By Molly Cavanaugh, June 2026

Covid, hantavirus, and Ebola are all emerging viruses. Emerging viruses are viruses which have either just appeared or are suddenly posing a bigger threat (1). Hantavirus made the news recently when a cruise ship was infected with the virus (Article- How Far Can the Hantavirus Outbreak Go) . While the hantavirus infection remains contained, with no cases which did not originate on the cruise ship, it is only the latest in the  trend of emerging viruses (2). Ebola is currently raging across the Democratic Republic of the Congo (DRC). Why are so many emerging viruses emerging now and what can we do?

Ebola first appeared in 1976 in the DRC. The first outbreak had a very high mortality rate, with 280 deaths out of 318 confirmed cases (3). Since then, 6 different strains of Ebola have appeared, 4 of which cause disease in humans (4). Strains are variants on a virus that have different death rates or symptoms due to mutations in the genetic code but are still the same virus. Ebola Zaire, named after the first Ebola outbreak in the DRC, has the highest known Ebola death rate, ranging from 60-90% (5). The current Ebola outbreak is a rare strain known as Bundibugyo virus disease, causing only 2 outbreaks before 2026 (6). The two previous outbreaks, in 2007 and 2012 had a 30% and a 50% death rate, respectively, which is lower than Ebola Zaire but still extremely high for any outbreak (7). The largest Ebola outbreak, the Ebola Zaire stain, spanned from 2014-2016 (8.) That outbreak killed over 11,000 people and infected more than 28,000 (9). While the mortality rate was lower than the 1976 Ebola Zaire outbreak, the death toll remains the largest of any Ebola outbreak. The current outbreak is the Bundibugyo strain of Ebola. As of the date of this blog, the current outbreak in the DRC stands at 635 confirmed deaths and 127 deaths. This outbreak already represents the 3^rd largest outbreak in the history of Ebola (10).  More Ebola outbreaks are popping up all the time (11). So, what is causing an increase in outbreaks?

 Three factors contribute to the increase in emerging viruses: viral factors, human factors, and ecological factors (12). Viral factors include mutation within the virus that allows the virus to get better at causing infections, resulting in the virus itself causing the increase in outbreaks. Human factors are the factors that we directly control, like cutting down trees or an increase in hunting. Ecological factors are things like climate change or weather patterns. Both human and ecological factors tend to cause more interaction between natural reservoirs (a natural reservoir is an animal that carries a virus but stays healthy – also called a “host”) or infected animals and people, allowing for more infection opportunities. In the case of Ebola, the host is unknown, despite numerous large scale studies (13). Scientists caught bats with antibodies against Ebola, showing they were once infected with Ebola, leading to the hypothesis that fruit bats are the host, but this has not been confirmed. No matter what the host turns out to be, it is known that it is a wild animal, which means that all 3 of the different reasons could be contributing to the increase in outbreaks.

Viruses with multiple strains are harder to combat because doctors often need to have different treatments for the different strains. Ebola has 4 different pathogenic strains, which makes the virus harder to fight. While there are now treatments against Ebola Zaire, the Bundibugyo strain is rare; therefore, none of the cure or treatment strategies for Ebola have been approved for this strain (14). Similarly, the hantavirus outbreak of 2026 was only the 2nd hantavirus outbreak to ever be spread person to person (15). A rare virus can always be dangerous because scientists know less about it and can less easily predict how the outbreak will go. Humans can do little about the evolution of viruses except to evolve along with them. Now that we know the threat of person-person hantavirus spread and that the Bundibugyo strain is crawling out of the forest, where all the possible hosts live, we need to put the time and money into researching them.

