1. Overview
Malaria is a significant public health problem, with a high global burden. However, large regional disparities exist in the burden of malaria. In 2015, Sub-Saharan Africa alone accounted for 90% of the malaria cases and 92% of the malaria deaths worldwide(1) . Nigeria and Republic of Congo are two major African Countries contributing to the high malaria burden, as 36% of the malaria cases worldwide occurred in these two countries(2).
This large burden has led to the development and setting of several strategies and targets aimed at malaria control, and where possible its elimination. The Global Strategy for Malaria, 2016 to 2030 targets a 90% reduction in the incidence and mortality rates of malaria, as well as an elimination of malaria in 35 of its endemic countries by 2030. One of the SDG’s target indicators is to end the epidemics of AIDS, tuberculosis, malaria and other neglected tropical diseases by 2030(2).
Nigeria is currently a malaria endemic country with its entire population (186 million) at risk of contracting malaria(3), and a whopping 76% of this population at high risk 4. In 2015, Nigeria contributed about 29% of the malaria cases and 26% of the malaria deaths worldwide(2). These large figures imply that Nigeria’s success in tackling malaria control will play a large part in the actualization of the global goals.

2. Prevalence of Malaria in Nigeria
Over the years, malaria has remained one of the leading causes of death in Nigeria. In line with this, several strategic plans have been developed to control this menace. In 2014, the malaria control program began implementation of a National Malaria Strategic Plan to achieve pre-elimination status (less than 5000 cases per 100000) and reduce malaria related deaths to zero by 2020(5).
Currently, there are an estimated 33,000 malaria cases per 100,000 people, with 110, 000 of these cases resulting in mortality(4) .
2.1. Prevalence among children under 5 years old
A larger proportion of the malaria cases that resulted in mortality likely occurred among children less than 5 years old. Due to the endemic nature of malaria in Nigeria, partial immunity to malaria is acquired among older children. However, severe forms of malaria can be seen in children less than five years of age who have not yet acquired immunity. In 2015, 69% of the malaria deaths that occurred worldwide were among children aged below 5 years 1.
There has been a gradual decline in the prevalence of malaria among children in this age group over the years (from 42% in 2010 to 27% in 2015), However, malaria remains a leading cause of death among children in Nigeria(5),(6),(7) .

3. Risk factors
Poverty and Geography play significant roles in the prevalence of malaria in the country.
Malaria occurs disproportionately among the poor and places a heavy economic burden in poor countries, leading to a vicious cycle and an intricate relationship between malaria and poverty. Sub Saharan Africa which contains some of the poorest countries in the world largely contributes to the global burden of malaria(8). House types and food security are some indices of socioeconomic positions that have been reported to be associated with the incidence of malaria(9).
Geography plays a major role in the prevalence of malaria. The mosquito species found in Africa have a long lifespan and prefer to bite humans; a significant factor for the high prevalence of malaria in Africa. Furthermore, climatic conditions like rainfall, temperature and humidity affect the survival of mosquitoes, thus increasing the transmission rates of malaria(10).

3.1. Poverty
In 2015, the prevalence of malaria among children was 10 times higher among mothers in the lowest wealth quintile than in mothers at the highest wealth quintile with a prevalence of 42.9% and 4.4% respectively.

Children with mothers who had no education (an indicator of socioeconomic status), had a prevalence of malaria at 37.7% ; a prevalence that was 10 times higher in children with mothers who had earned more than a secondary education at 3.6% (5).

3.2. Malaria and Geography
In 2015, malaria was more prevalent in the North West at 37% than in the South-South region at 19%(5).

Due to the high amount of rainfall in the South-South region of Nigeria, it is expected that malaria transmission will be higher, as rainfall provide breeding sites for mosquitoes. However, several other factors like education and poverty may have played major roles in modifying the effect of climatic conditions on the prevalence of malaria in the country.

