Zika widely in circulation, says disease centre

The verdict out: The dreaded Zika virus is widely circulated in Nigeria. A review of current epidemiology, risk assessment to public health and interim recommendations for public health response to Zika virus in Nigeria, released yesterday, by the Nigeria Centre of Disease Control (NCDC) Abuja concluded: “Previous evidence of detection of Zika virus in man, and antibodies to Zika virus in Nigerian populations, together with the presence of the vectors indicate that the virus is widely circulated in Nigeria. Thus, in the absence of continued surveillance or periodic national surveys, the epidemiology of the Zika virus in Nigeria remains poorly understood.”

The centre’s Director General and Chief Executive Officer, Dr. Chikwe Ihekweazu, who authorised the review, said majority of those infected with the virus remain asymptomatic and for those who develop symptoms, fever, rash, conjunctivitis, headaches, muscle and joint pains typically start three to six days after infection.

He added that the virus might stay in the body for weeks following infection.Ihekweazu said the current epidemiology of Zika in Nigeria has not been well documented or understood due to paucity of recent data.

He noted that the virus shares a similar vector, the Aedes (Steogmyia) mosquitoes, also responsible for other flavivirus infections recorded in the country such as such as yellow fever and dengue.

Ihekweazu revealed that the environmental and human behavioural risk factors in areas with reported Zika outbreaks were similar to those found in Nigeria and would thus favour the circulation of Zika.

He said possible cross-reaction with other endemic flaviviruses like yellow fever and dengue; genetic host factors protecting against infection or disease; low vector competence and transmission efficiency; lack of diagnostic testing; and the absence of systematic surveillance are potential limitations to detect on-going transmission of Zika in the country.

Ihekweazu said in principle, all countries with presence of Aedes (Steogmyia) albopictus and Aedes (Steogmyia) aegypti mosquitoes are at risk of sustained transmission and human activity aids the spread of the virus to locations far beyond the normal range for the vector.

He stressed that in the light of the review, NCDC plans to initiate surveillance to understand and monitor the epidemiology of virus in the country for appropriate interventions.