Reptiles and amphibians can carry germs that infect humans and other animals. Zoonotic diseases are diseases that spread from animals to humans. Most of the zoonotic diseases of reptiles and amphibians are caused by bacteria.
 
Reptiles and amphibians that carry harmful bacteria often have no symptoms and seem completely normal. If you have a reptile or amphibian pet, assume that it is harboring bacteria and use safe handling practices to keep everyone healthy.
 
Stress, poor nutrition, and an unclean environment increase the chance of a bacterial infection in a reptile or amphibian. Learn all you can about your pet’s husbandry and be sure you’re providing everything it needs: the right food, temperature, humidity, water quality, type and timing of lights, sanitation, and opportunities to engage in normal activities for its species (like climbing, burrowing, or hiding).
 
Salmonella
Salmonella infection is the most common disease that reptiles and amphibians spread to humans. People most often contract salmonellosis from contaminated food but can also be infected through the many animal species that carry Salmonella. With reptiles and amphibians, sources of infection are the animal itself, the animal’s food (including frozen or live rodents), water, habitat (terrarium or tank), and items inside the habitat.
 
Any reptile or amphibian can carry Salmonella. Outbreaks in humans in the last decade have been linked to turtles, bearded dragons, and crested geckos. The risk is especially high with very small turtles, which is why it’s illegal in the United States to sell turtles with shells less than 4 inches long.
 
Humans are infected by getting the bacteria in their mouths, so good hygiene—such as washing hands and keeping habitats clean—helps prevent infection. Symptoms of infection in people include diarrhea, vomiting, cramps, and fever. The risk of severe illness is highest for young children, elderly people, and people with impaired immune systems.
 
Animals that carry Salmonella are often not sick, so they have no symptoms. Reptiles and amphibians that are sick with salmonellosis might have decreased appetite, decreased energy, and diarrhea.
 
Mycobacterium
Mycobacterium bacteria are transmitted through contact with an infected animal or contaminated water. In people, infection causes skin sores and can spread throughout the body, especially in those with weakened immune systems. Reptiles and amphibians carrying Mycobacterium can have no symptoms at all or symptoms related to whichever part of the body the bacteria have infected: skin, lungs, joints, etc.
 
Aeromonas
Aeromonas bacteria live in water and spread through skin wounds or ingestion of contaminated water or other material. Fish, amphibians, and reptiles in aquatic environments can be infected. Symptoms of infection in people include wound infections, vomiting, and diarrhea. As with other types of infection, people with lowered immunity have the highest risk of severe disease. Infected animals can develop discolored limbs, bleeding disorders, and blood infections.
 
Other Bacteria and Parasites
Like all animals, reptiles and amphibians harbor a huge variety of bacteria, some of which could potentially infect humans. Reptiles and amphibians can also be infected with parasites like Giardia and Cryptosporidium that might pose a risk to people.
 
Safe Handling Practices

• Wash your hands after handling reptiles, amphibians, their food, their water, and items in their habitat.
• Don’t kiss your turtle. Or your snake or lizard or frog.
• Don’t bring reptiles, amphibians, or anything from their habitat into areas where human food is prepared.
• Don’t prepare food for your reptile or amphibian in the same place you prepare human food.
• Clean tanks, water bowls, habitat furnishings, and anything else associated with your pet outdoors if possible. If you clean these items indoors, do it somewhere other than the kitchen and disinfect the area afterward.
• Disinfect habitats, water bowls, and so forth with products that are safe for your pet’s species.
• The CDC recommends that children younger than 5 years, elderly people, and people with weakened immune systems not handle reptiles, amphibians, or items from their habitat. If your child has touched a reptile or amphibian, help them wash their hands afterward with soap and water.
• When you’re choosing your pet reptile or amphibian, buy one from a reputable breeder, pet store, or rescue group. Don’t catch a wild animal and keep it as a pet. Don’t buy a small turtle with a shell less than 4 inches long. Consider choosing a different type of pet if someone in your household is at higher risk of serious illness from zoonotic disease (young child, elderly person, or person with impaired immunity).

 
For More Information
See the Reptiles and Amphibians section of the CDC website: https://www.cdc.gov/healthypets/pets/reptiles.html
 
Photo by Vitya Lapatey on Unsplash

Ringworm (dermatophytosis) is a skin infection caused by fungi. It’s called ringworm because in humans it sometimes looks like a small circular skin rash. Ringworm isn’t caused by a worm, despite the name.
 
Ringworm is zoonotic: it spreads between animals and people. Many animal species carry ringworm. The infection is transmitted by contact with an infected host or with contaminated soil, bedding, or other objects in the environment.
 
Causes and Risk Factors
Many types of fungi cause ringworm in different host species (animals and people). The most common fungi that infect cats and dogs are Microsporum canis and Trichophyton mentagrophytes, whose natural hosts are animals, and M gypseum, which is found in soil.
 
Fungi tend to infect abraded skin, not healthy intact skin, so scratches and scrapes—for example, from scratching itchy skin—make ringworm more likely.
 
