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Anaplasmosis (Parasitic Infection Caused by Anaplasma Species) in cats

Occurrence: rarer
Location of illness: General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

If the condition worsens / symptoms persist, consult a veterinarian.

An interesting overview of gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. problems in cats, supplemented by information on the intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. microbiome and the importance of probiotics, can be found here: https://petsvetcheck.de/fachbeitrag/magen-darm-probleme-bei-katzen/

Definition

Anaplasmosis in cats is an infection caused by bacterial parasites of the genus Anaplasma, which is primarily transmitted by ticks. This infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. can lead to a variety of clinical symptoms, ranging from mild to severe.

The most important facts at a glance

Anaplasmosis in cats is caused by bacteria of the genus Anaplasma, specifically Anaplasma phagocytophilum. These bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. live in the white blood cells and are mainly transmitted by ticks, especially Ixodes ticks. Cats can be infected through the bite of an infected tick. Common symptoms include loss of appetite, Fever, enlarged lymph nodes, and general weakness. In more severe cases, Joint pain, Lameness, and neurological disorders can occur.

DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits., clinical examination, and blood tests that can show signs of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. such as anemia or thrombocytopeniaThrombocytopenia is a condition in which the number of platelets in the blood is lower than normal, increasing the risk of mild to severe Bleeding.. Specific tests such as the ELISA test or PCR are used to detect Anaplasma antibodies or DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity.. Treatment usually includes antibiotics such as doxycycline for two to four weeks, depending on the severity of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. SupportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. measures such as fluid intake and pain management may be necessary.

PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is crucial and involves controlling tick infestation through vet-recommended tick repellents and maintaining the environment to minimize ticks. Research focuses on improving diagnostic methods and understanding disease transmission, as well as developing new treatment strategies and potential vaccines. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is generally good with early diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment.

Causes

Anaplasmosis is caused by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. of the genus Anaplasma, with Anaplasma phagocytophilum being the species most commonly affecting cats. These bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. are obligate intracellular parasites that live and multiply within the host’s white blood cells. This bacterial species is known to cause a disease called Human Granulocytic Anaplasmosis (HGA) in humans and can also infect various mammals, including cats.

The transmission of anaplasmosis occurs mainly through ticks, particularly Ixodes ticks, which are also known as deer ticks. These ticks are widespread in many parts of the world, especially in wooded and grassy areas, which provide an ideal habitat for these parasites. Cats can become infected through the bite of an infected tick, which transfers the bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. into the cat’s bloodstream.

Other potential causes for the spread of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. include blood transfusions and direct contact with infected blood or tissue, although these transmission routes are less common. The prevalence of anaplasmosis varies by geographic location, with regions having high tick populations posing a greater risk.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

Symptoms of anaplasmosis in cats can vary widely and depend on several factors, including the severity of the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and the general health of the affected cat. The most common symptoms include Fever, Lethargy, and loss of appetite. These non-specific symptoms can easily be confused with other diseases, which can make diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. difficult.

Some cats may also show signs of Pain or Stiffness, which can indicate joint inflammation. In more severe cases, blood clotting disorders can occur, manifesting through symptoms such as bruising, Bleeding, or pale gums. An enlarged spleen or liver can also occur and is often detectable during a physical examination.

In rare cases, anaplasmosis can cause neurological symptoms, such as Convulsions or Behavioral changes, indicating involvement of the central nervous systemThe CNS (central nervous system) consists of the brain and spinal cord. It is responsible for processing information and controls most functions of the body and behavior.. These symptoms require immediate veterinary treatment to avoid serious complications.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of anaplasmosis in cats usually begins with a thorough medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits. and a clinical examination by a veterinarian. Due to the non-specific symptoms, it is important to rule out other diseases with similar clinical signs. Blood tests are an important part of the diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and can reveal signs of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. such as anemia or thrombocytopeniaThrombocytopenia is a condition in which the number of platelets in the blood is lower than normal, increasing the risk of mild to severe Bleeding. (a decreased number of plateletsPlatelets, also called thrombocytes, are cells in the blood that play a crucial role in blood coagulation. They help stop Bleeding by forming clots that seal injuries in blood vessels.).

Specific tests to detect Anaplasma antibodies in the blood, such as the ELISA (enzyme-linked immunosorbent assay) test, can also be used. These tests indicate exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats. to the pathogenA pathogen is a microorganism or virus that can cause disease in its host. Pathogens include bacteria, viruses, fungi, and parasites. but do not necessarily indicate an active infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Another diagnostic approach is the direct detection of Anaplasma DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity. using PCR (polymerase chain reaction)The polymerase chain reaction is a molecular biology technique used to replicate and analyze specific DNA sequences. In veterinary medicine, PCR is used for diagnostic purposes, including the identification of pathogens., a sensitive test that can detect the presence of bacterial DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity. in the blood.

