Precious Kondwani
Mchepa

On 11 March 2023, Tropical Cyclone Freddy made its second landfall over southern Malawi, ultimately making it the longest-lasting tropical cyclone ever recorded globally (WMO, 2023). It killed over 1,200 people and also displaced more than half a million people. Within days, floodwaters had contaminated wells and streams across Blantyre, Mulanje, and Phalombe, and cholera cases surged past 1,000 in under two weeks. Freddy was more than a weather disaster. It was a public health catastrophe wearing a meteorological mask.

That link between climate and disease is natural, no coincidence. Malawi is at a convergence of geographic vulnerability, ecological fragility, and a health system stretched beyond its limits, with just 0.4 physicians per 1,000 people and a health budget that has rarely exceeded five percent of GDP (WHO, 2022). Climate shocks are arriving faster than the country can absorb them. Rising temperatures are enhancing the distribution of mosquitoes, floods are turning sanitation infrastructure into breeding sites, deforestation is dissolving the protected vegetative zones, that historically kept animal pathogens away from human communities.

Understanding this crisis requires the One Health framework, which recognizes that human, animal, and environmental health are not separate domains but one interconnected system. Climate change is not threatening Malawi through a single mechanism; it is working through a web of ecological, biological, and social disruptions simultaneously. This essay examines those disruptions across three disease categories: vector-borne, waterborne, and zoonotic, and argues that only a coordinated, evidence-anchored response can slow the damage of climate change.

Vector-Borne Disease: Malaria Beyond Its Old Boundaries

Malaria accounts for roughly 40 percent of all outpatient visits in Malawi and remains a leading cause of death in children under five (Ministry of Health, Malawi, 2022). For decades, control efforts concentrated resources where the burden was historically highest in lowland and lakeshore areas where Anopheles mosquitoes reliably thrived. That geography no longer holds.

Warmer temperatures accelerate the sporogonic cycle of Plasmodium falciparum, the parasite responsible for the most dangerous form of malaria. It matures faster inside the mosquito, raising the proportion of any mosquito population that is infectious at a given time. To more consequences, the minimum temperatures during nighttime that once prevented Anopheles survival above roughly 1,500 metres are rising. In highland districts, Dedza, Ntcheu, and Zomba, communities that historically had minimal malaria exposure are now recording transmission. This matters enormously because they carry little acquired immunity. When malaria arrives among unexposed populations, there are worse cases and more deaths. A study modelling this dynamic across East and southern Africa found the altitudinal expansion was already measurable, not merely projected (Siraj et al., 2019). Malawi fits squarely in the affected zone.

Flooding adds a different layer. After Cyclone Ana struck in January 2022, Nsanje District recorded a sharp rise in malaria admissions that pushed district hospital capacity past its limit (MOHP Malawi, 2022). Stagnant post-cyclone water becomes a vast mosquito breeding ground, enhancing short-term and intense exposure. The disease itself did not change, the climate made conditions for it far worse, far faster.

Waterborne Disease: When Sanitation Cannot Survive the Weather

The 2022-2023 cholera outbreak was the worst in Malawi's recorded history. By June 2023, more than 58,000 cases and 1,774 deaths had been confirmed, a case fatality rate of approximately three percent, three times the WHO emergency threshold, signaling that patients were reaching care too late or not at all (WHO, 2023). Climate events were the accelerant.

Even in stable conditions, Malawi's water and sanitation infrastructure is fragile. Only 17 percent of the rural population accesses safely managed drinking water, and open defecation remains common in flood-prone districts like Chikwawa and Nsanje (UNICEF/WHO, 2021). Cyclone Ana broke through pit latrines, contaminated boreholes, and destroyed piped water schemes across the south in January 2022. Cholera followed within weeks. Cyclone Freddy, arriving fourteen months later into an already weakened system, produced the catastrophic second surge. Vibrio cholerae did not emerge from nowhere, it exploited a human caused climate collapse in the barriers separating pathogen from host.

