Pandemic vs. Epidemic

It might be surprising how off guard COVID-19 took the world. But there are some other illnesses, which are just as deadly, that have been neglected for years. What if the world had an outbreak of one of these?

Trying to establish a timeline of what has been COVID-19 pandemic, the 2011 film, Contagion shows the spread of a deadly virus by respiratory droplets. Social chaos, conspiracy theories and a race against the clock to find a vaccine. In a flashback, a bat infected a pig that was consumed at a dinner party.

Fast forward to December 2019, and a deadly virus spreads in Wuhan, China, the virus was identified to come from bats. Experts are still to determine how the virus jumped from bats to humans.

By 2020, the entire world was entering lockdown. Borders closed, isolation was mandatory or recommended and health professionals were struggling with patient care and space. Panic increased, and so did the confirmed cases and deaths. Like the plot of a horror movie, the advance of the virus made the entire world suffer.

COVID-19 is not the first virus to spook humanity, but it has been one of the most dangerous because of the highly contagious nature of the virus and its mortality rate. HIV- AIDS, which was first recognized as a disease in 1981, it had a death toll of 690,000 by 2019. In comparison, coronavirus had 743,487 deaths, reported to WHO as of the 13 of August 2020.

38,000,000 people are currently living with HIV, and as of the August 13 2020, there were 20,405,695 confirmed cases of COVID-19. For a virus that began spreading in November 2019, it has rapidly reached the numbers of a virus that has been around for significantly longer.

The main difference between these diseases is that HIVs spreads by sexual interaction or the exchange of blood. In contrast, coronavirus spreads quickly through respiratory droplets and contact routes. On the other hand, for both viruses, some patients can be carriers and transmitters whilst remaining asymptomatic. When this is combined with careless individuals, it becomes extremely hard to control.

Other deadly viruses

In 1897, Bram Stoker published a story about a bloodsucking monster carrying a curse and infecting his victims with vampirism. Although vampirism relies on fiction, there is a significant threat with smaller bloodsucking animals.

Mosquitoes are one of the deadliest animals in the world. According to National Geographic, there are over 3,000 species of mosquitoes, and three of them are responsible for millions of deaths worldwide every year. Mosquito-borne diseases are malaria, dengue, yellow fever, Zika virus or Chikungunya virus. These have been around the world for many years, and yet, there is no vaccine available.

According to WHO, more than half of the world´s population live in areas where the mosquito responsible for spreading dengue, yellow fever, Zika virus or Chikungunya lives. So why is there no cure for those, but there are three different COVID-19 vaccines already on trial phases?

Kelly Charniga, PHD student of infectious diseases and epidemiology at Imperial College London, has been working with vector transmitted diseases and epidemiology. “In terms of spread and deaths COVID is more dangerous, Zika rarely results in death, and 80% of patients have no symptoms, but on the other hand, you get diseases like dengue or yellow fever where there are bleeding and death.”

The WHO had registered 219,000,000 cases of malaria by 2017 and a death toll of 435,000 Dengue has an average of 100-400 million infections each year. Maybe the difference lies within is on the victims of each virus.

The demographics of the population at high-risk from COVID include older people, people with underlying health conditions and pregnant women. However, contrary to this, a mosquito bite does not discriminate and “Zika virus is considered mild, but it has serious complications, and in 1947 in Uganda, it killed newborns.” Added Charniga.

Then maybe is the way the virus has spread. In general, mosquito-related viruses have behaved similarly, or even worse than COVID-19. In December of 2019, the world was turning on the alarms of a new illness that was concerning China. A somehow rapid response. “When Zika was detected in Brazil, it was 2015, but we can now confirm it had arrived in 2013. This happens because the virus has similar symptoms of other viruses, which means Zika was circulating without us knowing,” said Charniga.

It is common with tropical viruses; they share symptoms which only complicates diagnosis and detection and, just like with social distancing, there are ways to prevent the spread of the virus. “At an individual level, it was advised to prevent mosquito bites by not travelling and to remove standing water at houses so mosquitoes cannot reproduce,” explained Charniga “the population used vector control, but there is still more research needed.”

Neglect

The delay comes from a geopolitical angle. Even when WHO says 80% of the world’s population is at risk of one or more vector-borne disease -which includes a wide range of insects- “These are neglected tropical diseases that appear and primarily affect low-middle income countries. Sadly, it means less funding, resources, and research,” said Charniga.

Like many other problems such as hunger, poverty and potable water, it is not a priority because it is not affecting the big economies. But now, tropical illness might start receiving the attention they need.

Charniga said in the near future “with climate change, mosquitoes are likely to move away from their current habitats, towards the poles. The US, and parts of Europe will receive these mosquitoes. There has already been evidence of invasive mosquitos in France that can carry the Chikungunya virus.”

A study published in Communications Biology supports Charingas´statement. The study reveals that the elevation of CO2 in the atmosphere promotes speciation in mosquitoes. The theory explains that higher temperatures reduce hatching times and increases survival rates. Temperature also changes migration patterns for other species which are hosts of numerous mosquitoes’ species.

The WHO reported in 2018, there were 18 cases of Zika virus in Germany, and by July 2019, 87 countries had active cases. For public health researches, this environmental change opened a new field to study, and a threat to the US or Europe means the possibility of a vaccine. “It takes affecting a high-income country for research to develop in that area. We might see that soon for Chikungunya,” said Charniga.

Could the next few years see significant medical breakthroughs? Will new outbreaks of vector-borne diseases finally incentivise us to find a vaccine? Is the world ready for a tropical disease pandemic?