Hemorrhagic Fever with Renal Syndrome (HFRS) Outbreak: Russia & Europe Update 2024-2026

An increase in cases of Hemorrhagic Fever with Renal Syndrome (HFRS) is being observed in the Republic of Udmurtia, Russia, prompting public health monitoring and preventative guidance. Recent data from the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) indicates fluctuating case numbers over the past five years, with 567 cases and one death reported in 2025 alone. This follows 287 cases in 2021, a significant spike to 797 cases and one death in 2022, 594 cases and two deaths in 2023, and 236 cases in 2024.

Understanding Hemorrhagic Fever with Renal Syndrome

HFRS is a viral disease transmitted to humans by rodents. In Europe, the most common form is linked to the Puumala virus (PUUV), carried by the bank vole (Clethrionomys glareolus). The virus is shed in the urine, feces, and saliva of infected rodents, and humans typically contract the illness through inhalation of contaminated dust or direct contact with these excretions. It’s important to note that, to date, there have been no documented cases of human-to-human transmission of PUUV. More information on Hantavirus can be found at Sciensano.

Factors Contributing to the Rise in Cases

Several factors are believed to be contributing to the observed increase in HFRS cases. A milder winter in 2025 allowed for higher rodent survival rates, increasing the potential for viral transmission. This is compounded by a higher prevalence of infected rodents. In 2025, specialists in Udmurtia captured 1,139 rodents, with 173 testing positive for hantavirus – a 5.8-fold increase compared to the previous year. The bank vole is now the primary vector, accounting for approximately 60% of infected animals.

The bank vole, whereas typically inhabiting forests, can venture into gardens, outbuildings, and even homes, increasing the risk of human exposure. Forecasts from the Kazan Institute for Epidemiology and Microbiology suggest that natural foci of HFRS within the Volga Federal District are expected to intensify in 2026. Seasonal increases are traditionally observed during the winter and autumn months, and the particularly snowy winter of 2025-2026 may further contribute to rodent population growth in the spring.

Clinical Presentation of HFRS

The clinical course of HFRS typically progresses through several phases. The initial, or prodromal, phase involves a high fever (often exceeding 39.5°C) lasting 2-4 days, accompanied by flu-like symptoms and pronounced pain – headaches, lower back pain, abdominal discomfort, and joint pain. Accommodation disturbances (difficulty focusing) are present in around 40% of cases, though they can be fleeting.

This is followed by a hypotensive phase, potentially involving lung issues or cardiovascular changes like fluctuating blood pressure and a slowed heart rate. Hemorrhagic symptoms, such as small skin bleeds (petechiae) or minor nosebleeds, are usually mild. Around 57% of patients develop kidney failure during an oliguric phase, which typically lasts 2-6 days and rarely requires dialysis. This phase is then followed by a polyuric phase.

Recovery is generally complete, although some individuals may experience lingering fatigue for weeks. The overall mortality rate is relatively low, around 0.4%.

Geographic Distribution and Risk Factors

The Republic of Udmurtia, located in the Volga Federal District of Russia, borders the Kirov Oblast, Perm Krai, Bashkortostan, and Tatarstan. The region covers 42,061 square kilometers and lies within the eastern part of the East European Plain. You can find more information about the region at Wikipedia. While the current outbreak is focused on Udmurtia, the broader Volga Federal District is considered at increased risk in 2026.

Individuals at higher risk include those who work or engage in recreational activities in forested areas, particularly those involving buildings or structures that may harbor rodents. This includes construction workers, foresters, and those renovating older buildings or cleaning out attics, basements, or sheds.

Preventative Measures and Public Health Response

Preventing HFRS relies on minimizing contact with rodents and their droppings. Key recommendations include avoiding contact with live or dead rodents and refraining from entering abandoned or enclosed buildings in forested areas. The Russian government, through bodies like Rospotrebnadzor (Rospotrebnadzor Udmurtia), is likely conducting ongoing surveillance of rodent populations and monitoring case numbers to inform public health interventions.

The Russian government maintains a central portal for official information, available at gov.ru. Travelers to affected areas should be aware of the risks and take appropriate precautions.

Looking Ahead: Surveillance and Guidance Updates

Continued surveillance of rodent populations and HFRS cases is crucial for understanding the evolving risk and informing public health strategies. The Kazan Institute for Epidemiology and Microbiology’s forecasts will be closely monitored, and public health guidance may be updated as new information becomes available. Individuals experiencing symptoms consistent with HFRS should seek prompt medical attention and inform their healthcare provider of any potential rodent exposure.