The aim of this study is to investigate the feasibility and outcomes of using Gravid Oviposition Sticky (GOS) trap and dengue NS1 antigen tests for indoor and outdoor dengue/Aedes surveillance in the field. A one-year community-based study was carried out at Sungai Buloh Hospital Quarters, Selangor, Malaysia. GOS traps were first placed outdoors in three apartment blocks (Anggerik, Bunga Raya and Mawar). Beginning 29th week of the study, indoor traps were set in two apartment units on every floor in Anggerik. All female Aedes mosquitoes caught were tested for the presence of dengue NS1 antigen. Dengue seroprevalence and knowledge, attitude and practices on dengue prevention of the community and their reception to the surveillance approach were also assessed. Dengue-positive mosquitoes were detected at least 1 week before a dengue onset. More mosquitoes were caught indoors than outdoors in block Anggerik, but the total number of mosquitoes caught in all 3 blocks were similar. There was a significant difference in distribution of Ae. aegypti and Ae. albopictus between the 3 blocks. 66.1% and 3.4% of the community were positive for dengue IgG and IgM, respectively. Most respondents think that this surveillance method is Good (89%) and support its use nationwide. Dengue case ratio in the study apartment blocks decreased from year 2018 to 2019. This study demonstrated the practicality of performing proactive dengue/Aedes surveillance inside apartment units using the GOS traps. This surveillance method can be performed with immediate result output in the field.
In a coastal village in northwest Malaysia, 3231 fed Anopheles females of eight to 10 species were collected, marked with fluorescent dust, and released on three consecutive nights. In collections made on the 10 nights after the first release, 58 mosquitoes of three species, An. lesteri paraliae, An. subpictus and An. vagus, were recaptured; the recapture rates were 3.42%, 1.19% and 0.97%, respectively. The data for An. subpictus and An. vagus were insufficient for further analysis. Those for An. l. paraliae were plotted against time of recapture and, from the regression coefficient, an estimate of 0.68 was obtained for the daily survival rate. An independent estimate based on the parous rate during the previous year was 0.55. The temporal distribution of the recaptures strongly suggested a gonotrophic cycle and oviposition cycle of two days.
Megaselia scalaris (Loew) (Diptera: Phoridae) provides great evidential value in estimating the postmortem interval (PMI) compared with other dipterans due to its common occurrence on human corpses both indoors and in concealed environments. Studies have focused on the effect of temperature, larval diet, and photoperiod on the development of the species; however, knowledge of M. scalaris development at different moisture levels is insufficient. This study aimed to investigate the effects of substrate moisture on the larval development time, pupal recovery, pupal weight, adult emergence, and adult head width of M. scalaris. The larvae were reared in five replicates on substrates with six moisture levels ranging from 50 to 90%. Larvae and puparia were sampled daily, and the collection time, number, and weight were recorded, measured, and then compared using multivariate analysis of variance with a post hoc least significant difference test. Larvae developed most quickly (3.75 ± 0.04 d) at 50% substrate moisture; the larvae were able to survive in extremely wet substrates (90% moisture), but the development time was significantly longer (6.48 ± 0.19 d). Moisture greatly influenced the pupation rate and adult emergence but showed a weak effect on the pupae weight and adult head width. Due to the significance of moisture on the development of M. scalaris, PMI estimation using M. scalaris with cadavers of different moisture content must be carefully conducted to avoid inaccuracy.
We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.
Scuttle flies of genus Puliciphora Dahl (Diptera: Phoridae) are recorded for the first time in Malaysia from rabbit carcasses placed in concealed environments. They consist of Puliciphora borinquenensis Wheeler ♂♀, Puliciphora obtecta Meijere ♀ and Puliciphora beckeri Meijere ♀. All species were obtained from rabbit carcasses in used luggage and garbage bin placed at Forensic Science Simulation Site, Universiti Kebangsaan Malaysia, Bangi, Selangor. The specimens were collected from the carcasses using a modified Malaise trap, an entomological aspirator and preserved in 70% ethanol. This report expands the geographical distributions of these species and their microhabitat, suggests its possible important role in forensic entomology.
In Penang, Malaysia, the Oriental and Afrotropical Megaselia curtineura (Brues) and the Oriental and Japanese Megaselia spiracularis Schmitz are reported from human corpses, these being the first reports of these species in such forensic cases.
