By 1954, it was found that the mutant hemoglobin was highly prevalent in West Africa. In 1960, Vernon Ingram and J. A. Hunt at the University of Cambridge discovered that the mutation was a single amino acid replacement of glutamic acid with lysine. References
External links
Hemoglobin+C at the US National Library of Medicine Medical Subject Headings (MeSH)
Hemoglobin+C+Disease at the US National Library of Medicine Medical Subject Headings (MeSH)
There is very low quality evidence indicating that doxycycline use may be associated with an increased risk of indigestion, photosensitivity, vomiting, and yeast infections, when compared with mefloquine and atovaquone-proguanil. Causal prophylaxis
Causal prophylactics target not only the blood stages of malaria, but the initial liver stage as well. This means that the user can stop taking the drug seven days after leaving the area of risk. Malarone and primaquine are the only causal prophylactics in current use. Regimens
Specific regimens are recommended by the WHO, UK HPA and CDC for prevention of P. falciparum infection. HPA and WHO advice are broadly in line with each other (although there are some differences). CDC guidance frequently contradicts HPA and WHO guidance. These regimens include:

doxycycline 100 mg once daily (started one day before travel, and continued for four weeks after returning);
mefloquine 250 mg once weekly (started two-and-a-half weeks before travel, and continued for four weeks after returning);
atovaquone/proguanil (Malarone) 1 tablet daily (started one day before travel, and continued for 1 week after returning). Can also be used for therapy in some cases.In areas where chloroquine remains effective:

chloroquine 300 mg once weekly, and proguanil 200 mg once daily (started one week before travel, and continued for four weeks after returning);
hydroxychloroquine 400 mg once weekly (started one to two weeks before travel and continued for four weeks after returning)What regimen is appropriate depends on the person who is to take the medication as well as the country or region travelled to.