MyMedR

Displaying publications 141 - 160 of 164 in total

Abstract:

Sort:

Fulltext Camellia sinensis solvent extract, epigallocatechin gallate and caffeine confer trophocidal and cysticidal effects against Acanthamoeba castellanii

Fakae LB, Harun MSR, Ting DSJ, Dua HS, Cave GWV, Zhu XQ, et al.

Acta Trop, 2023 Jan;237:106729.
PMID: 36280206 DOI: 10.1016/j.actatropica.2022.106729

We examined the anti-acanthamoebic efficacy of green tea Camellia sinensis solvent extract (SE) or its chemical constituents against Acanthamoeba castellanii by using anti-trophozoite, anti-encystation, and anti-excystation assays. C. sinensis SE (625-5000 µg/mL) inhibited trophozoite replication within 24-72 h. C. sinensis SE exhibited a dose-dependent inhibition of encystation, with a marked cysticidal activity at 2500-5000 µg/mL. Two constituents of C. sinensis, namely epigallocatechin-3-gallate and caffeine, at 100 μM and 200 μM respectively, significantly inhibited both trophozoite replication and encystation. Cytotoxicity analysis showed that 156.25-2500 µg/mL of SE was not toxic to human corneal epithelial cells, while up to 625 µg/mL was not toxic to Madin-Darby canine kidney cells. This study shows the anti-acanthamoebic potential of C. sinensis SE against A. castellanii trophozoites and cysts. Pre-clinical studies are required to elucidate the in vivo efficacy and safety of C. sinensis SE.
Breeding habitat preference of preimaginal black flies (Diptera: Simuliidae) in Peninsular Malaysia

Ya'cob Z, Takaoka H, Pramual P, Low VL, Sofian-Azirun M

Acta Trop, 2016 Jan;153:57-63.
PMID: 26476394 DOI: 10.1016/j.actatropica.2015.10.007

To investigate the breeding habitat preference of black flies, a comprehensive black fly survey was conducted for the first time in Peninsular Malaysia. Preimaginal black flies (pupae and larvae) were collected manually from 180 stream points encompassing northern, southern, central and east coast of the Peninsular Malaysia. A total of 47 black fly species were recorded in this study. The predominant species were Simulium trangense (36.7%) and Simulium angulistylum (33.3%). Relatively common species were Simulium cheongi (29.4%), Simulium tani (25.6%), Simulium nobile (16.2%), Simulium sheilae (14.5%) and Simulium bishopi (10.6%). Principal Component Analysis (PCA) of all stream variables revealed four PCs that accounted for 69.3% of the total intersite variance. Regression analysis revealed that high species richness is associated with larger, deeper, faster and higher discharge streams with larger streambed particles, more riparian vegetation and low pH (F=22.7, d.f.=1, 173; P<0.001). Relationship between species occurrence of seven common species (present in >10% of the sampling sites) was assessed. Forward logistic regression analysis indicated that four species were significantly related to the stream variables. S. nobile and S. tani prefer large, fast flowing streams with higher pH, large streambed particles and riparian trees. S. bishopi was commonly found at high elevation with cooler stream, low conductivity, higher conductivity and more riparian trees. In contrast, S. sheilae was negatively correlated with PC-2, thus, this species commonly found at low elevation, warmer stream with low conductivity and less riparian trees. The results of this study are consistent with previous studies from other geographic regions, which indicated that both physical and chemical stream conditions are the key factors for black fly ecology.
Bleeding manifestations of dengue haemorrhagic fever in Malaysia

George R, Duraisamy G

Acta Trop, 1981 Mar;38(1):71-8.
PMID: 6111919

Analysis of the bleeding manifestations of 130 cases of dengue haemorrhagic fever admitted into the Children's ward of the General Hospital, Kuala Lumpur from May 1973 to September 1978 has been done. Petechial skin rash, epistaxis and gum bleeding were seen most commonly in mild and moderately severe cases. However, blood stained gastric aspirates, and severe haematemesis were seen in severe or very severe cases. Though with better vector control and preventive measures, a marked reduction in the incidence of the cases has been noted, severe cases were seen with symptoms of shock and gastrointestinal bleeding. These symptoms carried a bad prognosis. Among 15 children that died 10 had gastrointestinal bleeding and 2 had a disseminated intravascular coagulation defect. Lymphocytosis with atypical lymphocytes, low platelet count, low reticulocyte count and raised packed cell volume were the main haematological features seen in all these cases. All these features reverted to normal within a week. Mild evidence of disseminated intravascular coagulation was seen in a number of cases, but severe features were seen only in four. Two cases improved as a result of heparin therapy.
Biology and pathogenesis of Naegleria fowleri

