The Impact of Climate Change on Vector-Borne Diseases in Haiti
Climate change poses a significant threat
to developing countries impacting ecosystems, socio-economic development, and
public health. Haiti is not an exception. Its diverse manifestations, including
droughts, floods, and extreme weather events, disrupt biodiversity and
contribute to the emergence and spread of human and animal diseases. While
Haiti contributes minimally to global greenhouse gas emissions, it heavily
feels the consequences. Ecosystems around the intertropical convergence zone
are particularly vulnerable, potentially linked to the occurrence of
vector-borne diseases. Although evidence suggests climate change amplifies
vector-borne diseases, research specifically exploring this link in Haiti
remains limited.
This study
explores the link between climate change and the spread of diseases carried by
insects and other animals (vector-borne diseases) in Haiti it addresses the
double threat of climate change and vector-borne diseases in Haiti, exploring
both global and local perspectives. It examines the impact on health, the
current landscape of these diseases. It suggests areas for future research and
proposes solutions for decision-makers. Understanding these connections is
crucial for Haiti to safeguard public health and lessen the harm caused by
climate change.
Climate
change and environmental degradation
The Intergovernmental Panel
on Climate Change (IPCC) paints a sobering picture of our future, predicting
global temperature increases ranging from 1.4 to 5.8°C by 2100. This warming
will impact both human and ecological systems, from rain to humidity.
Developing countries as Haiti face substantial challenges due to these changes.
Rising temperatures
and increasingly frequent droughts create a perfect storm for new environmental
threats. Studies in Haitian cities have already detected harmful pathogens like
Cryptosporidium oocyst in both surface water and groundwater used for drinking,
highlighting the potential health risks. Climate change not only affects water
resources but also influences the behavior and survival of infectious agents.
Increased rainfall can facilitate the spread of pathogens, while higher
temperatures allow them to thrive and persist for longer periods. Its geography
and demography enhance the risks. Situated at the meeting point of
tectonic plates, Haiti experiences frequent earthquakes and sits in the direct
path of storms while rapid population growth and deforestation exacerbate the
impact of these events.
Haiti ranked third among nations most affected by climate risks between
1993 and 2012. These environments threats also affect its socio-economic
aspect.
Climate
change & environmental alterations: effects on health & vector-borne
diseases
Climate change, driven by
greenhouse gas emissions from industrialized nations, is causing major climatic
disturbances. These changes, including rainfall shifts and extreme weather
events, are linked to the emergence and re-emergence of infectious diseases,
particularly those transmitted by vectors like mosquitoes and ticks. Human
activities are linked also, deforestation and travel can exacerbate ecological
imbalances, introducing new pathogens and promoting disease transmission.
While establishing the
precise role of climate in these diseases is complex, organizations like the
IPCC warn of changes in vector-borne disease transmission. Examples include the
rapid spread of Chikungunya in 2007 and 2014, likely facilitated by changing
mosquito distribution and human mobility. Similar scenarios might be unfolding
with other mosquito-borne diseases like dengue and Zika.
Considering the vulnerable
agriculture, deforestation and pests threaten food security and health, CO2
absorption raises acidity, harming marine life and impacting food chains. The
"One Health" approach recognizes the interconnection between human,
animal, and environmental health.
Vector-Borne Diseases in
Haiti: Epidemiological Landscape
Mosquitoes are the most
prevalent vectors in Haiti, transmitting diseases like dengue, chikungunya, and
Zika. However, other vectors like ticks, flies, sandflies, and fleas also pose
threats. Fighting these vector-borne requires a deep understanding of their
epidemiology. This involves gathering crucial information about the pathogens,
vectors, and disease characteristics. It includes: 1)
Knowing if they are cultivable, their source (animals, environment, humans),
and susceptibility to treatments (pathogen)
2) Understanding their distribution, competence (ability to transmit the
disease), and capacity (influenced by environmental factors, vector density,
and infectiousness). 3)Determining incubation
period, transmission duration, and impact of physical and infectious agents
(diseases).
A major public health
problem, malaria is primarily transmitted by Anopheles mosquitoes. While Haiti
aimed to eliminate the disease by 2020, it fell short.
However, while not yet
considered a major disease, dengue fever is transmitted by Aedes mosquitoes and
has been detected in Haiti. Studies have shown high seroprevalence of dengue
antibodies in the population, suggesting hyperendemic transmission.
First detected in Haiti in
2014, chikungunya caused widespread illness with severe arthralgia. Serological
tests indicate rapid and intense spread of the virus.
Zika virus infection, linked
to congenital microcephaly and neurological complications, emerged in Haiti in
2015. Although often asymptomatic, thousands of suspected cases were reported.
Strengthening surveillance and laboratory capacity is essential.
Conclusion: Vector-borne
diseases pose a significant public health burden in Haiti.
Climate Change and The
Global Health Approach
What is One Health? Why is it
important?
One Health emphasizes that solving
complex health problems requires collaboration across disciplines. It acknowledges
how changes in the environment, where humans and animals co-exist, influence
disease outbreaks. The American Veterinary Medical Association defines it as
"a joint effort to optimize human, animal, and environmental health."
This approach goes beyond zoonoses (diseases transmitted from animals to
humans), encompassing food safety, security, antimicrobial resistance, and
climate change responses. This approach offers promising solutions for climate
change adaptation. For example, promoting sustainable livestock practices,
improving animal feed quality, and establishing integrated surveillance systems
can enhance food security and combat vector-borne diseases, particularly in
developing countries.
Direct and indirect impacts of
climate change on human health
Direct impacts
a)extreme
temperatures which can cause heatstroke, respiratory problems, and increased
mortality, particularly among vulnerable populations. b) the distribution and abundance of disease-carrying vectors like
mosquitoes and ticks, leading to the spread of vector-borne diseases. c) Increased air pollution, including ozone and
particulate matter, can trigger respiratory illnesses like asthma and COPD. d) Floods and
droughts can contaminate water sources, leading to outbreaks of waterborne
diseases like cholera and diarrhea.
Indirect impacts
These are: food security, mental
health, and economic impacts.
Impacts on Animal health: Climate change affects animal health directly through heat
stress and indirectly through changes in feed availability, pathogen
distribution, and vector abundance.
Vector control methods
These are respectively biological, physical, chemical,
and sanitary: a) the use of larvivorous
fish in water bodies. b) use of Use barriers like
mosquito nets and modification of the environment to reduce vector populations c) use of larvicides, indoor spraying,
insecticide-treated nets, and space spraying (judiciously). d)
improving overall environmental health by removing sources of unhealthy
conditions.
Conclusion
As climatologist Katharine
Hayhoe emphasizes, "climate change is real, humans are responsible, and
its consequences are serious." Heat waves, ocean acidification, and other
climate-related changes affect the life cycles of these vectors, favoring their
spread and enabling the emergence of new diseases. This expansion extends the
reach of existing vector-borne diseases into previously unaffected regions,
particularly temperate zones. Strengthening
surveillance, improving laboratory capacity, and conducting further research
are crucial steps to protect Haiti's population from these potentially
devastating illnesses. Addressing climate change and its impact on vector-borne
diseases requires a global, multidisciplinary approach to protect human health
and our planet's well-being.
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