II. Epidemiology
- Incidence: 1832 reported cases in U.S. in 2014
- Majority of cases occur April to September
- Tick Carriers
- Deer Tick (Ixodes Scapularis)
- Dog tick (Dermacentor variabilis)
- United States endemic areas (similar distribution to Lyme Disease)
- Upper Midwest including. Minnesota
- Wyoming
- Northeast including New York
III. Pathophysiology
- Transmission: Tick Borne
- Deer Tick Bite (Ixodes Tick)
- Small gram-negative organisms
- Pleomorphic
- Obligate intracellular organisms
- Infects Neutrophils
- Causative Organism (Rickettsial Disease)
- New Name: Anaplasma phagocytophila (Human Granulocytic Anaplasmosis or HGA)
- Prior Name: Ehrilichia phagocytophila (Human Granulocytic Ehrlichiosis, renamed in 2001)
- Similar organisms affect horses (E. equi) and dogs (E. ewingii)
IV. Risk Factors: Severe Cases
- Immunocompromised
- Immunosuppressant medications
- Organ transplant
- Cancer
- HIV infection
- Splenectomy
V. Symptoms
VI. Signs: Rash
- Occurs in <10% of patients (contrast with >30% in Ehrlichiosis)
- Characteristics vary
- May be maculopapular or petechial or appear with diffuse erythema
- Involves trunk, and spares hands and feet
- Not associated with Tick Bite site (unlike Erythema Migrans)
VII. Differential Diagnosis
- See Tick Borne Illness
- Similar to Ehrlichiosis presentation, and Rocky Mountain Spotted Fever Presentation (with different rash)
- Consider coinfection (Lyme Disease, Rocky Mountain Spotted Fever) carried by the same ticks
VIII. Labs
-
Complete Blood Count
- Leukopenia
- Thrombocytopenia (unique to Anaplasmosis compared with Babesia and Lymes Disease)
- Mild transient Anemia
-
Liver transaminases increased
- Aspartate Aminotransferase (AST) increased
- Alanine Aminotransferase (ALT) increased
- Whole Blood Anaplasma PCR (37% Sensitivity)
- Most sensitive in first 2 weeks of infection
- Anaplasma Serology
- Positive two weeks after onset
- Used for confirmation, not for diagnosis
- Anticipate a fourfold rise in Antibody titers on re-testing at 3-4 weeks
- Minimum peak 1:64
- Maximum peak 1:128 or higher dilution
- Other variably present laboratory findings
- Increased Erythrocyte Sedimentation Rate (ESR)
- Increased Blood Urea Nitrogen (BUN)
- Increased Serum Creatinine
IX. Management
- Antibiotic course: 7-14 days
- Preferred in all ages (even under age 8 years old)
- Doxycycline 2.3 mg/kg up to 100 mg oral or IV twice daily for 7 to 14 days
- Alternatives
- Tetracycline 500 mg orally four times daily for 7 to 14 days
- Rifampin 10 mg/kg up to 600 mg twice daily for 5 to 7 days
- May be used in pregnancy, but increasing resistance
X. Complications: Untreated Disease
- Meningoencephalitis
- Respiratory Failure
- Uncontrolled Bleeding
- Mortality 0.3% (contrast with 3% in Ehrlichiosis)
XI. Prognosis
- Severe disease and death are rare, but are more common in Immunocompromised patients
XII. Prevention
XIII. Resources
- CDC: Anaplasmosis
- Minnesota Department of Health
XIV. References
- (2016) Sanford Guide to Antibiotics app, accessed 4/12/2016
- (1995) MMWR Morb Mortal Wkly Rep 44:593-5 [PubMed]
- Fritz (1998) Infect Dis Clin North Am 12:123-36 [PubMed]
- Glushko (1997) Postgrad Med 101(6):225-30 [PubMed]
- McQuiston (1999) Emerg Infect Dis 5:635-42 [PubMed]
- Pace (2020) Am Fam Physician 101(9): 530-40 [PubMed]
- Weinstein (1996) Am Fam Physician 54(6):1971-6 [PubMed]
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Related Studies
Definition (MSH) | A species of gram-negative bacteria in the genus ANAPLASMA, family ANAPLASMATACEAE, formerly called Ehrlichia phagocytophila or Ehrlichia equi. This organism is tick-borne (IXODES) and causes disease in horses and sheep. In humans, it causes human granulocytic EHRLICHIOSIS. |
