ENTOMOLOGICAL FIELD TECHNIQUES FOR MOSQUITO AND SAND FLY

PRAKASH DHAKAL

Public Health Microbiology

Tribhuvan University, Nepal

OBJECTIVES

To operate different equipments in the field for collecting mosquito and sand fly .

INTRODUCTION

Entomological field techniques are generally used in vector-borne diseases.

Vector borne diseases are Malaria, JE,Filariasis,Dengue , Kala-azar etc.

Based on local conditions prevalent; optimum combination of these techniques should be used.

Entomological investigations are important and essential aspect of vector control.

These investigations provide information on vector species , their distribution, density, bionomics and susceptibility/resistance to insecticides for vector control.

These investigations are also useful for the monitoring of potential vectors and their role in disease transmission.

Information collected from entomological surveillance techniques helps in understanding the spatial and temporal changes in vector species, efficacy and effectiveness of vector control measures.

SAMPLING REQUIREMENTS

Vehicle to get around. Good topographical map or at least a plat or city

map. Data sheets. Boots. Dipper, collecting jars, small type net. Water proof marking pens, tape etc. Carrying box or container, ice chest etc. Data logger, GPS

SAMPLING EQUIPMENTS Dipper Pipette Aspirator Flashlight Aspirator Larval Container Bag for extra vials,

pens, labeling tape, etc.

METHODOLOGY For BG-Sentinel trap.

BG- Sentinel trap is generally used for the collection of Aedes type of mosquito.

First of all the trap is held in upright position by three stands in three sides.

Then the electric plug is connected. Then mosquito attracting chemical is placed

in the pocket inside the trap. Then the white colored net is covered from

the top. After that a black colored collection box

along with two successive nets are inserted through the white colored net.

After complete assemblage it is connected with electric source, generally of 12 volt.

WORKING MECHANISM OF BG SENTINEL TRAP

Aedes mosqutio are attracted by the chemical which is placed inside the trap.

The odor of chemical is like the smell of socks which is worn for several days.

Then aedes mosquito gets attached in the black colored collection box .

After attachment the mosquito gets inside the collection box due to the negative pressure created by the fan operating inside the trap.

Then mosquito gets collected inside the net.

For CDC Miniature Light Trap

Developed by CDC for portable collection of mosquitoes and sand flies.

Standard survey tool for mosquito collections.

Operates on 6 volts.

WORKING MECHANISM

After completely assembling the equipment it is connected with the electric source of 6 volt.

The main mechanism for collection of mosquito is attraction due the light emitted by the bulb of this instrument.

This attraction is called Phototrophism.

ANIMAL BAITED NET TRAP

In animal baited technique a net of 5 x 5 x 5 m is taken.

From the ground about 1 feet of space is left for the entry of mosquito in the net.

The net is made such that the mosquito entering the net do not comes out.

Mouth Aspirator

From mouth aspirator resting mosquito is collected.

This aspirator is kept near the resting mosquito and is sucked .

After collecting in the aspirator, mosquito is kept in the paper cup covered with net.

Ovi trap

For ovi trap, about 10-15 ml of clean water is taken in a black colored paper cup and in the edge of that cup a sky blue cloth is kept. After few days eggs of mosquito are seen in the cloth.

WINDOW TRAP COLLECTION (EXIT TRAPS)

Window trap collection is done for those mosquitoes which bites indoor and goes outside for the rest.

HUMAN LANDING CATCHES

In this type of collection technique , humans are directed to keep up their pants or trousers up to the knee and the shirt up to their shoulder. Mosquito is allowed to bite to human . immediately at the instant the biting mosquito is sucked through the mouth aspirator .

Since biting of mosquito may spread the disease if it is carrying organism responsible for disease , so nowadays it is not used.

Sticky paper is placed on the land when sand fly jumps over it , it gets stick on the paper.

STICKY TRAP: SANDFLY

CONCLUSION

Different instruments and techniques were used for the collection of mosquito and sandfly .

FIELD PHOTOS AND VIDEOS :

Sincere thanks to respected Lecturer Dr. Ishan Gautam, Natural History Museum , IOST, TU for showing the breeding sites of vector ( Mosquito) and teaching the techniques of collection ,processing and many others…………….

THANK YOU