Dengue Fever is not going to go away! 2017 was a terrible year and one which showed quite clearly that the authorities did not have a grip on the disease. However there are tentative signs that dengue might be loosening its grip on Sri Lanka. So far the numbers are down on 2016. The question is whether this is a temporary respite?
Note; all new edits are in red
STOP PRESS: number of cases on the rise in Western Province
Recently Added: Cases per 000 of the population; see below
In this follow up to my earlier post Dengue Update I am going to analyse the figures on a monthly basis starting with January 2018. Most of what was written in the earlier article still holds true so this post is just about adding current information as it becomes available, together with all new material that is around on the web.
So the format for this post will be as follows:
- Cumulative total cases for Sri Lanka; running total compared with 2015, 2016, and 2017
- The top 10 worst affected districts
Sri Lanka Administrative districts
- Cumulative Total to date: to end June
- 2015: 18,558
- 2016: 34,529
- 2017: 128,017
- 2018: 36,955
2. Top Ten Hotspots as at 31/08/18
- Colombo 7,164
- Batticaloa 4,188
- Gampaha 3,729
- Kandy 2,641
- Kalutara 2,294
- Jaffna 2,284
- Kurunegela 1,839
- Ratnapura 1,735 rising up the chart
- Kalmunai 1,497
- Puttalam 1.354
- While the incidence of dengue in Batticaloa is running at over 7 cases per 000 of the population the number of newly recorded cases is beginning to drop.
- The number of cases continues to rise in Kandy
- You would expect the number of cases to tail off in Jaffna now the dry season has arrived, and it seems to be slowing down now. Discounting 2017 which was a major epidemic year, the number of cases is 500+ up on 2016
- The number of new cases in all western province areas is now on the rise as could be expected now that the monsoon season is in full swing and Ratnapura in particular is showing a steady increase.
There is an interesting document I found which you can also read especially if you are medically inclined about the dengue outbreak in Batticaloa
Apart from the medical information there are 3 interesting points to note re: 2017 and possibly 2018
- Rainfall was higher than normal during the North east Monsoon
- Men were twice as likely to contract dengue as women
- There has been a marked increase in road and infrastructure development in the area
Putting all that together there is a situation where increased rainfall promotes a growth in the mosquito population, building works provide many potential nesting sites for the mosquito and it would be largely men who would be working on the buiding sites and be vulnerable to the dengue mosquito. That would explain the rise and rise of dengue in Batticaloa. It might also explain why Jaffna is seeing a marked increase in dengue cases.
- 2015: 1474 cases
- 2016: 612 cases
- 2017: 5606 cases
- 2018: 4188 cases so far
Looking at the cases reported over the extended monsoon and post monsoon period you can see that in 2016/7 the number of cases was 3687 and that was an epidemic year. The number of cases for the current monsoon period (November to March) stands at 3580; about the same. What will be interesting to see is how the number of cases during the dry season this year compares with last year.
A note on Jaffna
Dengue is starting to surge in Jaffna. A recent report from Jaffna teaching hospital suggested that unclean domestic water storage tanks were the main reason for the increase in cases Jaffna.
Most of the Jaffna dengue cases have been reported from the Karavedy area, where water is in short supply and house occupants are forced to collect water in buckets.
A note on Kandy
Kandy is also suffering: this from the Sri Lankan Sunday Times:
“Officials in Kandy concerned about dengue cases there (2,202 to date this year) plan to get tough over the trail of rubbish that hundreds of daily visitors to the city leave behind them.
The Kandy Municipal Council faces the problem of the streams of visitors leaving behind a mass of empty king coconut shells, yoghurt and ice-cream cups and other plastic receptacles, all ideal containers for stagnant water where dengue mosquitoes can breed, Kandy Hospital Deputy Director Dr. Nissanka Wijewardene said.
“We plan to implement the law very strictly, regardless of whether the neighbourhoods are poor or affluent. This is the only way, it seems, to control dengue in Kandy”, Dr Wijewardene said.
Indifference to hygiene and health care was widespread, the Kandy Municipal Council’s chief medical officer, Dr. Asoka Senarath, said, saying there were 2313 dengue cases in June alone.
“People here discard garbage without bothering to tie the bags. Empty curd pots are thrown in gardens and on roads, and these collect water and become mosquito breeding spots.A radical change in behaviour patterns is needed here,” Dr. Senerath said. Public health officers and volunteers were working hard to raise levels of health awareness and promote disease prevention practices in the Kandy community.
