First record of Diamesus osculans (Vigors, 1825) (Coleoptera: Silphidae) colonization on a human corpse.

A partially skeletonized human corpse was found in bushes in Selangor, Malaysia in June 2020. Entomological evidence was collected during the autopsy and sent to the Department of Medical Microbiology and Parasitology, Faculty of Medicine, Universiti Teknologi MARA (UiTM) for minimum postmortem interval (PMImin) analysis. Standard protocols were applied when processing preserved and live insect specimens of both larval and pupal stages. Entomological evidence revealed that the corpse was colonized by Chrysomya nigripes Aubertin, 1932 (Diptera: Calliphoridae) and Diamesus osculans (Vigors, 1825) (Coleoptera: Silphidae). Chrysomya nigripes was chosen as the PMImin indicator as this fly species is an earlier colonizer compared to D. osculans beetle larvae which their presence is the indicative of late stage of decomposition. For the present case, the pupae of C. nigripes were the oldest insect evidence collected and based on the available developmental data, the estimated minimum PMI was established between 9 and 12 days. It is noteworthy to highlight that this is the first record of D. osculans colonization on a human corpse.

Machine learning analysis of wing venation patterns accurately identifies Sarcophagidae, Calliphoridae and Muscidae fly species.

In medical, veterinary and forensic entomology, the ease and affordability of image data acquisition have resulted in whole-image analysis becoming an invaluable approach for species identification. Krawtchouk moment invariants are a classical mathematical transformation that can extract local features from an image, thus allowing subtle species-specific biological variations to be accentuated for subsequent analyses. We extracted Krawtchouk moment invariant features from binarised wing images of 759 male fly specimens from the Calliphoridae, Sarcophagidae and Muscidae families (13 species and a species variant). Subsequently, we trained the Generalized, Unbiased, Interaction Detection and Estimation random forests classifier using linear discriminants derived from these features and inferred the species identity of specimens from the test samples. Fivefold cross-validation results show a 98.56 ± 0.38% (standard error) mean identification accuracy at the family level and a 91.04 ± 1.33% mean identification accuracy at the species level. The mean F1-score of 0.89 ± 0.02 reflects good balance of precision and recall properties of the model. The present study consolidates findings from previous small pilot studies of the usefulness of wing venation patterns for inferring species identities. Thus, the stage is set for the development of a mature data analytic ecosystem for routine computer image-based identification of fly species that are of medical, veterinary and forensic importance.

Morphological abnormalities and multiple mitochondrial clades of Rhipicephalus haemaphysaloides (Ixodida: Ixodidae).

Rhipicephalus haemaphysaloides is endemic in South and Southeast Asia, and it is known to parasitise domestic animals such as cattle, horses, sheep, and dogs. Despite infestation on multiple hosts, little attention has been paid to its morphological and molecular variation. The present study describes local morphological abnormalities for the first time in R. haemaphysaloides from Malaysia, and highlights the presence of three cytochrome c oxidase subunit I (COI) operational taxonomic units with 0.46-9.81% distances within the so-called R. haemaphysaloides in Malaysia, Thailand, and Pakistan.

The Importance of Habitat in the Ecology of Decomposition on Rabbit Carcasses in Malaysia: Implications in Forensic Entomology.

