Francisella tularensis - Revision history

Aidan at 16:25, 8 July 2023

2023-07-08T16:25:08Z

← Older revision		Revision as of 16:25, 8 July 2023
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	***In North America, by [[Vector::Amblyomma americanum]] ticks, [[Vector::Dermacentor variabilis]] ticks, [[Vector::Dermacentor andersoni]] ticks, [[Vector::Chrysops discalis]] deer flies		***In North America, by [[Vector::Amblyomma americanum]] ticks, [[Vector::Dermacentor variabilis]] ticks, [[Vector::Dermacentor andersoni]] ticks, [[Vector::Chrysops discalis]] deer flies
	***In Europe, [[Vector::Aedes cinereus]] and [[Vector::Ochlerotatus exrucians]] mosquitoes are more important, as well as [[Vector::Chrysops relictus]] deer flies and [[Vector::Haematopota pluvialis]] horse flies		***In Europe, [[Vector::Aedes cinereus]] and [[Vector::Ochlerotatus exrucians]] mosquitoes are more important, as well as [[Vector::Chrysops relictus]] deer flies and [[Vector::Haematopota pluvialis]] horse flies
			***Requires a minimum of 24 hours of tick attachment to transmit to the host
	**Direct contact with animal products, including skinning, dressing, and eating wild game		**Direct contact with animal products, including skinning, dressing, and eating wild game
	***Viable in carcasses and dust for up to 136 days		***Viable in carcasses and dust for up to 136 days

Aidan: Text replacement - " species]]" to "]]"

2022-02-16T17:06:39Z

Text replacement - " species]]" to "]]"

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	*Zoonotic infection whose main animal reservoirs are rodents and rabbits		*Zoonotic infection whose main animal reservoirs are rodents and rabbits
	**In North America, the most important reservoirs are [[Sylvilagus ~~species~~]] (especially [[Sylvilagus nuttalii]], the cottontail rabbit) and [[Lepus ~~species~~]] lagomorphs (rabbits), and a number of rodents including voles, squirrels, muskrats (especially in Canada), and beavers		**In North America, the most important reservoirs are [[Sylvilagus]] (especially [[Sylvilagus nuttalii]], the cottontail rabbit) and [[Lepus]] lagomorphs (rabbits), and a number of rodents including voles, squirrels, muskrats (especially in Canada), and beavers
	**In Europe, the reservoirs include voles, hamsters, mice, and hares		**In Europe, the reservoirs include voles, hamsters, mice, and hares
	*Essentially worldwide Northern Hemisphere distribution, especially in the US, Japan, Russia, and Scandinavian countries		*Essentially worldwide Northern Hemisphere distribution, especially in the US, Japan, Russia, and Scandinavian countries
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	*Presumptive positive with a single titre ≥1:160 (tube agglutination) or ≥1:128 (microagglutination), but this can also be compatible with remote infection		*Presumptive positive with a single titre ≥1:160 (tube agglutination) or ≥1:128 (microagglutination), but this can also be compatible with remote infection
	*Definitive diagnosis is made with a four-fold rise in acute and convalescent serology collected 2 to 3 weeks apart, with at least one test being above the threshold for presumptive positive		*Definitive diagnosis is made with a four-fold rise in acute and convalescent serology collected 2 to 3 weeks apart, with at least one test being above the threshold for presumptive positive
	*May cross-react with [[Brucella]], [[Proteus]] OX19, [[Legionella]], and [[Yersinia]], but titres normally aren't particularly high, as well as with environmental, non-pathogenic [[Francisella ~~species~~]]		*May cross-react with [[Brucella]], [[Proteus]] OX19, [[Legionella]], and [[Yersinia]], but titres normally aren't particularly high, as well as with environmental, non-pathogenic [[Francisella]]

	=== Other ===		=== Other ===

Aidan: Text replacement - "[[Cellular shape::" to "[[Shape::"

2020-10-08T14:20:29Z

Text replacement - "[[Cellular shape::" to "[[Shape::"

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	===Microbiology===		===Microbiology===

