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Ehrlichia
Ehrlichia are small, obligate intracellular parasites that infect white blood cells, particularly monocytes. They form clusters called morulae within the host cell. Ehrlichia species include E. sennetsu, E. caffeensis, E. phagocytophila, and E. canis. E. sennetsu causes glandular fever in Asia through fish consumption. E. phagocytophila causes human granulocytic ehrlichiosis through Ixodes ticks. E. caffeensis causes human monocytic ehrlichiosis through Amblyomma ticks. Ehrlichiosis is characterized by morulae in infected cells after 5-7 days. Most cases present as a mild acute fever but
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Ehrlichia
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- 2. Introduction Small gram negative,obligate, intracellular parasites These are tiny organisms measuring 0.2-2.4micromtrs. Which have affinity towards WBC particularly mononucslear phagocytes
- 3. Clusters of Ehrlichiamultiply in host cell vacuoles to form large mulbery shaped aggregates called MORULAE Ehrlichia inclusions like morulae are visible in cytoplasm of infected cell after 5-7 days
- 4. Ehrlichia Species Ehrlichia sennetsu Ehrlichiacaffeensis Ehrlichia phagocytophila Ehrlichia cannus
- 5. EHRLICHIA SENNETSU Endemic inJAPAN and SOUTH EAST ASIA It causes GLANDULAR FEVER It shows lymphoid hyperplasia and atypical lymphocytosis No arthropod vector identified Human infection is suspected to be caused by ingestion of fish carrying infected flukes
- 6. EHRLICHIA PHAGOCYTOPHILA Causes humanGRANULOCYTIC EHRLICHIOSIS Transmitted by IXODES ticks Deer, cattle and sheep are suspecte reservoirs Leucopenia and thrombocytopenia observed in patients
- 7. EHRLICHIA CAFFEENSIS Cause humanMONOCYTIC EHRLICHIOSIS Transmitted by Amblyomma ticks Deers and rodents reservoirs Leucopenia and thrombocytopenia increased liver enzymes Most dangerous can cause multisystem failure and fatality
- 8. EHRLICHIOSIS Ehrlichiosis is infectionof WBC that is characterised by mulbery shaped aggregates called morulae in infected cells These morulae are visiible after 5-7days of infection
- 9. Pathophysiology It is notcompletely known Like RICKETTSIA sps EHRLICHIA gain access to blood via bite from infected tick
- 10. AMBLYOMMA AMERICANAM(lone startick) E.chaffeensis IXODES PERSUKATUS DERMACENTOR VARIABILIS (dog tick wood tick)
- 11. The major antigendeterminants are surface membrane protien These are complexes consisting of : 1)thermolabile 2)thermostable Key protien bands associated are: E.phagocytophia - 27,29,44 KD bands E.caffeensis - 40,44,65 KD bands
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- 13. Mortality and morbidity Greatmajority of EHRLICHIOSIS are asymptomatic Most cases present as mild to moderate acute febrile illness In immunocompromised persons ehrliosis may be severe manifesting as ROCKY MOUNTAIN SPOTTED FEVER may be fatal
- 14. Clinical features Rash andpedal edema
- 15. Patients with Ehrlichiosisusually present with head ache, myalgia, fever, shaking chills. Nausea and vomiting are common Abdominal pain is uncommon and is typically mild Skin rash due to ehrlichiosis is rare. When present as macculopapular rash rather than peticheal
- 16. Cont… Some patients developheptomegaly Lymphadenopathy is observed in <25% Splenomegaly is uncommon Patients with severe ehrlichiosis develop thrombocytopenia and disseminated intravascular coaggulation(DIC) which can result in hemorrhage into skin
- 17. Distribution Ehrlichiosis occurs worldwideand frequensy parallels distribution of appropriate tick vector for transmission of ehrlichia and mammalian host In USA it occurs in states of CALIFORNIA, TEXAS and SOUTH EAST NORTHERN REGIONS OF CAENTRY World wide it occurs in JAPAN, SOUTH EAST ASIA
- 18. Lab diagnosis Diagnosis restson 1)single elevated IgG IFA antibody titre 2)demonstration of incr. in acute and convalescent IFA ehrlichia titre Difficult to culture Detection with PCR
- 19. Blood smear forcytoplasmic inclusions CBP for thrombocytopenia and neutropenia Atypical lymphocytes in blood Serum transaminases are mild high DIC may be diagnosed with cutaneous bleeding Lumbar puncture to rule out meningitis
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