Siddiqui R, Ali IK, Cope JR, Khan NA

Acta Trop, 2016 Dec;164:375-394.
PMID: 27616699 DOI: 10.1016/j.actatropica.2016.09.009

Naegleria fowleri is a protist pathogen that can cause lethal brain infection. Despite decades of research, the mortality rate related with primary amoebic meningoencephalitis owing to N. fowleri remains more than 90%. The amoebae pass through the nose to enter the central nervous system killing the host within days, making it one of the deadliest opportunistic parasites. Accordingly, we present an up to date review of the biology and pathogenesis of N. fowleri and discuss needs for future research against this fatal infection.
Bibliometric analysis of schistosomiasis research in Southeast Asia (1908-2020)

Tantengco OAG, Rojo RD

Acta Trop, 2022 Jan 20;228:106322.
PMID: 35065014 DOI: 10.1016/j.actatropica.2022.106322

OBJECTIVES: This study determined the characteristics and trends of published articles regarding schistosomiasis in Southeast Asian countries through a bibliometric analysis.
METHODS: Using the Scopus database, we identified all original research articles on schistosomiasis from 1908 to 2020 from SEA countries: Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam. Bibliographic and citation information was obtained, and visualization of collaboration networks of countries and keywords related to schistosomiasis was conducted using VOSviewer software.
RESULTS: We obtained 528 schistosomiasis articles published between 1908 and 2020 from SEA countries. The number of publications continued to increase and peaked from 2000 until 2020. The Philippines had the highest number of publications (n = 231), followed by Thailand (n = 153), and Malaysia (n = 64). The leading journals with the highest number of publications in this field include the Southeast Asian Journal of Tropical Medicine and Public Health (n = 96), Acta Tropica (n = 27), and Plos Neglected Tropical Diseases (n = 24). The most common keywords related to schistosomiasis research in SEA were "schistosomiasis", "Schistosoma japonicum", "Schistosoma mekongi", "Schistosoma mansoni", and "praziquantel". International collaboration was significantly correlated with scientific productivity for schistosomiasis research.
CONCLUSION: Our study showed the research landscape, trends and development, and collaboration among researchers in schistosomiasis in SEA. Our results also revealed the limited schistosomiasis research in several SEA countries. There is a need for more research to improve our understanding of the epidemiology of schistosomiasis in SEA, which can help in improving the control and prevention of this disease.
Antibodies to Plasmodium falciparum in an indigenous population from a malaria endemic area of Malaysia

Archibald CP, Mak JW, Mathias RG, Selvajothi S

Acta Trop, 1990 Dec;48(2):149-57.
PMID: 1980570

Indirect fluorescent antibody (IFA) tests and enzyme-linked immunosorbent assays (ELISA) were used to measure antibodies to Plasmodium falciparum in an indigenous population in an area of Malaysia with high malaria prevalence. The results of three surveys were analyzed to examine the relation of these serologic measures with age, parasite rate, and spleen size. For children 0-4 years old, increasing spleen size was associated with an increasing likelihood of malaria parasitemia, while for 5-9 year olds the two variables were unrelated. Parasite rate declined with age and ELISA titre increased with age in all surveys; IFA titre was consistently high and did not vary with age. Neither antibody measure was significantly correlated with either the presence or the actual density of parasitemia. These antibody measures are most useful as adjuncts to the more traditional techniques of malaria assessment.
Anti-amoebic potential of azole scaffolds and nanoparticles against pathogenic Acanthamoeba

Walvekar S, Anwar A, Anwar A, Sridewi N, Khalid M, Yow YY, et al.

