J. Microbiol. Infect. Dis., (2024), Vol. 14(3): 093–094

Letter to the Editor

10.5455/JMID.2024.v14.i3.1

Floods in southern Brazil and the risk of increased disease occurrence

Phelipe Magalhães Duarte¹, Sina Salajegheh Tazerji² and Kannan Subbaram^3*

¹Postgraduate Program in Animal Bioscience, Federal Rural University of Pernambuco (UFRPE), Recife, Brazil

²Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran

³School of Medicine, The Maldives National University, Male’, Maldives

*Corresponding Author: Kannan Subbaram. School of Medicine, The Maldives National University, Male’, Maldives. Email: kannan.subbaram [at] mnu.edu.mv

Submitted: 09/06/2024 Accepted: 25/08/2024 Published: 30/09/2024

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I am writing this letter to the editor, to report on floods in Southern Brazil and the risk of increased disease occurrence, as the state of Rio Grande do Sul faces its worst natural catastrophe, and it is worth noting that this is the third major flood in less than 1 year, which could result in devastating consequences, not only for human, animal, and environmental health, but also economic, social, and psychological.

Extreme weather and climate events, such as heatwaves, droughts, and heavy precipitation, have become increasingly common in recent decades (AghaKouchak et al. 2020; Fischer et al. 2021). Until then, Brazil was a country that did not suffer major consequences from natural disasters. However, in recent years, several disasters have been reported, such as extreme fires in the North, especially in the Amazonia (UOL 2024), and in the Central-West, especially the Pantanal (G1 2023). It is worth highlighting that these disasters are not consequences of climate change alone, but also of human actions, which have been increasing the effects caused by climate change on our planet.

The state of Rio Grande do Sul, located south of Brazil, is facing an extreme weather event, with immense rainfall volumes in short periods, leading to catastrophic flooding. In some cities in Rio Grande do Sul, the precipitation between April 22nd and May 6th equaled the entire average precipitation expected for 5 months, with some cities surpassing 700 mm (Lamas 2024). This rainfall led the state capital, Porto Alegre, to experience its worst flood in history (Coelho 2024). The state, which has agribusiness as its main economic activity, was hit hard by floods that devastated numerous cities. This climatic catastrophe has already impacted 444 out of the state’s 497 municipalities, affecting 1,951,402 people, 339,928 displaced, 71,398 in shelters, 756 injured, 141 missing, and 136 deaths. In total, 74,153 people and 10,348 animals have been rescued (Defesa Civil do Rio Grande do Sul 2024).

Hurricane Katrina’s passage through the United States, for example, left 1,400 dead and more than 1 million homeless (Corrêa 2024). With this significant flooding, risks to human and animal health are imminent, especially from diseases such as leptospirosis, hepatitis A, toxoplasmosis, giardia, and tetanus. Displaced individuals, volunteers, rescuers, and all those in contact with water are at risk. Additionally, respiratory and gastrointestinal diseases may also afflict the population, as water supply has been compromised in some regions due to the flooding of the pump system that should supply water to treatment and sanitation plants. The state should also be prepared for diseases caused by fungi and parasites, as the sanitation and water supply system has been damaged. Furthermore, the effects of floods can put the public health system into overload leading to a collapse.

It is worth noting that Brazil is facing one of its worst dengue epidemics in decades, with approximately 4.2 million cases, 2,149 deaths, and another 2,271 deaths under investigation (Felix 2024). The flooding scenario provides an ideal environment for the proliferation of the disease vector. Therefore, even after the river waters recede, intensive and uninterrupted control action will be necessary in the state. Animals are also susceptible to various risks besides diseases such as leptospirosis. Many people ended up separated from their animals, leading to a large number of abandoned or lost animals.

Furthermore, floods impact people’s lives and health in other ways, such as exposure to adverse conditions, which can result in hypothermia, dehydration, malnutrition, and disorientation.

The effects of the catastrophe on the water, electrical, internet, and telephone supply systems impacted thousands of people, with approximately 236,888 points without electricity and at least 129,977 people without water supply (Takahashi 2024). Furthermore, it is worth noting that in Brazil, winter begins, with temperatures in the south of the country close to zero, which further increases the impacts of this catastrophe.

Another impactful factor, certainly, is the sudden environmental change resulting from the floods. An incalculable number of domestic animals died. Numerous wild animals have had their habitat impacted, which could pose a risk to public health, as they may seek shelter in cities, bringing with them their parasites and microorganisms. It will be essential to implement intensive control actions for a long period in the state of Rio Grande do Sul, not only for rapidly emerging diseases but also for medium and long-term problems.

In light of this disaster, it is essential that basic services such as water supply and electricity are reestablished as quickly as possible.

Rescues must continue intensively, especially in regions that are difficult to access.

The supply and distribution of water and food by public authorities becomes vital in this scenario, since thousands of families have lost all their assets.

