8.+The+Apicomplexa+Toxoplasma+etc

8.+The+Apicomplexa+Toxoplasma+etc - TheApicomplexans...

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The Apicomplexans Plasmodium spp. Babesia spp. Toxoplasma gondii Cryptosporidium parvum Isospora belli Cyclospora cayetanensis
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Babesia spp.   Babesia bigemina  Babesia microti  Babesia gibsoni  Babesia divergens 
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infect red blood cells (RBCs) closely related to malarias transmitted by bite of ticks  mild fever  OR  severe, life-threatening illness  depends on species   babesiosis in humans is rare classified as an  emerging infection   each species has numerous reservoir hosts  Babesia  spp.
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Babesia bigemina  occasionally infects humans ( primarily infects cattle agent of Texas cattle fever  in southwestern US   extensive economic loss Babesia microti  most common species infecting humans in US  Babesia gibsoni  infects dogs  some human cases reported  Babesia divergens  most frequent species in Europe  considered an  emerging infection Babesia  spp. Many species overlap in geographic  distribution but  have discrete ecological niches determined  by tick species 
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Infected tick takes a blood meal from a susceptible mammal  Sporozoites introduced into host  within  salivary secretions of the tick   can also be acquired by  blood transfusion  sporozoites infect red blood cells  induces parasitophorous vacuole formation  vacuole breaks down  organism free in red cell cytosol  Trophozoite ( feeding stage  merozoite ( infectious ) This cycle is similar to growth of Plasmodium in RBCs Difference :   Plasmodium --  in parasitphorous vacuole Babesia --  is free in cytoplasm Schizogeny :  multiple nuclear divisions leading to formation  of  merozoites after cytokinesis Babesia  Lifecycle
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Babesia  Lifecycle In contrast with Plasmodium (also infects red cells) Babesia does  not discard hemazoin  within red cells    high levels of parasitized red blood cells  some merozoites  differentiate into  gametocytes   new tick infected during blood meal gametocytes (1N)   gametes (1N)   zygote (2N) sexual cycle 2 weeks after ingesting organisms   Zygote (2N)   ookinete ( contain infectious sporozoites (1N) ) migrates to salivary glands ookinete   sporozoites (in salivary glands) Tick feeds on mammal   introduces infectious sporozoites 
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Babesia  Lifecycle
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Babesia  Lifecycle
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induces high fever in adults  •immunocompetent patients  self-limiting disease (2-4 weeks)  fever, malaise, headache, lymphopenia often co-infected with other tick-borne pathogens ( Borrelia bergdorferi Ehrlichia  species)  Babesia divergens  causes severe pathogenesis intravascular hemolysis   may necessitate whole body transfusion AIDS patients : may develop long-term chronic infections  Patients without spleens : greatest risk of dying from babesiosis 
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8.+The+Apicomplexa+Toxoplasma+etc - TheApicomplexans...

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