Acta Trop, 2020 Nov;211:105618.
PMID: 32628912 DOI: 10.1016/j.actatropica.2020.105618

Acanthamoeba spp. are free living amoeba (FLA) which are widely distributed in nature. They are opportunistic parasites and can cause severe infections to the eye, skin and central nervous system. The advances in drug discovery and modifications in the chemotherapeutic agents have shown little improvement in morbidity and mortality rates associated with Acanthamoeba infections. The mechanism-based process of drug discovery depends on the molecular drug targets present in the signaling pathways in the genome. Synthetic libraries provide a platform for broad spectrum of activities due to their desired structural modifications. Azoles, originally a class of synthetic anti-fungal drugs, disrupt the fungal cell membrane by inhibiting the biosynthesis of ergosterol through the inhibition of cytochrome P450 dependent 14α-lanosterol, a key step of the sterol pathway. Acanthamoeba and fungi share the presence of similar sterol intermediate, as ergosterol is also the major end-product in the sterol biosynthesis in Acanthamoeba. Sterols present in the eukaryotic cell membrane are one of the most essential lipids and exhibit important structural and signaling functions. Therefore, in this review we highlight the importance of specific targeting of ergosterol present in Acanthamoebic membrane by azole compounds for amoebicidal activity. Previously, azoles have also been repurposed to report antimicrobial, antiparasitic and antibacterial properties. Moreover, by loading the azoles into nanoparticles through advanced techniques in nanotechnology, such as physical encapsulation, adsorption, or chemical conjugation, the pharmacokinetics and therapeutic index of the drugs can be significantly improved. The current review proposes an important strategy to target Acanthamoeba using synthetic libraries of azoles and their conjugated nanoparticles for the first time.
Anti-amoebic effects of synthetic acridine-9(10H)-one against brain-eating amoebae

Ahmed U, Manzoor M, Qureshi S, Mazhar M, Fatima A, Aurangzeb S, et al.

Acta Trop, 2023 Mar;239:106824.
PMID: 36610529 DOI: 10.1016/j.actatropica.2023.106824

Pathogenic A. castellanii and N. fowleri are opportunistic free-living amoebae. Acanthamoeba spp. are the causative agents of granulomatous amebic encephalitis (GAE) and amebic keratitis (AK), whereas Naegleria fowleri causes a very rare but severe brain infection called primary amebic meningoencephalitis (PAM). Acridinone is an important heterocyclic scaffold and both synthetic and naturally occurring derivatives have shown various valuable biological properties. In the present study, ten synthetic Acridinone derivatives (I-X) were synthesized and assessed against both amoebae for anti-amoebic and cysticidal activities in vitro. In addition, excystation, encystation, cytotoxicity, host cell pathogenicity was also performed in-vitro. Furthermore, molecular docking studies of these compounds with three cathepsin B paralogous enzymes of N. fowleri were performed in order to predict the possible docking mode with pathogen. Compound VII showed potent anti-amoebic activity against A. castellanii with IC50 53.46 µg/mL, while compound IX showed strong activity against N. fowleri in vitro with IC50 72.41 µg/mL. Compounds II and VII showed a significant inhibition of phenotypic alteration of A. castellanii, while compound VIII significantly inhibited N. fowleri cysts. Cytotoxicity assessment showed that these compounds caused minimum damage to human keratinocyte cells (HaCaT cells) at 100 µg/mL, while also effectively reduced the cytopathogenicity of Acanthamoeba to HaCaT cells. Moreover, Cathepsin B protease was investigated in-silico as a new molecular therapeutic target for these compounds. All compounds showed potential interactions with the catalytic residues. These results showed that acridine-9(10H)-one derivatives, in particular compounds II, VII, VIII and IX hold promise in the development of therapeutic agents against these free-living amoebae.
An overview of rickettsiae in Southeast Asia: Vector-animal-human interface

Low VL, Tan TK, Khoo JJ, Lim FS, AbuBakar S

Acta Trop, 2020 Feb;202:105282.
PMID: 31778642 DOI: 10.1016/j.actatropica.2019.105282

