Babesiosis is a life-threatening infection of the red blood cells that is transmitted by ticks. It is caused by a tiny parasite babesia. There are different species of Babesia that affects humans, Babesia microti being the most predominant. This parasitic infection is most common in the United States and parts of Europe and also observed infrequently across the world during hot weathers. Most people infected with Babesia do not show any symptoms and once diagnosed it can be effectively treated.
Bebesiosis causes symptoms and treatment


People can get infected with Babesia parasites in several ways which include:

The tick bite is the most common cause of developing babesiosis infection during outdoor activities in regions where Babesia parasite is found. Blacklegged (also known as deer) ticks are likely to be carrying Babesia microti parasite.

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A less common way is by getting a blood transfusion from a Babesia infected donor but who does not have any symptoms when donated.

In a very rare case of congenital transmission from an infected mother to her new-born during pregnancy or delivery.

This parasitic infection does not spread from person-to-person like the flu or the common cold.

How It’s Transmitted?

Babesia microti is transmitted in nature by type of lxodes scapularis ticks which is commonly known as blacklegged ticks or deer ticks.

The parasite is transmitted by the young nymph stage of the tick, which quest for a blood meal during summer or spring months in the woods, brush or grass regions.

Infected people may not recognise a tick bit, because the l.scapularis nymphs are very tiny (about a size of the poppy seed).


The severity of the symptoms can vary, some people may have no symptoms at all, while others may have mild flu-like symptoms. The most common symptoms include:

High fever


Muscle or joint pain


Less common symptoms include:

Intense headache

Abdominal cramp


Skin bruising

Yellowing of the skin and eyes

Mood fluctuations

As the infection advances the patient may develop chest pain, breathing difficulty, shortness of breath and profuse perspiration. If a person develop a relapsing high-grade fever, then it is an indication of undiagnosed babesiosis.

Also Read: Infectious Diseases: Causes, Symptoms And Treatment

Risk Factors

People with a compromised immune system and with no spleen are at a higher risk of developing babesiosis. It can be a life-threatening condition for these people, as well as older adults with other comorbid conditions.

Complications Include:

Low blood pressure

Liver failure

Respiratory problems

Haemolytic anaemia

Kidney and Heart failure

Diagnosis And Treatment

Babesia infection can be difficult to diagnose as the symptoms often mimics with many other health conditions. In the early stages, the parasite can be identified by evaluating the blood sample under a microscope. Diagnosis by blood smear microscopy needs time and much skill and knowledge about the nature of the parasites. Smear can show the negative result if there is a low level of parasitemia in the blood, especially in the initial stages of the infection and they may have to repeat the test over several days.

If the doctors suspect babesiosis, then further tests are suggested which include indirect fluorescent antibody test (IFA) and polymerase chain reaction (PCR) test may also be done to confirm the diagnosis.

Generally, the doctors in most cases diagnose babesiosis when a person does not have any other diagnosable medical condition. Furthermore, if a person has a risk factor, like having visited outdoors in regions where ticks carry the parasite or person having received a blood transfusion, then the doctor may suggest for the blood work.


People without any symptoms or signs of babesiosis usually do not require any treatment. However, in a person with symptoms and those who are at risk of developing severe infection due to other chronic medical conditions, the doctor may recommend anti-parasitic drugs to treat mild to moderate cases and it is usually taken for 7-10 days.

However, the treatment for severe infection consists of intravenous and oral drugs. Moreover, a doctor may also suggest supportive medications and therapies to treat severe illness which include:

Blood transfusion

Medication to bring down the fever

Haemodialysis to filter impure blood

Drugs to maintain blood pressure


Avoiding contact with tick is the best possible way to prevent babesiosis. If you happen to visit into wooded and brushes areas where deer ticks are present follow these precautionary measures:

Hike on cleared tracks only, as it will prevent brushing up against brush, grasses and leaf piles where ticks are usually found.

Always wear long socks, pants and long-sleeved t-shirts when visiting outdoors to minimize the chance of tick bite.

Carefully apply tick repellents to the skin or clothing, such as DEET or permerthin containing repellent products. However, these are not suitable for children.

Generally, a tick needs to stay on a person’s body for about 36-48 hours before it can spread the B.microti parasite, hence it is important to thoroughly check on the person body once they have been outside.