Medical Academic (MA): Why is it so important for travellers to take antimalarial medication exactly as prescribed, including starting treatment before travel, taking it daily at the same time while in a malaria-endemic area, and completing the full course after returning home?

Prof Tiaan de Jager (TdJ): Antimalarial prophylaxis only works when adequate drug levels are maintained in the bloodstream before, during and after exposure. Starting medication before travel ensures protective concentrations are achieved before entering a malaria-endemic area, while continuing after leaving protects against parasites that may have been acquired shortly before departure and are still developing in the liver or bloodstream. Poor adherence significantly reduces protection and increases the risk of malaria. Importantly, prophylaxis should always be combined with mosquito bite prevention measures, including insect repellents, appropriate clothing and insecticide-treated bed nets where appropriate.

MA: How much does missing doses or failing to complete the prescribed course reduce the effectiveness of antimalarial prophylaxis, and what are the most common reasons for poor adherence?

TdJ: The effectiveness of prophylaxis depends heavily on adherence. Missing doses reduces drug concentrations below protective levels and may leave travellers vulnerable to infection. Studies consistently show that poor adherence is one of the leading reasons travellers develop malaria despite having been prescribed prophylaxis. Common reasons include forgetting doses, concerns about side effects, misunderstanding when to stop medication, cost, complicated dosing schedules, or a mistaken belief that there is little risk after leaving the endemic area.

MA: Malaria symptoms often resemble influenza or other viral illnesses. How frequently does this lead to delayed diagnosis, and what clinical features should prompt healthcare professionals to suspect malaria instead?

TdJ: Delayed diagnosis remains one of the major contributors to severe malaria in returning travellers because early symptoms—fever, headache, muscle aches, chills and fatigue—are non-specific. Every patient presenting with fever who has travelled to, or lived in, a malaria-endemic area within the previous year should be evaluated for malaria, regardless of whether prophylaxis was taken. Clinicians should maintain a high index of suspicion, particularly during the first few weeks after return from endemic regions.

MA: Why is early diagnosis and prompt treatment so critical in malaria, and how quickly can uncomplicated malaria progress to severe or life-threatening disease if left untreated?

TdJ: Plasmodium falciparum, the predominant malaria species in sub-Saharan Africa, can progress rapidly from uncomplicated illness to severe malaria within 24- to 48-hours if not treated promptly. Severe malaria can lead to cerebral malaria, severe anaemia, kidney failure, respiratory distress and multi-organ failure. Early diagnosis and treatment are therefore lifesaving and substantially reduce the risk of complications and death.

MA: What diagnostic tests are currently recommended for confirming malaria, and what should healthcare professionals know about the role of rapid diagnostic tests compared with blood smear microscopy?

TdJ: The gold standard remains microscopic examination of thick and thin blood smears because it confirms infection, identifies the malaria species and estimates parasite density, which is important for clinical management. Rapid diagnostic tests (RDTs) are valuable where microscopy is unavailable or immediate results are needed, and they have greatly improved access to diagnosis in many settings. However, RDTs cannot quantify parasite density, may remain positive after successful treatment, and can occasionally produce false-negative results. If clinical suspicion remains high despite a negative RDT, repeat testing and microscopy are recommended.

MA: How should healthcare professionals approach malaria prevention in patients with special considerations, such as pregnancy, renal impairment, or a history of adverse reactions to antimalarial medicines, particularly when patients are reluctant to use prophylaxis because of previous side effects?

TdJ: These patients require an individualised risk-benefit assessment. Pregnant women are particularly vulnerable to severe malaria and adverse pregnancy outcomes, making prevention especially important. Drug choice should be guided by destination, parasite resistance patterns, gestational age, renal or hepatic function, co-morbidities and previous adverse reactions. Healthcare professionals should reassure patients that several effective prophylactic options exist, and previous intolerance to one medicine does not necessarily preclude the use of another. Counselling should focus on selecting the safest appropriate regimen while reinforcing the importance of mosquito bite prevention.

MA: What are the most important drug interactions and contraindications clinicians should consider before prescribing antimalarial prophylaxis, and how should concomitant medicines influence the choice of agent?

TdJ: A careful medication history is essential before prescribing prophylaxis. Important considerations include interactions with anticoagulants, antiepileptic medicines, certain antibiotics, antiretroviral therapy, immunosuppressants and drugs that prolong the QT interval. Some antimalarials are contraindicated in patients with significant psychiatric disorders, seizure disorders or severe renal impairment. The choice of prophylactic agent should therefore be individualised based on the patient's medical history, current medications, travel destination, duration of travel and local resistance patterns.

MA: There are several myths surrounding malaria prevention, including the belief that quinine-containing tonic water or ivermectin can prevent malaria. What does the evidence show about these claims, and what advice should healthcare professionals give to patients?

TdJ: There is no scientific evidence that commercially available tonic water prevents malaria. The quinine concentration is far below therapeutic or prophylactic levels. Likewise, ivermectin is not approved or recommended for malaria prevention in travellers. While ivermectin has been investigated in research programmes because mosquitoes die after feeding on treated individuals, it is not an established prophylactic medicine for human travellers. Healthcare professionals should advise patients to rely only on evidence-based preventive strategies: appropriate chemoprophylaxis prescribed according to current guidelines, mosquito bite avoidance measures, and seeking immediate medical attention for any fever during or after travel to a malaria-endemic area.

 

Conclusion

From the UP ISMC perspective, malaria prevention should always combine three complementary approaches: Appropriate chemoprophylaxis where indicated, effective personal protection against mosquito bites, and rapid diagnosis with prompt treatment of any suspected malaria. No single intervention provides complete protection. Travellers should also be reminded that no prophylactic regimen is 100% effective. Therefore, any fever occurring during travel or within weeks to months after returning from a malaria-endemic area should be considered malaria until proven otherwise. Early recognition and treatment remain the most effective means of preventing severe disease and saving lives. The UP Senate approved a Travel Clinic that will also be able to support the general public with travel advise, including malaria.  It will be operated from the Sport Exercise Medicine and Lifestyle Institute Clinical Services platform on the Hillcrest campus of the UP. For more information, go to: www.malaria.up.ac.za

 

Prof Tiaan de Jager is Director of the UP ISMC and Director of the South African Medical Research Council Collaborating Centre for Malaria Research. He is also Professor of Environmental Health in the School of Health Systems and Public Health at the University of Pretoria. Prof De Jager served as Dean of the Faculty of Health Sciences from 2017 to 2025, following his tenure as Acting Dean and Deputy Dean: Research. With more than three decades of academic and research experience, his work focuses on environmental health, malaria control and sustainable public health interventions.

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