Rickettsiaceae

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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

    1. 1. RICKETTSIACEAE Dr.T.V.Rao MD Dr.T.V.Rao MD 1
    2. 2. With Tribute to Howard Taylor • Howard Taylor Ricketts, 1871- 1910. Ricketts identified the causative agent of Rocky Mountain spotted fever. Dr.T.V.Rao MD 2
    3. 3. Rickettsiae - Discovery • The name Rickettsiae was first used by the Brazilian Henrique da Rocha-Lima who identified the agent of epidemic typhus in infected body lice, in honor of Dr. Howard Taylor Ricketts who discovered the aetiological agent of Rocky Mountain Spotted fever in 1909 and established the role of ticks in its transmission. Dr.T.V.Rao MD 3
    4. 4. Several Species - RICKETTSIACEAE • Micro-organisms in the genera rickettsiae, orientiae, bartonella, ehrlichia and coxiella are obligatory intracellular, Gram negative bacteria. They are known to cause febrile illness in both humans and in animals. With the exception of coxiella, they are transmitted between vertebrate hosts by haematophagus arthropods. Dr.T.V.Rao MD 4
    5. 5. RICKETTSIAE • Rickettsia are obligate intracellular gram negative parasites. • Most are zoonosis spread to humans by arthropods. (except Q fever). Dr.T.V.Rao MD 5
    6. 6. General introduction • Gram-negative, obligate intracellular coccobacilli bacteria that infect mammals and arthropods • Rickettsia are transmitted in the arthropods, which serves as both vector and reservoir • Both DNA and RNA • Is sensitive to antibiotic. Dr.T.V.Rao MD 6
    7. 7. 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 7
    8. 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 8
    9. 9. Rickettsia are • Rickettsia replicate within the cytoplasm of endothelial cells and smooth muscle cells of capillaries, arterioles and small arteries causing necrotizing vasculitis. • Most are febrile infections with a characteristic rash. • An ESCHAR, a black ulcerated lesion may develop at the site of inoculation Dr.T.V.Rao MD 9
    10. 10. Five genera in this class cause human diseases: Rickettsia Bartonella Coxiella (does NOT cause skin rash) Ehrlichia Orientia Dr.T.V.Rao MD 10
    11. 11. Genera •1.Rikettsia, •2.Orientia •3.Ehrcichia Dr.T.V.Rao MD 11
    12. 12. 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 12
    13. 13. The Others • Q Fever • – Coxiella burnetii • • Ehrlichiosis • – Ehrlichia canis • – Ehrlichia equi • – Ehrlichia chafeensis • – Several others now identified Dr.T.V.Rao MD 13
    14. 14. 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 14
    15. 15. Epidemic typhus and trench fever • The human body louse is the vector for both epidemic typhus and trench fever, caused by Rickettsia prowazekii and Bartonella quintanta, respectively. The illness is acquired through inhalation or inoculation of infectious louse feces into the skin or conjunctiva. Outbreaks occur in communities where body louse infestations are frequent, especially during the colder months. Dr.T.V.Rao MD 15
    16. 16. 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 16
    17. 17. 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 motile Non capsulate not stained easily Giemsa and Gimenez staining methods. Dr.T.V.Rao MD 17
    18. 18. DISEASES RICKETTSI AL AGENT INSECT VECTOR MAMMALIAN RESERVOIR TYPHUS GROUP a) Epidemic typhus R. prowazekii Louse Human b) Murine typhus (Endemic typhus) R. typhi Flea Rodents c) Scrub typhus) R. tsutsugamush i Mite Rodents Dr.T.V.Rao MD 18
    19. 19. DISEASES RICKETTSI AL AGENT INSECT VECTOR MAMMALIA N RESERVOIR SPOTTED FEVER GROUP a) Indian tick typhus R. conorii Tick Rodent, Dog b) Rocky mountain spotted fever R. rickettsii Tick Rodents, Dogs c) Rickettsial pox R. akari Mite Mice Dr.T.V.Rao MD 19
    20. 20. DISEASES RICKETTSI AL AGENT INSECT VECTOR MAMMALIA N RESERVOIR OTHERS a) Q fever C. burnetti Nil Cattle, sheep,goats b) Trench fever Rochalimaea quintana Louse Human Dr.T.V.Rao MD 20
    21. 21. Typhus Fever Dr.T.V.Rao MD 21
    22. 22. Typhus Fever group • 1. Epidemic Typhus •2. Recrudescent typhus ( Brill Zinsser’ disease ) •3. Endemic typhus Dr.T.V.Rao MD 22