The pet animals most likely to have ringworm are young puppies and kittens, free-roaming animals, and animals living in warm or humid climates. Working and hunting dogs are more likely than indoor dogs to encounter fungal spores in the environment.[1]
 
Signs of Infection
In dogs and cats, ringworm doesn’t typically cause the ringlike skin lesion that it causes in humans. Ringworm in animals mimics other skin diseases and can’t be diagnosed just by its appearance. Some animals have no visible signs at all. These are some of the signs of ringworm in dogs and cats:

• Hair loss
• Scaly, crusty, or flaky patches of skin
• Pink, red, or darkened patches of skin
• Small red bumps on the skin
• Change in appearance of a toenail (from nail bed infection)

 
Ringworm isn’t usually itchy. However, skin conditions that an animal might have at the same time as ringworm could cause itchy skin, and these conditions can also make a fungal infection more likely.
 
Diagnosis
A combination of diagnostic tests might be needed to confirm a fungal infection and monitor the response to treatment. M canis infection causes hairs to glow fluorescent green under a Wood’s lamp, a type of ultraviolet light source, although the fluorescence can be difficult to see in some patients. Samples collected by plucking hairs or brushing affected skin can be submitted for fungal culture or polymerase chain reaction testing.
 
Treatment
In animals and people with normal immune function, ringworm can clear on its own without treatment, although this can take weeks or months. The goals of treatment are to clear the infection more quickly and prevent the infection from spreading to others.
 
In dogs and cats, treatment often involves both topical treatment and oral medication. Topical treatment (like antifungal shampoos) reduces the risk of disease transmission and environmental contamination. Oral medication treats the fungal infection at its source.
 
Decontaminating an infected animal’s surroundings might be part of the treatment plan. Environmental decontamination prevents false-positive culture results (caused by noninfective fungal spores carried on the fur) that might lengthen the course of treatment.[1]
 
Prevention
These steps help prevent ringworm from spreading to people and other animals:

• If your pet has ringworm, treat it according to your veterinarian’s recommendations and have all other contact animals checked for ringworm.
• Wash your hands with soap after handling animals in general.
• Wear gloves and long sleeves when handling animals with ringworm; wash your hands afterward.
• Do not handle animals with ringworm if you have a compromised immune system.
• To clean the environment of an animal with ringworm, vacuum floors, disinfect hard surfaces, and wash bedding. In areas where bleach is safe to use, 1/4 cup chlorine bleach in 1 gallon of water kills fungal spores.[2]

 
References
1. Moriello KA, Coyner K, Paterson S, Mignon B. Diagnosis and treatment of dermatophytosis in dogs and cats. Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol. 2017;28(3):266-e68. doi:10.1111/vde.12440
2. Ringworm. Centers for Disease Control and Prevention. Accessed September 9, 2021. https://www.cdc.gov/healthypets/diseases/ringworm.html

Image source: CDC Public Health Image Library

Vaccines for dogs and cats are safe, especially compared with the risk of disease. Most animals don’t have any untoward symptoms after receiving a vaccine. But vaccines, like any other medicine, can have some side effects.

Vaccination produces an immune response, and inflammation is part of the immune response. Most of the symptoms (if any) that animals have after vaccination are caused by normal inflammation, meaning that the immune system is acting the way it’s supposed to act when it’s stimulated.

Allergic (hypersensitivity) reactions to vaccines are uncommon in dogs and cats but can be serious. These reactions are caused by an inappropriate immune response. The most severe type of hypersensitivity reaction is anaphylaxis, which can be life threatening.

In one study of dogs in the United States, the rate of vaccine-associated adverse events, including everything from normal inflammatory responses to anaphylaxis, was 0.38% (38 events per 10,000 vaccine doses). Anaphylaxis accounted for 1.7% of the adverse events. The risk of adverse events was highest in small-breed dogs and dogs who received multiple vaccines at the same time.[1]

Mild Symptoms
These are some of the common mild vaccine effects you might notice in your dog or cat. In most cases it’s safe to monitor these symptoms at home. If any of these symptoms last longer than a day or if your pet seems very uncomfortable, contact your veterinarian.

• Mild pain where the vaccine was injected
• Decreased activity or seeming tired
• Loss of appetite
• Sneezing after a vaccine given in the nose

More Serious Symptoms
Allergic reactions to vaccines appear minutes or several hours after vaccination. Anaphylaxis can start with these symptoms and is a medical emergency. Seek veterinary care right away if your pet has any of these symptoms.

• Swelling of the face
• Hives (welts or bumps under the skin, usually itchy)
• Vomiting or diarrhea
• Coughing or difficulty breathing
• Collapse

Lumps at Injection Sites
Most small, firm lumps at vaccine injection sites are caused by inflammation and resolve in a couple of weeks without treatment. An injection-site lump or swelling that is still present after 3 weeks or is enlarging should be checked by a veterinarian. Injection-site cancer is rare but can happen in cats (vaccine protocols and formulations for cats minimize this risk as much as possible).

Autoimmune Disease?
Vaccines could—at least in theory—be linked to autoimmune diseases, in which the immune system targets cells of the body. Immune-mediated hemolytic anemia (affecting red blood cells) and thrombocytopenia (affecting platelets) occur in animals, but the association of these disorders with vaccination isn’t clear.[2] The presence of an autoimmune disease would affect future vaccination decisions for the animal, though.

If Your Pet Has Had a Vaccine Reaction
Tell your veterinarian if your pet has had any vaccine-related symptoms. Your veterinarian will determine if your pet most likely had a normal inflammatory response or an allergic reaction. The decision on how to proceed with future vaccinations depends on the symptoms, the animal’s overall health, and the animal’s individual risk for vaccine-preventable diseases.

