You Do Need power plug adapter while traveling from Solomon Islands to Burundi.

Here is Why You Need An Adapter

The outlet and plug type used in Burundi are C and E and in Solomon Islands are G and I. This is how they look like.

Solomon Islands

In Solomon Islands, outlets of type G and I are in use.

Type G

Type I

Burundi

In Burundi, outlets of type C and E are in use.

Type C

Type E