Leptospira: Difference between revisions
From IDWiki
Leptospira
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− | == |
+ | ==Background== |
− | === |
+ | ===Microbiology=== |
− | * Thin, flagellated [[Cellular shape::spirochete]] |
||
− | * Best viewed with darkfield microscopy |
||
− | * Species and serovars are divided into three broad categories within the genus ''Leptospira'' |
||
− | ** Pathogens: ''L. interrogans'' (multiple serovars, most common), ''L. noguchii'', ''L. borgpetersenii'', ''L. santarosai'', ''L. kirschneri'', ''L. weilii'', ''L. alexanderi'', ''L. alstonii'', ''L. meyeri'', ''L. wolffi'', and ''L. kmetyi'' |
||
− | ** Non-pathogenic saprophytes: ''L. biflexa'', ''L. wolbachii'', ''L. vanthielii'', ''L. terpstrae'', ''L. yanagawae'', and ''L. idonii'' |
||
− | ** Species of indeterminate pathogenicity: ''L. inadai'', ''L. fainei'', ''L. broomii'', and ''L. licerasiae'' |
||
− | * Within each species, there may be multiple serovars that are defined based on lipopolysaccharide (LPS) O-antigens |
||
− | ** A single species may have pathogenic and non-pathogenic serovars |
||
+ | *Thin, flagellated [[Cellular shape::spirochete]] |
||
− | === Epidemiology === |
||
+ | *Best viewed with darkfield microscopy |
||
− | * Endemic worldwide |
||
+ | *Species and serovars are divided into three broad categories within the genus ''Leptospira'' |
||
− | ** More common during rainy seasons in tropical regions and late summer to fall in temperate regions |
||
+ | **Pathogens: ''L. interrogans'' (multiple serovars, most common), ''L. noguchii'', ''L. borgpetersenii'', ''L. santarosai'', ''L. kirschneri'', ''L. weilii'', ''L. alexanderi'', ''L. alstonii'', ''L. meyeri'', ''L. wolffi'', and ''L. kmetyi'' |
||
− | ** In US, more common in Hawaii |
||
+ | **Non-pathogenic saprophytes: ''L. biflexa'', ''L. wolbachii'', ''L. vanthielii'', ''L. terpstrae'', ''L. yanagawae'', and ''L. idonii'' |
||
− | * Major reservoir is as a chronic kidney infection in animals, especially rodents |
||
+ | **Species of indeterminate pathogenicity: ''L. inadai'', ''L. fainei'', ''L. broomii'', and ''L. licerasiae'' |
||
− | ** Among livestock, may cause spontaneous abortions |
||
+ | *Within each species, there may be multiple serovars that are defined based on lipopolysaccharide (LPS) O-antigens |
||
− | * Most common risk factor is exposure to water or soil contaminated with rodent urine |
||
+ | **A single species may have pathogenic and non-pathogenic serovars |
||
− | ** Includes occupational exposures and direct contact |
||
− | ** High-risk occupations include farmers, slaughterhouse workers, pet traders, veterinarians, rodent catchers and sewer workers |
||
− | * Leptospires can survive in water or soil for months, depending on the conditions |
||
− | === |
+ | ===Epidemiology=== |
− | * Bacteria enter through cuts and abrasions, mucous membranes, conjunctivae, and inhalation |
||
− | * After entering, it disseminates hematogenously |
||
− | * Human TLR4 cannot bind leptospiral LPS |
||
− | * Virulence factors |
||
− | ** Sphingomyelinase and hemolysin |
||
− | ** Also spirochete motility |
||
− | ** Also hooked ends |
||
+ | *Endemic worldwide |
||
− | == Clinical Manifestations == |
||
+ | **More common during rainy seasons in tropical regions and late summer to fall in temperate regions |
||
− | * Spectrum of severity, from asymptomatic seroconversion (most common) to nonspecific febrile illness to severe, life-threating multiorgan failure |
