Rickettsiaceae
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RICKETTSIACEAE

RICKETTSIACEAE

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  • Ehrlichia chaffeensis is the most common cause of Ehrlichiosis and leads to a disease known as human monocytotropic ehrlichiosis or HME. E. ewingii has also been identified as a cause of ehrlichiosis in humans. Both bacterial pathogens of ehrlichiosis are transmitted by the lone star tick. White-tailed deer are the major host for this tick species and serve as a natural reservoir for the bacteria. Infections of ehrlichiosis in coyotes, dogs, and goats have also been documented.
  • The onset of ehrlichiosis generally occurs about 5-10 days after a tick bite. The bacteria that causes Ehrlichiosis infects leukocytes, and more specifically, E. chaffeensis prefers to infect monocytes while E. ewingii prefers to infect granulocytes. The bacteria multiply in these cells in cytoplasmic membrane-bound vacuoles called morulae, which can sometimes be identified on blood smears. The picture to the right is an example of morulae in a monoctye caused by E. chaffeensis. A rash is observed in about 33% of patients with HME. The rash varies from a petechial or maculopapular rash to diffuse erythema and generally occurs later in the disease process. A rash is rarely seen in patients with E. ewingii infections.
  • This is the lab criteria for E. chaffensis only.

Rickettsiaceae Rickettsiaceae Presentation Transcript

  • RICKETTSIACEAE Dr.T.V.Rao MD T Dr.T.V.Rao MD 1
  • Zinsser, Lice And History• In 1935, Harvard Medical School physician and researcher Hans Zinsser wrote the brilliant and original Rats, Lice and History in which he traced the effects of vermin-borne disease on armies, cities and populations. From his extensive research on head and body lice, Zinsser stated unequivocally that "the body and head louse carry the infection [typhus] from one human to another. Dr.T.V.Rao MD 2
  • Zinsser, Lice And History Dr.T.V.Rao MD 3
  • General Characteristics• Small obligate intracellular coccobacilli• Gram negative (poorly), better stained with Giemsa (Blue)• Have cell wall, bigger than virus but smaller than bacteria• Have DNA and RNA• Have an ATP transport system that allows them to use host ATP• Arthropod reservoirs and vectors ( e.g., ticks, mites, lice or fleas).• Sensitive to antibiotics Dr.T.V.Rao MD 4
  • Category of rickettsia• Genus Rickettsia, Coxiella ,Orientia,Ehrlichia Bartonella• Species Rickettsia prowazekii (epidemic typhus), Rickettsia typhi (endemic typhus), Rickettsia rickettsii (spotted fever), Rochalimaea quintana (trench fever), Coxiella burnetii (Q fever) Dr.T.V.Rao MD 5
  • History• 17th-19th century – Epidemics in Europe as a result of war, disaster, or in prisoners• 1909: Transmission by lice• 1917-1925: Russia – Estimated 25 million cases• End of WWII – DDT used for control – Vaccine developed Dr.T.V.Rao MD 6
  • Historical Photograph on Typhus Dr.T.V.Rao MD 7
  • Structure: of Bacteria Similar with Gram negative bacteria Cell wall: outer membrane peptidoglycan lipopolysaccharide (LPS) Microcapsule and polysaccharideTwo antigenically distinct groups: LPS: heat-stable, cross-reactive with somatic antigens of non-motile Proteus species (Weil-Felix test) Outer membrane protein: heat- unstable, species-specific Dr.T.V.Rao MD 8
  • Rickettsia• Small gram negative Bacilli• Obligate intracellular pathogens.• Parasites on - Lice, Fleas, Ticks Mites colonizes the Gut. In vertebrates colonizes Vascular endothelium and Reticuloendothelial system. Dr.T.V.Rao MD 9
