Laurie Anne Walden, DVM Cyclospora cayetanensis organisms in a stool sample. Public domain image from CDC/DPDx - Melanie Moser. Human outbreaks of diarrhea caused by cyclosporiasis have been reported across the United States this summer. Hundreds of cases have been reported in North Carolina. Most of these have been in Wake County, but some have also been reported in Mecklenburg County.
Cyclosporiasis is a human disease. This disease doesn’t affect dogs and cats, although similar intestinal infections cause diarrhea and vomiting in animals. No cases of cyclosporiasis in humans have been linked to animal transmission. Still, it’s best to practice good hand hygiene and dispose of animal waste properly; other parasites that are common in animals can infect people. Cause Cyclosporiasis is caused by infection with Cyclospora cayetanensis, a protozoan parasite. Cyclospora are types of coccidia, so they’re related to the coccidia that infect dogs, cats, and other animals. Coccidia are host specific: each species of coccidia typically infects only one host species. Humans are the host species for C cayetanensis. How Cyclosporiasis Spreads Cyclosporiasis spreads through contaminated food and water. Cyclospora organisms that are passed in human feces enter the environment, where they develop into a form that can infect other people. The organisms aren’t spread directly from person to person; they need a week or two in the environment to become infectious. The most common sources of infection are fresh vegetables and fruits. We don’t yet know all of the sources of this summer’s outbreaks. Iceberg lettuce from one supplier has been recalled so far. Signs in People
Treatment and Prevention Like coccidia infections in animals, cyclosporiasis in people is treated with antibiotics. In some people, the illness improves without treatment. The US Food and Drug Administration recommends these steps:
Precautions With Pets Seek veterinary care if your pet has diarrhea that lasts longer than a couple of days or if your pet has other signs like vomiting, belly pain, or loss of appetite. Dogs and cats are very unlikely to be infected with C cayetanensis. Pets that eat fresh produce—guinea pigs, other rodents, and reptiles, for example—are also not host species for this parasite and have not been found to be at risk of infection. However, lots of other infections cause diarrhea in animals. Animals have not been shown to transmit cyclosporiasis to people. Cyclospora organisms have been detected in the feces of dogs that swallowed the organisms, but whether these organisms can actually infect people is unclear. Animals carry many other infectious organisms that can make people sick, so use general precautions: wash hands before eating and after handling animals or their feces, pick up your dog’s stool and dispose of it properly, disinfect surfaces in contact with animal feces, and give your pets the parasite prevention products that your veterinarian recommends. For More Information
Image source: https://wwwn.cdc.gov/phil/Details.aspx?pid=7827 Laurie Anne Walden, DVM Blacklegged tick (Ixodes pacificus). Image credit: CDC/James Gathany. Ticks in North Carolina are active all year round, but their activity increases dramatically in the spring and summer. Ticks spread bacteria and viruses (pathogens) that cause serious and sometimes fatal diseases in dogs, cats, and humans.
Ticks live mostly in tall grass, woodlands, undergrowth, groundcover plants, and secluded cracks and crevices. Some tick species infest houses. Ticks that are ready for a blood meal move to the tip of a grass blade or other vegetation and wait for a host animal to come along. They climb onto an animal when it brushes past (ticks don’t fly or jump). Ticks attach to an animal by clamping their mouthparts to the skin. Ticks spread pathogens when they take a blood meal. A tick has to be attached for some time before it can spread a pathogen. The amount of time depends on the tick species and the pathogen. North Carolina Ticks The geographic ranges of some tick species have expanded because of changing environmental conditions and the movement of host species like deer. Different tick species carry different pathogens, so tick-borne diseases that used to be more common in other parts of the country—like Lyme disease—are now common in North Carolina too. Identifying a tick’s species can help narrow down the pathogens the tick might be carrying. These are some of the tick species that live in North Carolina:
