INDIANAPOLIS (AP) — Humana Inc.'s third-quarter net income jumped 13 percent after another strong quarter of Medicare Advantage enrollment growth, and the health insurer also raised its 2011 earnings forecast, following a lead set the past couple weeks by other big insurers.

The Louisville, Ky., company said individual Medicare Advantage membership climbed 10 percent to 1.6 million people compared with last year's quarter, mainly because of a successful enrollment season last fall. The insurer's Medicare prescription drug coverage enrollment also jumped 47 percent to 2.5 million people, helped by a low-cost drug plan it offers with retail giant Wal-Mart Stores Inc.

Humana is the second-largest provider of Medicare Advantage plans, which are privately run versions of the government's Medicare program. Subsidized by the government, the plans offer basic Medicare coverage topped with extras like vision or dental coverage or premiums lower than standard Medicare rates. Medicare accounts for 64 percent of Humana's revenue.