Malaria and the cruel calculus of poverty

Take a look at this world map of malaria prevalence. The green areas show regions where malaria used to exist and no longer does; the red, countries where malaria is still a big problem:

Two things stand out about the countries where malaria remains endemic: they are all places where poverty also remains endemic; and they are clustered in a zone straddling the equator, a part of the world well known for its warm and wet climate. This post will examine how climate and poverty influence malaria prevalence.

Climate

Mosquitoes love water. Even tiny puddles, if they last long enough, can provide the perfect environment for mosquito eggs to hatch, and for the development of larvae and pupae into adult mosquitoes. More mosquitoes mean more vectors for malaria transmission.

Malaria loves warmth. The parasite completes half of its growth cycle (the “extrinsic” cycle) within mosquitoes, and it does so faster in warmer climates. Below 15 degrees C malaria cannot be transmitted because this extrinsic cycle cannot be completed.

Clearly climate matters. But look at all the green countries: their climate was suitable enough for malaria in the past, but they are now free of the disease. There are also countries like Singapore (perhaps too small to be visible on the map) which do sit in the optimal climatic zone, but have also conquered malaria. Contra Donald Trump, human beings are changing the climate, but obviously it wasn’t a change in the climate that lead to malaria eradication.

Poverty

One glance at a map showing the global distribution of poverty tells us that malaria is strongly correlated with poverty. Let’s take a look at why.

Infrastructure

Economic underdevelopment means that infrastructure is poorly developed or non-existant, which means breeding grounds for mosquitoes perpetuate in areas that humans live and work. It also means a greater proportion of the population are working in malarious environments: in Lao and the Philippines, farmers supplement their income by working in nearby forests, which is known to increase risk of contracting malaria.

Perhaps it goes without saying, but desperately poor people lack the financial means to relocate away from mosquito-friendly environments or to modify their local environment to reduce/eliminate mosquitoes. Its not simply a distinction between rural and urban but about wealth and living standards: peri-urban slums can be just as malarious as the rural agricultural village.

Education

People living in poverty are likely to have low levels of education, which makes it difficult to acquire knowledge about the causes of malaria, how to prevent it, and how to treat it. They may have very limited access to information (ever tried setting up an internet connection with no electricity?), or they may not have the literacy level to be able to comprehend malaria education material.

The calculus of poverty

Even when people are sufficiently educated about malaria, the logic of poverty itself can impose decisions on families that perpetuate malaria. An ethnographic study of rural poor in Malawi found people knowledgeable about malaria prevention and treatment, but poverty forced by poverty to make decisions that left them open to infection:

“Once the net is in the house the question arises about who is going to use it. A single mother with three small children had chosen to use the bed net herself and let the children sleep without one. Her decision was made out of consideration for the whole family… Fishermen using the bed nets for fishing were also observed during the stay in villages near the lake. A similar explanation was given by them: what use is it to avoid malaria if the family is starving?”

Prevention/treatment

Preventive measures like bed nets and insecticides are more expensive in rural than urban areas; those living in dire poverty can’t afford them, and may not have access to them in any case. They also can’t afford medication to treat malaria and probably live in areas with very little access to treatment facilities. If infection isn’t treated, then the infected person serves as a reservoir of the parasite for transmission to others. From the same study in Malawi:

“The mother of a 13-year- old girl told that her daughter had developed normally up to the age of five when she got cerebral malaria. The family lives in a village one day’s walk from a health facility. The mother had hesitated to seek help, thinking the daughter would recover, but as she got worse the mother carried her to the health clinic. When they arrived at the health clinic the daughter was critically ill. When the daughter recovered she had lost her hearing ability and could no longer walk properly.”

Malaria entrenches poverty

We have seen the range of ways that malaria is a product of poverty, but possibly the cruellest aspect of the situation is that the relationship runs both ways. As the end of the last quote hints, if you live in poverty you are likely to suffer more severely from the disease, developing cerebral malaria, dying, or suffering lifelong disability. If you are already desperately poor, death or lifelong disability of a family member will help trap you in poverty. In rural populations the time of highest malaria risk often coincides with planting and harvest: contracting malaria during these times can reduce your earning potential leaving you less able to afford to protect yourself from malaria. The cycle goes on.

References:

1. Centers for Disease Control and Prevention (US). Ecology of Malaria [Internet]. Atlanta, Georgia: Centers for Disease Control and Prevention; 2015 [cited 2017 February 25]. Available from: https://www.cdc.gov/malaria/about/biology/ecology.html

2. Max Roser. Malaria [Internet]. Oxford, England: Our World in Data; 2016 [cited 2017 February 25]. Available from: https://ourworldindata.org/malaria

3. Actualitix. Population Below Poverty Line (%) [Internet]. 2017 [cited 2017 February 25]. Available from: http://en.actualitix.com/country/wld/population-below-poverty-line.php

4. Health and Environment Linkages Initiative. Malaria control: the power of integrated action [Internet]. World Health Organisation; 2017 [cited 2017 February 25]. Available from: http://www.who.int/heli/risks/vectors/malariacontrol/en/index2.html

5. Ricci F. Social implications of malaria and their relationships with poverty. Mediterranean Journal of Hematology and Infectious Diseases [Internet]. 2012 [cited 2017 February 25]; 4: 1 [about 10 pages]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435125/

6. Ingstad B, Munthali AC, Braathen SH, Grut L. The evil circle of poverty: a qualitative study of malaria and disability. Malaria Journal [Internet]. 2016 [cited 2017 February 25]; 11:15. Available from http://malariajournal.biomedcentral.com/articles/10.1186/1475-2875-11-15

7. Teklehaimanot A, Mejia P. Malaria and Poverty. Annals of the New York Academy of Science [Internet]. 2008 [cited 2017 February 27]; 1136:32–37. Available from: https://www.ncbi.nlm.nih.gov/pubmed/18579874