Ehrlichiosis

What is Ehrlichiosis?

The Ehrlichia group includes various kinds of bacteria that live inside cells, which can only survive in other organisms. These bacteria are harmful and can infect humans and other animals through a tick bite. When it comes to symptoms and areas where they’re common, Ehrlichia infections are very similar to infections caused by another type of bacteria called rickettsial. So, if a patient comes in with flu-like symptoms in areas where these infections are common, these bacteria could also be considered a potential cause.

What Causes Ehrlichiosis?

Ehrlichia is a type of bacteria that includes species like Ehrlichia chaffeesis and Ehrlichia ewingii. The first type causes a disease in humans called human monocytic ehrlichiosis (HME) and the latter causes a similar disease. Other species, such as Ehrlichia canis and Ehrlichia ruminantium, typically affect animals like dogs and cattle, but can also infect humans on rare occasions. There’s also a newly identified species called EMLA (Ehrlichia muris-like agent) that’s been linked to human disease.

These bacteria are tricky; they live inside the cells and are transmitted through tick bites. What’s more, they can multiply both in the tick and in their host. In addition to humans, Ehrlichia can infect a variety of hosts including dogs, cattle, sheep, goats, rodents, and deer.

Risk Factors and Frequency for Ehrlichiosis

Ehrlichia, a type of infection often carried by ticks, is being diagnosed more frequently. This could be due to doctors becoming more aware of the condition, better tests for finding it, or the areas where the most common tick carrier (the Lone Star tick) lives expanding. In the United States, most cases of Ehrlichia are caused by a specific type of the bacteria, Ehrlichia chaffeesis, but Ehrlichia ewingii is also found, though less often.

Places where the Lone Star tick is common, such as the South Central United States, are where Ehrlichia infections occur the most. As per data from the Centers for Disease Control and Prevention, over 30% of Ehrlichia infections in the United States have been reported in Oklahoma, Missouri, and Arkansas.

• Ehrlichia cases are most frequently reported during the summer months.
• This is when the adult and young ticks, which are more likely to bite humans, are most active.
• Many reports of this infection are from elderly people.
• Kids can also get Ehrlichia, but their infections are often milder or show no symptoms, which probably leads to fewer reported cases in this age group.

Signs and Symptoms of Ehrlichiosis

Ehrlichia infections, caused by tick bites, usually appear as fever, general discomfort, headache, body aches, and chills. These symptoms are often mistaken for the flu and tend to show up about 1 to 2 weeks after the tick bite. If you have been to areas where this infection is common or have been involved in outdoor activities during the summer, and start experiencing these flu-like symptoms, it’s important to get checked. Recognizing and treating Ehrlichia and other tick-borne diseases early can make them less severe.

Some patients may also experience gastrointestinal issues like nausea, vomiting, diarrhea, and rash. The rash is more common in children and usually appears about 5 days into the illness. It can look like small red or purple spots on the skin, or a widespread skin redness. Adults are more likely to have cough and respiratory symptoms than children are. The central nervous system, including the brain and spinal cord, can also be affected in some cases, leading to conditions such as meningitis and meningoencephalitis, which are inflammations of the brain and spinal cord.

In more severe cases, symptoms can progress to cause a condition known as acute respiratory distress syndrome (ARDS) or a severe body reaction similar to shock, with unstable heart conditions and blood clotting issues. However, death rates from Ehrlichia infections are quite low, with the Centers for Disease Control and Prevention (CDC) reporting rates of 1% to 3% since 2000 for patients who saw a doctor for their symptoms. Keep in mind that some people get infected but don’t seek medical help, so these numbers might not reflect the full picture. People who have weakened immune systems, older adults, and those who have been treated with certain antibiotics are more likely to get severely ill from these infections.

Testing for Ehrlichiosis

If you’re suspected of having a condition called ehrlichiosis, your doctor may look for specific markers in your blood. You could have a low white blood cell count, known as leukopenia, or a low platelet count, called thrombocytopenia. Medical professionals may also detect elevated transaminases, which are enzymes that, when high, can indicate liver damage.

