My sister lives in a neighborhood in Cypress, just NW of Houston. One of her Dachshunds became very ill and the vet couldn't figure out what was wrong with her. They ran all kinds of tests but Sadie died. The autopsy revealed she had been infected by the Hantavirus.
Apparently, rodents such as rats, mice and squirrels carry this virus. (It is more common up North.) They contaminate a pet by drinking or eating out of a pet's dish. There are no symptoms at first. Then it affects the internal organs causing something like Hepetitus. Kidney and liver failure. It is contagious to humans!
My sister has a yellow Lab that stays out back. Sadie would get a drink from that dog's water bowl while she was outside doing her 'business'. So did all the other dogs and cats! Everyone at my sister's house is on antibiotics now, human and critter.