The Doctor who noticed the cluster is from Las Vegas area.
Wikpedia notes a number of reasons for brain abcesses. Infections can arise from dental: dental surgery, head trauma, local infections, congenital heart disease, and weakened immune systems.
The article says that from 2015 until 2019, it was steady at about four cases per year. Then it dipped to fewer in the 2020-21 period. Then spiking at around 16 or more in tge 2022.
The article points out that the pandemic kept kids at home and may be tge reason for the reduced cases. Then suggests the reopening of schools may have brought about the spike.
Maybe. But I would expect the number to return to their previous levels in that case. We know that Trump secured the border and governments across America implemented lock down procedures that closed schools. Then, after Biden took office, their was a surge in in covid vaccinations, reopening of schools, and the opening of the border.
So I wonder if perhaps kids who came through our porous border, got covid shots (and perhaps the normal rounds of childhood vaccinations) to go to school, might be a big part of the cases in the spike.