Zoonotic diseases in cats can be easily avoided with proper prevention, care
May 01, 2003
Hookworms Hookworms in cats are represented by two species – Ancylostoma tubaeforme and Ancylostoma braziliense. Their prevalence among cats in the United States is virtually unknown. However, we do know their geographic distribution differs within the country. Ancylostoma braziliense is limited to tropical and subtropical regions of the southeastern United States while A. tubaeforme is more generally distributed. The host range for these two parasites also differs in that A. tubaeforme is primarily found in cats while A. braziliense can infect both cats and dogs.
Clinical presentation for these two hookworms differ. The main clinical signs associated with A. tubaeforme infections are weight loss and a regenerative anemia, which goes along with the fact hookworms are blood-feeding parasites. Death can also occur if the rate of larval acquisition is high. Conversely, A. braziliense is less pathogenic with very little hemorrhage at the sites where adults attach. Clinical disease is usually not encounterd.
While A. tubaeforme is more important to the health of the cat, A. braziliense is more important as a cause of cutaneous larval migrans (CLM) in humans. On contact with unprotected skin, L3 penetrate the epidermis. However, the larvae cannot penetrate the basement membrane and are, therefore, confined to the lower epidermis where they migrate aimlessly. As they migrate, the larvae release proteolytic enzymes which leads to an intense inflammatory reaction. Within one to two weeks, the characteristic reddened, serpiginous, and intensely pruritic skin eruptions are visible (Photo 2). Because the inflammatory reaction is not directed against the larvae themselves, the skin eruption tends to be located some distance from where the larvae actually are. Even though CLM is self-limiting, the intense pruritis usually necessitates some treatment to lower the risk of secondary bacterial infections.
Roundworms Roundworms in cats are also represented by two species - Toxascaris leonina and Toxocara cati. Toxascaris leonina is not associated with clinical signs in cats and is rarely zoonotic. Conversely, T. cati is not only zoonotic but is also considered to be the most common and the most important intestinal nematode parasite of cats. Adult T. cati live in the small intestine of the host, producing eggs that are passed with the feces (Photo 3). They are extremely prolific, producing as many as 24,000 eggs per day.
Cats can also be infected through ingestion of rodent paratenic hosts or by transmammary transmission. Larvae acquired by either of these routes do not migrate beyond the intestinal wall and the prepatent period for these infections is about three weeks. Of the three possible routes of infection, transmammary transmission is considered by many to be the most important although ingestion of paratenic hosts may be a primary means by which infections are maintained in cats that are allowed to hunt.