ANAPLASTACEAE Anaplastaceae - Features Ehrlichia chaffeensis Causes Human Monocytic Ehrlichiosis (HME) Ehrlichia ewingii Anaplasma phagocytophil um Human Human Granulocytic Granulocytic Anaplasmosis Ehrlichiosis Neorickettsia sennetsu Human Lymphocytic Ehrlichiosis Anaplastaceae - Features Ehrlichia chaffeensis Feature Ehrlichia ewingii Anaplasma phagocytophil um Features similar to Leucopenia Leucopenia Thrombocytop Thrombocytopeni HME but less enia severe a Risk factorElevated liver Immunocompromi enzymes sed patients Risk factorImmunocompro mised patients Neorickettsia sennetsu Mononucleosis like illness Atypical lymphocytosis Lymphadenop athy Anaplastaceae - Features Ehrlichia chaffeensis Ehrlichia ewingii Anaplasma phagocytophil um Transmitted by Tick (Amblyomma americanum) Tick (Amblyomma americanum) Tick (Ixodes scapularis) Reservoir White-tailed deer (rarely dogs) USA Distribution Neorickettsi a sennetsu Ingestion of fish carrying infected flukes White tailed Mice, squirrels, ? (not deer and dogs and whiteknown) tailed deer USA USA Japan and Malaysia EHRLICHIOSIS • They reside in vertebrate reservoirs and target vacuoles of hematopoietic cells • Few of them are pathogenic – Ehrlichia chaffeensis- human monocytic ehrlichiosis - - Ehrlichia ewingii - infects neutrophils and causes human granulocytic ehrlichiosis EHRLICHIOSIS - Anaplasma phagocytophilum - infects neutrophils, causes human granulocytic anaplasmosis - Neorickettsia sennetsu - infects lymphocytes & cause mononucleosis like syndrome (human lymphocytic ehrlichiosis) Clinical feature • Acute febrile disease - Headache, myalgia, arthralgia, cough, pharyngitis, lymphadenopathy, diarrhea, nausea, vomiting, abdominal pain and changes in mental status • Inclusions: reside inside phagosome, multiply to produce the following three stages of growth— elementary body, initial body, and mulberry like inclusions called Morula • Morulae in neutrophil (20–75%) in peripheral blood film examination • Treatment: doxycycline COXIELLA BURNETII (Q FEVER) • Causes ‘Q fever’ • History - For long time the causative agent was unknown, hence 'Query' or Q fever - Edward Derrick – identified Coxiella burnetii • Named after the two scientists Cox and Burnet who have contributed to its discovery COXIELLA BURNETII (Q FEVER) • • - Source of Infection Primary sources - infected cattle, sheep and goats Reservoirs - wild animals and ticks Mode of Transmission Inhalation of infected dust from soil, previously contaminated by urine and feces of diseased animals - Ingestion of contaminated milk - Transplacental, blood transfusion or through skin abrasions/mucosa COXIELLA BURNETII (Q FEVER) • Geographical Distribution - Endemic in most parts of the world except New Zealand and Antarctica - India- Rajasthan, Punjab, Haryana and Delhi - Rajasthan: overall prevalence 18.6% in humans and 24.7% in animals COXIELLA BURNETII (Q FEVER) • Pathogenesis: Escapes intracellular killing in macrophages by: - Inhibiting the final phagosome maturation step (cathepsin fusion) - Resistant to the acidic environment of phagolysosome by producing superoxide dismutase • Induces autoantibodies to cardiac and smooth muscles • Surface antigens (LPS) shows phase variation COXIELLA BURNETII (Q FEVER) • Clinical Manifestations • Acute Q fever: IP - 3–30 days - Hepatitis, interstitial pneumonia, fever, CNS involvement and pericarditis or myocarditis • Post Q fever fatigue syndrome: Profound myalgia, headache, sweating, arthralgia, muscle fasciculation • Latency: for 2–3 years • Chronic Q fever: endocarditis usually in patients underlying valvular heart disease, or immunosuppression • Fever is usually absent or of low grade COXIELLA BURNETII (Q FEVER) • • • • - Laboratory Diagnosis Pleomorphic gram-negative coccobacillus Extremely fastidious, highly infectious Isolation: must be done only in biosafety level 3 Cell cultures - monkey kidney cells, Vero cells Shell vial cell culture - human embryonic lung fibroblasts cell line, or yolk sacs (egg) or animals such as hamsters, mice or guinea pigs COXIELLA BURNETII (Q FEVER) • Antibody detection: most commonly used diagnostic tool • Indirect immunofluorescence assay (IFA) - sensitive, specific and method of choice • IgM appears in 7–10 days of infection  