Zoonotic diseases: How our pets can make us sick
by Charlotte Grainger
Offering companionship and affection, pets are so much more than mere animals. For many of us, these fluffy (or even scaly!) creatures are part of the family. But did you know that your pet could make you sick? Zoonotic diseases are illnesses and infections that can spread from animals to humans. Being aware of them will help you protect yourself and your loved ones. Let’s take a look at 20 examples of these conditions.
Rocky Mountain spotted fever (RMSF)
One of the deadliest tick-borne diseases in the world, Rocky Mountain spotted fever (RMSF) is an illness that causes headaches and fevers. It is often spread by ticks found on dogs with the Rickettsia rickettsii bacteria. Other signs of this illness include sickness, stomach and muscle pain, a lack of appetite, and a rash that appears two to four days after the first sign of fever. Should you believe that you are suffering from this zoonotic disease, see a doctor immediately.
Also known as “tinea” or “dermatophytosis,” ringworm is a fungal infection that can cause a circular rash on the skin. Often, the rash will be itchy or red. You can catch ringworm a number of ways, but one of the most common causes is touching an animal that is infected. It is treated with either prescribed or over-the-counter antifungal medication.
Rabies is highly deadly. When clinical symptoms of this illness appear, the zoonotic disease is almost always fatal. Moreover, in 99% of cases, domestic dogs are the cause of rabies in humans. People generally get infected after suffering a deep bite or scratch from a dog that is carrying the illness. The World Health Organization (WHO) is currently leading the “United Against Rabies” campaign to prevent rabies-caused human deaths by 2030.
Reptiles and amphibians can carry the germ salmonella, which could make you sick. The bacterial infection causes 26,500 hospitalizations and 420 deaths in the United States each year with symptoms including diarrhea, stomach cramps, and a fever. Reptile owners should take care when handling their animals, especially after they have shed their skin.
Cryptococcosis is a rare fungal, zoonotic disease that can be spread to humans through bird droppings, especially pigeons. The infection usually starts in the lungs, causing people bouts of coughing and chest pain. Once diagnosed by a doctor, this illness can be treated with a mixture of antibiotics and antifungal agents including amphotericin B, flucytosine, and fluconazole.
Caused by roundworm parasites, toxocariasis often affects young children. People can get it when they handle soil that has been mixed with dog or cat feces infected with the parasites. Symptoms of the illness include headaches, stomach pain, a cough, and a high temperature above 38ºC (100ºF). In some cases, this illness can cause permanent vision loss, so it’s important to see a doctor as soon as you notice the warning signs.
Cat-scratch disease (CSD)
Cat-scratch disease (CSD) is what it says on the tin. When a cat bites or scratches hard enough to break a person’s skin, or licks an existing open wound, it can become infected with this illness. CSD causes a mild infection to occur around three to 14 days after the bite or scratch. It can cause a fever, headache, and tiredness. Even if serious complications are rare, at any sign of these symptoms, especially in children 5–14 years of age and people with weakened immune systems, you should contact your doctor for a check-up.
“Parrot fever” or psittacosis is a zoonotic disease caused by the Chlamydia psittaci bacteria. It can often infect birds, such as parrots, and in rare cases, be transmitted to humans as well. Once a person is infected, it can cause mild illness or even pneumonia (a lung infection). To lower the risk, bird owners should be vigilant when cleaning and handling their pets.
Often causing skin lesions on the fingers and hands, mycobacterium marinum is caused by bacteria found in a variety of water sources. For that reason, people who work with fish or have home aquariums are at risk of developing the illness. These lesions can heal on their own or persist for months. In rare cases, the infection can cause death in people with weakened immune systems. Should you see the symptoms, contact your doctor.
While usually harmless, toxoplasmosis can cause serious problems in some people, like pregnant women or individuals whose immune system is already weakened. You can catch the infection through contact with feces of infected cats, or infected meat. Many people don’t experience any symptoms or know they have this problem. However, it can cause flu-like side effects, such as tiredness, feeling sick, a sore throat, and swollen glands.
Caused by the bacteria of the Pasteurella genus, pasteurellosis is a zoonotic disease common in many animals, including chickens, cats, dogs, rodents, and livestock. Humans can catch this infection from animal bites, scratches, or licks. If left untreated, the infection can cause meningitis, ocular infections, and respiratory problems. With that in mind, serious animal bites or scratches should always be checked by a medical professional.
With symptoms including diarrhea, stomach cramps, and sickness, campylobacter infection is caused by a common type of bacteria by the same name. Food animals, like poultry, cattle and pigs, as well as “pocket pets,” cats, and dogs can carry this illness. You may become infected if you have contact with the feces of a sick animal. The infection tends to last only a couple of weeks. However, if the symptoms are severe or you have a weak immune system, you may need additional medical help.
Tapeworm is the name given to ribbon-like worms that can live in your guts and intestines. Dogs and cats often host dipylidium caninum, a common type of tapeworm. However, in some cases, humans can also suffer from this problem if they have contact with fleas that harbour the worm eggs. Doctors can treat this parasite with medication.
Lyme disease can start with a tick bite. People suffering from this illness may see a circular rash appear around the location of the original bite within four weeks. Some people also have flu-like symptoms, such as headaches, muscular pain and tiredness. If diagnosed early, Lyme disease can almost always be cured. This zoonotic illness is treated with a course of antibiotics.
Humans can catch giardiasis from contact with soil, food, or water that has been contaminated with a Giardia parasite-infected animal’s feces. Often, these animals will be young, such as puppies or kittens. The illness causes diarrhea, gas, stomach cramps and dehydration. People with this infection may have itchy skin and hives. Fortunately, several drugs can treat this infection. Seek medical help should you notice these signs.
Methicillin-resistant Staphylococcus aureus (MRSA)
Often called a “superbug,” methicillin-resistant Staphylococcus aureus (MRSA) is more often transmitted from human to pet, and rarely the other way around. This illness has few or no symptoms at first. However, as it gets deeper into your skin, it can cause swelling, pain, and pus. If it gets further into your body, the infection can lead to a high temperature, chills, aches and pains, and confusion. Should you have any of these symptoms, speak to a doctor.
Rat-bite fever (RBF)
Joint and muscular pains, vomiting, fevers, and headaches could all be symptoms of rat-bite fever. This zoonotic illness can occur after being in contact with a rodent carrying either Streptobacillus moniliformis or Spirillum minus bacteria. When left untreated, this infection can lead to further issues, such as liver problems, but can also become fatal. Don’t hesitate to contact your doctor.
A major fish pathogen, Streptococcus iniae may also be transmitted to humans. In 2009, the U.S. Centers for Disease Control and Prevention listed this as an emerging infectious disease. People may get infected with this pathogen when handling fish or cleaning out aquariums. There is a more severe risk if you have an open cut or wound while doing so.
Lymphocytic choriomeningitis virus (LCMV)
Often transmitted through the urine, saliva, or droppings of infected rodents, lymphocytic choriomeningitis virus (LCMV) is an illness that can lead to neurological disease and causes a lack of appetite, fever, sickness, and vomiting. In severe cases, the treatment for this condition can require hospitalization. Of course, anyone with symptoms of the illness should speak to a medical professional immediately.
Sarcoptic mange, also known as scabies, is caused by tiny mites and is a parasitic skin disease. Pet dogs can get this disease from contact with other infected animals. While canines do not spread human scabies, the mites that infect them can also affect people. Pet owners who have close contact with dogs should be wary of skin irritations caused by this mite.