Wu-Chun Tu

Prof. Dr. Wu-Chun Tu


Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 December 2019 in Parasites & Vectors
Verified
Journal Article
Open access
PDF file
HSHadian Iman Sasmita
Hadian Iman Sasmita
WTWu-Chun Tu
Wu-Chun Tu
LBLee-Jin Bong
Lee-Jin Bong
KNKok-Boon Neoh
Kok-Boon Neoh
Background: Producing high quality sterile males is vital in Aedes aegypti rear-and-release birth control strategies. Larval diets, rearing temperatures, and their interactions determine the accumulation rates of essential nutrients in larvae, but these factors have been understudied in relation to mass-rearing techniques for producing eminent males. Methods: We compared the effects of two larval diets, a cereal-legume-based diet (Khan’s diet) and a standard larval diet developed in the FAO/IAEA Insect Pest Control Laboratory (IAEA 2 diet). Diets were tested at selected temperatures for both larval and male adult life history traits, adult extreme temperature tolerance, and mating capacity relative to energy reserves of reared male adult Ae. aegypti. Results: Khan’s diet resulted in shorter immature development time at each test temperature (except for 25 °C) than an IAEA 2 diet. Larvae reared at 28 °C and 32 °C with Khan’s diet demonstrated low pupation rates (c.80%). We accounted for these phenomena as secondary sex ratio manipulation, because a higher proportion of male adults emerged at 28 °C and 32 °C than that for the IAEA 2 diet. In general, the pupal development time shortened as temperature increased, resulting in higher teneral energy reserves in male mosquitoes. High energy reserves allowed male mosquitoes reared with Khan’s diet to have higher adult longevity (5–6 days longer when sugar-fed and 2–3 days longer when water-fed) and tolerance of heat stress than those fed on the IAEA 2 diet. The IAEA 2 diet produced larger male mosquitoes than Khan’s diet did: mosquitoes fed on Khan’s diet were 1.03–1.05 times smaller than those fed on the IAEA 2 diet at 28 °C and 32 °C. No evidence indicated reduced mating capacity for small mosquitoes fed on Khan’s diet. Conclusions: Larvae reared at 28 °C and 32 °C with Khan’s diet were characterized by shorter immature development time compared with those fed on the IAEA 2 diet. Adult mosquitoes produced from that larval rearing condition exhibited a significant male bias, long lifespan, and better endurance against extreme temperatures relative to energy reserves. Thus, the larval diet at rearing temperature of 28 °C and 32 °C optimized rearing techniques for the sterile insect programmes. However, mating competitiveness and flight performance of adult males require further investigation.

28 October 2021 in PLOS Neglected Tropical Diseases
Verified
Journal Article
Open access
PDF file
HSHadian Iman Sasmita
Hadian Iman Sasmita
KNKok-Boon Neoh
Kok-Boon Neoh
SYSri Yusmalinar
Sri Yusmalinar
TATjandra Anggraeni
Tjandra Anggraeni
NCNiann-Tai Chang
Niann-Tai Chang
WTWu-Chun Tu
Wu-Chun Tu
Larval surveillance is the central approach for monitoring dengue vector populations in Indonesia. However, traditional larval indices are ineffective for measuring mosquito population dynamics and predicting the dengue transmission risk. We conducted a 14-month ovitrap surveillance. Eggs and immature mosquitoes were collected on a weekly basis from an urban village of Bandung, namely Sekejati. Ovitrap-related indices, namely positive house index (PHI), ovitrap index (OI), and ovitrap density index (ODI), were generated and correlated with environmental variables, housing type (terraced or high-density housing), ovitrap placement location (indoor or outdoor; household or public place), and local dengue cases. Our results demonstrated that Aedes aegypti was significantly predominant compared with Aedes albopictus at each housing type and ovitrap placement location. Ovitrap placement locations and rainfall were the major factors contributing to variations in PHI, OI, and ODI, whereas the influences of housing type and temperature were subtle. Indoor site values were significantly positively correlated to outdoor sites’ values for both OI and ODI. OI and ODI values from households were best predicted with those from public places at 1- and 0-week lags, respectively. Weekly rainfall values at 4- and 3-week lags were the best predictors of OI and ODI for households and public places, respectively. Monthly mean PHI, OI, and ODI were significantly associated with local dengue cases. In conclusion, ovitrap may be an effective tool for monitoring the population dynamics of Aedes mosquitoes, predicting dengue outbreaks, and serving as an early indicator to initiate environmental clean-up. Ovitrap surveillance is easy for surveyors if they are tasked with a certain number of ovitraps at a designated area, unlike the existing larval surveillance methodology, which entails identifying potential breeding sites largely at the surveyors’ discretion. Ovitrap surveillance may reduce the influence of individual effort in larval surveillance that likely causes inconsistency in results.

