A new virus has come into our lives: shamonda. The French authorities have reported the first case detected in humans of infection by this bunyavirus, which until now had only been transmitted between animals through midges (Culicoides).
This is a man who died at the beginning of October in Lyon with a serious illness. The virological, clinical, radiological and epidemiological data indicate a possible causal relationship between SHAV-EU1 infection and the patient's clinical condition, although they do not yet allow a definitive relationship to be established. Experts are studying "whether the virus caused or contributed to his death and how he acquired the infection." Will the shamonda stay among us? Can it become a zoonosis? The experts consulted by this newspaper ask for caution and assure that the risk to the population is "very low."
"This is an animal virus. Until now, it had been considered that it only affected animals. It is not a zoonotic virus. This case detected in France has occurred in a patient with a serious illness that had caused great immunosuppression. In an immunosuppressed person, any pathogen can enter. For the human species, at this time it would be cautious, because until now no case had been described in humans. And this case has appeared in a person with very particular circumstances," explains the epidemiologist and health expert. Animal, Juan José Badiola.
The also emeritus professor at the University of Zaragoza remembers that "sometimes, having or detecting the virus does not mean that it is the cause of the illness" suffered. For this reason, at this moment he considers that the risk of transmission to humans is "very low, very low," he tells 20minutos. "Nothing, I don't dare say it," he adds.
The director of the Animal Health Research Center (CISA), belonging to the CSIC, Noemí Sevilla, agrees with him, and also asks for extreme caution and to interpret the information "with tweezers." "In principle no diagnosis can be given. This is an immunosuppressed person who has tested positive, but serology has not been confirmed either. It could be a specific issue. He probably had more comorbidities that led to his death. It is not clear that the cause is the virus. You have to take it with tweezers to raise an alarm. Many times you become infected with viruses that do not affect you at all. We are exposed all day to pathogens that our immune system eliminates. I would not raise any alarm. Today We have very little data. We must take into account that it occurred in a person with very peculiar characteristics," says the specialist.
Badiola calls for monitoring the possible presence of the virus and, to this end, suggests carrying out detection tests or serologies on the staff of the farms where the virus has been detected. "It wouldn't be bad to do a test, especially for people with a more compromised immune status," he says. As reported by the Ministry of Agriculture, Fisheries and Food, the Central Veterinary Laboratory (LCV) of Algete, the National Reference Laboratory, has confirmed the detection of the Shamonda virus type 1 in cattle farms in the provinces of Córdoba, Toledo, Ávila, Madrid and, recently, in Girona, where three dairy cattle farms were identified on October 20. Likewise, the presence of Shamonda type 2 has been confirmed in the province of Cantabria.
I wouldn't raise any alarms. Today we have very little data. It must be taken into account that it occurred in a person with very peculiar characteristics.
The expert in Tropical Diseases and International Health and head of Emergencies at HM Hospitals, Justo Menéndez, has spoken along the same lines, maintaining that "except in cattle, the risk of it becoming generalized is very low. In cattle (cows, calves), and also in goats, it is a virus that causes disease. But it does not pose a risk of this becoming a public health problem. The risk is extraordinarily low." In addition, he adds, "it remains to be proven" that the cause of the muervale is the Shamonda virus. "It could have been one more element within a set of causes. It is not a particularly dangerous virus, like others we have known," he explains.
The Minister of Health, Mónica García, also recalled this Friday that the person who died in France "was immunosuppressed" and that the virus affects "cattle." In addition, he assured that the Ministry of Health will put "all the tools and public servers" at the service of the shamonda virus to follow and trace each of the cases, already detected in cattle in Spain.
The World Health Organization (WHO) has not yet carried out a formal assessment of the risk posed by the first case of shamonda virus in humans, although for now it considers it unlikely to spread. "This is a human case and, for the moment, it is unlikely to lead to a broader spread," spokesman Christian Lindmeier said at a press conference this Friday. He added that the transmission of the virus that, like this one, is transmitted by the bite of Culicoides or midges (small dipterans that also transmit bluetongue) "usually decreases during the coldest months of the year."
Species barrier jumping
After highlighting that at this time there is very little information available until the competent health authorities can compile it to better understand the case, Badiola points out that when a virus that affects animals jumps to humans "it usually happens that either the pathogen mutates, or the host (the infected person) of the virus is very receptive to all types of pathogens. Any lowering of defenses is a dangerous situation." The epidemiologist considers this second explanation more likely for the case of the patient from France, who "had a very compromised immune system" and "lived in an area where he had infected cattle", while asking to wait for the results of the investigations of the European Center for Disease Prevention and Control (ECDC, for its acronym in English). The ECDC highlighted in a statement that the severity of the deceased patient's illness made him more susceptible to infections and that it is now investigating "whether the virus caused or contributed to his death and how he acquired the infection."
Badiola points out that the species barrier jump can occur for one or more reasons and that biology "is not an exact science", so a virus can manifest itself differently in different species and even between several individuals of the same species. This is influenced by the conditions of the pathogen, the host and the environment. It is worth remembering how SARS-CoV-2 (which causes covid-19 and which is a zoonosis) occurred in most people as a mild illness but caused death in many millions of other people around the world. Badiola rules out that we are facing the beginning of a Shamonda virus pandemic: "It is an isolated case in very particular conditions."
Very low mortality, without vaccine or treatment
In livestock farming, shamonda virus is considered an emerging disease not subject to mandatory notification, which affects cattle after. They can also infect other species such as goats and sheep, although without apparent symptoms, and horses, among which some cases with neurological damage have been described. The patient notified by the French health authorities had severe immunosuppression and died showing a neurological clinical picture.
Experts explain that mortality among animals infected by Shamonda virus is "very low" and that they normally overcome the disease, for which there is no vaccine or treatment, in a period of 7 to 10 days. As explained by Health, "in cattle, acute infections can occur mainly with fever, a decrease in milk production, between 10 and 20% for 7-10 days, and diarrhea. Morbidity can be very high, affecting up to 100% of the farm, although the majority of adult animals seem to recover. To date, no mortality directly attributable to the virus has been observed. In affected farms in Switzerland, an approximate duration of 14-21 days of the clinical episode".
Contagion occurs through the bite of an infected vector in an animal, but vertical transmission has also been described, from pregnant females to their fetuses, since the virus can cross the placenta and infect the unborn calf, causing abortions or serious fetal malformations. In the case of abortions, Health reminds us of the need to perform brucellosis detection tests.
Shamonda virus was first detected in Nigeria in the mid-1960s and, until 2026, had been reported sporadically in different regions of western, eastern and southern Africa, as well as in Japan. This summer it was detected for the first time in Central Europe, identifying a variant called Shamonda-Europe. In Europe, cases have so far been detected in Austria, Germany, Belgium, Slovenia, Spain, France, Ireland, Italy, Liechtenstein, the Netherlands, Portugal, the United Kingdom (Jersey) and Switzerland.