||
+ | **In US, more common in Hawaii |
||
− | ** Asymptomatic disease is likely frequent, given high seroprevalence in some populations |
||
+ | *Major reservoir is as a chronic kidney infection in animals, especially rodents |
||
− | * Incubation period [[Usual incubation period::10 days]] (range [[Incubation period range::5 to 14 days]]) |
||
+ | **Among livestock, may cause spontaneous abortions |
||
− | * '''Acute febrile phase''' |
||
+ | *Most common risk factor is exposure to water or soil contaminated with rodent urine |
||
− | ** Acute phase lasts 5 to 7 days |
||
+ | **Includes occupational exposures and direct contact |
||
− | ** Starts with high fevers, headaches, chills, rigors, and myalgias |
||
+ | **High-risk occupations include farmers, slaughterhouse workers, pet traders, veterinarians, rodent catchers and sewer workers |
||
− | ** Conjunctival injection is an identifying feature |
||
+ | *Leptospires can survive in water or soil for months, depending on the conditions |
||
− | ** Muscle tenderness, especially in the calf and lumbar areas, is also characteristic |
||
+ | |||
− | ** Occasionally have a pretibial papular eruption |
||
+ | ===Pathophysiology=== |
||
− | ** Can also have lymphadenopathy, splenomegaly, and hepatomegaly |
||
+ | |||
− | ** Mild leukocytosis and neutrophilia, with thrombocytopenia and occasionally anemia |
||
+ | *Bacteria enter through cuts and abrasions, mucous membranes, conjunctivae, and inhalation |
||
− | ** Spirochetes detectable in blood and CSF, possibly urine |
||
+ | *After entering, it disseminates hematogenously |
||
− | * '''Immune phase''' |
||
+ | *Human TLR4 cannot bind leptospiral LPS |
||
− | ** Lasts 4 to 30 days |
||
+ | *Virulence factors |
||
− | ** Corresponds with the appearance of IgM antibodies |
||
+ | **Sphingomyelinase and hemolysin |
||
− | ** Spirochete is cleared from blood and CSF but detectable in other organs, including urine |
||
+ | **Also spirochete motility |
||
− | ** May develop jaundice, renal failure, arrhythmias, pulmonary symptoms, [[Causes::aseptic meningitis]], non-purulent conjunctival injection, photophobia, eye pain, muscle tenderness, adenopathy, and [[Causes::hepaosplenomegaly]] |
||
+ | **Also hooked ends |
||
− | * '''Weil disease''' (liver and renal failure) may develop during or directly following the acute phase |
||
+ | |||
− | ** Liver injury is predominantly jaundice with only mild liver enzyme rise |
||
+ | ==Clinical Manifestations== |
||
− | ** Renal failure |
||
+ | |||
− | *** ''Nonoliguric'' hypokalemia with impaired sodium reabsorption and increased distal sodium delivery |
||
+ | *Spectrum of severity, from asymptomatic seroconversion (most common) to nonspecific febrile illness to severe, life-threating multiorgan failure |
||
− | *** Selective loss of ENaC channels in proximal ubule |
||
+ | **Asymptomatic disease is likely frequent, given high seroprevalence in some populations |
||
− | *** Biopsy shows AIN |
||
+ | *Incubation period [[Usual incubation period::10 days]] (range [[Incubation period range::5 to 14 days]]) |
||
− | * '''Severe pulmonary hemorrhage syndrome''' (SPHS) |
||
+ | *'''Acute febrile phase''' |
||
− | ** May have frank hemoptysis, but not always |
||
+ | **Acute phase lasts 5 to 7 days |
||
− | ** Can show up as CXR lower lobe "snowflake-like" densities |
||
+ | **Starts with high [[fever]], [[headache]], chills, rigors, and [[myalgias]] |
||
− | * Arrhythmias, including atrial fibrillation and ventricular tachycardia |
