Health Implications for September to November 2023

Respiratory Illness
  • The incidence of asthma and allergic rhinitis is likely to be lower compared to the previous season (June-July-August) due to less frequent episodes of Saharan dust incursions and lower levels of local dust into the Caribbean in the coming season.
  • Increased humidity – at even higher levels than usual for this time of the year – in the Caribbean islands and Belize throughout the period may cause dampness in some poorly ventilated residences and offices resulting in the growth of mould and increased cases of allergic reactions.
  • Where episodes of flooding may occur, particularly in the Caribbean islands and Belize, there is an increased risk of ear, nose, and throat infections from contact with contaminated water.

Gastrointestinal Illness
  • Following extreme weather events or disasters, there is an increased chance that the conventional means of water supply may be compromised resulting in persons seeking alternative water resources where the water is untreated and the water quality is unknown. This has the potential to increase the risk of gastrointestinal illness.
  • Where episodes of flooding may occur, cases of gastroenteritis may increase, where persons consume foods contaminated by these waters. This is the case across Belize and the Caribbean islands throughout the period, although the likelihood will be lower in the coastal Guianas at least until mid- to late-November.
  • In the unlikely event of lingering drought conditions, concentrations of water pollutants for small reservoirs and tanks may temporarily increase. This is mostly applicable to French Guiana, Guyana and Suriname which are in their dry season. Additionally, in some cases, a reduction in water pressure in distribution systems may result in cross-contamination and use of alternative, unsafe sources, in turn potentially causing higher incidences of gastrointestinal illness.

Non-communicable Diseases
    • Excessive heat from high temperatures across the region (exacerbated by humid air across the Caribbean islands) will first be of greater concern through the end of September before becoming less prevalent towards November. Moreover, especially during September and, possibly, in October anywhere further south than the Leeward Islands (or even in early-November in the Guianas), frequent heatwave days can increase the risk of morbidity from heat related illness in vulnerable persons, especially smaller children, the elderly, pregnant women and persons with NCDs.
    • Recent published research from the French Overseas Territories and unpublished research from Grenada found that levels of mortality, morbidity and the rate of hospitalisations from excessive heat are very likely to increase due to high temperatures and increasing humidity – especially during heat waves – across the region towards October.
    • In September and, anywhere south of Guadeloupe through October, there will be a significantly increased risk of heat stress which may present as a worsening in chronic conditions such as cardiovascular, respiratory, cerebrovascular disease and diabetes- related conditions. Symptoms can include lethargy, general weakness, dizziness, fainting and, in extreme cases, kidney failure. For information on heat and health see: and
    • During this period, excessive exposure due to dangerous UV radiation can cause skin damage in persons who spend extended periods outdoors, especially on sunny days (for more information, see: For simple action steps on sun protection see:
    • There is a possibility of skin infections due to contact with contaminated, stagnant and/or floodwaters, especially in the Caribbean Islands and Belize.

Vector-Borne Illness
  • As the Caribbean islands and Belize enter the peak of the Wet Season, increased rainfall, stagnant water in the aftermath of a flood, as well as water accumulating and/or stored in open containers may also potentially create more breeding sites for mosquitoes. These situations would increase the risk of associated mosquito-borne diseases such as Dengue, Chikungunya and Zika. However, note that in the case of flash floods, flood waters may sweep away mosquito eggs, larvae and pupae, potentially reducing mosquito populations for up to a few weeks after flash flooding.
  • In addition, higher temperatures increase the rate of development of mosquito vectors and mosquito populations, as well as increase the risk of transmission of vector borne diseases. Proper management of water storage containers (e.g., covering with protective mesh) helps to reduce this risk, particularly in the Guianas.
  • Episodes of flooding may occur in any flood-prone area of the Caribbean islands or Belize during this period. In such cases, there is an increased risk of Leptospirosis due to displaced rodents that could contaminate floodwaters, household items and food containers.
  • Access useful materials on mosquito control measures here: (; Join the fight against mosquito borne disease in the Caribbean: and

Well-Being and Mental Health
  • Severe weather systems, which can come with a range of hazards, including high winds, landslides, flash floods, among others, are expected to affect Caribbean territories. With the possibility of severe weather systems such as tropical cyclones, health practitioners and administrators should maintain a state of readiness.
  • In the face of tropical cyclones, there is an increased risk of injury or death from drowning in surging waters, high swells or rip currents.
  • In areas where flooding damages or destroys food crops, food insecurity may be a concern.
  • During heat waves, extreme weather events or disasters, vulnerable populations may have an increased need for medical care as they face a greater risk of poor health and even death. Health care providers and other stakeholders should clearly define and locate vulnerable populations, and develop tailored strategies for assisting them.
  • Peaks in heat stress associated with heat waves, can increase mood-affective and stress-related disorders, as well as, other mental and behavioural disorders. Persons taking medication for mental health disorders are at greater risk of heat-health effects.
  • Prolonged exposure to excessive heat in the upcoming period is highly likely to increase exhaustion during intense outdoor activity and limit labour productivity. It can further increase sweating and water consumption and, particularly during prolonged heat waves, lead to fatigue, irritability and aggression.
  • When disasters have seasonal patterns, including those caused by hurricanes, floods and drought, psychosocial impacts such as anxiety among survivors may increase as alerts on isolated events arise. Health care professionals are therefore advised to be sensitive to these issues, as they interact with patients.

COVID-19 and Climate Impacts
  • Water quantity and quality is critical to support prevention strategies to combat the COVID-19 pandemic, especially with regards to safe water for hygiene purposes. Flooding and drought may affect continuous access to safe water. Therefore, special attention should be paid to impacted communities.
  • Any disaster occurring will compound psychosocial impacts related to the COVID-19 pandemic, particularly disasters arising from extreme weather events. Health care professionals are therefore advised to be sensitive to these issues, as they interact with patients.
  • Extreme weather events or disasters may cause an increased burden on already stressed healthcare services and the rollout of vaccination campaigns. Countries should factor this into their contingency plans and actions.

This Bulletin provides a broad overview of climate conditions up to 3 months in advance. It is based on insights drawn from CIMH’s suite of technical climate information products and epidemiological insights from CARPHA and PAHO. The information contained herein is provided with the understanding that the CARPHA, the PAHO and the CIMH make no warranties, either expressed or implied, concerning the accuracy, completeness, reliability or suitability of said information. The Bulletin may be freely used and disseminated by the public with appropriate acknowledgement of its source but shall not be modified in content and then presented as original material.