PESHAWAR, Pakistan — Gunmen killed two anti-polio workers Sunday in northwest Pakistan, police said, the latest violence directed at efforts to eradicate the disease from the country. The two attackers shot the two Pakistani health workers while they were on a vaccination drive in rural Kandar village, said Swabi District Police Chief Mohammad Saeed. The gunmen arrived on foot and later disappeared, he added. No one claimed responsibility for the Sunday attack. But some Pakistani militant groups…