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References
1. Development of malaria diagnosis in Anopheles mosquitoes, ppt, Asso. Prof Dr.Jiraporn Ruangsittichai , Ph.D
2. PCR-based detection of Plasmodium in Anopheles mosquitoes: a comparison of a new high-throughput assay with existing methods, Chris Bass,et al, Malaria journal,15 September 2008.
3. Fast and robust single PCR for Plasmodium sporozoite detection in mosquitoes using the cytochrome oxidase I gene, Diego F. Echeverry,et al, Malaria journal, 31 May 2017
4. A comparison of PCR and ELISA methods to detect different stages of Plasmodium vivax in Anopheles arabiensis, Allison L. Hendershot,et al, Parasite & Vector journal, September 2021 -
If the resources are available, I will use the molecular techniques for malaria detection in mosquitoes as the first priority. Although midgut dissection for finding oocyst and sporozoites is recognized as gold standard, it requires skilled personnel, time consuming and cannot specify the species yet. In concerning with immunoassay such as Slot blot immunoassay: ECL SB and CSP ELISA, although CSP ElISA has many advantages such as robustness and cheapness, and recognized as most widely used methods, there are several reports that CSP ELISA overestimates the true salivary gland infection rate. Furthermore, it is relatively insensitive to low-level infection.
Molecular techniques such as nested PCR,PCR-RFLP, MALDI-TOF MS, and COX-I PCR have higher sensitivity than the other techniques (can detect in less than 10 sporozoites per µL), less time consuming, require least expert among the available techniques, and can determine the specific species. As the drawbacks, it has the limited Plasmodium life-stage specificity in comparing with mosquito dissection and CP ELISA methods. Among the PCR methods, COX-I PCR is is more sensitive, less expensive, and faster than other PCR methods.
In brief, it will be best if the conjunction use of these three methods depending on the situation. As an example, PCR method and CSP ELISA can use in combination for the detection of low-density infections within a mosquito and confirmation of positive infectious mosquitoes. -
Q.1. What is the importance of this study?
Answer; According to the previous data, Angiostrongylus sp. was known to transmit by consuming the raw or improperly cooked land snails that containing infective larvae. The study indicated that houseflies can be a transport host of Angiostrongylus spp. Thus, humans may become infected with angiostrongyliasis without consuming infected, second intermediate hosts due to the houseflies. For prevention, community health education about the prevention of food contamination of flies is as important as proper sanitation and hygienic preparation practices.Q.2. What is the transmission route of Angiostrongylus sp. (from this study)?
Answer; For transmission route, agent is Angiostrongylus sp., definitive and intermediate hosts are snails and slugs, and the houseflies are transport host.
For life cycle, the environment of the study area is a good habitat for definitive and intermediate host. Living area and the waste area are closed, and there is a poor practice on food waste disposal occurred. The houseflies fed on dead, infected snails and slugs, or slime of them. And also on the other paratenic hosts such as crabs and prawns. Then the houseflies rested on the floor and wall of the canteen and camp.And, rested and fed on the food.The people can be infected by eating this contaminated food. Poor waste disposal practice such as uncovered bin are the supporting factor for this condition.3. What are the factors needed to successfully help the houseflies in the process of disease transmission?
Answer; The factors needed will be as follows- (1) the environment of the study area, houseflies can rest and fed on the slime and dead remains of snails and slugs which are abundance in this area. (2) Site plan of the area, canteen and kitchen are close to each other, (3) poor waste disposal practice, such as uncovered bins, and (4) poor food maintaining practices- such as food are not covered properly, and (5) poor food handling and preparation practices- utensils, and floors and walls are not clean properly.
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