Immunization With Plasmodium Falciparum Sporozoites Under Chloroquine Versus Mefloquine Prophylaxis

Inclusion Criteria: 1. Age \> 18 and \< 35 years healthy volunteers (males or females) 2. Good health based on history and clinical examination 3. Negative pregnancy test 4. Use of adequate contraception for females 5. Signing of the informed consent form, thereby demonstrating understanding of the meaning and procedures of the study 6. Agreement to inform the general practitioner and to sign a request to release medical information concerning contra-indications for participation in the study 7. Willingness to undergo a Pf controlled infection through mosquito bites 8. Agreement to stay in a hotel room close to the trial center during a part of the study (Day 5 after challenge till treatment is finished) 9. Reachable (24/7) by mobile phone during the whole study period 10. Available to attend all study visits 11. Agreement to refrain from blood donation to Sanquin or for other purposes, during the whole study period 12. Willingness to undergo HIV, hepatitis B and hepatitis C tests 13. Negative urine toxicology screening test at screening visit and the day before challenge 14. Willingness to take a prophylactic regime of chloroquine or mefloquine and curative regimen of Malarone® Exclusion Criteria: 1. History of malaria 2. Plans to travel to malaria endemic areas during the study period 3. Plans to travel outside of the Netherlands during the challenge period 4. Previous participation in any malaria vaccine study and/or positive serology for Pf 5. Symptoms, physical signs and laboratory values suggestive of systemic disorders including renal, hepatic, cardiovascular, pulmonary, skin, immunodeficiency, psychiatric, and other conditions which could interfere with the interpretation of the study results or compromise the health of the volunteers 6. History of diabetes mellitus or cancer (except basal cell carcinoma of the skin) 7. History of arrhythmias or prolonged QT-interval 8. Positive family history in 1st and 2nd degree relatives for cardiac events \< 50 years old 9. An estimated, ten year risk of fatal cardiovascular disease of ≥5%, as estimated by the Systematic Coronary Risk Evaluation (SCORE) system 10. Clinically significant abnormalities in electrocardiogram (ECG) at screening 11. Body Mass Index (BMI) below 20 or above 30 kg/m2 12. Any clinically significant deviation from the normal range in biochemistry or hematology blood tests or in urine analysis 13. Positive HIV, HBV or HCV tests 14. Participation in any other clinical study within 30 days prior to the onset of the study 15. Enrollment in any other clinical study during the study period 16. For women: pregnancy or lactation 17. Volunteers unable to give written informed consent 18. Volunteers unable to be closely followed for social, geographic or psychological reasons 19. History of drug or alcohol abuse interfering with normal social function 20. A history of treatment for psychiatric disease or moderate or severe psychological episode in volunteer 21. A history of convulsions in volunteer 22. Severe depression, anxiety disorder of psychosis in first or second degree family 23. Contra-indications to Malarone®, chloroquine or mefloquine including hypersensitivity or treatment taken by the volunteer that interferes with Malarone®, chloroquine or mefloquine 24. The use of chronic immunosuppressive drugs, antibiotics, or other immune modifying drugs within three months of study onset (inhaled and topical corticosteroids and oral anti-histaminic are allowed) and during the study period 25. Any confirmed or suspected immunosuppressive or immunodeficient condition, including asplenia 26. Co-workers or trainees of the departments of Medical Microbiology, Parasitology, or Internal Medicine of the Leiden University medical Centre 27. A history of sickle cell anemia, sickle cell trait, thalassemia, thalassemia trait or G6PD deficiency