of the NCDC is 'To protect the health of Nigerians through evidence-based prevention, integrated disease surveillance and response, using a One Health approach, guided by research and led by skilled workforce'.
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Dr Ifedayo Adetifa
Nigeria Centre for Disease Control and Prevention.