Residence also plays a major role in malaria prevalence. In 2015, the prevalence of Malaria was three times higher in rural areas at 12% than in urban areas at 36%(5). This may be attributed to poor housing conditions and low socioeconomic status of rural dwellers.

4. Malaria Prevention in Nigeria
There has been a scale up of efforts to prevent malaria transmission in Nigeria over the years. Effective malaria prevention methods identified are the use of insecticide treated mosquito nets and indoor residual spraying.
4. 1. Insecticide treated nets
4.1.1 Ownership
In 2015, 69% of households owned at least one insecticide treated net. The ownership of nets was 10% higher in rural areas than in urban areas. Majority of the households in North West Nigeria owned insecticide treated nets at 91%, unlike the South West with an ownership rate of 53%.
An inverse relationship between wealth quintile and ownership of nets can also be observed. The lowest wealth quintile had an ownership rate of 86%, and households in the highest wealth quintile had an ownership rate of 58%(5).
4.1.2 Utilisation
Despite high rates of ownership of insecticide treated nets in Nigeria, only 37% of the households in Nigeria slept under their mosquito nets in 2015. Less than half of the children aged below 5 years old (44%) slept under a mosquito net in 2015, and only half of the pregnant women slept under a mosquito net, even though they are extremely vulnerable to severe effects of malaria. Usage of mosquito nets among these vulnerable groups was highest in rural areas, North West region and among the lowest wealth quintile(5).

4.1.3. Indoor residual spraying
Indoor residual spraying involves the spraying of interior walls and ceilings of houses with a chemical to provide long lasting protection against mosquitoes. The IRS implementation programme is a relatively new programme, and is probably the reason that only 1% of households in the country were sprayed with IRS in 2015(5).

5. Diagnosis and Treatment
About 66% of children below 5 years who had a fever sought treatment or advice. This is indicative of the health seeking behavior of parents in Nigeria. However, only 13% of the children with fever had their blood drawn for testing, reflecting poor malaria diagnostic rates among children.
Only 38% of children who had fever took ACT for treatment of malaria, and a whopping 29% of children with fever took chloroquine, despite recommendations to stop treatment of malaria with chloroquine due to chloroquine resistant malaria.
Mother’s education plays a key role in the health of the child, as diagnostic and treatment rates among children increased with level of mother’s education(5).

6. Intermittent preventive treatment of Malaria in pregnant women
Living in a malaria endemic country usually results in the development of collective immunity among adults. However, pregnant women, particularly first timers are at increased risk of experiencing complications of malaria. Malaria contributes about 11% to maternal mortality, and negatively affects the health of the baby (11 & 12) .
All women are expected to receive 3 doses of sulfadoxinepyrimethamine (SP) medication during pregnancy in order to reduce the risks and complications of malaria.

In 2015, only 19% of women received 3 or more doses of SP during their last pregnancy, and 37% of women received 2 or more doses of Sp during their last pregnancy. Regional disparities existed in these rates. The percentage of women who received 2 or more doses of SP was about two times higher in urban areas than in rural areas at 50% and 30% respectively.

Furthermore, percentage of women who received SP while pregnant was two times higher in women who had attained the highest secondary education at 51% when compared to women who had no education at 25%(5).

7. Progress so far
There has been considerable progress in the control of malaria over the years.
A 61% increase in the ownership of insecticide treated nets among households was observed from 2008 to 2015.
In five years, there has been a 14% increase in the percentage of households who slept under a net.
The percentage of children who slept under a mosquito net increased from 2008 to 2015 by 38%.
In 2010, only 12% of children took ACT. However, over five years, this percentage increased to 38%.
There was a reasonable progress in the percentage of pregnant women who sleep under an insecticide treated net, with a 44% increase in percentage from 2008 to 2015.
Furthermore, there was a 32% increase in the percentage of pregnant women who took anti-malarial medication during their first pregnancy from 2008 to 2015.

