The doctor made it sound easy. Just walk; walk every day. But I couldn’t even make it to the end of our driveway to pick up the mail. A quarter mile there and back. I tried to stand up, but soon got breathless and just stopped. My mailbox looked as if it were in China. I was all of 39 years old, still in the prime of my life, for crying out loud!

A month ago, I was traveling for work or taking care of our 40-acre horse farm in Texas. And for fun, my wife, Stephanie, and I took our horses on narrow paths. Stephanie and I had been in Colorado Springs with friends when I woke up at the middle of the night with discomfort in my chest. Stephanie and I drove to the ER. My 10-day vacation turned into a 10-day hospital stay. My souvenir was a scar from my chest to my belly.

Stephanie had to go to work so she encouraged me to try to take some steps. Minutes later, Stephanie came rushing back, carrying a puppy. “Where did you get that?” I asked. “In our mailbox. What a miracle!” Stephanie replied. “Aren’t I enough of a burden? Do we really need a puppy? We’re no strangers to the homeless. And I can’t take care of myself. How could I babysit this puppy?” I said unhappily.

However, the puppy finally became one of our family members. Wherever I went, he would always follow. I tried to open the door to the yard. It was hard for me and I was a little afraid. Then the puppy ran ahead, looked back and repeated the behavior. He seemed to say “Come on”, encouraging me to go ahead. I took a deep breath, and then a few steps, the puppy right at my side. I succeeded at last. Then we walked. This time, toward the mailbox.

We named him Cheyenne. Before long, I was walking with Cheyenne every day. Pretty soon, I was strong enough to work on the farm again. We had both gotten strong. I always wondered who put a puppy in a mailbox. Nobody was so crazy after all. Finally, it turned out that Cheyenne was what the doctor ordered for me.

Thanks to its harsh environment, Antarctica remained largely untouched by humans for many millennia, allowing a thriving ecosystem to evolve. However, since the 1990s, the last true wilderness on the planet is becoming an increasingly popular destination for adventure-seeking tourists. Now, a new study declares that the visitors may be leaving behind harmful bacteria which could devastate the area's native bird population.

Humans can infect animals with illnesses such as the flu. Researchers, however, believed that the Antarctic animals were immune to the danger due to the continent's extreme weather. However, microbiologist Marta Cerda-Cuellar was not convinced.

She and some colleagues decided to examine waste samples from Antarctic birds for evidence of human bacteria. To ensure the waste was not polluted, the scientists had to collect it from the birds themselves.

The results of their study revealed the presence of several types of human bacteria in the bird waste. This included a common strain (品种) of bacteria that causes food poisoning in humans. The researchers say the bacteria strains were resistant to commonly-used human antibiotics, indicating they were brought in by the visitors, rather than migratory birds (候鸟).

“These strains, which are a common cause for infections in humans and livestock, do not usually cause death outbreaks in wild animals," says Gonzalez-Solis. "However, the emerging or invasive pathogens (病原体) that arrive to highly sensitive populations could have severe consequences and cause the local collapse and extinction of some populations." The researcher also fears the presence of these bugs could foreshadow the arrival of other, more deadly, pathogens as the number of tourists people increases.

Experts believe the only way to prevent the mass destruction of the birds is to impose stricter regulations or, at least, put the ones already in place into effect. For example, while the Antarctica Treaty requires visitors to carry their waste back home to safeguard the pristine environment, the regulation is rarely enforced. Nowadays, some officials are taking steps to save the vulnerable birds before it's too late.