Despite Nigeria’s high malaria burden, Professor Olugbenga Mokuolu, a malaria expert and former National Malaria Technical Director, in this interview by SADE OGUNTOLA says it is not all gloom as over 208 million cases and 2.6 million deaths were averted over the last two decades in the country.
THE Nigerian Institute for Medical Research (NIMR) recently reported on the identification of a new malaria vector called Anopheles Stephensi in northern Nigeria. What is the implication of this newly discovered vector on malaria elimination in Nigeria?
Anopheles Stephensi is a recently discovered mosquito specie of the anopheles group of mosquitoes. Malaria is transmitted by the female anopheles mosquito. There are different species of the female anopheles mosquito that we already know, but the A. Stephensi is indeed a more recent addition. It has been reported to be associated with intense transmission of malaria, thereby posing a significant threat to the gains in the fight against malaria. It is said to be more common where they keep animals.
As reported by NIMR, this specie of the anopheles mosquito was identified among a pool of mosquitoes that were collected from different parts of the country over two years ago. It has subtle but unique characteristics in its physical appearance that required very diligent and detailed analysis to come to the conclusion that it was indeed Anopheles Stephensi. Imagine trying to see if one housefly is different from another housefly (yet houseflies are much bigger than mosquitoes).
The National Malaria Elimination Programme (NMEP) together with NIMR and with support from malaria partners are reviewing more samples collected from different parts of the country to identify the extent of its distribution and to find out if it has had an implication on the burden of malaria in Nigeria. But currently we are not seeing immediate signals that would have been said to be attributed to the presence of that vector, as reported from other countries. The COVID-19 experience continues to be a good reminder of the local context of various diseases.
What are Nigeria’s achievements on malaria control?
First, we can consider malaria prevalence, which is the proportion of people in the population that have the malaria parasite, particularly in children aged 6-59 months. In 2010, malaria prevalence was 42 percent in Nigeria; it went down to 27 percent and 23 percent respectively by 2015 and 2018. In 2021, malaria prevalence was 22 percent. So, in Nigeria, over a decade, malaria prevalence reduced by at least a half. That is one way of measuring progress.
Secondly, over the last two decades, 208 million malaria cases were averted. That means that between 2000 and 2020, efforts to control malaria in Nigeria averted 13 percent of the global cases of the disease. In addition, 2.6 million deaths due to malaria were averted over the last two decades in Nigeria. It would have been a contribution of 25 percent of the global deaths. The global deaths due to malaria are put at about 7.6 million. Now, any old document describing malaria in Nigeria will tell you that if you take children under 10, malaria will be identified in 75 percent of them (this was called holoendemicity). But the level of malaria has come down to between 25 and 40 percent (Mesoendemicity).
As we speak, the incidence of malaria has declined significantly in Lagos. In fact, Lagos has the lowest burden of malaria in Nigeria with a prevalence of about two percent, and there has not been any net campaign in that state in the last seven years. Due to the substantial progress, Lagos has technically entered what we call the pre-elimination stage. This does not mean fewer challenges; rather, it implies adjustment of strategies to respond to this level, which could be very engaging especially against the backdrop of the movement of people in and out of Lagos. Even in the North-East and North-West, the burden of malaria used to be over 60 percent, it has come down to about 40 percent.
Are there challenges to ensuring zero malaria cases in Nigeria?
Malaria is an interaction between man, mosquito, environment, and the parasite itself. It is four-way traffic. So, when you talk about challenges, we have an environment that supports the thriving of the vector itself. The mosquito that carries the parasite does well in an environment that is warm, and Nigeria is warm all year round. We also have the challenge of poor environmental management; we have ghettos, urban slums and blocked drainages that ensure stagnant water is always around for mosquitoes to breed.
In one of our major cities, while tracking severe malaria over a three-year period, 97 percent of the cases were in the communities on the left side of the rail line that passes through the town. The right side of the rail line, which was the government reserved area in the town and with good roads, good housing, and well laid out environment, recorded no severe malaria cases. Studies on environmental determinants of malaria showed a 30 percent contribution from the environment to the burden of malaria. So, when we are not developing our societies, the fight against malaria will be hindered.
What has helped the other developed nations? They have a natural habitat that was not the best, but malaria still occurred there. Most of what we know about malaria started from Italy; it is not from Nigeria. But whereas their environment made the progress of malaria to be slow, they gave it the punch by developing their environment. This is unlike our own situation where the environment is naturally favourable and the development is slow. So, naturally, malaria is going to have the upper hand. This is without prejudice to the effort and efficiency of whatever it is that we are deploying to control malaria. That is why a little slack in our intervention efforts creates a scenario where malaria simply goes back to its previous level or higher. All these are preliminary challenges.