Depending on the circumstances, options for future vaccinations might include dividing vaccines among several visits instead of giving multiple vaccines all at once, giving medication (like an antihistamine) before vaccination, using a different type of vaccine, or discontinuing a vaccination. Vaccine titers—levels of antibody in the blood—indicate whether an animal is likely to still be protected by earlier vaccines, so titer testing can replace vaccination in some cases.[3]

Some of these options don’t apply to rabies vaccination, which is mandated by law. In North Carolina and South Carolina, as in many states, veterinarians cannot give medical exemptions for rabies vaccination, and rabies antibody titers can’t be used instead of vaccination.[4]

References
1. Moore GE, Guptill LF, Ward MP, et al. Adverse events diagnosed within three days of vaccine administration in dogs. J Am Vet Med Assoc. 2005;227(7):1102-1108. doi:10.2460/javma.2005.227.1102
2. Tizard IR. Adverse consequences of vaccination. Vaccines for Veterinarians. 2021;115-130.e1. doi:10.1016/B978-0-323-68299-2.00019-8
3. AAHA canine vaccination guidelines: vaccine adverse reactions. American Animal Hospital Association. Accessed August 27, 2021. https://www.aaha.org/aaha-guidelines/vaccination-canine-configuration/frequently-asked-questions/how-can-adverse-reactions-be-managed/
4. Rabiesaware.org. Accessed August 27, 2021. http://www.rabiesaware.org/

Photo by Raghavendra V. Konkathi on Unsplash

In March and April 2021, outbreaks of Salmonella infection linked to wild songbirds, ground turkey, and small turtles were reported, and several brands of dog and cat food were recalled because of possible Salmonella contamination.[1,2]
 
Dogs and cats are at risk of illness from salmonellosis. However, healthy adult animals infected with these bacteria often become carriers with no symptoms. Salmonella are zoonotic—they spread between humans and other animals—so a major concern with Salmonella infection in animals is that it increases the risk for people.
 
Sources
Animal Carriers
Salmonella are spread through the feces of infected animals. These are some of the animals that carry Salmonella and expose people to infection:

• Reptiles and amphibians: turtles, lizards, frogs, etc
• Birds: poultry (chickens, ducks, turkeys, geese), wild songbirds, parrots, etc
• Small mammals: mice, rats, hamsters, etc
• Farm animals: cows, pigs, sheep, etc
• Horses
• Dogs
• Cats[3]

 
Contaminated Food and Water
People and animals are most often infected with Salmonella by eating food or drinking water contaminated with feces. Handling contaminated food is also a risk if you don’t wash your hands thoroughly afterward to avoid bringing the bacteria to your mouth. Potential sources of Salmonella infection in humans, dogs, and cats include the following:

• Raw meat
• Raw meat pet diets
• Pig ears
• Chew hooves
• Dog and cat treats
• Dry dog and cat food
• Vitamins and nutritional products for animals[3,4]

 
Environmental Sources
Animals carrying Salmonella shed the bacteria into their environment. Animals that seem completely healthy can be Salmonella carriers. It’s safest to assume that Salmonella are present anywhere an animal of a high-risk species spends time: reptile habitats, terrariums, aquariums, chicken coops, animal pens, and so forth. Bedding and water tanks or bowls (especially in reptile and amphibian habitats) can also be contaminated.
 
Bird Feeders and Birdbaths
Wild songbirds aren’t just Salmonella carriers; sometimes they get sick and die of Salmonella infection. The type of Salmonella that birds carry, S typhimurium, is contagious to people and other animals. Cats who hunt birds or hang out under bird feeders and birdbaths can be infected.
 
Symptoms
Many adult dogs and cats exposed to Salmonella don’t get sick but can still spread the bacteria. Puppies, kittens, stressed animals, immunosuppressed animals, and animals with other diseases are more likely to become ill with salmonellosis. Symptoms include lethargy, loss of appetite, vomiting, fever, and diarrhea. The infection can be fatal in fetuses and newborns.
 
Salmonellosis in cats infected by birds is called songbird fever. Symptoms are similar to salmonellosis in other animals: vomiting, bloody diarrhea, lethargy, and loss of appetite.
 
Treatment
As with most diseases, specific treatment depends on the individual animal’s needs. Salmonella can develop resistance to antibiotics, so animals with mild symptoms might be treated only with supportive measures. In some cases, the choice of antibiotic is based on results of culture and antimicrobial sensitivity tests.[5]
 
Prevention
Be aware that raw meat pet diets are a common source of Salmonella. The CDC recommends these measures to prevent Salmonella infections:

• Wash hands with soap and water after handling animals, pet food and supplies, bird feeders and birdbaths, and animal feces (even through a plastic bag) and before eating or drinking.
• Clean and disinfect surfaces that have been in contact with animals.
• Clean terrariums and aquariums outdoors, if possible. If you clean one of these items indoors in a tub or sink, disinfect the tub or sink afterward.
• Children under 6 years of age, older people, and people with compromised immunity shouldn’t handle animals that might spread Salmonella (especially reptiles, amphibians, and poultry) or help clean areas where these animals have been. At-risk adults who need to clean animal habitats should wear disposable gloves.
• Don’t eat or drink around animals that might spread Salmonella.
• Keep animals out of food storage and preparation areas.
• Clean and disinfect bird feeders and birdbaths regularly.
• Don’t touch a wild bird with your bare hands.
• Keep pets away from bird feeders and birdbaths.
• If a sick or dead bird is in your yard, remove your bird feeder and birdbath for 2 weeks.
• Contact your state wildlife agency if you find a sick or dead bird. (North Carolina Wildlife Resources Commission: https://www.nc.gov/agency/wildlife-resources-commission)
• If you need to dispose of a dead bird, handle it only with disposable gloves or with a plastic bag over your hand. Place the bird a plastic bag, tie the bag, and throw it away; then wash your hands.[3,6]

