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Babesia microti

Babesia microti. Marcus Williamson Katie Hofkes Kayla Jenness. General Information. Hemoprotozoan infection of the red blood cells Babesiids are pyriform, round, or oval parasites Spread to humans by a tick bite, Ixodes scapularis . General Information.

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Babesia microti

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  1. Babesia microti Marcus Williamson Katie Hofkes Kayla Jenness

  2. General Information • Hemoprotozoan infection of the red blood cells • Babesiids are pyriform, round, or oval parasites • Spread to humans by a tick bite, Ixodes scapularis .

  3. General Information • The disease mostly effects people who are immunocompromised, elderly, or have undergone a splenectomy • Approximately 20% of patients diagnosed with Babesiosis also have Lyme disease from the same deer tick bite. • While more than 100 species of Babesia have been reported, only a few have been identified as causing human infections.

  4. General Information • Their apical complex is reduced to a polar ring, rhoptries, micronemes, and subpellicular microtubules

  5. Geographic Distribution • Is found worldwide • Babesia microti is most commonly found in the Northeast and Midwest in the United States and often in nonsplenectomized patients • In the Northeast: Martha’s Vineyard, Nantucket Island, Cape Cod, Long Island are the most common places • In the Western US, the causative agent of Babesiosis is Babesia gibsoni • There have been cases in Minnesota and Wisconsin as well.

  6. Geographic Distribution Cont’d • Not much is known about Babesia in Malaria-endemic countries • In Europe, most reported cases are from Babesia divergens and is found in splenectomized patients • In the Southern United States, the infection is called Babesia bigemina, which is a disease of cattle • Also called Texas red-water fever

  7. Mortality/Morbidity • Death in the US is uncommon • Most infections are asymptomatic and improve spontaneously without treatment • About 25% of patients with Babesiosis also have Lyme disease • In Europe, Babesiosis is more serious • 84% are asplenic and 53% become comatose and die • Male to Female ratio is 1:1 and it affects all age groups

  8. Hosts • Definitive Host- White footed mouse (Peromyscus leucopus) • Intermediate Host- Deer Tick (Ixodes scapularis) • Accidental Host – Humans (Dead end host) • Deer are the hosts which adult ticks feed on but are indirectly part of the life cycle.

  9. Life Cycle

  10. Life Cycle Cont’d. • During a blood meal, a Babesia infected tick introduces sporozoites into the mouse host • Sporozoites enter the erythrocytes and undergo asexual reproduction • In the blood, some parasites differentiate into male and female gametes • Once ingested by a tick, the gametes unite and undergo a sporogenic cycle resulting in sporozoites

  11. Life Cylce (Cont’d.) • Humans become a part of the cycle when bitten by infected ticks • During a blood meal, the Babesia infected tick gives sporozoites to the human host • Sporozoites enter the erythrocytes and undergo asexual reproduction • Humans are dead end hosts and there is little, if any more transmission that occurs from ticks feeding on infected humans

  12. Pathogenesis/Clinical Signs • Majority of people have no visible symptoms • Fever, chills, sweating, fatigue • Flu-like, tiredness, loss of appetite, muscle pain, nausea, vomiting, headache, shaking chills, blood in urine, and depression can occur. • Hepatosplenomegaly • Hemolytic Anemia • These can occur for several weeks after an incubation period of 1-4 weeks • Those over 40 who have had spleen taken out or have serious disease may end up with 85% blood cells infected which leads to possibly death.

  13. Diagnosis • Early diagnosis can reduce the severity of the illness. • Some people may be infected with more than one tick-borne infection which will make diagnosis more difficult. • Examining thick and thin blood smear samples stained with Giesma is the most common way for diagnosis. • Antibody detection by indirect fluorescent antibody (IFA) test is a diagnostic test. • Isolation of Babesia by inoculation of patients blood into hamsters and gerbils assists in diagnosis also.

  14. Treatment • Treated with antimicrobial drugs. • Combination of clindamycin, quinine, atovaquone, and/or azithromycin • Clindamycin is by injection and quinine given orally 3-4 times a day for 4-7 days. • Exchange transfusions have been used for the severely ill patients.

  15. Control Measure • Avoid tick habitats during the peak time of the year (when deer populations increase) • Stay on trails when walking through the woods. • Avoid tall grasses. • Wear long sleeved shirts and tuck pant legs into socks. • Wear insect repellent. • Check for ticks after an outing.

  16. Tick Removal • Use pair of tweezers to grasp the head of the tick. • Grasp tick close to the skin. • Pull tick outward slowly, gently, steadily. • Do not squeeze the tick. • Use antiseptic on the tick bite.

  17. Pictures Giemsa-stained thin smear

  18. Pictures Cont’d. Note: the absence of pigment, variation in the rings, and the tetrad on the left, which is helpful for diagnosis of B. microti

  19. Pictures Cont’d.

  20. References • http://www.itg.be/itg/DistanceLearning/LectureNotesVandenEndenE/imagehtml/ppages/kabisa_1396.htm • http://www.medterms.com/script/main/art.asp?articlekey=15257 • http://www.dpd.cdc.gov/dpdx/html/Babesiosis.asp?body=Frames/A-F/Babesiosis/body_Babesiosis_page1.htm • http://www.health.state.mn.us/divs/idepc/diseases/babesiosis/basics.html • www.healthatoz.com

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