“There should be pro-active surveillance where even if only a couple of people fall ill with dengue from an area the authorities should be able to immediately visit the house, neighbourhoods, conduct cleaning programmes and fumigation,” Dr. Senerath said.”
Cases per 000 of the population
looking at the total number of cases is useful if you are planning for the number of medic, hospital beds, distribution of medication etc. However, to get an idea of the incidence and to be able to compare district with district you need to look at the numbers per 000 of the population; so see below; new table added. This gives a truer picture of where the virus is hitting hardest.
|Census 2012||Population||Cases per 000 2017||rank||Cases per 000 2018 July 21st
What you can see is that in 2017
- The wetter west/south west has the higher rates per 000 of the population; as you may expect with 2 monsoons per year and higher population densities
- but also it highlights the significant growth in the number of cases in the North and East. Jaffna is now becoming a dengue hotspot albeit the number of cases tails off during the dry season and both Batticaloa and Trincomalee suffered major epidemics last year
- Kalmunai was a shock; highest of all! It is a muslim majority city in Ampara district which has a very low incidence of dengue overall. The high number of cases per 000 of the population seems to be restricted to the muslim community. You can speculate on why that might be. Is it because the muslim community is relatively segregated from the rest of Ampara district? Is it because Kalmunai is more urbanised and therefore has a bigger waste disposal problem, more breeding sites? Or is it due to higher levels of population density? Maybe a combination of all three?
For 2018 there seem to be some significant changes: We are now 8 months into the new year and a pattern is beginning to emerge.
- Kalmunai still dominates the data set although evidence suggests that the incidence of dengue is starting to fall
- Batticaloa is now ranked 2; up from 6th last year which many thought to be an epidemic year. Maybe now that the dry season is approaching the number of cases will tail off. We have to wait to see. Just worth noting that in 2016 the total number of cases here was 612!
- Jaffna is now right up there; again this may be a seasonal occurrence and overall the number of cases may start to tail off.
- Keep an eye on Kandy. It has a wetter climate, conditions more suited to the growth of the mosquito population and it is now closing in on Gampaha in terms of total number of cases
- Puttalam ranked 9th in 2017. At the moment it ranks 4th
- Colombo on this table has fallen from 2nd to 5th
- Gampaha ahas fallen out of the worst 5
- Worth noting that Trincomalee is nowhere near as affected as Batticaloa so the question has to be why?
- Galle is no longer a hotspot again it would be good to know what the authorities have been doing here to bring about such a significant fall in the number of cases.
Suggestion: if you are downloading this why not also download the admin districts map and map the top 5 or whatever on a monthly basis to see how the virus moves around and how new hotspots emerge.
To help with that
Just picked this up via a post on facebook; what does it mean? I guess it means that the virus is mutating and given the large number of folks affected in 2017 (and possibly 2018) the health risk from dengue fever is increasing, not decreasing! It isn’t just dengue anymore, it’s dengue with attitude! All the more reason for the authorities and the general public to get rid of the complacency that has typified the approach towards fighting this unpleasant disease.
“The behavior of Dengue Haemorrhagic Fever has changed drastically during the current dengue epidemic. We have encountered lot of children with abnormal disease behavior making it a real challenge to detect and manage the disease. The differences we observed are:
1. Patient entering the critical phase very early in the disease course (like day 2, even in day 1)
2. Commencement of the critical phase before platelet crossing 100,000/microlitre (Sometimes even far above 150,000/microlitre )
3. WBC count remaining high above 5000/microlitre throughout the disease course
4. Abnormally prolonged viraemia where both fever and NS1 postivity continues beyond 7th day of the illness.
5. Settlement of fever early in disease course, but platelets continuing to drop and patient entering critical phase later
6. Presence of Co-infection, mainly LRTI and tonsillitis which is misleading.
7. Abnormally short critical phase where patient enter recovery phase or equilibrium phase early ( Here risk is patient suffering fluid overload due to attribution of changes in parameters to critical phase. However we haven’t encountered prolonged critical phase much)
8. Rapid leaking where patient suffers shock within 12 hours without evidence of bleeding (we had one who suffered shock in 6 hours and had platelet count of 160000 and 9% rise in haematocrit at the time of event.)”