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infectious > Yersinioses. Plague and Tularemia. > Flashcards

Yersinioses. Plague and Tularemia. Flashcards

1
Q

what are the CHARACTERISTICS OF YERSINIA ?

A

enterobacteriae
gram negative and rod shaped
motile except Y pests
aerobic

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2
Q

what are the different subtypes of yersinoses?

A

Y pestis
Y pseudotuberculosis
Y enterocolitica

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3
Q

what is the epidemiology of yersinosis?

A

there is a worldwide distribution of yersinosis

the reservoir - wild and domestic animals - ESP pigs

3rd commonest zoonosis in europe

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4
Q

what is the transmission of yersina ?

A

consumption of raw meat , unpasteurized milk products

contaminated water

direct / indirect contact with infected animal

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5
Q

what is the etiology of yersinosis

A

yersinia enterocolitica

yersina pseudotuberculosis

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6
Q

what is the incubation period for yesrinosis ?

A

4-6 days

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7
Q

what is the pathogenesis of yersinosis ?

A

oral route of infection

initial replication in the small intestine - invasion into the Peters patch of the distal ileum via the M cells

spread to the mesenteric lymph nodes

involvement of the liver and spleen is common

attachment to the hosts cells surface by targeting immune effector cells - alteration of host innate immunity

toxins are injected into the macrophages , neutrophils and dendritic cells - reduction of phagocytosis and inhibiting production of ROS and triggering apoptosis of macrophages

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8
Q

what are the clinical features of yersinosis ?

A

lasts 1-46 days

Y enterocolitica

inflammatory diarrhea - may be bloody in severe cases
low grade fever
vomiting
pseudo appendicitis - mesenteric lymphadenitis , particularly in the ileum with typical signs of appendicitis

children < 4y = self limiting diarrhea
- sometimes bloody

> 4yr - abdominal pain in the right iliac fossa (mimicking appendicitis)
mesenteric adeninitis and terminal ileitis

========
Y pseudotuberculosis

mostly associated with mesenteric adeninitis

present with fever and abdominal pain in all age groups

=======

both subtypes can present septicaemia - fever

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9
Q

what is the complication of yersinosis ?

A

post infectious

in patients with HLA-B27
reactive arthritis - 2-4wks

erythema nodosum

granulomatosis appendicitis

mycotic aneurysms

focal abscesses

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10
Q

how do you diagnose yersinosis ?

A

blood / csf / stool sample cultures

direct pathogen detection in culture

agglutinating or ELISA to specific o antigens

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11
Q

what is the treatment to yersinosis ?

A

spontaneous resolution
sever cases - fluoroquinilones for 2 weeks

or 3rd gen cephalosporins

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12
Q

what is the EPIDEMIOLOGY OF YERSINIA PESTIS / BUBONIC PLAGUE

A

systemic zoonosis - affecting small rodents

its in western US

reservoir - prairie dogs , squirrels , rodents

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13
Q

what’s the vector yersinia pestis?

A

vector - fleas

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14
Q

what’s the route of transmission of the black plague?

A

flea bites

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15
Q

what is the pathogenesis of yersinia pestis?

A

3 virulent plasmids are necessary :

1) classical plasmid - genres form yersinia outer protein - yops - manipulate host cell
2) larger plasmid - coding for capsule protein - counteracts phagocytosis

3) smaller plasmid - coding for
pesticin & coagulase

===

multiplication within flea & transmission to humans depend on coagulase =
temperature- dependent enzyme:

<30°C: coagulation promoting

>30°C: fibrinolysis promoting

-

flea: environmental temperature
 blood coagulation within the stomach
 coagulation mixture extends into oesophagus
 blockage of the oesophagus
 flea cannot take up any more blood
 stimulation of hunger
 next blood meal
 mixing of fresh blood with old coagulated blood
blood mixture triggers gag reflex
 injection of bacteria into new host

-
host: body temperature of 37°C causes fibrinolysis
 improves systemic dissemination
of agent

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16
Q

what is the incubation period for bubonic plague ?