  • Five genera in this class cause human diseases: Rickettsia Bartonella Coxiella (does NOT cause skin rash) Ehrlichia Orientia Dr.T.V.Rao MD 10
  • ReplicationDr.T.V.Rao MD 11
  • Five genera in this class cause human diseases: Rickettsia Bartonella Coxiella (does NOT cause skin rash) Ehrlichia Orientia Dr.T.V.Rao MD 12
  • Dr.T.V.Rao MD 13
  • Genera•1.Rikettsia,•2.Orientia•3.Ehrcichia Dr.T.V.Rao MD 14
  • Typhus Group• Murine typhus (also known as endemic• typhus and flea borne typhus)• – Rickettsia mooseri (typhi)• • Epidemic typhus (also known as Brill-• Zinsser disease and louse borne typhus)• – Rickettsia prowazekii• • Scrub typhus (or Chigger fever)• – Rickettsia tsutsugamushi Dr.T.V.Rao MD 15
  • The Others• Q Fever• – Coxiella burnetii• • Ehrlichiosis• – Ehrlichia canis• – Ehrlichia equi• – Ehrlichia chafeensis• – Several others now identified Dr.T.V.Rao MD 16
  • RICKETTSIAL INFECTIONS• Fever, headache, malaise, prostration, skin rash & Hepatosplenomegaly• Classified into groups: 1. Typhus Group – Epidemic typhus, Murine typhus, Scrub typhus 2. Spotted Fever Group – RMSF, Rickettsia pox 3. Q Fever 4. Trench fever 5. Ehrlichiosis Dr.T.V.Rao MD 17
  • Diseases Caused by the Rickettsia Disease Organism Vector ReservoirRocky Mountain R. Rickettsii Tick Tick, wild rodentsspotted feverScrub typhus R. Tsutsugamushi Laval Mite Mites, wild rodents (chiggers)Epidemic typhus R. Prowazekii Louse Humans, squirrel fleas, flying squirrelsMurine typhus R. Thphi Flea Wild rodentsQ fever Coxiella Burnetii None Cattle, sheep, goats, cats Dr.T.V.Rao MD 18
  • DISEASES RICKETTSIAL INSECT MAMMALIAN AGENT VECTOR RESERVOIR TYPHUS GROUPa) Epidemic R. prowazekii Louse Humantyphusb) Murine R. typhi Flea Rodentstyphus(Endemic typhus)c) Scrub R. Mite Rodentstyphus) tsutsugamush i Dr.T.V.Rao MD 19
  • Rickettsia Prowazekii ( Von Prowazekii ) • Humans natural vertebrate hosts• Vector - Human body louse,( Pediculus humans corporis )• Lice get infected from patients.• Life cycle – get multiplied in gut 1 week• Person – person contact.• Lice bite causes itching and scratching• Enters through respiratory tract / Conjunctivae• Incubation 5- 15 days Dr.T.V.Rao MD 20
  • Genus -Rickettsia• Two groups Typhus fevers, Spotted fever.Morphology Rickettsia pleomorphic Coco bacillary, Size 0.3 to 0.6 micron x 0.8 - 2 microns.Gram negative, non motileNon capsulate not stained easily Giemsa and Gimenez staining methods. Dr.T.V.Rao MD 21
  • Typhus Fever Dr.T.V.Rao MD 22
  • Typhus Fever group• 1. Epidemic Typhus•2. Recrudescent typhus ( Brill Zinsser’ disease )•3. Endemic typhus Dr.T.V.Rao MD 23
  • EPIDEMIC TYPHUS (LOUSEBORNE TYPHUS)• Etiology: R. prowazekii• severe systemic infection & prostration• more fatal• Brill-Zinsser Disease  recrudescent disease Dr.T.V.Rao MD 24
  • Epidemic Typhus - 1• Also known as louse borne typhus because it• is spread human-to-human via the body louse• (which dies of its infection with Rickettsia• prowazekii after about three weeks)• • This is a serious disease consisting of fever,• severe headache, myalgia, and central rash• • Untreated, the mortality ranges from 20- 40%• • Major killer in concentration camps of WW II Dr.T.V.Rao MD 25
  • Cultivation• Needs cell culture lines• Grows in the Cytoplasm• Grows at 32 to 350 c• Grows in yolk sac of developing chick embryo• Grows in mouse fibroblasts, Hela,Hep2 Dr.T.V.Rao MD 26