Another potential sign is hyponatremia, which is a lower-than-normal amount of sodium in your blood. Occasionally, doctors can observe abnormal cell structures known as morulae in the blood or other body fluids, but this observation isn’t a definitive diagnosis of ehrlichiosis. Furthermore, in some patients, the fluid that surrounds the brain and spinal cord, known as cerebrospinal fluid, may show an increase in white blood cells and protein levels.

Most often, ehrlichiosis is diagnosed using a method called polymerase chain reaction (PCR). This test is especially beneficial because ehrlichiosis often infects white blood cells that circulate within your bloodstream. However, starting antibiotic treatment with a drug named doxycycline can affect the accuracy of the PCR test, so ideally, samples should be taken before beginning this medication, unless waiting would delay necessary treatment.

Blood tests, known as serology, could be used as well to aid in the diagnosis, but ehrlichiosis is typically not identified using culture tests, which grow and identify bacteria in a controlled lab setting.

Treatment Options for Ehrlichiosis

Doxycycline is a medicine that is often chosen to treat conditions called ehrlichiosis and rickettsial infections. These illnesses are difficult to tell apart in their early stages. While some studies suggested that another medicine called rifampin could be used to treat ehrlichiosis, there is no substantial proof that it works. Moreover, it doesn’t help with rickettsial infections, which are similar to ehrlichiosis. As a result, doxycycline remains the preferred drug for these conditions.

Patients being treated for ehrlichiosis with doxycycline usually start to feel better, with a decrease in fever, within 48 to 72 hours. The treatment usually lasts for 5 to 7 days depending on how ill the patient is. Research has shown that doxycycline rarely causes tooth discoloration at the doses used to treat ehrlichiosis and rickettsial infections. Therefore, concerns about tooth staining in children should not delay the treatment with doxycycline if ehrlichiosis is suspected.

As for preventing ehrlichiosis after being bitten by a tick (the insect that can spread this disease) in areas where the disease is common, there is no current recommendation.

What else can Ehrlichiosis be?

When a doctor is trying to diagnose ehrlichiosis, a type of bacterial illness, they need to make sure it’s not actually one of the following similar illnesses:

• Bacterial sepsis (a life-threatening response to bacterial infection)
• Endocarditis (infection of the heart’s inner lining)
• Hepatitis (inflammation of the liver)
• Influenza (commonly known as the flu)
• Kawasaki disease (a disease that causes inflammation in artery walls)
• Leptospirosis (bacterial disease which can affect humans and animals)
• Murine typhus (a disease caused by a bacteria found in fleas)
• Q fever (an illness caused by the bacteria Coxiella burnetii)
• Toxic shock syndrome (a severe illness caused by a bacterial infection)
• Typhoid fever (a bacterial infection that can spread throughout the body)

What to expect with Ehrlichiosis

Ehrlichiosis, a type of disease commonly spread by ticks, usually improves quickly—within 24 to 48 hours—if diagnosed and treated at an early stage. However, if a person has other health conditions, is severely infected, or if the treatment is delayed, the disease can become serious and in some cases, even deadly.

This is why doctors often start treatment for suspected ehrlichiosis immediately, even before they receive final lab results confirming the disease. This preemptive treatment approach is known as empiric therapy and it is critical to prevent the potentially severe consequences of the disease.

Possible Complications When Diagnosed with Ehrlichiosis

Ehrlichiosis can, in rare cases, cause severe complications especially in people with a weak immune system such as those with HIV or cancer. Serious consequences from this condition comprise:

• Brain-related problems like confusion, seizures, or coma
• Bleeding that can’t be controlled (hemorrhage)
• Failure of the heart
• Failure of respiratory function
• Failure of the kidneys
• Septic shock, a dangerous drop in blood pressure

If these complications occur, they may need to be addressed with additional treatments such as respiratory support, intravenous fluids, or kidney dialysis. This is more commonly seen in elderly individuals or those with existing health issues.

Preventing Ehrlichiosis

People affected by ehrlichiosis, a disease caused by ticks, can’t spread it to others. However, if one person in a group gets it, it’s a sign that others could also catch the disease from ticks in the same area. That’s why it’s crucial for patients to learn how to avoid ticks and take steps to control them.