Due to Charlie's current bout with whipworms and hookworms, I am now looking at all the preventatives and I am so confused. Is there anything that protects against whipworms, hookworms, roundworms, heartworms, fleas and ticks? All of these are problems where I live and I'd like to be able to give him just ONE preventative but, so far as I can tell, there isn't one for everything. I don't like using any of these chemicals at all but what other options are there? What do you guys do?