Clinical Trial for the Development of a Safe Malaria Challenge Model That Can be Reproduced in Humans

Inclusion Criteria: * Healthy adults (male or non-pregnant, non-lactating female) 18 to 55 years of age; * Able to provide free and willing written informed consent to participate; * A score at least 80% correct on a 10 question Assessment of Understanding; * No plans to travel to a malaria endemic area during the course of the study; * Duffy positive phenotype; * Normal (non-deficient) G6PD phenotype (range : 4.6 to 13.5 u/gm hemoglobin); * Free of significant health problems as established by medical history and clinical examination completed prior to the study; * Available to participate and reachable by phone for duration of study (approximately 9 months starting from screening). * Only subjects with no or low cardiac risk factors according to the Gaziano study and a normal EKG will be included in the study Exclusion Criteria: * Pregnant or nursing at screening or plans to become pregnant or nurse from the time of enrollment until 6 months after sporozoite challenge; * Duffy negative phenotype; * G6PD deficiency or have any hemoglobinopathy by history; * Past infection with any species of malaria (as demonstrated by a positive thick smear) in the last 5 years; * History of receipt of treatment or prophylaxis for malaria during the previous 6 months; * History of receipt of malaria vaccine within the previous 5 years; * History of receipt of malaria challenge (being bitten by experimentally infected mosquitoes) within the previous 5 years; * Plans to travel to malarious areas during the study period; * Allergy to antimalarials or significant (e.g. systemic) hypersensitivity reactions to mosquito bites (local hypersensitivity reactions at the site of a mosquito bite are not an exclusion criterion); * History of psoriasis (given its interaction with chloroquine); * Use of any investigational or non-registered drug or vaccine within 30 days preceding the challenge or planned use during the study period; * Use or planned use of any drugs with significant anti-malarial activity, such as doxycycline, clindamycin, azithromycin, during the study period (volunteers can withhold the use of these medications during the study period, at the minimum starting from 4 weeks before the challenge until 4 weeks after becoming parasitemic); * Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection and history of splenectomy; * Administration of chronic (defined as more than 14 days) immunosuppressants or other immune-modifying drugs within six months of challenge; * For corticosteroids, this is defined as prednisone, or equivalent, 0.5 mg/kg/day; * Inhaled and topical steroids are allowed; * A family history of congenital or hereditary immunodeficiency; * Chronic or active neurologic disease including seizure disorder; * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic, or renal functional abnormality, as determined by medical history, physical examination, or abnormal baseline laboratory screening tests: * ALT above normal range (table 9); * Creatinine above normal range (table 9); * Hemoglobin below normal range (table 10); * Platelet count below normal range (table 10); * Total white cell count below normal range (table 10); * Acute disease at the time of enrollment * Acute disease is defined as the presence of a moderate or severe illness with or without fever; * Challenge can be administered to persons with a minor illness, such as diarrhea or mild upper respiratory infection without fever (i.e., oral temperature \< 38°C/100.4°F); * Hepatomegaly, right upper quadrant abdominal pain or tenderness; * Seropositive for HIV, hepatitis C virus (antibodies to HIV and HCV), and/or HBsAg; * Administration of immunoglobulins and/or any blood products within the 3 months preceding challenge or planned administration during the study period; * Suspected or known current alcohol abuse/drug abuse as obtained by history and physical examination; * Inability to make follow-up visits; * Any other significant finding that in the opinion of the investigator would increase the risk of having an adverse outcome from participating in this study.