Laurie Anne Walden, DVM![]() Lyme disease is the most common tick-borne disease in humans in the United States.[1] Dogs can be infected with the bacteria that cause Lyme disease but are much less likely than people to develop symptoms. Transmission Lyme disease is caused by infection with Borrelia burgdorferi bacteria, which are transmitted through tick bites. The tick responsible for infection in the eastern United States is Ixodes scapularis, the deer tick (also called the blacklegged tick). Deer ticks persist in the environment because they’re maintained in populations of deer and other wild animals. For this reason, Lyme disease is endemic—always present in the environment—in some parts of the country. Deer ticks are smaller than American dog ticks and can be hard to see on animals with fur. The immature nymph stage, which can also transmit B burgdorferi, is tiny and even harder to spot. Ticks live in woods, grassy areas, and underbrush. Ticks can’t jump or fly; they wait on the tip of a branch or grass blade until a person or animal brushes past, then they latch on. Adult deer ticks can be active when the weather is cool, so Lyme disease isn’t just a summertime risk. Ticks transmit bacteria to the host animal while they’re taking a blood meal. It takes a day or two for B burgdorferi to pass from a tick into a host, so removing ticks within 24 hours reduces the risk of Lyme disease. Humans and dogs don’t spread Lyme disease directly to each other, but dogs can bring ticks into the home. Infection in one host species also means that another host species living in the same environment is at risk. If a dog has a positive test for B burgdorferi, for example, that means the dog has been exposed to ticks carrying the bacteria, and people in the dog’s household are at risk for Lyme disease from the same ticks. Symptoms Most dogs (95%) infected with B burgdorferi don’t develop any symptoms. In dogs that become ill, symptoms start 2 to 5 months after infection and include fever, loss of appetite, and lameness that can shift from one leg to another. Some infected dogs develop kidney disease. Cats can be infected with B burgdorferi, but whether they actually get sick from the infection is unknown. Diagnosis Many dogs are routinely tested for B burgdorferi antibodies at the same time as their annual heartworm test. Antibody tests show whether a dog has been exposed to the bacteria. The American College of Veterinary Internal Medicine recommends yearly antibody tests for all dogs living in or near areas where Lyme disease is endemic.[2] Dogs that test positive have further blood and urine tests to check kidney function and uncover other problems. A positive antibody test in a healthy dog also indicates a possible risk of Lyme disease for people living in the same environment. Diagnosing Lyme disease in dogs with symptoms is not always straightforward. The same symptoms are caused by many different conditions. A positive antibody test means that at some point the dog was bitten by a tick carrying B burgdorferi, not necessarily that the infection is causing the current symptoms. A diagnosis is usually based on antibody test results (possibly more than 1 type of test), symptoms consistent with Lyme disease, lack of evidence of other causes of symptoms, and response to treatment. Treatment Dogs with symptoms of Lyme disease are treated with antibiotics. Dogs that develop kidney disease need additional treatment. Prevention Tick control is the best way to prevent Lyme disease. Many tick preventives are available for dogs; some are given by mouth and others are applied to the skin. Your veterinarian can suggest products best suited to your dog. Some products are available only by prescription. The CDC website has lots of information about preventing tick bites in people and pets. See “Preventing Tick Bites” in the Lyme disease section of the CDC website: https://www.cdc.gov/lyme/prev/index.html Vaccines for Lyme disease are available for dogs. Your veterinarian can advise you on whether you should consider having your dog vaccinated. References 1. Lyme disease. Centers for Disease Control and Prevention. Accessed June 25, 2022. https://www.cdc.gov/lyme/index.html 2. Littman MP, Gerber B, Goldstein RE, Labato MA, Lappin MR, Moore GE. ACVIM consensus update on Lyme borreliosis in dogs and cats. J Vet Intern Med. 2018;32(3):887-903. doi:10.1111/jvim.15085 Ixodes scapularis image source: CDC Laurie Anne Walden, DVM![]() Yeast skin infection (dermatitis) is common in dogs and also affects cats. Animals with allergies to pollen, grass, and other substances are especially prone to yeast dermatitis and yeast ear infections, so watch for the signs of infection if your pet gets itchy when the seasons change. Causes Yeast dermatitis is caused by Malassezia organisms on the skin. Malassezia yeasts are part of the normal collection of microorganisms that live on the skin and in the ears of animals. Yeast dermatitis occurs when something about the host animal—skin condition or immune function—causes Malassezia to overgrow or results in an abnormal immune response to Malassezia organisms. Examples of skin conditions that lead to yeast overgrowth are inflammation and increased moisture. Some animals are allergic to Malassezia and develop yeast dermatitis even when the number of organisms on the skin is relatively low. These are some of the things that increase the risk of yeast dermatitis:
Signs The most commonly affected areas are the face, neck, armpits, belly, inner thighs, feet, and ears, although yeast dermatitis can affect any part of the skin. Yeast dermatitis typically causes these signs:
