3.Comparison of microscopy and PCR for the detection of human Plasmodium species and Plasmodium knowlesi in southern Myanmar
Han Zar Thu ; Han Thwe Kay ; Aye Hla Kyin ; Hlaing Thaung ; Thant Zin Kyaw ; Vythilingam Indra
Asian Pacific Journal of Tropical Biomedicine 2017;7(8):680-685
Objectives: To determine the distribution of Plasmodium (P) species including Plas-modium knowlesi and to compare the specificity and sensitivity of microscopy with nested PCR in malaria diagnosis. Methods: The study was conducted in Kawthaung, southern Myanmar. Ninety clinically suspected malaria patients were screened for malaria by Giemsa stained microscopy and confirmed by nested PCR. Results: Among the participants, 57 (63.3%) were positive and 33 (36.7%) were negative by microscopy. Of positive samples, 39 (68.4%) were Plasmodium falciparum, 17 (29.8%) Plasmodium vivax and 1 (1.8%) Plasmodium malariae, whereas 59-amplified by PCR were 40 (67.8%), 18 (30.5%) and 1 (1.7%) respectively. PCR amplified 2 mi-croscopy negative samples. Two samples of P. falciparum detected by microscopy were amplified as P. vivax and vice versa. All samples were negative for Plasmodium ovale, P. knowlesi and mixed infections. Microscopy had a very good measure of agreement (k= 0.95) compared to nested PCR. Sensitivity and specificity of microscopy for diag-nosis of P. falciparum were 92.5%(95%CI:79.6–98.4) and 96.0%(95%CI:86.3–99.5) respectively, whereas for P. vivax were 83.3%(95%CI:58.6–96.4) and 97.2%(95%CI:90.3–99.7). Conclusions: P. knowlesi was not detected by both microscopy and PCR. Giemsa stained microscopy can still be applied as primary method for malaria diagnosis and is considered as gold standard. As to the lower sensitivity of microscopy for vivax malaria, those with previous history of malaria and relapse cases should be diagnosed by RDT or PCR combined with microscopy. Inaccuracy of species diagnosis highlighted the requirement of training and refresher courses for microscopists.
4.Zika virus and its potential re-emergence in Malaysia
Jamal I-Ching Sam ; Yoke Fun Chan ; Indra Vythilingam ; Wan Yusoff Wan Sulaiman
The Medical Journal of Malaysia 2016;71(2):66-68
Zika virus (ZIKV) has re-emerged to cause explosive
epidemics in the Pacific and Latin America, and appears to
be associated with severe neurological complications
including microcephaly in babies. ZIKV is transmitted to
humans by Aedes mosquitoes, principally Ae. aegypti, and
there is historical evidence of ZIKV circulation in Southeast
Asia. It is therefore clear that Malaysia is at risk of similar
outbreaks. Local and international guidelines are available
for surveillance, diagnostics, and management of exposed
and infected individuals. ZIKV is the latest arbovirus to have
spread globally beyond its initial restricted niche, and is
unlikely to be the last. Innovative new methods for
surveillance and control of vectors are needed to target
mosquito-borne diseases as a whole.
Zika Virus
5.First report of mermithid parasitism (Nematoda: Mermithidae) in mosquitoes (Diptera: Culicidae) from Lao PDR.
Indra Vythilingam ; Bonphone Sidavong ; Thim Chan Seng ; Tunkham Phonemixay ; Samlane Phompida ; M Krishnasamy
Tropical biomedicine 2005;22(1):77-9
Unidentified mermithid nematodes were found in the abdominal cavity of three species of Anopheles mosquitoes from LAO PDR. This is a first record of mermithid nematodes in adult mosquitoes from Lao PDR. Two worms were found in each adult host and the infection was more prevalent in the northern region compared to the south.