Therapy

Treatment for anaplasmosis in cats usually involves administering antibiotics to fight the bacterial infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Doxycycline is the most commonly used antibiotic and generally shows good results in treating this infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.. Treatment typically lasts two to four weeks, depending on the severity of the disease and the cat’s response to the therapy.

In addition to antibiotic treatment, supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. measures may be necessary, especially for severely ill cats. These may include administering fluids to treat or prevent dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse., pain management, and, if necessary, treating secondary infections. In severe cases, a blood transfusion may also be necessary to treat serious complications such as anemia.

Prognosis and follow-up care

The prognosis for cats with anaplasmosis depends on various factors, including the cat’s health status before the infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., the severity of the symptoms, and the timing of diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment. In most cases, cats respond well to antibiotic treatment, and symptoms usually improve quickly once therapyTherapy refers to the treatment of diseases or disorders with the aim of alleviating symptoms, promoting healing, or improving quality of life. Therapies can be medicinal, surgical, or through other medical interventions. has begun.

With early diagnosis and appropriate treatment, the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. is generally good, and many cats recover completely without permanent damage. If left untreated, however, the disease can lead to serious complications that can significantly affect the cat’s quality of life.

Prevention

To minimize the risk of anaplasmosis infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. in cats, tick control is crucial. Regular use of vet-recommended tick repellents can help prevent tick infestation and thus reduce the risk of Anaplasma transmission. These products are available in various forms, including spot-on treatments, collars, and oral medications.

Additionally, the cat’s environment should be maintained regularly to minimize ticks. This includes mowing the grass, removing leaves, and trimming shrubs. These measures reduce the likelihood of ticks getting near the cat. If the cat has outdoor access, it is advisable to check them for ticks after every outdoor stay and remove them immediately.

Another way to lower the risk of infection is to limit the cat’s access to areas with high tick density, especially during tick season. Pet owners should also regularly talk to their veterinarian about the latest prevention strategies and products to ensure the best protectionProtection refers to safeguarding against diseases or harm. In veterinary medicine, this can include protecting animals through vaccinations, the use of parasite control products, or providing a safe environment. strategy for their cat.

Outlook on current research

Anaplasmosis in cats is an emerging field of research, as this disease was mainly studied in dogs and other animals in the past. Researchers are focusing on better understanding the prevalence of anaplasmosis in cats and identifying the specific species of Anaplasma that infect cats. Most studies so far have shown that Anaplasma phagocytophilum is the most common species affecting cats, but there is evidence that other species might also play a role.

A focus of current research is on improving diagnostic methods. Traditionally, serological tests were used to detect antibodies against Anaplasma in the blood. However, these tests cannot distinguish between a current infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. and a previous exposureExposure refers to the Contact with or subjection to certain substances, environmental factors, or pathogens. In veterinary medicine, this can include Contact with toxins, allergens, or infectious agents that can cause health problems in dogs and cats.. Therefore, scientists are working on developing molecular diagnostic procedures such as PCR (polymerase chain reaction)The polymerase chain reaction is a molecular biology technique used to replicate and analyze specific DNA sequences. In veterinary medicine, PCR is used for diagnostic purposes, including the identification of pathogens., which can directly detect the presence of Anaplasma DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity..

Another important field of research is the study of the carriers of Anaplasma. Ticks are the main carriers of these parasites, but there are still open questions about the specific tick species relevant to cats. Studies on the distribution and behavior of these ticks help improve the understanding of disease transmission and can contribute to the development of better preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies.

There are also ongoing investigations into the effectiveness of various treatment options. Doxycycline is the most commonly used antibiotic for treating anaplasmosis in cats, but researchers are testing other treatment options to avoid resistanceResistance refers to the ability of microorganisms to withstand the effects of antibiotics, antifungals, or other antimicrobial drugs. Resistance can also refer to the body's ability to be insensitive to diseases or toxins. and increase treatment efficiency. Some studies are looking at combinations of antibiotics or the use of new medications that could allow for a faster and more complete recovery.

Finally, the role of the felineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. in anaplasmosis infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. is another area of research. Scientists are trying to find out why some cats become more severely ill than others, which could lead to a better understanding of the immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens. and potential vaccineA vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens. developments. Genetic predispositionA predisposition is an innate inclination or susceptibility of an organism to certain diseases or conditions. In dogs and cats, there may be a genetic predisposition to certain conditions such as hip dysplasia or certain heart diseases. and the influence of environmental factors are also the subject of current studies aimed at identifying risk factors for the disease.

