A study detected contrasting patterns of drug resistance in malaria-causing parasites taken from both humans and mosquitoes. Parasites found in human blood samples showed a high prevalence for pyrimethamine-resistance, which was consistent with the class of drugs widely used to treat malaria. However, parasites taken from mosquitoes themselves had very low prevalence of pyrimethamine-resistance and a high prevalence of cycloguanil-resistant mutants indicating resistance to a newer class of antimalaria drug not widely used in Zambia.