‘Good’ Mosquitoes to Combat Dengue

In News

• Researchers in Indonesia have found a way to fight disease-bearing mosquitoes by breeding a species of the insect which carries a kind of bacteria that prevents viruses like dengue from growing inside them.

All about the recent research

• Breeding a species of mosquito: Researchers in Indonesia are breeding a species of mosquito which carries a type of bacteria, called Wolbachia that prevents viruses like dengue from growing inside them.
• Reduction in cases: Results show that deploying mosquitoes with Wolbachia reduced dengue cases by as much as 77% and hospitalizations by up to 86%.
• Wolbachia: It is a common bacteria that occurs naturally in 60% of insect species, including some mosquitoes, fruit flies, moths, dragonflies and butterflies.
  • It is not, however, found in dengue-carrying Aedes aegypti mosquitoes.
• Mechanism: The mosquitoes carrying dengue will mate with mosquitoes carrying Wolbachia, which will produce Wolbachia mosquitoes – the ‘good’ mosquitoes. So even if they bite people, it won’t affect them.
• WHO estimates: According to the World Health Organization (WHO), global dengue infections have risen rapidly in recent decades, with about half of the world’s population now at risk. An estimated 100-400 million infections are reported every year.
  • In India itself, over 1 lakh cases of Dengue have been reported. States like Haryana, Uttar Pradesh, Punjab, Kerala, Tamil Nadu, Rajasthan, Delhi, Uttarakhand, etc, have registered the bulk of the country’s cases.

What is Dengue?

• Break bone fever: It is commonly known as break-bone fever is a flu-like illness caused by the Dengue virus.
• Aedes mosquito: It is caused when an Aedes mosquito carrying the virus bites a healthy person.
• Concentration across the globe: This disease is mainly found in the tropical and subtropical regions of the world.
  • Most cases occur in tropical areas of the world, with the population in the Indian subcontinent, Southeast Asia, Mexico, Africa, parts of Central and South America most susceptible to the disease.
• No specific treatment: There is no specific treatment for dengue. Early detection of disease progression associated with severe dengue, and access to proper medical care lowers fatality rates of severe dengue to below 1%.

Causes of Dengue

• Various viruses: Dengue is caused due to four viruses, namely – DENV-1, DENV-2, DENV-3, and DENV-4.
• Spread: The virus enters a mosquito when it bites an already infected person. And the illness is spread when it bites a healthy person, and the virus spreads through the person’s bloodstream.
• Immunity: Once a person recovers, he is immune to the specific virus and not the other three types.
• Dengue Haemorrhagic Fever: The probability of developing severe Dengue fever, also known as Dengue Haemorrhagic Fever, increases if you’re infected a second, third or fourth time.

Symptoms of Dengue

• Dengue causes a fever of 104 F degrees along with at least two of these symptoms:
  • Headache, Muscle, bone and joint pain, Nausea, Vomiting, Pain behind the eyes, swollen glands, Rash.

Diagnosis and Treatment

• Diagnosis of dengue infection is done with a blood test.
• There is no specific medicine to treat dengue infection.
• The dengue vaccine CYD-TDV or Dengvaxia was approved by the US Food & Drug Administration in 2019, the first dengue vaccine to get the regulatory nod in the US.

Factors that lead to prevention of the spread of the disease

• Prevention of mosquito breeding by environmental management and modification
• Personal protection from mosquito bites: Using personal household protection measures, such as window screens, repellents, insecticide-treated materials, coils and vaporizers. 
• Community engagement: Educating the community.
• Reactive vector control
• Active mosquito and virus surveillance

Government initiatives for Dengue

• Long Term Action Plan: Developed a Long Term Action Plan for Prevention and Control of Dengue in the country.
• National guidelines: for clinical management of Dengue Fever, Dengue Hemorrhagic Fever, and Dengue Shock Syndromehas.
• Established Sentinel Surveillance Hospitals: with laboratory support for augmentation of diagnostic facilities for Dengue in endemic States.
• Free of cost diagnosis: Diagnosis of Dengue and Chikungunya is provided to the community free of cost.
• National Dengue Day: is observed in India on May 16 with the recommendation of the Ministry of Health and Family Welfare to create awareness about dengue; and to intensify preventive measures and preparedness for the control of disease in the country before transmission season starts.

Way Forward/ Suggestions

• Collaborating network of laboratories: support countries in the confirmation of outbreaks through its collaborating network of laboratories.
• Technical support and guidance: Countries should provide technical support and guidance to each other for the effective management of dengue outbreaks.
• Improve their reporting systems: countries should improve their reporting systems and capture the true burden of the disease.
• Training on clinical management: WHO should provide training on clinical management, diagnosis and vector control at the country and regional level with some of its collaborating centres.
• Legislation: Governments should formulate evidence-based strategies and policies.
• Global Vector Control Response: WHO should support countries in the development of dengue prevention and control strategies and adopting the Global Vector Control Response.

Source: TH