||
+ | **Conjunctival injection is an identifying feature |
||
− | * Circulatory shock |
||
+ | **Muscle tenderness, especially in the calf and lumbar areas, is also characteristic |
||
− | ** Rarely, congestive heart failure from myocarditis |
||
+ | **Occasionally have a pretibial papular eruption |
||
− | * Severe disease has high mortality from 5 to 40% |
||
+ | **Can also have [[lymphadenopathy]], [[splenomegaly]], and [[hepatomegaly]] |
||
+ | **Mild leukocytosis and neutrophilia, with thrombocytopenia and occasionally anemia |
||
+ | **Spirochetes detectable in blood and CSF, possibly urine |
||
+ | *'''Immune phase''' |
||
+ | **Lasts 4 to 30 days |
||
+ | **Corresponds with the appearance of IgM antibodies |
||
+ | **Spirochete is cleared from blood and CSF but detectable in other organs, including urine |
||
+ | **May develop [[Causes::jaundice]], [[Causes::acute renal failure]], [[Causes::arrhythmias]], pulmonary symptoms, [[Causes::aseptic meningitis]], [[Causes::non-purulent conjunctival injection]], [[Causes::photophobia]], eye pain, muscle tenderness, [[Causes::adenopathy]], and [[Causes::hepaosplenomegaly|Causes::hepatosplenomegaly]] |
||
+ | *'''Weil disease''' (liver and renal failure) may develop during or directly following the acute phase |
||
+ | **Liver injury is predominantly [[jaundice]] with only mild liver enzyme rise |
||
+ | **Renal failure |
||
+ | ***''Nonoliguric'' hypokalemia with impaired sodium reabsorption and increased distal sodium delivery |
||
+ | ***Selective loss of ENaC channels in proximal ubule |
||
+ | ***Biopsy shows AIN |
||
+ | *'''Severe pulmonary hemorrhage syndrome''' (SPHS) |
||
+ | **May have frank [[hemoptysis]], but not always |
||
+ | **Can show up as CXR lower lobe "snowflake-like" densities |
||
+ | *Arrhythmias, including atrial fibrillation and ventricular tachycardia |
||
+ | *Circulatory shock |
||
+ | **Rarely, congestive heart failure from myocarditis |
||
+ | *Severe disease has high mortality from 5 to 40% |
||
+ | |||
+ | ==Diagnosis== |
||
+ | |||
+ | *In general, use PCR if early in disease (<7 days) and ELISA IgM followed by confirmatory MAT if further in disease (≥7 days) |
||
− | == Diagnosis == |
||
− | * In general, use PCR if early in disease (<7 days) and ELISA IgM followed by confirmatory MAT if further in disease (≥7 days) |
||
{| class="wikitable" |
{| class="wikitable" |
||
− | ! |
+ | !Method!!Sens!!Spec |
|- |
|- |
||
− | | |
+ | |Culture||5-50%||100% |
|- |
|- |
||
− | | |
+ | |Darkfield microscopy||40%||60% |
|- |
|- |
||
− | | |
+ | |Microscopic agglutination test (MAT)||90%||>90% |
|- |
|- |
||
− | | |
+ | |ELISA IgM||>90%||88-95% |
|- |
|- |
||
− | | |
+ | |Latex agglutination||92%||95% |
|- |
|- |
||
− | | |
+ | |Lateral flow assay||81%||96% |
|- |
|- |
||
− | | |
+ | |PCR||100%||93% |
|} |
|} |
||
− | === |
+ | ===Microscopy=== |
+ | |||
− | * Leptospires can be seen directly under darkfield microscopy |
||
+ | *Leptospires can be seen directly under darkfield microscopy |
||
− | * Low sensitivity and specificity of blood and urine samples, even if spirochetes are seen (as spirochetes can also be normal flora) |
||
+ | *Low sensitivity and specificity of blood and urine samples, even if spirochetes are seen (as spirochetes can also be normal flora) |
||
+ | |||
+ | ===Culture=== |
||
+ | |||
+ | *Can get positive cultures from blood and CSF, ideally when collected while febrile and before antibiotics |
||