A

2-6 days

17
Q

what are the clinical manifestation of bubonic plague

A

sudden onset of fever, malaise, myalgia, dizziness & increasing pain due to progressive lymphadenitis

lymphadenitis affects LN (buboes) near the fleabite-
tense, tender swelling
 mostly affecting the
inguinal , crural, axillary, cervical & submaxillary LN

 abdominal pain from mesenteric LN involvement

===========

without treatment dissemination occurs causing severe illness
 pneumonia
(secondary pneumonic plague) & meningitis

============
primary septicemic plague
: septicaemia without preceding lymphadenopathy
 increased risk for persons
older than 40y & persons with chronic conditions

=========

primary pneumonic plague
: caused by inhalation of infectious bacteria of droplets
from other persons/animals

with secondary/primary pneumonic plague

 incubation: 2 -3d

 sudden onset of fever, headache, myalgia
, weakness, vomiting,

respiratory symptoms arising after 24h: cough, dyspnea, chest pain, sputum
with haemoptysis

initially segmental pneumonitis
lobar pneumonia
bilateral lung
involvement

==========

plague pharyngitis
: consumption of contaminated meat or contact with an infected
person with pneumonic plague

 resembles tonsillitis with peritonsillar abscess & cervical lymphadenopath

18
Q

what is the prognosis of bubonic plague ////

A

with appropriate treatment before dissemination of the plague : fever resolution within 2 -5d,

buboes remain enlarged for >1w

19
Q

what are the COMPLICATION OF PRIMARY BUBONIC PLAGUE ?

A 
secondary pneumonic plague
\: consequence of
bacteraemia in 10-
15% of patients with
bubonic plague

=======

  • meningeal plague
    : >1w after onset of bubonic/septicemic plague due to suboptimal antimicrobial therapy
     fever & headache
20
Q

what is diagnosis of bubonic plague ?

A

bacterial culture from buboes aspirate, blood or sputum

=====

Microscopy with Wayson stain taken from buboes, blood, or sputum show bipolar staining of bacteria (appearance of “closed safety pin”

=========

PCR
anti- F1 antibody

21
Q

what is the treatment of bubonic plague

A

Do not delay treatment for diagnosis

First-line: IV gentamicin OR fluoroquinolones for 10–14 days

Second-line: doxycycline OR tetracycline

22
Q

what is the prevention of yersina pestis ?

A

post - exposure

antimicrobial prophylaxis : 7d with Levofloxacin & Ciprofloxaci

23
Q

what is the etiology of tularemia?

A

zoonosis Francisella tularensis

24
Q

what is the reservoir of tularemia ?

A

rabbits, hares, and rodents (e.g., voles, muskrats)

25
Q

what is the vector of tularemia ?

A

intermediate vector

Ticks (Amblyomma americanum, Dermacentor spp.)

Deer flies (Chrysops species)

Transmission without a vector is also possible via:
Inhalation of contaminated dust or aerosols (may result in pulmonary disease)
Ingestion of contaminated food or water

26
Q

epidemiology of Francisella tularensis ?

A

The bacterium is extremely infectious,
even very small amounts

can initiate disease!

27
Q

what is the transmission of Francisella tularensis ?

A

usually occurs with direct contact with infected rodents - voles, muskrats)

through intermediate vector bites 
Ticks (Amblyomma americanum, Dermacentor spp.)
Deer flies (Chrysops species)

Person-to-person transmission does NOT occur!

28
Q

what is the incubation period of tularemia ?

A

typically 3–5 days (range 1–21 days

29
Q

turalemia is also called ?

A

rabbit fever

30
Q

characteristics of turalemia ?

