5 Emerging Infectious Diseases to Watch in 2025

by Pavithra Mohan

As we move through 2025, public health experts around the world are closely monitoring several emerging infectious diseases that pose potential risks to global health. Understanding how these diseases spread and how to prevent them is key to preparing for—and hopefully preventing—future outbreaks. Here are five infectious threats currently making headlines:

1. Avian Influenza (H5N1)

Also known as “bird flu”, the H5N1 strain of the influenza A virus primarily infects birds, but it can occasionally infect humans and other animals. In 2024 and 2025, H5N1 has spread widely among wild and domestic bird populations, raising concerns about its pandemic potential. Notably, the virus was detected in dairy cattle in the United States and horses in Mongolia—an unusual and worrying development that suggests a broader host range.

Although human infections remain rare, they are often severe, with a high fatality rate. Vigilance is crucial: monitoring bird populations, practicing safe poultry handling and cooking, and advancing vaccine research are top priorities.

2. Measles

Once largely controlled through widespread vaccination, measles is resurging in multiple countries due to falling immunization rates. In 2025, regions such as Western Australia have reported outbreaks, with at least 12 confirmed cases since March. Public exposure occurred in places like pubs, supermarkets, and public transport hubs.

Measles is extremely contagious and can cause complications such as pneumonia, encephalitis, and even death, especially in young children and immunocompromised individuals. Maintaining high vaccination coverage is the most effective way to prevent outbreaks.

3. Japanese Encephalitis Virus (JEV)

JEV is a mosquito-borne virus found primarily in Asia and the Western Pacific. It can cause serious brain inflammation (encephalitis), with symptoms ranging from fever and headache to seizures, paralysis, and even death. In early 2025, health officials in Queensland, Australia, reported several confirmed cases, including fatalities.

Preventing JEV relies on mosquito control, personal protection (e.g., insect repellent, protective clothing), and vaccination in high-risk areas. Climate change and habitat expansion of mosquito vectors may increase the risk of future outbreaks.

4. Human Metapneumovirus (HMPV)

HMPV is a respiratory virus that often resembles the common cold but can lead to more serious illness—particularly in infants, older adults, and those with weakened immune systems. In late 2024, China experienced a surge in HMPV cases, accounting for more than 6% of respiratory infections tested.

Experts attribute the spike to reduced population immunity following COVID-19 restrictions and more comprehensive respiratory testing. There’s currently no vaccine or specific treatment, so good hygiene practices and supportive care remain the best defense.

5. Candida auris

Candida auris is a multidrug-resistant fungus that has emerged as a major global health concern. First identified in 2009, it has since spread across continents, primarily in healthcare settings, causing invasive infections with high mortality rates.

In 2025, Singapore reported the discovery of a new genetic clade of Candida auris, highlighting its rapid evolution and adaptability. It spreads easily in hospitals and can survive on surfaces for extended periods. Containing its spread requires rigorous infection control, heightened surveillance, and research into new antifungal therapies.

Conclusion

The world continues to face evolving infectious disease threats—from familiar foes like measles to emerging dangers like Candida auris. Strengthening global surveillance, ensuring vaccination coverage, promoting hygiene, and investing in rapid response capabilities are essential steps toward safeguarding global health. As we’ve learned from past pandemics, early action can save lives.