DA2PP Vaccine. This vaccine is generally given as a combination vaccine, sometimes with Leptospirosis, depending on your dog's needs. The 'D' stands for Distemper, which can be a fatal disease in some puppies. Distemper causes a very snotty nose that does not get better with antibiotics. Once your puppy starts having neurological signs such as tremors and seizures, the disease is not curable. The A2 stands for Adenovirus type 2, which is a virus that attacks the liver. The first 'P' stands for Parvovirus, which causes vomiting and diarrhea in puppies and sometimes older dogs. This can be fatal in some cases, even with extensive treatment by your veterinarian, and is a very contagious disease. The Parvo virus can live in the environment for over one year, so you must be careful where you take your puppy before it is protected by the vaccine. The last 'P' stands for Parainfluenza, which is one virus that can cause kennel cough in dogs. Leptospirosis is a bacterial disease that causes kidney failure, is spread by foxes and coyotes, and loves to live in areas with stagnant water, like our river beds in the Paso Robles area. We generally administer this combination vaccine under the skin near the shoulder blades.