Rickettsioses are emerging, and re-emerging diseases caused by obligate intracellular arthropod-borne bacteria that infect humans and animals worldwide. Various rickettsiae such as Orientia, Rickettsia, Anaplasma and Ehrlichia have been circulated in companion, domesticated and wild animals through bites of infected ticks, fleas, lice or mites. This review summarizes the infections of rickettsiae, including the newly discovered regional species Rickettsia thailandii, Candidatus Rickettsia sepangensis, Candidatus Rickettsia johorensis, Candidatus Rickettsia laoensis, Candidatus Rickettsia mahosotii, Candidatus Rickettsia khammouanensis, Candidatus Anaplasma pangolinii, and other novel genotypes in vectors, humans and animals in Southeast Asia. Issues on some unidentified rickettsiae that elicit immune responses and production of antibodies that are cross-reactive with the antigens used are discussed. Knowledge gaps which required attention are also identified in this review.
An ambient temperature stable and ready-to-use loop-mediated isothermal amplification assay for detection of toxigenic Vibrio cholerae in outbreak settings

Engku Nur Syafirah EAR, Nurul Najian AB, Foo PC, Mohd Ali MR, Mohamed M, Yean CY

Acta Trop, 2018 Jun;182:223-231.
PMID: 29545156 DOI: 10.1016/j.actatropica.2018.03.004

Cholera, caused by Vibrio cholerae is a foodborne disease that frequently reported in food and water related outbreak. Rapid diagnosis of cholera infection is important to avoid potential spread of disease. Among available diagnostic platforms, loop-mediated isothermal amplification (LAMP) is regarded as a potential diagnostic tool due to its rapidity, high sensitivity and specificity and independent of sophisticated thermalcycler. However, the current LAMP often requires multiple pipetting steps, hence is susceptible to cross contamination. Besides, the strict requirement of cold-chain during transportation and storage make its application in low resource settings to be inconvenient. To overcome these problems, the present study is aimed to develop an ambient-temperature-stable and ready-to-use LAMP assay for the detection of toxigenic Vibrio cholerae in low resource settings. A set of specific LAMP primers were designed and tested against 155 V. cholerae and non-V. cholerae strains. Analytical specifity showed that the developed LAMP assay detected 100% of pathogenic V. cholerae and did not amplified other tested bacterial strains. Upon testing against stool samples spiked with toxigenic V. cholerae outbreak isolates, the LAMP assay detected all of the spiked samples (n = 76/76, 100%), in contrast to the conventional PCR which amplified 77.6% (n = 59/76) of the tested specimens. In term of sensitivity, the LAMP assay was 100-fold more sensitive as compared to the conventional PCR method, with LOD of 10 fg per μL and 10 CFU per mL. Following lyophilisation with addition of lyoprotectants, the dry-reagent LAMP mix has an estimated shelf-life of 90.75 days at room temperature.
Aedes aegypti(Linnaeus) larvae from dengue outbreak areas in Selangor showing resistance to pyrethroids but susceptible to organophosphates

Leong CS, Vythilingam I, Wong ML, Wan Sulaiman WY, Lau YL

Acta Trop, 2018 Sep;185:115-126.
PMID: 29758171 DOI: 10.1016/j.actatropica.2018.05.008

