CHICAGO (Reuters) - Officials in three states tried on Monday to track down pet prairie dogs believed spreading "monkeypox," a smallpox-like illness not seen before in the Western Hemisphere that may have infected 37 people. Only six of the victims were being treated in hospitals, officials said, and they were expected to recover with bed rest. The disease, caused by monkeypox virus, is not believed to spread person-to-person. But in light of the Severe Acute Respiratory Syndrome scare and an approaching summer season when mosquito-borne West Nile virus was likely to again pose a deadly threat, health officials were moving...