The stages of decomposition and the faunal succession on rabbit carcasses in three different habitats, namely jungle, rural, and highland areas, were studied. Three New Zealand White rabbit (Oryctolagus cuniculus) carcasses weighing ∼2 kg were sampled daily until the decomposition process was completed. Representative specimens of adult flies, larvae, pupa, and mites were collected from the carcasses and processed in the laboratory. There were differences in decomposition rate and faunal succession between the carcasses. The fastest rate of decomposition was recorded in rural area, and the slowest rate of decomposition was recorded in highland area. The carcasses exhibited the same pattern of colonization by adult flies, but the dominant species of larvae and adult flies on each carcass in specific habitats were different. The primary species of flies recorded in jungle were Chrysomya megacephala F., Chrysomya rufifacies (Macquart), Chrysomya chani Kurahashi, Chrysomya villenuevi Patton, Chrysomya nigripes Aubertin, Chrysomya pinguis (Walker), Hemipyrellia ligurriens (Wiedemann), Hemipyrellia tagaliana (Bigot), Hypopyiopsis fumipennis (Walker), Hypopygiopsis violacea (Macquart), and Hydrotaea spinigera Stein represented by both adults and larvae. Musca domestica L., Atherigona sp., Lioproctia pattoni (Senior-White), Lioproctia saprianovae Pape & Bänziger, and Seniorwhitea princeps (Wiedemann) were represented by adults only. The biodiversity of flies in the rural area were C. megacephala, C. rufifacies, H. ligurriens, Fannia canicularis L., Hydrotaea chalcogaster (Wiedemann), and Hyd. spinigera represented by both adults and larvae, meanwhile M. domestica, Atherigona sp., Boettcherisca peregrina (Robineau-Desvoidy), Parasarcophaga taenionota Wiedemann, Parasarcophaga scopariiformis Senior-White, and S. princeps were represented by adults only. The species of flies collected in the highland area were Lucilia porphyrina (Walker), C. megacephala, C. rufifacies, C. villenuevi, C. pinguis, H. ligurriens, Hyd. spinigera, Hyd. chalcogaster, F. canicularis, and Boettcherisca highlandica Kurahashi & Tan represented by both adults and larvae, whereas C. nigripes, Chrysomya thanomthini Kurahashi & Tumrasvin, M. domestica, Atherigona sp., Parasarcophaga albiceps Meigen, P. taenionota, Sepsidae, Phoridae, and Millichidae were represented by adults only. Faunal succession followed the sequence of dominant flies, i.e., Calliphoridae, Sarcophagidae, Muscidae, Sepsidae, and lastly Stratiomyidae for jungle, or Sepsidae for rural and highland studies. Mites, from suborders Mesostigmata, Prostigmata, Astigmatina, and Oribatida, were also recovered throughout decomposition, which could be used for future implementation in forensic investigations. The data obtained from this study could provide more accurate indicators for local forensic scientists in solving criminal cases especially on the determination of time and primary location of death.

Detection of sarcocystosis in goats in Malaysia by light microscopy, histology, and PCR.

A number of methods have been used for the detection of the presence of microsarcocysts in animals, but little information exists on the value between the various methods. This study therefore examined for Sarcocystis spp. using three different methods in 105 samples of skeletal muscle collected from goats slaughtered in an abattoir in Selangor, Malaysia from January to February 2014. Three methods were used, direct light microscopy of squashed fresh muscle tissues; histological examination of fixed, sectioned, and hematoxylin and eosin (H&E)-stained samples of muscle; and molecular identification by polymerase chain reaction (PCR). Of the 105 tissue samples, 55 (52.38 %) were positive by light microscopy (LM), 46 (43.8 %) by histology, and 95 (90.48 %) by PCR. Only 29 (27.6 %) and 5 (4.76 %) samples were positive and negative, respectively, by all three methods. The cysts were elongated to a spindle shape with a mean size of 393.30 × 81.6 µm and containing banana-shaped bradyzoites of size 12.32 × 2.08 µm. The wall of the cyst was radially striated with a thickness of 2.83 µm. Samples were tested for the presence of Sarcocystis-specific 18S rRNA and were identified as Sarcocystis capracanis. Of the three methods used, the PCR test appears to be the most useful method for the diagnosis of sarcocystosis especially for species identification.

Haemaphysalis wellingtoni (Acari: Ixodidae) from the helmeted guineafowl, Numida meleagris (Galliformes: Numididae): A new tick-host record in Peninsular Malaysia.

This paper describes a new tick-host record of Haemaphysalis wellingtoni from the helmeted guineafowl (Numida meleagris) in Peninsular Malaysia. This record is also the first report of a tick infestation from N. meleagris in Asia. A checklist of the tick-guineafowl associations has been designed, resulting in 32 tick species including H. wellingtoni recorded as infesting N. meleagris worldwide. A list of pathogens harboured or transmitted by H. wellingtoni is provided. The status of H. wellingtoni as a true parasite of N. meleagris, and the health threat posed to the guineafowls are discussed in this paper.

Tick-associated Trypanosoma species (Apicomplexa: Kinetoplastida) from cattle ticks (Acari: Ixodidae) in Peninsular Malaysia.

