Is climate change increasing dengue risk? – Prism

As temperatures rise and the monsoon unleashes its fury, dengue may move to areas not affected by it.

A boy is examined in the dengue room of Benazir Bhutto Hospital, Rawalpinidi – Photo: Sara Farid

Last week, thousands of young Pakistanis, energized through calls from Climate Action Pakistan to a climate attack, marched through the main cities of the country to call attention to a critical challenge.

Climate change is affecting countries around the world; However, developing nations are the most affected by extreme weather events due to a combination of complex interrelated factors. One of the impacts of climate change that has been most pronounced recently is the increase in vector-borne diseases.

According to the World Health Organization (WHO) vectors, pathogens and hosts survive and reproduce in optimal climatic conditions, including temperature and rainfall. WHO continues to affirm that “rain can influence the transport and spread of infectious agents [including anthroponosis like dengue fever], while temperature affects its growth and survival. "

The spread of dengue has expanded, and WHO reports that 50 to 100 million infections occur annually in more than 100 countries. About 45 percent of the world's population, or 3.6 billion people, live in countries with a high risk of dengue. Pakistan is one of them and once again has been affected by dengue this year, with more than 10,000 cases reported so far across the country.

How dengue is spread

Dengue itself is a flavivirus that is transmitted through the Aedes aegypti mosquito. Symptoms include high fever, headache, muscle and joint pain and vomiting accompanied by a characteristic skin rash. In severe cases, it can cause bleeding, organ failure and, ultimately, death.

the Aedes aegypti It is a small dark-colored mosquito with visible white markings (dots or stripes) on its body and legs. The maturity cycle of this mosquito, from the egg to the adult, is only one week, which makes it an extremely effective vector that can turn dengue into an epidemic.

Unlike other types of mosquitoes, Aedes mosquitoes are more active during the day; The peak bite periods are the first mornings and the hours before sunset. When preferring to stay in homes and indoors, this mosquito usually goes unnoticed because it approaches people from behind, usually biting the ankles and elbows.

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the Aedes the mosquito thrives in the shade and in areas with poor sanitation. The Centers for Disease Control and Prevention of the United States adds that standing water is essential for Aedes Mosquito to lay their eggs. Eggs can survive up to six months, but they need water to hatch. The monsoon season, therefore, creates an ideal environment for the colonies of this mosquito to thrive and reproduce.

Daily rains cause puddles and wet spots in parks, cemeteries, scrap yards and roofs, creating a perfect atmosphere for the Aedes mosquitoes to live and reproduce. Stagnant water as a result of urban or river floods can also promote population and vector propagation.

Therefore, the ideal larval habitats for this mosquito are puddles, open water storage containers, particularly dark colored containers, desert coolers, water dispensing trays, abandoned water tanks, coal tar drums, tree hollows , flower and plant pots, broken or unused pots of land. , discarded tires, garbage and garbage that accumulates water (such as plastic bags and construction debris), buckets, fountains, underground water and sewer tanks, wells, drains, etc.

As the weather cools, the Aedes the mosquito disappears; It cannot survive temperatures below 14 degrees Celsius.

Previous outbreak and lessons

In 2011, more than 21,000 people were infected with dengue in Punjab, and 354 succumbed to the disease. An investigation conducted by the Punjab Provincial Disaster Management Authority, presented in the book Dengue prevention and control: Lahore's success model, concluded that precipitation is a more influential factor than the temperature in the propagation and reproduction of Aedes family mosquitoes

The investigation continues by adding that rain was the biggest contributor to the dengue outbreak; Heavy rains in Lahore had caused urban flooding that resulted in large puddles of standing water, particularly in parks and cemeteries. This created an ideal environment for vector-borne diseases to be established in the city and in a matter of weeks. Aedes mosquitoes not only reproduced, but thrived in exponential numbers.

Adequate government interventions in a timely manner ensured that the epidemic was contained, and did not explode with a remotely comparable intensity in the following years. The predictive model had estimated more than 55,000 infections and almost 1,000 deaths, but conscientious efforts at various administrative levels overturned the virus when it was installed.

The same book details how the Punjab government set out to address this gigantic challenge; the incredible amount of coordination required; and the magnanimous efforts of each part of the government machinery to contain dengue.

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Some of the best practices that helped contain dengue in 2011 include the clever use of data to create GIS-based maps of areas with high infection rates. This allowed decision makers to identify problem points such as parks and cemeteries at the beginning of the process. For example, in Lahore, Model Town and the towns surrounding the Miani Sahib cemetery had a disproportionately high number of dengue cases.

Meanwhile, the health department reported the addresses of the patients to the Municipal Administrations of the city in question, which fumigated the patient's home and surrounding houses, thus eliminating a confirmed source of dengue and larval infection. A three-tier system based on an initial surveillance team, a second fumigation team and a follow-up evaluation team was implemented to ensure larval eradication.

The city district government launched a comprehensive vector control program, in collaboration with the health department. Vector control was largely achieved through chemical means, which included nebulization, internal residual spraying and larvicide. While the workers started howling fog machines, others filled ponds and drained stagnant water from parks and empty plots.

