Worm Advice

Health Risks to Humans

Parasites don’t just affect your pets. Some have the ability to be transmitted to humans, and some can also carry disease to humans. The term ‘zoonosis’ refers to disease that animals can pass onto humans – many of these zoonotic diseases are contracted through parasites.

In this chapter you will see which parasites can be transmitted to you and the various zoonotic diseases you can get from getting these parasites from your pet. Some are minor, but some can be serious to you and your family’s health, particularly if you live with children, elderly people or the immunosuppressive.

Which of the 15 main parasites mentioned in this guide can humans contract from their pet?

Fleas and flea larvae: Humans can be bitten by fleas from their dogs or cats, and even their rabbits.

Ear mites: It’s not impossible, but people rarely get ear mites from an infected animal.

Lice: Lice are host specific, so the chances of lice on a dog infecting you or another species is unlikely.

Sarcoptic and Demodex mange mites: These mites are able to get into human skin and can pass from your infested pet over to you through direct contact.

Tapeworm: In rare cases, people may be able to ingest tapeworm eggs, but it won’t affect your body in the same way it affects animals. People who pick up tapeworm eggs from pets only have the risk of developing cysts in the tissue of their body.

Roundworm: Getting roundworm is rare, but when it does transmit it can put your health at serious risk, particularly in children, where blindness can occur.

Hookworm: Hookworm affects people only through their skin, normally around the feet, in instances where they have been exposed to infected environments without protective shoes.

Lungworm: Lungworm is known not to pose a risk to people’s health.

Mosquitoes and Heartworm: The mosquitoes infected with heartworm are able to transfer it over to people when biting them, though this isn’t very common.

Whipworm: Whipworm is also known to infect people, but again, this only happens rarely.

Fox lungworm: This parasite is known to not be a risk to humans.

Ticks: Ticks can burrow into human skin and feed from your blood just like they d with cats or dogs, this is why care needs to be taken. They can also carry disease that is able to pass onto humans.

There are also various other parasites, perhaps rarer in existence, that can infect people. Bacterial parasites in particular can carry zoonotic disease to humans and that is why any symptoms from your pet, yourself or those around you will need medical attention.

A lot of these parasites can be avoided. You can dramatically cut the health risks to your pet and to yourself by performing simple steps which will be detailed in the prevention chapter of this guide.

Disease and other health risks from pet parasites

HHPictureThe following are some examples of the health risks humans face from parasites transmitted from their pets. From this you can deduce what precautions to take and how to recognize when a parasite has caused you and your family a health problem. Note: Always seek advice from a doctor if you suspect you have parasites, particularly if symptoms are present.

Lyme’s disease

People can get ticks from a tick-infested pet bringing the ticks into the home environment, but you can also pick them up from the same environments that pets are susceptible to getting them from, e.g. vegetation and wildlife locations, or sometimes even in your own garden.

As with your pet, ticks can attach themselves to your body – just about anywhere! They burrow into your skin and feed on your blood, which will make them engorged after a feed. They are often not always immediately noticeable, as they like to occupy nooks and crannies such as armpits, the scalp or even the groin.

It normally takes well over 24 hours for the Lyme disease bacteria to transfer into your body, but when it does it will end up exhibiting symptoms such as a rash, lethargy, chills, high temperature, muscular pain, body aches, headaches, swelling of the lymph nodes, arthritis, lesions, facial differences and, somewhere, the presence of an attached pea-shaped tick embedded in the skin.

You will need immediate medical attention if you suspect Lyme’s disease. Leaving it too long for treatment can cause more severe symptoms.

Skin conditions


So many parasites can live on or burrow into the skin of pets, and people too, so the risk of developing skin conditions is heightened. Flea bites can irritate the skin, mange mites can affect human skin through close contact with an infected pet, and even the unlikely kind – such as hookworms – can penetrate human skin around the feet and cause problems if you go through affected areas without protective shoes on. Ear mites affect human skin but only in rare instances, and biting lice are much less of a risk due to their host specific nature – e.g. dog lice won’t infect humans or other species of pet in your home, cat lice only infect other cats, etc.


Though rare, this zoonotic infection can be serious due to its risk to children. Roundworms are transmitted to people usually through direct or indirect contact with contaminated animal faeces – children come into the picture because of their likelihood to play in sandpits and soils where infected animals have defecated. Kids being kids, the dirt can end up being ingested when the child puts their hands in their mouth.