  • Cultivation• Rickettsia can not be grown in bacteriological media, Obligate intracellular pathogens.• In continuous cell lines, Guinea pig, Mice• Infect the endothelial cells of vascular system.• Can synthesize ATP Dr.T.V.Rao MD 27
  • Life Cycle of Rickettsia Dr.T.V.Rao MD 28
  • ReplicationDr.T.V.Rao MD 29
  • Transmission • Human body louse– Pediculus humanus corporis– Infective for 2-3 days– Infection acquired by feeding on infected person– Excrete R. prowazekii in feces at time of feeding– Lice die within 2 weeks Dr.T.V.Rao MD 30
  • Transmission• Louse feces rubbed into bite or superficial abrasions• Inhalation of feces• Sylvatic typhus – Flying squirrel – 30 human cases in eastern and central U.S. Dr.T.V.Rao MD 31
  • PATHOLOGY Multiply in endothelial cells of small blood vessels Vasculitis(skin – rashes;other organs – DIC & vascular occlusion) Swollen & necrotic Thrombosis of the vessels Dr.T.V.Rao MD 32
  • Antigenic structure• Species differ with Group specific antigens.• Sharing of antigens between Rickettsia and Proteus basis of Weil – Felix Heterophile agglutination Test.• Used Proteus strains 0X 19, OX2 OXK Dr.T.V.Rao MD 33
  • Epidemic TyphusAlso called as Louse borne Typhus Classical TyphusRussia Eastern Europe Devastating Epidemics in warsNapoleons retreatRussia 3 million deaths 1917 – 1921India - Kashmir Dr.T.V.Rao MD 34
  • R. Prowazekii Louse Human Human Louse Epidemic typhus Dr.T.V.Rao MD 35
  • R. Typhi Rodent Flea Rat Tick Flea Human Rodent Murine typhus(much milder than epidemic typhus) Dr.T.V.Rao MD 36
  • Lesions in Epidemic Typhus Dr.T.V.Rao MD 37
  • Rickettsia Prowazekii ( Von Prowazekii )• Humans - natural vertebrate hosts• Vector - Human body louse,( Pediculus humans corporis )• Lice get infected from patients.• Life cycle – get multiplied in gut 1 week• Person – person contact.• Lice bite causes itching and scratching• Enters through respiratory tract / Conjunctivae• Incubation 5- 15 days Dr.T.V.Rao MD 38
  • Pediculus humanus corporis is the Vector Dr.T.V.Rao MD 39
  • Clinical Symptoms• Incubation: 7-14 days• High fever, chills, headache, cough, severe myalgia – May lead to coma• Macular eruption – 5-6 days after onset – Initially on upper trunk, spreads to entire body • Except face, palms and soles of feet Dr.T.V.Rao MD 40
  • Clinical Features• Fever, chills• Rash on 4 th day Spread from Trunk to Limbs Not face palms, sole.• In 2 nd week may into stuporous,delirious state May reach 40 % fatality• Bacteria remain latent in Lymphoid tissue, cloudy state. Because of called as Typhus• May cause Recrudescent Typhus Dr.T.V.Rao MD 41
  • Brill-Zinsser Disease• Occurs years after primary attack – Person previously affected or lived in endemic area – Viable retained organisms reactivated – Milder symptoms • Febrile phase 7-10 days – Rash often absent – Low mortality rate Dr.T.V.Rao MD 42
  • Brill- Zinser Disease Recrudescent typhus fever• Earlier recovery from typhus fever• Latency of the organism in lymphoid tissue• Reactivation leads to recrudescence.• Even louse get infected from patients.• Clinically similar but mild. Dr.T.V.Rao MD 43
  • Pattern of Temperature chart in Typhus Fever Dr.T.V.Rao MD 44
  • Endemic Typhus R.mooseri• Also called as Murine or Flea borne typhus• From Rats -Transmitted by Rat flea• Rickettsia multiplies in Gut and shed in feces• Humans bitten by infected Rat flees.• Saliva or feces rubbed on bitten area, may lead to infection.• R.typhi R. Prowazekii similar, Biological and Immunological tests. Dr.T.V.Rao MD 45