Considering that crimes against animals such as illegal killing and cruelty have been alarmingly increasing and since burning is one of the common ways for disposing cadavers, ability to estimate minimum postmortem interval (PMI) using entomological data merits consideration. Chrysomya megacephala and Chrysomya rufifacies are common necrophagous species recovered from cadavers in many countries including Malaysia. Specific studies focusing on the oviposition and developmental patterns of both species on cadavers manifesting different levels of burn as described by the Crow-Glassman Scale (CGS) remain scarce. In four replicates, rabbit carcasses were burned to CGS levels #1, #2 and #3 by varying the amount of petrol used and duration of burning. Oviposition by C. megacephala and C. rufifacies was delayed by one day in the case of carcasses burned to the CGS level #3 (p<0.05) when compared with that of controls. Such delay in oviposition was not observed in the CGS level #1 and #2 carcasses. No significant differences (p>0.05) in the duration of development were found between control and burned carcasses. These findings deserve consideration while estimating minimum PMI since burning as a mean for disposing animal and human cadavers is gaining popularity.
Dengue is a disease propagated by vectors namely Aedes spp. mosquitoes. One of the effective approaches to control dengue is through integrated vector management and intervention programs. COMBI or Communication for Behavioral Impact is a strategic approach to control the Aedes population as well as dengue cases. This study was conducted at Taman Desa Kolej, Nilai, Negeri Sembilan, an suburban residential area to determine the effectiveness of COMBI, by using questionnaire and entomological survey as well as implementation of an intervention program. We carried out activities such as the establishment of COMBI promoter team, clean up events, talk shows with the residential community and distributed pamphlets containing information about dengue. Results indicated significant difference (p
Introduction: Entomological surveillance is crucial to determine the abundance of dengue vector and to evaluate breeding areas of Aedes aegypti and Aedes albopictus. The objective of this study is to determine the distribution and breeding preference for both Ae. aegypti and Ae. albopictus in dengue endemic areas. Materials and Methods: Ovitraps surveillance was conducted in two dengue endemic areas; AU2, Keramat and Seksyen 7, Shah Alam, Selangor. A minimum number of 100 ovitraps were deployed for 5 days in the study sites. Samples collected were brought back to the lab and all larvae recovered were identified to species level. Results: The ovitap index (OI) in both localities exceeded the transmission threshold of 10% with the OI recorded ranged from 42.3-79.8% in AU2, Keramat and 16.7-42.9% in Seksyen 7, Shah Alam. Ae. albopictus was the dominant species in AU2 Keramat with the highest ratio Ae. aegypti to Ae. albopictus recorded was 1.00:22.79. Nonetheless, in Seksyen 7, Shah Alam the difference in Ae. aegypti to Ae. albopictus ratio is not really prominent with 1.00:3.61 for ovitraps deployed outdoor and 3.40:1.00 for ovitraps set indoor. It was determined that single infestation of either Ae. aegypti or Ae. albopictus is more frequent for ovitraps deployed indoor and/or outdoor, respectively. It was also determined that mixed infestations were found in this study indicating that both species can oviposit in the same container. Conclusion: This study indicates that OI is still above transmission threshold in both study sites. While Ae. aegypti and Ae. albopictus remain as a dominant indoor and outdoor breeder, respectively, mixed breeding of Aedes species in a same container was also observed.
Forensic entomological specimens collected from human decedents during crime scene investigations in Malaysia in the past 6 years (2005-2010) are reviewed. A total of 80 cases were recorded and 93 specimens were collected. From these specimens, 10 species of cyclorrphagic flies were identified, consisting of Chrysomya rufifacies (Macquart) -38 specimens (40.86%), Chrysomya megacephala (Fabricius) -36 specimens (38.70%), Chrysomya villeneuvi (Patton) -2 specimens (2.15%), Chrysomya nigripes (Aubertin) -2 specimens (2.15%), Chrysomya pinguis (Walker) -1 specimen (1.08%), Hermetia illucens (Linnaeus) -1 specimen (1.08%), Hemipyrellia liguriens (Wiedemann) -5 specimens (5.37%), Synthesiomyia nudiseta (Wulp) -1 specimen (1.08%), Megaselia scalaris (Loew)-1 specimen (1.08%) and Sarcophaga ruficornis (Fabricius) -4 specimens (4.30%). In two specimens (2.15%), the maggots were not identifiable. Ch. megacephala and Ch. rufifacies were the commonest species found in human decedents from three different ecological habitats. S. nudiseta is an uncommon species found only on human cadavers from indoors. A total of 75 cases (93.75%) had a single fly infestation and 5 cases (6.25%) had double fly infestation. In conclusion, although large numbers of fly species were found on human decedents, the predominant species are still those of Chrysomya.
