Malaria is one of the deadliest infectious diseases known to humankind, killing around 400,000 people every year. And while great strides have been made in recent years in prevention and treatment, especially in Asia, eliminating the disease entirely remains a major challenge.
According to the latest global estimates by the World Health Organization (WHO), around 219 million malaria cases were reported in 2017 compared with 217 million in 2016 and 239 million in 2010. The disease killed 435,000 people in 2017, largely in Africa, with children under age five making up 61% of the total.
Southeast Asia ranked second globally with 11 million or 5% of all reported cases, against 200 million or 92% in Africa. Fifteen countries in sub-Saharan Africa and India accounted for almost 80% of the global malaria burden. Five of those accounted for nearly half of all cases worldwide: Nigeria (25%), Congo (11%), Mozambique (5%), India and Uganda (4% each).
In terms of outbreaks, India reported 3 million fewer cases in 2017, a 24% decrease from 2016. Pakistan also saw improvement with 240,000 fewer cases. But increases were seen in the 10 highest-prevalence countries in Africa, suggesting the battle ahead will be a long one.
Southeast Asia continued to see its incidence rate fall, from 17 cases per thousand population at risk in 2010, to 7 in 2017, a 59% decrease. In the same period, the global incidence rate declined from 72 to 59 per thousand population at risk.
The number of countries nearing elimination -- defined by the WHO as no new cases for three consecutive years -- reached 46 in 2017, compared with 37 in 2010. In China, where malaria had long been endemic, no local transmission was reported in 2017. The WHO calls this "proof that intensive, country-led control efforts can succeed in reducing the risk people face from the disease".
With China eliminating the disease and India managing the biggest drop in cases, it could be viewed that the malaria problem in Asia is dissipating. However, experts warn that the monumental progress made in the last 20 years might lead us to drop our guard at the most crucial point, which is right now.
"Although there were an estimated 20 million fewer malaria cases in 2017 than in 2010, data for the period 2015-17 highlight the fact that no significant progress in reducing global malaria cases was made in this timeframe," the WHO World Malaria Report noted. There are also reports of growing resistance to anti-malarial drugs and insecticides in Southeast Asia.
DRUG RESISTANCE
A child still dies every two minutes because of malaria, according to the Malaria Futures for Asia (MalaFA) report commissioned by Novartis Social Business. The multinational pharmaceutical company introduced the world's first fixed-dose artemisinin-based combination therapy (ACT) two decades ago and it is still the most accepted anti-malarial treatment.
Citing the 2017 and 2018 World Malaria Reports, the study released in April said that following the unprecedented success of global malaria control in recent years, progress had now "stalled" and global donor money had "flatlined" in recent years. It also noted new threats such as resistance to ACTs.
"This is the first time in many years that Asian policymakers and implementers on the ground have been asked about their views on progress, challenges and opportunities toward malaria elimination," said Prof Yongyuth Yuthavong, a former deputy prime minister of Thailand and a member of the board of the RBM (Roll Back Malaria) Partnership to End Malaria and co-chair of the study.
"Complacency is always a danger. I have spent a lifetime fighting malaria and know that this final stage toward elimination will be the toughest" — PROF YON GYUTH YUTHAVONG, RBM Partnership to End Malaria
The MalaFa report, developed in consultation with several organisations dedicated to fighting malaria, involved 36 interviews with malaria programme directors, researchers and NGOs in Cambodia, India, Myanmar, Thailand and Vietnam on progress toward malaria elimination.
"While most are confident about progress, some are perhaps too confident. Complacency is always a danger. I have spent a lifetime fighting malaria and know that this final stage toward elimination will be the toughest," Prof Yongyuth said at the launch of the report in Bangkok.
Nearly two-thirds of the respondents believe that Southeast Asia is likely to meet its malaria elimination targets for Plasmodium falciparum malaria, the most severe form of the disease.
However, a majority expressed scepticism that the P. vivax strain could be eliminated by 2030, which is one of the WHO's targets.
P. falciparum is the most prevalent malaria parasite, accounting for 99.7% of cases in 2017 in Africa, 62.8% in Southeast Asia, 69% in the Eastern Mediterranean and 71.9% in the Western Pacific. P. vivax is the predominant parasite in the Americas, representing 74.1% of cases there.
"The problem with malaria in Asia right now also occurs within the IT system, which we call the last-mile problem," Prof Yongyuth told Asia Focus. "This is where the main system might be functioning but the connection hasn't reached your house yet, and malaria is the same.
"When there are only few cases left, it is hard to find them and if the system is no longer well supported, the disease could gradually make a comeback."
In Sri Lanka, for example, malaria was almost -- but not quite -- eradicated 30 years ago. The disease made a comeback before being fully eliminated more recently, he said.
And while the number of reported cases in Thailand has fallen to about 10,000 a year from 100,000 in the past, Prof Yongyuth says increased migration is now a "huge problem", especially from drug-resistant malaria cases via countries such as Cambodia, Laos, Myanmar and Vietnam.
"The Thai government is aiming to end malaria by 2024 but the drug-resistant cases from neighbouring countries will make this effort harder to achieve," he said.
