Why mainland still lags behind Zanzibar on malaria
What you need to know:
- As the fight against malaria continues, the Ifakara Health Institute highlights areas that have affected the mainland’s fight, unlike Zanzibar which has seen success in curbing the disease
In most malaria-endemic countries, four interventions—case management (diagnosis and treatment), insecticide-treated bed nets (ITNs), intermittent preventive treatment of malaria during pregnancy (IPTp), and indoor residual spraying (IRS)—make up the essential package of malaria interventions.
Between 2001 and 2015, a substantial expansion of these interventions contributed to a 30 percent reduction of the global incidence of malaria and a 47 percent decline in malaria mortality rates.
Are we winning the war on malaria?
Dr Fredros Okumu, a parasitologist and entomologist, who currently works as director of science at the Ifakara Health Institute (IHI), argues that we are not.
The fact of the matter is that right now, the progress the world has been making against malaria has stalled even as new tools and treatments were developed and ambitious ideas like gene drive advanced through clinical research.
“To put it outrightly, we are losing this war,” he says.
His basis for arguing this is because of the burgeoning population in Africa.
“Overall, the economic and public health burden is higher than it used to be because of population growth coupled with expensive preventive and curative methods.”
“While the successes of the past few years have certainly narrowed the number of cases and deaths attributed to malaria, stagnating financial support, weak health systems, lack of adequate domestic financing and multi-sectoral approaches, emerging resistance to front-line treatments for severe malaria in Africa, and climate change are among key challenges that continue to plague the fight against the disease,” notes Dr Okumu.
Halfan Ngowo, a research scientist also at the IHI says that looking at a 10-year period, malaria cases seem to be have been declining with the introduction of new tools like the new malaria vaccines, indoor residual spraying, and insecticide treatment.
“We have the largest mosquito insectary facility capable of carrying out any research question,” noted Arnold Mmbando, a research scientist at the same institute.
Why malaria still runs rampant on the mainland
In most countries where malaria is endemic, the disease disproportionately affects people experiencing disadvantage, poverty, and exclusion, who have limited access to health facilities and can barely afford the recommended treatment.
Too many people are still missing out on the malaria interventions they need, and more than half the world’s population is still unable to access health services without incurring financial hardship.
“Most malaria-infected people who receive treatment in good time are fully cured and suffer no long-term effects. However, a minority can be unresponsive to standard treatments. In the case of Africa, most of the cases reported are in rural settings where health systems are weak. This means that if a person experiences fever and flu-like illness they will not go to a clinic immediately. They will delay, take over-the-counter medications and wait out the symptoms. This delay automatically reduces the efficacy of treatment and therefore the outcome is poor,” Dr Okumu says.
Covid-19’s disruption
New data from the WHO also reveals that the Covid-19 pandemic has disrupted malaria services, leading to a marked increase in cases and deaths. In recent years, the Director of the WHO Global Malaria Programme Dr Pedro Alonso said, forward momentum levelled off.
By 2017, the case incidence rate ticked upward, and the decline in the mortality rate had stalled.
“Of particular concern are the reversals in progress that we are seeing in countries hit hardest by malaria. We are substantially off track in our efforts to achieve the malaria targets of the WHO global strategy,” wrote Dr Alonso.
“Here in Ifakara everything but essential work stopped working due to the pandemic. Given the ongoing pandemic, there were significant delays in supply and delivery of bed nets,” explains Ngowo.
“Applying a new cause-of-death methodology revealed that malaria has taken a considerably higher toll on African children every year since 2000 than previously thought,” says the WHO World Malaria Report.
Drug resistance
Drug resistance to antimalarials and insecticides used on bed nets and indoor/outdoor residual spraying has emerged as one of the greatest challenges facing malaria control today.
It has been implicated in the spread of malaria to new areas and the re-emergence of the disease in areas where it had been eradicated. Resistance occurs when the effectiveness of a drug is reduced and it no longer provides a full cure against the targeted infection.
Reports of sporadic resistance to modern malaria drugs have begun appearing in recent years and are now confirmed in Rwanda and Uganda.
“Resistance is something we should worry about because it will be difficult to take care of young children and pregnant women who are the majority of the population at risk of developing severe malaria,” explains Ngowo.
