Can Your Cat Give You a Dangerous Infection?


Mycoplasma are a type of bacteria that lack cell walls. They are among the smallest self-replicating organisms and can cause infections in humans and animals. Mycoplasma infections are common in cats. While some types of mycoplasma only infect other cats, there are strains that can be transmitted from cats to humans.

This article will examine the different types of mycoplasma found in cats, transmission between cats, the strains that can spread to humans, how infection occurs, symptoms, testing, treatment and prevention.

What is Mycoplasma?

Mycoplasmas are a type of bacteria that lack a cell wall. This makes them the smallest free-living organisms. Mycoplasmas are widespread in nature and found in animals, humans, insects, and plants (1).

These tiny bacteria can live on the surface of cells or invade the cells of their hosts. Many mycoplasma species are commensal organisms that colonize mucosal surfaces, such as the respiratory or urogenital tracts, without causing disease. However, some mycoplasmas are pathogenic and can cause chronic infections in susceptible hosts (2).

Common mycoplasma infections seen in humans include walking pneumonia (Mycoplasma pneumoniae) and urethritis/pelvic inflammatory disease (Mycoplasma genitalium). Mycoplasmas are also implicated in diseases like rheumatoid arthritis and Crohn’s disease. Due to their lack of a cell wall, mycoplasmas are naturally resistant to certain antibiotics like penicillin (1).

Mycoplasma in Cats

There are several species of mycoplasma that can infect cats. The most common feline mycoplasma species include:

  • Mycoplasma felis – Considered the most pathogenic mycoplasma species in cats. It is associated with respiratory infections and can cause severe disease, especially in younger cats.

  • Mycoplasma gateae – Another respiratory pathogen in cats, though less severe than M. felis. It is a common coinfection with other respiratory viruses.

  • Mycoplasma arginini – Found in the upper respiratory tract of healthy cats. May act as an opportunistic pathogen in immunocompromised cats.

  • Mycoplasma cynos – Usually associated with respiratory disease in dogs, but has been isolated from cats as well.

These mycoplasma species are difficult to distinguish clinically. Testing is required to differentiate between them. Polymerase chain reaction (PCR) assays are commonly used for detection. Serology can also help determine prior exposure and immune status.

Mycoplasmas frequently complicate viral upper respiratory infections (URIs) in cats. They can cause more severe clinical signs and be harder to treat. Biofilms formed by mycoplasmas may contribute to chronic carrier states and recurrent infections.

Transmission Between Cats

Mycoplasma spreads easily between cats through direct contact and exchange of respiratory secretions. When an infected cat sneezes, coughs, or even vocalizes, it releases respiratory droplets containing the mycoplasma organisms into the air. These droplets can then be inhaled or ingested by another cat, resulting in a new infection.

Grooming behaviors like mutual licking can also facilitate transmission. Saliva contains the mycoplasma bacteria, so when cats groom each other they expose their respiratory tracts. Sharing food bowls or other objects can also spread contaminated saliva between cats.

Mycoplasma is very contagious within multi-cat households or shelters. Frequent face-to-face interactions allow the mycoplasma pathogens to readily pass from cat to cat. The high population density in these settings enables rapid transmission through the group.

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Mycoplasma that can be Passed to Humans

Of the different types of mycoplasma found in cats, only a few have been shown to be able to infect humans:

  • Mycoplasma felis – This is the most common mycoplasma species found in cats that can also infect humans. According to one study, M. felis was detected in 15% of humans with mycoplasma infections who had contact with cats (
  • Mycoplasma gateae – This species has been found to rarely infect immunocompromised humans, especially in cases involving close contact with infected cats (
  • Mycoplasma haemominutum – There are a few documented cases of this feline mycoplasma infecting humans with compromised immune systems (

Overall, while mycoplasma transmission from cats to healthy humans is very rare, immunocompromised individuals are at a higher risk of infection from some feline mycoplasma species with close cat contact.

Transmission from Cats to Humans

Mycoplasma bacteria can be transmitted from cats to humans through close contact with infected cats. The main routes of transmission are through saliva and respiratory droplets from coughing or sneezing. When an infected cat licks a person or rubs against them, the bacteria can be transferred through the saliva onto the skin. Mycoplasma can also be spread through airborne droplets if a person inhales respiratory secretions from an infected cat [1].

