Crimea-Congo, Zika, Chikungunya, Dengue ... This is the exotic virus that stalks us
They have curious names, which take us back to exotic and distant places; but they are closer than we think. Viruses like chikungunya, zika, dengue or Crimea-Congo have stopped
- Alarm: A woman entered in Seville for possible Crimea-Congo virus infection
- Chikungunya in Spain Symptoms, causes and measures to prevent infection
They have curious names, which take us back to exotic and distant places; but they are closer than we think. Viruses such as chikungunya, zika, dengue or Crimea-Congo have ceased to be those strange pathogens that could not be acquired in Spain. Globalization and climate change are making their way. And, like a drip, the first native cases have begun to be recorded.
Just a few days ago, the alarm in Seville jumped at a suspicion of Crimea-Congo, a type of hemorrhagic fever that is transmitted by the bite of an infected tick. As a precaution, the patient, a 74-year-old woman, was immediately subjected to isolation measures, although, finally, an analysis by the National Center for Microbiology ruled out the disease.
"There were all the criteria that make it necessary to implement the protocol of action", explains José Miguel Cisneros , director of the Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine of the Virgen del Rocío Hospital in Seville, the center where he remained under isolation the patient.
"In the case of a suspicious case, you always have to act," says the specialist, who recalls that, although not serious in all cases, the virus is one of those considered "highly transmissible," which requires special measures to protect all to the health personnel - the most vulnerable - of new infections.
In Spain, the first two clinical cases of Crimea-Congo were diagnosed in 2016 , although it was known that, since 2010, the pathogen was already present in ticks of the genus Hyalomma in rugged areas of Andalusia, Extremadura, Castilla-La Mancha, Castilla and Leon and Madrid.
The first case in humans occurred in a 62-year-old man who, after suffering a tick bite on a field trip in the province of Ávila, began to experience symptoms compatible with the disease. Next, one of the nurses who treated him contracted the virus, which in addition to the arthropod bite, can be transmitted by direct contact with blood and other contaminated fluids.
In 2018, two new cases were registered, although the last one was identified retrospectively by an investigation that a team from the University of Salamanca conducted a few months ago.
"It is a disease of importance in public health in the European region that has become endemic in Turkey and the Balkan region," says Antoni Trilla , head of the Department of Preventive Medicine and Epidemiology at the Hospital Clínic de Barcelona and one of the members of the network of experts who, in our country, ensure that these so-called emerging viruses are kept under control.
There are several factors that explain why pathogens that used to be limited only to certain locations are experiencing a true global expansion. And they are summarized in three keys: climate change, deforestation and global interconnection .
"Globalization, in its broadest sense, facilitates the rapid transfer of people, animals and goods throughout the world," says Trilla. "And viruses are one of the species that has taken advantage of this phenomenon, being able to move from one point to another on the planet in a few hours," he emphasizes.
In addition, says Natalia Rodríguez , researcher of the Emerging Virus Program of the Institute of Global Health in Barcelona, the boundaries between urbanized areas and virgins in nature are increasingly permeable, which facilitates human contact with certain pathogens.
Finally, what has just created this 'perfect storm' for viruses is global warming, which favors the presence in new locations of vectors that these infectious agents need to reach humans.
What happened with the 'tiger mosquito' in Spain is a paradigmatic example of this phenomenon.
Until 2004, Aedes albopictus , the scientific name that the insect receives, was not present in the Iberian Peninsula, so there could be no indigenous cases of some of the diseases it transmits, such as dengue, Chikungunya or Zika.
Today, however, this mosquito has been established in municipalities in all the provinces of Catalonia, Aragon, Valencian Community, Region of Murcia, Balearic Islands, Basque Country, Extremadura, Community of Madrid and much of Andalusia, according to data from the Ministry of Health.
Viruses are one of the species that has taken advantage of globalization, being able to move from one point to another on the planet in a few hours
Therefore, it may be the case that an international traveler becomes the index case of an infection when returning to Spain with an imported virus . Although there are no symptoms, the virus of the disease already circulates through its blood; so, if a local mosquito bites you, you can start a small chain of transmission in which citizens who have not moved from the country are affected.
Something like that was what happened in 2018, when the first indigenous cases of dengue were notified in Spain, a disease that, although in the vast majority of cases is not serious, can cause serious complications in a small percentage of those affected, especially if coinfections occur.
Health confirmed, in early October of that year, that three members of the same family had contracted the disease on a summer trip through Andalusia and Murcia. A few days later, two other new cases were reported, possibly associated with the first; and already in November, the health authorities reported another additional case that did not seem to be related to the previous ones.
A thorough investigation was carried out and, finally, epidemiological and microbiological studies showed that contagion had occurred from two cases of imported disease thanks to the 'collaboration' of local tiger mosquitoes.
It seemed that the same employer was going to repeat himself last June, when the health authorities reported the first indigenous cases of Chikungunya.
A hospital in Reykjavik claimed to have diagnosed the disease to three members of the same Icelandic family who had spent a few days on vacation in Alicante in May.
A subsequent analysis, however, ruled out the disease. But no public health specialist was surprised by the first announcement. Because they have known for a long time that in our country there are the necessary conditions for the arrival of this and other viruses, such as Zika , which between 2015 and 2016 caused a serious epidemic in Latin America.
"In nearby countries, such as France and Italy, autochthonous cases of Chikungunya have already been registered," says Fernando de la Calle , specialist of the Tropical Medicine and Traveler Unit at La Paz-Carlos III Hospital (Madrid) .
Although Spain has become a friendly destination for these pathogens, the specialists consulted do not believe that large outbreaks of these diseases will occur in the immediate future. "I think, at least in the short term, these viruses are not going to be common in our country . We will probably see new cases, but anecdotally," predicts De la Calle.
"Both in our country and in Europe there are high-level surveillance systems and action protocols that would allow, in any case, to control diseases," agrees Cisneros; underlining a fact that also highlights sources of the Center for Coordination of Alerts and Emergencies (CCAES), the node that 'patrols' the presence of emerging diseases in our country.
Our health today is global. And it means being aware not only of what happens to humans, but also to animals and the environment
"The Royal Decree of the National Epidemiological Surveillance Network of 1995 was amended in 2015 to include new diseases of interest, among which are many of these diseases," said the sources cited. And that, they clarify, implies not only the mandatory notification of cases or the implementation of specific response protocols, but also the development of alert systems, such as the entomological surveillance project that, at airports and ports, is attentive to possible Imported vectors of infectious diseases.
"We have great professionals in all the fields involved, but the real endowment of technical and especially human resources is manifestly improvable," regrets, however, Trilla, who recalls that despite the fact that "we must prepare for crises in times of peace and tranquility " , the epidemiological and microbiological surveillance systems are" the poor sister of Cinderella's poor sister in Spain ".
Chikungunya, dengue, zika or Crimea-Congo are some of the emerging pathogens that could more easily be transmitted in our country. But are not the only ones. Other agents, such as the MERS and SARS coronaviruses, the new influenza viruses, or the so-called disease X - the name that the WHO has used to designate that still unknown disease that, at any time, can make the leap to humans - They are also a major threat.
"Our health, today, is global," concludes Trilla. "And it means being aware not only of what happens to humans, but also to animals and the environment. We have only one world and also one health."
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