Home » Diseases » In dogs » Rickettsiosis, Rocky Mountain spotted fever (bacterial infection caused by the rickettsial species Rickettsia rickettsii)

Rickettsiosis, Rocky Mountain spotted fever (bacterial infection caused by the rickettsial species Rickettsia rickettsii) in Dogs

Synonyms: Flea-borne spotted fever, tick-borne fever

Occurrence: very rare
Location of disease: General/Whole body

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

When to visit the vet?

Urgent see a veterinarian within 24 hours

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

Definition

Rickettsiosis, known as Rocky Mountain spotted fever, is a life-threatening 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. in dogs caused by the bacterium Rickettsia rickettsii and transmitted mainly by ticks.

The most important facts at a glance

Rickettsiosis, especially Rocky Mountain spotted fever, is 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. in dogs caused by the bacterium Rickettsia rickettsii. 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 intracellular and infect the cells of the blood vessels, leading to vasculitisVasculitis is the inflammation of blood vessels, leading to changes in the vessel walls, including thickening, weakening, narrowing, and sometimes the formation of aneurysms or blood clots.. The main vectors are ticks, especially the American dog tick and the Rocky Mountain wood tick. The disease occurs more frequently in warmer months when ticks are more active. Symptoms include Fever, Vomiting, skin redness, Weight loss, and neurological problems. 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. requires clinical signs, 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 specific tests such as antibodyAn antibody is a protein produced by the immune system to recognize and bind specific antigens. By binding to the antigen, antibodies can help destroy or neutralize it. tests or PCR to detect the bacteria’s genetic material. Treatment is mainly with the antibiotic doxycycline, and early treatment is crucial for a good 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.. PreventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. is possible with tick preventatives and regular tick checks. Research focuses on improving diagnostic techniques, investigating transmission routes, and developing new treatment methods. Research is being driven by the increase in ticks and awareness of vector-borne diseases. International collaboration is crucial to better understand the disease and develop effective control measures, especially in light of global warming and changes in tick distribution.

Causes

Rickettsiae are obligate intracellular 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., meaning they must live inside cells to survive and reproduce. Rickettsia rickettsii belongs to a group of 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. known as rickettsiae and is responsible for rickettsiosis in dogs. 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. infect the cells lining the blood vessels, leading to inflammation of the vessels known as vasculitisVasculitis is the inflammation of blood vessels, leading to changes in the vessel walls, including thickening, weakening, narrowing, and sometimes the formation of aneurysms or blood clots..

The primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. source of transmission of Rickettsia rickettsii is ticks. The American dog tick (Dermacentor variabilis) and the Rocky Mountain wood tick (Dermacentor andersoni) are the main carriers of 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. in North America. When an infected tick bites a dog, 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. can enter the dog’s bloodstream.

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. can occur seasonally because ticks are more active in warmer months. Dogs that live in or near wooded or grassy areas, or spend time there, are at higher risk of being bitten by an infected tick.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

Lethargy

The symptoms of rickettsiosis in dogs can vary widely and be nonspecific, 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. Common symptoms include Fever, lethargy, loss of appetite, swollen lymph nodes, and Pain in the joints or muscles. These symptoms can appear within a few days after the tick bite.

In more severe cases, Bleeding may occur, which can present as nosebleeds, bloody urine, or bloody stools. Neurological symptoms such as ataxia (Coordination disorders), Convulsions, or Behavioral changes can also occur if 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. is affected.

The dog’s skin may also be affected, with possible signs of rashes or small Bleeding under the skin (petechiaePetechiae are small, pinpoint skin hemorrhages caused by blood leaking from the capillaries. They can indicate a variety of conditions, including infections, allergic reactions, and blood clotting disorders.). In severe cases, 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. can lead to acuteAcute refers to a condition that occurs suddenly and is usually of short duration. In a medical context, it describes symptoms or illnesses that can quickly become serious and require immediate attention. renal failure or other life-threatening complications.

Diagnosis

Diagnosing rickettsiosis in dogs requires a combination of clinical signs, 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 specific diagnostic tests. A blood testA blood test is a laboratory procedure in which blood is drawn and analyzed to obtain information about the body's health. It can include various parameters such as blood sugar, blood count, liver and kidney values. that detects antibodyAn antibody is a protein produced by the immune system to recognize and bind specific antigens. By binding to the antigen, antibodies can help destroy or neutralize it. against Rickettsia rickettsii can be helpful in supporting 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.. However, it can take a few weeks for antibodyAn antibody is a protein produced by the immune system to recognize and bind specific antigens. By binding to the antigen, antibodies can help destroy or neutralize it. to become detectable, which makes 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. in the early stages of the disease more difficult.

Another diagnostic approach is polymerase chain reaction (PCR), which can detect the genetic material of Rickettsia rickettsii in blood or tissue samples. This method is specific and can enable 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., but it is not always available in all veterinary clinics.

In addition, blood tests may be performed to look for signs of anemia, 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. (low platelet count), or changes in liver and kidney values, which can indicate the effects 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. on different organ systems.

Therapy

Treatment of rickettsiosis in dogs is primarily by administering antibiotics. Doxycycline is the most commonly used antibiotic and is usually given for at least two weeks. Prompt treatment is crucial to avoid complications and improve the chances of recovery.

In severe cases, supportiveSupportive refers to supportive treatments that aim to alleviate symptoms and improve quality of life without directly treating the underlying cause of the disease. 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. may be needed, including intravenous fluids to 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. and medication to control Pain or other symptoms. More intensive treatment may be necessary if there are neurological symptoms or severe anemia.

