From COVID to Hantavirus: Why disease outbreaks are becoming more frequent worldwide

From COVID-19 and mpox to Ebola, Zika and the recent hantavirus outbreak linked to cruise passengers travelling across multiple countries, the world has witnessed an unusual rise in infectious disease outbreaks over the past decade.

Public health experts say the increase is not accidental. Rapid urbanisation, climate change, global travel and growing human contact with wildlife are creating ideal conditions for pathogens to spread faster and farther than before. 

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According to the World Health Organization (WHO), nearly 60% of emerging infectious diseases originate in animals, while around 75% of newly emerging pathogens are zoonotic — meaning they jump from animals to humans. 

Major disease outbreaks in the last decade 

COVID-19 (2019 onwards): The coronavirus pandemic remains the most devastating outbreak of the modern era. First detected in China in late 2019, COVID-19 spread globally within months and caused millions of deaths, overwhelming healthcare systems and disrupting economies worldwide. 

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Ebola outbreaks (West Africa and Congo): Ebola outbreaks repeatedly hit African nations during the past decade, especially the Democratic Republic of Congo and West Africa. The virus, which spreads through bodily fluids, recorded high fatality rates and exposed weaknesses in public health surveillance systems. 

Zika virus outbreak (2015-16): The mosquito-borne Zika virus spread rapidly across the Americas and triggered global alarm after scientists linked infections in pregnant women to birth defects such as microcephaly. 

Mpox outbreak (2022 onwards): Mpox, formerly known as monkeypox, spread to dozens of countries in 2022. WHO later declared it a global public health emergency as cases emerged across Europe, the Americas and Asia. 

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Hantavirus outbreak linked to cruise travel (2026): A recent hantavirus outbreak connected to cruise passengers travelling aboard the MV Hondius triggered international monitoring efforts after confirmed infections were reported across multiple countries. Health agencies tracked passengers and contacts as concerns grew over cross-border transmission. Though hantavirus does not spread as easily as COVID-19, the outbreak highlighted how quickly infectious diseases can spark global concern in an interconnected world. 

Bird flu and swine flu scares: Recurring outbreaks of avian influenza strains such as H5N1 and H7N9, along with swine flu variants, have kept health agencies on alert because of fears that these viruses could mutate and trigger future pandemics. 

Dengue surges across tropical regions: Several countries in Asia, Latin America and the Caribbean have recorded record dengue outbreaks in recent years, with scientists linking the rise to warmer temperatures and changing rainfall patterns that help mosquitoes breed faster. 

Why are outbreaks becoming more frequent? 

Climate change is expanding disease zones: Rising global temperatures are allowing mosquitoes, ticks and other disease carriers to survive in regions that were previously too cold. WHO says climate change is altering the distribution of vectors responsible for diseases such as dengue, malaria and Lyme disease. 

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Infectious diseases are also becoming harder to control because floods, droughts and heatwaves damage sanitation systems and displace populations, increasing the risk of outbreaks. 

Humans are coming into closer contact with wildlife: Deforestation, mining, agriculture and urban expansion are shrinking natural habitats and forcing animals closer to human populations. Scientists say this increases the chances of viruses crossing species barriers. 

WHO estimates that more than 30 new human pathogens have been detected in the last three decades, with most originating in animals. 

Global travel spreads diseases faster 

Modern travel allows infected individuals to move across continents within hours. Diseases that may once have remained localised can now spread internationally before symptoms are even detected. 

COVID-19 and the recent hantavirus-linked cruise outbreak demonstrated how quickly health alerts can escalate in an interconnected world. 

Rapid urbanisation and overcrowding 

Mega cities with dense populations create ideal conditions for disease transmission. Inadequate sanitation, poor waste management and overcrowded housing can accelerate the spread of infections, especially in developing nations. 

Overuse of antibiotics in humans and livestock is making many infections harder to treat. WHO has repeatedly warned that antimicrobial resistance could become one of the biggest global health threats of the century. 

What experts fear next 

Scientists increasingly warn that future outbreaks may become more common unless countries strengthen surveillance systems, protect ecosystems and improve global cooperation on public health. Several studies suggest zoonotic spillover events are rising steadily each year. 

The WHO and United Nations now promote the “One Health” approach, which recognises that human, animal and environmental health are deeply interconnected. Experts say outbreaks are no longer rare “once-in-a-generation” events. Climate pressures, ecological disruption and global connectivity have fundamentally changed how diseases emerge and spread.