ABSTRACT
Objective:To detect and identify filarial parasites in dried blood spots (DBS) collected from domestic cats using high resolution melting real-time PCR (HRM RT-PCR).Methods:A total of 208 DBS were collected from domestic cats in a brugian filariasis endemic areas in Surat Thani Province, southern Thailand. Microfilariae were found in 9 blood slides using Giemsa-stained thick blood film. The extracted DNA from blood spot volumes of 10 and 20 μL DBS with positive filarial parasites in cats were performed using HRM RT-PCR method. The primers were designed based on the partial mitochondrial 12S rRNA gene for identifying Brugia malayi, Brugia pahangi, Dirofilaria immitis. All purified samples were then detected.Results:Using different volumes of 10 μL and 20 μL DBS could easily distinguish filarial parasites and showed similar results. PCR amplicons of Brugia malayi, Brugia pahangi and Dirofilaria immitis were determined at melting peak (temperature) of 75.70 77.46 and 73.56 respectively. All 9 positive DBS samples showed positive Brugia pahangi and similar nucleotide sequences.Conclusions:This HRM RT-PCR method is able to diagnose, identify and discriminate filarial parasites collected from DBS, which is simple and inexpensive compared with other probe-based genotyping methods. Furthermore, this method is useful to survey, prevent and control filariasis.
ABSTRACT
Objective: To detect and identify filarial parasites in dried blood spots (DBS) collected from domestic cats using high resolution melting real-time PCR (HRM RT-PCR). Methods: A total of 208 DBS were collected from domestic cats in a brugian filariasis endemic areas in Surat Thani Province, southern Thailand. Microfilariae were found in 9 blood slides using Giemsa-stained thick blood film. The extracted DNA from blood spot volumes of 10 and 20 μL DBS with positive filarial parasites in cats were performed using HRM RT-PCR method. The primers were designed based on the partial mitochondrial 12S rRNA gene for identifying Brugia malayi, Brugia pahangi, Dirofilaria immitis. All purified samples were then detected. Results: Using different volumes of 10 μL and 20 μL DBS could easily distinguish filarial parasites and showed similar results. PCR amplicons of Brugia malayi, Brugia pahangi and Dirofilaria immitis were determined at melting peak (temperature) of 75.70 77.46 and 73.56 respectively. All 9 positive DBS samples showed positive Brugia pahangi and similar nucleotide sequences. Conclusions: This HRM RT-PCR method is able to diagnose, identify and discriminate filarial parasites collected from DBS, which is simple and inexpensive compared with other probe-based genotyping methods. Furthermore, this method is useful to survey, prevent and control filariasis.
ABSTRACT
House dust mite allergen appears to be a major cause of allergy and asthma in children and adult. Thus control of house dust mites is necessary. The objective of this study were to investigate the acaricidal activity of Permethrin, a safe and effective insecticide against house dust mites comparing with Benzyl benzoate, an acaricide which has been widely used for control of house dust mite. A safe and effective dose of each chemical as well as their residual efficacy when impregnated on fabrics were determined. The result shown that median lethal concentration (LC50) and 95% lethal concentration (LC95) of Permethrin were 6.98 mg/ft2 and 42.49 mg/ft2 respectively while median lethal concentration (LC50) of Benzyl benzoate was 4.55 mg/ft2 and 95% lethal concentration (LC95) was 27.68 mg/ft2. Studied on the efficacy and persistence of chemicals-impregnated fabrics against house dust mites shown that the potency of Permethrin impregnated fabrics dropped to 50% at the second months while the potency of Benzyl benzoate were gradually dropped to 80%, 60% and 50% in second, third and fourth month accordingly. Chiang Mai Med Bull 2002;41(1):43-50.