Missing malaria? Potential obstacles to diagnosis and hypnozoite eradication

Recently, one of us experienced an episode of probable malaria on returning from fieldwork in the Solomon Islands. Although a clinical diagnosis of malaria was made, and the illness responded to empirical therapy with artemether–lumefantrine (Riamet, Novartis), a laboratory diagnosis was not achieved. Suspected malaria in travellers who have returned to Australia from overseas will present without notice and, owing to the often severe nature of this illness, will require immediate attention. This may occur in localities where personal consultation with an infectious diseases physician is not possible. Primaquine for the eradication of malarial hypnozoites from the liver may not be readily available. In this article, we aim to provide brief expert guidance on the diagnosis of malaria, the use of primaquine for eradication therapy and the implications of the limited availability of this treatment in Australia. Patients presenting with fever should be questioned about their travel history. Clinicians should be mindful that malarial relapse (Plasmodium vivax and P. ovale) or recrudescence (P. malariae) may occur months, or even years, after primary infection. Further, relapse may be the first symptomatic presentation. Therefore, any patient with pyrexia and a history of travel to an endemic area in the past 3 years might be considered as potentially having malaria.