 
References
1. Reports of selected Salmonella outbreak investigations. Centers for Disease Control and Prevention. Accessed April 20, 2021. https://www.cdc.gov/salmonella/outbreaks.html
2. Recalls, market withdrawals, & safety alerts. US Food & Drug Administration. Accessed April 20, 2021. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts
3. Salmonella infection. Centers for Disease Control and Prevention. Accessed April 20, 2021. https://www.cdc.gov/healthypets/diseases/salmonella.html
4. Kukanich KS. Update on Salmonella spp contamination of pet food, treats, and nutritional products and safe feeding recommendations. J Am Vet Med Assoc. 2011;238(11):1430-1434. doi:10.2460/javma.238.11.1430
5. Marks SL, Rankin SC, Byrne BA, Weese JS. Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment, and control. J Vet Intern Med. 2011;25(6):1195-1208. doi:10.1111/j.1939-1676.2011.00821.x
6. Salmonella outbreak linked to wild songbirds. Centers for Disease Control and Prevention. April 1, 2021. Accessed April 20, 2021. https://www.cdc.gov/salmonella/typhimurium-04-21/index.html
 
Image source: Shenandoah National Park (photo by N. Lewis, NPS)

Coccidia are tiny parasites that live in the intestines. Coccidia infection is common in dogs and cats, most often affecting puppies and kittens. Infection can cause severe disease and even death, especially in young animals, although some infected animals have no symptoms at all.

Coccidia are protozoa, which are single-celled organisms. They are not worms, and deworming medications do not remove coccidia. Different species of coccidia infect different animals. Coccidia that infect dogs and cats are in the genus Isospora. Other types of coccidia infect other mammals (including humans), birds, fish, reptiles, and amphibians.

Unlike some parasites, coccidia that infect dogs and cats are not contagious to humans. Coccidia are host specific: they cause disease only in their own host species, not in animals of other species. Dogs with coccidia spread the disease to other dogs but not to cats or humans. Cats with coccidia spread the disease only to other cats.

Transmission
Coccidia that infect dogs and cats are transmitted through feces. Dogs and cats are usually infected by swallowing contaminated soil or other contaminated substances in the environment. They can also be infected by eating a small animal (like a rodent or insect) that serves as a transport host or vector for Isospora organisms.

Coccidia in the feces are not infective right away. The life stage that passes out of the body in the stool is immature (nonsporulated). After a few hours in the environment, this stage matures to the sporulated stage, which can infect other animals. Sporulated coccidia can survive in the environment for a year.[1]

Symptoms
After sporulated coccidia are swallowed, they release other stages that invade cells of the intestines. Damage to the intestinal cells is responsible for the symptoms. Puppies, kittens, and adult animals with compromised immune systems are at most risk for serious illness. These are some of the symptoms:

• No symptoms
• Diarrhea
• Weight loss
• Loss of appetite
• Vomiting
• Death (severe cases)

Diagnosis
Coccidia are diagnosed by examining a sample of feces under a microscope. Sometimes infected animals have false-negative test results (no coccidia seen even though the animal is infected), so animals with symptoms might need repeated fecal tests to diagnose the cause of illness. Coccidia can also be found in the feces of animals with no symptoms.

Treatment
Coccidia infection is treated with medication from a veterinarian. Complete treatment may take a few days or a few weeks, depending on the severity of infection. Sanitation of the environment reduces the chance of reinfection during treatment, especially for animals in group housing.
 
Medications that remove hookworms, roundworms, and other common dog and cat parasites do not affect coccidia. Heartworm, flea, and tick preventives also do not remove or prevent coccidia.
 
Prevention
Because coccidia in stool aren’t infective for a few hours, removing feces from the environment regularly (at least once a day) helps prevent infection. Keeping cats indoors reduces or eliminates their exposure risk. Preventing dogs and cats from hunting rodents and other animals also reduces their chance of infection from transport hosts. All dogs and cats—and especially puppies and kittens—should have periodic fecal tests by a veterinarian.
 
Reference
1. Coccidia. Companion Animal Parasite Council. Updated October 1, 2016. Accessed February 19, 2021. https://capcvet.org/guidelines/coccidia/
 
Photo by David Clarke

Zoonotic diseases are diseases transmitted between people and animals. An estimated 75% of emerging infectious diseases in humans have an animal origin.[1] Because people and animals share habitats, environmental health is linked to both human and animal health. Changes in environmental conditions can increase the risk of zoonotic disease spread.
 
One Health is the concept that human, animal, and environmental health are connected and that professionals in all of these areas need to work together to solve global health problems. The COVID-19 pandemic, caused by the zoonotic virus SARS-CoV-2, has highlighted the importance of using a One Health approach to manage emerging diseases.[2]
 
Connections Between Human and Animal Health
COVID-19 is not the first pandemic caused by a zoonotic agent. The Black Death was a bacterial infection spread in part by rat fleas, and the 1918 flu pandemic was caused by an avian influenza virus. The more recent coronavirus epidemics SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) both had animal origins.[2] Many other diseases originating in animals have serious consequences in people. These are just a few examples:

• Rabies
• Anthrax
• Ebola
• HIV/AIDS
• Brucellosis
• Salmonella infection
• H1N1 swine influenza

 
People spread pathogens to animals too. For example, humans can transmit SARS-CoV-2 to companion animals like cats and dogs. Some infectious agents (bacteria, for instance) move in both directions between humans and nonhuman animals. Contaminated water endangers people and animals alike.
 