Frequently asked questions (FAQs)

What is Anaplasmosis in cats? Anaplasmosis is a disease caused by bacteriaBacteria are microscopic, single-celled organisms that exist in almost every environment on Earth. Some types of bacteria are beneficial or even essential to life, while others can cause disease. of the genus Anaplasma. It is mainly transmitted by ticks and can cause a variety of symptoms, including Fever, Lethargy, and loss of appetite.
How is Anaplasmosis diagnosed in cats? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is usually made through blood tests that detect antibodies against Anaplasma. Molecular tests like PCR can also be used to directly detect the presence of Anaplasma DNADNA (deoxyribonucleic acid) is the molecule that carries the genetic instructions for the development, function, and reproduction of all known living organisms and many viruses. It is located in the cells of an organism and contains the information for heredity..
What symptoms occur in an infected cat? Symptoms include Fever, Lethargy, loss of appetite, Joint pain, and in some cases, neurological problems. However, symptoms can be variable, and some cats may show only mild or no symptoms at all.
How is Anaplasmosis treated in cats? The standard treatment for anaplasmosis is the administration of antibiotics, mainly doxycycline. Treatment usually lasts several weeks, and most cats recover completely if the disease is detected and treated early.
Is Anaplasmosis in cats contagiousContagious means infectious. Diseases that can easily be transmitted from one animal to another or from animals to humans are referred to as contagious. to humans or other animals? While humans can also get anaplasmosis, transmission does not occur directly from cats to humans. However, both can be infected by the same tick bite. Precautions against tick bites are therefore important.
Can all cats get Anaplasmosis? Yes, basically all cat species can get anaplasmosis, especially if they live in areas where ticks are common. Outdoor cats have a higher risk of becoming infected through tick bites.
Is there a way to prevent Anaplasmosis in cats? The best preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is to avoid tick bites. This can be achieved by using tick repellents, regular tick checks, and avoiding tick-infested areas. In addition, cats should be regularly examined for signs of infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease..
How quickly do symptoms appear after infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.? Symptoms can appear a few days to weeks after the tick bite. The incubation periodThe incubation period is the time between infection with a pathogen and the appearance of the first symptoms. This period can vary depending on the pathogen and individual immune response. is variable and depends on several factors, including the cat’s immune responseAn immune response is the immune system's reaction to foreign substances (antigens), such as microorganisms or proteins. It involves a series of processes aimed at recognizing, fighting, and eliminating these antigens..
Can a cat develop immunityImmunity is the body's ability to protect itself against infections, diseases, or foreign substances. It can be natural, as with innate immunity, or acquired, as with adaptive immunity, which develops after an infection or vaccination. after an Anaplasmosis infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease.? There is evidence that cats can develop some immunityImmunity is the body's ability to protect itself against infections, diseases, or foreign substances. It can be natural, as with innate immunity, or acquired, as with adaptive immunity, which develops after an infection or vaccination. after an infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease., but this may not be complete or permanent. Re-infection is therefore possible.
What long-term consequences can Anaplasmosis have in cats? With timely and appropriate treatment, most cats recover completely without long-term consequences. If left untreated, however, the disease can lead to serious health problems, including chronicChronic refers to a condition or disease that is long-lasting or permanent. Chronic diseases often develop slowly and can lead to persistent or recurring health problems over time. Pain and organ damage.

Frequently asked questions (FAQs)

1. What is Anaplasmosis in cats?

Anaplasmosis is a disease caused by bacteria of the genus Anaplasma. It is mainly transmitted by ticks and can cause a variety of symptoms, including Fever, Lethargy, and loss of appetite.

2. How is Anaplasmosis diagnosed in cats?

Diagnosis is usually made through blood tests that detect antibodies against Anaplasma. Molecular tests like PCR can also be used to directly detect the presence of Anaplasma DNA.

3. What symptoms occur in an infected cat?

Symptoms include Fever, Lethargy, loss of appetite, Joint pain, and in some cases, neurological problems. However, symptoms can be variable, and some cats may show only mild or no symptoms at all.

4. How is Anaplasmosis treated in cats?

The standard treatment for anaplasmosis is the administration of antibiotics, mainly doxycycline. Treatment usually lasts several weeks, and most cats recover completely if the disease is detected and treated early.

5. Is Anaplasmosis in cats contagious to humans or other animals?

While humans can also get anaplasmosis, transmission does not occur directly from cats to humans. However, both can be infected by the same tick bite. Precautions against tick bites are therefore important.

6. Can all cats get Anaplasmosis?

Yes, basically all cat species can get anaplasmosis, especially if they live in areas where ticks are common. Outdoor cats have a higher risk of becoming infected through tick bites.

7. Is there a way to prevent Anaplasmosis in cats?

The best prevention is to avoid tick bites. This can be achieved by using tick repellents, regular tick checks, and avoiding tick-infested areas. In addition, cats should be regularly examined for signs of infection.

8. How quickly do symptoms appear after infection?

Symptoms can appear a few days to weeks after the tick bite. The incubation period is variable and depends on several factors, including the cat's immune response.

9. Can a cat develop immunity after an Anaplasmosis infection?

There is evidence that cats can develop some immunity after an infection, but this may not be complete or permanent. Re-infection is therefore possible.

10. What long-term consequences can Anaplasmosis have in cats?

With timely and appropriate treatment, most cats recover completely without long-term consequences. If left untreated, however, the disease can lead to serious health problems, including chronic Pain and organ damage.