Ehrlichiosis ewingii infection is an infectious disease caused by an intracellular bacteria, Ehrlichia ewingii. The infection is transmitted to humans by the tick, Amblyomma americanum. This tick can also transmit Ehrlichia chaffeensis, the bacteria that causes human monocytic ehrlichiosis (HME). Symptoms and signs
Patients can present with fever, headache, myalgias, and malaise. Laboratory tests may reveal thrombocytopenia, leukopenia, and evidence of liver damage. Mechanism
Humans contract the disease after a bite by an infected tick of the species Amblyomma americanum. Those with an underlying immunodeficiency (such as HIV) appear to be at greater risk of contracting the disease. Compared to HME, ewingii ehrlichiosis has a decreased incidence of complications.Like Anaplasma phagocytophilum, the causative agent of human granulocytic ehrlichiosis, Ehrlichia ewingii infects neutrophils. Infection with E. ewingii may delay neutrophil apoptosis. Diagnosis
In endemic areas, a high index of suspicion is warranted, especially with a known exposure to ticks. The diagnosis can be confirmed by using PCR. A peripheral blood smear can also be examined for intracytoplasmic inclusions called morulae. Treatment
The treatment of choice is doxycycline. See also
Human monocytic ehrlichiosis
Human granulocytic ehrlichiosis
Ehrlichiosis (canine)

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They include the classical Huntingtons disease mimic or phenocopy syndromes, called Huntingtons disease-like syndrome types 1, 2 and 3; inherited prion disease, the spinocerebellar ataxias type 1, 3 and 17, neuroacanthocytosis, dentatorubral-pallidoluysian atrophy (DRPLA), brain iron accumulation disorders, Wilsons disease, benign hereditary chorea, Friedreichs ataxia, mitochondrial disease and Rett syndrome. Acquired causes
The most common acquired causes of chorea are cerebrovascular disease and, in the developing world, HIV infection—usually through its association with cryptococcal disease.Sydenhams chorea occurs as a complication of streptococcal infection. Twenty percent (20%) of children and adolescents with rheumatic fever develop Sydenhams chorea as a complication. It is increasingly rare, which may be partially due to penicillin, improved social conditions, and/or a natural reduction in the bacteria (Streptococcus) it has stemmed from. Psychological symptoms may precede or accompany this acquired chorea and may be relapsing and remitting. The broader spectrum of paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection can cause chorea and are collectively referred to as PANDAS.Chorea gravidarum refers to choreic symptoms that occur during pregnancy. If left untreated, the disease resolves in 30% of patients before delivery but, in the other 70%, it persists. The symptoms then progressively disappear in the next few days following the delivery.Chorea may also be caused by drugs (commonly levodopa, anti-convulsants and anti-psychotics).Other acquired causes include CSF leak, systemic lupus erythematosus, antiphospholipid syndrome,  kappa light-chain monoclonal gammopathy of undetermined significance, thyrotoxicosis, polycythaemia rubra vera, transmissible spongiform encephalopathies and coeliac disease. Treatment
There is no standard course of treatment for chorea.