Cross-species disease transmission is not necessarily direct. In some cases, viruses circulating in an animal population undergo genetic changes and are then able to infect a new species. Some pathogens spread from one species to another through multiple intermediate host species. Others require vectors—carriers like mosquitoes—to infect new hosts.
 
The One Health approach recognizes multiple factors that can influence disease spread:

• Expansion of humans into new geographic areas, encroaching on wildlife habitats
• Close contact between humans and livestock
• Shared living spaces for humans and companion animals
• Increased travel and trade, allowing pathogens to move worldwide
• Antimicrobial resistance, which endangers animal health, human health, and the food supply
• Contamination of the environment
• Deforestation and habitat disruption through inappropriate farming practices
• Effects of climate change on animal populations and ecosystems[3]

 
Emerging Diseases and the Environment
The reasons new infectious diseases emerge in humans can be lumped into 3 categories:

• Changes in the pathogen, such as a virus mutating
• Host factors: individual factors (like immune function) and population factors (like crowding behavior and population growth)
  
• Environmental changes, mostly caused by human behavior[4]

 
Climate change and extreme weather affect the movement of wildlife that carry zoonotic diseases. The geographic spread of some vector-borne diseases has increased as climate change (warming) expands the range of the insects that transmit them.[3] Any human behavior that increases human contact with wildlife (like legal or illegal wildlife trade), decreases natural habitats, alters ecosystems, or reduces species diversity can increase the risk of zoonotic disease spread.
 
International Collaboration
A number of agencies worldwide are involved in One Health collaborations. In the United States, the One Health Office is located in the National Center for Emerging and Zoonotic Infectious Diseases, part of the Centers for Disease Control and Prevention. The World Health Organization, Food and Agriculture Organization of the United Nations, and World Organisation for Animal Health work together to develop global health strategies. Many other organizations are collaborating across disciplines to study and manage zoonotic diseases.
 
References
1. Zoonotic diseases. Centers for Disease Control and Prevention. Accessed November 3, 2020. https://www.cdc.gov/onehealth/basics/zoonotic-diseases.html
2. Deem SL, Brenn-White M. One Health—the key to preventing COVID-19 from becoming the new normal. Mol Front J. Published online September 30, 2020. doi:10.1142/S2529732520400039
3. One Health basics. Centers for Disease Control and Prevention. Accessed November 3, 2020. https://www.cdc.gov/onehealth/basics/index.html
4. Morens DM, Fauci AS. Emerging pandemic diseases: how we got to COVID-19. Cell. 2020;182(5):1077-1092. doi:10.1016/j.cell.2020.08.021
 
Image source: Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases

Six months after my first blog post about coronavirus disease 2019 (COVID-19) and pets, it’s time for another look at what we know about the disease. The information in this article is current on October 2, 2020. For updates and more information, please see these resources:

• World Organisation for Animal Health (OIE): https://www.oie.int/en/scientific-expertise/specific-information-and-recommendations/questions-and-answers-on-2019novel-coronavirus/
• Centers for Disease Control and Prevention (CDC): https://www.cdc.gov/coronavirus/2019-ncov/animals/pets-other-animals.html
• World Health Organization (WHO): https://www.who.int/emergencies/diseases/novel-coronavirus-2019/question-and-answers-hub/q-a-detail/q-a-coronaviruses
• American Veterinary Medical Association (AVMA): https://www.avma.org/resources-tools/animal-health-and-welfare/covid-19
  

Can pets get sick with COVID-19?
Infection is possible but rare in animals. Cats seem to be at higher risk than other companion animals.

Over the last several months, a few animals have had positive tests for SARS-CoV-2, the virus that causes COVID-19, after contact with people who were known or suspected to be carrying the virus. The virus has been identified in domestic cats, large cats, mink, and dogs. A positive virus test doesn’t necessarily mean that an animal will get sick or will be able to transmit the virus to other animals.

According to the OIE, cats and farmed mink have developed disease symptoms after being infected naturally (not in a laboratory). Cats have had respiratory and digestive tract symptoms, and mink have had respiratory disease and a higher death rate.

In laboratory studies, cats, ferrets, golden Syrian hamsters, some nonhuman primates, dogs, and fruit bats have been infected. In the laboratory, cats, ferrets, and fruit bats were able to transmit the infection to other animals of the same species. Whether animal-to-animal transmission happens in animals’ natural environments is not yet clear.

Can pets give COVID-19 to people?
There is still no evidence, after infections in millions of people, that companion animals spread the infection to humans. “The current pandemic is being sustained through human to human transmission of SARS-CoV-2,” writes the OIE. There have also been no reports of the virus being spread by contact with animal hair or accessories like leashes.

The virus probably arose from an animal species (possibly bats), but we don’t yet know the exact source, route of transmission to humans, or whether intermediate host species were involved.

