Dengue, a viral disease, has become widely prevalent in Tamil Nadu, including in Coimbatore. It has become a dreaded disease because of its virulence and its potency to put the infected people at grave risk.
On the direction of KG Hospital Chairman Dr G.Bakthavathsalam, an overview of dengue was recently presented by Dr Shikha Ranjan, Consultant Microbiologist and Infection Control Officer of KG Hospital, for the post-graduate students in the hospital Auditorium recently.
Quoting the World Health Organization report, Dr Shikha Ranjan said that on an average, annually 400 million dengue infections and 22,000 dengue-related deaths are occurring globally. An estimated 5 million people with severe dengue require hospitalization every year and about 2.5 per cent of those affected dies.
The distribution of dengue cases (as per 2015 statistics) across India is a cause for concern. Tamil Nadu happens to be one of the States with high rate of infection, say above 1,500. In the above mentioned period, Delhi reported the highest number of dengue cases –15,652, followed by Punjab – 8,342 cases, Haryana – 5,452, Karnataka – 4,158 and Gujarat – 3,569.
(According to Tamil Nadu Health Department’s statistics, from 2013 to March 5, 2017 dengue had claimed 21 lives).
Day time predator
According to Dr Shikha Ranjan, dengue is spread by Aedes aegypti, a day biting mosquito that breeds in artificial clean water near human dwelling. The pathogenesis is as follows: infection is transmitted by Aedes aegypti.
The female mosquito of the species acquires the virus by feeding upon viremic human. The extrinsic incubation period is 8-14 days, and the mosquito remains infective for life, say 1-3 months. The infected mosquito in turn introduces the virus into a new host and the virus multiplies in the reticuloendothelial system and enters the blood circulation (viremia).
The Infection Control Officer further says that the onset of dengue causes high fever (saddle-back fever), headache, muscle and joint pain, persisting vomiting, difficulty in breathing, diarrhea, and maculopapular rash. Dr Shikha Ranjan explains saddle-back fever as a fever that subsides after 3 days but comes back by the fifth day.
Strangely, the Aedes aegypti prefers victims with type ‘O’ blood, gym junkies, people who exhale more gas—such as pregnant women and overweight people, and those dressing in dark colours.
- According to the severity of the disease, dengue can be broadly classified into three categories: Classic Dengue/Dengue Fever; Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS).
Dengue Hemorrhagic Fever is a serious life-threatening condition that mostly affects children. Its symptoms are abdominal pain, vomiting, bleeding from the nostrils (epistaxis), vomiting blood (hematemesis) and reduced platelet count.
According to Dr Shikha Ranjan, the fatality rate with DHF is in the range of 10-40%, but can be reduced to less than 1% with prompt treatment.
When the DHF progresses to circulatory collapse, fall in blood pressure, collapsing pulse and cold extremities, such a condition is called Dengue Shock Syndrome (DSS). Dr Shikha Ranjan noted that there is no specific medication for the disease; however, fluid replacement therapy is the mainstay of the treatment.
Drugs to be avoided
Paracetamol and tepid sponge for high fever is recommended. However, aspirin and non-steroid anti-inflammatory drugs (NSAIDs) should not be given. If hematocrit (the ratio of volume of red blood cells to total volume of blood) decreases to more than 40% in children and adult females, and, more than 45% in adult males, blood transfusion should be done.
She cautions that if hemorrhagic manifestations are positive, intramuscular injections should not be given. Quoting the Indian Council of Medical Research (ICMR) sources, Dr Shikha Ranjan said that considering the severity of vector-borne diseases, a nationwide “burden study” has been launched to map the incidence of dengue, chikungunya and Japanese encephalitis.
Dr Shikha Ranjan has suggested the following preventive measures: do not keep empty tins, bottles, buckets and drums around. Turn them upside down so no water will stagnate in them. Remove any old tyres lying on the premises, and make a point to close the water-filled drums with lids. And eliminate all mosquito breeding areas.
Inside the houses, use mosquito repellants; use long sleeved clothes, mosquito nets for beds, mosquito screens on doors and windows. Air-conditioned rooms, by virtue of their doors and windows closed, will give a semblance of protection from lethal mosquito bites.
“Remember that if mosquitoes breed, you will bleed, and therefore promptly take appropriate preventive measures,” Dr Shikha Ranjan added.