The pattern extends beyond cholera. Schistosomiasis is endemic in communities along the Shire River system, and warmer water temperatures accelerate freshwater snail reproduction, the intermediate host in the parasite's life-cycle. Typhoid and hepatitis A follow the same flooding logic as cholera. Each relies on the same vulnerability: a population that cannot afford the safety margin between contaminated water and drinking water, and a climate that is now systematically destroying whatever buffer exists.

Zoonotic Disease: Shrinking Forests, Narrowing Distance

Of the three disease categories, zoonotic spillover carries the greatest long-term uncertainty. Approximately 60 percent of known human infectious diseases originate in animals, and the ecological conditions driving spillover, habitat destruction, stressed wildlife populations, and increasing human-animal contact are precisely what climate change and land-use pressure are producing in Malawi (UNEP, 2020).

Deforestation is the most direct mechanism. Malawi lost over 33 percent of its forest cover between 1990 and 2020, driven by charcoal production, smallholder agriculture expansion, and tobacco farming (FAO, 2020). As forests contract, the wildlife within them, bats, rodents, and non-human primates, all known reservoirs for pathogens with no established human host, are pushed into closer proximity to farming communities. This is how most novel zoonotic viruses historically emerge: not through dramatic single events, but through the slow erosion of distance between reservoir species and human populations.

Anthrax illustrates the climate dimension concretely. Bacillus anthracis spores can remain viable in soil for decades. Cycles of flooding and drought disturb burial sites where infected carcasses lie, surfacing spores into grazing land. Malawi has documented anthrax in hippopotamus and cattle populations in the Lower Shire Valley, with associated human exposure risk among communities that handle or consume wild game (FAO, 2018). Climate variability does not create anthrax; it destabilises the soil conditions that contain it. The same logic applies whether the pathogen is anthrax, a novel coronavirus, or a haemorrhagic fever: ecological stability is a public health asset Malawi is steadily losing.

The Malnutrition Multiplier and the Need for One Health Solutions

There is a dimension this analysis cannot afford to leave out. Malawi's child stunting rate stands at 37 percent, and chronic food insecurity affects the majority of rural households in drought years (World Bank, 2023). Malnutrition does not simply generate its own disease burden; it amplifies every other infectious disease burden by compromising immune function. A malnourished child with malaria is far more likely to deteriorate into severe disease. A malnourished adult with cholera dehydrates faster and responds less reliably to oral re-hydration. Climate change is, through drought and flood, systematically expanding the population of people whose immune defences cannot mount an adequate response to infection. Treating malnutrition as a separate problem from the infectious disease burden is working with an incomplete picture of what is actually happening.

Addressing this requires the One Health approach to move from principle to practice. Malawi's Integrated Disease Surveillance and Response system needs direct linkage to meteorological forecasting, so that a cyclone warning automatically triggers pre-positioned cholera response supplies in high-risk districts. Climate-resilient water infrastructure in the Shire Valley flood corridor must be treated as an emergency public health investment, not a development aspiration. And the Ministry of Health, the Department of Forestry, and wildlife authorities need shared data systems, because the next spillover event will not wait for institutional coordination to catch up.

Conclusion

Cyclone Freddy did not create cholera in Malawi. It unlocked it. Rising temperatures do not create malaria in the highlands; they unlock conditions for it. Deforestation does not generate zoonotic viruses: it removes the distance that kept them contained. This is the perspective of climate change and infectious disease in Malawi: not creation, but the systematic removal of the barriers between pathogen and person.

Malawi contributes less than 0.01 percent of global greenhouse gas emissions. The disproportion between its climate responsibility and its climate exposure is a fact worth naming plainly. But naming it does not change what the country must do: build surveillance systems that anticipate outbreaks, invest in infrastructure that survives the weather now arriving with regularity, and treat the boundaries between human, animal, and environmental health as the fiction they have always been. One Health is not an academic framework here. It is a description of a crisis in motion, and the most honest starting point for slowing it.

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