Yes, you're absolutely right, Pete. Sorry, think I was assuming that they would be kept in a fenced off garden & house. Yep, there are a lot of street animals in various stages of health & aggressiveness. Absolutely the best idea to keep your house pets away from them as much as possible, for their health & their safety. Some street dogs will be perfectly friendly to a "newcomer dog" and others will see him as an interloper on their territory & start a fight. And Pete is perfectly right about the cats (street cats here are very streetwise). Also packs of street dogs have been known to attack cats.
Make sure your garden is adequately fenced off. Teach any staff (gardener/cleaner) you may have in to keep the gate shut. When you walk your dog (if you decide to exercise him that way), use a leash & carry a stick to discourage street dogs (you don't need to use it, the threat is enough). As for the cats, are they house cats? If so, really best to keep it that way.
I don't mean to alarm you, these precautions should be more than adequate to protect your pets. It's just that there are a lot of strays & it's better to be forewarned. Also, if your animals are females, best to get them neutered, so they don't encourage the opposite sex to congregate near your gate when they're on heat. Actually, get males neutered too, so they're not inclined to wander when a female outside is on heat (not just the wandering to worry about, a few dogs have VG [a contagious & dangerous genital tumour] & you don't want your dog to get that from mating

not sure if cats get VG, I'll have to check that out )
Anyway, hope we haven't worried you too much. None of my pet dogs have ever been involved in any sort of fight or problem with street dogs in the 5 years I've been here, but I never allow them to roam, they're always in the garden (walled) or on a lead with me. I do let them off the lead in places with few dogs, but you have to be here to suss those places out yourself. I've never owned a cat, but I think they're best kept inside

"The question is not, can they reason? Nor, can they talk? But, can they suffer?" - Jeremy Bentham, philosopher, 1748-1832
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