THE 15 VIRUSES THAT KEEP THE PLANET UNDER SURVEILLANCE. FROM BIRD FLU AND NIPAH TO EBOLA AND THE ''SILENT PANDEMICS'' TRANSMITTED THROUGH MOSQUITOES - Filenews 24/5 by Marilena Panayi
The planet may have left behind the most dramatic period of the modern era, the period of the COVID-19 pandemic and the harsh restrictive measures, but health uncertainty has not only not subsided, but seems to be becoming more and more complex and unpredictable every year.
The World Health Organization, the European Center for Infection Control, the American CDC, but also all the other international and national public health organizations, have been stressing for some time that we are now in a state of permanent epidemiological surveillance, pointing out that several different viruses appear simultaneously in many regions of the planet, mutate, change geographical behaviour or are transferred from animals to humans with ways that until a few years ago were considered rare or even unlikely, in some cases.
The great concern, as recorded in dozens of official announcements of the last three years, does not only concern the visible possibility of a new pandemic, but the fact that for the first time in decades there are simultaneous outbreaks of different infectious diseases in different regions of the planet, while documented, diseases that were considered obsolete, have begun to appear again.
This new reality is attributed by the international scientific community to several factors or more correctly, to a combination of factors such as, among others, climate change, deforestation, urbanization, intensive livestock farming and population movement/migration.
Experts also point out that the experience of the COVID-19 pandemic has now made health authorities much more aggressive in monitoring any virus that shows increased contagiousness or unusual behaviour. The goal now is not only to deal with an epidemic, but to prevent it in time before it acquires international dimensions.
For 2026, a total of 15 different viruses and infectious diseases are under the microscope of scientists, some of which are of particular concern either because of their high mortality or because of the possibility of causing major international epidemics
H5N1: The prevailing scenario for a new pandemic
H5N1, that is, bird flu, has been causing serious epidemics in birds for years, but it has now been documented that it has passed to more and more species of mammals.
The latest data are of particular concern, as H5N1 has been detected not only in wild animals and birds, but also in dairy cows, cats and marine mammals.
Experts even argue that the more the virus circulates in mammals, the more likely it is to acquire mutations that will facilitate its transmission between humans.
To date, human cases have been recorded in Asia, while in the United States infections in cows are considered an extremely important development.
The WHO continues to consider H5N1 one of the most important "priority viruses" worldwide due to the high mortality it has in confirmed human cases, while scientists remind that historically major influenza pandemics started with animal viruses that acquired the ability to transmit from human to human.
COVID-19 MERS – CoV
Despite the fact that COVID-19 no longer dominates the news every day, SARS-CoV-2 is still circulating worldwide and mutating.
International organizations continue to monitor new variants, possible immune escape and the phenomenon of long COVID, which remains a major public health problem.
Experts now believe that COVID-19 has entered an endemic phase, but it continues to burden health systems and cause serious complications in elderly and vulnerable populations.
At the same time, MERS-CoV, the coronavirus that first appeared in the Middle East and is still considered one of the most dangerous coronaviruses worldwide, is also being closely monitored.
Although SARS-CoV-2 has dominated the global news in recent years, MERS has never disappeared and continues to cause periodic incidents, mainly in Middle Eastern countries.
MERS-CoV is primarily transmitted from camels to humans, but it can also cause limited chains of human transmission, particularly in an in-hospital setting.
Particularly worrying is the extremely high mortality of the virus compared to other coronaviruses. Experts consider that MERS remains one of the coronaviruses with the highest theoretical pandemic potential after SARS-CoV-2, mainly because it continues to circulate in animal populations and appear, intermittently, in humans.
Huge concern about the Nipah virus
In Asia, one of the viruses that still causes the greatest concern among scientists is the Nipah virus. The WHO consistently ranks it among the most dangerous viruses on the planet due to its combination of high mortality, transmission between humans and the absence of a treatment or vaccine.
Nipah is mainly transmitted by fruit bats, but it can also be passed from human to human through close contact and respiratory secretions.
Mortality in recorded outbreaks usually ranges from 40% to 75% (depending on the strain), while the virus causes severe encephalitis, neurological deterioration and coma.
The virus has returned to the center of international attention, following the recent outbreaks in India and Bangladesh, as it is considered one of the viruses with the highest theoretical pandemic potential. The great concern concerns the possibility that such a deadly virus will acquire more effective human-to-human transmission in the future.
Ebola Marburg
The director-general of the World Health Organization said he was "deeply concerned by the scale and speed" of the Ebola (Ebola) epidemic affecting the Democratic Republic of Congo and Uganda. The African Union Health Agency (Africa CDC) has declared a state of emergency at the African continent level for the Ebola Bundibugyo strain outbreak.
The declaration of a state of emergency will allow "the strengthening of regional coordination, the rapid activation of financial and technical resources, the strengthening of surveillance systems and laboratory activities", according to the Africa CDC.
Ebola causes highly contagious haemorrhagic fever. The virus has caused more than 15,000 deaths in Africa over the past 50 years. During previous peaks of the epidemic, mortality has fluctuated between 25% and 90%, according to World Health Organization data.