IgG appears after 14– 20 days of infection • Chronic infections - IgG antibodies to phase I antigens are elevated (>1:6400 titer) • Acute Q fever - antibodies to phase II antigens (IgG ≥1:200 and IgM ≥1:50) COXIELLA BURNETII (Q FEVER) • Immunodetection of C. burnetii in tissues: Immunoperoxidase staining targeting various antigens. • Molecular methods: - QpH1 plasmids - acute Q fever isolates - QpRS plasmids - strains isolated from endocarditis - Other target genes - 16S rRNA, 23S rRNA, superoxide dismutase & htpAB genes Treatment Q fever • Acute Q fever: - Doxycycline (100 mg bd 14 days) - Quinolones are also effective • Chronic Q fever: - Hydroxychloroquine is added to alkalinize the phagolysosome and to render doxycycline to act against organism COXIELLA BURNETII (Q FEVER) • Prevention • Control measures include: • Vaccine: Inactivated whole-cell vaccine (Q-Vax), for occupationally exposed workers • Good animal husbandry practices - proper disposal of animal excreta and aborted materials, isolation of aborting animals for 14 days • Pasteurization of milk by Flash method as C.burnetii survives Holder’s method of pasteurization BARTONELLA • Fastidious, facultative intracellular, slow-growing, gram-negative bacteria • Ability to invade mammalian cells and RBCs • Pathogens—B. bacilliformis, B. quintana, and B.Henselae Bartonella Diseases B.henselae Cat-scratch disease, Bacillary angiomatosis, Bacillary peliosis, Bacteremia, endocarditis Reservoir Cats, Other felines Transmission Exposure to cat – by scratch or bite Cat fleas associated with cat-to-cat transmission, but not cat-to-human transmission Bartonella B.quintana Diseases Trench fever Chronic bacteremia, endocarditis Bacillary angiomatosis B.bacilliformis Bartonellosis (Carrion's disease) Oroya fever Verruga peruana Reservoir Humans Transmission Louse (Pediculus humanus corporis) Humans Sand fly (Lutzomyia verrucarum) Bartonella henselae • Transmitted by cat scratch or bite Cat fleas - may be responsible for cat-to-cat (but not cat-to-man) transmission • Cat-scratch disease (CSD): Also rarely caused by Afipia felis and B.quintana 1. Typical CSD: More common form - Subacute regional lymphadenopathy (most common being axillary/epitrochlear lymph nodes) - Painless erythematous papule or pustule at the site of cat scratch 2. Atypical CSD: hepatitis, splenitis & retinitis Bartonella henselae • Enlarged lymph node of cat-scratch disease Bartonella henselae • Bacillary angiomatosis (epithelioid angiomatosis) - Angioproliferative disorder - Neovascular lesions involving skin and other organs - HIV and immunocompromised conditions Bartonella henselae • • • Bacillary Angiomatosis B. henselae and B.quintana Both cause skin lesions B. Henselae - Hepatosplenic lesions subcutaneous B.quintana - lytic bone lesions Bacillary peliosis: angioproliferative disorder - involving liver (peliosis hepatitis), spleen and lymph nodes • Bacteremia & endocarditis Bartonella quintana • Transmitted to humans by body louse feces (autoinoculated into skin due to scratching) • Causes - Trench fever - Chronic bacteremia - Endocarditis and - Bacillary angiomatosis Bartonella quintana • Classical trench fever: - Epidemics in the trenches of World War I - Periodic mild febrile illness lasting 4–5 days with 5-day intervals between the episodes (5 days fever) - Silent for Decades • Re-emerged trench fever: in USA - chronic bacteremia and endocarditis Bartonella bacilliformis • Transmitted by vector sandfly (Lutzomyia) • Reservoir – only humans • Biphasic disease: • Oroya fever or Carrion’s disease: initial, bacteremic, systemic illness presenting with or without anemia • Verruga peruana: late-onset manifestation - cutaneous vascular lesions Laboratory Diagnosis • Specimens - blood, lymph node or skin biopsies • Microscopy: Warthin-Starry silver nitrate staining and immunofluorescence staining • Culture: Blood agar at 37oC (except for B.bacilliformis at 30oC) in presence of 5% CO2 and incubated for 12–15 days - Sensitivity can be increased after cell lysis or freezing the sample Laboratory Diagnosis • • ntibody detection: A Indirect immunofluorescence assay (IFA) Enzyme immunoassay (EIA) PCR: Target genes - citrate synthase gene, 16S rRNA gene or heat-shock protein gene.