You don’t need to be able to tell tick species apart. But if you’re interested, here’s the link to NC State’s guide to ticks of North Carolina: https://eit-wagpress-prod.s3.amazonaws.com/media/documents/NC_Tick_Guide_v1.0_April_14_2023.pdf Tick-Borne Diseases of Dogs and Cats In dogs and cats, many tick-borne infectious diseases cause similar signs: loss of appetite, decreased energy, fever, and sometimes swollen lymph nodes and muscle or joint pain. Signs of illness appear days or weeks after a tick bite. These are some of the tick-associated diseases that affect dogs and cats in North Carolina. Ehrlichiosis and Anaplasmosis The bacteria that cause ehrlichiosis and anaplasmosis are spread by American dog ticks, blacklegged ticks, brown dog ticks, and lone star ticks. Ticks can transmit Ehrlichia bacteria within 3 to 6 hours after attachment. Lyme Disease Lyme disease is caused by infection with Borrelia burgdorferi bacteria. Blacklegged ticks transmit Borrelia 24 to 48 hours after taking a blood meal. Rocky Mountain Spotted Fever and Other Rickettsial Diseases American dog ticks, brown dog ticks, Gulf Coast ticks, and lone star ticks spread Rickettsia bacteria, which cause Rocky Mountain spotted fever and other diseases. Transmission is thought to happen 5 to 20 hours after tick attachment. Tick Paralysis Tick paralysis is caused by a reaction to a neurotoxin produced by American dog ticks, blacklegged ticks, and possibly other tick species. Affected animals have a stumbling gait that progresses to inability to move. Without treatment, this condition can be fatal. It’s treated by removing or killing all ticks on the animal. Prevention Limiting Exposure Keep your pets away from tall grass and underbrush. When walking or hiking, keep your dog on a leash and on the path. At home, remove groundcover plants from areas your pets can access and install a border of gravel or mulch between grass and woods. Wild animals are tick carriers, so remove vegetation and food sources that attract deer and other wildlife. Thoroughly check your pets for ticks after they’ve been in a tick area. Look through the entire coat, including inside the ears, between the toes and paw pads, under the front legs (armpits), between the back legs, and under the tail. Tick Preventive Products Effective tick preventives are available by prescription from your veterinarian and should be used all year round. Prescription products for dogs and cats are safe, but some products are better choices than others for an individual animal, so discuss the options with your veterinarian. Some products are oral (flavored chews) and others are topical (drops placed on the skin). Prescription tick preventives kill ticks soon after they attach, before they’ve had a chance to transmit pathogens. Animals taking these products are protected from many tick-borne diseases but can still carry live unattached ticks in their fur. These unattached ticks can drop off in the house or move to another animal (or you), so check your pets for ticks even if they are taking a prescription product. Repellents Talk to your veterinarian about safe tick repellents if you are seeing live unattached ticks in your pet’s fur and your pet is already taking a prescription product. Repellents are available without prescription, but some are safer and work better than others. Cats are very sensitive to pyrethrins and can have severe reactions to products labeled for dogs. Read product labels carefully. Never use a product meant to treat clothing or equipment on an animal, and never use a dog product on a cat. Removing Ticks If a tick is attached to your pet, remove it with tweezers, a tick removal tool, or your fingernails protected by disposable gloves. Grasp the tick’s head at the skin and gently pull it away from the skin until the entire head comes out. Clean the area with soap and water or rubbing alcohol. Avoid squashing the tick so you’re not exposed to whatever pathogens the tick is carrying. Kill the tick by placing it in a vial of rubbing alcohol or in a ziplock baggie with a cotton ball soaked in rubbing alcohol. Note the date of the tick bite in case your pet shows any signs of illness days or weeks later. If you want to be thorough, label your tick vial or baggie with the date and keep it for several weeks in case the tick is needed for identification and testing later on. Vaccination A Lyme disease vaccine is available for dogs. This vaccine is considered a lifestyle vaccine, so ask your veterinarian whether your dog should receive it. Sources
Image source: https://wwwn.cdc.gov/phil/Details.aspx?pid=7663 Laurie Anne Walden, DVM Photo by Alexa on Pixabay In the last few months, several animals in the Carolinas have tested positive for rabies, and a number of people and pets have been exposed to the virus. These are a few of the recent rabies cases and some statistics:
