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Flashcards in Zoonoses Deck (119):
1

Q fever tx

Treat with doxycycline +/- surgery for endocarditis

2

Congo-Crimean Hemorrhagic Fever 

sx

animals 

location

– fever, hemorrhages

– tick, reservoir rodents

– Asia, Africa

3

Leptospirosis: Management

Doxycycline or penicillin for 1 week

• Prophylactic doxycycline 200mg weeklyi s effective in data from military clinical trials

3

Rickettsial infections

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4

Guillain-Barr’ is due to cross reaction between

 capsular oligosccharides and glycosphingolipids on nerve surface (autoimmune disease)

5

Yersinia pestis

• Vector

Xenophylla cheopis, the Rat Flea, is the main

vector; related fleas of rodents are secondary vectors

5

Ixodes sp.: Life cycle

Eggs hatch to larvae (spring to summer)

Larvae require a vertebrate blood meal to develop into nymphs (early fall)

• Nymphs become dormant in winter; require another blood meal before they can become adults (spring to summer: most infectious stage)

• Adults mate and then lay eggs (summer to fall)

• Eggs remain dormant over the winter

6

Lassa fever characteristics 

Arenaviruses

most common febrile illness in Sierra Leone

– African bush rat ( Mastomys natalensis )

– Transmission from urine from rats and patient body fluids ( nosocomially)

6

Flaviviruses

• Pathogenesis

– infect macrophages

– cell damage by cell mediators – tissue destruction by T- cell

– shock syndrome;

• virus-antibody complex enters monocytes via Fc rec

• antibody enhances infection

• generally increased production of cytokines

• severe illness, shock, hemorrhages

7

Campylobater jejuni

• Diagnosis:

Presence of “S” shaped bacteria in stool

• Detection of Campylobacter antigens in stool is more sensitive and specific for diagnosis

8

Campylobater jejuni

• sources 

Worldwide round the year infections

• Poultry is the common source, ingestion of contaminated food, water and unpasteurized milk may cause diarrhea

9

Anthrax in what animals 

Native to hoofed domestic herbivorous animals: cattle, horses, etc.

9

Brucellosis : pathogenesis

• Once skin or mucous membranes are penetrated by organisms they are carried to lymphatics by PMNs

• Cells multiply within macrophages

• Humoral response is ineffective; T-cell response required.

• Failure of T-cell control results in granulomatous inflammation with bacterial multiplication within the RES

• Waves of bacteria are released into the circulation from these sites resulting in recurrent bacteremia.

9

Flaviviruses characteristics 

• Genome:ss+ polarity, RNA

• Epidemiology:

– Arbovirus (except Hepatitis C )

– All flaviviruses serologically related- cross reacting antibodies

10

Tularemia found in 

Rabbits, beavers, deer (can be found in cats and dogs)

dog tick (Dermacentor variabilis), wood tick (Dermacentor andersoni), lone star tick (Amblyomma americanum), deer flies (Chrysops spp.)

 

10

Anaplasmosis sx

>95%: fever, myalgia, headache; 75%: renal dysfunction;

• Rarely: pancarditis, myocarditis, abdominal pain, renal failure, ARDS....

10

Filoviruses type of fever

MHF (Marburg Hemorrhagic Fever)

11

Pasteurella multocida:Epidemiology

Normal respiratory biota of many lower animals,

including cats and dogs.

• Human is infected by bite ( dog commonly) or scratch

13

Faliciparum zoonotic source 

Birds (Chickens, Ducks)

14

Yersinia pestis infection in flea vector

• Flea acquires Y. pestis when it takes a blood meal from an infected rodent host.

• Organism multiplies in proventriculus of the flea, eventually blocking the flea’s GI tract.

• Starving flea regurgitates infectious material when attempting to take another blood meal.

• Flea eventually dies of the infection

14

Tularemia - Diagnosis

history

Direct fluorescent antibody on appropriate clinical material is sufficient

15

Cat-scratch disease

 

_ Papule/pustule 3 - 10 days post cat-scratch, lick or bite.

