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- Kittayapong, P, et al.
(författare)
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Efficacy of permethrin-impregnated clothing on knock-down and mortality of dengue mosquito vectors
- 2015
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Ingår i: Tropical medicine & international health. - : Wiley-Blackwell. - 1360-2276 .- 1365-3156. ; 20:Suppl. 1, s. 110-110
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: As vector control for dengue has proven to be elusive, additional methods to protect against dengue are urgently needed. We have previously shown that pre-fabricated clothing impregnated with permethrin in a proprietary manner had a close to 100% 1 h knock-down and 24 h-mortality effect on Aedes mosquito vectors. However, this effect rapidly declined with repeated washing. Here we investigated different impregnation techniques to assess the best method with the lowest waning efficacy after washing. Materials and methods School clothes were impregnated with permethrin by two different technologies: pad-dry-cure versus exhaustion. Impregnated products were tested for their efficacy using laboratory-reared Aedes mosquito vectors using WHOPES cone test, before and after 10 washes.Results: The 1 h knock down effect and 24 h mortality rate of school clothes treated by both technologies were both found to be 100%. However, the clothes treated by pad-dry-cure technology could stand frequent washing better than those treated by exhaustion technology. The decrease in efficacy of up to about 60% of the clothes treated by pad-dry-cure technology was observed after washing 8 times while those treated by exhaustion technology showed decrease in knock-down effect (67.27%) and mortality rate (74.29%) after washing only 4 times.Conclusion: The knock-down and 24 h mortality results look very promising to support impregnated clothing as a potential strategy to protect against day-biting Aedes mosquito vectors to prevent dengue infections. However, rapid waning efficacy of impregnated clothing after <10 washes suggests that impregnation techniques for sustainable effect are sub-optimal and hence such an approach is not recommended at this point in time. Either new impregnation technologies will need to be developed to overcome the waning efficacy after washing, or clothing such as aprons or vests will need to be employed. Since school aprons are hanged in classrooms after daily use without washing through out the school term, they could potentially have a prolonged impact of permethrin on mosquito vectors (in terms of knock-down and mortality) and eventually dengue transmission in school.This research was funded by the European Union 7th Frame- work Programme through ‘DengueTools’ and Mahidol University.Disclosure: Nothing to disclose
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| 2. |
- Pahumunto, N., et al.
(författare)
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Aggregatibacter actinomycetemcomitans serotypes and DGGE subtypes in Thai adults with chronic periodontitis
- 2015
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Ingår i: Archives of Oral Biology. - : Elsevier BV. - 0003-9969 .- 1879-1506. ; 60:12, s. 1789-1796
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Tidskriftsartikel (refereegranskat)abstract
- © 2015 Elsevier Ltd. All rights reserved. Objective To investigate the distribution of Aggregatibacter actinomycetemcomitans serotypes and DGGE subtypes among isolates from Thai chronic periodontitis patients. Design Forty-four adult Thai periodontitis patients were assessed by a full mouth recording for CAL, PPD, and BOP. Seventy-nine strains of A. actinomycetemcomitans were isolated from deep pockets on selective TSBV agar and 17 strains were isolated from shallow pockets. The strains were serotyped using PCR and subtyped using DGGE. Results The prevalence of A. actinomycetemcomitans was 84.1%. Non-serotypeable A. actinomycetemcomitans strains occurred equally frequent as serotypeable (54.5%); serotype a 18.2%, serotype c 15.9%, serotype e 9.1%, and serotype f 11.4%. Serotype b and d were not detected. A JP2 like strain but serotyped as c was isolated from two patients, and another two strains showed an 886 bp insertion on the ltx promoter of their A. actinomycetemcomitans isolates. DGGE typing disclosed 16 different subtypes among the non-serotypeable strains. Two of them (NS1 and NS2) were more common (12.7 and 10.1%) among the strains than the other 14 subtypes (<5.1%). Most patients showed only one subtype (32.4%) but 29.7% had 2 and 3 different subtypes while 8.1% revealed 4 subtypes in one and the same deep pocket. Conclusion This study showed a greater subtype diversity of A. actinomycetemcomitans predominated by non-serotypeable strains than previously reported in an adult Thai population. It was also revealed for the first time that isolates with a 530 bp deletion or 886 bp insertion of the ltx promoter were serotyped as serotype c.
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