The most important recent piece of legislation passed was the one passed several years ago that I linked earlier and you referred to in your previous post; this piece of legislation will, from the time it was passed until 2016, slowly phase the control of all human-relevant antibiotics into prescription-required status by a veterinarian.
Here is a recent JAVMA article on the topic: https://www.avma.org/News/JAVMANews/Pages/150215o.aspx
As far as high priority targets go, ideally we would like to first control all antibiotic use that might impact human health; part of our veterinary oath is to preserve public health, and with an increasing focus in the idea of One Health, the veterinary role in human medicine will likely only increase in importance within our field. That being said, I don’t think the focus is on any one antibiotic or group of antibiotics; ideally what we’d like to do is put the use of these complicated tools into the right hands in the right situations.
As an analogy, consider if you took your vehicle to a mechanic. The job of a mechanic is very similar to the job of a health professional; they prevent damage to your vehicle and repair damage when necessary. They offer advice about how to care for your vehicle and are general experts on the way that vehicle is constructed and operates.
With medicine, the subject is quite a bit more complicated. Also, if the mechanic makes a mistake, the worst that happens is that the operator or vehicle is in danger of damage. If a doctor or veterinarian makes a mistake, the result is either injury to the patient, or in the case of antibiotic use, the failure of therapy and the development of antibiotic resistance. As you probably know from your experience with family members in the medical field, our patients harbor and live in normal homeostasis with a large array of bacteria that, if we disrupt or cause them to mutate around our use of “tools” like antibiotics, can cause disease or become super-pathogens. The fear is that these pathogens will spread up the food chain to humans or contaminate the environment and eventually become endemic in a given area, e.g. Salmonella, which has done this quite effectively in large animal medicine; an example being a Salmonella outbreak at the renowned New Bolton center at U Penn (the following is a PowerPoint presentation, since the news articles don’t really do the topic justice, and all of the references to journal articles are broken now): https://www.aiha.org/aihce07/handouts/po119boyle.pdf
As far as people experiencing discomfort with antibiotics, I have to admit that I’m unfamiliar with the topic. If you have any experience or information/contacts about this, I be very interested to hear about it, since it could directly impact our animals’ wellbeing as well. Unfortunately, we didn’t learn about this in our curriculum (another reason why we need more cross-talk between human and vet med). I’d be more than happy to take any papers or advice from human professionals that you have to offer to our internal medicine experts here in order to create a conversation for better use with respect to animal welfare.
As far as parasites go, the same rules apply. Resistance develops quicly (though not quite AS quickly) in our parasite populations, and we’ve realized over the last decade that we have been largely over-using anthelmintics/antiparasitics to manage clinical disease in our animal populations. I will admit that I’m not active on the parasite side of research, so my advice might not be 100% up to date, but from what we learned in our parasitology training, we had been using parasitic controls to manage clinical symptoms, when in fact that only accounts for 10% of the parasite population. The other 90% of parasites (in large animals, and for some parasites in small animals) reside in the environment. So while our treatment was eliminating the parasite problem in our patients, it was creating a selective pressure for the development of parasite resistance due to excretion in the feces and subsequent accumulation in the environment, where the vast majority of the parasites reside.
Since we have learned this, we have begun to only use medical parasitic control in a limited fashion to MANAGE instead of try to eliminate parasites. This way, the resistant populations are diluted enough by the non-resistant that when we need to use our drugs, the bugs are susceptible enough to treat.
But to more directly answer your question, the parasitic resistance is very much a growing concern in the last ten years of vet med. Fortunately for us, parasites don’t replicate as fast or in as great of numbers as viruses and bacteria, so they evolve resistance a bit more slowly. They also have a much more complicated organism structure, and therefore can’t evolve as rapidly as bacteria or viruses.