+ | *Can inoculate one to blood drops directly into culture at bedside |
||
+ | *Urine can be cultured after the first week of illness, but need to be processed quickly |
||
+ | *Use Fletcher's medium (commercial version) |
||
+ | *Not very sensitive, and cultures can take weeks |
||
+ | |||
+ | ===Serology=== |
||
+ | |||
+ | *Detects IgM antibodies, which appear around day 5 to 7 |
||
+ | *Microscopic agglutination test (MAT) for antigen detection (Sn 90%, Sp 90%) |
||
+ | **''Leptospira'' antigens are mixed with serum and monitored for agglutination |
||
+ | **Monitor for a four-fold rise in titres from acute-phase to convalescent phase (repeat 4 to 6 weeks), or a single titre of at least 1:800 |
||
+ | **May cross-react with [[syphilis]], [[relapsing fever]], [[Lyme disease]], [[viral hepatitis]], HIV, [[Legionella]], and autoimmune diseases |
||
+ | **Cross-reacts between different serogroups |
||
+ | *IgM ELISA, needs confirmation by MAT (Sn 90%, Sp 90%) (this is the test in Canada) |
||
+ | *Latex agglutination test, needs confirmation by MAT (Sn 80%, Sp 95%) |
||
+ | *Lateral flow test, needs confirmation by MAT (Sn 80%, Sp 95%) |
||
+ | |||
+ | ===PCR=== |
||
+ | |||
+ | *Loop-mediated isothermal amplification (LAMP) assays and other PCR assays exist |
||
+ | *Unclear sensitivity and specificity, but has the potential to diagnose disease before antibodies develop |
||
+ | *Usually done from blood, but can try in urine as well |
||
+ | ==Differential Diagnosis== |
||
− | === Culture === |
||
− | * Can get positive cultures from blood and CSF, ideally when collected while febrile and before antibiotics |
||
− | * Can inoculate one to blood drops directly into culture at bedside |
||
− | * Urine can be cultured after the first week of illness, but need to be processed quickly |
||
− | * Use Fletcher's medium (commercial version) |
||
− | * Not very sensitive, and cultures can take weeks |
||
+ | *Early in disease, it is essentially a non-specific febrile syndrome |
||
− | === Serology === |
||
+ | *'''Viral''' |
||
− | * Detects IgM antibodies, which appear around day 5 to 7 |
||
+ | **[[Influenza]] |
||
− | * Microscopic agglutination test (MAT) for antigen detection (Sn 90%, Sp 90%) |
||
+ | **Acute [[HIV]] |
||
− | ** ''Leptospira'' antigens are mixed with serum and monitored for agglutination |
||
+ | **[[Infectious mononucleosis]] ([[EBV]]/[[CMV]]) |
||
− | ** Monitor for a four-fold rise in titres from acute-phase to convalescent phase (repeat 4 to 6 weeks), or a single titre of at least 1:800 |
||
+ | **Flaviviruses: [[dengue virus]], [[yellow fever virus]], [[West Nile virus]] |
||
− | ** May cross-react with [[syphilis]], [[relapsing fever]], [[Lyme disease]], [[viral hepatitis]], HIV, [[Legionella]], and autoimmune diseases |
||
+ | **Alphaviruses: [[Chikungunya virus]] |
||
− | ** Cross-reacts between different serogroups |
||
+ | **Bunyaviruses: [[Hantavirus]], [[Lassa fever virus]] |
||
− | * IgM ELISA, needs confirmation by MAT (Sn 90%, Sp 90%) (this is the test in Canada) |
||
+ | **Other [[viral hemorrhagic fever virus]] |
||
− | * Latex agglutination test, needs confirmation by MAT (Sn 80%, Sp 95%) |
||
+ | **[[Viral hepatitis]] |
||
− | * Lateral flow test, needs confirmation by MAT (Sn 80%, Sp 95%) |
||
+ | **[[Measles virus]], with cough and conjunctivitis |
||
+ | *'''Bacterial''' |
||
+ | **[[Rickettsioses]], including [[Rocky Mountain spotted fever]] |
||
+ | **[[Borreliosis]] |
||
+ | **[[Brucella]] |
||
+ | **[[Enteric fever]] |
||