    23. 23. EPIDEMIC TYPHUS (LOUSEBORNE TYPHUS) •Etiology: R. prowazekii •severe systemic infection & prostration more fatal •Brill-Zinsser Disease  recrudescent disease Dr.T.V.Rao MD 23
    24. 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 IIDr.T.V.Rao MD 24
    25. 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 25
    26. 26. Dr.T.V.Rao MD 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 26
    27. 27. Dr.T.V.Rao MD 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. 27
    28. 28. 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 28
    29. 29. Epidemic Typhus Also called as Louse borne Typhus Classical Typhus Russia Eastern Europe Devastating Epidemics in wars Napoleons retreat Russia 3 million deaths 1917 – 1921 India - Kashmir Dr.T.V.Rao MD 29
    30. 30. R. Prowazekii Louse Human Human Louse Epidemic typhus Dr.T.V.Rao MD 30
    31. 31. R. Typhi Rodent Flea Rat Tick Flea Human Rodent Murine typhus (much milder than epidemic typhus)Dr.T.V.Rao MD 31
    32. 32. Lesions in Epidemic Typhus Dr.T.V.Rao MD 32
    33. 33. 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 33
    34. 34. Pediculus humanus corporis is the Vector Dr.T.V.Rao MD 34
    35. 35. Dr.T.V.Rao MD 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 35
    36. 36. 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 ( Called as Brill Zinser Disease.) Dr.T.V.Rao MD 36
    37. 37. Dr.T.V.Rao MD 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 37
    38. 38. 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 38
    39. 39. Pattern of Temperature chart in Typhus Fever Dr.T.V.Rao MD 39
    40. 40. 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 40
    41. 41. 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 - china T.V.Rao MD Dr.T.V.Rao MD 41
    42. 42. Basis of Diagnostic Tests in Rickettsial Tests • Clinical features and an epidemiologic history compatible with a rickettsial disease. • The development of specific convalescent- phase antibodies reactive with a given pathogen or antigenic group, demonstrated most commonly by an indirect Immunoflorescent antibody test (IFA). A rise in phase 2 antibodies in acute Q fever and phase 1 antibodies in chronic Q fever. Dr.T.V.Rao MD 42
    43. 43. Other Diagnostic Methods • A positive polymerase chain reaction test. • Specific immunohistological detection of the Rickettsial agent. • Isolation of a Rickettsial agent. Ascertaining the likely place and the nature of the exposure is particularly helpful for accurate diagnostic testing. Dr.T.V.Rao MD 43
    44. 44. INVESTIGATIONS • PCR – Amplification of O tsutsugamushi DNA from the blood of febrile patients. SEROLOGICAL TESTS such as • Indirect Flourescent antibody test (IFA) test ( Titer ≥ 1: 200 ), • the Complement Fixation Test. • The Weil Felix Test • Scrub IgM ELISA Test: Highly specific test Dr.T.V.Rao MD 44
    45. 45. 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 45
    46. 46. Dr.T.V.Rao MD Treatment • Chloramphenicol • Tetracycline –Doxycycline 200mg • Response within 48 hrs. usually • Vaccine –Developed after World War II – Not commercially available 46
    47. 47. Spotted Fever Group • Rickets 1906 • Rickettsia of this group, multiplies in Nucleus and Cytoplasm • Ticks transmit Dr.T.V.Rao MD 47
    48. 48. Transmission • Typhus, spotted fever and trench fever are transmitted via arthropod vectors; • Q fever is acquired via inhalation or ingestion of contaminated milk or food. Dr.T.V.Rao MD 48
    49. 49. Tick Typhus • R.rickettsii Rocky mountain spotted fever • R.siberica • R.conori • R.australis. Ticks transmits bite- Trans ovarian spread T.V.Rao MD Dr.T.V.Rao MD 49
    50. 50. Ticks acts as vectors and reservoirs of Infection Dr.T.V.Rao MD 50
    51. 51. Dr.T.V.Rao MD 51
    52. 52. Rocky Mountain spotted fever Dr.T.V.Rao MD 52
    53. 53. Rocky mountain spotted fever Dr.T.V.Rao MD 53
    54. 54. Rocky Mountain spotted fever Dr.T.V.Rao MD 54
    55. 55. Rocky Mountain spotted fever Dr.T.V.Rao MD 55
    56. 56. 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 56
