Published on February 4th, 2019 | by Debbie Martin
Although most pet owners are vigilant about the need for worm control for their dogs, vets are still saying that the danger of Toxocara Canis to dogs and humans is still prevalent worldwide.
Infection from Toxocara Canis (roundworm) and Toxocara cati larvae is possible when eggs or larvae are ingested. These can be deposited in the faeces of dogs and cats. Infection is generally more commonly seen in cats and particularly in cats that regularly hunt for rodents and birds which can be hosts for roundworm larvae. It is said that adult dogs are primarily responsible for the production of infected faeces especially in towns, cities and domestic gardens and a figure of 1 billion Toxocara eggs contained within those faeces has been discussed. It has to be said that most faeces are removed straightaway or soon after being deposited so that eggs do not get the chance to spread into the environment. However, there are still areas where this does not occur and soil samples taken from areas like public parks will show the presence of Toxocara eggs.
The Danger to Humans
When humans accidentally ingest the eggs or larvae it is possible to become infected by Toxocara. One scare story which has over time resulted in persuading dog owners to pick up after their pets have defecated is the one about a child becoming infected and blinded after playing in a play area sandpit. Although this is a rare scenario, the implication is that direct contact with dog or cat faeces can have drastic consequences for human health. In fact, it is assumed that the effects of infection by this particular parasite are probably underestimated.
Undiagnosed infection in humans is quite common as the symptoms and presentations of certain illnesses would not be initially associated with Toxocara. Doctors who deal with patients showing evidence of some neurological, dermatological or systemic symptoms would more than likely explore other options for diagnosis. There have been case reports which indicated the presence of anti-Toxocara antibodies in people who present with diseases as diverse as asthma, epilepsy and impaired brain development. Indeed, some studies in the US found reduced ability in cognitive tests in people known to have come into contact with Toxocara.
How We Can Help in The Fight Against Toxocara
The most enlightened dog and cat owners are aware of how important it is to worm their pets regularly and clear up after them but judging by readily accessible reports and figures regarding Toxocara infection it seems that not all are doing the right thing. Local authorities around the UK regularly produce figures indicating how widespread is the refusal to pick up their pet’s faeces in public places.
In The Community
Whilst local councils are doing their bit to educate dog owners about the dangers and consequences of not clearing up dog faeces vets can also play their part through engaging with schools and with social media campaigns to get the message to as many of the population as possible. Engagement with communities has been shown to produce good results in helping to change pet owner behaviour. The reduction in dog fouling allied with a campaign of preventive worming treatments recommended to pet owners is the best way to drastically reduce the incidence of Toxocara infection. Cat owners can also be reminded of the need to prevent Toxocara cati infection and the danger posed to health by clearing away cat faeces wherever possible.
The Fight Against Toxocara Starts Early
Pregnant bitches and queens can carry latent roundworm larvae which can cross the placenta (in dogs only) and into the milk (both dogs and cats) to infect unborn kittens and puppies. This can result in distressing fluid accumulations, respiratory difficulties and sometimes obstruction in the gut and because newborn and very young animals are less able to fight off infection there is very good cause for vets to press upon owners the importance of early worming. The presence of larvae can also lead to a dam showing signs of infestation and egg shedding so vigilance must be shown with regard to worming her.
Puppies must be wormed at two weeks of age then every two weeks up to twelve weeks of age. Kittens should be wormed at three weeks of age and thereafter on an equally regular basis up to the age of six months. Even so, egg shedding can begin early, often before the first consultation with a vet so breeders and owners of new pups and kittens should be contacted as early as possible.
Regular worming should not end when an animal reaches adulthood as egg shedding can occur at any time particularly with animals that hunt and scavenge or come into contact with wildlife. It is recommended that adult dogs and cats are treated with a wormer appropriate for their age and every month in order to be effective against repeated infestations. Monthly worming will completely eliminate egg shedding whereas twice yearly treatment has little or no impact at all. Worming every three months will eliminate some but not all egg shedding and does not eliminate the risk of patent infections.