Malaria Challenge With NF54 Strain

Inclusion Criteria: * Male or nonpregnant female between the ages of 18 and 40 years, inclusive. * Women who are not surgically sterile (no history of bilateral tubal ligation, bilateral salpingo-oophorectomy, or hysterectomy), post-menopausal (1 year without menses) or determined otherwise by medical evaluation to be sterile must agree to practice adequate contraception \[such as double barrier methods (condoms plus foam or spermicide, diaphragm plus foam or spermicide), some intrauterine devices (IUDs), intravaginal or transdermal hormonal methods initiated at least 1 month prior to inoculation, or a vasectomized partner\] for the entire study period (56 days). Serologic pregnancy tests will be conducted upon screening. Urine testing will be done on the day of malaria challenge, on the day of the first positive malaria smear and at the conclusion of active surveillance (Day 56). * Is in good health, as determined by vital signs (heart rate, blood pressure, oral temperature), medical history, screening 12-lead electrocardiogram (ECG) and a physical examination. * Has normal laboratory values \[urinalysis (assessing blood and protein presence as greater than trace by dipstick), hemoglobin, white blood cells, platelet count, aspartate aminotransferase (AST), (alanine aminotransferase) ALT, glucose and creatinine\] prior to challenge study. * Able to understand and comply with planned study procedures including an inpatient stay from Day 8-18 after malaria challenge. * Provides informed consent prior to any study procedures, correctly answers greater than or equal to 70 percent on the post consent quiz and is available for all study visits. * Willing to avoid non-study related blood donation for 3 years following Plasmodium falciparum challenge. Exclusion Criteria: * Has any known history of malaria infection, is a long-term resident (\> 5 years) of a malaria-endemic area, was born and resided in a malaria-endemic area, or has traveled to a malaria-endemic area within the previous 6 months. * Has a positive urine pregnancy test prior to malaria challenge (if female of childbearing potential), is lactating, or has the intention to become pregnant within 2 months after enrollment in this study. * Use of any antibiotic or antimalarial drug beginning 28 days prior to the screening and extending to Day 56 of study surveillance. * Has evidence of increased cardiovascular disease risk (defined as \> 10 percent, 5 year risk) as determined by the method of Gaziano. Risk factors include sex, age (years), systolic blood pressure (mm Hg), smoking status (current versus past or never), body mass index (BMI) (kg/mm\^2), reported diabetes status (yes/no), current treatment for raised blood pressure (yes/no). * Is immunosuppressed (e.g., poorly-controlled diabetes mellitus, cirrhosis, renal insufficiency, active malignancy, connective tissue disease, organ transplant) as a result of an underlying illness or treatment. * An abnormal electrocardiogram (EKG), defined as one showing pathologic Q waves and significant ST-T wave changes; left ventricular hypertrophy; any non-sinus rhythm excluding isolated premature atrial contractions; right or left bundle branch block; or advanced (secondary or tertiary) A-V heart block. * Has an active neoplastic disease (excluding nonmelanotic skin cancer) or neoplastic disease within the past 5 years or any history of hematologic malignancy. * Is using or intends to continue using oral or parenteral steroids, high-dose inhaled steroids (\>800 mcg/day of beclomethasone dipropionate or equivalent) or other immunosuppressive or cytotoxic drugs (an exception includes asthma for which any oral or inhaled steroid intake will mean exclusion from study enrollment). * Has a known active history of human immunodeficiency virus, hepatitis B surface antigen positivity, or hepatitis C infection. * Has a history of active alcohol or drug abuse in the last 5 years. * Has a history of receiving blood products within the 3 months prior to enrollment in this study. * Has a history of psoriasis or porphyria, which may be exacerbated after treatment with chloroquine. * Has an acute or chronic medical condition that, in the opinion of the investigator, would render malaria challenge unsafe or would interfere with the evaluation of responses (this includes, but is not limited to: known liver disease, renal disease, neurological disorders, visual field defects, cardiac disorders, pulmonary disorders, auditory damage, diabetes mellitus, and transplant recipients). * Has a history of anaphylactic response to mosquito bites or known allergy to chloroquine, 4-aminoquinoline derivatives \[atovaquone/proguanil (Malarone®)\], ibuprofen, or acetaminophen that may be used to treat volunteers developing malaria after Plasmodium falciparum challenge. * Is using or intends to continuing using a medication known to cause drug reactions with chloroquine or Malarone®, such as cimetidine, metoclopramide, antacids or kaolin (antacids and kaolin can be administered at least 4 hours from intake of chloroquine). * History of retinal or visual field changes, auditory damage, or seizures. * History of splenectomy. * Has known sickle cell trait or laboratory evidence of sickle cell trait. * Has an acute illness, including an oral temperature greater than 100.4 degrees Fahrenheit, within 1 week prior to malaria challenge. * Plans to undergo surgery (elective or otherwise) between enrollment and 4 weeks (28 days) post-challenge. * Received an experimental agent (vaccine, drug, biologic, device, blood product, or medication) within 1 month prior to enrollment in this study, or expects to receive an experimental agent during the 2-month post-challenge period. * Has a diagnosis of schizophrenia, bi-polar disease or other major psychiatric disease. * Has any condition that would, in the opinion of the site investigator, place the subject at an unacceptable risk of injury or render the subject unable to meet the requirements of the protocol.