Zoonotic ascarids and hookworms : keep them off!


Pets provide many health benefits for people; however, some pets can transmit diseases to people as well. These diseases are called zoonoses but they can be prevented.
Zoonotic diseases are diseases that can be transmitted to people by animals. Broadly, these diseases can be caused by internal parasites, external parasites, fungal infections, and dog and cat bites. The growing popularity of dogs and cats, together with high rates of ascarid and hookworm infections, is leading to widespread contamination of the soil with infective eggs and larvae. Studies have implicated the presence of dogs, particularly puppies, in a household, and pica (dirt eating) as the principal risk factors for human disease. Children’s play habits and their attraction to pets put them at higher risk for infection than adults.
Roundworms : ascarids & hookworms
Your veterinarian might have told number of times that your pet has got worms. So, what are these worms?
The most common types of parasitic worms are ascarids (Toxocara canis, T. cati) and hookworms (Ancylostoma spp.), which are both intestinal parasites. They live and grow inside the intestine of your pet. These worms often infect puppies and kittens as well as older pets. Ascarids and hookworms develop from eggs into larvae (immature worms). The larvae later mature into adult worms. The term “roundworms” is sometimes commonly used to include both ascarids and hookworms.
WWW : Worm Wide Web
Dogs and cats infected with these worms contaminate their surroundings by passing eggs or larvae in their faeces (waste). Since pets can pass faeces anywhere, they may contaminate a large area quickly. These eggs and larvae are resilient and can survive in areas such as parks, playgrounds, and even inside homes.
Ascarids are spread when a person accidentally ingests an infective egg. If we touch the ground or soil that contains the eggs, and then touch our mouth and swallow the eggs, we can get the disease. Ascarids occur primarily in children, who pick up and eat contaminated dirt. Most cases occur because of lack of personal hygiene.
Hookworms are also intestinal parasites of dogs and cats that can cause disease in people. Transmission occurs when the larvae are accidentally ingested. The larvae can also penetrate the skin.
Dogs and cats of any age may get roundworms, but they are most vulnerable when they are very young. In fact, it is not unusual for puppies of only 2-3 weeks of age to harbour a significant number of worms. That’s because these worms are often passed from a mother to her puppies before birth. Sometimes they are passed shortly after birth, through her milk.
During mild infections, most pets show no sign of infection. However, in case of heavy infections, some pets may show signs, which may include vomiting, loss of appetite, or severe weight loss. Heavy infections in young puppies and kittens may be fatal too. Hookworms suck large amounts of blood from their hosts; while infected animals may look healthy in the first week of life, they can develop a rapidly severe, often fatal, anemia.
Diseases in humans
Toxocariasis is a zoonotic (animal to human) infection caused by the parasitic roundworms commonly found in the intestine of dogs (Toxocara canis) and cats (T. cati). The disease is found worldwide, with varying rates from country to country.
Ascarids enter the body when ingested as eggs that soon hatch into larvae. These larvae travel through the liver, lungs, and other organs. In most cases, these “wandering worms” cause no symptoms or apparent damage. However, in some cases they produce a condition known as visceral larva migrans. The larvae may cause damage to tissue and sometimes affect the nerves or even lodge in the eye. In some cases, they may cause permanent nerve or eye damage, even blindness.
Hookworm larvae typically move about within the skin, causing inflammation in the affected skin. This is called cutaneous (skin) larva migrans. One type of hookworm can penetrate into deeper tissues and cause more serious damage to the intestine and other organs.
Protect: your pet, your family & yourself
Seek the help of a veterinarian, who canrecommend treatments to eliminate and help prevent these worm infections. Since these products are available in many forms, you and your vet can choose which one works best for your dog or cat.
Since puppies, kittens, pregnant and nursing animals are at highest risk for these infections, and therefore responsible for most of the environmental contamination and human disease, anthelmintic treatments are most effective when they are initiated early and targeted at these populations.
Prevention involves the control of parasitic infections in your pets with regular testing and the use of dewormers. You should remove dog and cat faeces from the environment on a daily basis. Hookworm eggs can develop into infective stage larvae in the soil in as little as 5 days and ascarid eggs within 2 weeks, depending on temperature and humidity. Once the eggs become infective, they can remain infective in the environment for years. The best way to prevent infection is to wash your hands after handling dog or cat faeces, after gardening, or before eating.
Most pet owners may not know that their pets may carry worms capable of infecting people. Veterinarians due to their access to the pet-owning public, their knowledge and training, can provide an important public service by recommending regular faecal examinations, providing well timed anthelmintic treatments, counselling clients on potential public health hazards, and advising them on any precautionary measures that may be taken.
(Rohit Bhatia is product Manager (Canine) at, Vetnex, RFCL Limited, New Dellhi.)