It has recently become official: the summer of 2026 will go down in Swiss history books as one of the hottest on record—and it is feared that such heatwaves will become more frequent in the future. This is a concerning outlook, particularly for the elderly, as heat-induced cardiovascular strain poses a serious threat.

Legionella and ECDC warnings: How do infectious diseases spread?

However, heat also affects us indirectly through infectious diseases favored by prolonged warm temperatures. A recent case in Kleinbasel involved 28 people contracting Legionella, causing one death. The source was identified as a rooftop cooling tower that released the bacteria into the air via water droplets.

For microbiologist Hubert Hilbi (University of Zurich), this is no coincidence: Legionella bacteria multiply optimally at temperatures between 25 and 40 degrees Celsius, with case numbers rising annually by around 10 percent over the last twenty years. His conclusion: "The year 2026 is only the beginning of an increase in waterborne diseases." According to NZZ, Switzerland has neglected the Legionella issue for too long.

Basel is not an isolated case, as highlighted by a late-July report from the European Centre for Disease Prevention and Control (ECDC): the primary issue is not individual heatwaves, but consistently higher temperatures over longer periods. According to the ECDC, four areas are mainly affected: foodborne diseases due to accelerated bacterial growth, mosquito-borne diseases such as dengue or West Nile virus, tick-borne diseases like TBE and Lyme disease due to extended tick seasons, and vibriosis in warm, low-salinity coastal waters. Consequently, the agency calls for closer collaboration between human, animal, and environmental health authorities.

Heat stress in agriculture: Why are Japanese beetles, Orthobunyavirus, and livestock farming facing a crisis?

Agricultural crops are under severe stress. For instance, the invasive Japanese beetle, capable of defoliating entire crops, thrives best in temperatures between 21 and 35 degrees Celsius, according to Timo Börker from the Cantonal Crop Protection Service Basel-Stadt. Whether the heat is purely beneficial for the pest remains to be seen, as larvae may face difficulties due to the dry soil. Which effect predominates will only become clear in the upcoming season.

Currently, many cows in Switzerland are falling ill with a disease causing fever, diarrhea, and other symptoms, often resulting in the death of the animal. In early August, the cause was identified as likely being an Orthobunyavirus, related to the Schmallenberg virus detected in Switzerland back in 2012. The pathogen is transmitted by biting midges of the genus Culicoides, tiny insects from which livestock barns can hardly be sealed off. This disease wave hits at a time when the Swiss meat market is already under pressure due to drought conditions.

According to research by BauernZeitung, the core problem is not primarily the virus itself, but the lack of feed: because grass growth has stalled, many farms are already feeding winter reserves and must decide whether to buy expensive feed or slaughter animals early. According to Proviande, around 7,000 more cows were slaughtered in June and July compared to the previous year, reducing the cow population to its lowest level since record-keeping began in 2010.

These record slaughtering numbers are reflected in falling prices that farmers receive for emergency culling, as reported by NZZ. The federal government responded with emergency aid (full direct payments despite drought, interest-free loans, reduced import tariffs), while the Farmers' Association warns that long-term food security is at risk. Peter Bosshard, Managing Director of the Swiss Livestock Traders Association, summarized the situation: if heat, drought, and the viral disease persist until the end of August, the situation will become even more challenging. The Association of Swiss Vegetable Producers (VSGP) demands that increased production costs and heat-induced lower yields be compensated by the market, as the extraordinary situation jeopardizes the economic viability of many vegetable farms.

Economic impact and climateflation: What crop losses and GDP reductions lie ahead?

As reported by Table.Briefings, grain harvests across Europe are expected to decrease by 7.5 percent compared to the previous year. The Austrian Hail Insurance estimates agricultural drought damage at one billion euros, four times higher than in the previous record year of 2018. Agricultural losses form only part of a broader macroeconomic damage: Triodos Bank estimates heat-related growth loss for the entire EU this year at approximately one percent of GDP, equivalent to 180 billion euros, excluding healthcare costs and property damage such as forest fires. Germany is particularly affected, where low water levels in the Rhine are expected to reduce GDP by 0.3 to 0.4 percentage points, leading insurer Allianz Trade to speak of a "structural economic shock".

Drought also impacts food prices with a delay. As SRF reports, retail prices typically react to crop failures with a one-year lag. "What determines prices this year are last year's events," economist Tomas Dvorak of Oxford Economics told SRF, meaning this year's roughly ten percent lower grain harvest will only manifest at checkout counters in 2027. Climate researcher Max Kotz expects a stronger price surge than last year due to higher temperatures, and Dvorak anticipates that this "climateflation" will soon drive inflation more strongly than geopolitical crises. While agricultural adjustments could mitigate the effects, they cannot resolve the underlying issue.

Whether Legionella, bovine disease, Japanese beetles, or "climateflation," these examples demonstrate that heat acts not only directly on the human body but also creates indirect risks through complex biological and economic systems involving water, animals, plants, and markets. Those who fail to adapt plant breeding, crop protection, animal husbandry, and pricing policies to warmer and drier conditions will soon face these challenges repeatedly rather than once a decade.

Keywords: Heatwave summer 2026 · Drought · Legionella · Japanese beetle · Feed crisis · Climateflation · New breeding technologies · Biostimulants