Deadly disease spread by blood-sucking insect ‘could erupt into pandemic’ say scientists

A deadly disease spread by mosquitoes could cause a global pandemic that would make the "Covid-19 pandemic pale by comparison", scientists have warned. Yellow fever (YF) is a serious viral infection that is transmitted to humans by the bites of infected mosquitoes.

Scientists say the infectious disease that can result in fatalities has spread due to urban growth and increased travel. A recent study published in the journal npj Viruses said: “Unlike other mosquito-borne diseases, humans infected with YFV exhibit heightened viremia and are efficiently amplifying hosts, allowing for inter-human transmission by mosquitoes.

“This makes YFV particularly capable of sparking urban epidemics, as infected people can efficiently infect mosquitoes that bite them.”

The international group of scientists added that while yellow fever has not yet been transmitted to the Asia-Pacific region the risk is higher than ever with studies suggesting an “expansion”.

The paper states: "A YF pandemic in today’s world would cause a devastating public health crisis that, because of the much higher lethality, would make the Covid-19 pandemic pale by comparison."

The study’s authors added: “The concern that YFV will spread to the Asia Pacific region that Carter raised 100 years ago in his treatise on the subject remains equally pressing today.

"Indeed, we would argue that the likelihood of such a catastrophe could be even higher now than it was in Carter’s time."

Initial symptoms of yellow fever appear three-six days after exposure. Symptoms include fever, headache, muscle pain, nausea, and vomiting. However, in severe cases, the disease can cause jaundice (yellowing of the skin and eyes), dark urine, abdominal pain, and bleeding. 

Bleeding can also occur from the mouth, nose, eyes, or stomach, WHO warns that about 15% of people will enter this stage.

Half of the patients who enter the "toxic phase" die within seven-10 days, WHO figures suggest.

The virus is not spread from person-to-person through coughing, sneezing, or touching. In forested areas, yellow fever virus primarily circulates between forest-dwelling mosquitoes and non-human primates, such as monkeys. 

Yellow fever is believed to infect around 200,000 people each year and to kill 30,000 of them.

Vaccination is the best way of preventing yellow fever. The vaccine provides immunity within 10 days for 80–100% of people vaccinated, and within 30 days for more than 99% of people vaccinated.