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Vector Borne diseases: Prevention and management

With 50 million people affected by dengue every year, causing approximately 4 % of death, according to the World Health Organization (WHO) estimates, it is calling for action to minimize illness and deaths from dengue.

Sharbani Banerjee | New Delhi |

Dengue and chikungunya, the most prevalent of vector-borne diseases, are mosquito-borne viral infections common in warm, tropical climates.

Long incessant rain spell inundating parts of India in September end may signal the retreating of the four-month South-West monsoon but it also brings in worry as stagnant water becomes a breeding ground for mosquitoes leading to various vector-borne diseases.

With 50 million people affected by dengue every year, causing approximately 4 % of death, according to the World Health Organization (WHO) estimates, it is calling for action to minimize illness and deaths from dengue.

Dengue and chikungunya, the most prevalent of vector-borne diseases, are mosquito-borne viral infections common in warm, tropical climates. Infection is caused by any one of four closely related dengue viruses (called serotypes) and these can lead to a wide spectrum of symptoms, including some which are extremely mild (unnoticeable) to those that may require medical intervention and hospitalization. In severe cases, fatalities can occur.

However, there is no treatment for the infection but the symptoms that a patient experiences can be managed.

To combat the infection, here are some of the precautionary measures shared by the doctors across hospitals which you need to know.

Dr Rajiv Dang, Senior Director and HOD – Internal Medicine and Medical Director, Max Hospital, Gurugram

Dengue cases are on the rise for sure which is likely because of water accumulation at places and growth in Aedes mosquitoes.

Most of the cases that we are getting are with high-degree fever on day 1 or day 2 and most of them are turning out to be dengue.

The first signs of dengue fever begin four to ten days after a mosquito bite and remain for three to seven days.

There are four dengue virus serotypes (DENV-1, DENV-2, DENV-3 and DENV-4)

Dengue virus can trigger an acute flu-like illness, but the majority of infections only cause mild sickness. This can occasionally progress into severe dengue, which is attributed to the DENV-2 strain. The DENV-2 strain is regarded as the worst. It can result in two or more typical dengue infection symptoms in addition to fever and be lethal.

While there is no cure for dengue, as a precautionary measure, you can make adjustments to your home and lifestyle.

Apply mosquito repellent, even at home, wear long-sleeved shirts and trousers when outdoors and get rid of stagnant water at home.

Dr Ajay Agarwal, Director and HOD, Internal Medicine, Fortis Hospital Noida

Every year during the monsoons, we see a rapid rise in dengue cases. There are majorly four strains of dengue virus. In Delhi, the serotype DENV 2 has been prevalent this year.

Over the years, the case fatality ratio attributed to dengue has declined considerably. However, we need to keep our guard against the disease.

About 1 in 20 people who get sick with dengue will develop severe dengue. If you have had dengue in the past, you are more likely to develop severe disease.

Given the fact that the transmitting vector (Aedes) lives for only 15 days and can fly to a limited distance of around 400 m, the distribution of the disease is closely tied to the breeding and distribution of the mosquito.

The mosquito lays eggs on damp surfaces just above the water line. It breeds in the water collected in the container, coconut shells, flowerpots, water coolers, etc. Thus, people should try to avoid even a small quantity of stagnant water in their immediate vicinity. Using insect repellants while outside and wearing full-sleeved clothing can be additional ways to prevent a mosquito bite.

The symptoms of dengue include high fever, headache, rash, and muscle and joint pain.

Dr Niranjan Patil, AVP  Scientific Business Head – Infectious Diseases, Microbiology; Molecular Biology – Head Biosafety officer, Metropolis Healthcare

Dengue is known to be caused by 4 distinct dengue virus types – Den 1, Den 2, Den 3, and Den 4.

Currently, it is caused by the co-circulation of all 4 Dengue virus types. But increased severity is generally seen with Den-2 type strain. Apart from increased virulence, Den 2 may also manifest as high-grade fever, joint pain, vomiting, altered sensorium and bleeding complications leading to circulatory shock and death in a few cases.

Erratic weather conditions such as increased environmental temperature as a part of global warming, increased rainfall and seasonal changes contribute to an increase in the mosquito population.

The practice of freshwater storage encourages the breeding of Aedes mosquitoes.

Most cases of dengue fever are under-reported, and more than 80% of cases are asymptomatic.

However, prevention is better than cure, and we should start eliminating the mosquito breeding sites such as accumulated fresh water in any form such as lakes, ponds, water tanks, mud pots, buckets, flowerpots, cisterns, discarded tyres or containers, overhead water tanks etc. These should be emptied periodically.

Since dengue-causing mosquitoes are daytime biters, using protective full sleeves clothing is advisable when you’re outdoors. The use of mosquito repellents and bed mosquito nets will help when you’re indoors.

Nowadays, even the Dengue vaccine is also available in India and can be used in selected individuals who had been previously infected with dengue fever at least once. You can consult your physician for more information on the vaccine.

Dr Neeti Pravesh, Consultant – Internal Medicine, Max Super Speciality Hospital, Shalimar Bagh, New Delhi 

This year the monsoon has brought along with the “Dengue Health Crisis” attributed to the “virulent DENV-2” strain in states like Delhi,U.P., Bihar,Tamil Nadu and Maharashtra are witnessing Dengue Fever Outbreak

The DENV-2 strain most prevalent this year is characterized by the early onset of severe symptoms.

For prevention, get children vaccinated between 9-16 years with lab-confirmed preventive dengue infected cases in areas where Dengue is endemic, wear covered clothing, use mosquito repellents and nets and remove stagnant water

Also, as part of treatment, keep yourself hydrated, get plenty of rest, and take pain relief medication like paracetamol, nonsteroidal anti-inflammatory drugs must be avoided, they can increase the risk of internal bleeding.

Dr. Amol Jaybhaye, Consultant (Paediatric Infectious Diseases and Immunology) SRCC Children’s Hospital, managed by Narayana Health

Dengue is caused by a virus of the Flaviviridae family and there are four distinct. The fifth variant DENV-5 was isolated in October 2013. This serotype follows the sylvatic cycle whereas the other four serotypes follow the human cycle. Genetic recombination, natural selection and genetic bottleneck are a few causes of the emergence of the new serotype. Currently, in India, there is no indication of the presence of DENV-5.

Stop mosquitoes from accessing egg-laying habitats by environmental management by removing artificial man-made habitats that can hold water;

Use protection measures, such as window screens, and repellents.

Dr Santosh Kumar Agrawal Sr. Consultant Internal Medicine Marengo QRG Hospital Faridabad

In the case of dengue, there are a few aspects of prevention.

The first one is source reduction which means finding potential mosquito breeding sites like outdoor or indoor water storage containers.

In these storage containers, freshwater should be refilled at least once a week after cleaning it inside.

The second one is the outdoor and indoor use of insecticide sprays. The next preventive aspect is the use of mosquito repellent creams or sprays.

During outdoor activities wear shoes, full sleeve shirt and full pants/trousers

Dr Trupti Gilada, Infectious Disease specialist, Masina Hospital

Dengue has four strains and there isn’t any evidence of a newer strain of dengue that arises since the last strain that we saw in the last two years.

The prevention protocols for all malaria and all mosquito-borne illnesses remain at different levels, which include the government level and the policy level, which includes the prevention of mosquito breeding grounds.

This is the most difficult to tackle. So at an individual level, it’s important to take care of preventing breeding grounds of mosquitoes in and around the house. Keep your windows closed during dusk and dawn to prevent the entry of mosquitoes into the house, wearing full-length clothes, especially when kids are out to play in the evening and use mosquito repellents are the key.