Malaria, the disease as old as humanity itself, and often called as the ‘King of Diseases’, continues to haunt and taunt mankind. Known since millennia, malaria has played a major role in the history of mankind and it is often said that but for malaria, the history and geographical demarcations of our planet would have been different from what we have today. More than a century after identification of the causative parasites, and more than half a century after finding effective drugs and insecticides, it continues to wreak havoc on millions, particularly in the poorest parts of our world. Malaria is the fifth cause of death from infectious diseases worldwide (after respiratory infections, HIV/AIDS, diarrhoeal diseases, and tuberculosis) and the second in Africa, after HIV/AIDS. The dreaded disease is difficult to eradicate and its control is possible ONLY with coordinated efforts of the general public, healthcare personnel and government agencies. With global warming threatening to increase the mosquito density and the spread of other mosquito borne infections like Dengue and Chikungunya, time has come for all of us to wake up.
Malaria is an infectious disease caused by the parasites called Plasmodia. There are five identified species of this parasite causing human malaria, namely, Plasmodium vivax, P. falciparum, P. ovale, P. malariae and P. knowlesi. The infection is transmitted between humans by the female anopheles mosquito. It is a disease that can be treated in just 48 hours, yet it can cause fatal complications if the diagnosis and treatment are delayed. Despite centuries of efforts, malaria continues to infect millions and kill thousands.
Malaria transmission occurs in five of the six WHO regions, with Europe remaining free. Globally, an estimated 3.2 billion people continue to be at risk of being infected with malaria and developing disease, and 1.2 billion are at high risk (>1 in 1000 chance of getting malaria in a year). According to World Malaria Report 2018, in 2017, an estimated 219 million cases of malaria occurred worldwide, compared with 239 million cases in 2010 and 217 million cases in 2016. Although there were an estimated 20 million fewer malaria cases in 2017 than in 2010, data for the period 2015–2017 highlight that no significant progress in reducing global malaria cases was made in this timeframe. Most malaria cases in 2017 were in the WHO African Region (200 million or 92%), followed by the WHO South-East Asia Region with 5% of the cases and the WHO Eastern Mediterranean Region with 2%.
Fifteen countries in sub-Saharan Africa and India carried almost 80% of the global malaria burden. Five countries accounted for nearly half of all malaria cases worldwide: Nigeria (25%), Democratic Republic of the Congo (11%), Mozambique (5%), India (4%) and Uganda (4%). The incidence rate of malaria declined globally between 2010 and 2017, from 72 to 59 cases per 1000 population at risk. Although this represents an 18% reduction over the period, the number of cases per 1000 population at risk has stood at 59 for the past 3 years. The 10 highest burden countries in Africa reported increases in cases of malaria in 2017 compared with 2016. Of these, Nigeria, Madagascar and the Democratic Republic of the Congo had the highest estimated increases, all greater than half a million cases. In contrast, India reported 3 million fewer cases in the same period, a 24% decrease compared with 2016.
In 2017, 3.4% of all estimated cases globally were caused by P. vivax, with 56% of the vivax cases being in the WHO South-East Asia Region. P. vivax is the predominant parasite in the WHO Region of the Americas (74%), and is responsible for 37% of cases in the WHO South-East Asia Region and 31% in the WHO Eastern Mediterranean Region.[WMR, 2018] In 2016, 85% of estimated vivax malaria cases occurred in just five countries (Afghanistan, Ethiopia, India, Indonesia and Pakistan), and 51% cases occurred in India alone.