Symptoms of toxocariasis can be almost non-existent in many cases as the parasite can die off quickly. When symptoms do occur they can be coughing, fever, abdominal pain and headache. In more severe cases the parasite can reach major organs of the body causing lethargy, poor appetite and, most worryingly, problems with vision and breathing. When left to thrive, the parasite can even cause blindness, which is more likely to occur in children. So, go to the doctors as soon as you suspect anything.

Human echinococcosis

Another zoonotic disease that develops from infection by tapeworms transmitted from an infected animal. This species of tapeworm is called Echinococcus and humans can get it via ingesting its eggs.

Common signs of echinococcosis include cysts, anorexia, general weakness, loss of weight, pain in the abdomen, sickness, chest pain, coughing, shortness of breath – these symptoms vary and depend on how the infection has affected the internal organs, e.g. liver, lungs, eyes, neurological system, muscles, kidneys, bones or brain. This is why the infection can lead to fatality or serious illness if not given medical attention quickly.

Cutaneous larva migrans, Visceral larva migrans and Ocular larva migrans

Cutaneous larva migrans infection involves hookworms that use common pets as hosts and are spread to humans by barefoot exposure on sand or soil containing infected animal faeces. It’s also a strong risk factor for children in sandpits.

This infection is more common in hotter climates, but with travel abroad becoming more and more popular, the infection is getting more and more progressive within Britain.

Signs include skin problems on the feet, toes, hands and sometimes in higher areas of the body. Itching, lesions and tingling are also symptoms. Other skin conditions will need to be ruled out before diagnosis and treatment from a doctor.

HHPicture3Visceral larva migrans is also caused by worms in the faeces of pets and ends up contaminating soil that the person comes into contact with – again, kids playing in sand is a common risk factor. These worms can spread through the body to major organs including lungs, heart, brain, liver or eyes.

Signs include pain in the abdomen, fever, coughing, itchiness, breathlessness, wheezing and problems with the eyes and vision – which can be ocular larva migrans – which is simply when the infection reaches the eyes. Go to your doctor immediately.

Gastrointestinal problems

Gastrointestinal zoonoses are diseases a pet can transfer to their human friend. Some of these are caused by parasites that reside in the intestinal tract, spread around the body or transmit disease causing gastrointestinal symptoms.

Vomiting, diarrhoea, abdominal pain, loss of appetite and other symptoms related to the digestive system are very common symptoms related to zoonotic gastrointestinal problems brought on by parasites.


A spirochete bacteria that is spread to people usually more so from dogs than cats. Symptoms are similar to the flu – chills, muscular pains and aches and headache. Severe cases, however, can be problematic to the major organs causing failure, so medical attention is required immediately.

Bartonellosis or Cat scratch disease


An infection that humans can contract caused by bacteria called Bartonella henselae. Another name for this disease is cat scratch disease. Cats contract the bacteria via fleas or ticks, which can then be contracted by people.

Symptoms range from mild to severe. Usually it is mild, including fever, lethargy, lack of appetite, headaches, swollen glands, sore throat and a pink or red stripey rash. In more severe cases, the disease can spread throughout the body.

Treatment depends on how the disease was spread and by which parasite, but do see your doctor if you suspect you have it.


This disease is caused by an extremely microscopic parasite called Cryptosporidium parvum which is transmitted by ingestion of the parasite present in the infected animal’s faces. You can also contract it by touching your mouth after being in contact with a contaminated object and soil.

Symptoms are not normally present with this disease, but if they do show they are typically diarrhoea, cramps in the stomach, fever and a general stomach ache or upset. More severe cases will have acute diarrhoea and a noticeable loss of weight. Your doctor will be able to prescribe suitable treatments for the symptoms, but there is no outright drug to eliminate the infection.


The majority of warm-blooded creatures are able to be infected with the parasite called Toxoplasma gondii – the culprit that causes toxoplasmosis. Humans are among these creatures.

Though the disease isn’t that widespread in the UK, people are known to pick it up via infected cat faeces. This disease doesn’t always show obvious symptoms in either pet or person, so you may be unaware your pet has it or whether you do.

If signs do show, they are mild and likened to having a cold – fever, aches and sore throat – but symptoms are known to only show in a small percentage of people. Toxoplasmosis is severe only in those with affected immune systems, which can be serious if left untreated. It is also serious and a risk to pregnant women, particularly if the disease is passed onto the baby. Always go to the doctor in these cases.

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