If there is one thing that COVID made us aware of, it is the devastating impact that diseases and viruses can have on our daily lives. Every day, we face the resurgence of infections that were once under control as well as the rise of previously unknown threats. As we have learned, these diseases don’t just surface in far-flung areas of our globe but have the ability to hit much closer to home. In this article, we will take a look at the 11 deadliest diseases currently facing our species.
Bird Flu
Bird flu not only affects birds, but also has the potential to infect many other species, including humans. In fact, researchers have found asymptomatic cases in equine species, which has raised considerable concerns about hidden transmission of the virus. The first death in the US was linked to poultry exposure and occurred in Louisiana. While widespread human-to-human transmission hasn’t happened yet, it is still has the potential to grow into a pandemic.
Antimicrobial-Resistant Bacteria
Antimicrobial resistance (AMR) is a global crisis growing at a worrying rate. Drug-resistant infections cause 1.27 million deaths every single year. WHO and CDC have both brought attention to the threat that AMRs pose to public health. They have called for responsible antibiotic use and global collaboration. Efforts to combat this global health issue include reducing AMR deaths by 10% by 2030. They are also working on developing five new treatments by 2025 through the Global Antibiotic Research & Development Partnership.
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Cholera
Cholera has been considered a global health issue for quite some time. Cholera is caused by contaminated food or water and continues to be a global health problem, with up to 4 million cases reported annually. In 2024 alone, 28 countries documented 371,517 cases with 2,527 deaths, making it potentially among the deadliest diseases in 2025. Displacement, natural disasters, and climate change all help to contribute to the spread of outbreaks. Worryingly, despite increased vaccine production, shortages still persist. The GTFCC’s “Roadmap 2030” intends to reduce cholera deaths globally by 90%.
Chikungunya
Chikungunya is another one of the potentially deadliest diseases to look out for in 2025. This is a disease that is spread by Aedes mosquitoes. The symptoms include severe joint pain and fever and can last from months to years in extreme cases. More than 480,000 cases and 200 deaths were reported around the world in 2024. All is not lost though, with a new vaccine being approved by the U.S., and there is currently a large study tracking its impact taking place in East Africa. Chikungunya also increases one’s risk of developing arthritis, making its prevention a top priority.
COVID
COVID-19, which remains a global issue in 2025, has now developed into the extremely transmissible Omicron subvariant XEC. Not surprisingly, it is still considered among the most potentially deadliest disease. Vaccines still continue to be helpful against adverse outcomes, and health officials recommend that everyone aged six months and up get current vaccines. The JCVI continues to do research on the virus’s development, and COVID-19 vaccines are now included in normal cost-effectiveness studies alongside regular immunization.
Dengue Fever
Dengue fever is on the rise worldwide, with over 7.6 million cases and 3,000 deaths confirmed by April 2024. The Americas have been particularly affected in recent years. A new dengue vaccine, TAK-003, has recently been authorized for use in children in high-risk locations. Despite improvements, the rising number of cases demands improved tracking, mosquito control, and public awareness to effectively combat the worldwide outbreak.
Measles
Believe it or not, measles is actually making a comeback, with global cases reaching 20% between 2022 and 2023 due to decreased vaccination rates. Coverage dropped during the epidemic, reaching its lowest point since 2008. Since then, Europe reported a 45-fold increase in cases, while the United Kingdom declared it a “national incident.” Health experts have begun to emphasize the importance of increasing vaccination efforts to avoid future outbreaks in the public at large. However, with so many people now considering themselves “anti-vaccine”, this problem might not go away anytime soon.
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Disease X
Disease X sounds like something from a science fiction movie, yet this hypothetical disease has an actual purpose. It is a placeholder for any potential disease that may arise. The World Health Organization’s “Disease X” concept highlights the importance of being prepared for unexpected health threats. COVID-19 brought this concept to life, demonstrating the significance of studying entire viral families. In late 2024, an epidemic in the Congo, previously known as Disease X, killed 79 people before being diagnosed as a deadly malaria strain.
Scabies
Scabies instances in the UK have increased dramatically, with rates tripling in recent years, especially in the northern England region. This extremely contagious skin illness spreads by intimate contact, resulting in severe itching and redness. Typically, topical creams and oral ivermectin are used to treat the condition. To effectively control outbreaks, health officials stress early detection and treating all close connections, including those who are asymptomatic.
West Nile Fever
West Nile Fever incidences are increasing rapidly in Europe, with 1,436 infections documented in 2024, nearly doubling the number from 2023. Greece, Italy, Spain, and Hungary have been the hardest hit. While the majority of infections are asymptomatic, serious complications such as encephalitis are uncommon but could be fatal. This underscores the need for better understanding and prevention of this deadly mosquito-borne illness.
Whooping Cough
Whooping cough is also making a resurgence lately as one of the deadliest diseases. In fact, Australia confirmed the highest number of cases in 2024 than any year previously recorded. Infants under six months of age are in the greatest danger. Once again, declining vaccination rates are a major factor, with many people failing to get their booster shots. Health experts recommend immunizations, including Tdap, for pregnant women and caregivers to protect babies and limit the spread of whooping cough.