Rabies is a deadly viral disease that causes encephalitis, or brain inflammation. It is not curable but is very easy to prevent with the rabies vaccine. The virus is spread through saliva or nervous system tissue of infected animals. The virus is usually transmitted through a bite, scratch, or contact of infected saliva with broken skin or mucous membranes (eyes or mouth). Infected animals can transmit rabies before they show any signs of infection. This is one reason stray cats and feral cat colonies are a special risk for people. People are more likely to come in contact with stray cats than with wildlife. People who handle infected kittens and adult cats can be exposed to rabies without realizing the animal is carrying the virus. In North Carolina and South Carolina, rabies vaccination is mandated by law for all pet dogs, cats, and ferrets older than 4 months. An animal’s rabies vaccination status (current, overdue, or not documented) affects what happens to that animal if it’s exposed to rabies or bites someone, so don’t let your pets’ rabies vaccines expire. Local animal control officials decide whether an animal will be quarantined at home, quarantined at a facility, or euthanized for rabies testing, and that decision is based partly on rabies vaccination status. Take these steps to protect your pets and yourself from rabies:
Sources
Image source: https://pixabay.com/photos/raccoon-animal-mammal-nature-fur-3538081/ Laurie Anne Walden, DVM Image by Clinton Forry on Flickr, CC BY 2.0 license Photos of rabbits with horn-like growths popped up on the internet last month after people spotted the rabbits in northern Colorado. The growths are caused by infection with a papillomavirus, in the same family as the viruses that cause warts and cervical cancer in humans. The virus infecting these rabbits isn’t contagious to other species and usually causes wild rabbits less trouble than you would think.
Cottontail rabbit papillomavirus, also called Shope papillomavirus (for the person who first described it), is not a new virus. It’s been identified in museum specimens dating from the early 1900s. Infection is most common in cottontails and other wild rabbits in the midwestern United States. We could speculate that the long skin growths inspired the myth of the jackalope, the fabled jackrabbit with deer antlers on its head. In most wild rabbits, the growths are benign and eventually fall off on their own. Unless the growths interfere with eating and drinking, they don’t usually cause a problem. Infection in domestic rabbits is rare but potentially much more serious. In domestic rabbits, the growths are more likely to become malignant cancers than they are in wild rabbits. Cottontail rabbit papillomavirus is spread by flea, tick, and mosquito bites. The skin growths are in areas most often bitten by insects, which is why most are on the face and head. Because domestic rabbits are at risk of cancer, pet rabbits should be kept indoors in areas of the country where the virus is spreading, especially in the summer and fall when insects are most active. Rabbit papillomavirus infects only rabbits. Humans, dogs, cats, and other species are not at risk from this particular rabbit virus. Humans and other species have their own papillomaviruses, all of which are typically species specific (they aren’t contagious to other species). Human papillomavirus (HPV) is the name for hundreds of related viruses that cause various kinds of growths in people. Some of these growths, like common skin warts and plantar warts, are benign. Others, like genital, cervical, anal, and oral lesions, can become malignant cancers. HPV infection is a common sexually transmitted disease in humans. Scientists are very interested in finding out why some virus-related growths are benign but others turn into cancer, a process called malignant transformation. One of the best ways to study malignant transformation in humans is to study similar viruses that cause similar cancers in other animals. And it happens that cottontail rabbit papillomavirus was the first papillomavirus identified and the first shown to cause cancer in a mammal. This is why the virus is also named after Richard Shope, the cancer researcher who discovered it. So the next time you see a social media photo of a Frankenstein bunny, just think “Oh look, a valuable animal model of malignant transformation that helps us diagnose, prevent, and treat HPV and cancer in people.” Image source: https://www.flickr.com/photos/wd45/364229280, CC BY 2.0 Laurie Anne Walden, DVM US Department of Agriculture photo by Lance Cheung Cats are at risk of severe illness and death if they are infected with bird flu (highly pathogenic avian influenza A virus, type H5N1). The H5N1 influenza virus has been spreading worldwide for the past few years. An outbreak among poultry and dairy cattle in the United States has caused the deaths of millions of domestic poultry and led to recalls of raw meat–based pet diets and raw milk. Cats that have died from H5N1 infection in the United States have been infected by eating raw meat products or by drinking raw milk.
