Dr Rotimi Adesanya, a public health physician in this interview with The Punch talked about yellow fever disease. According to him, yellow fever is also transmitted through mosquito bites, but unlike malaria, yellow fever can be transmitted through infected Aedes mosquitoes. Read the excerpt below
What is yellow fever?
Yellow fever, like Ebola, is a viral haemorrhagic disease. It is a fever that causes bleeding from the holes like noses, ears, eyes and others called the orifice in medical parlance.
How does one contract yellow fever?
Yellow fever, like malaria, is usually transmitted through mosquitoes. The only difference is that malaria is transmitted through Anopheles mosquitoes while yellow fever is transferred from infected Aedes mosquito. The Aedes mosquitoes are common in the eastern parts (of the country) or places close to the forest. In the urban areas, we have the Anopheles mosquitoes, but the Aedes is common in tropical areas.
What are the symptoms of the disease?
Just like the name, fever is one of the symptoms of the disease. We also have jaundice, the yellowness of the eyes. Other symptoms are headache, muscle ache, joint pain, back pain, loss of appetite, shivering, nausea, vomiting and fatigue.
How is yellow fever diagnosed?
I mentioned earlier that it is a haemorrhagic disease; so, bleeding from the nose is one of the ways to diagnose it. Like Ebola, when people have Ebola, they bleed from the nose, ears, mouth and eyes.
Is bleeding from the nose linked to yellow fever?
It may not necessarily be yellow fever; it’s just that like if a person has a headache, there are many conditions linked to headache. It could be as a result of malaria or high blood pressure and other things. So, bleeding from the nose might not necessarily be from yellow fever. It might be from the weather and all that. But it is a good pointer to yellow fever but that doesn’t mean that anybody bleeding from the nose has yellow fever.
In all, the symptoms are indications that a person has the fever. To be on the safe side, it is wise to go to the hospital once one notices the symptoms.
What is the mortality rate of the disease?
It is a very mortal disease; it can lead to death if it is not properly taken care of. Presently, there is no cure for yellow fever. Once a person is affected, the person becomes weak because it affects the immunity of the person. Immediately yellow fever patients are brought to the hospital, we quickly resuscitate them by giving them drip, oxygen and make sure we maintain their blood pressure. In some cases, we do blood transfusion because they would have lost blood due to bleeding. There are also some bad cases that their kidney would have been affected and they would need dialysis.
That indicates how bad the disease can be. It is a mortal disease that should be properly handled.
How can it be prevented?
It is prevented like we prevent malaria because the mode of transmission is the same – mosquito bites. One should make sure that the environment is clean; bushes are cleared to prevent hideouts for mosquitoes. The use of insecticide-treated nets should also be encouraged by people. People should also take the issue of vaccination seriously. Unlike malaria that has no vaccination, yellow fever has and people should ensure that they take the vaccination.
How effective is the yellow fever vaccine?
The vaccine is very effective and the more people are researching, the better the vaccine is. In the past, people were given the anti-yellow fever vaccine every 10 years but now it is once and for all. A single dose is enough for a lifetime.
In Nigeria, every child is given the vaccination at nine months and it is supposed to protect them for life from yellow fever. Under the National Programme on Immunisation, we give only two vaccines to nine-month-olds – the anti-yellow fever vaccine and the anti-measles vaccine.
Is the vaccine safe for everybody?
Generally, there are people who should not take vaccination irrespective of what it is. There are some people who are not candidates of vaccination. The way vaccine works is that you give people so that the body produces antibodies. But there are people we don’t give; for instance, people who are seriously ill and those with HIV because they don’t have immunity. We are also very careful when giving immunisation to pregnant women; we try as much as possible not to give vaccine to them.
Is a person free from yellow fever immediately after taking the vaccine?
Basically, the vaccine is to prevent the disease, but there are other factors responsible for one getting the disease. For example, if a person is bitten by an infected mosquito; if the person has immunity or is ill, the person might get infected. When people have taken the vaccine, and they get infected, it would not be as bad as those not vaccinated. For example, children get vaccines for measles but some still come down under the disease but it would not kill them or affect them terribly like those who were not been vaccinated.
Does the yellow fever vaccine have side effects?
Generally, when people take vaccine, they could have an allergy or a little fever but it is temporary. In a matter of a few hours, it would be gone.
What is your advice on ways to curb the spread of the disease?
Due to the recent cases of the disease in the country, one needs to educate people in order to curb the disease. What I will advice is that people should keep their environment clean; they should get rid of stagnant water which might cause the breeding of mosquitoes. They should make use of treated insecticide nets; lock their windows and doors to prevent mosquitoes from entering their houses. Those who have yet been immunised should get the vaccine. It is free and available in every public health centre. Those who didn’t get it as children can still get it as adults.