DENGUE - THE BREAKBONE FEVER
DENGUE - THE BREAKBONE FEVER
By
Dr. Wahied Khawar Balwan & Sachdeep Kour
Dengue is one of the most critical and rapidly spreading vectorborne disease in the world. It is caused by an RNA virus that belongs to the Flaviviridae family. The dengue virus is transmitted by mosquitoes (arthropods) and thus is an arbovirus. Dengue spreads through the bite of female Aedes mosquitoes. Aedes mosquitoes also serve as vectors of chikungunya, yellow fever and Zika viruses. The symptoms may range from asymptomatic fever to dreaded complications such as hemorrhagic fever and shock. Dengue is an endemic disease, which means that it occurs regularly, in tropical regions of the world. According to World Health Organization (WHO), almost half of the world’s population lives in areas with a risk of contracting dengue virus. The risk of contracting dengue infection has increased dramatically since the 1940s. This upward trend is due to increases in long-distance travel, population growth and urbanization, lack of sanitation, ineffective mosquito control, and increases in the surveillance and official reporting of dengue cases.
INTRODUCTION
Dengue is an acute viral infection with potential fatal complications. Dengue fever was first referred as ‘water poison’associated with flying insects in a Chinese medical encyclopedia in 992 from the Jin Dynasty (265-420 AD). The word ‘dengue’ is derived from the Swahili phrase Ka-dinga pepo, meaning ‘cramp-like seizure’. The first clinically recognized dengue epidemics occurred almost simultaneously in Asia, Africa, and North America in the 1780s. The first clinical case report dates from 1789 of 1780 epidemic in Philadelphia is by Benjamin Rush, who coined the term ‘break bone fever’ because of the symptoms of myalgia and arthralgia. The term dengue fever came into general use only after 1828. Dengue is a mosquito borne viral disease that occurs in tropical and subtropical areas of the world. Dengue Fever (DF) is commonly known as breakbone fever. It is caused by the dengue virus (DENV), which is transmitted by female Aedes mosquitoes of species Aedes aegypti and Aedes albopictus. The mosquito becomes infected when it bites a person with DENVs in their blood. DENVs are maintained in cycles that involve blood-sucking vectors and vertebrate hosts.
EPIDEMIOLOGY
Dengue is a mosquito borne viral disease that has rapidly spread in all regions of the world in recent years. Due to urbanization, population growth, frequent international travelling, and global warming, the incidence of dengue has increased almost 30-fold in the last five decades. An estimated 400 million dengue infections occur worldwide each year, with about 96 million resulting in illness.[6] Dengue disease is endemic in more than one hundred countries including Southeast Asia, the western Pacific islands, Latin America and Africa. However, the disease has been spreading to new areas, including local outbreaks in Europe and southern parts of the United States. Most people with dengue recover without any problems. The fatality rate is 1–5%, and less than 1% with adequate treatment. Severe dengue is a leading cause of serious illness and death in some Asian and Latin American countries. Dengue inflicts a serious health, social and economic burden on the people of endemic areas.
SIGNS AND SYMPTOMS
Dengue should be suspected when a high fever (40°C/104°F) is accompanied by 2 of the following symptoms during the febrile phase:
• Severe headache
• Pain behind the eyes
• Muscle and joint pains
• Nausea
• Vomiting
• Swollen glands
• Rash
Severe Dengue
A patient enters what is called the critical phase normally about 3-7 days after illness onset. It is at this time, when the fever is dropping (below 38°C/100°F) in the patient, that warning signs associated with severe dengue can manifest. Severe dengue is a potentially fatal complication, due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment.
Warning signs during severe dengue phase include:
• Severe abdominal pain
• Persistent vomiting
• Rapid breathing
• Bleeding gums
• Fatigue
• Restlessness
• Blood in vomit.
If patients manifest these symptoms during the critical phase, close observation for the next 24–48 hours is essential so that proper medical care can be provided, to avoid complications and risk of death.
Dengue cannot spread directly from one person to another, and mosquitoes are necessary for transmission of the dengue virus (DENV). The dengue virus is spread through a human-to-mosquito-to-human cycle of transmission. Dengue is transmitted to humans by the bite of an Aedes mosquito infected with a dengue virus (DENV). The female Aedes mosquito becomes infected when it bites a person who has dengue virus (DENV) in his or her blood. An infected mosquito can then spread the dengue virus to healthy people by biting them.
TREATMENT
There is no specific treatment for dengue fever. Patients should rest, stay hydrated and seek medical advice. Depending on the clinical manifestations and other circumstances, patients may be sent home, be referred for in-hospital management, or require emergency treatment and urgent referral. Supportive care such as fever reducers and pain killers can be taken to control the symptoms of muscle aches and pains, and fever.
Fever reducers and pain killers can be taken to control the symptoms of muscle aches and pains, and fever. The best options to treat these symptoms are acetaminophen or paracetamol.
VACCINE
A partially effective vaccine for dengue fever has been approved and is commercially available in several countries. The vaccine is produced by Sanofi and goes by the brand name Dengvaxia
PREVENTION AND CONTROL
For dengue prevention, traditional method is only restricted to vector control measures. The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for dengue as well as for other diseases that Aedes mosquito transmit. As there is no effective vaccine against dengue, the prevention and control of dengue infections depends largely on preventing man-vector contact. At present, numerous strategies have been adopted to control the spread of dengue vector. These include environmental control, biological control, chemical control, and active case surveillance.
Environmental Control Methods
The environmental control methods include:
• Prevention of mosquito breeding:
o Preventing mosquitoes from accessing egg-laying habitats by environmental management and modification;
o Disposing of solid waste properly and removing artificial man-made habitats that can hold water;
o Covering, emptying and cleaning of domestic water storage containers on a weekly basis;
o Applying appropriate insecticides to water storage outdoor containers;
• Personal protection from mosquito bites:
o Using of personal household protection measures, such as window screens, repellents, insecticide treated materials, coils and vaporizers. These measures must be observed during the day both inside and outside of the home (e.g.: at work/school) because the primary mosquito vectors bites throughout the day;
o Wearing clothing that minimizes skin exposure to mosquitoes is advised;
• Community engagement:
o Educating the community on the risks of mosquito-borne diseases;
o Engaging with the community to improve participation and mobilization for sustained vector control;
Biological Control of the Vector
Biological control methods are targeted against the larval stages of the dengue vector. They include the use of larvivorous fish such as Gambusia affinis and Poecilia reticulate, endotoxin producing bacteria (Bacillus thuringiensis serotype H-14 and Bacillus sphaericus are currently used), and copepod crustaceans. The use of mesocyclops (a copepod crustacean) in the Northern Province of Vietnam led to the eradication of the vector in many areas.
Chemical Control
The chemical control methods include the application of larvicidal insecticides or space spraying. Space spraying may be applied as thermal fogs or as ultra-low volume sprays. Although insecticides such as malathion 4%, fenitrothion 1%, or pirimiphos-methyl have proved to be very effective in many control programmes, mosquito vectors develop different patterns of resistance to them. The World Dengue Day is observed every year on 15 June.
CONCLUSION
Dengue has evolved as a global life-threatening public health concern, affecting around 2.5 billion individuals in more than 100 countries. The doctors should be aware about the varied clinical manifestations of this condition and ensure an early and adequate treatment plan. Future directions to combat this dreadful disease aim at methods of mosquito control, development of vaccine, and antiviral drug regimen.
‘Any error in this manuscript is silent testimony of the fact that it was a Human effort’
Dr. Wahied Khawar Balwan (Assistant Professor, GDC Kilhotran) &
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