By definition domestic cats are not an invasive species. This is a discussion post. The USDA-United States Department of Agriculture describes as per Executive Order 13112 an “invasive species” as a species that is (1) non-native (or alien) to the ecosystem under consideration and (2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health. I’d argue that were there are negative and positives to the presence of a non-native species you have to weigh up the two and arrive at a balanced result.
Domestic cats are non-native to America. We have to agree that. Although I don’t know how far you can go back before deciding that cats can remove themselves from the label of being non-native. It’s an unnecessarily derogative description.
Nonetheless, taking all factors into account on balance I do not think that it can be argued that domestic cats harm human health. I know cat haters and trolls will say that domestic cats harm human health but they are demented individuals with an axe to grind.
The truth of the matter is that there is ample evidence that domestic cats improve the health of their owners. There are millions of articles about it on the Internet. They keep countless millions of elderly people company, quite possibly improving the longevity of these people.
There are very few zoonotic diseases which are transmitted by domestic cats to their owners and therefore it is highly unlikely that a domestic cat will transmit a disease to their owner. Cat haters will refer to toxoplasmosis but this disease is acquired in a number of ways other than from domestic cats and in nearly all instances it is benign in the human.
Of course, there are feral cats. But this is due to irresponsible behavior by cat owners. It’s our fault. You can’t blame a cat for that. And in any event the impact that feral cats have had upon the environment are exaggerated. Ornithologists like to exaggerate for obvious reasons.
Of course feral cats do have a negative impact upon the environment (i.e. bird predation) but even that should be set against benefits such as rodent control. When you take everything into account including the positive benefits to people of the domestic cat – which is why they look after them in the countless millions – and set this against environmental damage caused by feral cats I don’t think you come out with a net negative result.
It is arguable therefore that the second part of the definition of invasive species is not fulfilled. Of course you can successfully state that domestic cats are non-native. That’s almost undeniable but to go one step further and rant and rave about domestic cats being an invasive species transmitting diseases to millions of humans as if we were going through a second bubonic plague is a huge misrepresentation.