Illustrated by Julia Dingman

Malaria Moves Back West: Climate Change and Colonization in Biotechnologies for “Tropical” Disease

Kaz Nuckowski | SQ 2023-2024


Transmitted by female biting anopheles mosquitoes carrying the plasmodium parasite,[1] malaria thrives in the heat. It kills over 600,000 people annually, and more than half of all malaria deaths occur in just four sub-Saharan African countries.[2] With climate models predicting a lengthening of the malaria season[3] and insecticide resistance becoming more widespread,[4] new solutions are required. Preventing malaria in Africa remains challenging because of sparse public health infrastructure. Biologists at UC San Diego have joined the research trend reimagining malaria prevention using novel genetic biotechnology.

Gene Drives and Iphigenia

Gene drives make use of CRISPR to create “selfish genes” which conserve themselves in offspring.[5] One gene drive model, the “suppression drive,” forces deleterious traits into a population — akin to genetic insecticide.[5] Dr. Andrea Smidler’s team followed a suppression approach to create ifegenia: inherited female elimination by genetically encoded nucleuses to interrupt alleles. Named for the sacrificed daughter Iphigenia of Greek mythos, this technology knocks out the femaleless gene — necessary for female mosquito development — to cause female death.[6]

Importantly and interestingly, ifegenia is not a gene drive. In contrast to gene drives’ 100% heritability, ifegenia follows classical Mendelian inheritance patterns (Figure 1).[7] This renders ifegenia resource-intensive, as multiple releases are required for suppression.[7] However, this weakness can also be a strength. “You can’t control where a mosquito goes, so you can’t control where a gene drive goes,” Dr. Smidler notes. This makes gene drives “unconfinable,” in contrast with ifegenia.[7] “It doesn’t cross borders, which is a big point of contention among African nations.”[7] When considering antimalarial biotechnologies, we must weigh the politics of their implementation.

The Role of Local Stakeholders

Disease control programs that don’t involve local stakeholders are usually ineffective. The failure of the Global Malaria Eradication Program (GMEP) serves as one example. The program was created in 1955 by the WHO, spurned by the elimination of malaria from the US a few years prior.[8] The GMEP’s aggressive implementation of only insecticide spraying contributed to its discontinuation just 14 years later. The sub-Saharan African countries home to the majority of malaria cases did not have adequate public health infrastructures to support spraying. Perhaps more problematically, they were not consulted on the program’s feasibility.[8] In the context of disease control, it’s important to consider colonial histories of paternalism and othering in tropical medicine.

Tropicality and Malaria

Malaria is typically described as a “tropical” disease. But malaria was present in the US until the early 1950s.[8] Tropicality embroils discussions of malaria in environmental determinism, where non-temperate climates and their inhabitants are painted as inherently unhealthy or extreme harbors of disease.[8] As a field, tropical medicine was developed as a colonial tool to create dependence in African and Asian subjects of empire.[8] Accordingly, it is not climate which makes the global South vulnerable to malaria. Robust public health systems enabled American elimination in the 1950s — and colonialism impeded the development of infrastructures to do the same in sub-Saharan Africa.[9]

Gene Drive Technology and its Implications

Popular discussions of gene drive technology can reinforce the concept of “tropical” disease. NPR articles on malaria[10] and antimalarial gene drive technology,[11] for instance, discuss the wide-ranging impacts of malaria in Africa and Asia in the same stroke as a few US cases. Such parallelism risks implying these problems are of equal severity. The potential that climate change renders malaria once again locally transmitted in the global North is important. But malaria in the global South deserves attention as a health crisis in its own right. As such, Smidler et al. only mention the deadliness of malaria in sub-Saharan Africa as the significance of their research.[6] “As we discuss these technologies, we really need to remind ourselves we are not the ones benefitting,” said Dr. Smidler.[7]

Building Research Capacity in Africa

Involving community partners helps ensure that malaria prevention interventions garner community support. Gaining informed consent is complex, however, when colonial impacts restrict the development of local scientific expertise. One effort to increase research capacity is the bilateral exchange program between UC San Diego (UCSD) and Universidade Eduardo Mondlane (UEM) in Mozambique,[12] one of the countries where malaria deaths are highest.[2] Given that there is no “silver bullet” for malaria,[7] African scientists with insight into their own communities can help develop technologies with diverse local contexts in mind.

Reframing Malaria Prevention

Smidler et al.’s research on mosquito biotechnology holds promise for malaria prevention, but we must reframe our discussions of such solutions. Focusing on malaria as an ongoing issue in Africa, poised to worsen with climate change, requires that we unpack malaria’s status as a looming “tropical” threat to the global North. Ultimately, Dr. Smidler’s research aims to protect African health, and implementation of such a technology requires cross-cultural collaboration. UCSD facilitation of research capacity at UEM will help foster new generations of biologists to determine their communities’ futures.

References

  1. Talapko J, Škrlec I, Alebić T, Jukić M, Včev A. 2019. Malaria: The past and the present. Microorganisms. 7(6).
  2. WHO. 2023 Dec 4. Malaria. World Health Organization. [accessed 2024 Feb 5]. https://www.who.int/news-room/fact-sheets/detail/malaria.
  3. Colón-González FJ, Sewe MO, Tompkins AM, Sjödin H, Casallas A, Rocklöv J, Caminade C, Lowe R. 2021. Projecting the risk of mosquito-borne diseases in a warmer and more populated world: A multi-model, multi-scenario intercomparison modelling study. The Lancet Planetary Health.
  4. Ranson H, Lissenden N. 2016. Insecticide resistance in african anopheles mosquitoes: A worsening situation that needs urgent action to maintain malaria control. Trends in Parasitology. 32(3):187-196.
  5. Bier E. 2022. Gene drives gaining speed. Nature Reviews Genetics. 23(1):5-22.
  6. Smidler AL, Pai JJ, Apte RA, Sánchez C HM, Corder RM, Jeffrey Gutiérrez E, Thakre N, Antoshechkin I, Marshall JM, Akbari OS. A confinable female-lethal population suppression system in the malaria vector, anopheles gambiae. Science Advances. 9(27):eade8903.
  7. Nuckowski KR, Smidler AL. 2024. Interview for Saltman Quarterly.
  8. Nájera JA, González-Silva M, Alonso PL. 2011. Some lessons for the future from the global malaria eradication programme (1955-1969). PLoS Med. 8(1):e1000412.
  9. Shahvisi A. 2019. Tropicality and abjection: What do we really mean by “neglected tropical diseases”? Developing World Bioethics. 19(4):224-234.
  10. Huang P. 2023 Dec 15. The U.S. is unprepared for the growing threat of mosquito- and tick-borne viruses. NPR. [accessed 2024 Feb 5]. https://www.npr.org/sections/health-shots/2023/12/15/1219478835/arboviruses-mosquito-tick-borne-viruses-tropical-disease.
  11. Allen G. 2024 Jan 26. New gene-editing tools may help wipe out mosquito-borne diseases. NPR. [accessed 2024 Feb 5]. https://www.npr.org/2024/01/26/1226110915/gene-editing-bioengineering-mosquito-disease-dengue-malaria-oxitec.
  12. UC San Diego School of Medicine. Mozambique. Division of Infectious Diseases & Global Public Health. [accessed 2024 Feb 5]. https://medschool.ucsd.edu/som/medicine/divisions/idgph/research/international/Pages/Mozambique.aspx