Adopting a cat or dog from an animal shelter or pet rescue can be one of the most rewarding things an animal lover can do. But there’s more to picking out the right pet than simply walking in and falling in love with the first four-legged cutie you meet.

Choosing a pet that is sick can be a costly endeavor to your heart and your wallet. Fox News recently reported on such a situation involving a woman who adopted a dog from an animal shelter in Hot Springs, Arkansas. When Laura Friend brought him home, the dog started vomiting. She took him to the vet and learned her new family member, Lucky, had parvo. Parvo is a common illness, especially if puppies are unvaccinated, but it can be fatal, according to the American Society for Prevention of Cruelty to Animals (ASPCA).

According to the ASPCA, 2.7 million animals are adopted from shelters each year. Here are five questions, courtesy of the Humane Society of the United States, you should ask shelter and rescue workers to make sure the new family member you’re taking home is a healthy one:

1. What type of behavioral assessments are done? Many reputable shelters and rescues set a high bar for assessing an animal’s behavior. They may judge dogs by how well they respond to other dogs, cats and children, for example. Ask how the pet behaved at the shelter, and ask what behaviors you can expect once you get your new dog or cat home.

2. What type of medical evaluations or vaccinations have been done? Many shelters require quarantine for puppies to make sure they aren’t carrying parvo, for example. Shelters may also vaccinate animals. If an animal has a medical condition, ask what kind of treatment is needed and how much it costs.

3. How did the animal arrive at the shelter? Was it a stray? Given up by a previous owner? And if so, why? Ask how long the pet has been at the shelter. These questions can contribute to a greater understanding of an animal’s behavioral and medical history.

4. What is the shelter's spay/neuter policy? Most shelters and rescues have a spay/neuter policy to make sure more unwanted pets aren’t brought into the world. However, policies vary in that some shelters spay/neuter before the animal is put up for adoption, and others require the surgery to be completed within a certain timeframe after the pet goes home. Also, some require a deposit that can be refunded upon the completion of the surgery.

5. What if my pet gets sick after I take it home? Many shelters and rescues offer to take a pet back and provide a full refund if it gets sick within a certain number of days of the adoption. However, returning a pet after all involved have become emotionally attached is hard to do. Ask if the shelter will take on some of the veterinarian costs if this happens.