It is necessary that preventive health actions are already implemented, especially with regard to leptospirosis, hepatitis, and tetanus.

It is not possible to ignore problems related to parasitic diseases, such as giardia, as well as respiratory diseases, both as a result of winter and fungal proliferation in homes due to high humidity. Therefore, cleaning and decontamination teams must be aware of this, using products such as sodium hypochlorite.

Public authorities must be prepared for the increase in cases of vector-borne diseases, such as dengue. Therefore, it is essential that actions to prevent and mitigate mosquito proliferation are intensified.

The reconstruction of cities must be planned in order to prevent future floods, whether through relocation, construction of protective walls or dikes, drainage pumps and, mainly, emergency plans, which will be distributed to the entire population.

The public health system must be significantly strengthened, both in terms of human resources, materials, and inputs.

Public authorities also have to be prepared for the high number of lost or abandoned animals. Studies on the impact on the environment will be extremely valuable.

In parallel with this, monitoring of wild animals displaced from their natural habitats must be carried out.

The consequences of climate change seem to have definitively reached Brazil. The time for change no longer seems infinite, demanding drastic and immediate changes to our environmental actions and policies. Postponing or mitigating these actions has proven that the price to be paid is too expensive, and could cost us our survival on our planet.

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.

Author Contributions

All authors have read and agreed to the published version of the manuscript.

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References

AghaKouchak, A., Chiang, F., Huning, L.S., Love, C.A., Mallakpour, I., Mazdiyasni, O., Moftakhari, H., Papalexiou, S.M., Ragno, E. and Sadegh, M. 2020. Climate extremes and compound hazards in a warming world. Ann. Rev. Earth. Planet. Sci. 48, 519–548. https://doi.org/10.1146/annurev-earth-071719-055228

Coelho, T. 2024. Com mais chuva, universidade do RS prevê novo recorde de cheia no Guaíba. CNN Brasil. Available via https://www.cnnbrasil.com.br/nacional/com-mais-chuva-universidade-do-rs-preve-novo-recorde-de-cheia-no-guaiba/ (Accessed 20 May 2024).

Corrêa, A. 2024. O que o Rio Grande do Sul pode aprender com as falhas na resposta ao Katrina nos EUA. G1 Meio Ambiente. Available via https://g1.globo.com/meio-ambiente/noticia/2024/05/15/o-que-o-rio-grande-do-sul-pode-aprender-com-as-falhas-na-resposta-ao-katrina-nos-eua.ghtml (Accessed 20 May 2024).

Defesa Civil do Rio Grande do Sul. 2024. Defesa Civil atualiza balanço das enchentes no RS—5/11, 9h. Defesa Civil do Rio Grande do Sul. Available via https://www.defesacivil.rs.gov.br/defesa-civil-atualiza-balanco-das-enchentes-no-rs-5-11-9h (Accessed 20 May 2024).

Felix, P. 2024. Brasil supera os 4,2 milhões de casos de dengue previstos para 2024. Veja. Available via https://veja.abril.com.br/saude/brasil-supera-os-42-milhoes-de-casos-de-dengue-previstos-para-2024 (Accessed 20 May 2024).

Fischer, E.M., Sippel, S. and Knutti, R. 2021. Increasing probability of record-shattering climate extremes. Nat. Clim. Change 11, 689–695. https://doi.org/10.1038/s41558-021-01092-9

G1. 2023. Pantanal: fogo já devastou área quase oito vezes maior que o Rio em 2023. G1 Mato Grosso do Sul. Available via https://g1.globo.com/ms/mato-grosso-do-sul/noticia/2023/11/14/pantanal-fogo-ja-devastou-area-quase-oito-vezes-maior-que-o-rio-em-2023.ghtml (Accessed 20 May 2024).

Lamas, J.P. 2024. Chuva em pontos do RS bate a média prevista para cinco meses: veja lista de cidades com maior acumulado. G1 Meio Ambiente. Available via https://g1.globo.com/meio-ambiente/noticia/2024/05/07/chuva-em-pontos-do-rs-bate-a-media-prevista-para-cinco-meses-veja-lista-de-cidades-com-maior-acumulado.ghtm l (Accessed 20 May 2024).

Takahashi, L. 2024. Casas alagadas, sem luz e falta de água: chuva afeta 20% de moradores do RS. UOL Notícias. Available via https://noticias.uol.com.br/cotidiano/ultimas-noticias/2024/05/16/chuva-afeta-20-das-pessoas-no-rs.htm (Accessed 20 May 2024).

UOL. 2024. Amazônia bate recorde de queimadas em fevereiro. UOL Notícias. Available via https://noticias.uol.com.br/ultimas-noticias/agencia-estado/2024/02/27/amazonia-bate-recorde-de-queimadas-em-fevereiro.htm (Accessed 20 May 2024).