1 August 2019 in Insect Biochemistry and Molecular Biology
Verified
Journal Article
Closed access
CSChalida Sri-In
Chalida Sri-In
SWShih-Che Weng
Shih-Che Weng
WCWen-Yu Chen
Wen-Yu Chen
BWBetty A. Wu-Hsieh
Betty A. Wu-Hsieh
WTWu-Chun Tu
Wu-Chun Tu
SSShin-Hong Shiao
Shin-Hong Shiao

29 May 2020 in PLOS ONE
Verified
Journal Article
Open access
PDF file
CSChalida Sri-In
Chalida Sri-In
SWShih-Che Weng
Shih-Che Weng
SSShin-Hong Shiao
Shin-Hong Shiao
WTWu-Chun Tu
Wu-Chun Tu
A simple device using folded Parafilm-M as an artificial blood feeder was designed for studying two important dengue vector mosquitoes, Aedes aegypti and Aedes albopictus. The efficiency of the artificial blood feeder was investigated by comparing the numbers of engorged mosquitoes that fed on the artificial blood feeder versus mice as a live blood source. Significantly more engorged females Aedes aegypti fed on the artificial blood feeder than on mice. In addition, the artificial feeder could serve as a useful apparatus for oral infection via artificial blood meals, and for saliva collection in mosquitoes. Our method enabled us to collect saliva from multiple mosquitoes at once, providing sufficient infected saliva for determination of the virus titer by plaque assay analysis. Our artificial feeder has the advantage that it is simple, inexpensive, and efficient.

1 April 2007 in Journal of Clinical Gastroenterology
Verified
Journal Article
Closed access
WTWu-Chun Tu
Wu-Chun Tu
HCHsin-Cheng Chen
Hsin-Cheng Chen
KCKe-min Chen
Ke-min Chen
LTLi-Cheng Tang
Li-Cheng Tang
SLShih-Chan Lai
Shih-Chan Lai
Here we reported the first case in Taiwan of human intestinal myiasis caused by larvae of Telmatoscopus albipunctatus. The 21-year-old male patient experienced gastroenteritis and anal itching. During the patient's first hospital visit the doctor suspected Enterobius infection. After treatment with anthelmintic mebendazole, 5 live larvae were passed out in the feces. Symptoms were resolved a few days later. The larvae were brown and slender, measuring approximately 10 mm in length. The worms were located in the intestine. Subsequent examination showed that the cause was an infestation of larvae of T. albipunctatus. The patient was likely infected by ingestion of eggs or early-stage larvae in contaminated food.

26 November 2020 in Insects
Verified
Journal Article
Open access
PDF file
WLWei-Ting Liu
Wei-Ting Liu
TCTien-Lai Chen
Tien-Lai Chen
RHRoger F. Hou
Roger F. Hou
CCCheng-Chen Chen
Cheng-Chen Chen
WTWu-Chun Tu
Wu-Chun Tu
The Asian tiger mosquito, Aedes albopictus, is of crucial concern to the public and veterinary health because of its vector role in transmission of several mosquito-borne diseases. Over the past decades, entomopathogenic nematodes (EPNs) have been used to control important agricultural insect pests and are considered to be effective against mosquitoes as well. The objectives of this study were to investigate the mosquitocidal effects of Steinernema abbasi to Ae. albopictus and the encapsulation processes of invading nematodes in the mosquito host. In this study, we found that S. abbasi was pathogenic to 3rd and 4th instar larvae of Ae. albopictus by entering the hemocoel of the 3rd and 4th instar larvae mainly through mouth and gastric caecum or by penetrating pupae through the intersegmental membrane or trumpet. The mosquito larvae infected with a single nematode caused a high mortality. Although EPNs in the hemocoel of mosquitoes were melanized and encapsulated, most Ae. albopictus larvae failed to survive after infection with S. abbasi. Overall, we demonstrated that S. abbasi is pathogenic to Ae. albopictus larvae, suggesting that this S. abbasi isolate has potential as a biocontrol agent for managing this vector mosquito.