  • Clinical features• Mild disease• Rat act as reservoir.• Vector – Rat flea -Xenopsylla – cheopsis• Rat flea bites rat• Multiplies in the gut of the rat• Fleas un affted.• Man gets infected accidentally• Mexico Kashmir - chinaT.V.Rao MD Dr.T.V.Rao MD 46
  • Experiments on Animals Neill-Mooser Reaction • Male guinea pig inoculated intra peritioneally with blood of patients, or isolates of S.typhi produce – Fever, and scrotal swelling, enlarged tests, and cannot be pushed back.-due inflammation and adhesions between layers of Tunica vagina • Test positive in R.typhi Dr.T.V.Rao MD 47
  • Treatment• Chloramphenicol• Tetracycline –Doxycycline 200mg• Response within 48 hrs. usually• Vaccine – Developed after World War II – Not commercially available Dr.T.V.Rao MD 48
  • Spotted Fever Group• Rickets 1906• Rickettsia of this group, multiplies in Nucleus and Cytoplasm• Ticks transmit Dr.T.V.Rao MD 49
  • DISEASES RICKETTSIA INSECT MAMMALIA L AGENT VECTOR N RESERVOIR SPOTTED FEVER GROUPa) Indian tick R. conorii Tick Rodent, Dogtyphusb) Rocky R. rickettsii Tick Rodents,mountain Dogsspotted feverc) Rickettsial R. akari Mite Micepox Dr.T.V.Rao MD 50
  • Tick Typhus• R.rickettsii Rock mountain spotted fever• R.siberica• R.conori• R.australis. Ticks transmits bite- Trans ovarian spreadT.V.Rao MD Dr.T.V.Rao MD 51
  • Rocky Mountain spotted fever• Ticks in North / South America• Tick type R.conori.• Rickettsial Pox Resembles like chicken pox R. akari by mite Mouse reservoir host. Dr.T.V.Rao MD 52
  • Ticks acts as vectors and reservoirs of Infection Dr.T.V.Rao MD 53
  • Dr.T.V.Rao MD 54
  • Rocky Mountain spotted fever Dr.T.V.Rao MD 55
  • Rocky mountain spotted fever Dr.T.V.Rao MD 56
  • Rocky Mountain spotted fever Dr.T.V.Rao MD 57
  • Rocky Mountain spotted fever Dr.T.V.Rao MD 58
  • Genus - Ehrlichia• Small – Gram negative , obligate intracellular pathogens,• Can infected Phagocytic cells.• Called as Glandular fever• Ehrlichia sennetsu causative agent.• Cause atypical lymphocytosis• No arthropod vector,• Eating fish infected with flukes infected by these bacteria. Dr.T.V.Rao MD 59
  • Monocytic Ehrlichiosis• Caused by Ixodid ticks, E.chaffensis.• Deer, cattle, Sheep reservoirs• Leucopenia Thrombocytopenia• Liver is involved.• Doxycycline effective in Ehrlichosis• Human granulocytic Ehrlichosis E.equi. Dr.T.V.Rao MD 60
  • Laboratory Diagnosis of Rickettsial diseases• Isolation• Serology• Isolations can be dangerous if not well protected.• R.typhi R.conori, R.akari causes tunica reaction• R.prowazeki only fever Dr.T.V.Rao MD 61
  • Diagnosis and PreventionMicroscopySerological Test (Weil-Felix reaction, ELISA, IF, PCR)Breaking the infection chain ( controlling and killing the intermediate hosts and reservoir hosts)Inactivated vaccine has protective effectChloromycetin, tetracycline are helpful for therapy, Sulphonamides are not administered (increasing the penetrating of the vessel). Dr.T.V.Rao MD 62
  • Laboratory Diagnosis• Tissue cultures• In Vero cells,• MRC – 5 cells. Dr.T.V.Rao MD 63
  • Serology Weil – Felix Test Test based on principle of Hetrophile agglutination tests• Non motile strains of Proteus are selected.• OX19,OX2,OXK• Sharing alkali stable carbohydrate antigen by some Rickettsia X certain strains of Proteus vulgaris OX19,OX2, and Proteus mirabilis OXK. Dr.T.V.Rao MD 64