A

mall, aerobic, nonmotile, non-spore-forming, gram-
negative coccobacilli

2 subspecies of F. tularensis, subsp. tularensis and
subsp. holarctica
cause human tularemia

31
Q

epidemiology of F. Tularensis

A

widely distributed but is primarily a disease of the
Northern Hemisphere -> Arkansas, Kansas, Missouri, and Oklahoma
-
also present in Europe, has been reported in Bulgaria
-
peaks in late spring and summer in US

can cause illness in domestic
animals (cats and dogs)

32
Q

what are the risk groups in tularemia ?

A

hunters, wildlife
specialists, hikers, campers,
veterinarians

more common in males than
females, and higher incidence in children < 10 years of age

33
Q

what is the pathogenesis of tularemia ?

A

obligate intracellular pathogen that enters and replicates
within the cytoplasm
of various host cells (macrophages, dendritic
cells, and polymorphonuclear neutrophils)
-
within the host -> replicates locally -> then spreading to local lymphnodes
-

-> systemic spread to the liver, spleen, and lungs

-
uncontrolled replication -> cell death, substantial tissue damage,and impairment of vital organs
-
no toxin production, but it causes the failing to stimulate the host’s
innate immunity!!
-
When there is no innate immunity, bacteria can easily grow and
replicate -> triggers a systemic inflammatory reaction that
overwhelms the host defense system -> followed by cell death
-
=> extensive tissue injury
-
Histologic hallmark: Inflammatory cell infiltration and necrosis within
lymph nodes

34
Q

clinical manifestation of tularemia ?

A

Flu-like symptoms
High fever
Tender regional lymphadenopathy

======

Localized signs depending on manifestation:

usually tick bite 
Ulceroglandular tularemia (45–85%):
first a small papule appears at the site of organism entry -> then onset of fever
papule undergoes necrosis, leaving a tender ulcer with a raised border
 at the entry site of F. tularensis

painful regional lymphadenopathy
- in one or more adjacent lymph nodes
In children more commonly affected are cervical and occipital; and
inguinal adenopathy in adults

==========

Glandular tularemia (10–25%): tender regional lymphadenopathy with no skin ulcer
more common in children

============

Oculoglandular tularemia (<5%): entry of organism into the eye

fever
unilateral conjunctivitis with mucopurulent discharge photophobia,
eyelid swelling, and ulcers or pustules on the palpebral conjunctivae
tender preauricular and/or cervical lymphadenopathy

==========

Oropharyngeal tularemia (<5%):
fever
sore throat, mouth ulcers, tonsillitis, tender cervical lymphadenopathy

========

Pneumonic tularemia (< 5%): 
MOST severe form 
nonproductive paroxysmal  cough,
 pleuritic/ retrosternal  pain, dyspnea 
 lobar and multilobar infiltrates, lung abscesses, and hilar
adenopathy

exudative Pleural effusions may occur

============

Typhoidal tularemia (< 5%): hepatosplenomegaly

35
Q

what is the diagnosis of turalemia ?

A

specific hints in the anamnesis: hunters or persons in
contact with rabbits/bunnies are especially at risk!

 Serology:
IFA test: four-fold increase in F. tularensis-specific antibody titers between acute and convalescent serum samples

 Microbiological culture - on charcoal yeast extract agar -
from infected ulcer-scrapings, pharyngeal swab, sputum specimen
- Risky procedure since organism is very infectious! E.g. can also infect via
inhalation!

 PCR

36
Q

what is the treatmnet of turalemia ?

A

10-14 days with
Streptomycin or Gentamicin

 Alternatives:
Doxycycline, Fluorochinoloes or Macrolide

37
Q

what are the complication of turalemia ?

A 
Usually from delay of treatment
-
Most common: suppuration of infected lymph nodes requiring
surgical drainage(s)
-
hepatic abscesses, hepatitis
-
renal failure
38
Q

prevention of tularaemia ?

A

insect repellents and wearing of long pants, long sleeves, and
long socks can reduce the risk of tick and deerfly bites
-
If tick bites are found -> must be removed by tweezers

infectious (33 decks)

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