and anemia develop . C is for Chloroquine Until recently , Chloroquine , an anti-malarial drug , was the first option for many people because of its relatively low price and effectiveness . However , resistance to Chloroquine in many parts of the world has rendered the drug ineffective . D is for Diagnosis After noting your symptoms and travel history , your doctor will likely obtain a sample of your blood for observation . Two blood samples , taken at six - and 12-hour intervals , can usually confirm the presence of the malaria parasite and its type . It is possible to be infected by more than one parasite at the same time . E is for Epidemic According to the World Health Organization -LRB- WHO -RRB- , large and devastating epidemics can occur when the mosquito-borne parasite is introduced into areas where people have had little prior contact with the infecting parasite . These epidemics can be triggered by wet weather conditions and further aggravated by floods or mass population movements driven by conflict . F is for Fever The most common symptom of all types of malarias is high fever , which is why doctors often
LONDON , England -- Malaria is one of the world 's worst health problems and one of its biggest killers , with half a billion people affected every year , according to the Roll Back Malaria partnership . Around half a billion people are infected with malaria every year . Ninety percent of those cases are in Africa . Saturday marks World Malaria Day , when the world commemorates global efforts to eradicate the disease . Below CNN 's Vital Signs has produced a complete A - Z guide to how malaria spreads , the symptoms to look out for and how to protect yourself . A is for Anti-malarial drugs The history of anti-malarial medicine has been marked by a constant struggle between evolving drug-resistant parasites and the search for new drugs . Currently , anti-malaria experts are focusing on therapies that combine several drugs for better effects . B is for Blood stream Once a mosquito has bitten and the malaria parasites reach the liver , the parasites divide and create thousands of mature parasites . These are released into the blood and infect red blood cells . At that point , typical malaria symptoms such as fever