– Fever and with regional lymphadenopathy (head, neck, axilla)

– Most cases recover completely & spontaneously

15

Q fever ( “Q” for “Query”) caused by

Caused by Coxiella burnetti

16

Rocky Mountain Spotted Fever carried by

– Dermacentor andersonii Wood Tick Western States

– Dermacentor variabilis Dog Tick Eastern States

– Ambylomma americanum Lone Star Tick Southwest

17

Diagnosis Anthrax

PCR

bx

culture 

stain 

17

Tularemia: Pathogenesis entry

through inhalation, ingestion, or injection

Bacteremic spread

– seeds RES > granulomatous inflammation>Ulcerated lesion develops at injection site

18

Leptospirosis: pathogenesis

 Can get through intact skin/mucous membranes

• Prolonged immersion in contaminated waters e.g. from falling into river waters

18

Lyme Disease organism

 (B. burgdorferi) has same range as

Ixodes sp. ticks

18

Rickettsial infections features 

• Primary infection in human vascular epithelium with capillary leak syndromes; adrenal glands also affected

• Common Clinical Manifestations

– sustained high fever

– severe retro-orbital headache

– Rash (distribution and extent differs with different species)

19

Bunyaviruses 

General characteristics 

Genome:ss-RNA,3segments;S,M,L

20

Leptospirosis hosts 

 Rodent hosts esp. Rattus norvegicus

• L. ictero-haemorrhagiae is a classical parasite of rats, L. canicola of dogs, L. hebdomadis of cattle, L. pomona of pigs

21

what inhibits certain Gram-positive bacteria in maconkey agar

crystal violet 

23

Anthrax: Clinical manifestations

Cutaneous: most common in humans- non lethal

Septicemic- high mortality 

Pulmonary: highest mortality in humans; rare under natural circumstances: “Wool- Sorter’s Disease.”

24

Yersinia pestis animals 

rodents

24

Filoviruses sx reservoir, location

– fever, rash, hemorrhage, probably disseminated intravascular coagulation

– no known reservoirs or vector

– first appeared in Marburg, Germany, 1967; lab infection from Ugandan monkeys

25

Virulence Factors: B. anthracis

• Lethal Factor

– tissue necrosis

• Edema Factor

– Causes infiltration and tissue swelling: enhance distribution of Lethal Factor

• Protective Antigen

– Probably the same substance as the Edema Factor with additional effect

26

Summary of Hemorrhagic Fever Viruses

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27

Congo crimean fever characteristics 

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28

Diseases from the most common

human Bartonella spp.

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29

Arenaviruses characteristics 

Genome: ss - RNA, 2 segments( smaller is

ambisense )

– host ribosomes in the virus particle, no function

• Epidemiology:

– reservoir in rats of many species

– spreads through rat feces and urine – mortality ranges from 10 - 50%

30

Bacillary Angiomatosis seen in who

HIV 

31

P. multocida: clinical Manifestations

 infection at site of inoculation e.g. bite

• Associated cellulitis

• Systemic infection is uncommon but can be quite severe

31

Leptospirosis: Clinical Features

Initial blood stream invasion with localization in kidneys, liver, meninges and brain

• Incubation period is 1-2 weeks with 4 syndromes:

Bacteremic: flu-like, diarrhoea and vomiting; conjunctival congestion

Meningitic: like viral meningitis

Icteric: fever, hemorrhage, hepatic and renal impairment

Pulmonary:Adult Respiratory Distress Syndro

32

Tularemia: Francisella tularensis characteristics 

Gram negative short rods

– Facultative, not spore forming

– Nutritionally fastidious: will not grow on blood or other common media; requires supplemental compounds

– Grown with Cysteine-Glucose Blood Agar (Aerobic)

– Slow growing: Requires 2 to 10 days for visible growth

32

Viral Hemorrhagic Fevers (VHFs) 

viruses 

Arena-, Bunya-, Flavi-, and Filoviridae

33

Smallpox zoonotic source 

cattle

33

Bunyaviruses reservoirs 

reservoir in mice, rats and ticks

34

Leptospirosis shed in

urine but infection is asymptomatic in animal host

34

VHF-Lassa Fever tx

Ribavirin

35

Brucellosis which one is the most infectious 

B.melitensis

36

C. burnetti shows phase variation

Infected source isolates – phase I, highly infectious; phase II within in-vitro culture; not infectious

38

Pasteurella multocida animal

cats, dogs, horses

40

Plague: Diagnosis/CDC

pre-treatment

 Lymph node aspirate: An affected bubo should contain numerous organisms that can be evaluated microscopically and by culture.

