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. Will the number of new cases drop back from the 2017, highs or will dengue fever become even more entrenched?
Note; all new edits are in red
STOP PRESS: Another epidemic in Batticaloa ?
Just Added: Cases per 000 of the population; see below
Watch this space
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 April
- 2015: 14.956
- 2016: 19,083
- 2017: 61.597
- 2018: 20,543 lower than 2017 BUT still up on earlier years
2. Top Ten Hotspots as at 31/05/18
- Colombo 3,271
- Batticaloa 3,020 ***** Alarm bells should be ringing
- Gampaha 1,657
- Kandy 1,369
- Jaffna 1,330
- Kalutara 1,302
- Kalmunai 1,224
- Kurunegela 1,190
- Puttalam 1.072
- Ratnapura 893 the number of new cases seems to be accelerating
The key stat here is for Batticaloa. In May Batticaloa has had more reported cases than Colombo for the second month running!!!
- Batticaloa jumps above Gampaha to 2nd and it looks like they have another epidemic on their hands
- Already the incidence of dengue in Batticaloa is running at nearly 5 cases per 000 of the population. Only the muslim enclave of Kalmunai is worse
- The number of cases jumped significantly in Kandy
- Interestingly, although Colombo has the highest total number the figures are well below the number of cases for the first three months in 2017 and 2016 and figures for Gampaha are also lower.
- Overall at 20,083 cases the figures are well down on 2017 but still higher than either 2016 or 2016
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: 3159 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 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.
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 May 31st||rank|
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 5 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
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.)”