  • Laboratory Diagnosis• Weil – Felix is simple to perform but of Historical importance• Other tests Complement fixation tests, Agglutination, Passive hem agglutination. PCR Dr.T.V.Rao MD 65
  • DISEASE WEIL-FELIX OX19 OX2 OXKEpidemic typhus ++ +/- -Endemic typhus ++ - -Scrub typhus - - ++RMSF + + -Rickettsial pox - - -Q fever - - -Trench fever Dr.T.V.Rao MD ? ? ? 66
  • Different Methods of Diagnosis Dr.T.V.Rao MD 67
  • Older Techniques :to detect O. tsutsugamushi1. Giemsa Staining Technique:- utilizes peritoneal scrapings of infected mice.2. Weil-Felix Proteus Agglutination Test:-is a test which relies on the fact that Rickettsia and Proteus OX strains have commonantigens.:-is a test for the presence & type of rickettsial disease based on the agglutination of X-strain Proteus vulgaris with suspected Rickettsia in a patient’s blood serum sample.:-is commonly used in hospitals & clinics:-This test is now being replaced by a complement-fixation test. Weil-Felix Proteus Agglutination Test Dr.T.V.Rao MD 68
  • Newer Techniques :to detect O. tsutsugamushiImmunological Assays 2. Indirect Immuno-Peroxidase (IIP) IIP= is a modification of IFA technique that replaces the fluorochrome with peroxidase. Slide is observed using a bright-field microscope. Staining reaction is positive when O. tsutsugamushi particles stain light brown. Control Infected Dr.T.V.Rao MD 69
  • Newer Techniques :to detect O. tsutsugamushiImmunological Assays4. Enzyme-linked Immuno-Sorbant Assay (ELISA) ELISA test is a technique for detecting & measuring antigen or antibody. :-It is one of the most reliable techniques to detect antibody against scrub typhus infection. :-Its procedure is the principal for development of recent rapid diagnostic kits. :-This technique is widely used in laboratories & hospitals. Ag-Ab complex Optical Density Ag-coated (OD) well Reading 1. Add antigens 2. Add mouse serum 3. Add anti-Ab 4. Add enzyme- 5.Let colorize Dr.T.V.Rao MD substrate mix 70
  • Prophylaxis•Control of vectors.•Destruction animal reservoirs, Dr.T.V.Rao MD 71
  • Scrub Typhus• Scrub typhus caused by• Mild to fatal• 6-18 days after bite of Mite• An Escher is formed at the site of bite• With enlargement of Lymph nodes, Interstitial pneumonitis ,lymphadenopathy,spleenomegaly Encephalitis, Respiratory failure, circulatory failure Dr.T.V.Rao MD 72
  • SCRUB TYPHUSEtiology: Orientia tsutsugamushi• resembles Epidemic typhus except for the ESCHAR• generalized lymphadenopathy & lymphocytosis• cardiac & cerebral involvement may be severe Dr.T.V.Rao MD 73
  • Epidemiology Source of infection--------Rat Route of transmission-----Trombiculid mites Susceptible population----All susceptible Epidemic features----------Tsutsugamushi triangle Dr.T.V.Rao MD 74
  • Epidemiology Adul Nymp Eg h t g Infected Human animal Larva Larva Eg Nymp Adul h g t•Natural cycle-natural focalization•Natural focus disease-zoonosis-borne diseases Dr.T.V.Rao MD 75
  • Scrub Typhus An important vector-borne disease, first described in 1899 in Japan. During World War II, this disease killed thousands of soldiers who were stationed in rural or jungle areas of the Pacific theatre.The disease occurred and threatened people throughoutAsia & Australia. The range stretches from the Far-eastto the Middle-east (from Japan and Korea, SoutheastAsia, Pakistan, India, to Arab countries and Turkey). There are approx.1 million cases each year world-wide, & over 1 billionpeople at risk. Dr.T.V.Rao MD 76
