Introduction
Cats are one of the most popular pets globally, with an estimated 90 million domesticated cats living in homes in the United States alone. Traditionally, many cat owners allowed their feline companions to freely roam outdoors. However, in recent decades there has been a dramatic shift towards keeping cats exclusively indoors.
Indoor cats are felines that live entirely within their owner’s home and do not have access to the outdoors. In contrast, outdoor cats are allowed to roam freely outside and access the outdoors whenever they please through a cat door or other means. According to the American Veterinary Medical Association (AVMA), over the past 30 years the percentage of US cat owners keeping their pets strictly indoors has risen from around 35% in the 1980s to over 60% today (Foreman-Worsley et al., 2021).
This increase in indoor cat ownership has sparked debates around whether keeping cats confined indoors poses any risks in terms of disease. Do indoor cats carry more diseases than outdoor cats? This article will examine that question in detail.
Common Diseases in Cats
Some of the most common diseases seen in cats include:
- Feline Immunodeficiency Virus (FIV) – FIV is a retrovirus that weakens a cat’s immune system and makes them more susceptible to other diseases. It is spread through bite wounds from infected cats and has no cure, but can be managed with supportive care. [1]
- Feline Leukemia Virus (FeLV) – FeLV suppresses the cat’s immune system and can lead to anemia, leukemia, and other cancers. It is transmitted through saliva, urine, feces, and milk of infected cats. There is no cure but vaccines can help prevent infection. [2]
- Feline Panleukopenia Virus – Also called feline distemper, this virus attacks the gastrointestinal tract, immune system, and nervous system. It spreads through contact with infected feces and has no specific treatment, but supportive care can help. Vaccination prevents infection.
- Ringworm – Caused by a fungus, ringworm leads to circular patches of hair loss and scales on the skin. It spreads through contact with spores and is treated with antifungal medication and lime sulfur dips.
Outdoor Risk Factors
Outdoor cats are more likely to be exposed to infectious diseases for several reasons:
Unneutered male cats frequently get into fights with other cats over territory and females, leading to the spread of diseases through bites and scratches. Diseases like feline leukemia virus, feline immunodeficiency virus, and abscesses are more common in roaming tomcats.
Outdoor cats encounter other cats as they roam, including feral cats and strays carrying diseases. Diseases like feline panleukopenia virus, rabies, ringworm, and fleas can spread through contact with infected cats.
Outdoor cats hunt and eat wild animals like rodents and birds. These prey animals can transmit diseases like Bartonella henselae (cat scratch fever) and toxoplasmosis to cats who eat them.
Indoor Risk Factors
Even though indoor cats are isolated from many of the outdoor hazards, there are still several risk factors for disease transmission within the home. Some of the main risks include:
Litter boxes – According to the Cornell Feline Health Center, litter boxes can harbor infectious organisms and parasites like Toxoplasma gondii, the parasite that causes toxoplasmosis (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/zoonotic-disease-what-can-i-catch-my-cat). Maintaining clean litter boxes and changing litter frequently can help reduce risk.
Multi-cat households – Having multiple cats increases the risk of spreading diseases between cats, especially for upper respiratory infections. Maintaining vaccinations and isolating any sick cats can help control outbreaks.
New cats introduced – Bringing a new cat into the home introduces new risks of bringing in a disease, especially if the cat has an unknown background or history. Keeping new cats quarantined and screened for infectious diseases can reduce transmission to existing cats.
Mitigating Disease Risk
There are several steps cat owners can take to help mitigate the risk of diseases in indoor cats:
Spay/Neuter – Spaying or neutering cats helps prevent the spread of certain diseases like feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) that are passed through bodily fluids.1
Keep Up with Vaccines – Vaccinating cats according to vet recommendations creates immunity against dangerous illnesses like rabies, feline distemper, and more. Core vaccines should be boosted yearly.2
Clean Litter Frequently – Scooping litter boxes daily and changing litter regularly helps prevent the spread of toxoplasmosis and parasites through infected feces.3
Annual Vet Visits – Regular veterinary checkups allow early detection and treatment of medical issues before they become serious illnesses.