Forensic entomology refers to the science of collection and analysis of insect evidence in order to determine the minimum time period since death. This study aimed to investigate the occurrence of forensically important flies on 34 human remains referred to Universiti Kebangsaan Malaysia Medical Centre over a period of three years. Entomological specimens were collected at the death scenes and/or during autopsies. Live specimens were reared into adults while preserved specimens were processed for species identification. Five families, seven genera and nine species of flies were identified from human remains. The results of the study showed Chrysomya megacephala (Calliphoridae) maggots occurred on corpses with the highest frequency (70.6%), followed by Ch. rufifacies (Calliphoridae) (44.1%), sarcophagid fly (Sarcophagidae) (38.2%), Synthesiomya nudiseta (Muscidae) (20.6%), Megaselia scalaris (Phoridae) (14.7%), Lucilia cuprina (Calliphoridae) (5.9%), Ch. nigripes (Calliphoridae) (5.9%), Eristalis spp. (Syrphidae) (5.9%) and Hydrotaea spinigera (Muscidae) (2.9%). The greatest fly diversity occurred on remains recovered indoors (eight species) compared to outdoors (three species). Whilst, single and double infestations were common for both indoor and outdoor cases, multiple infestation of up to six species was observed in one of the indoor cases. Although large numbers of fly species were found on human remains, the predominant species were still those of Chrysomya, while S. nudiseta was found only on human remains recovered from indoors. The present study provides additional knowledge in the context of Malaysian forensic entomology and the distribution of forensically important flies which is of relevance to forensic science.
In estimating the postmortem interval (PMI) using maggots obtained during autopsy, the forensic entomologist makes decisions regarding the effects of low-temperature storage of the body on the insects. In this case report, a corpse was found in an abandoned house in the residential area of Bukit Mertajam, Penang, Malaysia. The maggots were found to be alive inside the mouth of the deceased although the corpse had been in the morgue cooler for 12 days. The maggots were reared and identified as Chrysomya megacephala (Fabricius). The emerged adult flies were kept as a stock colony, and the duration of development under the indoor fluctuating temperature regime was studied. The total duration of developmental process of this species was 9.5 ± 0.5 days, and the PMI estimated was 3.2 ± 0.6 days. This case report demonstrates the survival of Ch. megacephala maggots for 12 days and their growth inside the morgue cooler.
The likelihood of dipteran maggots colonizing a corpse due to nocturnal oviposition can be used to challenge the postmortem interval (PMI) estimated assuming diurnal oviposition. Earlier experiments tested nocturnal oviposition behavior by exposing fresh baits once during a single night. In this pilot study, oviposition behavior was studied using beef baits, which, simulating the decay of the body seen in case situations, decomposed inside cages designed to open and close at scheduled intervals during consecutive night or twilight periods. Freshly hatched maggots from diurnally oviposited eggs emerged in control baits on the third day, while a limited number of maggots attributable to nocturnal or twilight oviposition were observed in experimental baits only on the fifth or sixth day, indicating a categorical delay. These results suggest that such delayed and limited nocturnal oviposition is not forensically significant since the larger maggots deriving from diurnal oviposition would be the ones considered when estimating PMI.
There is accumulating evidence that criminals wrap dead bodies in an attempt to conceal evidence. To anticipate the forensic implications of this phenomenon, we examined whether flies that are naturally associated with cadavers exhibit a delay in attendance or differ in species composition and abundance patterns because of the presence of wrapping material. Wrapped and exposed carcasses of dead monkeys placed in an oil plantation in Kedah, Malaysia, were visited over 50 d. On daily visits to each of the six carcasses, visiting adult flies were sampled using hand nets. Flies of 12 families were encountered. Calliphoridae (Chrysomya rufifacies Macquart and C. megacephala (F.) was the most prevalent family, followed by Sphaeroceridae. Some families tended to be more abundant in WRCs (i.e., Calliphoridae, Muscidae, and Phoridae), whereas others (i.e., Piophilidae, Sepsidae, and Psychodidae) were more prevalent in exposed carcasses. Wrapping delayed the arrival of all fly species encountered, with delays varying from 1 to 13 d depending on species. Wrapping did not affect species composition of flies, but prolong the occurrence of some species. The results of the current study emphasize the need to take into consideration the presence of a wrap when estimating postmortem interval.
Flies attracted to human remains during death investigations were surveyed in north Peninsular Malaysia. Six families, eight genera, and 16 species were identified from human remains, with the greatest fly diversity occurring on remains recovered indoors. The total relative frequency of species was led by Chrysomya megacephala (Fabricius, 1794) (46%), followed by Chrysomya rufifacies (Macquart, 1842) (22%), Sarcophaga (Liopygia) ruficornis (Fabricius, 1974) (5%), Sarcophaga spp. (4%), Synthesiomyia nudiseta Wulp, 1883 (6%), Megaselia spp. (3%), Megaselia scalaris (Loew, 1866), (2%), Megaselia spiracularis Schmitz, 1938 (2%), and Chrysomya villeneuvi Patton, 1922 (2%). Hemipyrellia tagaliana (Bigot, 1877), Desmometopa sp., Megaselia curtineura (Brues, 1909), Hemipyrellia ligurriens Wiedemann 1830, Ophyra sp., Sarcophaga princeps Wiedemann 1830, Piophila casei (Linnaeus, 1758), and unidentified pupae each represented 1%, respectively.
