Introduction  Small gram negative, obligate, intracellular parasites  These are tiny organisms measuring micromtrs. Which have affinity towards WBC particularly mononuclear phagocytes

 Clusters of Ehrlichia multiply 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

Ehrlichia sps  Ehrlichia sennetsu  Ehrlichia caffeensis  Ehrlichia phagocytophila

EHRLICHIA SENNETSU  Endemic in JAPAN 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

EHRLICHIA PHAGOCYTOPHILA  Causes human GRANULOCYTIC EHRLICHIOSIS  Transmitted by IXODES ticks  Deer, cattle and sheep are suspecte reservoirs  Leucopenia and thrombocytopenia observed in patients

EHRLICHIA CAFFEENSIS  Cause human MONOCYTIC EHRLICHIOSIS  Transmitted by Amblyomma ticks  Deers and rodents reservoirs  Leucopenia and thrombocytopenia increased liver enzymes  Most dangerous can cause multisystem failure and fatality

EHRLICHIOSIS  Ehrlichiosis is infection of WBC that is characterised by mulbery shaped aggregates called morulae in infected cells  These morulae are visiible after 5-7days of infection

Pathophysiology  It is not completely known  Like RICKETTSIA sps EHRLICHIA gain access to blood via bite from infected tick

 AMBLYOMMA AMERICANAM(lone star tick) E.chaffeensis  IXODES PERSUKATUS  DERMACENTOR VARIABILIS (dog tick wood tick)

 The major antigen determinants 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

LIFE CYCLE

Mortality and morbidity  Great majority 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

 Sex: male:female = 4:1  Age: occurs at all ages but more common in young adults  Clinical manifestations usually begin in 5-14 days after tick bite

Clinical features Rash and pedal edema

 Patients with Ehrlichiosis usually 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

Cont…  Some patients develop heptomegaly  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

Distribution  Ehrlichiosis occurs worldwide and 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

Lab diagnosis  Diagnosis rests on 1)single elevated IgG IFA antibody titre 2)demonstration of incr. in acute and convalescent IFA ehrlichia titre  Difficult to culture  Detection with PCR

 Blood smear for cytoplasmic 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

Treatment  Doxycyclin  Chloramphenicol  Rifampacin  fluoroquinolones

Prevention