Blood worms and blood parasites

There are parasitic animals that infect blood.

With blood, they can reach many parts of human body.

Some parasites can be bloodborne. This means:

https://www.cdc.gov/parasites/blood.html



the parasite can be found in the bloodstream of infected people; and
the parasite might be spread to other people through exposure to an infected person's blood (for example, by blood transfusion or by sharing needles or syringes contaminated with blood).

Examples of parasitic diseases that can be bloodborne include
African trypanosomiasis,
babesiosis,
Chagas disease,
leishmaniasis,
malaria, and
toxoplasmosis.

In nature, many bloodborne parasites are spread by insects (vectors), so they are also referred to as vector-borne diseases. Toxoplasma gondii is not transmitted by an insect (vector).

In the United States, the risk for vector-borne transmission is very low for these parasites except for some Babesia species.


Blood Transfusions

Many factors affect whether parasites that can be found in the bloodstream might be spread by blood transfusion. Examples of some of the factors include:

how much of the parasite’s life cycle is spent in the blood;
how many parasites might be found in the blood (in other words, the concentration or level of the parasite);
how long the parasite stays in the body, in treated and untreated people; and
how the parasite affects people. For example, if infected people feel sick, they might not want to donate blood or they might be deferred (turned away).
Some parasites spend most or all of their life cycle in the bloodstream, such as Babesia and Plasmodium species. Parasites, such as Trypanosoma cruzi, might be found in the blood early in an infection (the acute phase) and then at much lower levels later (the chronic phase of infection). Other parasites only migrate (travel) through the blood to get to another part of the body.

There may be cases of transfusion-transmitted parasites that go undetected and unreported, but the risk for infection is very low compared with the number of blood transfusions. In the United States since 1980, there have been published reports of cases of transfusion-associated babesiosis (>150), malaria (~50), and Chagas disease (~5). Since 1965, there have been published reports of transfusion-associated toxoplasmosis (~4).



https://www.cdc.gov/parasites/blood.html