SIRIPHAT INTRAKUN

[SIRIPHAT INTRAKUN]

1. The mosquito dissection method
The mosquito dissection is a method for detecting of Plasmodium parasite in Anopheles mosquitoes by finding oocysts in the midgut and sporozoites in salivary gland of mosquito, including the following steps: Before the mosquitos were dissected, the specie of collected mosquitos will be identified. The mosquito will be anesthetized by freezing at -20 degrees Celsius for 5 minutes. The legs of anesthetized mosquito were then removed from its body and placed on the glass slide. For finding oocysts in the midgut, the anesthetized mosquito was fixed with a needle at the beginning of the abdomen and the abdomen segment number 7 was pulled out of segment number 6 with another needle to get midgut. After that, the oocysts were examined in the midgut under the microscope. Meanwhile, finding sporozoites in salivary gland also uses two needles for fixing the thorax and softly pulling the head part of the mosquito. After this step, salivary gland with 3 lobes will be removed from the body of mosquito and placed on the glass slide which cover with slip to detect the sporozoites under the microscope.

2. Advantage and disadvantage of malaria detection in mosquitoes
2.1 Mosquito dissection
Advantages: This technique has high specificity which allow to directly detect oocysts in the midgut and sporozoites in salivary gland of mosquito under the microscope. It can be used to detect parasites in mosquitoes in epidemic areas. Moreover, it is not expensive as compared to other techniques.
Disadvantages: Because this technique has a low sensitivity, only a few positive samples can be found from a large number of mosquitos collected. It requires the fresh samples. Also, because mosquitos can be dissected one at a time, this technique will take longer period of time. In addition, expertise was required for this technique due to the presence of oocytes and yeast in the samples.
2.2 Immunological technique
Advantages: This technique have high specificity and sensitivity. It is simpler to interpret the results from this technique. Furthermore, it does take longer period of time for detection.
Disadvantages: The expertise was required for this technique. Also, this technique is quite expensive and requires laboratory equipment.
2.3 Molecular technique
Advantages: This technique has the highest specificity and sensitivity compared to other techniques mentioned above. It takes a short time to performed this technique and it does not require the expertise.
Disadvantages: This technique requires laboratory equipment. Therefore, it cannot be used to detect parasites in mosquitoes in epidemic areas, the samples must be transported to the laboratory

3. For malaria detection in mosquitos at the field site, the technique of mosquito dissection is the suitable method for this way because it can be transported the equipment that use for this technique to the field site, especially in the epidemic areas where malaria transmission must be monitored and controlled. This technique also has high specificity to detected oocysts and sporozoites. Therefore, I will use this technique at the field site for screening and then the samples will be transported to laboratory to examine by molecular technique.

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