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Upcoming Dengue threat

  • Published at 09:02 pm March 21st, 2020
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A non-gendered climate-sensitive disease in Bangladesh

The infectious disease COVID 19 or commonly known as Coronavirus has now landed in Bangladesh. The next infectious disease ie Dengue is preparing for the monsoon season to wave through Bangladesh. Dengue has been a common bio-hazard in Bangladesh over the last 20 years. The dengue outbreak first impacted the country in 2000; it has more or less been present since. But in 2019, the country experienced one of the largest outbreaks of Dengue disease to date. 


Figure 1: Case study findings of Relationship between number of days of being affected and the financial costings of Dengue in Dhaka City

A case study on the extent of the Dengue problem was conducted by FOREWARN Bangladesh. The study intended to identify the magnitude of the problem in Bangladesh as well as capture the difficulties faced by the patients and family members due to Dengue. Through discussion with several respondents, the study had identified that one of the major problems faced by them was the financial crises. The cost incurred to the families varied widely from 200 taka to 10 lacs depending on two factors- (a) admission to the hospitals and (b) duration of the diseases.

The challenges faced by the patients were lack of doctors and trained nurses; adequate beds in the hospitals; dengue testing kits in the market, etc. However, a common issue faced by patients was that, though free treatment was declared for dengue patients in the government-run hospitals, private hospitals were charging a handsome amount from the patients.

Geographical distribution of Dengue

Cases of Dengue were found throughout the country. In 2019 it was reported that 101,354 patients were affected by the disease. This information was gathered through 41 government and non-government hospitals in Dhaka and other information sent by the relevant civil surgeon offices from those constituencies across Bangladesh. Divisional distribution in the following pie chart shows very apparently that Dhaka is at the highest risk consisting of more than 50% of all other divisions followed by Khulna and Chittagong (Source: Health Emergency Operations Centre and Control Room).


Figure 2: Divisional Distribution of Dengue in 2019 (Source: Health Emergency Operations Centre and Control Room)

Seasonal feature of Dengue disease

The study identified a correlation between seasonal variation and dengue outbreak. It is found that the distribution of dengue patients admitted in the hospital becomes the highest in the month of August. The average pattern shows a very important insight of the temporal distribution of dengue cases ie, the lowest number of cases occur during the dry season, through the end of pre-monsoon and the numbers of patients peak during the monsoon.

Climate change on the Dengue cases

The pre-monsoon rain between March-May fills up possible containers (e.g flower pots, tanks, buckets, cans and bottles) in which Aedes aegypti and Aedes albopictus lay eggs with consequent population increase; patients numbers remain high until the rainy monsoon season (June-October) and decrease gradually afterwards. There are several works of literature available, having a very strong correlation between the number of dengue cases with cumulative rainfall, maximum temperature and humidity. This study, however, found no correlation between a number of admitted patients and humidity. 

It was found that the monthly average rainfall in 2019 during the monsoon season (JJAS) was lower than previous 19 years (2000-2019) but the initial months of the year before the monsoon onset were much better than the previous year’s average. Also, comparison between the average maximum temperature of 2019 and the previous 19 years shows that the highest temperature of each of the month was equivalent to the monthly maximum average temperature of 2019. This shows that with the impact of climate change the temperature of the region is continuously increasing and it has been affecting the monsoon period in the country. And this is heavily influencing the impact of dengue in the country. With the increase in the timeframe of monsoon season and rainfall, there has been a rise in the number of dengue patients in the country. 

Figure 3: Monthly average rainfall in 2019 during the monsoon season (JJAS) was lower than previous 19 years’ average (2000-2018) but the initial months of the year (JFMA) before monsoon onset were much wetter than the previous years’ average.

Figure 4:  Monthly average temperature in 2019 during the compared previous 19 years’ average (2000-2018) but the initial months of the year (JFMA) before monsoon onset were much wetter than the previous years’ average.

Figure 5: Monthly total cases of dengue patient in 2019 and average number of monthly patient from 2000-2018

The correlation between increase of dengue patients with cumulative temperature and rainfall shows that if climate is changing for better or worse it will have a strong impact on the prevalence of dengue in the country. Simon Hales and their colleagues (2002) showed that at current population growth 35% world population is at risk of dengue whereas this percentage could be 50% population if the climate change is considered.

Gender and age dimension of Dengue

Dengue is a non-gendered disease which can affect men and women equally. There has been no correlation found between the sex of patients and Aedes mosquito virus transmission. According to WHO, there is no discrimination of the age group because all age groups are at risk. A recent population-based study reported no sex difference in dengue seroprevalence in Dhaka (ICDDRB, 2012). 

Way forward: Actions to tackle Dengue 

The Government of Bangladesh has taken many actions to reduce the impact of dengue in the country. But there are still many gaps existing. Some of the interventions that were identified from the study are: 

1.    Epidemiological Surveillance

2.    Outbreak Response 

3.    Capacity Building 

4.    Behaviour Change

5.    Inter-sector Collaboration 

6.    Monitoring and Evaluation 

From the above intervention options, it can be summarized that there has been ample scope for improvement in the following areas of early action, coordinated surveillance, and rapid response.

Ashraful Haque is a system analyst. He has been working as Senior Research Officer at ICCCAD. Also, he is working as Coordinator of FOREWARN Bangladesh

Marwa Tasnim, Partnership Officer, International Centre for Climate Change and Development (ICCCAD) has a research focus on Climate-induced Disaster, Management Options and Resilience