How should I protect my pets during the pandemic?
The OIE, CDC, WHO, and AVMA all have similar recommendations for pet owners during the pandemic:

• Use hygiene measures like washing your hands before and after handling animals, animal food, and animal supplies.
• Don’t kiss animals, let them lick you, or share food with them.
• Keep cats indoors to minimize their exposure risk.
• Avoid large gatherings with your pets.
• When walking dogs, keep them on leash and stay at least 6 feet away from other people.
• For service animals that must go into public areas, clean and disinfect collars, vests, leashes, and other supplies regularly.
• Have backup caregivers lined up and an emergency kit ready in case you get sick. Here’s a printable COVID-19 pet preparedness checklist from Charlotte-Mecklenburg Animal Care & Control and Humane Society of Charlotte: https://charlottenc.gov/AnimalsCMPD/PetSafety/Documents/covid%20preparedness.pdf  
• Do not use household disinfectants on animals.
• Don’t put a mask on an animal. Masks are a suffocation risk for animals.

The CDC guidance for handlers of service and therapy animals is available here: https://www.cdc.gov/coronavirus/2019-ncov/animals/service-therapy-animals.html

If I have COVID-19, what should I do with my pets?
Recommendations for people with confirmed or suspected infection include the following:

• Minimize your contact with animals, especially species known to be susceptible to infection.
• Have someone else in your household care for your pets if possible.
• If you must care for your pets yourself, wear a mask and use good hygiene practices.
• Keep your pets away from people who are not in your household during your quarantine.
• If your pet is sick, call your veterinary clinic. Tell the clinic you have (or might have) COVID-19. If your pet needs to go the clinic, have someone else transport your pet; do not go yourself.
• It’s best to keep your pets in your own household or with your backup caregivers while you’re quarantining. There is no need to give up or abandon them because you have COVID-19. If you can’t care for them while you’re sick, contact local animal control services to see if temporary animal sheltering is available.

Should my pet be tested for the COVID-19 virus?
Current guidance from the CDC and the North Carolina Division of Public Health does not recommend routinely testing animals for SARS-CoV-2. Veterinarians are asked to rule out more common causes of the symptoms before considering COVID-19 testing. In North Carolina, the decision to approve testing in an animal is made in collaboration with state public health officials. Animals approved for testing must meet certain criteria, like having possible exposure to SARS-CoV-2, compatible clinical signs, and no evidence of another cause of the symptoms.

Image: Creative rendition of SARS-COV-2 virus particles (not to scale). Credit: National Institute of Allergy and Infectious Diseases, National Institutes of Health

Feline infectious peritonitis (FIP) is a serious disease caused by a coronavirus infection in cats. The disease is usually fatal, although a new antiviral drug under investigation has had promising results in some cats.
 
Cause
Cats very commonly carry a strain of feline coronavirus that lives in cells of the intestines. This virus, feline enteric coronavirus, does not cause disease in most cats. In some cats, though, the virus mutates into a disease-causing strain that invades a type of white blood cell and spreads through the body. This strain is FIP virus (FIPV). The disease it causes, FIP, results from the body’s immune response to the infection.
 
Transmission
Feline enteric coronavirus spreads easily among cats housed together, especially in shelters and catteries. This virus is shed in the feces, and cats can be infected if they share litter boxes or have close contact with infected cats. Cats with no symptoms can spread the virus to other cats. Cats are often exposed to feline enteric coronavirus as young kittens.
 
Why feline enteric coronavirus mutates into FIPV in some cats is not fully known. Virus genetics and individual cat factors (genetics, immune function, and possibly environment) are likely to be involved. Most cats that develop FIP are kittens or young adults. Cats housed in groups, male cats, purebred cats, and cats that have not been spayed or neutered are at higher risk than others for FIP.[1,2]
 
The mutated virus strain, FIPV, does not appear to spread directly from cat to cat. Feline enteric coronavirus and FIPV are not known to infect humans.
 
Symptoms
Most cats exposed to feline enteric coronavirus do not become ill. Some cats have an episode of diarrhea or vomiting, which is usually mild.
 
Because FIPV spreads throughout the body, FIP affects many body systems and can cause a wide range of symptoms. The clinical signs are not specific; they can be caused by diseases other than FIP.
 
Typical FIP signs are caused by fluid accumulation in the abdomen and chest, by inflammatory changes in various parts of the body (such as kidneys, nervous system, liver, heart, or eyes), or both. The symptoms depend on the body system affected and can change over time in the same cat. These are some of the possible symptoms of FIP:

• Loss of appetite
• Weight loss
• Fever
• Decreased energy
• Swollen belly
• Labored or open-mouth breathing
• Stumbling or loss of balance
• Tremors or seizures

 
Diagnosis
Diagnosing FIP is not straightforward and can’t currently be done with a simple blood test. Because so many cats have been exposed to feline enteric coronavirus, a positive antibody test (indicating virus exposure) doesn’t mean that a sick cat has FIP. The diagnosis is usually based on a combination of clinical signs, results of baseline blood and urine tests, and analysis of abdominal fluid and samples taken from affected organs.
 
Treatment
Until recently, the prognosis for cats with FIP was uniformly bleak. Conventional treatments, including various antiviral medications and drugs to manage the immune response, have had variable success at prolonging cats’ survival times. Cats are usually treated with supportive measures to maximize their comfort for as long as possible.
 
A new antiviral drug, GS-441524, successfully treated some cats with FIP in a study published in 2019.[3] This drug is closely related to remdesivir, which was originally developed as a treatment for Ebola virus infection and is now being studied as a potential treatment for coronavirus disease 2019. GS-441524 may prove to be effective for some cases of FIP, but it is not currently approved by the US Food and Drug Administration.
 
