I have seen these posters too. I have also seen postcards from the USA with almost exactly the same scene, could even be the same women. Means I am not sure where the pics were taken. If it was a US picture then they may well have been using Italian stock, if in the UK its late enough for it to be some of the early buckfast. However, also have pics of old timers here, and I think your mention of them being a tougher than we are today hits the nail on the head. Working with their veil back over the face so they can drop it down quickly, yet I could see the stings and in one case a bee was trying to get away with its sting embeded in the keepers nostril attached by a string of its own internal 'bits'. (Technical expression!) Seemed unfazed by it. Wonder how many of them eventually went down with allergy? There were many stories of old beekeepers who used to have to carry 'heart tablets' in a phial round their neck that they had to take if stung. They also simply did not have the range of protective gear we have today.
As for the disease bit, well yes of course transmission from outside is a constant risk, and EFB was found last year, and again this year, in a unit less than two miles away and AFB not much further away in hives belonging to the same keeper. Total vigilance and elimination of risk of cross contamination is the order of the day for my men on site. Find anything, deal with it immediately.
As for going to NZ. Reversed seasons and reliability are a key factor, and the bees are simply bred there to take advantage of that. They are actually European stock, mostly from Germany. Their list of tests is bigger than those done here, and were so severe that for three years they were actually unable to export to the EU because of their own export rules, which rendered it impossible to ship (technicalities regarding testing and timing issues, where the tests on all colonies and the shipping out had to be done inside 24hours, which can be fully explained but will make your eyes glaze over.). I worked with them and NZMAAF, plus the UK authorities, and the issues were resolved. One thing about their certification that might be of interest is that no foulbrood whatsoever must have been found anywhere within 6 miles of EVERY apiary of origin withing the preceding three years, and the shipper has to pay for a survey to be done and for every beekeeper to have been visited and checked. An onerous task, although less so than here as there are far fewer beekeepers and those that are there keep bigger lots. Also means they need to keep better relations, because of even one in the 6 mile circle will not co-operate (try that here!) then the certificate cannot be issued. (And its only AFB btw, as EFB is not found in NZ).