Babesia microti is a parasitic blood-borne

piroplasm Piroplasmida is an order of parasites in the phylum Apicomplexa. They divide by binary fission and as sporozoan parasites they possess sexual and asexual phases (sexual reproduction occurs in the tick gut). They include the tick parasites ''Ba ...

transmitted by deer ticks. ''B. microti'' is responsible for the disease

babesiosis Babesiosis or piroplasmosis is a malaria-like parasitic disease caused by infection with a eukaryotic parasite in the order Piroplasmida, typically a ''Babesia'' or '' Theileria'', in the phylum Apicomplexa. Human babesiosis transmission via ...

, a

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

-like disease which also causes fever and

hemolysis Hemolysis or haemolysis (), also known by several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may occur in vivo o ...

Life cycle

The life cycle of ''B. microti'' includes human red blood cells and is an important transfusion-transmitted infectious organism. Between 2010 and 2014 it caused four out of fifteen (27%) fatalities associated with transfusion-transmitted microbial infections reported to the

US FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...

(the highest of any single organism). In 2018, the

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

approved an antibody-based screening test for blood and organ donors. An important difference from malaria is that ''B. microti'' does not infect liver cells. Additionally, the piroplasm is spread by tick bites (''

Ixodes scapularis ''Ixodes scapularis'' is commonly known as the deer tick or black-legged tick (although some people reserve the latter term for '' Ixodes pacificus'', which is found on the west coast of the US), and in some parts of the US as the bear tick. It w ...

'', the same tick that spreads

Lyme disease Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the ''Borrelia'' bacterium, which is spread by ticks in the genus ''Ixodes''. The most common sign of infection is an expanding red rash, known as erythema migran ...

), while the malaria protozoans are spread via mosquito. Finally, under the microscope, the merozoite form of the ''B. microti'' lifecycle in red blood cells forms a cross-shaped structure, often referred to as a " Maltese cross" or tetrad, in addition to intracellular "ring forms" which are also seen in the malaria parasite (''

Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a vert ...

'' spp.).

Taxonomy

Until 2006 ''B. microti'' was thought to belong to the genus ''

Babesia ''Babesia'', also called ''Nuttallia'', is an apicomplexan parasite that infects red blood cells and is transmitted by ticks. Originally discovered by the Romanian bacteriologist Victor Babeș in 1888, over 100 species of ''Babesia'' have since ...

'', as ''Babesia microti'', until

ribosomal RNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal ...

comparisons placed it in the sister genus ''

Theileria ''Theileria'' is a genus of parasites that belongs to the phylum Apicomplexa, and is closely related to ''Plasmodium''. Two ''Theileria'' species, ''T. annulata'' and ''T. parva'', are important cattle parasites. ''T. annulata'' causes tropical ...

''. , the medical community still classified the parasite as ''Babesia microti'' though its genome showed it does not belong to either ''Babesia'' or ''Theileria''.

Genomics

The genome of ''Babesia microti'' has been sequenced and published. The mitochondrial genome is circular.

Vaccine

In May 2010, it was reported that a vaccine to protect cattle against

East Coast fever East Coast fever, also known as theileriosis, is a disease of cattle which occurs in Africa and is caused by the protozoan parasite ''Theileria parva''. The primary vector which spreads ''T. parva'' between cattle is a tick, ''Rhipicephalus appe ...

had been approved and registered by the governments of Kenya, Malawi and Tanzania. A vaccine to protect humans has yet to be approved.

References

External links

Babesia microti
Minnesota Department of Health {{Taxonbar, from=Q7777786 Piroplasmida