The common ectoparasites of dogs and cats are fleas, lice, ticks, ear mites, crawling mites and scabies; There are many kinds of parasites in the body, such as roundworms, tapeworms, hookworms and heartworms. Dogs are easily infected with fleas, lice and ticks when they go out every day, and cats who don't go out may also be infected, because we may bring back soles and trouser legs when we go home. The transmission route of heartworm is mosquito bite, which is really hard to prevent. Parasitic infection is very close to us. Once caught, the baby may have itching, skin ulcers, loss of appetite, soft stool, vomiting and other symptoms. Even the most humble flea infection can lead to anemia, malnutrition and even life-threatening. At present, there are many safe and mature parasitic drugs on the market, such as avermectin, praziquantel and albendazole. Instead of spending a lot of money and energy on treatment in severe cases, it is better to take preventive measures in advance and deworm regularly every month, which saves time and money.