Nigeria has been reporting cases of dengue (DENV) for many years. The first infections were detected between 1964 and 1968 in febrile patients attending the outpatient clinic of the University College Hospital Ibadan. The detected serotypes were mainly 1 and 2 (DENV-1 and DENV-2).
Although seroepidemiological surveys have shown that virus activity is widespread in the country, there is scant information about the disease, and dengue receives little attention largely because it presents as classic dengue characterized by fever, myalgia, headache, arthralgia, retroorbital pain, gastrointestinal symptoms, and rash.
In 1973, the first documented dengue outbreak in Nigeria occurred in Abeokuta during which six strains of DENV-1 were isolated. All affected patients had classic dengue hemorrhagic fever, and no cases of dengue shock syndrome were identified. Few or no DENV surveillance activities were carried out between the 1980s and 2010, during which sporadic dengue outbreaks occurred in other parts of Africa, accompanied by the emergence of dengue hemorrhagic fever in some countries.
Serotypes 3 and 4 (DENV-3 and DENV-4) were detected in Nigeria, with the appearance of dengue hemorrhagic fever for the first time in 2014.
Available evidence suggests that only A. aegypti is involved in dengue transmission in the country, as several DENV isolates were obtained from this mosquito species and none from A. albopictus.
Serological tests have revealed a prevalence of IgM antibodies against dengue of 0.67% in suspected malaria or typhoid patients in Maiduguri, 30% in febrile children in Ilorin, 23.4% in Ibadan, 17.2% in Ogbomoso, and the presence of neutralizing antibodies against dengue virus type 3 in northeastern Nigeria. In two separate studies, a prevalence of 2.2% and 35% of NS1 antigen was found in Jos and Ibadan, respectively.
Poor surveillance, lack of reporting, and misdiagnosis of the disease are significant issues.
