How Susceptible Are Pets to Mycoplasma Infections
With recent increases in Mycoplasma pneumonia cases among children, mycoplasma infections have attracted significant public concern. Mycoplasma affects dogs and cats as well as humans, though the species of mycoplasma differ between them. Let’s take a look at mycoplasma in dogs and cats.
l Mycoplasma as an Opportunistic Pathogen: Causing Disease in Combination with Other Bacteria or Viruses
Mycoplasma is a type of Gram-negative bacteria that lacks a cell wall and is widely distributed in the environment. It is the smallest known prokaryote and can form colonies on agar that have a characteristic “fried-egg” appearance. Depending on their ability to infect red blood cells, mycoplasmas are classified as hemotropic or non-hemotropic [1]. Non-hemotropic mycoplasmas commonly inhabit the upper respiratory tracts of healthy dogs and cats as part of their natural flora [2]. Mycoplasma is an opportunistic pathogen. When present alone, it typically induces mild or subclinical symptoms; however, co-infection with other bacteria or viruses can result in significant pathology.
|
Mollicutes |
Mycoplasmatales [Requires Sterols for Growth?] |
Mycoplasmataceae |
Bartonella |
Bartonella henselae |
Hemotropic mycoplasmas |
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Bartonella vinsonii |
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Bartonella elizabethae |
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Haemobartonella |
Haemobartonella suis |
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Haemobartonella ovis |
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ect… |
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Mycoplasma |
Mycoplasma gallisepticum |
Non-hemotropic mycoplasmas |
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Mycoplasma bovis |
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Mycoplasma mycoides |
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Mycoplasma cynos |
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Mycoplasma pneumoniae |
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Mycoplasma hyosynoviae |
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Mycoplasma hyopneumoniae |
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Mycoplasma felis |
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ect… |
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Ureaplasma |
Ureaplasma urealyticum |
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ect… |
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Acholeplasmataceae |
Acholeplasma |
Acholeplasma laidlawii |
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Acholeplasma granularum |
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Acholeplasma notomytis |
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Acholeplasma modicum |
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Acholeplasma oculi |
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Spiroplasmataceae
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Figure 1. Classification of Canine, Feline and Other Mycoplasma Species (Referenced from "Bergey’s Manual of Systematic Bacteriology," 9th Edition)
l Mycoplasma felis and Mycoplasma cynos may be significantly associated with respiratory diseases.
Dozens of Mycoplasma species can infect dogs and cats, found in various sites such as the upper respiratory tract, lower respiratory tract, joints, urine, and reproductive tract (see Table 1).
Table 1. Mycoplasma Species Isolated from Dogs and Cats ("Infectious Diseases of Dogs and Cats," 4th Edition)
Research has confirmed that Mycoplasma felis is a pathogenic agent associated with conjunctivitis in kittens [3]. In a study involving cats with ocular diseases at two commercial laboratories in Canada, the PCR identification rates of mycoplasma from corneal or conjunctival swabs were 11% and 27%, respectively, which were higher than those for feline herpesvirus type 1 (4% and 21%) and Chlamydia felis (2% and 17%). The prevalence of Mycoplasma felis in conjunctival swabs from cats with conjunctivitis was found to be 9.6% and 25% through PCR or culture testing, compared to 2.3% and 0% in clinically healthy cats, respectively [4,5]. Additionally, Mycoplasma felis has also been isolated from cats suffering from interstitial ulcerative keratitis or keratitis, or both [9].
There are numerous Mycoplasma species that can infect dogs, with certain strains also present in healthy dogs (see Table 1). It is currently believed that mycoplasma infections in dogs, such as Mycoplasma cynos, exhibit both commensal and pathogenic behavior in dogs, with its role in respiratory infections varying depending on the sampling location. The pathogenicity of M. cynos is commonly observed in the lower respiratory tract [6]. A study conducted in New Zealand in 2018 indicated that the likelihood of M. cynos infection was higher in diseased dogs (17%, 8/47) compared to healthy dogs (4%, 2/47). Furthermore, when M. cynos co-infects with other pathogens, such as CRCoV or M. canis, the symptoms are often more severe [7].
l Criteria for Selecting Mycoplasma Species in the Respiratory Testing of Dogs and Cats by GlinX
Based on the research findings mentioned above, GlinX has chosen Mycoplasma felis due to its established pathogenicity in feline respiratory diseases. Comparison studies show that the primers used for Mycoplasma detection by GlinX specifically amplify M. felis and do not match the sequences of other common upper respiratory mycoplasmas (see Figure 2).