Efforts to control malaria are being strengthened, with gradual increase in funding, better diagnosis and treatment, and increased coverage of mosquito control measures and provision of insecticide treated bednets. According to WMR 2015, 57 of 106 countries that had ongoing transmission in 2000 have reduced malaria incidence by >75% and another 18 countries are estimated to have reduced malaria incidence by 50–75%. In 2016, 44 countries reported fewer than 10 000 malaria cases, up from 37 countries in 2010, and Kyrgyzstan and Sri Lanka were certified by WHO as malaria free. Also in 2016, WHO identified 21 countries with the potential to eliminate malaria by the year 2020.[WMR 2017] In endemic areas of Africa, infection prevalence among children aged 2–10 years is estimated to have declined from 33% in 2000 to 16% in 2015, with three quarters of this change occurring after 2005. Of the 15 countries with highest malaria incidence, Nigeria ranked at the top with an estimated 85 million cases,
The malaria mortality rate, which takes into account population growth, is estimated to have decreased by 60% globally between 2000 and 2015. It is estimated that a cumulative 1.2 billion fewer malaria cases and 6.2 million fewer malaria deaths occurred globally between 2001 and 2015 than would have been the case had incidence and mortality rates remained unchanged since 2000. In sub-Saharan Africa, it is estimated that malaria control interventions accounted for 70% of the 943 million fewer malaria cases occurring between 2001 and 2015, averting 663 million malaria cases. Of the 663 million cases averted due to malaria control interventions, it is estimated that 69% were averted due to use of insecticide-treated mosquito nets (ITNs), 21% due to artemisinin based combination therapy (ACT) and 10% due to indoor residual spraying (IRS).[WMR 2015]
In 2017, there were an estimated 435 000 deaths from malaria globally, compared with 451 000 estimated deaths in 2016, and 607 000 in 2010. Children aged under 5 years are the most vulnerable group affected by malaria. In 2017, they accounted for 61% (266 000) of all malaria deaths worldwide. The WHO African Region accounted for 93% of all malaria deaths in 2017. Although the WHO African Region was home to the highest number of malaria deaths in 2017, it also accounted for 88% of the 172 000 fewer global malaria deaths reported in 2017 compared with 2010. Nearly 80% of global malaria deaths in 2017 were concentrated in 17 countries in the WHO African Region and India; 7 of these countries accounted for 53% of all global malaria deaths: Nigeria (19%), Democratic Republic of the Congo (11%), Burkina Faso (6%), United Republic of Tanzania (5%), Sierra Leone (4%), Niger (4%) and India (4%).
More than 30000 cases of malaria are reported annually among travelers from developed world visiting malarious areas.[Leder K et al] With the shrinking globe, perennially prevalent malaria, therefore, remains an ever existing danger for humanity, in every part of the globe. In most areas, malaria and poverty co-exist, with the average GDP and average growth of per capita GDP in malarious countries being about one fifth of those in non-malarious countries.
Yet a lot more remains to be done and challenges are also increasing. Global financing for malaria control increased from an estimated US$ 960 million in 2005 to US$ 2.5 billion in 2014. International funding for malaria control, which accounted for 78% of malaria programme funding in 2014, decreased from US$ 2.1 billion in 2013 to US$ 1.9 billion in 2014 (i.e. by 8%), primarily due to changes in the funding arrangements of the Global Fund to Fight AIDS, Tuberculosis and Malaria. Most (82%) international funding was directed to the WHO African Region. Domestic funding for national malaria control programmes (NMCPs) was estimated to have increased by 1% between 2013 and 2014, from US$ 544 million to US$ 550 million. Spending on malaria control commodities (ACTs, ITNs, insecticides and spraying equipment for IRS, and RDTs) is estimated to have increased 40-fold over the past 11 years, from US$ 40 million in 2004 to US$ 1.6 billion in 2014, and accounted for 82% of international malaria spending in 2014. In that year, ITNs were responsible for 63% of total commodity spending, followed by ACT (25%), RDTs (9%) and IRS (3%).[WMR 2015] In 34 out of 41 high-burden countries, which rely mainly on external funding for malaria programmes, the average level of funding available per person at risk in the past 3 years (2014–2016) reduced when compared with 2011–2013. Exceptions were Democratic Republic of the Congo, Guinea, Mauritania, Mozambique, Niger, Pakistan and Senegal, which recorded increases. Among the 41 high-burden countries, overall, funding per person at risk of malaria remains below US$ 2.[WMR 2017]
Availability and accessibility of treatment for malaria need to be increased. Although, the proportion of children aged under 5 years, with P. falciparum malaria and who received an ACT, is estimated to have increased from less than 1% through 2005 to 16% in 2014, this proportion falls substantially short of the target of universal access for malaria case management, as envisaged in the GMAP. The number of ACT treatment courses procured from manufacturers increased from 11 million in 2005 to 337 million in 2014; the WHO African Region accounted for 98% of all manufacturer deliveries of ACT in 2014, with more than half of the total being doses for children. The number of ACT treatments delivered by manufacturers to the public sector in 2014 (223 million) was lower than the number delivered in 2013; likewise, NMCPs distributed 169 million treatments in 2014 through public sector facilities, approximately 20 million fewer than in 2013. [WMR 2015] According to WMR 2017, among 18 household surveys conducted in sub-Saharan Africa between 2014 and 2016, the proportion of children aged under 5 years with a fever who received any antimalarial drug was 41% (IQR: 21–49%). A majority of patients (70%) who sought treatment for malaria in the public health sector received ACTs, the most effective antimalarial drugs. Children are more likely to be given ACTs if medical care is sought at public health facilities than in the private sector.
Of the 78 countries reporting any monitoring data since 2010, 60 reported resistance to at least one insecticide in one malaria vector from one collection site, and 49 countries reported resistance to insecticides from two or more insecticide classes. Pyrethroid resistance was the most commonly reported; in 2014, three quarters of the countries monitoring this insecticide class reported resistance.
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