Avian influenza viruses start in migratory waterfowl like ducks and geese, who spread these viruses without getting sick themselves. Influenza viruses typically spread next to domestic poultry: chickens and turkeys. Mutations let influenza viruses jump to new species, including mammalian species like cows, pigs, cats, and humans. The H5N1 virus has spread to all of these species (1 person infected by contact with birds has died, but at this time transmission to humans is rare). Cats are at higher risk than dogs of becoming seriously ill if they are infected with H5N1 virus. All felines—domestic cats and big cats—are at risk. So far, H5N1 infections have been confirmed in indoor cats, barn cats, wild cats like bobcats and mountain lions, and captive big cats like tigers. How Cats Are Infected Cats are infected with H5N1 flu virus in these ways:
Raw Diets Carrying the Most Risk Raw diets containing poultry—chicken, turkey, or duck—are the biggest risk. Because H5N1 virus has also infected dairy cows, it’s possible (but less likely) for raw diets containing beef to be contaminated if these products contain meat from dairy cows. Frozen and freeze-dried poultry products are also a risk. Freezing and freeze drying are unlikely to kill influenza viruses because these methods are used to preserve viruses for research purposes, according to Dr Scott Weese, a zoonotic disease expert at the University of Guelph. High-pressure pasteurization (as opposed to high-heat cooking) is used for some commercial raw diets, but this method doesn’t always inactivate pathogens. High-pressure pasteurized diets have been recalled because of Salmonella contamination, and some could be contaminated with influenza virus. For more information about raw diets and the H5N1 virus, see Dr Weese’s article on the Worms and Germs website: https://www.wormsandgermsblog.com/2025/01/articles/animals/cats/h5n1-influenza-raw-diets-and-petsan-overview/ Signs of Infection in Cats Cats infected with H5N1 influenza virus show respiratory signs similar to flu in humans. They can also develop neurologic signs that mimic rabies and other nervous system disorders. These are some of the signs in cats:
Diagnosis and Treatment Highly pathogenic avian influenza is a reportable disease, so veterinarians collaborate with public health officials to test cats suspected of having H5N1 infection. The diagnostic tests chosen depend on the cat’s clinical signs. If the signs are compatible with rabies, the cat might have to be euthanized for rabies testing (always keep your pets’ rabies vaccinations up to date to reduce this risk). Treatment is mostly supportive care. Antiviral medications to treat H5N1 infection have not been tested in many cats yet. The prognosis for cats that are sick with H5N1 influenza is poor. How to Keep Cats and People Safe At this time, the H5N1 virus has not been shown to spread from cats to humans or from humans to other humans. Still, the American Veterinary Medical Association recommends taking these precautions:
If you think your cat might have H5N1 influenza, take these steps:
For More Information
Image source: https://www.flickr.com/photos/usdagov/49446130417/ Laurie Anne Walden, DVM Photo by Borna Bevanda on Unsplash Feline infectious peritonitis (FIP) is a viral disease that until recently was untreatable and almost always fatal in cats. An effective antiviral drug emerged a few years ago but was legally unavailable in the United States. Some cat owners bought the drug at high cost on the international black market, but this product was unregulated, untested, and possibly unsafe.
