Thank you. I was wrong with using with, with treat ;)
"Thirdly,from the medical perspective,there are many contagious diseases from pets. For example, a friend of mine died recently because contacted a disease from this dog. I do want to have the same fate!"
or this one: from the hygienic perspective, there are many diseases that can spread through contact with animals. Like various types of leaches. For instance, ...
I think using first,... second,... and ... in-conclusion is not wrong and
firstly, secondly , finally... is also true.
I donot want to have the same fate!"
;)