1.No evidence for successful interspecific cross-mating of transgenic Aedes aegypti (L.) and wild type Aedes albopictus Skuse.
Lee HL ; Aramu M ; Nazni WA ; Selvi S ; Seshadri V
Tropical Biomedicine 2009;26(3):312-319
The natural and artificial mating of laboratory bred Aedes albopictus and transgenic Aedes aegypti RIDL-513A-Malaysian strain was conducted. The experiment consisted of crossmating of homologous Ae. aegypti RIDL female symbol X Ae. aegypti RIDL male symbol and reciprocal Ae. aegypti RIDL female symbol X Ae. albopictus WT male symbol. The other set comprised homologous Ae. albopictus WT female symbol X Ae. albopictus WT male symbol and reciprocal Ae. albopictus WT female symbol X Ae. aegypti RIDL male symbol. This study demonstrated that reproductive barriers exist between these two species. Cross insemination occurred between A. albopictus male and Ae. aegypti female and their reciprocals. There was 26.67% and 33.33% insemination rate in Ae. aegypti RIDL female cross-mating with A. albopictus WT male and Ae. albopictus female cross-mating with Ae. aegypti RIDL male, respectively. There was 0% hatchability in both directions of the reciprocals. There was also no embryonation of these eggs which were bleached. Although none of the female Ae. albopictus WT was inseminated in the cross-mating with Ae. albopictus WT female symbol X Ae. aegypti RIDL male symbol, a total of 573 eggs were obtained. The homologous mating was very productive resulting in both high insemination rate and hatchability rates. Generally there was a significantly higher insemination rate with artificial mating insemination of homologous than with artificial mating of reciprocal crosses. Interspecific mating between Ae. aegypti RIDL and Ae. albopictus wild type was not productive and no hybrid was obtained, indicating absence of horizontal transfer of introduced RIDL gene in Ae. aegypti to Ae. albopictus.
2.Dengue Vector Control in Malaysia- Challenges and Recent Advances
Lee HL ; Rohani A ; Khadri MS ; Nazni WA ; Rozilawati H ; Nurulhusna AH ; Nor Afizah AH ; Roziah A ; Rosilawati R ; Teh CH.
The International Medical Journal Malaysia 2015;14(1):11-16
Dengue is a serious mosquito borne disease common in tropical and sub-tropical countries including Malaysia.
There is at present a lack of specific treatment and an effective tetravalent vaccine against dengue. The control
of dengue depends solely on the suppression of the two most important vectors namely, Aedes aegypti and Ae
albopictus. Despite intensive and extensive control efforts by health agencies, the disease continues to spread.
This paper updates various innovations on control of dengue vectors. Gene-based sterile insect technique
using the RIDL technology for both Aedes aegypti & Ae albopictus control has now been actively researched and
field trials are pursued to evaluate the effectiveness of the technology. The release of Wolbachia-infected Ae
aegypti is another dengue control innovation. The infected mosquito cannot support development of dengue
virus and has shorter life span. Other innovations include: auto-dissemination of insect control agents using
ovitrap, autocidal adult and larva trap, outdoor residual spraying, insecticidal paint and biocontrol agent. In
other innovation, outbreak prediction capability is enhanced by developing model based on environmental data
and analysis utilising neural network.
3.Predation on pupa of Chrysomya rufifacies (Marquart) (Diptera: Calliphoridae) by parasitoid, Exoristobia philippinensis Ashmead (Hymenoptera: Encyrtidae) and Ophyra spinigera larva (Diptera: Muscidae).
Heo CC ; Nazni WA ; Lee HL ; Jeffery J ; Baharudin O ; Chen CD ; Lau KW ; Sofian Azirun M
Tropical Biomedicine 2009;26(3):369-372
A forensic entomological study was conducted using monkey carcasses (Macaca fascicularis Raffles) that were placed in either an outdoor or indoor environment at a coastal area in Tanjung Sepat, Selangor, Malaysia during May until August 2008. We collected pupae of Chrysomya rufifacies (Marquart) from the carcasses and kept them individually. The emergence of 13 parasitic microhymenopteran, from one of the pupae occurring within a week were identified as Exoristobia philippinensis Ashmead (Hymenoptera: Encyrtidae). Another observation was made whereby a pupa of C. rufifacies was predated by a muscid larva, Ophyra spinigera (Stein). The larva squeezed into the pupa and consumed the contents. This paper report C. rufifacies as a new host record for E. philippinensis in Malaysia and highlighted the predatory behavior of O. spinigera larva in natural environment.
4.Nosocomial nasal myiasis in an intensive care unit
NAZNI WA ; JEFFERY J ; LEE HL ; LAILATUL AKMAR MN ; CHEW WK ; HEO CC ; SADIYAH I ; KHAIRUL ASUAD M ; HEAH SK ; MOHD HISHAM H
The Malaysian Journal of Pathology 2011;33(1):53-56
A 73-year-old Chinese man was admitted to the Accident and Emergency Premorbid Ward of a
local hospital in Malaysia. The patient complained of shortness of breath with cough and was in a
semi-conscious state. He was later admitted to an intensive care unit (ICU) of the hospital. Six days
after admission 5-6 maggots were recoverd from the nasal cavity. The maggots were identifi ed as the
third-instar larvae of Lucilia cuprina Wiedmann (Diptera: Calliphoridae) based on the morphological
characteristics. This patient was classifi ed as having nosocomial myiasis. The presence of the third
instar larvae indicated that the infestation was not more than three to four days. An adult sarcophagid
identifi ed as Parasarcophaga rufi cornis (Fabricius) caught in the ICU where the patient was warded
provided further evidence of the potential for the nosocomial infestation.