Dengue Survey

Vector control day !!!!!!!!!! =)

today we will be following the health inspector and round the village in Naka. so at 8am we reached the District Health Office and were shortly briefed by Mr. Azlan.

The common vector control measured taken are as below :

1. fogging
2. ULV(ultra low volume)
3. Larvasiding
4. Abate

These were the methods used mainly for Dengue as it is the priority vector borne disease. for example fogging is only useful only in dengue and not for malaria.

As the authorities received the call from the medical health center (for the disease surveillance will be discussed on another post, please do refer to the post for the types of disease which were supposed to report on within 24 hours and which need more time), preventive measured will be taken based on the diagnosis made by the medical practitioners.

if more than 1 case are report at the same area, the place is defined as an outbreak area and will be managed as in the protocol (as for this, it will be mentioned together with the post on disease survelliance). The coverage of the fogging is as below :

1. if only 1 case is report in the area,then fogging will have to cover 200m radius.
2. if more than 1 case or if there is extra time then they will have to cover 400m radius.

Fogging will cover 8 houses per charge, but ULV can cover 80 houses. However both of these are usually used together to increase the effectiveness.  

Fogging

for 1 charge (covering 8 houses per time) : 200ml of Sumithion (poison) + 4L of diesel (of which 1L is used for the machine function).

two type: oil based and water based.

usually after notification,they will fog within 1 day.
second fogging will be done one month later.

According to Mr. Azlan, fogging helps only in reducing 20% of Dengue case as it only kill the effective mosquito instead of clearing all of it. Besides, the authorities did not encourages frequent fogging as it could :

1. caused resistant to the poison
2. killing of the insect which could indirectly affecting the farming activites.
3. harmful to human and animals for the poison used.
4. inadequate budget
5. only useful for Dengue and not for malaria and filariasis.

Adding to it's disadvantages, fogging could not done during :
1. windy day
2. early in morning
3. late in evening
4. rainy day

Abate will put in the breeding area,eg: tyres, pots and any stagnant clear water places. Usually will last for 3 month. 

Actually finding the cause is more important than temporarily like fogging.Thus, disease surveillance MUST cover up to 50% of the total house in the area (the more the better). The reason why is because like mentioned above, fogging only killed effective mosquito and this only reduced 20% of the total cases reported. Instead of fogging, it was actually the gotong-royong that clean the breeding site. however, even after repeated reminder to the villagers, it seems like fogging was preferred over gotong-royong. It was said with fogging, they felt more relieved.

Even so, the surveillance still done 3 months once. During this , the group is divided into smaller groups and will be rounding the area according to the map and houses distributed. With this, they will be able to cover most of the houses and the work seems easier.

The target for Dengue is 4 cases per team.

Mr.Azlan also explained about Malaria. Two species are more common in Kedah which are Plasmodium falciparum and Plasmodium vivax. Usually preventive measures focus more in foreigner places especially in FELDA areas.

The surveillance for Malaria and filariasis will be done at night and will be done 3 months once together with the surveillance done for Dengue. Total of 3 times per year . No target mentioned for malaria.

Instead of fogging here, focal spray ( potassium Trioxide, K03 powder) are used and medicated mosquito net were given. Fogging are not used for the Anopheles type of mosquito. Fogging usually used for Aedes transmitted disease.

The next day,the inspector kesihatan vector control crew was bringing our group to Kampung Naka to see how the the sampling of larva done in dengue area.We are separated into 4 team, each team led of by 2 pegawai kesihatan. The distribution of the team is according to the allocation of the places according to the map. included below is the map :

The distribution of the site is to increase the coverage of the houses (like mentioned before the coverage of at least 50% of the total house per surveillance ).

We were told to look around the houses for possible breeding site, for examples flower pot,bottles, pales and tyre. It is said that the mosquito loves to breed in tyres more compare to pots for the reason below :
1. it is darker in the tyres - black in color
2. the water is cleaner

 For each sample , at least 5 larvae are required to have the test positive. The larva were collected by pipet into small bottles. These larva will send to lab to be examined.

once they detect more than 5 larva which belongs to family of Aedes, the house owner will be compound for RM500.00 per each test tube. They will be given 1 month to pay the compound, and failure to do will be summoned by court. However, warning is given out first before they gives the notice.

 Thats all for the day.

- Tan Shin Wuei and Jolyn Ch'ng