With the recent alarm raised by the Nigerian Centre for
Disease Control that the Zika virus vector is widely circulating in Nigeria,
experts are of the opinion that the government must step up measures against
the deadly disease.
When Brazil, in June last year experienced an outbreak of Zika
virus, a relatively unknown pathogen, not many people referred to it as a
public health challenge requiring utmost priority, until it took a new turn and
was becoming deadly, forcing the World Health Organisation (WHO) in February 1
this year, to declare it an international health emergency, requiring new and
urgent tool to eradicate.
But as Nigerians continue to see it as American and Asian
health challenge, recent development suggests Nigeria and other malaria endemic
nations are at risk of the deadly virus since its transmitter, the Aedes
mosquitois a common strain of the mosquito family known to exist in Nigeria and
other countries battling with malaria.
In fact, in a more direct statement by the Director General
and Chief Executive Officer of the Nigerian Centre for Disease Control (NCDC),
Dr. Chikwe Ihekweazu, Zika virus is already widely circulating in the country.
Shockingly, he said there was the absence of continued surveillance or periodic
national surveys, with the epidemiology of the virus still poorly understood in
the country.
Though an uncommon disease, it is not strange to Nigeria and
Africa at large. In 1960, the country experienced the first human case of the
virus, according to WHO records; that is 27 years after it was first documented
in monkeys in Uganda, an East African country, known to be a breeding region
for mosquitoes, just like Nigeria.
But the world did not take the 76 years old virus seriously
because its outbreaks were sporadic and tiny, and the disease seemed to do little
harm to humans, until recently with its recent manifestation in South America
and Asia, starting with birth deformities in newborn, among other clinical
features.
The virus is a disease transmitted by the bite of an
infected Aedesaegypti mosquito - the same mosquito strain that causes dengue
and other tropical diseases. Experts described it as a strain with white
markings on its legs and a marking in the form of a lyre on the upper surface
of the thorax. The average wing length of female Aedesaegypti mosquitoes varies
greatly between 1.67- 3.83 mm in Peruvian habitat.
According to Ihekweazu, "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, adding that the majority of those infected with the
virus remain asymptomatic and for those who develop symptoms, such as, fever,
rash, conjunctivitis, headaches, muscle and joint pains, it typically start
three to six days after infection. "The virus might stay in the body for
weeks following infection," he said.
He noted that current epidemiology of Zika in Nigeria has
not been well documented or understood due to paucity of recent data, adding
that the virus shares a similar vector, the Aedes (Steogmyia) mosquitoes, also
responsible for other flavivirus infections recorded in
the country, such as yellow fever and dengue.
"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 virus," Ihekweazu 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."
Concluding the CEO said 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 explained that in the light of the review, NCDC plans to
initiate surveillance to understand and monitor the epidemiology of the virus
in the country for appropriate interventions.
Compiled By Martins Ifijeh
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