A compounded version of this antiviral drug, GS-441524, is now available in the United States by veterinary prescription. This means that FIP has become a treatable disease instead of a near-certain death warrant for cats. The US Food and Drug Administration (FDA) hasn’t officially approved the compounded product for use in cats. However, the FDA announced that because no approved drug is available, it won’t enforce drug approval requirements when a veterinarian prescribes this product for an individual cat.[1] Signs and Diagnosis of FIP The virus that causes FIP is a coronavirus. Feline coronavirus infection is very common in cats. The virus typically lives in the intestines without causing much trouble. In some cats, feline coronavirus mutates into a disease-causing strain that spreads through the body. This disease is FIP. The signs of FIP depend on whether a cat has the “wet” form (with fluid accumulation in the chest and abdomen) or the “dry” form (with inflammatory masses and other changes in the eyes, nervous system, kidneys, liver, or other organs). Some of the signs are swollen belly, decreased appetite, decreased energy, weight loss, fever, labored breathing, blindness, and seizures. Because the signs of FIP are nonspecific and because so many cats have been infected with feline coronavirus, diagnosis is not simple. The diagnosis is often presumptive, meaning that it’s not confirmed by definite tests but is suspected on the basis of clinical signs and the results of blood and urine tests, imaging studies, fluid analysis, and biopsy. Treatment GS-441524 is a metabolite of remdesivir. Remdesivir is used to treat COVID-19 in humans, but it’s not licensed for use in animals. Veterinarians can treat animals off label with drugs licensed for humans, so remdesivir is technically a treatment option for cats but it’s hard for veterinarians to access. Unlike remdesivir (an injectable product), compounded GS-441524 is a tuna-flavored tablet. It’s already being used to treat cats in Australia and the United Kingdom. The dose depends on the cat’s clinical signs, and the current recommendation is to continue treatment for 12 weeks. Reported survival rates for cats treated with GS-441524 range from 81% to 100%.[2] Without this treatment—or a similar antiviral drug if one becomes available—the prognosis is grim. References 1. FDA announces position on use of compounded GS-441524 to treat FIP. US Food and Drug Administration. May 10, 2024. Accessed September 3, 2024. https://www.fda.gov/animal-veterinary/cvm-updates/fda-announces-position-use-compounded-gs-441524-treat-fip 2. Tasker S, Addie DD, Egberink H, et al. Feline infectious peritonitis: European Advisory Board on Cat Diseases guidelines. Viruses. 2023;15(9):1847. doi:10.3390/v15091847 Image source: https://unsplash.com/photos/gray-tabby-kitten-leaning-on-white-wall-VwqecUsYKvs Laurie Anne Walden, DVM Toxoplasma gondii oocysts in fecal flotation solution. Image from CDC. Have you ever heard that pregnant people shouldn’t handle a cat’s litter box? This is because of the risk of toxoplasmosis. World Zoonoses Day, July 6, is a great time to talk about how this disease passes from animals to people and whether pregnant people really do get a 9-month pass on cleaning the litter box.
Zoonoses are diseases that are transmitted from nonhuman animals to humans. Toxoplasmosis is a zoonotic disease caused by infection with the protozoan parasite Toxoplasma gondii. Toxoplasmosis is one of the most common foodborne illnesses in people. The people who should be most cautious about T gondii infection are those with compromised immune systems and those who are pregnant. Toxoplasmosis in People People With Healthy Immune Systems People with healthy immune systems usually have no signs of T gondii infection and don’t know they’ve been infected. For those who develop signs, most have swollen lymph nodes or flu-like symptoms that get better on their own within a few weeks. Much less commonly, the infection can affect the eyes and cause vision loss. Whether or not the initial infection causes any signs of illness, the parasites remain in the body in a dormant state. The infected person develops immunity to T gondii. However, if the person’s immune system becomes compromised (because of chemotherapy, organ transplantation, or AIDS, for example), the T gondii organisms are reactivated and cause illness. People With Weakened Immune Systems In people with compromised immunity, toxoplasmosis affects the brain, eyes, lungs, and other organs. Either a new infection or a reactivated infection can cause seizures, confusion, and coordination problems. Fetuses Infected Before Birth A fetus won’t become infected if the mother was infected with T gondii before getting pregnant. In this case the mother already has immunity and won’t pass the infection to the unborn child (as long as she has a healthy immune system). If a mother is infected for the first time during or immediately before pregnancy, the fetus can be infected too because the mother doesn’t yet have immunity. Most people don’t know if they’ve been infected with T gondii in the past, so it’s safest for all pregnant people to take precautions to avoid infection. The consequences of infection in an unborn child can be severe. The pregnancy might end in miscarriage or stillbirth, or the fetus might develop anatomic abnormalities. More commonly, infected infants have no signs of infection when they’re born. These individuals can develop vision loss or neurologic problems years later. How People Are Infected
Toxoplasmosis in Cats Domestic cats and other felines are the only species that spread T gondii into the environment. Cats become infected after eating birds or rodents that have T gondii cysts in their bodies. Infected cats then shed T gondii oocysts (eggs) in the stool. The oocysts are not infective to other animals right away. After at least 1 day, the oocysts mature to a stage that can infect other animals. Infective oocysts can survive in the environment for years. Most infected cats don’t have any signs of illness. Cats with compromised immune systems can develop disease similar to that of humans with compromised immune systems. Identifying cats infected with T gondii is tricky. Cats shed oocysts in the stool for only a short time, so fecal tests aren’t reliable for diagnosing infection in cats. However, if a fecal test happens to show oocysts that look similar to T gondii, the cat’s owners should take precautions with the cat’s stool for a few weeks. A blood test showing that a cat has T gondii antibodies doesn’t tell us whether that cat is likely to start shedding oocysts that could put the family at risk. Precautions The CDC recommends these precautions to avoid toxoplasmosis:
Pregnant people should also take these precautions:
For More Information
Image source: https://www.cdc.gov/dpdx/toxoplasmosis/index.html Laurie Anne Walden, DVM Photo by Rafaëlla Waasdorp on Unsplash All dogs are at risk for leptospirosis and should be vaccinated for it every year, according to updated recommendations from the American College of Veterinary Internal Medicine (ACVIM).
