On the trail of the Jordan virus

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Extraction 1 (Photo: Denise Altenbach, Agroscope)
Extraction 1 (Photo: Denise Altenbach, Agroscope)
Changins/Wädenswil, 24.05.2022 - Jordan virus is a new threat to Swiss agriculture - especially to tomatoes and peppers. Agroscope is playing a key role in combating this quarantine organism in Switzerland. A newly created research group diagnoses submitted plant samples in the quarantine laboratory using PCR testing. If positive, tough measures are needed to prevent spread and limit damage: recently, a shipment of 6000 seedlings had to be completely destroyed at Zurich airport.

Films are made of this stuff: A shipment of around 6000 tomato seedlings arrives in Switzerland by plane. Inspectors from the Federal Plant Protection Service (EPSD) take individual plants and send them to Agroscope in Changins (VD). In a specially secured quarantine laboratory, researchers examine the plant samples for the Jordan virus. On the following day, the result with the detected jordan virus is available. Agroscope immediately reports the result to the EPSD. The EPSD decides that the shipment must be completely destroyed at the airport.

Global trade on the rise

The case described above is no longer an isolated incident. With the global trade in seeds and seedlings, new pests are increasing in Switzerland. Last year, Jordan virus was detected for the first time on imported plants in Switzerland. So far in 2022, Agroscope has tested three imports, two of which were positive. "It’s a battle against time," says Denise Altenbach, head of the Molecular Diagnostics Research Group for Regulated Plant Pathogens. "We have to send the results of the molecular tests to EPSD at the airport no later than 48 hours after receiving the plant samples. We cannot afford to make mistakes. It must be prevented that infected seedlings end up in production plants and home gardens." The team around Denise Altenbach was newly created at Agroscope in November 2021 specifically for such analyses. It is still being set up and will be expanded further.

Up to 1000 samples planned

The EPSD, and with it the Agroscope Plant Protection Service, work closely with the Cantonal Plant Protection Services (KPSD) to combat the Jordan virus. A trio that works well to prevent the spread of the contagious virus. This goal can only be achieved by detecting the virus early. This year, up to 1000 spot checks are planned, for example, in tomato and bell pepper production plants and in nurseries or garden centers. In addition, there are the missions that cannot be planned, as in the case of imports described above.

Drainage water is also examined

Drainage water from greenhouses is also tested for Jordan virus. This procedure is also used for coronavirus with wastewater from sewage treatment plants. If a random sample is positive, for example at a production facility, fruit harvesting can continue under strict hygiene measures. This is because experts consider the risk of spread through fruit to be low and the damage to producers would be disproportionately high. After the end of the season, all plants must be burned and all affected greenhouses, including the irrigation circuit, must be decontaminated.

International exchange is important

"We try to protect agriculture from the virus," says Denise Altenbach, explaining her role in the fight against the virus, which is harmless to humans. "Similar to influenza and Covid-19, it is not always easy to distinguish an infestation with Jordan virus from other viruses based on symptoms alone. Only our molecular tests clarify whether or not it is Jordan virus." Another piece of the puzzle in the fight against jordan virus is the international exchange in which Agroscope participates. This allows Swiss experts to benefit from the experience of other countries that have been struggling with the jordan virus for some time.

Background information

Jordan virus (Tomato Brown Rugose Fruit Virus, ToBRFV) has been detected in Switzerland for the first time in 2021 - in a Thurgau tomato production farm. This plant disease affects tomatoes and peppers; no other host plants in the field or in the environment are currently known. Yield losses of up to 100 percent are possible. Jordan virus is highly contagious. It survives for long periods on plant debris, in soil, and in greenhouses. As a quarantine organism, Jordan virus is subject to notification and control and is monitored by the federal and cantonal plant protection services.