Prevention
Preventing FIP is difficult because feline enteric coronavirus spreads so easily among cats and because the factors that cause it to mutate to FIPV aren’t known. A vaccine for FIP has been marketed, but it is not very effective and is not currently recommended for use in cats.[4] Practicing good husbandry in high-density environments like shelters and keeping individual cats in good health might reduce the risk.
 
References
1. Levy JK, Hutsell S. Overview of feline infectious peritonitis. Merck Veterinary Manual. Updated January 2014. Accessed May 6, 2020. https://www.merckvetmanual.com/generalized-conditions/feline-infectious-peritonitis/overview-of-feline-infectious-peritonitis
2. Felten S, Hartmann K. Diagnosis of feline infectious peritonitis: a review of the current literature. Viruses. 2019;11(11):1068. doi:10.3390/v11111068
3. Pedersen NC, Perron M, Bannasch M, et al. Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis. J Feline Med Surg. 2019;21(4):271‐281. doi:10.1177/1098612X19825701
4. Scherk MA, Ford RB, Gaskell RM, et al. 2013 AAFP Feline Vaccination Advisory Panel Report. J Feline Med Surg. 2013;15(9):785‐808. Published corrections appear in J Feline Med Surg. 2013;15(11):NP2 and J Feline Med Surg. 2014;16(1):66. doi:10.1177/1098612X13500429
 
Photo by Timothy Warrington

New information about coronavirus disease 2019 (COVID-19) continues to emerge as the pandemic progresses. The information in this article is current on the date of posting (April 1, 2020). For the most recent updates, see the resources linked at the end of the article.
 
Can pets get sick with COVID-19?
This question is still being investigated. A vast number of pets have lived with people with COVID-19 without getting sick, so the risk of human-to-animal transmission is probably extremely low. The Centers for Disease Control and Prevention (CDC) has not had any reports of animals in the United States getting sick with COVID-19.
 
There have been rare reports of pets in other countries having positive tests for SARS-CoV-2, the virus that causes COVID-19. (A positive test for a virus doesn’t necessarily mean the virus will cause illness in that animal. It also doesn’t show whether the animal can pass the virus to another animal.) These animals each lived with a person with confirmed COVID-19 and were almost certainly exposed by the infected person. Two dogs in Hong Kong had positive tests for SARS-CoV-2 but had no symptoms (they didn’t actually get sick with COVID-19). One cat in Belgium reportedly had a positive test and symptoms, but because of missing or questionable evidence about this cat, the World Organisation for Animal Health has not confirmed this as an infection.
 
Can pets spread COVID-19 to people?
Multiple infectious disease experts and international health organizations say there is currently no evidence that dogs and cats can spread the COVID-19 virus to people.
 
There is no need to avoid, neglect, or surrender pets out of fear of COVID-19. (This has reportedly been happening in some places.)
 
Pets and people live in close contact and can share other diseases, so health organizations recommend washing your hands after handling animals and practicing good hygiene in general.
 
Can pet hair or accessories (leashes, food bowls, etc) transmit the COVID-19 virus to people?
According to the most recent data and guidance, transmission through pet accessories is theoretically possible but hasn’t been shown to actually happen. SARS-CoV-2 mainly spreads from person to person. Touching an object that has virus particles on it and then touching your face could possibly transmit the virus, but this route is not considered a major source of infection.
 
If the virus can be transmitted through pet hair or accessories at all, transmission is probably more likely with smooth, solid objects like food bowls than with porous or fibrous objects like hair. Coronaviruses can stay on surfaces for hours or days, according to the World Health Organization. The virus particles might or might not be able to infect a person during that whole time, depending on the environmental conditions.
 
Although it seems unlikely that the virus would be transmitted by a leash, food bowl, or pet hair, it’s always a good idea to clean pet accessories regularly and wash your hands after handling an animal.
 
If someone in my household has COVID-19, how should I protect my pets?
The CDC recommends that people who have COVID-19 stay separated from pets. CDC guidance states that people with COVID-19 should “avoid direct contact with pets, including petting, snuggling, being kissed or licked, sleeping in the same location, and sharing food.” This guidance does not apply to service animals, who can stay with their handlers.
 
If possible, someone who does not have COVID-19 should take over the pet care. People with COVID-19 who have to continue caring for their pets (including service animals) should wash their hands before and after handling their pets. The American Veterinary Medical Association adds that people with COVID-19 should wear a face mask around their animals and shouldn’t share food, dishes, or bedding with them.
 
No one is recommending that pets wear face masks, in case you were wondering. Face masks could actually harm animals by hindering their breathing.
 
How should I prepare for pet care in case I get sick with COVID-19?
Plan ahead, just as you prepare for natural disasters like hurricanes. Identify someone who can take care of your pets if you’re unable to. Make sure you have a couple of weeks’ worth of pet food and medications. Check your supply of monthly heartworm and flea preventives and contact your veterinarian if you need a refill. If your pet has medical needs, be ready to provide a list of instructions for another caregiver. Consider preparing a letter for your veterinarian authorizing your backup caregiver to approve treatments.
 
If my pet needs to see a veterinarian, what should I do?
Contact your veterinarian to find out if your pet should go the clinic. Depending on local guidance, the clinic might be postponing non-urgent procedures to help reduce community spread of COVID-19. Some clinics might be able to treat established patients through telemedicine (virtual visits).
 