Concepts | Bacterium (T007) |
MSH | D041081 |
SnomedCT | 420364006, 422312006, 89725006, 4060003 |
LNC | LP17117-0, MTHU025859 |
English | Ehrlichia equi, Ehrlichia phagocytophila, Rickettsia phagocytophila, Anaplasma phagocytophilum (organism), Anaplasma phagocytophila, Anaplasma phagocytophilum (bacteria), Ehrlichia equi Lewis et al. 1988, Ehrlichia phagocytophila (Foggie 1949) Philip 1962 (Approved Lists 1980), Anaplasma phagocytophilum corrig. (Foggie 1949) Dumler et al. 2001, Cytoecetes bovis, Rickettsia phagocytophila ovis, Anaplasma phagocytophila (organism), Ehrlichia equi (organism), Ehrlichia phagocytophila (organism), Anaplasma phagocytophilum, HGE agent, agent of human granulocytic ehrlichiosis, human granulocytic Ehrlichia, Cytoecetes phagocytophila, HGE Agent |
Spanish | Anaplasma phagocytophilum (organismo), Ehrlichia equi, Anaplasma phagocytophilum, Anaplasma phagocytophila, Ehrlichia phagocytophila (organismo), Anaplasma phagocytophila (organismo), Ehrlichia equi (organismo), Ehrlichia phagocytophila, Agente de la Ehrlichiosis Granulocítica Humana, Agente de la EGH, Agente de la HGE, Cytoecetes phagocytophila |
Swedish | Anaplasma phagocytophilum |
Czech | Anaplasma phagocytophilum, Ehrlichia phagocytophila, Ehrlichia equi |
Finnish | Anaplasma phagocytophilum |
Italian | Erlichia equi, Agente dell'HGE, Ehrlichia phagocytophila, Anaplasma phagocytophilum |
Russian | ERLIKHIIA FAGOTSITOFIL'NAIA, ERLIKHIIA LOSHADINAIA, ЭРЛИХИЯ ЛОШАДИНАЯ, ЭРЛИХИЯ ФАГОЦИТОФИЛЬНАЯ |
Polish | Anaplasma phagocytophilum |
Portuguese | Agente da Ehrlichiose Granulocítica Humana, Agente da EGH, Anaplasma phagocytophilum, Ehrlichia equi, Ehrlichia phagocytophila, Agente da HGE, Cytoecetes phagocytophila |
French | Anaplasma phagocytophilum, Agent EGH, Agent HGE, Agent de l'ehrlichiose granulocytaire humaine, Cytoecetes phagocytophila, Ehrlichia equi, Ehrlichia phagocytophila |
German | Anaplasma phagocytophilum, Ehrlichia equi, Ehrlichia phagocytophila |
Dutch | Anaplasma phagocytophilum, Cytoecetes phagocytophilia, Ehrlichia equi, Ehrlichia phagocytophila, HGE-agent |
Ontology: Human anaplasmosis due to Anaplasma phagocytophilum (C0483368)
Concepts | Disease or Syndrome (T047) |
SnomedCT | 85708001 |
English | human granulocytic ehrlichiosis (diagnosis), human granulocytic ehrlichiosis, Human granulocytic ehrlichiosis, Human anaplasmosis due to Anaplasma phagocytophilum, Human granulocytic ehrlichiosis (disorder), Infection by Anaplasma phagocytophilum, Human anaplasmosis due to Anaplasma phagocytophilum (disorder) |
Spanish | anaplasmosis humana debida a Anaplasma phagocytophilum (trastorno), ehrliquiosis granulocítica humana, ehrliquiosis granulocítica humana (trastorno), anaplasmosis humana debida a Anaplasma phagocytophilum, Ehrlichiosis granulocítica humana |
Portuguese | Ehrliquiose granulocítica humana |
Italian | Ehrlichiosi granulocitica dell'uomo |
German | humane Granulozyten-Ehrlichiose |
French | Erhlichiose granulocytaire humaine |
Dutch | humane granulocyten-ehrlichiosis |
Czech | Lidská granulocytická ehrlichióza |
Japanese | ヒト顆粒球性エールリッヒア症, ヒトカリュウキュウセイエールリッヒアショウ |
Hungarian | Human granulocytás ehrlichiosis |
Ontology: Human anaplasmosis (C1960454)
Concepts | Disease or Syndrome (T047) |
SnomedCT | 427481004 |
English | Human anaplasmosis, Human anaplasmosis (disorder) |
Spanish | anaplasmosis humana (trastorno), anaplasmosis humana, Anaplasmosis humana |
Portuguese | Anaplasmose humana |
Italian | Anaplasmosi umana |
German | Humane Anaplasmose |
French | Anaplasmose humaine |
Dutch | humane anaplasmose |
Czech | Lidská anaplazmóza |
Japanese | ヒトアナプラズマショウ, ヒトアナプラズマ症 |
Hungarian | Humán anaplasmosis |