A newly detected virus in Spain has been linked to respiratory illness and potential neurological complications in children, raising concerns about its evolving threat and the need for urgent surveillance. Scientists in Spain recently identified Enterovirus C105 (EV-C105), a rare strain previously associated with respiratory and possibly neurological diseases. This discovery marks the first recorded detection of EV-C105 in Spain, suggesting that it is an emerging strain in the country.
Background on Enteroviruses
Enteroviruses are known to cause a wide range of illnesses, from mild colds to severe neurological conditions. While most infections result in temporary respiratory symptoms, some strains can lead to dangerous complications, particularly in children. Poliovirus, once a global threat, caused paralysis before vaccination campaigns successfully controlled its spread.
Non-polio enteroviruses have occasionally been linked to severe outbreaks. For example, Enterovirus D68 has been associated with acute flaccid paralysis, a rare but serious condition. Although Enterovirus C types are less well-known, their unpredictable nature and genetic diversity have drawn increasing scientific attention. Since its discovery in 2010, Enterovirus C105 has surfaced sporadically worldwide, often connected to respiratory illnesses, but its exact role in causing severe neurological disease remains uncertain.
Study and Surveillance Efforts
The detection of Enterovirus C105 was part of Spain’s national non-polio enterovirus surveillance program, which collects hospital samples across the country. From 2019 to 2024, approximately 2,443 enterovirus-positive samples were analyzed through genetic testing. These samples were taken from patients experiencing various symptoms, including respiratory infections, meningitis, and other neurological conditions.
Researchers used advanced genetic techniques, including real-time polymerase chain reaction (RT-PCR) panels and metagenomic sequencing, to identify and study the virus. Special attention was given to the viral envelope protein VP1 region, a key component in the virus’s ability to infect cells and evade immune responses. Genetic comparison with existing global databases showed that the newly detected strains in Spain had not undergone significant recombination events, indicating independent evolution.
Major Findings
The study revealed that Enterovirus C105 had recently emerged in Spain and was linked to both respiratory and potential neurological illnesses in children. Genetic analysis classified four of the five detected virus strains into a newly identified subgroup, clade C1, which carried mutations in key regions that could impact transmission and immune evasion.
Among the five identified cases, three children presented with respiratory symptoms such as coughing and fever. Two cases involved severe neurological conditions—one child was diagnosed with meningitis, while another developed acute flaccid paralysis, a rare disorder that can cause lasting muscle weakness. Both neurological cases required intensive medical care.
The genetic analysis suggested a connection between the C1 strains found in Spain and those detected in Italy in 2023, indicating a potential link rather than confirmed international transmission. Notably, the virus was only found in respiratory samples, even in patients with neurological symptoms, making diagnosis challenging. This pattern has been observed with other neurotropic enteroviruses like EV-D68 and poliovirus, where traditional cerebrospinal fluid tests may fail to detect the virus.
Implications and Future Concerns
The emergence of the C1 clade suggests a shift in viral dominance, with this new strain potentially replacing older variants like C2. This trend has been observed in other enteroviruses associated with outbreaks, highlighting the need for continuous monitoring. While the study provided valuable insights, the limited number of detected cases makes it difficult to determine the true prevalence of EV-C105 in the population. The absence of cerebrospinal fluid samples also means a direct link between the virus and neurological disease cannot be confirmed.
Experts emphasize the need for enhanced surveillance and improved diagnostic techniques to monitor Enterovirus C105 and prevent potential outbreaks. Current diagnostic tests relying on 5′ UTR targets may not effectively detect this strain due to its genetic differences, leading to possible underreporting.
Conclusion
The identification of Enterovirus C105 in Spain marks a significant development in understanding emerging viral threats. Although cases remain rare, the virus’s association with both respiratory and possible neurological disease underscores the importance of heightened clinical awareness. The emergence of a genetically distinct strain highlights its potential public health risk. Researchers stress the need for continued investigation into the virus’s behavior, its impact on human health, and measures to prevent future outbreaks.