The resistance status of Selangor Aedes aegypti (Linnaeus) larvae against four major groups of insecticides (i.e., organochlorines, carbamates, organophosphates and pyrethroids) was investigated. Aedes aegypti were susceptible against temephos (organophosphate), although resistance (RR50 = 0.21-2.64) may be developing. The insecticides susceptibility status of Ae. aegypti larvae were found heterogeneous among the different study sites. Results showed that Ae. aegypti larvae from Klang, Sabak Bernam and Sepang were susceptible against all insecticides tested. However, other study sites exhibited low to high resistance against all pyrethroids (RR50 = 1.19-32.16). Overall, the application of synergists ethacrynic acid, S.S.S.- tributylphosphorotrithioate and piperonyl butoxide increased the toxicity of insecticides investigated. However, the application failed to increase the mortality to susceptible level (>97%) for certain populations, therefore there are chances of alteration of target site resistance involved. Biochemical assays revealed that α-esterase, (Gombak, Kuala Langat, Kuala Selangor and Sabak Bernam strains) β-esterase (Klang and Sabak Bernam strains), acetylcholinesterase (Kuala Selangor and Sabak Bernam strains), glutathione-S-transferase (Kuala Selangor and Sabak Bernam strains) and mono-oxygenases (Gombak, Hulu Langat, Hulu Selangor and Kuala Langat strains) were elevated. Spearman rank-order correlation indicated a significant correlation between resistance ratios of: DDT and deltamethrin (r = 0.683, P = 0.042), cyfluthrin and deltamethrin (r = 0.867, P =0.002), cyflyuthrin and lambdacyhalothrin (r = 0.800, P =0.010), cyfluthrin and permethrin (r = 0.770, P =0.015) deltamethrin and permethrin (r = 0.803, P =0.088), propoxur and malathion (r = 0.867, P = 0.002), malathion and temephos (r = 0.800, P = 0.010), etofenprox and MFO enzyme (r = 0.667, P =0.050). The current study provides baseline information for vector control programs conducted by local authorities. The susceptibility status of Ae. aegypti should be monitored sporadically to ensure the effectiveness of current vector control strategy in Selangor.
Advances in research on schistosomiasis and toxoplasmosis in China: A bibliometric analysis of Chinese academic journals published from 1980 to 2021

Tao Y, Shen C, Zhang Y, Zhao X, Leow CY, Wu J, et al.

Acta Trop, 2023 Feb;238:106783.
PMID: 36455636 DOI: 10.1016/j.actatropica.2022.106783

BACKGROUND: The scale-up of zoonoses prevention control and eradication in China, coupled with numerous academic articles in Chinese journals has led to the development of new tools and strategies aimed at further consolidating parasite control goals. As a result, there is a growing need for an up-to-date understanding of the research progress and prevention and control experience of parasitic diseases in China.
METHODS: To understand the research status of schistosomiasis and toxoplasmosis in China, academic articles published in Chinese journals from 1980 to 2021 were retrieved from China National Knowledge Infrastructure (CNKI) and Wanfang databases. The Bibliographic Items Co-occurrence Matrix Builder (BICOMB) software was used to extract and analyze the keyword frequencies. The 'K/A ratio' as the frequency of a keyword that occurred in all the articles within a certain time stage was calculated to compare the popularity of the same keyword in different time stages. Keyword co-occurrence network maps were constructed by VOSviewer software.
RESULTS: A total of 18,508 articles in the research field of Schistosoma and 13,289 articles in the field of Toxoplasma gondii were included. Results in both fields showed some similarities: the annual number of articles presented an increasing trend before entering the 21st century and decreased rapidly in recent years. Two opposite changing trends of keyword frequency could be observed in the K/A ratio analysis: the K/A ratios of 'Surveillance' and 'Infection' continuously increased over time, while those of 'Schistosoma mansoni' and 'Mesenteric lymph nodes' decreased. The diversification of keyword co-occurrence networks could be observed in the co-occurrence network maps.
CONCLUSIONS: This bibliometric analysis reveals trends in research themes in the fields of Schistosoma and Toxoplasma gondii from 1980 to 2021, presenting China's experience such as a high degree of government involvement and multidisciplinary participation in schistosomiasis and toxoplasmosis control and elimination.
A visualized hybrid PCR-LAMP assay for the detection of human Plasmodium species

Lai MY, Ponnampalavanar SSS, Omar SFS, Lau YL

Acta Trop, 2024 Mar;251:107120.
PMID: 38199452 DOI: 10.1016/j.actatropica.2024.107120

Combining the advantages of PCR and LAMP, we described a new technique, namely PCR-LAMP, for malaria diagnosis. The whole process of DNA amplification can be completed in 35 min. This hybrid amplification technique markedly improved the sensitivity of detection compared to the classic single PCR or LAMP assay alone. PCR-LAMP assay had a detection limit of 1 copy/µL for P. knowlesi and P. ovale, 0.1 copy/µL for P. vivax, P. falciparum and P. malariae, respectively. To facilitate the endpoint detection, xylenol orange was added. Positive samples were indicated in orange while negative reactions were violet. The inclusion of xylenol orange into the LAMP reaction mix significantly reduces the post-amplification workload. Without relying on the use of specific instruments, the color changes of the amplicons could be visualized directly through the naked eye. In conclusion, PCR-LAMP poses the potential to be developed as a new malaria molecular diagnosis tool.
A point-of-care cassette test for detection of Strongyloides stercoralis

Noordin R, Osman E, Kalantari N, Anuar NS, Gorgani-Firouzjaee T, Sithithaworn P, et al.