	*A fastidious [[Stain::Gram-negative]] [[~~Cellular shape~~::coccobacillus]]		*A fastidious [[Stain::Gram-negative]] [[Shape::coccobacillus]]
	**Very small on Gram stain, giving a "pink sand" appearance		**Very small on Gram stain, giving a "pink sand" appearance
	**Do not stain well; fuchsine dye can help		**Do not stain well; fuchsine dye can help

Aidan at 14:18, 3 September 2020

2020-09-03T14:18:33Z

Show changes

Aidan at 13:43, 3 September 2020

2020-09-03T13:43:47Z

← Older revision		Revision as of 13:43, 3 September 2020
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	*A fastidious [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]]		*A fastidious [[Stain::Gram-negative]] [[Cellular shape::coccobacillus]]
			**Very small on Gram stain, giving a "pink sand" appearance
			**Do not stain well; fuchsine dye can help
			**Needs cysteine to grow, so doesn't grow well on normal media
	*Multiple subspecies, including ''tularensis'', ''holarctica'', ''novocida'', ''mediasiatica'', which are further subdivided into clades, and related species ''Francisella philomiragia'' and ''Francisella hispaniensis''		*Multiple subspecies, including ''tularensis'', ''holarctica'', ''novocida'', ''mediasiatica'', which are further subdivided into clades, and related species ''Francisella philomiragia'' and ''Francisella hispaniensis''
	*Subspecies of importance to humans include:		*Subspecies of importance to humans include:
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	*Discovered in 1911 in Tulare county, California		*Discovered in 1911 in Tulare county, California
	*Many names: deer fly fever, rabbit fever, etc...		*Many names: deer fly fever, rabbit fever, water rat trappers disease, etc...

	===Epidemiology===		===Epidemiology===

	*Zoonotic infection whose main animal reservoirs are rodents and rabbits		*Zoonotic infection whose main animal reservoirs are rodents and rabbits
	**In North America, the most important reservoirs are [[Sylvilagus species]] (especially [[Sylvilagus nuttalii]], the cottontail rabbit) and [[Lepus species]] lagomorphs (rabbits), and a number of rodents including voles, squirrels, muskrats, and beavers		**In North America, the most important reservoirs are [[Sylvilagus species]] (especially [[Sylvilagus nuttalii]], the cottontail rabbit) and [[Lepus species]] lagomorphs (rabbits), and a number of rodents including voles, squirrels, muskrats (especially in Canada), and beavers
	**In Europe, the reservoirs include voles, hamsters, mice, and hares		**In Europe, the reservoirs include voles, hamsters, mice, and hares
	*Essentially worldwide Northern Hemisphere distribution, especially in the US, Japan, Russia, and Scandinavian countries		*Essentially worldwide Northern Hemisphere distribution, especially in the US, Japan, Russia, and Scandinavian countries
			**In Canada, occurs mostly in the Prairies
	*Transmission:
			*Transmission through a number of mechanisms
	**Vector-borne		**Vector-borne
	***In North America, by [[Vector::Amblyomma americanum]] ticks, [[Vector::Dermacentor variabilis]] ticks, [[Vector::Dermacentor andersoni]] ticks, [[Vector::Chrysops discalis]] deer flies		***In North America, by [[Vector::Amblyomma americanum]] ticks, [[Vector::Dermacentor variabilis]] ticks, [[Vector::Dermacentor andersoni]] ticks, [[Vector::Chrysops discalis]] deer flies
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	***Viable in carcasses and dust for up to 136 days		***Viable in carcasses and dust for up to 136 days
	**Inhalation of aerosolized vectors (e.g. lawn-mowing), contact with contaminated water or mud, and animal bites of animals that have killed infected reservoir hosts (e.g. cats killing rodents)		**Inhalation of aerosolized vectors (e.g. lawn-mowing), contact with contaminated water or mud, and animal bites of animals that have killed infected reservoir hosts (e.g. cats killing rodents)
			**Potential for [[Bioterrorism agents\|bioterrorism]], especially with waterborne or aerosol transmission

