Dengue- a menace of climate change
Author: Dr. Sukheshni Nand (Bachelor in Dental Surgery)
Dengue is a mosquito-borne viral infection. Dengue fever is not transmitted from person to person. Only mosquito contracts the virus when it bites an infected person, therefore it is transmitted from the bite of an infected mosquito to person . The South Pacific has scattered island nations of Fiji, Samoa, Tonga, New Caledonia, Kiribati and Palau are currently struggling with an endemic of dengue.
South Pacific island countries face a growing threat from dengue fever as climate change spreads mosquitoes that carry the dengue-virus . According to WHO, rising temperatures and higher rainfall caused by climate change will result in an increasing number of mosquitoes in cooler areas where there is little resistance to the diseases they carry . Mosquitoes are very sensitive to changes in climate. Warmer conditions allow the mosquitoes and the malaria parasite itself to develop and grow more quickly, while wetter conditions let mosquitoes live longer and breed more prolifically .
Symptoms usually last for 2–7 days, after an incubation period of 4–10 days after the bite from an infected mosquito . The World Health Organization classifies dengue into 2 major categories: dengue (with/without warning signs) and severe dengue. Dengue causes flu-like symptoms that last for 2-7 days, including high fever (40°C), headaches, pain behind the eyes, nausea, vomiting, swollen glands, joint, bone or muscle pains, and/or rash . While severe dengue causes warning signs such as bleeding (gums, nose, blood in the stool, vomiting blood, vaginal bleeds, bruising or bleeding under the skin), persistent vomiting, abdominal pain, and restlessness or lethargy .
It is important to note that there is no vaccine or any specific medicine to treat dengue . Dengue fever can be fatal if the person remains untreated at home and comes to the hospital very late in the course of the disease. However, anyone with symptoms of dengue should seek medical care, and when warning signs of severe dengue are present (listed above), it is imperative to seek medical care to manage the disease. With early recognition and proper supportive medical care, case-fatality rates are below 1% .
In May 2020, Fiji reported 791 cases of dengue fever, mostly in the Northern and Central divisions . The country was still reeling from the devastation caused by cyclone Harold and heavy rains. Dengue spread from mosquitos that thrive from pools of still water that gathered after the storm . Fiji reported 1894 dengue cases in 2019 and 4000 cases of dengue and 9 deaths were officially recorded in 2018 . In 2012, there were 708 cases in Fiji, whilst in 2013 – 2014, Fiji experienced a dengue fever epidemic with over 15,000 cases confirmed . The Cook Islands reported 78 cases of dengue on 16 August 2019 . In early December 2018, Samoa's health ministry recorded 1,522 confirmed dengue cases with 339 hospital admissions and 4 deaths . In late January 2018, the Tongan government reported that there were at least 70 dengue cases, hence declaring an outbreak . On 27 February 2018, an ongoing dengue situation was reported in Vanuatu with 86 suspected cases. In New Caledonia, there have been 1,257 confirmed cases since 1 Jan 2018 including 112 hospitalizations .
Through the Pacific Syndromic Surveillance System (PSSS) – which is a part of the regional Pacific Public Health Surveillance Network – early recognition and identification of disease outbreaks, including dengue outbreaks were made possible . Ministries in affected countries and territories, such as Fiji, French Polynesia, and Kiribati took action with on-going surveillance of dengue to determine whether control interventions were working . Furthermore, the main method to control or prevent the transmission of the dengue virus is to reduce the number of vector mosquitoes by preventing them from breeding (vector control). On 16 January 2014, the Fiji Government launched a nationwide anti-dengue clean-up campaign to remove mosquito-breeding sites . In Kiribati, community-based efforts were focused on promoting environmental clean-up to remove mosquito breeding sites. Finally, Clinicians at all levels of the health system should be aware of a dengue outbreak, be able to identify cases that meet the dengue clinical case definition and be able to assess which patients have dengue warning signs and require hospitalization .
Raising public awareness on preventive measures, as well as educating everyone around us on the importance of consulting a doctor when someone falls sick, is imperative in controlling current and future dengue-fever outbreak . Additionally, the only effective responses to dengue outbreak are to work together, every individual, community, and institution, to reduce breeding sites such as discarded boats filled with standing water, tires, uncovered water storage and containers, and upturned coconut shells . To ensure that disease transmission is minimised, it is vital to protect ourselves and those suffering with dengue from getting bitten by the virus-carrying mosquitoes. This can be accomplished by using aids such as sleep under mosquito nets, use insect repellents, use windows with mesh/mosquito screens to keep mosquitoes out, dress to protect (long sleeves and pants), maintain a clean hygienic environment and destroy all breeding places of mosquitoes. Dengue outbreaks are long-lasting within populations; so increased surveillance, vector control, and clinical care will be needed for months to come .
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