Viruses All Over the World

Prof. Hervé Fleury, MD-PhD

University of Bordeaux, France & Ventum Biotech, Boston, USA

Here we list the viruses that have infected humans (regardless of the number of cases) on the different continents. Most of these viruses are dangerous and/or potentially associated with a future pandemic (Avian flu H5N1); we are not dealing here with viruses that are now well known and that circulate throughout the globe (seasonal influenza viruses, SARS CoV 2, HIV, viral hepatitis, etc.)

An animal disease: Chronic Wasting Disease (CWD) (see below) poses a real problem and the question of whether the prion responsible can be transmitted to humans.

North America

• Avian flu – H5N1

  • More than 70 human cases, mostly farmers, with one death (in Louisiana); a teenager from Toronto, Canada, infected with the H5N1 virus and presenting with ARDS (Acute Respiratory Distress Syndrome) survived.

  • Reservoir/Source: wild birds then flocks of poultry, cattle, farmers, cats, rats, and raw pet food

• Measles

  • 124 cases in Texas; First death in a child at the end of February 2025

• Chronic Wasting Disease (CWD)

  • Reservoir: deer (prion; transmissible to humans?)

• Mpox clade 1b

  • A few cases, imported from Africa (see below)

Picture CIDRAP – Deer

Picture CIDRAP – Mpox clade 1b

Africa

• Mpox clade 1b

  • Congo DR

    • Source: sex workers and then general population

    • Reservoir: rodents, squirrels

    • Transmission by direct contact or aerosols from the reservoir, and then human-to-human transmission by direct contact (including sexual contact)

• Ebola

  • Uganda

    • Reservoir: bats

    • Intermediate host: monkey

• Marburg

  • Tanzaniao, Rwanda, Equatorial Guinea

    • Reservoir: bats

    • Intermediate host: monkey

Picture CIDRAP – Ebola

South America

• Oropouche (Arbovirus)

  • Brazil, Bolivia, Colombia, Peru, Cuba, French Guiana

    • Reservoir: sloth

    • Transmission: midges

• Dengue (Arbovirus)

  • Brazil

    • Reservoir: mainly monkeys and then humans

    • Transmission: mosquitoes

Dengue expanding globally as shown in this WHO map

• Chapare (Arenavirus)

  • Bolivia, La Paz

    • Reservoir: rodents

    • Transmission to human by aerosol or direct contact

• Western equine encephalitis (Arbovirus)

  • Argentina

    • Reservoir: Birds

    • Transmission to horses and humans by mosquitoes

Asia

• Avian flu H9N2

  • China, Vietnam

• Avian flu H5N1

  • Cambodia

• Poliovirus cVDPV2

  • Indonesia (below)

• Nipah

  • Bangladesh, India

    • Reservoir: bats

    • Transmission by direct contact or palm juice contaminated with the urine of infected bats

• Zika (Arbovirus)

  • India (Maharashtra)

    • Reservoir: monkeys, then humans

    • Transmission: mosquitoes

Middle East

• MERS-CoV

  • Saudi Arabia

    • Reservoir: bats

    • Intermediate host: camel

It is important to note the circulation of poliomyelitis viruses in two cases: wild polio virus type 1 (WPV1), which has resumed circulation in recent years in Pakistan and Afghanistan; live vaccine virus (circulating poliovirus type 2 derived from a vaccine strain: cVDPV2) which has regained its pathogenicity and has induced cases of poliomyelitis in Niger, Benin, Chad, Guinea, Nigeria, Somalia, Sudan, Algeria, Yemen, Indonesia. In 2022, the United States experienced a case of cVDPV2 poliomyelitis in a New York subject who had not been vaccinated. Molecular studies in wastewater from different countries (USA, UK) have confirmed the circulation of this virus.

References

WHO: Emerging Diseases

CIDRAP, University of Minnesota

Fleury HJA; Emerging and Re-emerging Viruses, Elsevier/Masson publisher 2023