In forensic entomology practice, it is more common to use raw animal tissue to breed dipteran larvae and it often brings unpleasant odour in the laboratory. Few studies suggested the use of synthetic diets, mainly agar-based media, as alternatives to animal tissue but it is rarely being practiced in forensic entomology laboratory. The present study observed the growth of a forensically important fly, Megaselia scalaris (Loew) on raw cow’s liver, nutrient agar, casein agar and cow’s liver agar. A total of 100 M. scalaris eggs were transferred each into the different media and placed in an incubator at 30°C in a continuous dark condition. Data on length and developmental period were collected by randomly sampling three of the largest larvae from each rearing media, twice a day at 0900 and 1500 hours until pupariation. M. scalaris larvae reared on raw cow’s liver recorded the highest mean length (4.23 ± 1.96 mm) followed by cow’s liver agar (3.79 ± 1.62 mm), casein agar (3.14 ± 1.16 mm) and nutrient agar (3.09 ± 1.11 mm). Larval length in raw liver and liver agar were significantly different from those in nutrient and casein agar (p < 0.05). Larvae bred in liver agar and raw liver recorded the shortest larval duration before entering the post-feeding stage (89 hours), followed by nutrient agar (119 hours) and casein agar (184 hours). Total developmental time from oviposition until adult emergence for M. scalaris in liver agar and raw liver was approximately 163 hours. All puparia in nutrient agar and casein agar failed to hatch. This research highlighted the potential use of cow’s liver agar as an alternative diet of raw liver to culture M. scalaris in laboratory.
Phorid flies play an important role in forensic cases and can cause myiasis in humans. Studies on phorid flies species diversity are still limited in Malaysia. This research was carried out to collect information about species and frequency distribution of phorid flies as to provide more information on their roles in forensic and medical entomology. Bait trap was used with 100 g beef liver as baits. The species of the flies were identified using identification keys from Disney as well as Brown and Oliver. There were 449 phorid flies found in Kepong, Kuala Lumpur including Megaselia scalaris, Megaselia spiracularis, Megaselia sp. and phorid flies of genus X. Female phorid flies (98.89%) were found more prone to be trapped compared to male phorid flies (1.11%). Most phorid flies trapped in Kepong, Kuala Lumpur were from genus Megaselia and consisted of female flies. A total of five species of phorid flies probably new to science were also discovered. This study showed that Megaselia flies were found indoors rather than in open spaces. This was corresponding to their discoveries among the decomposing corpse found inside premises.
An entomological study was conducted in Tanjung Sepat, Selangor, Malaysia in May until September 2007 revealing five species of butterflies (all from family Nymphalidae) were attracted to pig carcasses placed in an oil palm plantation. Euploea mulciber (Cramer 1777), Hypolimnas bolina (Linnaeus 1758), Elymnias hypermnestra (Linnaeus 1763), Mycalesis mineus (Linnaeus 1758) and Ypthima baldus (Fabricius 1775) came to the carcasses at different stages of decomposition. From this study, we know that nymphalid butterflies are attracted to carcasses but their roles are most probably unimportant in post-mortem estimation.
Establishing time of death has been extensively studied for the last 30 years. Parameters that have been studied included body temperature, biochemistry of rigor mortis, putrefactive changes and entomology. Despite an extensive study in these parameters it was found that all of the parameters were very much dependent on external factors like changes in surrounding temperature and activities done prior to death. To solve this problem, we decided to monitor the mechanism that occurs during death. Until now, various researches have found that during the early stage of death, heart and perfusion to the cells will stop. This will cause the cells to start the death process. The death of the cell will occurs either through apoptosis or necrosis. During apoptosis the cells will switch on and off a few proteins in a sequence. Based on this understanding, a study was conducted to determine if area ratio of apoptosis: necrosis and apoptotic p53 and Bcl-2 markers can be used as a reliable postmortem interval marker (PMI). Sampling of the study had involved 100 dead human skins with a known PMI. All samples were obtained from forensic unit of Hospital Kuala Lumpur (UFHKL). Ratio of apoptosis: necrosis areas were determined using hematoxilin and eosin staining while apoptosis p53 and Bcl-2 markers were done using an apoptosis kit. All staining were then indexed and plotted against PMI data obtained from UFHKL. Results indicated that there were no significant correlations between ratio of apoptosis: necrosis area against PMI (p = 0.144). Whereas for both apoptotic markers p53 and Bcl-2 PMI had shown a significant correlation (p < 0.000 for both results). In conclusion, we suggest that p53 and Bcl-2 parameters should be studied further since it is very likely that it could be a good indicator for PMI.