However, not much progress has been reported in the use of indoor residual spraying among households, as well as the urban-rural disparities that exist in the prevalence of malaria among children(5) (NMIS, 2015).

8. Funding
Majority of the funding provided for the implementation of malaria intervention strategies in Nigeria have come from international donors. Global fund and PMI have remained the largest donors of malaria programmes in Nigeria. Global fund has committed 708 million dollars to malaria since 2008, and PMI has contributed a total of 420 million dollars since 2010. Together, they are funding malaria intervention programmes in 24 out of 36 states (13 & 14) .

9. Barriers to malaria control
With majority of the funding for malaria coming from international sources, there is an unsustainable source of income to control malaria in the country. In 2016, the global fund uncovered fraudulent activities after an audit conducted in NMEP(15) . This is indicative of the poor accountability and high corruption practices by government officials in the country.
Poverty has been associated with malaria. This could pose a barrier in the control of malaria as 80 million Nigerians are currently living in poverty(12).
A significant percentage of children still take chloroquine for malaria treatment, despite its ban. This could lead to ineffective treatment, when resistance to chloroquine occurs, leading to the transmission of the disease to susceptible individuals.

10. The way forward
Female education plays an important role in malaria control, as women who are educated are more likely to have access to the right health information as well as to health services for them and their children. It is thus essential that the fight to ensure every girl child is educated carries on.
The Nigerian government needs to ensure proper accountability of its resources and strengthen the fight to end corruption, because the journey to tackle malaria is a long and expensive one.
There is need for better control measures on the sale of chloroquine by pharmacies for malaria treatment in order to prevent chloroquine resistant malaria, as this will surely impede successes made.
Although progresses have been made, we must increase our efforts to ensure that by 2020, we can achieve the targets that we have set.

References
1. WHO Malaria factsheet. Accessed from http://www.who.int/mediacentre/factsheets/fs094/en/
2. World Malaria Report 2016. Geneva: World Health Organization; 2016. Licence: CC BY-NC-SA 3.0 IGO
3. World Malaria Report 2015. Geneva: World health Organization; 2015.
4. WHO Nigeria Malaria profile. 2015. http://www.who.int/malaria/publications/country-profiles/profile_nga_en.pdf
5. Nigerian Malaria Indicator Survey 2010
6. Nigerian Malaria Indicator Survey 2015
7. WHO Statistical profile, Nigeria. 2015. Accessed from http://www.who.int/gho/countries/nga.pdf
8. WHO Fact sheet on World Malaria report 2012. 2012. Accessed from http://www.who.int/malaria/media/world_malaria_report_2012_facts/en/
9. Tusting, Lucy S., et al. “Why is malaria associated with poverty? Findings from a cohort study in rural Uganda.” Infectious diseases of poverty 5.1 (2016): 78.
10. Minakaw, N., Sonye, G., Mogi, M., Githeko, A., and Yan, G. (2002). The effects of climate factors on the distribution and abundance of malaria vectors in Kenya. J. Med. Entomol., 39: 833-841.).
11. http://www.prb.org/Publications/Articles/2001/MalariaContinuestoThreatenPregnantWomenandChildren.aspx
12. Nigeria Malaria fact sheet. United State Embassy. Accessible from http://photos.state.gov/libraries/nigeria/487468/pdfs/DecemberMalariaFactSheet%202.pdf
13. PMI Nigeria Malaria Operational plan FY 2017. (2016). https://www.pmi.gov/docs/default-source/default-document-library/malaria-operational-plans/fy17/fy-2017-nigeria-malaria-operational-plan.pdf?sfvrsn=6
14. US PMI Nigeria Malaria profile. 2016. Assessed from https://www.pmi.gov/docs/default-source/default-document-library/country-profiles/nigeria_profile.pdf?sfvrsn=18
15. Global fund. Message from the executive director, Nigeria reports. Accessed from http://www.theglobalfund.org/en/oig/updates/2016-05-03_Message_from_the_Executive_Director_Nigeria_Reports/