One-third of the participants in the MalaFA survey have expressed deep concern about more drug-resistant cases being reported in the region, said Prof Yongyuth, who served as Minister of Science and Technology from 2006-08 and now heads a research group on anti-malarials at the National Center for Genetic Engineering and Biotechnology (Biotec).
"Around one-third of them say they are very worried that if there are more drug-resistant cases, we will not be able to find a new [drug]," he said. "However, around one-third of them also say that such cases have been reported since 10 years ago. 'Yes, there are more drug-resistant cases being reported but it is not rapidly widespread,' they say, while another one-third do not see the problem at all."
Students in the border provinces of Mae Hong Son, Tak and Trat join a field activity designed to educate them about mosquitoes as carriers of malaria, the danger they pose and how mosquito larvae can be exterminated. (Photo courtesy of the Kenan Institute Asia)
Prof Yongyuth says those experts who believe drug resistance is not a big problem have pointed out that most such cases stem from the treatment method.
"The reason why we can effectively cure malaria now is because we are not using only one drug but a mixture of them, and some experts say the majority of the drug-resistant cases are from the coupling of these drugs," he said.
One way to stop the spread of resistance to anti-malarial drugs and insecticides is China's "1-3-7" surveillance and response strategy. Introduced in 2012, it is a simplified set of targets that delineates responsibilities, actions and their time-frame.
The strategy has been a key factor in helping China reach zero locally transmitted malaria cases in 2017, according to the Asia Pacific Malaria Elimination Network. It has now been modified and adopted by Cambodia, Indonesia and Thailand.
In China, any confirmed and suspected malaria cases by law must be reported to the web-based health information system within 24 hours of diagnosis by the local healthcare provider. All cases should then be confirmed and visited by the county-level Chinese Centre for Disease Control and Prevention (China CDC) where the case is reported within three days, to determine where it originated (local or imported).
Lastly, the investigation must be conducted as soon as possible. If local transmission is possible or confirmed, targeted action to seek out other infections and reduce the chance of onward transmission is completed within seven days by the county-level CDC where the patient resides or works.
"Thailand is strict with our protocols but if our neighbouring countries are not and there is ongoing migration, this is where the problem becomes more complicated," he said.
FALLING FUNDING
Prof Yongyuth says Asean should collaborate more against malaria as some countries in the region cannot afford to fight the last-mile battle on their own, while global funding is also declining.
According to the WHO, as reductions in malaria cases and deaths slow, funding for the global response has also been levelling off, with US$3.1 billion made available for control and elimination programmes in 2017, including $900 million or around 28% coming from governments of malaria-endemic countries.
The US remains the largest international donor, contributing $1.2 billion (39%) in 2017. However, to meet the 2030 targets of the global malaria strategy, investments should reach at least $6.6 billion annually by 2020, more than double the amount available today, the WHO says.
The organisation last year introduced a new country-driven "high burden to high impact" response plan to support nations with most malaria cases and deaths. It has four pillars: galvanising national and global political attention to reduce malaria deaths; driving impact through the strategic use of information; establishing best global guidance, policies and strategies suitable for malaria-endemic countries; and carrying out a coordinated country response.
The new plan was an acknowledgement that an earlier WHO goal to reduce malaria incidence and death rates by at least 40% by 2020 would not be met.
"Some countries have been receiving global funding but reported no results in the end which led to the current reluctance from some donors," Prof Yongyuth said. "Now we all have to depend on ourselves even more. We have to stop saying that 'if you do not help us, we won't do anything' because it is no longer possible."
Thailand next year will cease to be a recipient of global funding from donor countries and private funds such as the Bill & Melinda Gates Foundation, which last year pledged to invest $1 billion through 2023 to fund research and development efforts to end malaria.
"From my talks with the current authorities in the country, I am happy that Thailand should be able to depend on ourselves from now on," said Prof Yongyuth.
Deborah Gildea, head of Novartis Social Business Asia, told Asia Focus that regional collaboration to educate the public and stop malaria from spreading is still needed to respond to outbreaks and drug-resistant cases.
"We are beginning to see (drug-resistant cases), not only in Cambodia, but in neighbouring countries such as Laos as well," she said. "It is still relatively small -- so far nobody has not responded at all [to the drugs] -- but we are seeing that the response rate to ACT is becoming longer, which is an initial signal of growing resistance."
She says the resistance problem currently occurs only with the P. falciparum parasite, which accounts for 60% of infections in Asean, while P. vivax accounts for the rest. As cases of P. falciparum continue to decline, P. vivax cases will be more prevalent but the absolute numbers are growing smaller, which is "very encouraging".
Asked if a new kind of drug is needed to combat the resistance problem, Ms Gildea said the consensus in the MalaFA study was that if Asean and India continue to focus on collaboration, it is "possible to eliminate P. falciparum before resistance becomes a big problem here in Southeast Asia".
"It is all about being very objective about who the populations are that need to be reached and who are they most comfortable to be treated by," she explained.
"If you are a migrant worker, you might not be comfortable with going to the local health centre. You might be more comfortable getting help from an NGO or some of the monks in the rural community."
Once these preferred helpers for migrant workers have been identified, government and private sources should then move to fund and equip them with the right medicines and diagnostic tools to ensure patients receive the right treatment.
"It is not necessarily about more money, it is about putting efforts into the right places with the right organisations who can connect well with those patients," said Ms Gildea.
