Temple researchers explain link between climate change and disease

Our future may hold an increase of diseases coming from animals, like COVID-19, whose spread can be exacerbated by the effects of climate change.

Scientists warn that climate change can lead to diseases such as COVID-19 to become more frequent and spread more rapidly in the future. | JEREMY ELVAS / THE TEMPLE NEWS

It’s the beginning of April in 2050, but the days are already soaked with a heat that used to arrive in June several decades ago.

You swat yet another blood-swollen mosquito from your newspaper, and spray an extra layer of your medical-grade bug spray, thinking of how malaria cases in your city are growing by the day.

But what’s more pressing is the arrival of news you’ve been expecting: citizens are to prepare for the annual two week quarantine – a nationwide routine meant to keep the year’s diseases from getting out of hand. 

Although it sounds like science fiction, scientists studying climate change impacts warn that COVID-19 could be just the beginning of a pattern of increasingly frequent epidemics related to climate change, according to the World Economic Forum. Factors, like increased rainfall and temperatures associated with climate change, exacerbate disease by exposing more people to infection.

“It may be hypothetical to some policymakers, but it’s not really hypothetical to other scientists who study it,” said Kevin Henry, an environmental studies professor whose research focuses on disease mapping and health disparities. “We’ve seen that with this pandemic.”

Climate change is defined as a long-term change in weather patterns that define Earth’s climate, along with any effects it may have, according to NASA.

In March, the World Economic Forum released a report stating “epidemics will become more common with our increasingly connected age” as rapid growth in population and urbanization bring people into close contact. 

Infectious disease was named, by the same report, one of the top 10 risks the world will face in the next decade, with impacts expected to include approximately 250,000 additional deaths per year, according to the World Health Organization.

Nearly 75 percent of all new, emerging, or re-emerging diseases affecting humans at the beginning of the century were zoonotic, or coming from animals, The United States Agency for International Development reported in 2016

This includes diseases like the 2003 SARS outbreak, a strain of coronavirus, which resembles viruses found in bats and pangolins, according to a report from the Scripps Research Institute.

Small changes in the climate can cause large-scale shifts in the behavior and movement of animals, leading to more interactions and disease exposures with humans, said Shannon McGinnis, fourth-year epidemiology Ph.D. student. 

Yet Henry and Murphy believe that with climate change, the most significant disease risks may lie elsewhere — in water and vector-borne diseases, or diseases transmitted by organisms like mosquitoes and ticks, they said.

Scientists are able to use mathematical modeling to identify potential health risks, pathogens in the environment and vulnerable locations and populations, Murphy said.

The models Murphy uses predict cases of illness and infection based on different variables. In the case of COVID-19, the White House uses similar models that predict potential COVID-19 deaths to make policy decisions, NBC News reported.

“There’s certain people who tend to try to avoid using climate change because they think it will cause people to stop listening when they hear that term,” McGinnis said. “It opens up the door of all these different pathways that the disease can get into the environment that we maybe haven’t considered.”

In addition to increasing the risk of extreme weather events, like hurricanes and flooding, climate change can increase annual precipitation and the amount of moisture circulating in the atmosphere, which can lead to an increase in waterborne diseases, according to NASA.

Research by Murphy and McGinnis found an association between monthly cumulative rainfall and reported gastrointestinal diseases in Pennsylvania in the last five years. Precipitation leads to runoff from farms, and overflow of sewage into waterways that people then swim in or ingest and become ill. 

COVID-19 has been found in human sewage, which has the potential to get into waterways and create new pathways for infection, McGinnis said.

Philadelphia’s old infrastructure cannot handle the inundation of increased rainfall as its design combines stormwater pipes with sewage pipes, and if the capacity is exceeded, it overflows sewage into rivers like the Delaware and Schuylkill, the Environmental Protection Agency reported.

“Across the U.S., aging infrastructure is a huge problem, and climate change is not going to help with that,” Murphy said. 

When standing water accumulates, mosquitoes lay their eggs to hatch in or near standing water, according to the Center for Disease Control and Prevention. Mosquitoes are vectors of diseases like West-Nile Virus, malaria and Zika, and as cities like Philadelphia get warmer, the range of these mosquitoes spreads northwards, according to the National Center for Biotechnology. 

“For climate change and mosquitoes, certainly this is something to be alarmed about right now because it’s happening as we speak,” Henry said.

Forty-eight states in the U.S. experienced their fifth-warmest January on record this year, the Inquirer reported. Based on observed patterns of diseases, could lead to more mosquito related infections and a worse flu season, Henry said.

Despite having information about emerging disease patterns, more funding is needed to produce data to help implement corresponding policy. If this doesn’t happen, an outbreak of disease may be the only way to get any sort of funding, Henry said.

“You hate to say it, but it would take a West-Nile outbreak to have these cleanup campaigns, but it should never come to that, we should be being more proactive about that,” Henry said. “We go through these cycles of funding because we’re not being smart about the science that we have available to us.”

Addressing these effects would involve both mitigation, reducing greenhouse gas emissions to prevent climate change, and adaptation to environmental impacts and damages, Murphy said. 

Mitigation of mosquito-borne diseases includes public maintenance projects to reduce standing water and garbage pollution, Henry said. For water-borne diseases, prevention involves preparing stormwater systems for more extreme weather and implementing water-recycling networks, Murphy added.

Once diseases have a presence though, adaptations like widespread encouragement of vaccinations and education about disease, as well as constant epidemiology funding in order to identify how people are getting sick would be necessary to begin addressing outbreaks, said Henry.

“Health care is not just about being cured when you need to or being treated when you need to, but that whole preventative part that we ignore in the United States,” Henry said. 

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