Yellow fever outbreak fears face Nigerian health officials
The last time there has been a yellow fever epidemic in the African nation of Nigeria was three decades ago; however, health officials in Abuja are concerned because there has not been nationwide vaccination against the mosquito borne viral disease since, putting over 100 million Nigerians at risk, according to a Leadership report Oct. 24.
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According to the report, the warning is coming amidst recent outbreak of yellow fever in six districts of Cameroon bordering Cross River State, which places Nigeria at risk because it is the only country among 13 in West Africa yet to conduct mass vaccination.
The Chairman of the Expert Review Committee (ERC) on Polio Immunisation, Prof Oyewole Tomori said yesterday that 377 local government areas in 25 states in the country had been marked out as high risk states.
He warned, “We’re a large population and if we don’t conduct this mass vaccination, we cannot predict what will happen.”
Yellow fever is found in 33 countries in Africa and 9 in South America and the Caribbean islands.
There are three transmission cycles to yellow fever:
• Jungle cycle- This cycle involves the mosquitoes Aedes and Haemagogus and primates. This transmission is restricted to tropical areas of Africa and South America. A few hundred cases occur annually; mostly among young males working in forested areas.
• Intermediate cycle- This cycle occurs in savannah regions of Africa and involves humans and the Aedes mosquito.
• Urban cycle- This involves humans and the Aedes aegypti mosquito. This is the cycle where human epidemics occur.
After getting bit by an infected mosquito, the incubation time is 3-6 days. It is typically of short duration and various severities.
Mild cases are characterized by sudden onset of fever, chills, headache, backache, muscle pain and nausea and vomiting. This stage lasts about 48 hours. Most infections resolve at this stage.
About 15% of the time the disease may progress to a severe hemorrhagic fever. There is a “period of calm” of a few hours to a day.
This stage of the disease is characterized by jaundice and hemorrhagic symptoms like bleeding out the nose, gingival bleeding, and vomiting blood (may be black and look like coffee grounds).
Abnormalities in clotting factors and liver enzymes may be the result of kidney and liver failure.
Yellow fever can be laboratory diagnosed by growing the virus in cell culture, by demonstrating viral antigens, and by molecular methods like PCR.
There is no treatment for yellow fever itself, just treating the symptoms.
Yellow fever can be prevented by vaccination.
Nigeria’s last vaccination against yellow fever was in 1995 after an outbreak that lasted eight years resulted in 20,000 cases and killed more than 5,000 people.
