You are probably mistaking ticks with viruses. Ticks are not viruses. Ticks have to travel from places to places and then spend a long time in one place to multiply and establish a colony. Ticks themselves do not fly, they need to be carried by the host animal. It takes time for them to travel long distances especially when the host is a farm animal that can't roam freely long distances. And even once they travel somewhere, it would probably take couple of seasons to spread locally and establish large numbers.
So I see no logical contradiction by saying "these ticks have been around since 2017" and "entire country is about to be infested".
The old math question asks, "Duckweed is spreading on a lake. It takes 1 year to double the area of duckweed. From start to end, it took 15 years to cover entire lake. Which year the duckweed covers half of the lake?"
Exponential growth has this feature that for a long time it seems fine and then suddenly it is over as it overload's the physical capacity to handle it.
And I would say 7 years to get to the current state is extremely fast rate and definitely cause for alarm in my opinion.
So I see no logical contradiction by saying "these ticks have been around since 2017" and "entire country is about to be infested".
The old math question asks, "Duckweed is spreading on a lake. It takes 1 year to double the area of duckweed. From start to end, it took 15 years to cover entire lake. Which year the duckweed covers half of the lake?"
Exponential growth has this feature that for a long time it seems fine and then suddenly it is over as it overload's the physical capacity to handle it.
And I would say 7 years to get to the current state is extremely fast rate and definitely cause for alarm in my opinion.