Under North Carolina’s current stay-at-home order, veterinary clinics are considered essential businesses. Your pets can still get the care they need. If your pet needs to be seen at the clinic, you will probably be asked to stay outside the building while your pet is taken inside to help keep you and the clinic staff safe.
 
If I am (or might be) sick with COVID-19 and my pet needs to see a veterinarian, what should I do?
Call the clinic. Your clinic might not have sufficient personal protective equipment for staff to use when handling animals from a household with COVID-19. Your veterinarian might be able to treat your pet via telemedicine or refer you to a clinic with available protective equipment. If your veterinarian confirms that your pet should come to the clinic, have someone else (ideally not living in your household) transport your pet to the clinic.
 
For more information and updates:

• American Veterinary Medical Association: https://www.avma.org/resources-tools/animal-health-and-welfare/covid-19
• CDC: https://www.cdc.gov/coronavirus/2019-nCoV/index.html
• World Health Organization: https://www.who.int/emergencies/diseases/novel-coronavirus-2019
• World Organisation for Animal Health: https://www.oie.int/en/scientific-expertise/specific-information-and-recommendations/questions-and-answers-on-2019novel-coronavirus/

 
Image: colorized scanning electron micrograph of cell infected with SARS-CoV. Credit: National Institute of Allergy and Infectious Diseases, NIH; https://www.flickr.com/photos/nihgov/49680300342/.

Coronaviruses cause disease in many animal species. Most coronaviruses affect either the respiratory tract or the digestive system. Some coronaviruses cause no symptoms or only mild illnesses like the common cold. Others cause serious disease.
 
New information continues to emerge about SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). At this time (early March 2020), there is no evidence that this virus can spread between humans and companion animals like dogs and cats.
 
For updated information about COVID-19, see these resources:

• Centers for Disease Control and Prevention: https://www.cdc.gov/coronavirus/2019-ncov/index.html
• World Health Organization: https://www.who.int/emergencies/diseases/novel-coronavirus-2019
• World Organisation for Animal Health: https://www.oie.int/en/scientific-expertise/specific-information-and-recommendations/questions-and-answers-on-2019novel-coronavirus/

 
Coronaviruses got their name from spike proteins that cover the surface of the virus particles and look like a crown (corona in Latin) on electron microscopy images. Coronavirus spike proteins bind to receptors on the host animal’s cells and allow the virus particles to fuse with the cells. Spike proteins and the receptors they target vary according to the type of coronavirus.
 
Because animal species don’t all have the same molecular receptors and different coronaviruses have different surface proteins, coronaviruses tend to be species specific. A coronavirus that causes disease in cows, for example, doesn’t normally cause disease in cats. This is also why your dogs don’t catch your cold even if you sneeze in their faces.
 
Some coronaviruses are zoonotic, meaning they can be transmitted between animals and humans. Coronaviruses jump to a new host species through genetic mutation. Mutation changes the virus proteins and creates a genetically different coronavirus that can infect a different host. Jumping to a new species might also be easier if the molecular receptors in the new host species are similar to those of the original host species.
 
Coronavirus infections in livestock and companion animals can be severe. However, until 2002, coronaviruses usually caused only mild disease in people with fully functioning immune systems. In 2002, an outbreak of severe acute respiratory syndrome (SARS) occurred in China, and in 2012, Middle East respiratory syndrome (MERS) emerged. Both of these outbreaks were caused by coronaviruses thought to have begun as bat viruses. Bats and people don’t have much contact, so the viruses that caused SARS and MERS spread to people through intermediate hosts: civets for SARS and camels for MERS.[1] COVID-19 is the third coronavirus disease to cause serious outcomes in humans.[2]
 
Animal Diseases Caused by Coronaviruses
Diseases caused by coronaviruses have been identified in many mammal and bird species. Some examples of coronaviruses that cause serious disease in livestock are transmissible gastroenteritis virus and porcine epidemic diarrhea virus in piglets, infectious bronchitis virus in chickens, and bovine coronavirus in cows.[3]
 
The coronaviruses of most concern in cats and dogs are feline coronavirus, canine coronavirus, and canine respiratory coronavirus. Feline coronavirus usually causes such mild symptoms they aren’t noticed at all. In some cats, though, infection leads to feline infectious peritonitis, a devastating disease that is nearly always fatal. (Feline infectious peritonitis will be covered in more detail in another article.) Canine coronavirus is passed through the feces and causes vomiting and diarrhea, especially in groups of dogs in kennels and animal shelters. Infection usually carries a low risk of death, but a more severe strain of canine coronavirus can be fatal to dogs.[4] Canine respiratory coronavirus is one of the causes of canine infectious respiratory disease (kennel cough).
 
The emergence of SARS and MERS in humans prompted more research into coronaviruses, so new therapies for coronavirus diseases may be available in the future.
 
References
1. Cui J, Li F, Shi ZL. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbiol. 2019;17(3):181-192.
2. Coronaviruses. National Institute of Allergy and Infectious Diseases website. Updated March 2, 2020. Accessed March 5, 2020. https://www.niaid.nih.gov/diseases-conditions/coronaviruses
3. Fehr AR, Perlman S. Coronaviruses: an overview of their replication and pathogenesis. Methods Mol Biol. 2015;1282:1-23.
4. Decaro N, Buonavoglia C. Canine coronavirus: not only an enteric pathogen. Vet Clin North Am Small Anim Pract. 2011;41(6):1121-1132.

Image source: https://phil.cdc.gov/Details.aspx?pid=15523