Human Granulocytic Anaplasmosis: Causes, Symptoms, Diagnosis, Treatment, and Prevention

Human Granulocytic Anaplasmosis (HGA) is a tick-borne illness caused by the bacterium Anaplasma phagocytophilum. This article provides a detailed explanation of HGA, including its causes, symptoms, diagnosis, treatment, frequently asked questions (FAQs), and prevention strategies.

Causes of Human Granulocytic Anaplasmosis:

HGA is transmitted through the bite of infected black legged ticks, commonly found in wooded and grassy areas. These ticks become infected when they feed on animals carrying the A. phagocytophilum bacterium. Subsequently, they can transmit the bacterium to humans through their bites. Once inside the body, the bacterium targets and multiplies within white blood cells.

Symptoms Of Human Granulocytic Anaplasmosis:

Typically appearing one to two weeks after a tick bite, HGA symptoms resemble those of the flu, including fever, chills, headache, muscle aches, fatigue, and, occasionally, nausea. Severity varies, with some experiencing mild symptoms and others facing more pronounced illness. In severe cases, the infection can progress to affect other organs, leading to more serious complications.

Diagnosis Of Human Granulocytic Anaplasmosis:

The diagnosis of Human Granulocytic Anaplasmosis involves a combination of clinical assessment, medical history review, and laboratory tests. Physicians may consider the patient’s history of exposure to tick prone areas. Blood tests are used to detect A. phagocytophilum antibodies or DNA. Commonly used tests include polymerase chain reaction (PCR) and serologic tests. These tests help differentiate HGA from similar conditions and confirm the diagnosis.


Early detection and timely treatment are important in other to prevent complications. HGA is often treated with antibiotics, such as doxycycline. Patients typically experience improvement within a few days of beginning treatment. It is important to complete the full antibiotic dosage as prescribed by the healthcare provider to ensure the infection is fully eradicated. In severe cases or instances of compromised immune systems, hospitalization and intravenous antibiotics may be necessary.

Frequently Asked Questions (FAQs)

Can I get Human Granulocytic Anaplasmosis from other sources apart from ticks?

HGA is primarily transmitted through tick bites. No other common sources have been identified as a significant mode of transmission.

What are the symptoms of severe HGA cases?

Severe cases of HGA can lead to respiratory distress, organ failure, and, in rare cases, death. Timely treatment is important in other to prevent such complications.

Are there long term effects of Human Granulocytic Anaplasmosis?

While most people recover fully with appropriate treatment, some individuals might experience lingering fatigue or other symptoms. Regular follow up with a healthcare provider is important.

Can Human Granulocytic Anaplasmosis affect children and the elderly differently?

HGA can affect individuals of all ages, but children, the elderly, and those with weakened immune systems might be more susceptible to severe complications.

Is Human Granulocytic Anaplasmosis a global concern?

HGA is prevalent in certain regions of North America, Europe, and Asia. Travelers to these areas should be aware of the risks and take preventive measures.

How can I safely remove a tick?

Use fine tipped tweezers to grasp the tick as close to the skin’s surface as possible. Pull upward with steady, even pressure. Clean the bite area and your hands with rubbing alcohol or soap and water.


To reduce the risk of HGA, individuals should take steps to prevent tick bites. This includes wearing protective clothing, applying tick repellents, conducting thorough tick checks, and always removing attached ticks. Showering within a few hours of outdoor activities can help wash away unattached ticks. Regularly maintaining outdoor areas can also minimize tick habitats.


Human Granulocytic Anaplasmosis is a tick-borne disease with a range of symptoms that can lead to severe complications if not treated on time. Understanding its causes, symptoms, diagnosis, treatment, and prevention measures empowers individuals to protect themselves from this potentially serious infection. Through awareness and proactive measures, the risk of HGA can be significantly reduced, allowing individuals to enjoy outdoor activities while safeguarding their health.