	===Pathophysiology===		===Pathophysiology===

Aidan: /* Complications and Prognosis */

2020-09-03T10:08:52Z

Complications and Prognosis

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	*Without treatment, complications include meningitis, encephalitis, pericarditis, peritonitis, osteomyelitis, splenic rupture, and thrombophlebitis		*Without treatment, complications include meningitis, encephalitis, pericarditis, peritonitis, osteomyelitis, splenic rupture, and thrombophlebitis
	*Rarely, [[Guillain-Barré syndrome]] following ulceroglandular tularemia		*Rarely, [[Guillain-Barré syndrome]] following ulceroglandular tularemia
			*Mortality is 60% without treatment, and decreases to 2 to 4% with antibiotics

	==Diagnosis==		==Diagnosis==

Aidan: /* Typhoidal Tularemia */

2020-09-03T10:08:06Z

Typhoidal Tularemia

← Older revision		Revision as of 10:08, 3 September 2020
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	*Febrile illness without lymphadenopathy or ulcer, sometimes with diarrhea		*Febrile illness without lymphadenopathy or ulcer, sometimes with diarrhea
			*May involve [[endocarditis]]
	*Patient often has an underlying chronic disease		*Patient often has an underlying chronic disease
	*Often rapidly-progressive and fatal		*Often rapidly-progressive and fatal
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	*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work		*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work

	=== Complications and Prognosis ===		===Complications and Prognosis===

	* Suppurative lymphadenopathy is the most common complication despite antibiotics, and may require drainage		*Suppurative lymphadenopathy is the most common complication despite antibiotics, and may require drainage
	* Severe disease may cause DIC, renal failure, rhabdomyolysis, jaundice, and hepatitis		*Severe disease may cause DIC, renal failure, rhabdomyolysis, jaundice, and hepatitis
	* Without treatment, complications include meningitis, encephalitis, pericarditis, peritonitis, osteomyelitis, splenic rupture, and thrombophlebitis		*Without treatment, complications include meningitis, encephalitis, pericarditis, peritonitis, osteomyelitis, splenic rupture, and thrombophlebitis
	* Rarely, [[Guillain-Barré syndrome]] following ulceroglandular tularemia		*Rarely, [[Guillain-Barré syndrome]] following ulceroglandular tularemia

	==Diagnosis==		==Diagnosis==

Aidan: /* Clinical Manifestations */

2020-09-03T10:07:31Z

Clinical Manifestations

← Older revision		Revision as of 10:07, 3 September 2020
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	*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work		*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work

			=== Complications and Prognosis ===

			* Suppurative lymphadenopathy is the most common complication despite antibiotics, and may require drainage
			* Severe disease may cause DIC, renal failure, rhabdomyolysis, jaundice, and hepatitis
			* Without treatment, complications include meningitis, encephalitis, pericarditis, peritonitis, osteomyelitis, splenic rupture, and thrombophlebitis
			* Rarely, [[Guillain-Barré syndrome]] following ulceroglandular tularemia

	==Diagnosis==		==Diagnosis==

Aidan: /* Diagnosis */

2020-09-03T10:02:20Z

Diagnosis

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	**May have a [[Causes::relative bradycardia]] (more common in US than Europe)		**May have a [[Causes::relative bradycardia]] (more common in US than Europe)
	*These symptoms may remit and relapse, presenting as a subacute [[Causes::relapsing fever]] over weeks, with associated weight loss, deconditioning, and lymphadenopathy		*These symptoms may remit and relapse, presenting as a subacute [[Causes::relapsing fever]] over weeks, with associated weight loss, deconditioning, and lymphadenopathy
			*Bloodwork may show [[leukocytosis]] and elevated ESR, as well as occasional [[thrombocytopenia]], [[hyponatremia]], elevated liver enzymes, elevated CK, myoglobinuria, and steril pyuria

	=== Ulceroglandular Tularemia ===		===Ulceroglandular Tularemia===

	*Ulcer develops at site of inoculation with tender lymphadenopathy and systemic symptoms		*Ulcer develops at site of inoculation with tender lymphadenopathy and systemic symptoms

	=== Glandular Tularemia ===		===Glandular Tularemia===

	*Ulcer is undetectable or healed, only lymphadenopathy and systemic illness remains		*Ulcer is undetectable or healed, only lymphadenopathy and systemic illness remains