Sharing food and water bowls with an infected cat can also spread mycoplasma to humans. Similarly, handling toys, bedding or litter from an infected cat could lead to transmission if the person then touches their mouth, nose or eyes before washing their hands. Bites and scratches from infected cats present another opportunity for bacteria transmission through the saliva [2].

Overall, close interactions with infected cats allow mycoplasma bacteria to spread through saliva and respiratory secretions onto human skin or mucous membranes, resulting in potential human infection.

Symptoms in Humans

When humans are infected with mycoplasma from cats, the most common symptoms include:

  • Fever, chills, and body aches – Mycoplasma infections often cause flu-like symptoms like fever, chills, and body aches. Fevers are typically mild.
  • Cough – A dry, hacking cough is very common with mycoplasma pneumonia. The cough may persist for weeks or months.
  • Fatigue and weakness – Feeling very tired and fatigued is common, as the infection can sap energy levels.
  • Headaches – Throbbing headaches are commonly reported with mycoplasma infections.
  • Sore throat – A sore, scratchy throat can occur when mycoplasma infects the throat and respiratory tract.
  • Shortness of breath – Difficulty breathing can occur when mycoplasma causes pneumonia and inflammation in the lungs.

Some people may only experience mild cold-like symptoms, while others can become quite ill with pneumonia. The elderly, people with weakened immune systems, and those with chronic lung diseases are at highest risk for severe pneumonia.

Symptoms typically begin 1-4 weeks after exposure to an infected cat. Mycoplasma pneumonia symptoms can persist for months without treatment.

Testing and Diagnosis

Mycoplasma infection in humans is typically diagnosed based on a combination of symptoms, chest X-ray findings, and laboratory tests. According to the CDC, clinical labs can use culture, serology, or molecular methods to detect Mycoplasma pneumoniae infections.

A chest X-ray often shows characteristic signs of mycoplasma pneumonia such as infiltrates in a lacy pattern. However, the chest X-ray appearance can mimic other types of bacterial or viral pneumonia.

Blood tests look for antibodies to Mycoplasma pneumoniae. A four-fold rise in IgG antibodies between acute and convalescent serum samples provides evidence of recent infection. PCR tests that detect Mycoplasma DNA in respiratory secretions are also available. PCR is typically more sensitive than culture.

Because the symptoms of mycoplasma pneumonia are non-specific, laboratory testing is important to confirm the diagnosis and rule out other potential causes. Prompt and accurate diagnosis allows for appropriate treatment with antibiotics.


There are several antibiotic treatment options for humans infected with mycoplasma species that can be transmitted from cats. According to the CDC, doctors often prescribe macrolide antibiotics like azithromycin, clarithromycin, or erythromycin to treat Mycoplasma pneumoniae pneumonia in humans. These antibiotics help stop the growth of mycoplasma bacteria and allow the immune system to clear the infection. Treatment is usually for 7-14 days.

Some other antibiotics that may be used to treat mycoplasma infections from cats include tetracyclines like doxycycline, fluoroquinolones like levofloxacin, and aminoglycosides like gentamicin. The specific antibiotic prescribed will depend on the type of mycoplasma species, the site of infection, and the severity of symptoms. Doctors may also prescribe cough medicine to help manage coughing from mycoplasma respiratory infections.

In most healthy people, mycoplasma infections are mild and clear up within a few weeks with antibiotic treatment. However, the infection may last longer or be more severe in people with weaker immune systems. Completing the full antibiotic course is important to clear the infection entirely and prevent recurrence of symptoms.


There are several steps cat owners can take to prevent the spread of mycoplasma infections between cats and humans:

  • Practice good hygiene like washing hands before and after handling cats, cleaning litter boxes, or touching contaminated surfaces. Wear gloves when cleaning litter boxes.
  • Have new cats tested for mycoplasma infections before introducing them to other cats in the household. Isolate infected cats until treatment is complete.
  • Keep cats indoors and do not allow them to roam free, hunt, or interact with strays to prevent exposure.
  • Have cats regularly tested and treated for mycoplasma infections. Work with your vet to determine an appropriate testing schedule.
  • Clean and disinfect cat feeding dishes, bedding, litter boxes, and toys regularly.
  • Avoid touching your face after handling cats until you have washed your hands. Do not let cats lick your face.
  • Pregnant women should take extra precautions like wearing masks and gloves when cleaning litter boxes.
  • Talk to your vet about vaccination options to help prevent certain mycoplasma strains in cats.

By following these tips, cat owners can significantly reduce the risks of transmitting mycoplasma infections between cats and humans.

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