Signs of Illness
There are several signs that may indicate your indoor cat is unwell. These include changes in behavior, poor coat condition, changes in litter habits, sneezing, and coughing.
Changes in behavior like decreased activity, irritability, or hiding more than usual could signal illness. Lethargy and disinterest in playtime or food are also concerning behavioral shifts according to VCA Hospitals (https://vcahospitals.com/know-your-pet/recognizing-signs-of-illness-in-cats).
A poor, unkempt coat or excessive shedding may indicate illness. Cats are fastidious groomers, so lack of grooming habits could mean something is wrong. Weight loss or gain, hair loss, and dandruff are other coat signs per Hillcrest Animals (https://www.hillcrestanimals.com/site/blog-memphis-vet/2020/03/12/how-to-tell-if-your-cat-is-sick).
Inappropriate urination or defecation outside the litter box, straining to urinate, and changes in urine or stool frequency/appearance can also indicate illness. Cats are extremely clean about litter habits.
Sneezing, coughing, wheezing, and nasal discharge are respiratory signs warranting veterinary examination.
Diagnostic Testing
To determine if an indoor cat has contracted any concerning diseases, vets may run several diagnostic tests. Two common viral disease tests check for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) [1]. These tests look for the presence of viral proteins in a blood sample using either ELISA or PCR tests. At-home test kits are available, but veterinary lab tests are considered more accurate. FeLV and FIV are spread through biting and cannot be transmitted to humans.
A fecal examination checks for intestinal parasites like roundworms, hookworms, and protozoa [2]. Droppings are inspected under a microscope for parasite eggs and cysts. A fecal flotation test uses a solution to help separate parasite eggs from stool for easier identification.
A urinalysis can screen for conditions like urinary tract infections, diabetes, and kidney disease. The urine sample is tested for chemical properties and examined under a microscope for crystals, cells, or bacteria.
Treatment Options
There are several options for treating diseases in cats:
Supportive care is often an important part of treatment. This may include providing fluids, nutrition and electrolyte replacement therapy. Keeping the cat comfortable, clean and monitoring vitals are also key parts of supportive care.
Antibiotics or antivirals may be prescribed depending on the disease. Antibiotics can treat secondary infections associated with viruses. Antivirals may be used for diseases like feline immunodeficiency virus (FIV). According to Cornell University College of Veterinary Medicine, antivirals like AZT can help cats with conditions like stomatitis associated with FIV.
Anti-inflammatory medications are often used to reduce pain, fever and inflammation associated with diseases. Corticosteroids like prednisone may be prescribed but other NSAIDs can also be used under veterinary guidance.
Prognosis
Overall, the prognosis for indoor cats with common diseases is quite good with proper veterinary care and owner diligence, as risks from infectious diseases can be considerably reduced when cats are kept indoors.
However, some concerning diseases like feline infectious peritonitis (FIP) remain difficult to cure and untreatable in many cases. FIP is caused by feline coronavirus infection and results in severe systemic inflammatory disease. According to the UC Davis School of Veterinary Medicine, there is no effective antiviral treatment for FIP infection, and the prognosis is poor once clinical signs develop.
With routine veterinary care including exams, bloodwork, vaccines, parasite prevention, and prompt treatment when ill, indoor cats can live long, relatively healthy lives. But fatal diseases like FIP remain a tragic threat. Responsible cat ownership with an understanding of disease risks is essential, even for strictly indoor cats.
Conclusion
In summary, there are risks to both indoor and outdoor lifestyles for cats. Outdoor cats face many dangers such as cars, other animals, parasites, and infectious diseases. However, indoor cats are not risk-free and can develop issues like obesity, dental disease, and stress if care is not taken to enrich their environment and routine. The average lifespan of an indoor cat is much longer at 13-17 years vs just 2-5 years for outdoor cats. While no environment is perfect, proactive care from an owner can greatly reduce health risks for an indoor cat. This includes providing exercise, mental stimulation, veterinary care, proper nutrition, and a clean litterbox. With diligence and attentive caretaking, it’s very possible for an indoor cat to live a long and fulfilling life.