Now, there are challenges with regard to adequacy of coverage of interventions used to control malaria. Until recently, we had no resources to deploy nets and malaria treatment commodities to 13 states out of the 37 states over the last five years. The Federal Government has however now secured a $300 million facility to support the scope of malaria interventions in those 13 states. Technically speaking, we should now be able to implement our interventions to a significant degree in all states over the next three years. We hope there will be a major effect on malaria fight as we improve coverage.
With regard to malaria prevention in pregnancy, where women ought to be using an extremely cheap medicine called sulfadoxine-pyrimethamine (SP), we have also experienced significant challenges because we are not able to carry out a central procurement or put in place sustainable systems. Generally, the government makes promises to procure this drug. Sometimes with advocacy, you see the states procuring some part of it. And to further address it, some states now had to bring up the drug revolving fund so that at least people can have access to the drug, even if it is not going to be free. Of course, the next challenge is ensuring pregnant women get to the health facilities in the first instance.
So, why then is Nigeria still quoted as contributing the highest number of malaria cases globally?
We can contribute the highest number but what is the total number of global malaria cases? Previous reports indicated that over 500 million malaria cases occur annually in the world and Nigeria contributes significantly to that number. Now, we will say that about 240 million malaria cases occur annually and Nigeria is contributing about a quarter of that. So, Nigeria, while being responsible for the highest number of cases, has also contributed to the highest numbers in case reduction. Overall, numbers are reducing. It is difficult for Nigeria to rapidly overtake every other country because they share similarities in their current drivers of malaria burden. If we are to change our position, it means that we must do a few things more drastically.
What must Nigeria do more drastically to change its position?
First, we should face development squarely; we must think outside of the box to ensure fast development. Ten countries in Africa are responsible for 80 percent of the malaria in the world. Malaria control and elimination require a multi-sectoral collaboration. Malaria is not just a disease for the health sector; it is an economic burden and a national malady.
Two, we have, for very long, relied on donor efforts; their contributions are useful and well appreciated. But if malaria is a problem that it is, then our government also needs to commit to malaria, the way we were committed to COVID-19. We did not leave COVID-19 to donors; everybody stood up. Malaria is not just a business for the government; it is everybody’s business to ensure the interruption of the spread of malaria parasites. We need a stronger political will demonstrated by clear commitment to the fight against malaria as expressed by fund allocation and release to ensure full coverage of all malaria interventions to all eligible populations.
Also, Nigeria should accelerate access to malaria vaccines. Its approval for use in Nigeria is a good one. There are two of such vaccines; the RTSS vaccine was tried in Ghana, Malawi and Kenya, and a second malaria vaccine developed by Oxford University is just completing phase III clinical trials. For now, we should be embracing these vaccines to expand access to malaria prevention. We should play an active role as a country to help gather the needed data to support the development and deployment of the malaria vaccines. They hold the potential for enhancing the fight against malaria. Just imagine the use of RTSS, for instance; it will help to reduce deaths by 40 percent. Certainly, the adoption of the vaccine will dent the malaria burden landscape.
We do need more options like the malaria vaccine that is less dependent on people’s behaviour in controlling malaria. It is easier to convince somebody to go to the health facility to take one dose of the vaccine and subsequent doses than to convince the people to sleep under the net every single day. These options will not displace other malaria prevention interventions, but they will remain complementary in terms of what we are doing.
Antimalarial drug resistance remains a concern globally. To what extent is that a problem in Nigeria?
This is a global concern that has been fully documented in Asia in areas like Thailand. Artemisinin combination therapies (ACTs) are currently the drugs for the treatment of malaria. In Africa, Rwanda and Uganda have reported partial artemisinin-resistance. But evidence from very robust therapeutic efficacy studies conducted annually in Nigeria still shows that we do not have artemisinin-resistance yet in Nigeria. So, the ACTs recommended for treatment of uncomplicated malaria remains valid. However, we are not resting there. Nigeria is participating in studies that will provide alternatives to the ACTs. One such study is the development of triple artemisinin combination therapies TACTs.
What are your concluding thoughts?
Consistent with the theme of the World Malaria Day celebrations, it is indeed time to bring malaria down to zero. We must go beyond the rhetoric and demonstrate the political will through commitment to investments, innovations, and implementation of bold initiatives. We need stronger partnerships, multisectoral collaboration, private sector engagements and health system strengthening.
and then