Helminths in the dog and cat Certain helminths affecting dogs and cats can cause zoonoses in humans. Tapeworms such as the fox tapeworm (Echinococcus multilocularis) can infect people and can cause severe disease. Roundworms (Toxocara canis, Toxocara cati) and hookworms (Ancylostoma caninum, Ancylostoma tubaeforme) can cause severe disease in puppies or kittens especially in contaminated kennels or catteries, through a vertical, either intrauterine or lactogenic infection. These nematodes can also cause severe disease in children. Whipworms (Trichuris vulpis) can also affect humans and like roundworms, have very resistant eggs and once an infestation has started, it is difficult to eradicate. In order to choose an effective control strategy, it is recommended to perform a risk assessment prior to treatment both for the animal itself as well as for those people who are likely to come into contact with it (children, immunocompromised individuals, etc.). In cases where this type of assessment cannot be performed, regular routine deworming at least four times per year is advised. Deworming at longer intervals proved not to have any effect and did not reduce the parasite population. Despite routine deworming, however, some reinfection is possible. Dogs eating raw meat should be treated every 6 weeks with praziquantel to control tapeworms. If animals are allowed to scavenge, prey on rodents or are hunting dogs, they should be treated monthly with a cesticide. In individual cases, for example where there is a risk of immediate reinfection in a contaminated environment, or when toddlers are present in the household and the animal is allowed to defaecate in the garden, a monthly treatment is recommended to control the risk of zoonotic infections caused by roundworms. Puppies should be first treated at the age of 2 weeks (kittens 3 weeks). The application should be repeated every 2 weeks until weaning to prevent a vertical transmission of both hookworms and roundworms. Dams should be treated towards the end of pregnancy and during lactation with a suitable product to interrupt vertical transmission of roundworms and hookworms when lactating.