	=== Oculoglandular Tularemia ===		===Oculoglandular Tularemia===

	*Entry through the conjuctiva		*Entry through the conjuctiva
	*Rare		*Rare

	=== Pharyngeal Tularemia ===		===Pharyngeal Tularemia===

	*Entry through the oropharynx, with exudative pharyngitis/tonsillitis		*Entry through the oropharynx, with exudative pharyngitis/tonsillitis
	*May be difficult to distinguish from other forms of tularemia that also may have sore throat		*May be difficult to distinguish from other forms of tularemia that also may have sore throat

	=== Typhoidal Tularemia ===		===Typhoidal Tularemia===

	*Febrile illness without lymphadenopathy or ulcer, sometimes with diarrhea		*Febrile illness without lymphadenopathy or ulcer, sometimes with diarrhea
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	*Often rapidly-progressive and fatal		*Often rapidly-progressive and fatal

	=== Pneumonic Tularemia ===		===Pneumonic Tularemia===

	*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work		*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work
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	==Diagnosis==		==Diagnosis==

			*Diagnosis is primarily clinical, and treatment should be given while attempting to confirm with diagnostic testing
	*Culture		*Culture
			**Notify lab that tularemia is suspected before sending samples
			**Gram stain is very rarely positive
			**May be isolated from blood, pleural fluid, lymph nodes, wounds, sputum, and gastric aspirates
	**Grows slowly on standard culture media, needs cystine-rich media (e.g. chocolate agar, BHI, or cystine media)		**Grows slowly on standard culture media, needs cystine-rich media (e.g. chocolate agar, BHI, or cystine media)
	**Looks bacillary in logarithmic growth phase (small Gram-negative rod), slow-growing only on chocolate agar		**Looks bacillary in logarithmic growth phase (small Gram-negative rod), slow-growing only on chocolate agar
	*Serology ~~(EIA)~~ ~~can~~ be ~~used~~ in ~~the~~ ~~right~~ ~~context~~		*Serology is the most common test used to diagnose
			**Can use tube agglutination (used in Ontario and the US), microagglutination, hemagglutination, enzyme-linked immunosorbent assay (used in Europe), or immunochromatographic assay
	*PCR
			**IgM and IgG appear together, usually after 2 weeks and peak at 4 to 5 weeks
			**Can persist for at least 10 years
			**Presumptive positive with a single titre ≥1:160 (tube agglutination) or ≥1:128 (microagglutination), but this can also be compatible with remote infection
			**Definitive diagnosis is made with a four-fold rise in acute and convalescent serology collected 2 to 3 weeks apart, with at least one test being above the threshold for presumptive positive
			**May cross-react with [[Brucella]], [[Proteus]] OX19, [[Legionella]], and [[Yersinia]]
			*DFA and PCR are available at reference labs
			*Automated methods should not be used, due to the risk of aerosolization, and may also misindentify as [[Haemophilus]] or [[Aggregatibacter]] species

	==Management==		==Management==

Aidan at 09:22, 3 September 2020

2020-09-03T09:22:58Z

← Older revision		Revision as of 09:22, 3 September 2020
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	**Inhalation of aerosolized vectors (e.g. lawn-mowing), contact with contaminated water or mud, and animal bites of animals that have killed infected reservoir hosts (e.g. cats killing rodents)		**Inhalation of aerosolized vectors (e.g. lawn-mowing), contact with contaminated water or mud, and animal bites of animals that have killed infected reservoir hosts (e.g. cats killing rodents)

	=== Pathophysiology ===		===Pathophysiology===

	* Infectious dose depends on route, but is as low as 10 to 50 organisms when injected intradermally or inhaled (or several orders of magnitude higher if ingested)		*Infectious dose depends on route, but is as low as 10 to 50 organisms when injected intradermally or inhaled (or several orders of magnitude higher if ingested)
	* [[Toll-like receptors\|TLR4]] has less affinity for its LPS compared to other bacteria		*[[Toll-like receptors\|TLR4]] has less affinity for its LPS compared to other bacteria
	* Capsule inhibits IgM and complement C3		*Capsule inhibits IgM and complement C3
	** Capsule-deficient strains are both less immunogenic and less virulent		**Capsule-deficient strains are both less immunogenic and less virulent
	* Facultative intracellular growth		*Facultative intracellular growth
	** Can infect and persist within erythrocytes, providing protection against [[aminoglycosides]]		**Can infect and persist within erythrocytes, providing protection against [[aminoglycosides]]