+ | *'''Parasitic''' |
||
+ | **[[Malaria]] |
||
− | == |
+ | ==Management== |
− | * Loop-mediated isothermal amplification (LAMP) assays and other PCR assays exist |
||
− | * Unclear sensitivity and specificity, but has the potential to diagnose disease before antibodies develop |
||
− | * Usually done from blood, but can try in urine as well |
||
+ | *Treat early in disease course, usually before diagnosis |
||
− | == Differential Diagnosis == |
||
+ | *Usual treatment is [[Is treated by::penicillin]] G 1.5 MU IV q6h, if severe, or [[Is treated by::doxycycline]] 100 mg po bid, if mild |
||
− | * Early in disease, it is essentially a non-specific febrile syndrome |
||
+ | **May be able to use [[Is treated by::amoxicillin]], [[Is treated by::ampicillin]], [[Is treated by::ceftriaxone]], or [[Is treated by::azithromycin]] as alternatives |
||
− | * '''Viral''' |
||
+ | **May develop a Jarisch-Herxheimer reaction during treatment (only with beta-lactams) |
||
− | ** [[Influenza]] |
||
+ | **Duration is 5 to 7 days (except 3 days for [[azithromycin]] |
||
− | ** Acute [[HIV]] |
||
+ | *Close monitor and intensive supportive therapy required for severe patient |
||
− | ** [[Infectious mononucleosis]] ([[EBV]]/[[CMV]]) |
||
+ | *May need hemodialysis, but usually recovers renal function |
||
− | ** Flaviviruses: [[dengue virus]], [[yellow fever virus]], [[West Nile virus]] |
||
+ | *SPHS is managed as ARDS with lung-protective ventilation |
||
− | ** Alphaviruses: [[Chikungunya virus]] |
||
− | ** Bunyaviruses: [[Hantavirus]], [[Lassa fever virus]] |
||
− | ** Other [[viral hemorrhagic fever virus]] |
||
− | ** [[Viral hepatitis]] |
||
− | ** [[Measles virus]], with cough and conjunctivitis |
||
− | * '''Bacterial''' |
||
− | ** [[Rickettsioses]], including [[Rocky Mountain spotted fever]] |
||
− | ** [[Borreliosis]] |
||
− | ** [[Brucella]] |
||
− | ** [[Enteric fever]] |
||
− | * '''Parasitic''' |
||
− | ** [[Malaria]] |
||
− | == |
+ | ==Prevention== |
− | * Treat early in disease course, usually before diagnosis |
||
− | * Usual treatment is [[Is treated by::penicillin]] G 1.5 MU IV q6h, if severe, or [[Is treated by::doxycycline]] 100 mg po bid, if mild |
||
− | ** May be able to use [[Is treated by::amoxicillin]], [[Is treated by::ampicillin]], [[Is treated by::ceftriaxone]], or [[Is treated by::azithromycin]] as alternatives |
||
− | ** May develop a Jarisch-Herxheimer reaction during treatment (only with beta-lactams) |
||
− | ** Duration is 5 to 7 days (except 3 days for [[azithromycin]] |
||
− | * Close monitor and intensive supportive therapy required for severe patient |
||
− | * May need hemodialysis, but usually recovers renal function |
||
− | * SPHS is managed as ARDS with lung-protective ventilation |
||
+ | *Mostly avoidance of high-risk exposures |
||
− | == Prevention == |
||
+ | *Immunization is possible but rarely done, and covers only specific serovars |
||
− | * Mostly avoidance of high-risk exposures |
||
+ | **Even if immunizing animals, it prevents disease but not asymptomatic carriage |
||
− | * Immunization is possible but rarely done, and covers only specific serovars |
||
+ | *Can do chemoprophylaxis of high risk occupations with [[doxycycline]] 200 mg PO once weekly |
||
− | ** Even if immunizing animals, it prevents disease but not asymptomatic carriage |
||
− | * Can do chemoprophylaxis of high risk occupations with [[doxycycline]] 200 mg PO once weekly |
||
{{DISPLAYTITLE:''Leptospira'' species}} |