Acta Trop, 2022 Feb;226:106251.
PMID: 34808116 DOI: 10.1016/j.actatropica.2021.106251

Strongyloides stercoralis is a parasite that causes strongyloidiasis worldwide. It may lead to a life-long infection in immunocompetent people and hyperinfection in immunosuppressed patients. A point-of-care (POC) rapid test is helpful for patient diagnosis in resource-limited settings and as a detection tool in elimination/control programs. Previously, we reported a rapid IgG4 dipstick test (Ss Rapid®) for Strongyloides suitable for a laboratory setting. A POC cassette format of the test, which is field-applicable, has since been developed. Here, we report on a laboratory-based evaluation of the Ss Rapid® cas sette test on 285 sera. We assessed the diagnostic sensitivity of the Ss Rapid® cas sette with 32 sera, comprising samples from larval and/or DNA positive individuals from three countries. Additionally, we also tested samples from 33 seropositive endemic areas residents. We evaluated the diagnostic specificity of the test using 220 samples, comprising sera from other infections (n = 101), allergy cases with high IgE antibodies (n = 4), and blood donors (n = 115). The test showed high diagnostic sensitivity (97%, 31/32), and all sera of the seropositive endemic residents were reactive. It also showed high diagnostic specificity (94.5%, 208/220), and all false-positive samples tested negative after sera adsorption using recombinant NIE-coated microsphere beads. Additionally, we showed that the test worked with spiked whole blood samples. The study results showed that the SsRapid® cas sette test merits further laboratory and field evaluations.
A new species of the Simulium (Simulium) variegatum species-group (Diptera: Simuliidae) from Thailand

Takaoka H, Srisuka W, Saeung A

Acta Trop, 2019 Mar;191:155-161.
PMID: 30611713 DOI: 10.1016/j.actatropica.2019.01.002

A new species of black fly, Simulium (Simulium) luculentum, is described from specimens collected in Thailand, and is assigned to the Simulium variegatum species-group of the subgenus Simulium Latreille. This new species is distinguished from most members of this species group in the female by the mid femur and tibia entirely yellowish; and in the pupa by the gill with six filaments, which are somewhat inflated basally. This species represents the fifth member of the S. variegatum species-group recorded from Thailand.
A new species of the Simulium (Gomphostilbia) ceylonicum species-group (Diptera: Simuliidae) from Thailand

Takaoka H, Srisuka W, Ya'cob Z, Low VL, Saeung A

Acta Trop, 2021 May;217:105865.
PMID: 33607063 DOI: 10.1016/j.actatropica.2021.105865

A new black fly species, Simulium (Gomphostilbia) pangsidaense, is described on the basis of adult female, male, pupal exuviae and mature larvae from Pang Sida National Park, Sa Kaew Province, Eastern Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from three Thai members of the S. ceylonicum species-group by the following characteristics: from S. (G.) curtatum Jitklang et al. and S. (G.) sheilae Takaoka & Davies by the wide pupal terminal hooks (triangular terminal hooks in the latter two species), and from S. (G.) sheilae and S. (G.) trangense Jitklang et al. by the number of male upper-eye facets in 13 vertical columns and 14 or 15 horizontal rows (10 or 11 vertical columns and 12 or 13 horizontal rows in the latter two species). This is the fourth member of the S. ceylonicum species-group recorded from Thailand.
A new species of the Simulium (Gomphostilbia) (Diptera: Simuliidae) from Thailand, with its phylogenetic relationships with related species in the Simulium asakoae species-group