It is important to start treatment as early as possible, even before all diagnostic test results are available—especially if the clinical suspected 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. strongly suggests rickettsiosis. Delaying treatment can significantly increase the risk of complications.

Prognosis and follow-up care

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. for dogs with rickettsiosis depends heavily on how quickly the disease is diagnosed and treated. With early detection 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 usually good, and many dogs recover fully.

In dogs that are severely ill or where treatment was delayed, 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. may be worse. Complications such as renal failure, severe Bleeding, or neurological damage can reduce the chances of survival and lead to long-term health problems.

Long-term follow-up and regular veterinary check-ups may be necessary to monitor the dog’s health and detect and treat possible late effects 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..

Prevention

The best way to prevent rickettsiosis in dogs is to prevent tick bites. This can be done by using tick preventatives that are applied to the dog regularly and repel or kill ticks.

Regularly checking the dog for ticks after walks in wooded or grassy areas is also important. Ticks should be removed as quickly as possible, as transmission of Rickettsia rickettsii usually occurs several hours after the tick bite.

In addition, avoiding known tick areas or keeping the dog on a leash in high-risk areas can help reduce the risk of a tick bite. It is also important to keep the dog’s environment free of ticks by keeping grass short and removing accumulations of leaves.

Outlook on current research

Rickettsiosis, especially Rocky Mountain spotted fever, is a disease that has increasingly become a focus of veterinary research in recent years. This 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., caused by Rickettsia rickettsii, is transmitted mainly by ticks and can cause serious health problems in dogs. Research is currently focusing on various aspects of the disease, including developing improved diagnostic methods, investigating transmission routes, and finding effective treatment options.

A major research focus is improving diagnostic techniques. Early detection is crucial for successfully managing the disease, as delayed intervention can lead to serious complications. Scientists are working on developing rapid tests and molecular diagnostic tools that make it possible to identify 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. at an early stage. These advances could significantly improve 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. for affected dogs by enabling faster, more targeted treatment.

Another important area of research is investigating the transmission dynamics of the disease. While ticks are known to be the main vectors, many questions remain about how 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. spread within tick populations and which environmental factors influence the prevalence of the disease. Researchers are studying the genetic diversity of Rickettsia rickettsii as well as the role of wildlife and domestic animals as reservoirs for 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.. These findings could help develop effective preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. strategies to minimize the risk of transmission to dogs and humans.

Regarding the treatment of rickettsiosis, one focus is on developing new antibiotics or alternative therapeutic approaches. Because rickettsiae are intracellular 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. that live within their hosts’ cells, treating them is often complicated. Researchers are evaluating the effectiveness of various antibiotics and investigating whether combination therapies or new drug classes could offer better chances of recovery. In addition, efforts are underway to better understand dogs’ 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. to 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 possibly develop vaccines that could protect animals from 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..

Research into rickettsiosis in dogs is being further driven by the increasing threat from ticks and growing awareness of vector-borne diseases. International collaboration and the sharing of data and resources are crucial to better understand the disease and develop more effective control measures. In view of global warming and the associated changes in the distribution of tick populations, research in this area is likely to become even more important in the coming years.

Frequently asked questions (FAQs)

What is rickettsiosis in dogs?

Rickettsiosis is an infectious disease caused by bacteria of the genus Rickettsia. In dogs, it is often triggered by Rickettsia rickettsii, which causes Rocky Mountain spotted fever. These bacteria are transmitted mainly through tick bites. -

What symptoms does a dog show with a rickettsiosis infection?

Symptoms can vary, but often include Fever, loss of appetite, lethargy, Joint pain, Cough, Vomiting, and in severe cases neurological symptoms. Because these signs are nonspecific, an accurate diagnosis is important. -

How is rickettsiosis diagnosed in dogs?

Diagnosis is usually made through a combination of clinical signs, blood tests, and serological tests to detect antibody against rickettsiae. In some cases, molecular tests such as PCR can be used to identify the bacteria. -

How is the disease treated?

Treatment usually consists of giving antibiotics such as doxycycline for several weeks. Early treatment is crucial for success, as it can reduce the severity of symptoms and prevent complications. -

Can dogs fully recover after a rickettsiosis infection?

Yes, with timely and appropriate treatment, dogs can recover fully. Without treatment, however, the disease can cause serious health problems or even be fatal. -

How can rickettsiosis be prevented in dogs?

The best prevention is to avoid tick bites. This can be achieved by using tick preventatives, regularly checking for and removing ticks, and avoiding areas with high tick populations. -

Is rickettsiosis transmissible to humans?

Rickettsiosis is not transmitted directly from dog to human. However, people can also become infected through tick bites, so precautions to avoid tick bites are important for humans as well. -

Is there a vaccine against rickettsiosis for dogs?

There is currently no approved vaccine against rickettsiosis for dogs. However, research is working on developing potential vaccines that could provide protection in the future. -

Which dogs are particularly at risk for rickettsiosis?

Dogs that live in areas with high tick populations or spend a lot of time outdoors are particularly at risk. Dogs with a weakened immune system may also be more susceptible to infection. -

How should dog owners react if they find ticks on their dog?

If dog owners find ticks on their pet, they should remove them as quickly as possible to minimize the risk of infection. The tick should be grasped close to the skin with fine tweezers or a special tick-removal tool and carefully pulled out.