Figure 2. GlinX Mycoplasma Primers Specifically Amplify Mycoplasma felis
Clinical samples were tested for mycoplasma using GlinX primers, Brand A primers, and literature-based primers for PCR analysis. For samples containing non-Mycoplasma felis strains, no amplification was observed with the GlinX PCR test (see Table 2).
|
Clinical samples |
GlinX mycoplasma |
Brand A mycoplasma |
Literature-based mycoplasma |
|
1 |
N😯Ct |
29.9 |
26.32 |
|
2 |
N😯Ct |
30.65 |
25.17 |
|
3 |
N😯Ct |
30.79 |
24.23 |
|
4 |
N😯Ct |
34.47 |
31.77 |
Table 2. PCR Results for Mycoplasma Using GlinX, Brand A, and Literature-Based Primers
Cases where clinical symptoms do not align with feline respiratory mycoplasma test results may be attributed to inconsistencies in the detection range or the involvement of other pathogens causing the disease.
For canine respiratory pathogens, specific sampling locations are important due to the distinct pathogenic nature of certain mycoplasma species. M. cynos, for example, is often found in mixed infections with other mycoplasmas like M. canis. Therefore, the detection range for canine mycoplasma has been broadened to align with current research while providing practical clinical insights. Currently, GlinX can detect major mycoplasma species in dogs, including M. cynos, M. canis, M. edwardii, and M. bovis, along with the capability to match various other mycoplasmas.
l GlinX data shows that Mycoplasma felis infections are more common in autumn and winter seasons, while canine mycoplasma infections are more frequent during the transition between winter and spring. Both types of infections have a high co-infection rate with other respiratory pathogens.
Based on data from the GlinX automated nucleic acid system, we conducted a statistical analysis of over 250,000 cases from September 2022 to the present. Nationwide, the overall positivity rate for Mycoplasma felis in the feline respiratory five-in-one panel was 31.97%. The trend chart (see Figure 3) indicates that the positivity rate remained relatively stable, with higher detection rates from September 2022 to February 2023, a slight decline afterward, and a resurgence in June 2023. Overall, Mycoplasma felis infections were more prevalent in the fall and winter. The rate of single Mycoplasma felis infections was 9.65%, while mixed infections with other pathogens were 22.32%, showing that mixed infections were more common. Single infections exhibited notable fluctuations, declining from September to December 2022, gradually rising to a peak in August 2023, and then gradually decreasing through November 2023 (see Figure 4). This pattern indicates that single Mycoplasma felis infections are more common in autumn. Regionally (see Table 3), the highest positivity rate for Mycoplasma felis was observed in the Southwest China (34.28%), followed by the Northeast China (32.61%), South China (32.37%), Central China (32.00%), East China (31.41%), Northwest China (30.48%), and North China (29.13%).
Figure 3. Trend Chart of the Total Positivity Rate for Mycoplasma felis in Feline Five-In-One Respiratory PCR Panel
Figure 4. Trend Chart of the Single Infection Rate for Mycoplasma felis in Feline Five-In-One Respiratory PCR Panel
|
Regions |
Number of Positive Detections for Mycoplasma felis |
Total Number of Feline Five-In-One Respiratory PCR Panel tests |
Positivity Rate |
|
Northwest |
2765 |
9071 |
30.48% |
|
Southwest |
6091 |
17770 |
34.28% |
|
North |
8756 |
30059 |
29.13% |
|
Central |
5070 |
15844 |
32.00% |
|
East |
27923 |
88900 |
31.41% |
|
South |
8682 |
26821 |
32.37% |
|
Northeast |
3620 |
11102 |
32.61% |
Table 3. Regional Positivity Rate of Mycoplasma felis in the Feline Five-in-One Respiratory PCR Panel
We also analyzed the results of the canine six-in-one Respiratory PCR Panel from September 2022 to the present, with nearly 10,000 cases. The data shows a total positivity rate of 74.67% for canine mycoplasma. The trend chart (see Figure 5) indicates that the overall positivity rate remained relatively stable, with the lowest detection rates occurring from late November to December in both 2022 and 2023. The detection rate was relatively higher from January to March 2023. The rate of single mycoplasma infections was 28.64%, while the co-infection rate with other pathogens was 46.03%, indicating that mixed infections are more common in clinical practice.
A distinct peak in single canine mycoplasma infections was observed in January 2023, gradually increasing from November 2022, reaching its peak, and then declining until April 2023. After that, the detection rates remained relatively stable, with minor fluctuations (see Figure 6). Overall, canine mycoplasma infections are more frequent during the winter-spring transition. Regional data (see Table 4) indicates that the highest positivity rate for canine mycoplasma was in South China (76.57%), followed by Southwest China (76.51%), Northwest China (76.00%), Central China (75.29%), North China (75.07%), Northeast China (74.97%), and East China (72.62%).