    57. 57. Diagnosis and Prevention Microscopy Serological Test (Weil-Felix reaction, ELISA, IF, PCR) Breaking the infection chain ( controlling and killing the intermediate hosts and reservoir hosts) Inactivated vaccine has protective effect Chloromycetin, tetracycline are helpful for therapy, Sulphonamides are not administered (increasing the penetrating of the vessel). Dr.T.V.Rao MD 57
    58. 58. Laboratory Diagnosis • Tissue cultures • In Vero cells, • MRC – 5 cells. Dr.T.V.Rao MD 58
    59. 59. 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 59
    60. 60. 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 60
    61. 61. WEIL-FELIX TEST • Agglutination test in which sera are tested for agglutinins to the O antigens of certain non motile Proteus strains OX19, OX2 and OXK. The basis of the test is the sharing of an Alkali stable carbohydrate antigen by rickettsiae and by certain strains of Proteus. Dr.T.V.Rao MD 61
    62. 62. WEIL-FELIX TEST (contd) • Sera from Epidemic and Endemic typhus agglutinate OX19 and sometimes OX2. • In tick borne spotted fever, both OX19 and Ox2 are agglutinated. • OXK agglutinins are found only in scrub typhus. The test is negative in Rickettsial pox, Trench fever, and Q fever. Dr.T.V.Rao MD 62
    63. 63. DISEASE WEIL-FELIX OX19 OX2 OXK Epidemic typhus ++ +/- - Endemic typhus ++ - - Scrub typhus - - ++ RMSF + + - Rickettsial pox - - - Q fever - - - Trench fever ? ? ?Dr.T.V.Rao MD 63
    64. 64. 2. Indirect Immuno-Peroxidase (IIP) Control Infected 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. Immunological Assays Newer Techniques :to detect O. tsutsugamushi Dr.T.V.Rao MD 64
    65. 65. 4. Enzyme-linked Immuno-Sorbant Assay (ELISA) 1. Add antigens Ag-coated well 3. Add anti-Ab2. Add mouse serum Ag-Ab complex Optical Density (OD) Reading 4. Add enzyme- substrate mix 5.Let colorize 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. Immunological Assays Newer Techniques :to detect O. tsutsugamushi Dr.T.V.Rao MD 65
    66. 66. Prophylaxis •Control of vectors. •Destruction animal reservoirs, Dr.T.V.Rao MD 66
    67. 67. Scrub Typhus Dr.T.V.Rao MD 67
    68. 68. Scrub Typhus • Scrub typhus caused by Orientia tsutsugamushi • 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 failureDr.T.V.Rao MD 68
    69. 69. Rickettsia tsutsugamushi. • Causative agent is Rickettsia tsutsugamushi. Found in areas where they harbour the infected chiggers particularly areas of heavy scrub vegetation's. Dr.T.V.Rao MD 69
    70. 70. • RESERVOIR: Trombiculid mite which feeds on small mammals. MODE OF TRANSMISSION: By bite of infected larval mites. Infection occurs during wet season when the mites lay their eggs. It is the larva (chigger) that feeds on vertebrate hosts. TRANSMISSION CYCLE MITE------RATS AND MICE-----MITE----RATS AND MICE MAN Dr.T.V.Rao MD 70
    71. 71. SCRUB TYPHUS Etiology: Orientia tsutsugamushi • resembles Epidemic typhus except for the ESCHAR • generalized lymphadenopathy & lymphocytosis • cardiac & cerebral involvement may be severe Dr.T.V.Rao MD 71
    72. 72. Epidemiology  Source of infection--------Rat  Route of transmission-----Trombiculid mites  Susceptible population----All susceptible  Epidemic features----------Tsutsugamushi triangle Dr.T.V.Rao MD 72
    73. 73. 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. Scrub Typhus The disease occurred and threatened people throughout Asia & Australia. The range stretches from the Far-east to the Middle-east (from Japan and Korea, Southeast Asia, Pakistan, India, to Arab countries and Turkey). There are approx. 1 million cases each year world-wide, & over 1 billion people at risk. Dr.T.V.Rao MD 73
    74. 74. Dr.T.V.Rao MD 74
    75. 75. Pathogen: Orientia tsutsugamushi Rickettsial bacteria Vector: Leptotrombidium Chigger-Mite An acute febrile, rickettsial disease caused by a gram-negative, rod- shaped (cocco-bacillus) bacterium, known as Orientia (Rickettsia) tsutsugamushi. Scrub Typhus: A Rickettsial Disease 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 75
    76. 76. Scrub typhus Dr.T.V.Rao MD 76
    77. 77. Dr.T.V.Rao MD 77
    78. 78. 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 78