  • R. Tsutsugamushi Eggs Adult stage Nymphal stage ChiggerRats Nymphal stage Nymphal stage Human Nymphal stage Adult stage Eggs Scrub typhus Dr.T.V.Rao MD 77
  • Scrub typhus Dr.T.V.Rao MD 78
  • Scrub Typhus: A Rickettsial DiseasePathogen: Orientia tsutsugamushi Rickettsial bacteria An acute febrile, rickettsial disease caused by a gram-negative, rod- shaped (cocco-bacillus) bacterium, known as OrientiaVector: Leptotrombidium (Rickettsia) tsutsugamushi. Chigger-Mite O. tsutsugamushi is transmitted to vertebrate hosts (rodents-primary host & humans- secondary or accidental host) by the bite of larval mites (chiggers) of the genus Leptotrombidium, e. g. L. deliense, L. dimphalum, etc. Dr.T.V.Rao MD 79
  • Pathogenesis and pathology Invade Local Spread by Invade VascularInoculation lymph node Blood stream endotheliumPapule Enlargement General General organmaculoppular of local symptoms of hyperaemia.eschar lymph node intoxication Systemiculcer lyphadenopath Dr.T.V.Rao MD 80
  • R. Tsutsugamushi Eggs Adult stage Nymphal stage ChiggerRats Nymphal stage Nymphal stage Human Nymphal stage Adult stage Eggs Scrub typhus Dr.T.V.Rao MD 81
  • Scrub typhus Dr.T.V.Rao MD 82
  • Clinical Manifestation• Incubation period is 4~21• Sudden onset with a fever• 1st week, systemic toxic symptoms• 2nd week, get worse, complication• 3th week, convalesce Dr.T.V.Rao MD 83
  • Specific features Eschar Probability: Higher than 60%. Location: Axillary fossa, inguinal region, perianal region, scrotum, buttocks and the thigh. Appearance: an ulcer surrounded by a red areola, is often covered by a dark scab. The most specific manifestation of scrub typhus. Dr.T.V.Rao MD 84
  • Ricketisial pox• Transmitted by mites,• Similar other spotted fever• Head ache ,fever• Escher at the site of bite by mite.• Maculopapular rash, can be vesicular,• Fever lasts for 1 week Dr.T.V.Rao MD 85
  • Skin Lesion Mite Dr.T.V.Rao MD 86
  • Q Fever• Occurs in veterinarians, ranchers, and animal researchers who are in contact with infected placenta from sheep, cattle, or goats (no arthropod vector for C. burnetii)• • Incubation period is 10-28 days• • Fever and headache are common; 50% will develop pneumonia after inhaling the organism; hepatitis & endocarditis are rare• • Specific serology establishes the diagnosis• • Bioterrorist threat? Dr.T.V.Rao MD 87
  • Coxiella Burnetii• Q fever(query fever )• Self-limiting flu-like syndrome with high fever (40℃)• Primary reservoirs are wild (cattle, sheep, goat etc.)• Non-cross reactive antigen with non- motile Proteus (Weil-Felix reaction negative)• Live in macrophages of vertebrate host Dr.T.V.Rao MD 88
  • Genus – Coxiella Q Fever• Etiological agent ?• Small in size called Coxiella burnetti• Ixodid tick spread the disease• Domestic live stock get infected.• Coxiella abundant in Tick feces,• Survive in dried feces, Milk too infective• Cause Human infection. Dr.T.V.Rao MD 89
  • Coxiella burnetti• Q fever abrupt onset ,fever,headache,chills,• Cow and sheep myalgia,granulomatous• tick hepatitis• High resistance chronic diaease with subacute onset ,endocarditis,hepatic dysfunction Dr.T.V.Rao MD 90
  • Q - Fever Dr.T.V.Rao MD 91
  • Q Fever• Wool hides, Meat, Milk• Enters through abrasions• System infection through Intestine, pulmonary,• All organs are involved• Can cause serious infection, Hepatitis and meningitis, May last for 2 – 3 years as chronic conditionInfects Monocytes and Macrophages, Dr.T.V.Rao MD 92
  • Q Fever Dr.T.V.Rao MD 93