Diagnosis Samples from affected areas are taken with various methods (tape pressed to the skin, a microscope slide pressed to the skin, cotton swabs, scraping with a blade, or possibly skin biopsy) and examined under a microscope. Animals with yeast dermatitis might have very few Malassezia organisms visible with a microscope. In animals with long-term or recurring yeast dermatitis, other tests are often done to look for an underlying cause. Treatment Yeast dermatitis is treated with topical medication, oral medication, or both. Topical antifungal products include shampoos, mousses, wipes, creams, and so forth. Topical products need enough skin contact time to be effective, so shampoos usually come with instructions not to rinse the lather off for at least 10 minutes. A number of prescription oral antifungal medications are also used. The choice of treatment type—topical, oral, or both—depends on the individual animal, the part of the body affected, the response to earlier treatment, and the ability of the animal’s owner to apply topical treatments. Not everyone has a place to bathe a large shaggy dog twice a week, for instance. Treatment for yeast dermatitis typically needs to continue for weeks. For animals with recurring yeast dermatitis, the underlying cause also needs to be treated. Reference 1. Bond R, Morris DO, Guillot J, et al. Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats clinical consensus guidelines of the World Association for Veterinary Dermatology. Vet Dermatol. 2020;31(1):28-74. doi:10.1111/vde.12809 https://onlinelibrary.wiley.com/doi/10.1111/vde.12809 Public domain image source: CDC/Janice Haney Carr Laurie Anne Walden, DVM![]() As COVID-19 cases increase, more pets are exposed to the virus, so it’s time to review what we know about COVID-19 and animals. The content of this article is current as of February 7, 2022. Can animals get COVID-19? A number of mammal species, including dogs and cats, can be infected with SARS-CoV-2 (the virus that causes COVID-19). Infection in animals is rare compared with infection in people. Most animals infected with the virus have had close contact with people who had COVID-19. Some species have been experimentally infected under controlled conditions; these species might or might not be able to get infected naturally. The virus has not been found in birds, reptiles, amphibians, or fish. Animals infected with SARS-CoV-2 don’t necessarily get sick. Domestic cats, large cats, dogs, ferrets, hamsters, mink, and gorillas have developed symptoms after being infected. Infection with no symptoms has been found in rabbits, bats, white-tailed deer, and many other species. Symptoms of SARS-CoV-2 infection in animals are usually mild and nonspecific (lots of other things cause the same symptoms):
Can pets spread COVID-19 to people or other animals? The risk of catching COVID-19 from a pet is very low. There is no evidence that animals are a significant source of infection for people or that animals carry the virus on their fur. An exception is that SARS-CoV-2 was found to spread in both directions between mink and humans on mink farms in Denmark. Some animals can infect other animals of the same species. For example, SARS-CoV-2 spreads among white-tailed deer populations without causing symptoms. Someone in my household has COVID-19. How should I protect my pets? People with COVID-19 can spread the virus to dogs, cats, and ferrets, although serious illness is rare in animals. The CDC recommends that people with COVID-19 avoid close contact with pets, stay in a room away from pets as much as possible, and wear a mask if they need to be near pets. People carrying the infection should also wash their hands before and after handling animals, avoid sharing food with animals, and avoid kissing their pets or letting their pets lick them in the face. There is no reason to remove pets from the home unless their caregiver is unable to take care of them. Don’t put a mask on an animal or do anything else that might block its airflow. Increase ventilation or use air filters instead. Don’t use hand sanitizer, disinfecting wipes, or surface cleaners on an animal. I think my pet might have COVID-19. What should I do? If your pet has symptoms that seem similar to COVID-19, call your veterinarian. If you have COVID-19, don’t take your pet to the clinic yourself. Your veterinarian will advise you on whether your pet should be seen at the clinic. Can I have my pet tested for COVID-19? Don’t use a home test on an animal. Routine animal testing for COVID-19 is not currently recommended because infection is rare in animals, the symptoms are more likely to be caused by something else, and animals aren’t a significant source of SARS-CoV-2 infection in humans. Decisions about animal testing are made by a veterinarian in consultation with public health officials. A veterinarian will need to rule out more common causes of the symptoms before considering SARS-CoV-2 testing. Testing might be done for animals that meet criteria like having exposure to an infected person and having symptoms compatible with SARS-CoV-2 infection (with no other cause found). Can my pet be vaccinated for COVID-19? Vaccines for dogs and cats are not available. According to the World Organisation for Animal Health, vaccines are being developed for some animal species that are susceptible to SARS-CoV-2 infection. An experimental COVID-19 vaccine has been given to zoo animals at risk of getting sick from the infection. Mink will likely also be a priority species for vaccine development because of their potential to spread the infection to humans. Please see these sources for updates and more information:
Public domain image credit: National Institute of Allergy and Infectious Diseases, NIH. Source: NIH Image Gallery Laurie Anne Walden, DVM![]() 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
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 Laurie Anne Walden, DVM![]() 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:
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:
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 Laurie Anne Walden, DVM ![]() 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.
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.
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:
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:
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:
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) Laurie Anne Walden, DVM ![]() 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:
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 Laurie Anne Walden, DVM ![]() 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:
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:
Emerging Diseases and the Environment The reasons new infectious diseases emerge in humans can be lumped into 3 categories:
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 Laurie Anne Walden, DVM ![]() 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:
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:
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:
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 |
AuthorLaurie Anne Walden, DVM Categories
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June 2022
The contents of this blog are for information only and should not substitute for advice from a veterinarian who has examined the animal. All blog content is copyrighted by Mallard Creek Animal Hospital and may not be copied, reproduced, transmitted, or distributed without permission.
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