Leptospirosis is caused by infection with Leptospira bacteria. The infection spreads from animals to humans, so leptospirosis is a public health hazard. Leptospirosis is a serious disease that damages the kidneys and other organs. The leptospirosis vaccine for dogs has previously been considered a lifestyle vaccine, given to dogs with certain risk factors but not necessarily to all dogs. Information about how the disease spreads has improved over the years, so the ACVIM now says that all dogs, regardless of their lifestyle and location, should receive the vaccine. Transmission Leptospira spread mainly through urine. Many wild and domestic animal species carry the bacteria and deposit them in the environment. Rats and other rodents are the most common carriers. Leptospira grow best in water and wet soil. Dogs with access to bodies of water, especially in warm climates, are at higher risk than others. However, the infection can also spread by direct contact (for example, when dogs hunt rodents) and in other ways, so outbreaks have happened among people and dogs living in urban areas and in drier and colder climates. Cats seem to be resistant to leptospirosis, and cases in cats are extremely rare. However, cats might be able to spread the bacteria to other animals. Disease Leptospirosis affects many organ systems. These are some of the most serious problems it causes:
These are some of the signs of infection:
Diagnosis and Treatment Leptospira can be hard to detect with laboratory tests. Definite diagnosis might require multiple blood and urine tests to isolate bacterial DNA and measure antibody titers. Dogs with suspected leptospirosis also receive baseline bloodwork, urinalysis, and chest radiographs. Leptospirosis is treated with antibiotics. Additional treatments depend on the individual patient’s course of illness and the organ systems affected. Some dogs with kidney injury caused by leptospirosis need dialysis. The risk of a person contracting leptospirosis directly from an infected dog is low because dogs don’t shed many Leptospira organisms in their urine. However, people caring for a dog with leptospirosis need to take precautions like avoiding contact with the urine, wearing protective clothing, and washing hands. Vaccination The doctors at Mallard Creek recommend that all dogs receive a leptospirosis vaccine starting at 9 weeks of age. Dogs need a booster vaccine 3 to 4 weeks later and then once a year. Leptospirosis vaccines are not all the same. Leptospira have many different variations, or serovars, and vaccines target only specific serovars. However, some don’t cover the serovars currently causing disease in dogs in the United States. Your veterinarian can advise you on the best vaccination plan for your own dog. Source Sykes JE, Francey T, Schuller S, Stoddard RA, Cowgill LD, Moore GE. Updated ACVIM consensus statement on leptospirosis in dogs. J Vet Intern Med. 2023;37(6):1966-1982. doi:10.1111/jvim.16903 Image source: https://unsplash.com/photos/a-dog-running-through-a-field-of-yellow-flowers-SEGsw2Kmd08 Laurie Anne Walden, DVM Photo by Sofia Shultz on Unsplash Cases of infectious respiratory disease in dogs have received media attention in the last couple of weeks. We don’t yet know what’s causing these illnesses or whether the reported cases are true outbreaks. However, there is no doubt that dogs can be exposed to a variety of infectious organisms, mostly affecting the respiratory and gastrointestinal (digestive) systems, when they’re around other dogs.