{{DISPLAYTITLE:''Leptospira'' species}} |
Revision as of 17:19, 10 August 2020
Background
Microbiology
- Thin, flagellated spirochete
- Best viewed with darkfield microscopy
- Species and serovars are divided into three broad categories within the genus Leptospira
- Pathogens: L. interrogans (multiple serovars, most common), L. noguchii, L. borgpetersenii, L. santarosai, L. kirschneri, L. weilii, L. alexanderi, L. alstonii, L. meyeri, L. wolffi, and L. kmetyi
- Non-pathogenic saprophytes: L. biflexa, L. wolbachii, L. vanthielii, L. terpstrae, L. yanagawae, and L. idonii
- Species of indeterminate pathogenicity: L. inadai, L. fainei, L. broomii, and L. licerasiae
- Within each species, there may be multiple serovars that are defined based on lipopolysaccharide (LPS) O-antigens
- A single species may have pathogenic and non-pathogenic serovars
Epidemiology
- Endemic worldwide
- More common during rainy seasons in tropical regions and late summer to fall in temperate regions
- In US, more common in Hawaii
- Major reservoir is as a chronic kidney infection in animals, especially rodents
- Among livestock, may cause spontaneous abortions
- Most common risk factor is exposure to water or soil contaminated with rodent urine
- Includes occupational exposures and direct contact
- High-risk occupations include farmers, slaughterhouse workers, pet traders, veterinarians, rodent catchers and sewer workers
- Leptospires can survive in water or soil for months, depending on the conditions
Pathophysiology
- Bacteria enter through cuts and abrasions, mucous membranes, conjunctivae, and inhalation
- After entering, it disseminates hematogenously
- Human TLR4 cannot bind leptospiral LPS
- Virulence factors
- Sphingomyelinase and hemolysin
- Also spirochete motility
- Also hooked ends
Clinical Manifestations
- Spectrum of severity, from asymptomatic seroconversion (most common) to nonspecific febrile illness to severe, life-threating multiorgan failure
- Asymptomatic disease is likely frequent, given high seroprevalence in some populations
- Incubation period 10 days (range 5 to 14 days)
- Acute febrile phase
- Acute phase lasts 5 to 7 days
- Starts with high fever, headache, chills, rigors, and myalgias
- Conjunctival injection is an identifying feature
- Muscle tenderness, especially in the calf and lumbar areas, is also characteristic
- Occasionally have a pretibial papular eruption
- Can also have lymphadenopathy, splenomegaly, and hepatomegaly
- Mild leukocytosis and neutrophilia, with thrombocytopenia and occasionally anemia
- Spirochetes detectable in blood and CSF, possibly urine
- Immune phase
- Lasts 4 to 30 days
- Corresponds with the appearance of IgM antibodies
- Spirochete is cleared from blood and CSF but detectable in other organs, including urine
- May develop jaundice, acute renal failure, arrhythmias, pulmonary symptoms, aseptic meningitis, non-purulent conjunctival injection, photophobia, eye pain, muscle tenderness, adenopathy, and Causes::hepatosplenomegaly
- Weil disease (liver and renal failure) may develop during or directly following the acute phase
- Liver injury is predominantly jaundice with only mild liver enzyme rise
- Renal failure
- Nonoliguric hypokalemia with impaired sodium reabsorption and increased distal sodium delivery
- Selective loss of ENaC channels in proximal ubule
- Biopsy shows AIN
- Severe pulmonary hemorrhage syndrome (SPHS)
- May have frank hemoptysis, but not always
- Can show up as CXR lower lobe "snowflake-like" densities
