#19,386
In early August, we looked at a statement from the Swiss FSVO (Federal Office for Food Safety and Veterinary Affairs) on their Investigation into an Unidentified Bovine Disease which produced fevers, diarrhea, and substantial milk drop in dairy cows.
A few days later Germany's FLI (Friedrich Loeffler Institut) announced the results of their own investigation, which had discovered high levels of a novel orthobunyavirus of the Simbu serogroup present in affected cattle.
Orthobunyaviruses are a large and growing family of `arboviruses' - viruses carried and spread by biting insects and ticks (mosquitoes, ticks & midges) - that mostly infect animals, but are sometimes zoonotic.
The FLI's press release dated August 3rd stated:Viruses of the Simbu serogroup are not generally considered to be zoonotic agents and, based on current knowledge, do not pose a significant risk of infection to humans. However, in the case of newly emerging and insufficiently characterised viruses in this group, their potential zoonotic risk should be investigated as a precautionary measure and closely monitored as the situation develops.
Last Thursday, the journal Eurosurveillance published the first account of a (fatal) human infection with this virus in a highly immunocompromised patient living in a rural region of France.
For now, this appears to be a rare occurrence, but investigations continue into the epidemiology of Shamonda-Europe 1 (SHAV-EU1) virus.
Due to its length and technical detail, I've only posted some excerpts from the Eurosurveillance report. Follow the link to read the Rapid Communication in its entirety.
I'll have a bit more after the break.
Open Access
Volume 31, Issue 42, 22/Oct/2026Fatal encephalitis caused by Shamonda virus Europe 1 (SHAV-EU1) in a patient with a severely weakened immune system, France, 2026
Margot Bonnet1,* , Hélène Labussière-Wallet2,* , Pauline Dumez3,* , Lucie Jauffret4 , Lyderic Aubert5 , Aurélie Avondo-Ray5 , Carole Seurret3 , Perrine Devic3 , Sabrine Souci3 , Syria Laperche6 , Léa Saint Martin7 , Emilie Frobert7,8 , Alexandre Gaymard7,8 , Jennifer Giorgi7 , Quentin Semanas7 , Richard Chalvignac7 , Antoine Oblette7 , Audrey Lapendry7 , Bruno Pozzetto9 , Thomas Perpoint10 , Mikail Kelleci11 , Aurélie Sécula11 , Charlotte Foret-Lucas11 , Clement Javaux10 , Florence Morfin7,8 , Antonin Bal7,8 , Elise Brottet12 , Catarina Krug12 , Frederic Jourdain12 , David Meyronet13 , Florence Ader10,14 , Jean-Luc Guérin11,** , Laurence Josset7,8,** , Grégory Destras7,8,**
Clinical presentation
On 23 September 2026 (day (D)0), a patient in their sixties developed acute cortical blindness and confusion, with normal brain magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) examination. This patient had a history of T-cell prolymphocytic leukaemia diagnosed in November 2025. They underwent first-line treatment with alemtuzumab (Campath) from December 2025 to February 2026, followed by an allogeneic haematopoietic stem cell transplantation (HSCT) on D−28 from a human leukocyte antigen (HLA) matched related donor. The conditioning regimen consisted of thiotepa, fludarabine and busulfan and the graft vs host disease (GVHD) prophylaxis consisted of post-transplant cyclophosphamide and cyclosporine. The patient lived in a rural area in the French Rhône-Alpes region. They had been hospitalised in Lyon continuously since 18 August 2026, corresponding to D−36 (Figure 1).
(SNIP)
Discussion
Here, we report the first human case of SHAV-EU1 infection, an emerging Orthobunyavirus that spread over Europe in summer 2026 affecting predominantly cattle. The patient, who had a severely weakened immune system, died from multi-organ failure including neuro-invasive disease, with primary neurological symptoms appearing on 23 September.
Investigations into the viral course revealed that the virus was present in the patient's blood for several weeks. At this point, we cannot date the time of infection as the earliest sample investigated was already positive for the virus on 2 July. Given that the first detections in cattle were reported in early July and clinical signs were documented in dairy cattle as early as June 2026, the patient was probably infected between mid-June and 1 July 2026. Investigation of the patient’s clinical history revealed that they developed an episode of diarrhoea and anorexia on 19 June, similar to symptoms observed in adult cattle [2] and could correspond to the first symptoms of this infection. Investigations on earlier blood and available respiratory samples are ongoing to determine the first detection of the virus over the clinical course by RT-PCR as well as by genomic investigation.
Route of transmission also remains unknown at this point. Graft transmission has been ruled out due to the negative PCR test of the graft and the previous positive PCR of the blood sample. Three different transmission hypotheses are currently investigated. As observed in animals, the most likely is the vector-borne transmission, presumably Culicoides spp. biting midges near the patient's home located in a rural area where animal transmission of SHAV-EU1 was officially documented in early July 2026, although transmission was likely already occurring in June 2026. The potential involvement of alternative arthropod vectors should also be explored. The two other routes (transfusion and food-borne) are less likely, given the sequence of events, and are not supported by any evidence at this point although investigations are ongoing to rule them out. Transfusion-related transmission would require an immunocompetent donor with asymptomatic viraemia in June, while viraemia is reported very transient in animals. Transmission by raw milk or raw cheese appears unlikely, as the presence of the virus in milk has not yet been reported and there is currently no evidence of direct contact-mediated transmission between animals.
(SNIP)
ConclusionWe present the first case of human infection by the Shamonda-Europe virus, specifically the clade EU1, which emerged in European animals in June 2026. However, given the patient’s significantly weakened immune system, this finding alone cannot currently be interpreted as a serious risk for the general immunocompetent population.
The primary hypothesis of transmission remains Culicoides biting midges and although direct human-to-human transmission appears unlikely, transmission through blood transfusion or organ transplantation remains a potential concern. Further investigations are warranted to better characterise transmission routes, particularly potential vector-borne transmission. This case calls for an enhanced surveillance of Shamonda Europe virus in both human and animal settings in Europe.
Fifteen years and more than 15,000 blog posts ago, I wrote a piece called The Third Epidemiological Transition, based on the works of the now late (May 22, 1936 - May 15, 2014) anthropologist and researcher George Armelagos of Emory University.
The gist of his theory - which he first published in the mid-1990s - was that since the mid-1970s the world had entered into an age of newly emerging infectious diseases, re-emerging diseases and a rise in antimicrobial resistant pathogens.
While most of these threats will never rise to pandemic proportions, their impact on our lives and our economies can still be significant. Our current battles with measles in North America and dengue fever in Florida, are just two of many examples.
While the Shamonda-Europe virus seems unlikely to pose a significant public health threat, one can never truly predict what an emerging disease will do. Viruses can evolve, environmental conditions can change, and suddenly a minor threat can become more formidable.
Which is why there is value in our tracking these outbreaks, even when they seem mostly of academic interest at the time.