	==Clinical Manifestations==		==Clinical Manifestations==
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	**May have a [[Causes::relative bradycardia]] (more common in US than Europe)		**May have a [[Causes::relative bradycardia]] (more common in US than Europe)
	*These symptoms may remit and relapse, presenting as a subacute [[Causes::relapsing fever]] over weeks, with associated weight loss, deconditioning, and lymphadenopathy		*These symptoms may remit and relapse, presenting as a subacute [[Causes::relapsing fever]] over weeks, with associated weight loss, deconditioning, and lymphadenopathy

⚫	*~~'''Ulceroglandular:''' ulcer~~ develops at site of inoculation with tender lymphadenopathy and systemic symptoms
			=== Ulceroglandular Tularemia ===
⚫	*~~'''Glandular:''' ulcer~~ is undetectable or healed, only lymphadenopathy and systemic illness remains

⚫	*~~'''Oculoglandular:''' entry~~ through the conjuctiva
		⚫	*Ulcer develops at site of inoculation with tender lymphadenopathy and systemic symptoms
⚫	*~~'''Pharyngeal:''' entry~~ through the oropharynx, with exudative pharyngitis/tonsillitis

⚫	*~~'''Typhoidal:''' febrile~~ illness without lymphadenopathy or ulcer, sometimes with diarrhea~~; patient often has an underlying chronic disease~~
			=== Glandular Tularemia ===
⚫	*~~'''Pneumonic:'''~~ direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work

		⚫	*Ulcer is undetectable or healed, only lymphadenopathy and systemic illness remains

			=== Oculoglandular Tularemia ===

		⚫	*Entry through the conjuctiva
			*Rare

			=== Pharyngeal Tularemia ===

		⚫	*Entry through the oropharynx, with exudative pharyngitis/tonsillitis
			*May be difficult to distinguish from other forms of tularemia that also may have sore throat

			=== Typhoidal Tularemia ===

		⚫	*Febrile illness without lymphadenopathy or ulcer, sometimes with diarrhea
			*Patient often has an underlying chronic disease
			*Often rapidly-progressive and fatal

			=== Pneumonic Tularemia ===

		⚫	*Acquired by direct inhalation, often from sheep shearing, landscaping, and microbiology laboratory work

	==Diagnosis==		==Diagnosis==
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	**Aminoglycosides have poor CNS penetration		**Aminoglycosides have poor CNS penetration

	== Prevention ==		==Prevention==

	=== Vaccination ===		===Vaccination===

	* Live attenuated vaccine derived from ''holarctica''		*Live attenuated vaccine derived from ''holarctica''

	=== Lab Safety ===		===Lab Safety===

	* This is a [[Biosafety risk groups\|biosafety risk group]] 3 organism		*This is a [[Biosafety risk groups\|biosafety risk group]] 3 organism
	* Should be suspected with any slowly-growing, small, and poorly-staining Gram-negative coccobacillus is isolated on chocolate agar but not blood agar		*Should be suspected with any slowly-growing, small, and poorly-staining Gram-negative coccobacillus is isolated on chocolate agar but not blood agar
	* Automated laboratory identification systems should ''not'' be used, because the risk of aerosol generation		*Automated laboratory identification systems should ''not'' be used, because the risk of aerosol generation
	* Commonly misidentified by automated methods as [[Haemophilus species\|Haemophilus]] or [[Aggregatibacter]] species		*Commonly misidentified by automated methods as [[Haemophilus species\|Haemophilus]] or [[Aggregatibacter]] species
	{{DISPLAYTITLE:''Francisella tularensis''}}		{{DISPLAYTITLE:''Francisella tularensis''}}
	[[Category:Gram-negative bacilli]]		[[Category:Gram-negative bacilli]]