Nigerians have been cautioned to refrain from conducting tests for yellow fever at home but, instead, consult professional healthcare providers, as there is currently no home-testing skin for the disease.
A medical laboratory scientist with Innovative Biotech Limited, Mrs. Jennifer Shoshan disclosed this during a chat with Science Nigeria today (November 17, 2022) in Abuja.
She said the fever is diagnosed with blood tests that detect disease-specific antibodies produced in response to the virus.
“This includes a common test called an ‘enzyme-linked immunosorbent assay’ (ELISA) that can detect different types of antibodies produced at different stages of the infection.
“The blood draws itself only takes a couple of minutes. The ELISA test results, however, can take anywhere from four to 14 days to receive.”
According to her, once healthcare providers suspect the presence of the fever, they generally run a test on blood serum to look for markers that are specific to the virus that cause the illness.
“Early on in the disease progression, the test may not be able to detect anything. That can be frustrating when a person wants to know why they are sick.
“Keep in mind that most cases of yellow fever do not ever progress past that point, meaning they will be sick for a few days, then recover and be just fine,” she said.
The expert said once a case has progressed to the later, toxic phase, the test is better able to detect it.
“Results, though, may take a few days to two weeks to come back,” she stressed.
Shoshan said that, seeing as 50 per cent of people in the toxic stage could die within that time, healthcare providers typically begin treatment right away based on a ‘presumptive diagnosis’.
“That means they’ll look at the symptoms along with where the person must have travelled to and when. Treatment involves managing the symptoms [through] hydration and lowering the fever, since no antiviral treatments are known to work on the virus.”
She said symptoms associated with the fever are also common in a wide array of other illnesses.
“Healthcare providers may order additional blood tests for many other diseases with a similar presentation which can include severe malaria or Dengue fever which is also caused by a member of the Flavivirus family, leptospirosis, viral hepatitis, jaundice (yellowing of the skin, from which the disease takes its name).
“For other fevers that are hemorrhagic, like liver poisoning, the healthcare provider may test the person for any number of other things, as well, depending on the specific set of symptoms and other factors, such as lifestyle or recent travel,” she said.
The expert said that knowing the basic symptoms of yellow fever and whether a person is at a heightened risk of complications is helpful if the person has been to one of the 47 countries in Africa the fever is prevalent.
According to her, if one develops a flu-like illness a few days after being bit by a mosquito in any of those regions, one must not delay in getting medical treatment.
Science Nigeria reports that, according to the World Health Organisation (WHO), since September 2017, yellow fever cases have been reported across several states in Nigeria.
From 1 January to 31 August 2021, a total of 1,312 suspected cases were reported in 367 local government areas (LGAs) across 36 states and the Federal Capital Territory (FCT).
A total of 45 blood samples were sent to the Institut Pasteur in Dakar (IPD) and 31 samples tested positive by plaque reduction neutralisation test (PRNT). Of these, 12 cases had a history of yellow fever vaccination.
Two deaths were reported among the remaining 19 non-vaccinated PRNT-positive cases (Case fatality ratio: 11 per cent. These 19 PRNT-positive cases were reported from Enugu (7), Anambra (3), Benue (3), Delta (2), Oyo (2) Niger (1) and Osun (1). Investigations into the PRNT-positive cases are ongoing.
Meanwhile, Yellow fever is an acute viral haemorrhagic disease transmitted by infected Aedes mosquitoes.
Symptoms include fever, headache, jaundice (yellowing of the skin), muscle pain, nausea, vomiting and fatigue.
Some infected people may not experience any of these symptoms.
In severe cases, bleeding may occur from the mouth, nose, eyes or stomach.