Babesiosis

Babesiosis is a malaria-like parasitic disease caused by infection with Babesia, a type of Apicomplexa. Human babesiosis transmission via tick bite is most common in the Northeastern and Midwestern United States and parts of Europe, and sporadic throughout the rest of the world. It occurs in warm weather. People can get infected with Babesia parasites by the bite of an infected tick, by getting a blood transfusion from an infected donor of blood products, or by congenital transmission (an infected mother to her baby).Ticks transmit the human strain of babesiosis, so it often presents with other tick-borne illnesses such as Lyme disease. After trypanosomes, Babesia is thought to be the second-most common blood parasite of mammals, and they can have a major impact on health of domestic animals in areas without severe winters. In cattle the disease is known as Texas cattle fever, redwater, or piroplasmosis. Babesiosis is a malaria-like parasitic disease caused by infection with Babesia, a type of Apicomplexa. Human babesiosis transmission via tick bite is most common in the Northeastern and Midwestern United States and parts of Europe, and sporadic throughout the rest of the world. It occurs in warm weather. People can get infected with Babesia parasites by the bite of an infected tick, by getting a blood transfusion from an infected donor of blood products, or by congenital transmission (an infected mother to her baby).Ticks transmit the human strain of babesiosis, so it often presents with other tick-borne illnesses such as Lyme disease. After trypanosomes, Babesia is thought to be the second-most common blood parasite of mammals, and they can have a major impact on health of domestic animals in areas without severe winters. In cattle the disease is known as Texas cattle fever, redwater, or piroplasmosis. Half of all children and a quarter of previously healthy adults are asymptomatic with Babesia infection. When people do develop symptoms, the most common are fever and hemolytic anemia, symptoms that are similar to those of malaria. People with symptoms usually become ill 1 to 4 weeks after the bite, or 1 to 9 weeks after transfusion of contaminated blood products. A person infected with babesiosis gradually develops malaise and fatigue, followed by a fever. Hemolytic anemia, in which red blood cells are destroyed and removed from the blood, also develops. Chills, sweats, and thrombocytopenia are also common symptoms. Symptoms may last from several days to several months. Less common symptoms and physical exam findings of mild-to-moderate babesiosis: In more severe cases, symptoms similar to malaria occur, with fevers up to 40.5 °C (105 °F), shaking chills, and severe anemia (hemolytic anemia). Organ failure may follow, including adult respiratory distress syndrome. Sepsis in people who have had a splenectomy can occur rapidly, consistent with Overwhelming post-splenectomy infection. Severe cases are also more likely to occur in the very young, very old, and persons with immunodeficiency, such as HIV/AIDS patients. A reported increase in human babesiosis diagnoses in the 2000s is thought to be caused by more widespread testing and higher numbers of people with immunodeficiencies coming in contact with ticks, the disease vector. Little is known about the occurrence of Babesia species in malaria-endemic areas, where Babesia can easily be misdiagnosed as Plasmodium. Human patients with repeat babesiosis infection may exhibit premunity. Babesia species are in the phylum Apicomplexa, which also has the protozoan parasites that cause malaria, toxoplasmosis, and cryptosporidiosis. Four clades of Babesia species infect humans. The main species in each clade are: Babesia parasites reproduce in red blood cells, where they can be seen as cross-shaped inclusions (four merozoites asexually budding, but attached together forming a structure looking like a 'Maltese cross') and cause hemolytic anemia, quite similar to malaria. Unlike the Plasmodium parasites that cause malaria, Babesia species lack an exoerythrocytic phase, so the liver is usually not affected. In nonhuman animals, Babesia canis rossi, Babesia bigemina, and Babesia bovis cause particularly severe forms of the disease, including a severe haemolytic anaemia, with positive erythrocyte-in-saline-agglutination test indicating an immune-mediated component to the haemolysis. Common sequelae include haemoglobinuria 'red-water', disseminated intravascular coagulation, and 'cerebral babesiosis' caused by sludging of erythrocytes in cerebral capillaries.