In 2016, 91 countries reported a total of 216 million cases of malaria, an increase of 5 million cases over the previous year, and the estimated malaria deaths worldwide were 445,000 like in 2015. This suggests that despite a substantial reduction in the malaria burden observed since 2010, largely attributed to the scale-up of effective control measures (vector control interventions, efficacious antimalarial treatment), the rate of decline of both clinical cases and malaria deaths has stalled since 2014 and in some regions even reversed. Achieving universal access to standard control interventions, such as case management, implementation of vector control methods, seasonal malaria chemoprevention, and intermittent preventive treatment for pregnant women, remains a priority. It is essential to contain emerging drug resistance in malarial parasite and insecticide resistance in mosquito vector species. Additional new interventions to accelerate interruption of transmission are in crucial need for their rapid integration within the standard control activities. These integrated control approaches must be implemented at community level with the active involvement of the local populations to reach high coverage. Finally, political and financial supports should be maintained and even doubled to reach the 2030 targets of the WHO global technical strategy for malaria.
- malaria elimination
- mass drug administration
- drug resistance
- insecticide resistance
In 2016, 91 countries reported a total of 216 million cases of malaria, an increase of 5 million cases over the previous year. The estimated number of malaria deaths worldwide was 445,000, about the same number reported in 2015 . This suggests that, despite a substantial reduction in the malaria burden observed since 2010, largely attributed to the scale-up of effective control measures, including vector control interventions and treatment with efficacious antimalarial medicines, the rate of decline of both clinical cases and malaria deaths has stalled since 2014 and in some regions (the Americas mainly and marginally in the Southeast Asia, Western Pacific, and African regions) even reversed . The World Health Organization (WHO) has estimated that to meet the 2030 targets of global malaria strategy, a minimum investment of US$ 6.5 billion per year by 2020 is required . In 2016, such investment was US$ 2.7 billion, less than half of that required amount, and since 2014 in many high-burden countries, investments in malaria control have declined . The call for malaria eradication launched at the Malaria Forum in October 2007 by the Bill & Melinda Gates Foundation and then supported by the WHO, Roll Back Malaria (RBM) Partnership, and many other organizations and institutions seems to be at crossroads .
2. Components of malaria elimination strategy
The WHO currently considers malaria elimination at the national level as a continuum rather than the achievement of milestones for specific phases . It is structured in 4 components (A–D), each of them to be implemented according to the malaria transmission intensity. Component “A” consists of enhancing and optimizing vector control and case management, which includes universal access to malaria preventions, diagnosis, and treatment for at-risk populations, and once elimination has been achieved, “focalized” vector control programs rather than scaling back these activities; component “B” aims at increasing the sensitivity and specificity of surveillance to detect, characterize, and monitor all cases (individual and in foci), namely, to transform malaria surveillance into a core intervention; component “C” aims at accelerating transmission reduction in which new interventions such as mass drug administration (MDA) or new vaccines are included; and component “D” is implemented when transmission intensity is low to very low, which includes the search for the few remaining infections and any foci of ongoing transmission, clearing them with appropriate treatment and possibly additional vector control activities .
3. Resistance of
Plasmodium falciparumto anti-malaria drugs
Resistance to first-line treatments for
4. Resistance of
Anophelesmosquito vectors to insecticides
Resistance of malaria vectors to the 4 insecticide classes (pyrethroids, organochlorines, organophosphates, and carbamates) used for vector control interventions threatens malaria prevention and control efforts. Of the 76 malaria endemic countries that reported standard monitoring data from 2010 to 2016, resistance was detected in 61 countries to at least one insecticide in one malaria vector from one collection site, and 50 countries had resistance to 2 or more insecticides . Resistance to pyrethroids, insecticides used in all long-lasting insecticidal nets (LLINs), is widespread though its impact on LLIN effectiveness is unclear . There was no association between malaria disease burden and the level of resistance in a WHO-coordinated study implemented in 5 countries (Sudan, Kenya, India, Cameroon, and Benin) . However, given the complexity in measuring the impact of insecticide resistance, it is not possible to equate lack of evidence of impact with evidence for no impact .
5. Asymptomatic malaria infections and mass drug administration (MDA)
One of the major problems to achieve malaria elimination is represented by the hidden parasite reservoir in the human host. Microscopy (and rapid diagnostic tests (RDTs)) underestimates by about half the prevalence of
The antimalarial treatment administered during MDA campaigns could be complemented by single low-dose of primaquine, an 8-aminoquinoline that is able to clear mature
In conclusion, achieving universal access to standard control interventions, namely, case management, LLIN, IRS, seasonal malaria chemoprevention, and intermittent preventive treatment for pregnant women, remains a priority. It is essential to contain emerging drug resistance in malarial parasite and insecticide resistance in mosquito vector species. There is a dire need of additional new interventions to accelerate interruption of transmission. These should be evaluated and rapidly integrated within the standard control activities. Most of these should be implemented at the community level, and it will be important to actively involve the local populations to reach high coverage. Finally, political and financial supports should be maintained and even increased; current financial support is less than half of that estimated to reach the 2030 targets of the WHO global technical strategy for malaria .