Strange Bee Behaviour

My garden is full of bees at the moment, loving the lavendar, comfrey, borage and sunflowers. However, I've noticed many bees seemingly 'stuck' come dusk, when I would expect them to be flying off home. They seem especially clingly to the lavendar and sunflowers. I've also seen some crawling seemingly aimlessly up the house walls and others dead on the path.
I thought at first they might just be drunk on all that lovely nectar but my son says it might be due to a blood-sucking parasite he's read about.
A quick Googe revealed this article, which does ring bells in terms of how the bees I'm observing are behaving, but this article says the parasite has only been detected in N America (although it was written 18mnths ago so maybe it's spread/been detected elsewhere since then?)

http://news.discovery.com/animals/zoo-animals/parasite-bees-zombies-010512.htm

Anyone else noticing anything similar? Anyone able to offer further insight? Is there anyway we gardener can do battle against this parasite, if that's what the cause of the ailing bees is?

Thanks

 

I don't think they can kill the varroa mite without harming the bees a little. but I'm sure I've heard that the varroa mite can only kill honey bees because the mite is unable to get inside bumble bees.