An even bigger problem was the lack of real-time data on the extent, impact, and magnitude of drug resistance.
Resistance to chloroquine was once considered to be the magic bullet against malaria. But malaria parasites evolved to survive it prompting the WHO and African governments to switch to artemisinin combination therapy (ACTs).
Because the ACTs are mixtures, Dr Okumu explains, it is difficult for malaria parasites to resist them. However, soon after the introduction of the drugs, reports of resistance to artemisinin started to emerge.
Scientists and health practitioners now are increasingly concerned that the situation may worsen in the years to come. Front-line drugs remain largely effective, but the likelihood of widespread failure is growing fast.
“The good news is that resistance to artemisinin has not spread widely in Africa. African malaria parasites already have the genetic changes potentially associated with resistance to artemisinin. But the frequency of these changes is still very low,” says Dr Okumu.
Climate change and urbanisation
Climate change has also seen mosquitoes change their behaviour. Long considered a rural disease, scientists in 2020 showed that malaria cases are increasing among city dwellers following the invasion of a new species of mosquito from Asia.
Malaria has largely been defined as a rural disease where the species known as Anopheles gambiae thrives.
However, ongoing urbanisation has meant that many cities have developed areas for urban agriculture.
This, combined with poor water management, unplanned urban sprawl, and an emerging adaptation to dirtier water, means there are increasingly more environments for mosquitoes to breed.
This has led to a rise in malaria transmission in many African cities.
In recent years, an invasive vector species, known as Anopheles stephensi that adapts easily in urban environments has been extending its range in East Africa, with detections reported across Djibouti, Ethiopia, Somalia, and Sudan.
The species was first discovered in 2012 following an unusual outbreak of malaria in Djibouti.
“By combining data for Anopheles stephensi across its full range (Asia, Arabian Peninsula, Horn of Africa) with spatial models that identify the species’ preferred habitat, our results suggest over 126 million people in cities across Africa could be at risk,” the researchers said.
So, can we eradicate malaria?
On scientific grounds, eradicating malaria is complex and difficult. To begin with, there are four species of human malaria.
The two most common are Plasmodium falciparum (P. falciparum) and Plasmodium vivax (P. vivax), with the former being the most dangerous of the four species, causing the vast majority of malaria deaths, particularly in Sub-Saharan Africa.
The discovery and use of DDT, a powerful insecticide saw the US eradicate malaria by 1951 but in Latin and South America pockets recurred two decades later.
Today 40 countries and territories globally have been granted a malaria-free certification from WHO – including, most recently, China and El Salvador (2021), Algeria (2019), Argentina (2019), Paraguay (2018), and Uzbekistan (2018).
“It is hard to replicate the interventions the US and Europe made because the mosquito species prevalent in Africa is not the same as the ones in the west. The species in Africa are predominantly human dependent, meaning that they feed on human blood,” notes Dr Okumu.
But scientists say there’s no reason the world can’t do it altogether.
“There is rapid urbanisation, mass outdoor residual spraying of swampy places, use of spatial repellents are volatile chemicals that prevent biting by mosquitoes, and now the introduction of a malaria vaccine are some of the things that can help rid of mosquitoes,” says Halfan Ngowo.
In the last few years in the use of gene-editing techniques for safe, ecologically responsible pest control.
New drugs have been developed and found to be effective.
Studies have seen good results for the mass administration of antimalarial drugs.
In October 2021, WHO made a historic announcement: for the first time, the World Health Organisation (WHO) recommended the broad use of a vaccine for children aged six weeks to 17 months living in sub-Saharan Africa and in other regions with moderate to high Plasmodium falciparum.
The approval was based on a review of evidence on the RTS,S vaccine.
To date, the pilot programme has shown that the vaccine is safe, has a substantial public health impact, and is highly cost-effective.
It is the largest implementation study that WHO has ever undertaken.
“If introduced widely, we estimate that the RTS,S vaccine could save between 40,000 and 80,000 young lives every year – but only if it’s given a chance to work,” wrote Dr Pedro Alonso, director, WHO global malaria programme in a letter to malaria partners (December 2021).