All major parks were chemically treated to control the spread of Aedes Mosquitoes and larvae, and green belts and nurseries were inspected to ensure the elimination of possible mosquito breeding sites. More than 100,000 tilapia, carps and mosquitoes were introduced in more than 100 large ponds to eradicate Aedes larvae In the sanctuaries, water deposits and open areas of ablution were sprayed.

Efforts were also intensified to ensure the daily disposal of garbage and waste, which could otherwise accumulate water. Additional health workers were deployed in selected areas and the dumping of garbage in vacant plots was minimized. Nearly 4,000 tons of solid waste were disposed of daily from the city, in addition to regular trash.

Engaged Auqaf officials ulema Y magnets to raise public awareness through Friday sermons and other religious meetings. The government also involved stakeholders in private housing societies for dengue awareness events and ensured that spraying was carried out regularly. Fumigation was also carried out in all government schools, colleges and universities. Many of these educational institutes were closed for a period of 10 days at the peak of the dengue outbreak to accommodate fumigation and decontamination.

The participation of university and university students in various social action campaigns served as a crucial part of the mass awareness campaign, which was also promoted through print, electronic and digital media. Two training workshops were organized at each secondary school and university to efficiently mobilize young people.

These workshops were followed by student-led activities, such as surveys of their schools and locations for the identification of hatcheries and door-to-door awareness campaigns under teacher supervision. These activities, in combination with the abundant use of information, education and communication materials such as banners, brochures, posters and panaflexes, increased basic awareness about dengue.

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The Information Technology Board of Punjab (PITB) established a dedicated helpline attended by 150 doctors 24 hours a day to attend queries related to dengue. The PITB also established the Electronic Complaint Routing System, which was a successful example of community participation in dengue eradication efforts.

Citizens were able to report relevant complaints through a single telephone number; These complaints were then classified and sent to the corresponding department for immediate repair. This effort allowed the identification of empty and empty plots that require fumigation, abandoned properties, scrap yards and other possible habitats for Aedes breeding.

NGOs and social assistance organizations were mobilized to complement dengue eradication efforts and improve community-level awareness. The volunteers were trained to conduct dengue awareness seminars in Lahore. Hospitals operated by NGOs and trusts played a key role in the treatment of dengue patients, and many private hospitals also provided free dengue treatment.

Finally, all the aforementioned efforts were complemented by a high-ranking committee of public representatives, secretaries of all interested departments and health experts for effective coordination of efforts and daily operational decision making that would otherwise have been hampered by bureaucracy.

Additional adaptation

Historically, dengue has been seasonal. Normally, cases would begin to fall in November with the conclusion of the rainy season and resume in June. However, in Central America, the virus resurfaced with vengeance in January, indicating a possible change in the nature of the disease. Aedes mosquito, or contribution of other vectors in the spread of dengue.

Predictive modeling can be used to understand changing weather patterns in Pakistan. As temperatures continue to rise, and heavy monsoon rains unleash their fury, the risk of dengue is likely to shift to those areas that have not yet been affected by it.

Rapid urbanization and high internal migration in Pakistan are paving the way for fungal growth in illegal settlements. These locations are dispersed in urban areas, from the city center to the peripheral, suburban or peri-urban areas, and generally lack adequate sanitation and solid waste management infrastructure.

After periods of heavy rains, slums are usually the most affected, with water accumulated at rest for several days. The lack of access to health facilities for residents of the slums creates an ideal environment for an epidemic outbreak.

Based on information from other countries facing the epidemic, for example, Bangladesh and Honduras, which reported the maximum number of infections in children aged five to nine, a school-wide strategy must be revitalized to raise awareness among children and Parents about the risks and signs of dengue. Children have fewer defenses and greater exposure because they attend school and play outside. Vulnerabilities among street children must also be taken into account in the equation.

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A level of complacency among the population may contribute to the fact that limited cases of dengue were reported in recent years. But that is the way this virus acts, a few years of calm followed by an epidemic outbreak. When an outbreak occurs, health experts report that patients do not seek immediate treatment, which further aggravates the situation.

This underscores the need for multiple behavior change communication campaigns across schools, colleges, universities and the media to promote positive behaviors in the local population.

While a definite relationship between dengue larvae with temperature or humidity has not been established, frequent rains during the monsoon season promote Aedes breeding and, therefore, preventive and chemical control measures should be organized during this period.

An annual fumigation campaign before the start of the monsoon season should be an essential element in the government checklist. Repeated incidents of urban flooding require coordinated measures to drain standing water and puddles, and fill ponds and bodies of water where drainage may not be feasible.

Finally, the government should consider setting up an emergency response committee or a joint working group, chaired by the province's executive director, with decision makers from key departments, sector specialists and representatives from allied sectors to formalize sustainable measures to Long term to fight dengue.

The government needs to be better prepared for epidemics, floods and other events in this era of climate change; No one should suffer as a result of lack of foresight.

This article was prepared by a thorough review of the information of a combination of resources. It is for information only; The opinions expressed in this document are not intended for any medical or clinical use, or for implementation in the field without the advice or consent of such individuals as required by local laws and regulations.

Are you seeing the impacts of climate change on health? Write to us at [email protected]



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