Blood cultures: Organisms may be seen in blood smears if the patient is septicemic.

• Sputum: Culture is possible from sputum of very ill pneumonic patients; however, blood is usually culture-positive at this time as well.

• Bronchial/tracheal washing may be taken from suspected pneumonic plague patients

• In cases where live organisms are unculturable, lymphoid, spleen, lung, liver tissue, bone marrow samples useful for direct detection methods such as direct fluorescent antibody (DFA) or PCR.

41

B. burgdorferi within the tick vector

Borellia sp. cells adhere to epithelial cells of tick’s midgut and remain there indefinitely in a quasi- dormant state

41

Lyme Stages: analogous to Syphilis

• Primary stage:

– ECM (Erythema Chronicum Migrans/ the target

lesion occurs in 40 - 50% of cases

• Secondary stage:

– Secondary annular skin lesions (Exanthem)

– CNS, cardiovascular, ophthalmic and musculoskeletal manifestations

• Tertiary stage:

– ACA (Acrodermatitis Chronicum Atrophicans)

– Diverse CNS symptoms, Arthritis, Cardiomyopathy

41

Bunyaviruses pathogenesis 

plasma and RBCs leak through vascular epithelium

43

CCR-5 Mutation

Persons having one copy (heterozygous) of the gene have increased resistance to HIV

• Persons having two copies (Homozygous) of the gene may be immune to HIV

• This mutation has been traced back to Western Europe in the late 14th Century: The time and Place of the Black Death!

45

Brucella spp animals

goats, cattle, swine, dogs

46

Bartonella (formerly known as Rochalimaea) characteristics 

• Gram-negative bacteria

• Facultative intracellular pathogens

 

47

B. melitensis animal and location

goats, sheep, camels [ Europe, Asia, Middle East, South & Central America]

48

Lyme Disease: tx

• Doxycycline or Amoxicillin for early disease

• Ceftriaxone or Cefotaxime for late disease with

prolonged therapy.

50

Brucella characteristics 

Gram negative short rods

• Non-motile

• Nutritionally fastidious

– Facultative Intracellular Parasites

– Require complex artificial media in-vitro

– Slow growing (up to 10 days on Blood agar)

51

Leptospirosis: Diagnosis

 PMNs rise, liver enzymes rise, CK rise ; platelets fall

• CSF shows a “viral pattern”

• Isolation from blood/ urine- special media & prolonged incubation

• Serology

• PCR

52

Scrub Typhus sx

Onset is sudden headache, fever, malaise, weakness and cough

• Maculo-papular rash about 5th – 7th day trunk, face, limbs including palms and soles with generalised painless lymphadenopathy

• Severe cases are prostrate with pneumonia, confusion ; cardiac, renal failure; hemorrhage and death

53

Rocky Mountain Spotted Fever (R. rickettsii)

• Incubationperiodcirca7days

• Rash on 3rd or 4th day looking like measles

• Skinhemorrhages

• Hepato-splenomegaly

Rash: appears on 2nd or 3rd days on wrists or ankles and spreads inward to the trunk within hours. (Centripetal Spread); extends to cover palms of the hands and soles of the feet

55

Tularemia tx

aminoglycoside

57

Yersinia pestis: Reservoirs

Sylvatic Plague: Rural reservoirs of Y. pestis still exist

in several areas of the world

– Semi-arid regions of the Southwestern U.S.A.

– Southeast Asia & Grasslands of Central Asia (the

original homeland of Y. pestis)

• Not found (in significant numbers) in: Western Europe, Africa or Australia

58

Korean Hemorrhagic Fever

characteristics 

– Hemorrhagic Fever with Renal Syndrome

– mice, rats

– far east, Scandinavia, E. Europe,

– severe pulmonary syndrome in SW US (Sin Nombre)

58

Filoviruses pathogeneis 

– tissue necrosis in parenchymal cells of liver, spleen, lungs and lymph nodes

– edema and hypovolemic shock

– BCX4430, small mol. Nucleoside analogue protected monkeys from Marburg virus and MERS-Cov

59

Lyme Disease: Diagnosis

Diagnosis:

• B. burgdorferi in blood smear during early stage only

• Serology for later stage is unreliable: ELISA, IFA

60

How does isoxazole stop filoviruses 

blocks protein NPC1 which is needed for replication 

61

Rickettsia spp. characteristics 

 gram-negative short bacillary forms

• They do not stain well with Gram’s but can be seen with Giemsa staining 

intracell organisms 

63

Plague: 

Incubation

- Bubonic form is 4 to 7 days

- Pneumonic form is 18 to 36 hours

64

Venezuelan hemorrhagic fever (Guanaritovirus)

Characteristics 

– fever, headache, sore throat, pharyngitis, loss of appetite, nausea, vomiting, seizures and nose and gum bleeding. 

– reservoir in cane rats ( Zygodontomys brevicauda ) and cotton rats ( Sigmodon alstoni )

– mortality 30 - 40%

– no vaccines

– rodent control

66

Yersinia pestis in what animals 

Voles, Rats, Ground

Hogs, Rock Squirrels

68

Francisella tularensis animals

rabbits

69

Measles zoonotic source 

Cattle (Rinderpest)

70

Yellow Fever characteristics location, animal

 

Yellow Fever virus is a Flavivirus

Reservoir – monkeys; transmission from mosquitoes

Africa, South and Central America

72

Anthrax is endemic in

sub-Saharan Africa, Asia, South and Central America, Southern and Eastern Europe

73

Dengue fever- 4(5?) location

– India, SE Asia, Pacific, South America, and the Caribbean

75

B.suis animal and location

pigs [South Asia]

76

Tuberculosis zoonotic source 

cattle

77

Yersinia pestis: Prevention and Containment

 

• Rat control

• Avoid handling, skinning wild animals in endemic areas

• 48h isolation on Rx; gowns, gloves, masks...

• Post-exposureprophylaxiswithcaseofpneumonic infection is doxycycline 100mg or ciprofloxacin 500mg bd for 1 week

• Inactivated vaccine does not work against pneumonic plague

78

Filoviruses: Ebola disease( Ebolavirus ) characteristics 

 

– sudden febrile illness, vascular collapse, internal

bleeding, death

– Incubation period: 2-21 days

– Sudan and Zaire (Democratic Republic of the Congo) ; no known vector or reservoir ? bats/primates

– 1976 first epidemic, many epidemics

– 90% mortality

79

Cutaneous Anthrax : Pathogenesis:

 Begins at site of 1° infection as a papule; progresses through a vesicular stage to a depressed black necrotic ulcer (eschar)

 Edema, redness, and/or necrosis without ulceration may occur

 Form most commonly encountered in naturally occurring cases

 Incubation period: 1–12 days

81

Pasteurella multocida characteristics

Gram negative short rods/short bacilli

• Facultative;fermentscarbohydrates

• Oxidasepositive

• Grows readily on enriched media like Blood Agar, but not on media selective for Gram negatives (MacConkeys)

83

Brucellosis: Acute Infection

Incubation time: 7-21 days 

Onset with drenching sweat with high fever (up to 40°C.); then a swinging fever, rigors, lethargy, headache, musculo-skeletal pain; scrotal pain

Occasionally delirium, abdominal pain, constipation

• Lymphadenopathy & splenomegaly

84

Ehrlichiosis/Anaplasmosis sx

 

• Symptoms include fever and GI abnormalities; severe cases progress through cough, diarrhea and lymphadenopathy up to respiratory insufficiency, renal insufficiency and CNS abnormalities.

85

HEMORRHAGIC FEVERS flow 

A image thumb
88

How is anthrax transmitted person to person 

cutaneous anthrax 

89

Acute phase of plague 

- Bubonic plague: swollen, painful inguinal lymph nodes; increasing fever, pooling of blood and microhemorrhages in face and extremities.

- Pneumonic: violent and fulminating bacterial pneumonia; nearly always fatal.

90

Leptospira interrogans characteristics 

• Tight spiral. 0.15 thick x 5 to 15 long

• Sensitive to heat, drying and most chemicals

• Survives well ( 1 to 2 weeks) in slightly alkaline ground water or soil, but does not multiply.

91

Coxiella burnetti characteristics 

• Obligate intracellular parasite

• Can survive in extracellular environment

• Cattle, sheep, goats are important reservoirs

• Transmission by inhalation of aerosolized particles

 

NO VECTOR!!