Srisuka W, Takaoka H, Fukuda M, Otsuka Y, Saeung A

Acta Trop, 2019 Sep;197:105043.
PMID: 31153893 DOI: 10.1016/j.actatropica.2019.105043

A new species of black fly, Simulium (Gomphostilbia) rampae, is described, based on adult male, its pupal exuviae and mature larvae collected from Doi Inthanon National Park, northern Thailand. This new species is placed in the Simulium asakoae species-group, and is characterized in the male by the high number of upper-eye facets in 17 vertical columns and 18 horizontal rows, in the pupa by the gill with a long common basal stalk, cone-shaped terminal hook, and cocoon with an anterodorsal projection, and in the larva by the medium-long postgenal cleft. A DNA analysis using COI gene supported its assignment to the S. asakoae species-group and showed its close relationship to S. (G.) udomi Takaoka & Choochote and S. (G.) chiangdaoense Takaoka & Srisuka. This is the fourth member of the S. asakoae species-group recorded from Thailand.
A new species of Simulium (Simulium) (Diptera: Simuliidae) from Genting Highlands, Malaysia

Ya'cob Z, Takaoka H, Low VL, Sofian-Azirun M

Acta Trop, 2018 Jun;182:1-3.
PMID: 29453951 DOI: 10.1016/j.actatropica.2018.02.007

Simulium (Simulium) rasuli sp. nov. is described from two females collected by a Malaise trap in Genting Highlands, Peninsular Malaysia. This new species is placed in the Simulium christophersi species-group of the subgenus Simulium. The female of this new specie is characterized by the scutum with three longitudinal vittae, dark legs, claw with a small subbasal tooth, and ovipositor valve triangular with its inner margin nearly straight. This new species is distinguished in the female from all the six named species of the species-group by the entirely brownish-black femora and tibiae.
A new species of Simulium (Gomphostilbia) (Diptera: Simuliidae) from Northern Thailand, with its genetic relationship in the S. asakoae species-group

Srisuka W, Aupalee K, Low VL, Yácob Z, Fukuda M, Saeung A, et al.

Acta Trop, 2021 Jun;218:105889.
PMID: 33722581 DOI: 10.1016/j.actatropica.2021.105889

A new black fly species, Simulium (Gomphostilbia) kiewlomense, is described from females, males, pupae and mature larvae in Thailand. This new species is placed in the S. asakoae species-group and is characterized by having a combination of the elongate female sensory vesicle, widened male hind basitarsus, which is much wider than the hind femur, small pupal terminal hooks, and light greenish larval abdominal segments 1-3. Taxonomic notes are given to separate this new species from other related species. A DNA analysis using the COI gene shows that this new species has two genoforms with 1.21% difference. This is the 28th species of the S. asakoae species-group in Thailand, strengthening the evidence for high species diversity of this species-group.
A new species and a new record of the Simulium (Gomphostilbia) gombakense species-group (Diptera: Simuliidae) from Thailand

Takaoka H, Srisuka W, Low VL, Saeung A

Acta Trop, 2018 Sep;185:156-166.
PMID: 29772215 DOI: 10.1016/j.actatropica.2018.05.011

Larvae and adults reared from pupae of Simulium (Gomphostilbia) gombakense Takaoka & Davies from eight streams in five provinces of Thailand were genetically analyzed by using cytochrome c oxidase subunit 1 sequences. The material was composed of four lineages, of which lineages 2, 3 and 4 are genetically closely related to one another, but more distantly related to lineage 1, which is equivalent to typical S. (G.) gombakense from Peninsular Malaysia. Lineages 2, 3 and 4, which are morphologically indistinguishable, are designated as genoforms A, B and C within a species complex of S. (G.) paiense sp. nov., which is described based on specimens of lineage 2 (=genoform A). Simulium (G.) paiense sp. nov. is similar to S. (G.) gombakense from Peninsular Malaysia but appears to be barely distinguished by the relative length of the female fore basitarsus. Simulium (G.) thuathienense Takaoka & Sofian-Azirun is newly recorded from Thailand and its male is described for the first time. The female of S. (G.) gombakense is briefly described based on females reared from pupae collected from Peninsular Malaysia.

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links