  • Pasteurization of Milk Which method is better ?• Pasteurization by holders method not effective• Flash method effective.• Phase variation applicable Phase I and Phase II Dr.T.V.Rao MD 94
  • Clinical features• Present with head ache, chills, Pneumonia• Endocarditis, Meningitis, Encephalitis• Can cause latent infections. Dr.T.V.Rao MD 95
  • Q Fever Dr.T.V.Rao MD 96
  • Laboratory Diagnosis• Indirect Immunofluorescence methods• Polymerase chain reaction,• Genus specific applications in progress.• Isolation of the organism is dangerous. Dr.T.V.Rao MD 97
  • Treatment• Doxycycline is effective.• Tetracycline are highly effective• Nursing care• May need blood transfusion. Dr.T.V.Rao MD 98
  • Ehrlichiosis• Ehrlichia chaffeensis most common – Human monocytotropic ehrlichiosis (HME)• E. ewingii has also been identified• Transmitted by lone star tick (Amblyomma americanum)• White-tailed deer major host for tick species and natural reservoir for bacteria 99• Infections in coyotes, dogs, and goats have been documented
  • Proposed life cycle for the agent of Human Granulocytic Ehrlichiosis Dr.T.V.Rao MD 100
  • Ehrlichiosis Clinical Information• Onset occurs 5–10 days after tick bite• Infects leukocytes – E. chaffeensis prefers monoctyes – E. ewingii prefers granuloctyes – Morulae can be identified• Rash observed ~33% of patients with HME – Vary from petechial or maculopapular to diffuse erythema – Occurs later in disease• Rash rarely seen with E. ewingii infections 101
  • E. Chaffeensis Laboratory Criteria• Confirmed – Fourfold change in IgG by IFA in paired serum samples – Detection of DNA by PCR – Demonstration of antigen by IHC in biopsy or autopys sample – Isolation of bacteria by cell culture• Supportive – Elevated IgG or IgM by IFA, ELISA, dot-ELISA or other formats – Morulae identification by blood smear microscopic examination 102
  • Bartonella• Gram – ve bacilli/Anthropoids• B.bacilliform, B.quintana,B henselae• Bartonella bacilliform• Also called as Oroya fever,• A Medical student – Peruvian Daniel Carrion Credited for isolation. Called as Carrions Disease Dr.T.V.Rao MD 103
  • Bacterial Morphology• B.bacilliform• Pleomorphic gram negative bacteria• Carries a tuft of polar flagella. Dr.T.V.Rao MD 104
  • Clinical features• Progressive Anemia,• Bacterial invasion of Erythrocytes• Carries high mortality Dr.T.V.Rao MD 105
  • Bartonella ( Rochalimia )• Bartonella Quintana• Called as trench fever• Called as five day fever.• Grows in cell free culture media.• Chronic/Latent infections• Infection may lost > 20 yearsT.V.Rao MD Dr.T.V.Rao MD 106
  • Bartonella Henselae• Cat scratch disease (CSD)• Weil-Felix reaction negative• Infection by cats or dogs• “Parinaud” Eye-Lymph node syndrome The eye looks red, irritated, and painful, similar to conjunctivitis. Dr.T.V.Rao MD 107
  • Bartonella henselae• Also called s cat scratch disease• Caused by B.henselae• Needs lymph node biopsy• Staining sections with Warthim Starry sating• Associated in AIDS patients. Dr.T.V.Rao MD 108
  • Prevention• Use of repellents in endemic areas• • Protective clothing in endemic areas• • Careful inspection & quick removal of ticks• • Useful vaccine for RMSF is available for high risk groups such as forest rangers that work in endemic areas• • Weekly doxycycline may prevent scrub typhus infection in field workers Dr.T.V.Rao MD 109
  • • Programme Created by Dr.T.V.Rao MDfor Medical and Paramedical Students in the Developing World • Email • doctortvrao@gmail.com Dr.T.V.Rao MD 110