There are various intestinal worms that can infect dogs and cats, with hook worms, round worms (ascarids), whip worms (mainly in dogs) and tapeworms being the main groups. Symptoms can include diarrhoea, bloody stools, weight loss, anaemia, pot belly, dry hair and/or general poor appearance. If left untreated, worm infestations can be fatal. Worms can be picked up from the mother (either in utero or via milk), from the environment (infected stools), from eating infected prey (lizard or mouse), or, in the case of tapeworms, from fleas. Worms can also be transmitted to humans.
Safety is also a consideration. In September 2018 the US Food and Drug Administration (FDA) released a statement warning about the risk of tremors and seizures in animals treated with products containing drugs in the isoxazoline class, which are used to combat fleas and ticks. However, the FDA said it still considers the products "safe and effective".
Combination products can be cheaper than buying them separately. On the other hand, it can be difficult to compare the cost of combined products with separates, because it depends on the ingredients (for example, newer and potentially more effective flea treatments are more expensive than older ones) and the cost of supplying what's missing – there's no all-in-one that covers everything. And that's before you take the cost variations from retailer to retailer into account.
To be a successful pet shop owner, manager or employee, you need to be able to sell merchandise, from pet food and toys to cages, fish tanks, leashes and the pets themselves. Obviously you need to know about caring for different animals in order to keep the animals you are selling in good condition; and advise customers on the products they might buy. Some pet shops may be more caring for the animals than others.