A group of infectious diseases that spread between humans and animals is called zoonotic diseases (also known as zoonoses). These conditions are often caused by bacteria, parasites, viruses, fungi, and prions. People usually get infected this these diseases when they come in contact with infected body fluids, animal bites, drink contaminated water, or eat infected meat.
There are some diseases that may spread only from animals to humans and cannot spread from one person to another. Other conditions (such as Ebola) can spread from animals to humans and then among people, causing outbreaks and health problems. However, there are some conditions that may spread and mutate only in humans (including HIV infection and COVID-19). When the disease spreads in humans only, it is no longer considered a zoonotic disease.
Symptoms
Check below some symptoms that may appear in people with these infectious diseases:
- Fatigue (extreme tiredness)
- Fever
- Headaches
- Body aches
- Rash
- Diarrhea
- Vomiting
If you experience any of the previous symptoms, do not hesitate to see a doctor.
Causes
There are multiple pathogens that often cause zoonoses. For example:
- Bacteria
- Parasites (such as protozoa, parasitic worms, and others)
- Viruses
- Fungi
- Prions
Multiple pathogens can infect only specific organisms (such as humans, specific animals, plants, or even other germs). However, zoonotic diseases can infect both animals and humans. Furthermore, most zoonoses are bacterial, parasitic, or viral. Other zoonotic diseases include ringworm (a fungal infection) and variant Creutzfeldt-Jakob disease (vCJD, also known as “mad cow disease”).
Bacterial Zoonoses
Single-cell organisms that commonly produce and release toxins that cause health problems are called bacteria. Check some examples of bacterial zoonoses below:
- Cat scratch disease
- Lyme disease
- Mycoplasma pneumoniae
- Anthrax
- Brucellosis
- Plague
- Psittacosis
- Q fever
- Salmonella
- Tularemia
- Tuberculosis
Parasitic Zoonoses
In general, there are different parasites, including parasitic worms, protozoa, or ectoparasites (such as lice and mites). Check some parasitic zoonoses below:
- Malaria
- Liver fluke
- Giardiasis
- Echinococcosis (such as hydatid disease)
- Cryptosporidiosis
- Teniasis
- Toxoplasmosis
- Trichinosis
Viral Zoonoses
Small pieces of genetic material that use our cells to produce more copies are called viruses. Check below some viral zoonoses:
- Nipah virus
- Ebola
- Avian influenza (also called bird flu)
- Marburg virus disease
- Mpox
- Rabies
There are several ways you can get a zoonotic disease. Check some examples below:
- Scratches or bites from an infected animal
- Eating raw or undercooked infected meat
- Drinking contaminated water
- Insect bites (these include ticks, mosquitoes, fleas, and others)
- Direct contact with body fluids (such as blood, pee, poop, or saliva) of infected animals
In addition, almost every animal can carry zoonotic conditions. These include:
- Dogs
- Deer
- Cats
- Birds
- Bats
- Livestock (including cows, pigs, and sheep)
- Non-human primates (such as monkeys, apes, and chimpanzees)
- Rodents (such as mice, moles, voles, and rats)
Risk Factors
Generally, there are some factors that could elevate your risk of developing zoonotic diseases. These include:
- Age – Children under the age of 5 and older adults are more prone to zoonotic diseases.
- Weakened immune system – If you have health conditions or follow treatments that weaken the immune system, the risk of developing zoonoses significantly increases.
- Pregnancy – The immunity is often temporarily suppressed during pregnancy, which makes you more likely to develop zoonotic diseases.
- Living, working, or traveling to areas where zoonotic diseases are common also increases the risk of developing them.
What Are The Possible Complications of Zoonotic Diseases?
You may experience some complications along with the diseases themselves, especially without treatment. Check some examples below:
- Neurological or heart problems
- Joint pain
- Severe lung problems
- Kidney failure
- Bloody diarrhea
- Pneumonia
- Hemolytic uremic syndrome (HUS)
- Death
This document does not contain all possible complications of zoonoses. If you suspect you have developed a zoonotic disease complication, immediately contact your doctor. You can also talk with your healthcare provider about ways to reduce the risk or prevent complications.
How to Prevent Zoonotic Diseases?
Check below some tips that may help reduce the risk of developing zoonoses:
- Vaccination – There are multiple health conditions that can be prevented by vaccination. For example, rabies, Ebola, mpox, and others.
- Get protection against bug bites – You should use a bug spray with DEET and wear long pants and a long-sleeved shirt, especially if you live, work, or travel in areas where zoonotic diseases are common.
- Wear gloves when handling animals – You should never pick a wild animal with your bare hands or wash them thoroughly with soap and water after handling them.
- Safe food preparation – You should avoid eating undercooked or raw meat because it may contain bacteria or parasites that cause zoonotic diseases. You should also not drink water from unknown sources.
- Avoid direct contact with infected body fluids – There are some precautions that you should consider to prevent serious health conditions (such as Ebola). It involves protective equipment, including a mask, goggles, an apron, and gloves.
- Do not eat bush meat (it means the meat of wild animals)
Diagnosis
Physicians usually diagnose these infectious diseases by testing a sample of tissue or body fluid, including blood, stool, sputum, or mucus swabbed from the nose or throat. Sometimes, doctors may perform imaging tests such as a chest X-ray or a CT (computerized tomography) scan.
Treatment
Healthcare professionals usually prescribe different treatments for people with zoonotic diseases because it depends on the type and severity of the disease, existing health problems, age, and preferences. Check below the most common treatments used in people who suffer from zoonoses:
- Antibiotics – This is a group of medicines used to treat bacterial infections.
- Antiviral medicines – These medications are prescribed by doctors to treat infections caused by viruses.
- Antifungals – Doctors may recommend antifungal creams or lotions to treat ringworm.
- Antiparasitic medicines – Physicians prescribe these medicines to treat parasitic zoonoses.
- Monoclonal antibodies – There are some health conditions that are difficult to treat (such as Ebola). Therefore, doctors may recommend monoclonal antibodies to treat them.
- Surgery – Sometimes, parasites cause cysts that can be treated with surgery only.
- Vaccination – Several zoonotic diseases can be prevented with vaccines. Discuss with your doctor if you suspect you have a zoonotic disease.
Frequently Asked Questions
Are zoonotic diseases fatal?
There are some zoonoses that may lead to death without treatment. Some of them include viral hemorrhagic fevers (such as Marburg virus and Ebola virus), rabies, and others. However, most zoonotic diseases are treatable.
When should I go to the ER?
It is recommended to go to the nearest emergency room (ER) or call 911 in the U.S. if you experience any of the following symptoms. Examples include:
- Severe diarrhea or vomiting
- High fever (more than 103 degrees F or 40 degrees C)
- Mental health problems (such as confusion)
- Severe headaches
- Unusual bleeding
- Pain in the abdomen or chest
What is the most common zoonotic disease worldwide?
The most common infectious disease is ischemic heart disease, which causes approximately 13% of deaths in the entire world. Ask your healthcare professional if you have any other questions.
