Novel and emerging pathogens detected in ticks from wolves in the Iberian Peninsula, Western Europe
This study identifies five tick species and detects novel and emerging pathogens, including the first reported circulation of *Uukuvirus tachengense* and *Rickettsia kotlanii* in the Iberian Peninsula, by analyzing ticks collected from Iberian wolves, thereby highlighting the wolf's role as a sentinel for ecosystem health.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of a preprint that has not been peer-reviewed. It is not medical advice. Do not make health decisions based on this content. Read full disclaimer
In the wild, the smallest creatures often carry the heaviest burdens. Ticks, those eight-legged parasites that attach to animals to feed on blood, are more than just a nuisance; they are nature's most efficient delivery system for microscopic germs. While mosquitoes are famous for spreading diseases like malaria and dengue, ticks are the primary vectors for a vast array of bacteria, viruses, and parasites that can sicken both animals and people. These tiny hitchhikers move through forests and fields, picking up pathogens from one host and depositing them on another, creating a complex web of infection that links the health of wildlife, livestock, and humans. Understanding what these ticks are carrying is crucial because new diseases are constantly emerging, and the animals that roam the wild often act as the first warning signs of a threat that could eventually reach people.
To understand what is happening in the forests of northern Spain, researchers turned their attention to the Iberian wolf. These apex predators are not just top hunters; they are also excellent disease sentinels. Because wolves travel vast distances across different landscapes and interact with many other species, the ticks they carry offer a broad snapshot of the microbial world in that region. For seven years, from 2017 to 2023, a team of scientists collected ticks from 72 wolves in the Cantabria region. They did not hunt the wolves for this study; instead, they gathered ticks from animals that had died naturally or were legally culled to manage livestock conflicts. The team carefully removed 392 ticks from the wolves' fur and skin, sorting them by species and life stage. They then pooled the ticks together and used molecular tools to scan them for any trace of viral, bacterial, or protozoan life, looking for both known threats and entirely new discoveries.
The survey revealed a diverse community of ticks. The most common was Ixodes ricinus, making up nearly two-thirds of the collection, followed by Dermacentor reticulatus. The researchers also found Haemaphysalis concinna, Ixodes hexagonus, and, for the first time ever on a wolf in this region, Rhipicephalus bursa. Once the ticks were sorted, the scientists analyzed them for microorganisms. They found a wide variety of bacteria, including several known to cause disease in humans and animals, such as Anaplasma phagocytophilum, which causes fever in people and livestock, and Ehrlichia canis, a major pathogen for dogs. They also detected Rickettsia raoultii, a bacterium that causes a specific type of skin and lymph node infection, and Francisella, a group of bacteria that includes the agent of tularemia. These findings confirmed that the wolves were moving through an environment teeming with established pathogens.
However, the most significant part of the study was the discovery of viruses. The researchers identified several viruses that had never been seen before in this part of Europe. They found a virus called Uukuvirus tachengense, a known human pathogen that causes fever and other symptoms, circulating in the Dermacentor reticulatus ticks. This was the first time this specific virus had been confirmed in Spain. Alongside it, they found Mivirus boleense and Ixovirus norvergiae, both of which have the potential to be dangerous but had not previously been recorded in the Iberian Peninsula. Perhaps most exciting were the three completely new viral species the team proposed naming. They found a new type of Hudivirus, which they called Hudivirus luzmelaense, a new Ixovirus named Ixovirus borragani, and a new Uukuvirus tentatively named Uukuvirus lebanense. These names honor local places and a veterinarian who contributed to wildlife health, grounding the scientific discovery in the community where it happened.
The study also uncovered protozoa, which are single-celled parasites. They found Babesia caballi, a parasite that typically affects horses, in the ticks, marking the first time it has been reported in ticks taken from wolves. They also detected Hepatozoon canis, a parasite that infects dogs, and Hepatozoon martis, which has been found in badgers and mink. The presence of these organisms in the ticks suggests that wolves are part of a larger cycle where these parasites move between different species of animals. While the researchers could not say for certain if the wolves themselves were sick from these infections, the mere presence of these germs in the ticks indicates that the ecosystem is a reservoir for them.
This work highlights the value of watching the wolves. By examining the ticks on these wide-ranging predators, the scientists were able to map out a hidden landscape of disease risk that would have been difficult to see otherwise. They found that the Iberian wolf acts as a mobile bridge, connecting different environments and carrying a mix of known and novel pathogens. The discovery of new viruses and the confirmation of human pathogens like Uukuvirus tachengense in this region means that doctors and veterinarians now have a better idea of what to look for when patients or animals present with unexplained fevers. It reinforces the idea that the health of the wolf, the health of the livestock, and the health of the people living in these landscapes are all deeply intertwined. The study does not claim that these viruses are currently causing an outbreak, but it does suggest that they are present and waiting, making the wolf a vital early warning system for the health of the entire ecosystem.
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