Figure 5. Trend of Total Positivity Rate for Canine Mycoplasma in the Canine Six-in-One Respiratory PCR Panel
Figure 6. Trend of Single Infection Rate for Canine Mycoplasma in the Canine Six-in-One Respiratory PCR Panel
|
Regions |
Number of Positive Detections for Canine Mycoplasma |
Total Number of Canine Six-in-One Respiratory PCR Panel Tests |
Positivity Rate |
|
Northwest |
266 |
350 |
76.00% |
|
Southwest |
632 |
826 |
76.51% |
|
North |
1659 |
2210 |
75.07% |
|
Central |
710 |
943 |
75.29% |
|
East |
2172 |
2991 |
72.62% |
|
South |
451 |
589 |
76.57% |
|
Northeast |
716 |
955 |
74.97% |
Table 4. Regional Positivity Rate of Canine Mycoplasma in the Canine Six-in-One Respiratory PCR Panel
Treatment of Mycoplasma Infections:
Antimicrobial Treatment:
Due to the challenging cultivation requirements of mycoplasma, antibiotic sensitivity testing is rarely performed. Mycoplasma species are generally sensitive to tetracyclines (such as doxycycline), fluoroquinolones (such as marbofloxacin, pradofloxacin), macrolides (such as azithromycin, roxithromycin), aminoglycosides, lincosamides, and chloramphenicol. The most commonly used antibiotics in clinical practice are the first three classes (see Table 3). Clinical symptoms often subside within 7 days, but chronic intracellular infections may be difficult to completely eradicate. Some cats may still test PCR-positive even after 28 days of treatment, so it is recommended to continue treatment for at least 42 days. During the treatment period, it is important to follow the veterinarian’s instructions for proper antibiotic use and to complete the full course of treatment to ensure effective control of the infection.
Table 5. Oral Antimicrobial Therapy for Respiratory Mycoplasma Infections in Cats (from "August’s Consultations in Feline Internal Medicine, Volume 7" )
Supportive Treatment:
Symptomatic treatments can be implemented to alleviate discomfort in cats. For example, conjunctivitis can be treated with topical eye medications, while nasal flush can help clean the nasal passages. Bronchodilators may be beneficial for cats exhibiting coughing or lower respiratory symptoms. These interventions should be tailored to the cat's specific condition and implemented under the guidance of a veterinarian.
Immunity Support:
Providing proper nutrition, maintaining a healthy environment, and minimizing stress are key to enhancing a cat's immune system, enhancing its ability to fight off pathogens..
In conclusion, the treatment plan for mycoplasma infection should be tailored to the specific condition of the cat. It is recommended to consult a professional veterinarian to get advice and guidance based on the cat's clinical signs and overall health status.
Summary:
In summary, mycoplasma is a common pathogen in canine and feline respiratory infections, often co-infecting with other respiratory pathogens. Mycoplasma infections remain prevalent throughout the year. However, Mycoplasma felis infections are more common in autumn and winter, while canine mycoplasma infections are more frequent during the transition from winter to spring. Mycoplasma screening is important especially during peak infection seasons. Nationwide, mycoplasma detection rates are higher in certain regions, but no clear regional trends have been identified.
GlinX's canine and feline respiratory PCR panels provide accurate diagnostic services, ensuring the health and well-being of your pets.
References:
[1] Fulvio Marsilio, et al. Feline respiratory Mycoplasma infections [EB/OL]. (2020-5)[2021-11]. http://www.abcdcatsvets.org/feline-respiratory-mycoplasma-infections.
[2] AROCH I, OFRI R, SUTTON G A. Ocular Manifestations of Systemic Diseases [J]. Slatter's Fundamentals of Veterinary Ophthalmology, 2008, 374-418.
[3] Tan R: Suceptibility of kittens to Mycoplasma felis infection. Jpn J Exp Med 44:235-240, 1974.
[4] Haesebrouck F, DeVriese LA, van Rijssen B, et al. 1991. Incidence and significance of isolation of Mycoplasma felis from conjunctival swabs of cats. Vet Microbiol 26:95-101.
[5] Lein DH. 1989. Mycoplasma infertility in the dog: diagnosis and treatment. Proc Soc Theriogenol 9:307-313.
[6] A systematic review and meta‐analyses of the association between 4 mycoplasma species and lower respiratory tract disease in dogs.2018
[7]A survey of canine respiratory pathogens in New Zealand dogs.2018
[8] Infectious Diseases of Dogs and Cats, 4th Edition
[9] Infectious Diseases of Dogs and Cats, 7th Edition
[10] August’s Consultations in Feline Internal Medicine, Volume 7
[11] Bergey’s Manual of Systematic Bacteriology, 9th Edition