Ecological factors might also be at play here. Studies have shown that environmental changes, such as droughts can cause wildlife like bats to venture further into human settlements or migrate to new places (16). A 2019 paper used disease information from previous Ebola outbreaks to predict how ecological and socioeconomic factors would influence Ebola outbreaks in the future (17). This paper concluded that the increase in greenhouse gasses will result in more Ebola outbreaks by impacting host habits or changing weather patterns. Another paper from 2025 examined how climate change increased rain fall which can lead to the increase of food available for the presumed hosts of Ebola, which will lead to more animals and more possibilities for Ebola to transfer to people (18). While ecological factors are an essential part of the puzzle, human factors play a bigger role in emerging virus outbreaks.

Human factors are at the center of the emerging Ebola outbreak. Ebola is spread by coming into contact with infected body fluids, like contaminated blood touching a cut or getting into your eyes (19).  Deforestation, expanding human populations, hunting bushmeat (wild animals ranging from rats to apes) for food, and person to person contact through care-giving or funerals all contribute to Ebola outbreaks (20, (21). In addition, modern transportation gives emerging viruses more opportunities to travel than ever before. For example, in the recent hantavirus outbreak, the virus never could have moved beyond the Andes without human help. In that case, the outbreak started when a man went bird watching in a dump, exposing him to an animal carrying the virus. The outbreak continued and expanded through modern transportation – a cruise ship full of people in extremely close corridors (21). Human factors also both helped and hurt in the Covid outbreak, with quarantining and mask helping to reduce the spread but human overcrowding allowed the virus to explode (22). Human factors are ones that we can work together to address.

The current Ebola outbreak also faces one distinct human problem that did not exist in the previous outbreaks: the disruption of USAID (23). The United States Agency for International Development began in 1961 to “support economic growth, combat the spread of disease, promote democratic reform, and address food insecurity.” (24). This organization helped established soft American power, the idea of gaining international power through persuasion or helping others instead of by force (25) . It also contributed to saving nearly 92 million lives just from 2001-2021 through vaccinations, outbreak containment, feeding the poor, education, and other programs. All while being less than 1% of the American budget (26, 27). Infectious disease anywhere is a problem everywhere and reducing safeguards like USAID will cause infectious disease to rise worldwide. USAID did not seek to reduce disease abroad just for power over other countries, but also to ensure that disease did not reach our borders (28). In previous Ebola outbreaks, USAID was essential to establish treatment centers, provide healthcare workers, and keep the outbreak contained (29). In fact, in 2018, the USAID even cited the 2014-2016 Ebola outbreak as the case to prove the need for an international response team for outbreaks (30). With the current gap in public health aid in West Africa, the former director of the Emerging Pandemic Threats program at USAID is expressing extreme concern on how the outbreak will be stopped without USAID (31).

Emerging diseases are scary, but we can do something about them. America must re-invest in public health and research. The United States withdrew from the World Health Organization (WHO) officially in January of 2026 and left 278 million dollars of fees unpaid (32). Now, the WHO is struggling to contain outbreaks around the world without one of the world’s biggest countries and with an unexpected debt. And the issues exist on a national level too. Between 2025 and 2026, the National Institute of Allergy and Infectious Diseases reduced funding for emerging infectious diseases by 36% (33, 34). Grant funding in the US has significantly slowed and less and less money is being awarded to study infectious disease (35). We can also reduce emerging diseases through education programs and collaborations with those people living in areas at risk for outbreaks (36, 37). Communication, relationships, and funding to study and treat emerging diseases are all essential to reducing future outbreaks (38).

Emerging viruses will continue to grow stronger and infect more people if we do not fight against them. In today’s global world, an Ebola outbreak in West Africa could spread across the world on international flights (39). We have been lucky that the hantavirus outbreak did not spread past the cruise ship, but we may not get as lucky every time. To combat viral factors, we need continuous research so we can evolve with the virus. To combat environmental factors, we need workers on the ground ready to fight constantly changing challenges. And to combat human factors, we need doctors, health organizations, governments, and local communities to work together to reduce human to human spread and to reduce the overlap of human activity and wild animal activity. We can work together to reduce future outbreaks of all emerging viruses.