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Veterinary Health Professionals Have Vital Role In Protecting Children From Parasitic Disease

vetreportAugust 2, 2013

At ESCCAP UK and Ireland’s ‘Everyday Parasites’ CPD day, a presentation by parasitologist and counsel chairperson – Maggie Fisher – described a number of studies that have investigated associations between common pet parasite, Toxocara spp. and human disease. Attended by 55 delegates, the seminar highlighted  strong links identified between human infection with the worm and common conditions such as asthma, allergies, learning difficulties and even epilepsy, demonstrating how an ‘everyday’ parasite like Toxocara can have a big impact on  human health. ESCCAP say that vets, nurses and SQPs have a very important role to play in reducing the damaging and widespread effects of Toxocara.

Most veterinary professionals and SQPs are familiar with the Toxocara lifecyle but many may not be aware that Toxocara eggs aren’t actually infective when they are first passed in an animal’s stools, sometimes taking weeks to develop to this stage. Eggs persist long after pet waste has naturally washed away too, so the risk of infection still exists even in environments that appear to be clean and safe. Interestingly, there seems to be only a very loose (and according to some studies, entirely absent) link between owning a pet and an increased risk of human Toxocara infection, suggesting that most infections are acquired from the environment. Education of pet owners about responsible pet ownership, including appropriate worming and picking up their dog’s waste quickly is essential to reduce this environmental infection risk.

The parasite’s larval stages cause disease in humans as they migrate through body tissues, with retinal damage a previously well identified consequence. The studies outlined in Maggie’s presentation identified a whole range of common conditions that may also be attributable to Toxocara infection though. One study included 425 children displaying signs of a persistent cough and 1600 asymptomatic children as controls. Blood tests confirmed that a statistically significant 32% of the symptomatic group were positive for Toxocara antibodies, compared to just 17% of the asymptomatic control group. What’s more, when given a week’s course of an appropriate anthelmintic, the vast majority of symptomatic children had a greatly reduced and frequently absent requirement for inhaled corticosteroids to control their symptoms when re-examined by the study team a year later.

Numerous other studies from around the world have shown similar strong associations with asthma, allergies and epilepsy. One nationally representative US study even showed an alarming association with Toxocara infection and reduced cognitive function in children. Those that were positive for antibodies to the parasite on blood tests (proving prior exposure) scored significantly lower on tests assessing verbal and manual dexterity as well as maths and reading abilities

So, what should veterinary staff and SQPs be telling clients? Advising pet owners to regularly (at least four times a year) worm pets with an effective anthelmintic from an appropriately young age (2 weeks of age for puppies and 3 weeks of age for kittens) is hugely important, remembering that transfer of the parasite to puppies before birth and to kittens via milk is a feature of the parasite lifecycle. Reducing pets’ access to raw food and hunting activities can also help. This is in addition to more general recommendations including cooking food well and making sure children wash their hands before eating. As ESCCAP Chairperson, Maggie made the important point on behalf of the organisation that “vets, nurses and SQPs are perfectly placed to make sure that pet owners are aware of the risks and take precautions to protect themselves and the wider general public.”

For further information about effective control of Toxocara and a wide range of other companion animal parasites, visit www.esccapuk.org.uk. To view all the presentations from the ‘Everyday Parasites’ CPD day, visit www.esccapuk-cpd.co.uk.