Treatment of West Nile Virus With MGAWN1

Inclusion Criteria:

1. Provide written informed consent

2. Be >=18 years of age at the time of enrollment

3. Have West Nile Fever defined as:

1. temperature >38°C, headache, AND

2. positive diagnostic test for WNV Ribonucleic acid or Immunoglobulin M with serum or cerebrospinal fluid (CSF)

OR have West Nile Neuroinvasive Disease (includes neurological signs and/or symptoms of West Nile meningitis, encephalitis, and/or acute flaccid paralysis), defined as:

• West Nile encephalitis (must meet criteria a and b below)

1. Encephalopathy (depressed or altered level of consciousness, lethargy, or personality change lasting 24 hours)

2. CSF pleocytosis >=5 cells/mm^3

AND/OR

• West Nile meningitis (must meet criteria c and d)

3. Clinical signs of meningeal inflammation, including nuchal rigidity, Kernig or Brudzinski sign, photophobia, or phonophobia

4. CSF pleocytosis >=5 cells/mm^3

AND/OR

• Acute flaccid paralysis (must meet criteria e and f)

5. Acute onset of limb weakness with marked progression over 48 hours

6. Two or more of the following conditions:

- asymmetry to weakness

- areflexia or hyporeflexia of affected limb(s)

- absence of pain, paresthesia, or numbness in affected limb(s)

- CSF pleocytosis >=5 cells/mm^3

- CSF elevated protein levels (4.5 g/L)

- electrodiagnostic studies consistent with an anterior horn cell process

- or abnormal increased signal in the anterior gray matter as documented by spinal cord magnetic resonance imaging

4. Have epidemiological factors consistent with West Nile Virus infection (must meet criterion a or b below):

1. Appropriate time of year for West Nile Virus transmission in region

2. Travel history to a region where West Nile Virus is active

5. Develop signs and/or symptoms within 14 days before study enrollment.

6. If female of childbearing potential or male and in a sexual relationship with a female of childbearing potential, agree (or have partner agree) to practice abstinence or use 2 of the following methods of contraception for 120 days (approximately 4 months) after study drug administration:

1. Oral contraceptives, or other form of hormonal birth control including hormonal vaginal rings or transdermal patches

2. An intrauterine device

3. Barrier contraception (condom) with a spermicide (i.e., female subject ensures use by male partner[s])

4. Any other equivalent method of contraception (as judged by the investigator)