Space Australian Medicine
Despite the best efforts of everyone involved, something truly nasty escaped Earth. They call it giardia, a microscopic organism that their Planetary Protection Officer called “pretty dumb” and “not too bad, really, a week of digestive upset and then it’s over.”
Yes, Earth has a Planetary Protection Officer. They have a Planetary Protection Office, and have had one since they were sending probes around their own solar system. Doctor Ma-et had found it a bit silly, like a child concerned about the cleanliness of their toys, until she learned that the job of the Planetary Protection Office had always been protecting other worlds from Earth.