What you need to know about Oropouche Virus Disease

The European Centre for Disease Prevention and Control (ECDC) has issued a warning to travellers to Latin America and the Caribbean, where Oropouche Virus (OROV) disease is currently circulating. According to the ECDC, more than 8,000 cases have been reported in these regions since January, and 19 imported cases were reported in Europe for the first time in June and July, including 12 in Spain, five in Italy and two in Germany.

ECDC Threat Assessment Summary Last week it was announced that one of the infected people had traveled to Brazil, and the other 18 had traveled to Cuba. However, this year cases have also been reported in Bolivia, Colombia and Peru. The overall risk of infection for travellers from Europe to OROV-endemic countries is assessed as moderate, but the risk is higher in some northern Brazilian states and municipalities in the Amazon region with high infection rates, and if personal protective measures are not observed.

An editorial published last week Lancet infection OROV has been described as a “mysterious threat” and knowledge about it is limited, despite around 500,000 documented cases since it was first detected in Trinidad and Tobago in 1955.

OROV is transmitted primarily by infected chironomids (Curicoides paraensisHowever, some mosquito species can also spread the virus, causing symptoms very similar to those of other arbovirus infections in the same area. Dengue feverChikungunya, and Zika virus infection.

In most cases, the symptoms are mild, Meningitis and encephalitis As likely as possible to occur Fetal death There have also been reports of birth defects and malformations due to infection during pregnancy, and the first deaths were reported last month in two young Brazilian women with no comorbidities.

Medscape Medical News Professor Jan-Felix Drexler of the Institute of Virology at the Charité University School of Medicine in Berlin, Germany, said: Oropouche fever outbreaks in Latin AmericaWhat clinicians need to know about OROV disease.

What are the main symptoms of OROV disease that clinicians should look out for?

The main symptoms are no different from other arbovirus infections: fever, joint and muscle pain, and rash. The problem is that we don't know how often severe disease occurs, because we don't know whether the previously assumed severe cases, such as deaths and congenital infections in seemingly healthy people, are due to increased testing, changes in the virus, or a changed, more intense circulation (so more infections only lead to rare severe cases). Be vigilant and get your patients tested.

If a recent traveler to an infected area presents with symptoms, what is the differential diagnosis? Are there any clues that would indicate the illness is Oropauche fever rather than something like Zika?

The main message is not to assume a specific infection based on clinical symptoms, but to consider OROV disease in the differential diagnosis if the patient has returned from or lives in an endemic area.

What personal protective measures should clinicians advise travelers to infected areas to take? Are these different from regular mosquito control measures?

Repellents are crucial, as always. But there are differences: the size of the holes in mosquito nets should be smaller than those used against malaria and dengue vectors, which means they need to have a higher mesh. The problem is that higher mesh netting can be tricky in very hot and humid environments, as it also limits breathability. Travelers should discuss the best trade-off with local suppliers.

The risk of being bitten by midges seems to be highest at dawn and dusk, when it is windless and humid. Therefore, on the one hand, it can be recommended to avoid these areas and to be outdoors at these times of the day. On the other hand, specific recommendations cannot be made firm at this time, since vectors by other invertebrates cannot be excluded. Some studies suggest that mosquitoes may also transmit the virus. If this is true, then again, bites should be reduced.

Should pregnant women be advised to avoid travel to affected areas?

Not immediately, but caution is warranted. There are insufficient data to assess the risk of potential congenital infection. More epidemiological data and controlled infection experiments will be needed before evidence-based recommendations can be made.

All the cases reported in Europe so far have been imported from Cuba and Brazil. Is there a risk of contracting the virus there, for example through mosquitoes on an airplane? Airport Malaria?

Not immediately, but it cannot be ruled out. Little is known about the vector's infectivity, and controlled infection experiments need to be done, including the vector's resistance to insecticides commonly used on airplanes.

What is the risk of an animal reservoir emerging in Europe?

We don't know, but there's no need to sound the alarm. Controlled experiments and surveillance will be required.

Is treatment purely supportive or are there specific agents worth trying if there is severe symptoms/neurological involvement?

At present, no specific treatment can be recommended, however, severe dengue demonstrates the importance of supportive care, which can be highly effective in reducing mortality.

of Lancet “Although several laboratory tests have been developed, few robust commercial tests are available,” the paper states. What are the chances that European laboratories will be able to test for Oropouche?

The European testing network has already taken steps, and tests are now available at least in key and reference laboratories. Clinicians who order OROV tests will likely get a definitive answer within a reasonable time frame. Of course, the situation will improve as cases increase and more laboratories with testing capabilities become available.

Do you think there's anything else clinicians should be aware of?

Most importantly, think beyond what you learned in your medical school textbooks: In a climate-changed world, things change quickly.

Professor Drexler has no conflicts of interest to declare.

Dr Sheena Meredith is an established medical writer, editor and consultant in the field of medical communications, with extensive experience writing for medical professionals and the general public. She is qualified in medicine, law and medical ethics.