A Trypanosoma screening was conducted on 130 pools comprising 1,241 ticks, collected from 674 selected farm ruminants in Peninsular Malaysia. Of these, nine pools were tested positive for Trypanosoma. Subsequent BLAST searches revealed that the 18S rRNA gene sequences were closely related to Trypanosoma rhipicephalis isolate Chaco CB, with percentage similarities ranging from 95.56 % to 99.84 %. Phylogenetic analysis showed that three of the nine sequences formed a clade with Trypanosoma rhipicephalis. The remaining six Trypanosoma sequences formed a distinct clade, separate from T. rhipicephalis and other Trypanosoma species, with genetic distances of 4.34 % and 4.33-4.58 %, respectively. This study marks the first report of tick-associated Trypanosoma in Malaysia and underscores significant research gaps regarding trypanosome interactions with tick hosts in the region.

Use of thermal drone in detection and assessment of larval mass temperature in decomposed rabbit carcasses.

Manual ground searches and cadaver dogs are traditional methods for locating remains, but they can be time- and resource-intensive, resulting in the decomposition of bodies and delay in victim identification. Therefore, thermal imaging has been proposed as a potentially useful tool for detecting remains based on their temperature. This study investigated the potential of a novel search technique of thermal drones to detect surface remains through the detection of maggot mass temperatures. Two trials were carried out at Selangor, Malaysia, each utilizing 12 healthy male Oryctolagus cuniculus European white rabbits and DJI Matrice 300 RTK drone China, equipped with a thermal camera; Zenmuse H20T to record the thermal imaging footage of the carcasses at various heights (15, 30, 60-100 m) for 14 days for each trial. Our results demonstrated that the larval masses and corresponding heat emissions were at their largest during the active decay stage; therefore, all the carcasses were observable in thermal images on day 5 and remained until day 7. Statistical analyses showed that (1) no statistically significant differences in thermal images between clothed and unclothed subjects (p > 0.05); (2) 15 m above ground level was proven to be the optimal height, as it showed the greatest contrast between the carcass heat signature and the background (p < 0.005). Our data suggested the potential window of detection of thermal signatures was detectable up to 7 days post-deposition. This could be an important guideline for the search and recovery teams for operational implementation in this tropical region.

First report on adulticide susceptibility status of Aedes albopictus, Culex quinquefasciatus, and Culex vishnui from a pig farm in Tanjung Sepat, Selangor, Malaysia.

The present study aims to investigate the susceptibility status of Aedes albopictus, Culex quinquefasciatus, and Cx. vishnui collected from a pig farm in Tanjung Sepat, Selangor, toward 11 insecticides representing the classes of organochlorines, carbamates, organophosphates, and pyrethroids. The results of a World Health Organization adult mosquito bioassay revealed that Ae. albopictus, Cx. quinquefasciatus, and Cx. vishnui exhibited different susceptibility toward various insecticides. Overall, pyrethroids were able to induce rapid knockdown for all test mosquito species. The pyrethroids lambdacyhalothrin and etofenprox were able to cause high mortality (> 80%) of all 3 species. The findings of the present study will benefit local authorities in selecting appropriate dosage of insecticides to be used in mosquito control in this area.

Reporting beetles in a mummified human corpse in Malaysia: Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae) and Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae).

This case study reports on two unrecorded Coleopteran species found together on a human corpse in Malaysia. The mummified human remains were discovered in a house in Selangor, Malaysia. The pathologist confirmed that the death was due to a traumatic chest injury. Maggots, beetles, and fly pupal casings were found mainly on the front part of the body. Empty puparia of Diptera were collected during the autopsy and identified later as the muscid Synthesiomyia nudiseta (van der Wulp, 1883) (Diptera: Muscidae). Also, the insect evidence received included larvae and pupae of Megaselia sp. (Diptera: Phoridae). According to the insect development data, the minimum postmortem period was estimated by the time to reach the pupal developmental stage (in days). The entomological evidence included the first record of Dermestes maculatus De Geer, 1774 (Coleoptera: Dermestidae) and Necrobia rufipes (Fabricius, 1781) (Coleoptera: Cleridae), which have not previously been recorded on human remains in Malaysia.