    79. 79. 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 79
    80. 80. Rickettsial 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 weekDr.T.V.Rao MD 80
    81. 81. QFEVER Dr.T.V.Rao MD 81
    82. 82. Coxiella burnetii and Q Fever • Coxiella burnetii, the agent of Q fever, is mainly acquired through airborne transmission (via animal- contaminated soil and dust), and less commonly through consumption of unpasteurized milk products or exposure to infected ticks. Dr.T.V.Rao MD 82
    83. 83. 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 83
    84. 84. 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 hostDr.T.V.Rao MD 84
    85. 85. Genus – Coxiella Q Fever • Etiological agent ? • Small in size called Coxiella burnetii • 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 85
    86. 86. Coxiella burnetti • Q fever • Cow and sheep • tick • High resistance abrupt onset ,fever,headache,chills, myalgia,granulomatous hepatitis chronic diaease with subacute onset ,endocarditis,hepatic dysfunction Dr.T.V.Rao MD 86
    87. 87. Q - Fever Dr.T.V.Rao MD 87
    88. 88. 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 condition Infects Monocytes and Macrophages,Dr.T.V.Rao MD 88
    89. 89. 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 89
    90. 90. Clinical features • Present with head ache, chills, Pneumonia • Endocarditis, Meningitis, Encephalitis • Can cause latent infections. Dr.T.V.Rao MD 90
    91. 91. Laboratory Diagnosis • Indirect Immunofluorescence methods • Polymerase chain reaction, • Genus specific applications in progress. • Isolation of the organism is dangerous. Dr.T.V.Rao MD 91
    92. 92. Treatment • Doxycycline is effective. • Tetracycline are highly effective • Nursing care • May need blood transfusion. Dr.T.V.Rao MD 92
    93. 93. 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 • Infections in coyotes, dogs, and goats have been documented 93 Dr.T.V.Rao MD
    94. 94. Proposed life cycle for the agent of Human Granulocytic Ehrlichiosis Dr.T.V.Rao MD 94
    95. 95. 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 95Dr.T.V.Rao MD
    96. 96. 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 96Dr.T.V.Rao MD
    97. 97. 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 97
    98. 98. Bacterial Morphology • B.bacilliform • Pleomorphic gram negative bacteria • Carries a tuft of polar flagella. Dr.T.V.Rao MD 98
    99. 99. Clinical features • Progressive Anemia, • Bacterial invasion of Erythrocytes • Carries high mortality Dr.T.V.Rao MD 99
    100. 100. 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 years T.V.Rao MD Dr.T.V.Rao MD 100
    101. 101. 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 101
    102. 102. 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 102
    103. 103. 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 103
    104. 104. Broader Approaches in Treating Rickettsial Diseases • Treatment of most Rickettsial infections include administration of the appropriate antibiotics [e.g. tetracycline's, chloramphenicol (except for anaplasmosis), azithromycin, fluoroquinolones, or rifampicin] and supportive care. Dr.T.V.Rao MD 104
    105. 105. Treating Empirically • Treatment should usually be commenced empirically (especially in anaplasmosis as antibodies appear late, and early treatment has a better cure rate), prior to disease confirmation, and the particular antimicrobial agent and length of treatment depend on the particular infection. Rapid defervasecence with disease specific antibiotics strongly suggests a Rickettsial infection. Dr.T.V.Rao MD 105
    106. 106. Dr.T.V.Rao MD Typhus as Biological Weapon • Readily available • Stable in lice feces for weeks • Aerosolized • World Health Organization – 50kg of aerosolized typhus – City of 5 million would result in • 300,000 people exposed in 30 minutes • 125,000 people sick • 8,000 deaths 106
    107. 107. • Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in the Developing World • Email • doctortvrao@gmail.com Dr.T.V.Rao MD 107

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