内容摘要：Beijing has called it a "politically motivated and discriminatory action", and its foreign ministry has lodged a formal protest.

Beijing has called it a "politically motivated and discriminatory action", and its foreign ministry has lodged a formal protest.

A marine heatwave is defined as sea temperatures that exceed the seasonal threshold for more than five consecutive days. In the UK the marine heatwave threshold for May is 11.3C.On 19 May the average sea surface temperature reached 12.69C.

"It started in the North Sea and the Celtic Sea. Now the North Sea has cooled down a bit but the west of Ireland is extremely hot," says Dr Berthou.One of the warmest springs on record is driving the surge, as high temperatures and weak winds warm the top layer of the ocean.Marine heatwaves in the UK are thought to be a relatively new phenomenon but they are expected to increase in frequency and intensity.

It is still a bit of a mystery how exactly they will affect marine life, but the signs so far are not good."The interesting thing is that this started in winter and spring, when most people assume marine heatwaves are only in summer," says Dr Jacobs.

People swimming off the west coast of the UK and Ireland may notice the warmer temperatures, although the waters are still cooler than at their peak in late summer.

The worst impacts on species are likely to have been avoided for now because the temperatures have not gone above the upper limit that marine life can tolerate, explains Dr Jacobs.The current all-action approach is a stark contrast to the laissez-faire situation of the past two years, during which there were no pest control measures in Sarajevo at all. Officials blame a botched tender process for extermination and sanitation work, which has allowed the city to go to the rats – and, for that matter, the dogs, as packs of strays are also a common sight around the capital.

Sarajevo Canton Health Minister Enis Hasanovic described the situation as "not a health crisis, but a communal crisis", due to local authorities failing to fulfil essential municipal hygiene requirements.But a former director of the Sarajevo's University Clinical Centre, Sebija Izetbegović, believes the health situation could deteriorate further. Now a member of Sarajevo Canton Assembly, she points out that "well-fed rats" are currently so numerous in the city that "we can also expect hantavirus".

In one respect at least, Sarajevo has been lucky. Left untreated, leptospirosis can be deadly, with a mortality rate of more than 50% for people who suffer from severe bleeding of the lungs.But so far none of the cases reported in the current epidemic have been serious.