The rats shown are not African crested rats, their hair was too short. Crested rats have very long hair and much more closely resemble a porcupine than they do a rat. In fact most people in New York would not know it as a rat if they saw one.
The African black crested rat is poisonous, not venomous, being bitten by one would not be any more harmful than any other kind of rat. They do not actually produce their own poison, they use the poison from the poison arrow tree, which they rub on their fur. Rats of this species kept in captivity would not have any poison on their fur. Even if they did the only way they would be harmful to a human is if that human licked one or tried to eat it.