/ 9 September 2023

Climate change, deforestation fuel virus outbreaks

Global Climate Strike Outside Parliament In Cape Town
It is important that we all have the same goal: a climate-neutral and resilient future in which our children can live in security and prosperity. Photo: Brenton Geach/Gallo Images

Climate change and deforestation are the primary culprits behind the alarming increase in global outbreaks of viruses such as dengue fever, Zika and chikungunya.

Speaking at a side event during Africa Climate Week in Nairobi, Kenya this week, Samuel Kariuki, the Eastern Africa director for the Drugs for Neglected Diseases Initiative, said environmental changes are acting as catalysts, facilitating the expansion of infectious diseases which threaten populations worldwide.

He said climate change is not just a concern for environmentalists but a risk to public health that demands immediate action. It has become a driving force behind the proliferation of infectious diseases.

“The climate crisis is a massive threat to global health. We’re at Africa Climate Week to sound the alarm about the impact of climate change on neglected diseases and the urgent need for better treatments. It’s time for action,” urged Kariuki.

“Changes in temperature, precipitation patterns and the distribution of disease vectors, like mosquitoes and sandflies, are amplifying the reach of these pathogens,” he said.

Kariuki highlighted the vital role that public awareness and education about the control of infectious diseases play in addressing this growing crisis: “In the battle against both climate change and infectious diseases, knowledge is important.”

He said the flies and mosquitoes responsible for spreading diseases such as chikungunya and dengue fever have received insufficient attention on the global stage. Weather conditions cause these species to spread and climate change causes people to move into areas where they are rife.

“For instance, dengue fever has witnessed an alarming 85% increase in cases over the past half-century. Currently, half of the world’s population is at risk of contracting this debilitating disease. Recent outbreaks in Sudan, European countries, Peru and parts of the Kenyan coast have underscored the global nature of the problem,” he said.

The World Health Organisation (WHO) corroborated these concerns in a report released in April. The incidence of mosquito-borne illnesses has seen a dramatic surge in recent decades: “Dengue cases skyrocketed from just over half a million globally in the year 2000 to a staggering 5.2 million in 2019,” it found.

The report added climate-induced events, such as floods and droughts, played a significant role in displacing communities and bringing them into contact with infected sandflies and mosquitoes, sparking disease outbreaks.

Kariuki said it was important for governments to address visceral leishmaniasis, a neglected disease spread by sandfly bites, which is the largest parasitic killer after malaria.

Climate change exacerbates poverty by eroding livelihoods and diminishing access to food and clean water, making people vulnerable to disease.

Ahmed Ogwell Ouma, acting deputy director general of Africa Centres for Disease Control and Prevention, echoed Kariuki’s concerns. 

“Climate change threatens to undo decades of progress in controlling these diseases and exacerbates existing health inequalities.

“We must bring the health agenda to the discussions of our climate summit, not just at the continental level, but also globally. We’ve been talking for 30 years; now it’s time for action.”

Ouma said it was important to integrate medical innovation into climate change adaptation strategies. 

“This is particularly crucial in Africa, where the shortage of effective diagnostics, drugs and vaccines for climate-sensitive, neglected diseases is particularly acute,” he said.

The WHO had identified 45 countries at risk for these diseases, with 23 of them in Africa.

“Agriculture, health, and development are all suffering due to climate change. Bringing health discussions to the climate change platform is essential for Africa,” Ouma said.

He called on leaders to use the UN Climate Change Conference (COP28), to be held in Dubai in the United Arab Emirates starting at the end of November, to recognise neglected diseases before they become a crisis.

“The African continent has been discussing climate change for over three decades. It should remain a priority at COP28.”

He explained that climate change has directly affected health, leading to the emergence of diseases such as Ebola and Marburg. 

“We have diseases that come about as a result of disruption in the animal system, for example, drought, then you end up with yellow fever … We have the emerging diseases, Ebola, you have Marburg disease, that were not really within the human population before but because we are disrupting the environment, then they come into the population,” he said.

During the session, vector-borne disease epidemiologist Judy Omumbo said there was a need for African states to find solutions to the emerging health crises.

Omumbo criticised African leaders for failing to prioritise health in discussions on climate change and development. She pointed out that this oversight strains healthcare systems and exacerbates health disparities.

“When we think about development, we often focus on GDP, energy and agricultural innovation but we neglect to address the well-being of people and the survival of species,” Omumbo said.

She called for greater involvement of health experts and researchers in policymaking to ensure effective action. 

“We must insist health experts have a central role in collaboration. We need health experts at the heart of policymaking. I want to understand why agriculture is prioritised over health.”

Mandisa Nyathi is a climate reporting fellow, funded by the Open Society Foundation for South Africa.