Culicidae
;
seconds
;
Parasitism
;
Mermithidae
;
First
6. Modified technique of Wolbachia removal from Malaysian Aedes albopictus
Sylvia JOANNE ; Indra VYTHILINGAM ; Nava YUGAVATHY ; Jonathan Inbaraj DOSS
Asian Pacific Journal of Tropical Biomedicine 2014;4(7):557-560
Objective: To develop an artificial and modified Wolbachia removal technique using tetracycline from naturally Wolbachia infected Aedes albopictus (Ae. albopictus) so as to be able to produce generations of Wolbachia free offsprings. Methods: In this study, seven different tetracycline treatment methods were conducted to obtain the best removal method. Four methods focused on larvae tetracycline treatment, one method on both larvae and adult tetracycline treatment and the last two methods on adult mosquito sucrose treatment. Results: All larval tetracycline treatments resulted in either high larvae mortality, sterile F
7.Modified technique of Wolbachia removal from Malaysian Aedes albopictus.
Sylvia JOANNE ; Indra VYTHILINGAM ; Nava YUGAVATHY ; Jonathan Inbaraj DOSS
Asian Pacific Journal of Tropical Biomedicine 2014;4(7):557-560
OBJECTIVETo develop an artificial and modified Wolbachia removal technique using tetracycline from naturally Wolbachia infected Aedes albopictus (Ae. albopictus) so as to be able to produce generations of Wolbachia free offsprings.
METHODSIn this study, seven different tetracycline treatment methods were conducted to obtain the best removal method. Four methods focused on larvae tetracycline treatment, one method on both larvae and adult tetracycline treatment and the last two methods on adult mosquito sucrose treatment.
RESULTSAll larval tetracycline treatments resulted in either high larvae mortality, sterile F0 adult mosquitoes or unsuccessful Wolbachia removal. Treatment of both larvae and adults resulted in reduced larvae mortality, successful Wolbachia removal but slow mosquito fecundity. As for the adult treatment, 1.0 mg/mL as previously published was not able to completely remove Wolbachia in F1 generation whereas 1.25 mg/mL successfully removed Wolbachia from F1 and F2 mosquitoes in 2 weeks.
CONCLUSIONSThis method is different from the previously published methods as it provides an improved Wolbachia removal technique from Ae. albopictus with high egg hatchability, low larvae mortality, increased fecundity and better Wolbachia removal rate.
8. Comparison of microscopy and PCR for the detection of human Plasmodium species and Plasmodium knowlesi in southern Myanmar
Thu Zar HAN ; Kay Thwe HAN ; Kyin Hla AYE ; Kyaw Zin THANT ; Thaung HLAING ; Indra VYTHILINGAM
Asian Pacific Journal of Tropical Biomedicine 2017;7(8):680-685
Objectives To determine the distribution of Plasmodium (P) species including Plasmodium knowlesi and to compare the specificity and sensitivity of microscopy with nested PCR in malaria diagnosis. Methods The study was conducted in Kawthaung, southern Myanmar. Ninety clinically suspected malaria patients were screened for malaria by Giemsa stained microscopy and confirmed by nested PCR. Results Among the participants, 57 (63.3%) were positive and 33 (36.7%) were negative by microscopy. Of positive samples, 39 (68.4%) were Plasmodium falciparum, 17 (29.8%) Plasmodium vivax and 1 (1.8%) Plasmodium malariae, whereas 59-amplified by PCR were 40 (67.8%), 18 (30.5%) and 1 (1.7%) respectively. PCR amplified 2 microscopy negative samples. Two samples of P. falciparum detected by microscopy were amplified as P. vivax and vice versa. All samples were negative for Plasmodium ovale, P. knowlesi and mixed infections. Microscopy had a very good measure of agreement (κ = 0.95) compared to nested PCR. Sensitivity and specificity of microscopy for diagnosis of P. falciparum were 92.5% (95% CI: 79.6–98.4) and 96.0% (95% CI: 86.3–99.5) respectively, whereas for P. vivax were 83.3% (95% CI: 58.6–96.4) and 97.2% (95% CI: 90.3–99.7). Conclusions P. knowlesi was not detected by both microscopy and PCR. Giemsa stained microscopy can still be applied as primary method for malaria diagnosis and is considered as gold standard. As to the lower sensitivity of microscopy for vivax malaria, those with previous history of malaria and relapse cases should be diagnosed by RDT or PCR combined with microscopy. Inaccuracy of species diagnosis highlighted the requirement of training and refresher courses for microscopists.