- Arrhythmias, including atrial fibrillation and ventricular tachycardia
- Circulatory shock
- Rarely, congestive heart failure from myocarditis
- Severe disease has high mortality from 5 to 40%
Diagnosis
- In general, use PCR if early in disease (<7 days) and ELISA IgM followed by confirmatory MAT if further in disease (≥7 days)
Method | Sens | Spec |
---|---|---|
Culture | 5-50% | 100% |
Darkfield microscopy | 40% | 60% |
Microscopic agglutination test (MAT) | 90% | >90% |
ELISA IgM | >90% | 88-95% |
Latex agglutination | 92% | 95% |
Lateral flow assay | 81% | 96% |
PCR | 100% | 93% |
Microscopy
- Leptospires can be seen directly under darkfield microscopy
- Low sensitivity and specificity of blood and urine samples, even if spirochetes are seen (as spirochetes can also be normal flora)
Culture
- Can get positive cultures from blood and CSF, ideally when collected while febrile and before antibiotics
- Can inoculate one to blood drops directly into culture at bedside
- Urine can be cultured after the first week of illness, but need to be processed quickly
- Use Fletcher's medium (commercial version)
- Not very sensitive, and cultures can take weeks
Serology
- Detects IgM antibodies, which appear around day 5 to 7
- Microscopic agglutination test (MAT) for antigen detection (Sn 90%, Sp 90%)
- Leptospira antigens are mixed with serum and monitored for agglutination
- Monitor for a four-fold rise in titres from acute-phase to convalescent phase (repeat 4 to 6 weeks), or a single titre of at least 1:800
- May cross-react with syphilis, relapsing fever, Lyme disease, viral hepatitis, HIV, Legionella, and autoimmune diseases
- Cross-reacts between different serogroups
- IgM ELISA, needs confirmation by MAT (Sn 90%, Sp 90%) (this is the test in Canada)
- Latex agglutination test, needs confirmation by MAT (Sn 80%, Sp 95%)
- Lateral flow test, needs confirmation by MAT (Sn 80%, Sp 95%)
PCR
- Loop-mediated isothermal amplification (LAMP) assays and other PCR assays exist
- Unclear sensitivity and specificity, but has the potential to diagnose disease before antibodies develop
- Usually done from blood, but can try in urine as well
Differential Diagnosis
- Early in disease, it is essentially a non-specific febrile syndrome
- Viral
- Influenza
- Acute HIV
- Infectious mononucleosis (EBV/CMV)
- Flaviviruses: dengue virus, yellow fever virus, West Nile virus
- Alphaviruses: Chikungunya virus
- Bunyaviruses: Hantavirus, Lassa fever virus
- Other viral hemorrhagic fever virus
- Viral hepatitis
- Measles virus, with cough and conjunctivitis
- Bacterial
- Parasitic
Management
- Treat early in disease course, usually before diagnosis
- Usual treatment is penicillin G 1.5 MU IV q6h, if severe, or doxycycline 100 mg po bid, if mild
- May be able to use amoxicillin, ampicillin, ceftriaxone, or azithromycin as alternatives
- May develop a Jarisch-Herxheimer reaction during treatment (only with beta-lactams)
- Duration is 5 to 7 days (except 3 days for azithromycin
- Close monitor and intensive supportive therapy required for severe patient
- May need hemodialysis, but usually recovers renal function
- SPHS is managed as ARDS with lung-protective ventilation
Prevention
- Mostly avoidance of high-risk exposures
- Immunization is possible but rarely done, and covers only specific serovars
- Even if immunizing animals, it prevents disease but not asymptomatic carriage
- Can do chemoprophylaxis of high risk occupations with doxycycline 200 mg PO once weekly