The Emergence of Wetland Virus: A New Threat in Tick-Borne Diseases

Wetland Virus: A New Tick-Borne Threat Explained

Ticks are well-known vectors responsible for transmitting more than 25 different human and animal diseases globally, including Lyme disease. However, several new tick-borne pathogens are emerging, some of which are unfamiliar to the medical community and public alike. One such pathogen is wetland virus (WELV), a newly discovered virus that adds another layer of complexity to the management and prevention of tick-borne diseases.

First identified in 2019, wetland virus was discovered in Inner Mongolia, China, where a patient presented to the hospital with fever, headache, vomiting, and symptoms that rapidly progressed to multiple organ dysfunction. Researchers identified the virus as a member of the orthonairovirus genus, the same family as the deadly Crimean-Congo hemorrhagic fever virus (CCHF), which has a mortality rate of 30%. Although WELV is not yet as widespread as some of its viral relatives, its discovery underscores the importance of vigilant monitoring and research in tick-borne diseases.

Understanding Wetland Virus
Wetland virus represents a significant threat as it shares similarities with other orthonairoviruses, particularly in its ability to cause serious infections. The virus was discovered through genetic sequencing, a technique that has revolutionized our ability to detect new pathogens. In the initial case, the patient had been bitten by a tick during a visit to a wetland park. After the patient’s symptoms worsened, antibiotics proved ineffective, indicating that the cause was viral rather than bacterial.

The genetic material from the virus confirmed that it was previously unknown. Researchers linked it to the orthonairovirus family, making it related to viruses that are known to be transmitted through tick bites and which can cause severe diseases in humans.

Epidemiology and Transmission
After the discovery of WELV, researchers conducted extensive studies across northeastern China. These efforts led to the identification of 17 additional cases, indicating that the virus was more established in the region than previously thought. Ticks are considered the primary vector for transmission, and various species, including Haemaphysalis concinna, were found to harbor the virus.

Researchers also screened livestock and wild animals in the region, discovering that sheep, pigs, horses, and rodentscarried the virus, suggesting that these animals could act as reservoirs, potentially allowing the virus to circulate and persist in local ecosystems. While the virus has only been documented in northeastern China, the widespread distribution of the implicated tick species suggests that WELV could have a broader geographic range, possibly extending across Europe and Asia.

Interestingly, 12 out of 640 forest rangers tested for antibodies against the virus, indicating past exposure. This finding implies that wetland virus could be circulating more widely than previously thought, even in asymptomatic individuals. Such cases highlight the importance of continued surveillance and research in at-risk regions.

Symptoms and Clinical Presentation
Patients infected with WELV present with a range of non-specific symptoms, making it difficult to diagnose initially. Common symptoms include:

• Fever
• Headache
• Vomiting
• Dizziness
• back pain
• Nausea and diarrhea

These symptoms overlap with other tick-borne illnesses, complicating the diagnostic process. Laboratory tests in WELV patients have shown signs of tissue damage and blood clotting abnormalities, while one patient exhibited severe neurological complications, entering a coma due to a high concentration of white blood cells in the cerebrospinal fluid.

Despite these severe symptoms, most patients recovered with appropriate treatment and were discharged from the hospital within 4 to 15 days. However, laboratory studies in mice have shown that the virus can cause deadly infections, affecting multiple organs, including the brain. These findings suggest that WELV has the potential to cause more serious infections, especially in vulnerable populations.

Challenges in Detecting Tick-Borne Diseases
The discovery of new tick-borne diseases, such as wetland virus, raises concerns about the rising incidence of these infections and their detection. Several factors contribute to the challenges in identifying and diagnosing tick-borne diseases:

1. Non-Specific Symptoms
Tick-borne diseases often present with general symptoms like fever, headache, and fatigue, which can easily be mistaken for more common viral illnesses. These non-specific symptoms make early detection difficult, especially for healthcare professionals not well-versed in these diseases.

2. Asymptomatic Tick Bites
Many people do not recall being bitten by a tick, as these small parasites can attach to areas of the body that are hard to see, such as the back of the legs. Additionally, tick bites often go unnoticed because they do not cause immediate discomfort, unlike mosquito bites. This makes it harder for patients to link their symptoms to a tick bite, leading to delays in seeking treatment.

3. Delayed Onset of Symptoms
In some cases, symptoms of tick-borne diseases can take weeks to appear after a bite, further complicating diagnosis. For example, Lyme disease symptoms may not present until 3 to 10 weeks after a bite. This delayed onset can lead to missed diagnoses or incorrect initial treatments.

4. Lack of Medical Awareness
In many regions, medical awareness of emerging or rare tick-borne diseases remains limited. Furthermore, the diagnostic tools required to detect these diseases are often unavailable in rural or under-resourced areas. This lack of awareness and resources hinders the timely diagnosis and treatment of patients.

Climate Change and the Spread of Tick-Borne Diseases
A concerning aspect of the rise in tick-borne diseases is the role of climate change in altering tick distribution and activity. As global temperatures rise, ticks are able to thrive in regions that were previously inhospitable to them. This has led to the spread of tick-borne encephalitis virus to countries like the Netherlands and the UK, where the climate was once believed to be unsuitable for the virus.

Lyme disease remains the most common tick-borne illness in temperate regions of the Northern Hemisphere, but other diseases, such as human anaplasmosis and Crimean-Congo hemorrhagic fever, are becoming more prevalent in places like the United States and southern Europe, respectively.

These shifting patterns of tick activity mean that previously unaffected regions may soon face new health challenges related to tick-borne diseases. Medical professionals need to remain aware of these changes and adapt their diagnostic and treatment approaches accordingly.

Prevention and Protection
Given the increasing prevalence of tick-borne diseases, it is essential to take preventive measures when spending time in areas where ticks are common, such as grassy or wooded regions. Some key steps for preventing tick bites include:

• Wearing long-sleeved clothing and long trousers when outdoors in tick-prone areas.
• Applying insect repellent to exposed skin and clothing.
• Conducting thorough tick checks on yourself and your pets after spending time outdoors, especially in wooded or grassy areas.

If bitten, it is crucial to remove the tick as soon as possible. Use fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible, pulling upward with steady pressure. Avoid twisting or jerking the tick, as this can cause parts of it to remain embedded in the skin.

If you develop flu-like symptoms, fever, or a rash after being bitten by a tick, seek medical attention and inform your healthcare provider of the tick bite, as early intervention can significantly improve outcomes in tick-borne diseases.

The Future of Tick-Borne Disease Surveillance
The discovery of wetland virus highlights the need for improved surveillance and research in tick-borne diseases. By employing advanced genetic sequencing techniques, researchers can continue to identify new pathogens and develop a deeper understanding of the epidemiology of these diseases.

In addition to tracking emerging pathogens, it is crucial to monitor changes in tick populations and the diseases they carry, particularly in regions where climate change is expanding tick habitats. This kind of surveillance will help public health officials and medical professionals stay ahead of potential outbreaks.

Conclusion
The discovery of wetland virus serves as a reminder that tick-borne diseases are a growing public health concern. With new pathogens emerging and tick populations spreading into previously unaffected regions, it is more important than ever for healthcare professionals to remain informed about these diseases. By improving diagnostic tools, increasing awareness, and promoting preventive measures, we can better protect ourselves from the evolving threat of tick-borne diseases.