93

transmission of Bartonella (formerly known as Rochalimaea)

 

• Transmission vectors include ticks, fleas, sandflies, mosquitoes

94

Campylobater jejuni characteristics 

Thin, curved gram negative rods

• Culturing requires Low Oxygen tension and higher incubation temperature ( 42oC)

95

Brucellosis carried to lymphatics by

PMNs

96

Tularemia: Clinical Presentation

Syndromes depend on site of infection:

– Ulcero-glandular (from injection: lowest mortality) – Typhoidal (resulting from ingestion)

– Pneumonia (from inhalation: highest mortality)

97

CSF in Neuro-leptospirosis.

Slightlyormoderatelyincreasedprotein levels in CSF in 50% of cases.

Moderately increased numbers of leucocytes with prevalence of neutrophils in 50% of cases (initially) but in following days monocytes prevalent.

Glucose levels normal in 80%..

So can look like listeria or viral meningitis

98

Pertussis zoonotic source 

pigs, dogs 

99

Inhilation Anthrax: clinical features

“Flu-like” illness

Meningitis in 50% of patients

100

Rocky Mountain Spotted Fever reservoir

– Dogs

– Wild Rodents

– The tick itself (Trans-ovarial maintenance)

101

Anaplasmosis transmitted by

tick

102

Scrub Typhus transmitted by

mites

103

Zoonoses due to Campylobacter 

A image thumb
105

Yersinia pestis : Pathogenesis

Organism reaches lymph node where:

• Higher temperature induces formation of virulence factors.

• Rapid multiplication.

• Infected lymph node swells and becomes painful: a Bubo

• Progresses to bacteremia which seeds liver, spleen lungs and sometimes meninges

106

Brucella transmission

Direct occupational contact: Butchers, Veterinarians. Access through skin breaks, mucus membranes, aerosols, splashes. Ingestion of infectious dairy products. Organism is killed by pasteurization.

107

B. abortus- animal and location

cattle [Africa, Asia, South America]

108

Ehrlichiosis/Anaplasmosis

• E. canis & E. chafeensis: Human Monocytic Ehrlichiosis; transmitted by

Disease seems to be transmitted by the Brown Dog Tick in the US (?reservoir ?vector) ; often first misdiagnosed as Rocky Mountain Spotted Fever.

109

Brucellosis: Diagnosis

• Isolation from blood cultures; positive in 75% of

cases with B. melitensis and 50% with B. abortus

• Bonemarrowmaybeusefulinmorechronicstate

• CSF in neuro-infection : 30% culture positive

• Risk to laboratory staff from culture

• Serology

110

Q fever: clinical features

 

• Fever, headache, chills; 20% rash; pneumonia, hepatitis

• Osteomyelitis,encephalitis,endocarditisin chronic cases

• Diagnosis is serological; phase I and II, IgM peak at 4-6 weeks

111

Brucellosis which one forms abscess 

B. suis 

112

Brucellosis: Chronic infection signs 

Prolonged cases show marked weight loss

• Few other physical findings or signs: sometimes glandular or hepatic symptoms

• Sacro-ileitis

• Depression

113

Scrub Typhus

• Caused by

Rickettsia –like organism; Orientia

tsutsugamushi

114

Brucella reservoir

Infected animals excrete organisms for prolonged periods in milk, animal urine, feces, vaginal discharge and uterine products.

115

Influenza zoonotic source 

Pigs, Ducks

116

Bacillus anthracis characteristics 

Anthrax 

large, box-car, gram-positive rod; aerobic and spore forming

117

Filoviruses characteristics 

• Genome: ss - RNA, long filamentous virus

• Epidemiology:

– no known reservoir

– mortality ranges from 20 - 90% – confined to Africa (?)

118

Zoonotic Gram-negative bacteria

Brucella

Yersinia pestis

Francisella tularensis

Pasteurella multocida

119

Plague: Yersinia pestis characteristics 

• Gram negative short rods/bacilli

• Member of the Enterobacteriaceae:

– Gram negative non-spore forming rod

– Oxidase negative

– Facultative

– Glucose fermenter

• Grows readily in standard media

• Rich polysaccharide capsule present in virulent strains