There are no approved vaccines or treatments for the Bundibugyo strain of Ebola, which causes death in 40% to 50% of cases. However, there is a vaccine called Ervebo, developed by Merck, that has been used for the Zaire strain and has shown to provide some degree of protection in animal testing.
According to the latest data, by May 16, 246 suspected cases had been recorded and 80 suspected deaths had been recorded in at least three sanitary zones of Ituri province in the DRC, while two additional cases with a history of travel from Congo were detected in Uganda.
Health authorities estimate that there are still significant uncertainties around the true extent of transmission and do not rule out the possibility that the epidemic may be larger.
Lassa haemorrhagic fever
In Africa, health authorities are closely monitoring the Marburg virus, the "brother" of the Ebola virus. It is one of the deadliest known viruses, with mortality in some outbreaks being as high as 90%.
Marburg causes haemorrhagic fever, severe bleeding, multi-organ failure and shock. The absence of an approved treatment or widely available vaccine keeps the virus on the top global surveillance lists. Experts are particularly concerned about long hospital chains of transmission, as the virus can spread through body fluids and contaminated surfaces.
At the same time, in West Africa, experts are closely monitoring Lassa fever, a virus that remains relatively unknown outside Africa but is considered one of the most serious "silent" bleeding threats. The virus is mainly transmitted through rodents, however it can also be passed from person to person, particularly in a hospital setting.
Symptoms include fever, bleeding, respiratory complications, and multi-organ dysfunction in severe cases. Although mortality is lower than Ebola or Marburg, the WHO still considers it a "priority virus", due to the frequency of outbreaks and the possibility of hospital chains of transmission.
The Mpox virus or monkeypox
The mpox virus is another factor of international concern. The new strain of the virus, clade Ib, is at the center of international surveillance, is considered more contagious than previous strains and has led to increased vigilance in Europe, the United States and Asia.
Experts are monitoring locally transmitted cases outside Africa, as several countries are now recording cases without a clear travel history. After all, the geographical spread of the virus seems to be the main reason for its constant surveillance and monitoring, and despite the fact that mpox rarely shows the mortality of other viruses, it is considered a significant threat to public health.
Mosquito-borne viruses are becoming one of the biggest challenges for health systems worldwide
The Hanta virus and the Andean strain
The Andean Hantavirus, the only known strain of the Hanta virus with a documented, albeit limited, possibility of transmission between humans, is of concern. The virus causes severe pulmonary syndrome with high mortality and is mainly found in Chile and Argentina.
International authorities continue to monitor the virus due to its particular behaviour in relation to other strains of the Hanta virus, while inevitably this virus is in the light of day due to the recent outbreak of cases on a cruise ship in the South Atlantic. Each new case, as the competent European Center emphasizes, is carefully investigated, with the aim of avoiding any possibility of the virus adapting to humans.
Dengue fever
Dengue fever is now considered, by many experts, an evolving "silent pandemic".
The number of cases has skyrocketed in Latin America, the Caribbean and Asia, while for the first time there is serious concern about the gradual establishment of mosquitoes/vectors in European regions as well.
Climate change seems to play an important role in the outbreak observed in various regions of the planet, which scientists consider to be the most likely cause of the spread of various infectious diseases.
Areas that until a few years ago were considered safe now have conditions suitable for the survival of Aedes mosquitoes (they are also found in Cyprus), which means that diseases such as Dengue, chikungunya and possibly in the future other viruses
They could have more frequent local transmissions even in Mediterranean countries.
Dengue causes high fever, rashes, unbearable joint pain and in severe cases bleeding complications that can be fatal.
In several South American countries, hospitals are already operating under pressure due to the increase in cases, while international organizations are closely monitoring the course of epidemics.
Experts from the European Center for Infection Control warn of the possibility that outbreaks will become more frequent in the coming years, especially in urban areas with high population density.
Chikungunya virus
In the same context of concern, with Dengue, is chikungunya, a virus that until a few years ago was considered mainly a tropical threat, but is now firmly under the microscope of European public health authorities.
The virus is transmitted through the mosquitoes Aedes aegypti and Aedes albopictus (also found in Cyprus) and causes major epidemics in areas of Africa, Asia and Latin America.
Chikungunya is not a cause for concern because of its mortality but because it causes severe and often chronic joint pain that can last for months or even years after infection.
In many patients, everyday life is significantly affected even after the acute infection has subsided. Experts do not currently refer to a major European epidemic, but warn that the spread of the "tiger mosquito" increases the risk of local transmissions in areas of southern Europe, the Mediterranean, in the coming years.
The Oropouche virus
Another virus that is now under the microscope of the international scientific community is the Oropouche virus.
Although it still remains relatively unknown to the general public, experts consider it one of the most emerging viruses transmitted through arthropods, i.e. mosquitoes, ticks, and other blood-eating insects.
The virus is transmitted through tiny midges and mosquitoes and has already spread to Brazil, Peru and other countries in the region.
Scientists are closely monitoring its evolution, mainly due to the possibility of geographical expansion into new areas, as climatic conditions change and international population movements increase.
Although it is not currently considered a global threat similar to other viruses, it is under increased international surveillance.