Take steps to reduce your dog’s risk if your dog goes to group settings like these:
Dogs in animal shelters are at especially high risk because incoming animals are likely to be carrying infections, overcrowding is common, and stress can blunt the immune response. Infectious disease agents—viruses, bacteria, parasites, and so forth—are spread in 5 main ways: by direct contact, through the air, by mouth, by vectors (mosquitoes, ticks, and other animals), and on objects (water bowls, shoes, etc). Dogs in group settings can be exposed through any of these routes. Infectious Respiratory Disease Canine infectious respiratory disease complex, also called kennel cough, is caused by a wide range of viruses and bacteria, like canine parainfluenza virus, canine influenza virus, and Bordetella bronchiseptica. These infectious agents are carried in respiratory secretions and transmitted by direct contact with an infected dog, through the air, or on contaminated objects. Symptoms include coughing, sneezing, and runny nose. Most dogs have mild illness and recover, but some develop pneumonia. Vaccines are available for some of the agents that cause respiratory disease. Infectious Gastrointestinal Disease Canine parvovirus is highly contagious among dogs. Infection is often fatal but can be prevented with vaccination. A number of other viruses, bacteria, and protozoa that cause gastrointestinal disease are contagious among dogs. These agents are shed in feces, so transmission is generally by direct contact, by mouth, or on contaminated objects. Symptoms are related to the digestive tract: vomiting, diarrhea, loss of appetite, and so forth. Raw meat is a source of bacterial infection (E coli, Salmonella, Campylobacter, Listeria, etc). Dogs that eat raw meat can shed these bacteria in their feces without showing any symptoms, and other dogs that have contact with the feces can become infected. Parasites Intestinal parasites—most often hookworms and roundworms—are common in dogs that aren’t receiving regular parasite prevention medication. These worms are contagious to other dogs (and people) through feces. External parasites like fleas and ticks are vectors that spread infectious diseases to dogs and people. Some of these diseases, like bartonellosis, Rocky Mountain spotted fever, and Lyme disease, can be quite serious. Dogs can also catch fleas and mange mites directly from other dogs. How to Reduce Your Dog’s Risk
Image source: https://unsplash.com/photos/black-and-tan-german-shepherd-and-brown-and-black-german-shepherd-mix-dogs-on-brown-field-Z-lEcNOfWMI Laurie Anne Walden, DVM Photo by Bogdan Farca on Unsplash Cat scratch disease in humans is caused by infection with Bartonella henselae bacteria, which are transmitted by cat fleas. This potentially serious infection is an important reason to use flea control products for all cats all year round.
Transmission Bartonella species are spread by arthropods such as fleas, lice, and sand flies. People can be infected by several species of Bartonella. In the United States, B henselae is the most common cause of disease in humans. Cat fleas shed B henselae in their feces. Cats that harbor fleas carry these bacteria on their claws, on their skin, and in their mouths. Humans are usually infected by cat scratches contaminated with flea feces. People can also be infected by being bitten or having an open wound licked by a cat carrying B henselae. Dogs can also carry B henselae, but they typically have a lower bacterial load than cats. Whether dogs can transmit the infection to humans is not known. Infection in Humans In humans, B henselae infection can cause fever and swollen lymph nodes. More rarely, it causes inflammation of the heart valves, brain, bone, joints, eyes, or other organs. People with compromised immunity, such as those with HIV infection, are more likely than others to develop serious illness from B henselae infection. Infection in Cats Cats very commonly carry B henselae. Up to 40% of shelter cats in some geographic locations have B henselae in their bloodstream. Kittens tend to carry more bacteria than adult cats. Cats carrying B henselae usually have no symptoms. Because these bacteria are well adapted to living in cats’ bodies, they very rarely make cats sick. However, some cats develop fever, vomiting, eye inflammation, or swollen lymph nodes. Bartonella infection can be difficult to diagnose in cats. No antibiotic has been shown to completely eliminate the bacteria from carrier cats, and prolonged antibiotic treatment can cause the bacteria to develop antibiotic resistance. For these reasons, testing and treatment are recommended only for cats that have signs of illness caused by Bartonella infection. Prevention Because flea control prevents B henselae transmission among cats, the American Association of Feline Practitioners recommends that all cats receive flea prevention products year round. The CDC recommends these steps to prevent B henselae infection in people:
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