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Scheme for Investigating Cases of Death due to Traumatic Injuries
Published in Paul T. Jayaprakash, Crime Scene Investigation and Reconstruction, 2023
Being active during the daytime, the Calliphorid flies oviposit on dead bodies almost immediately after death unless physical barriers prevent their access to the dead body. The time taken for the different stages in their life cycle remains constant for a given ambient temperature, and thus is considered a reliable indicator when assessing the time since death in decomposed dead bodies. During less rainy seasons, C. megacephala are seen ovipositing on animal models on the first day; the first instar larvae hatching out on the second day; and the larvae of the second instar, third instar, and the prepupal (migrating larvae) being noted on the third, fourth, and fifth days, respectively. Pupae were noticed on the sixth day (during April–June at mean ambient temperature 28.25 ± 0.89ºC in Malaysia) (Mahat et al., 2009). Diagrammatic representation of the life cycle of C. megacephala until reaching the pupae stage indicating the minimal duration observed in Malaysia is shown in Figure 5.60. The eggs of both these species are seen in batches, and the first instar larvae do not exhibit particular spiracle morphology. The posterior spiracle of the second instar larvae have two slits while that of the third instar larvae have three slits (PS2 and PS3 in Figure 5.60). The SOCOs may note that the differences in spiracle morphology can be observed using a stereo microscope and thus can be used for inferring the larval growth stages in the crime scene itself. Similarly, the migrating stage can be recognized by the larval mass moving away from the dead body seeking to pupate.
Fly Larvae in Humans (Myiasis)
Published in Jerome Goddard, Public Health Entomology, 2022
Most clinical myiasis samples are from facultative myiasis originating from blow fly (Diptera: family Calliphoridae) larvae being found in a patient’s nose, ear, rectum, or pus-filled wound. If the site is a natural orifice, there is or was usually a lesion or infection that proved attractive to the female fly. Many times, the patient is an invalid and unable to care for himself or herself. These cases of myiasis are usually not life threatening because the larvae rarely invade healthy tissue. Identification of the larvae in clinical samples is fairly easy to the family level (blow fly, house fly, flesh fly, etc.) using algorithms, keys, and illustrations available on the Internet. For example, house fly larvae have light brown posterior spiracles located on flat or rounded areas without any ring of soft protuberances around them (Figure 21.8). Blow fly and flesh fly larvae, on the other hand, have their spiracles set in depressions surrounded by a ring of soft fleshy protuberances. Patients with myiasis should be questioned about their recent travel history. Occasionally, human bot fly or screw-worm myiasis occurs in travelers returning from tropical countries. One woman I knew complained about a “boil” occurring behind her ear after a trip to Belize. She claimed she could feel or sense a “clicking” sound inside the boil. Eventually she was seen by a physician who diagnosed human bot fly myiasis (Figure 21.4). Apparently, she really was sensing the larva as it moved or fed in the tissues near her ear.
Flies (That Might Cause Myiasis)
Published in Gail Miriam Moraru, Jerome Goddard, The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Gail Miriam Moraru, Jerome Goddard
As in other types of myiasis, the only known therapeutic procedure, other than applying local palliatives, is the direct removal of the maggots (surgically, if necessary) and treatment to prevent or control secondary infection. Service19 observed that a standard method for Tumbu larvae removal is to cover the small hole in the swelling with medicinal liquid paraffin. This prevents the larva from breathing through its posterior spiracles and forces it to wriggle a little further out of the swelling to protrude the spiracles. In doing so, it lubricates the pocket (in the skin) and the larva can then be extracted by gently pressing around the swelling. Care must be taken not to break or damage the larva to prevent an intense immune response.
UV-C radiation during the pupal stage affects morphological changes of wings in Tribolium castaneum (Col; Tenebrionidae)
Published in International Journal of Radiation Biology, 2019
Jatuporn Tungjitwitayakul, Thippawan Yasanga, Nujira Tatun
Generally, the forewings (elytra) of beetles are gradually reduced in width towards the distal ends (Kukalova 1969). A specific shape of the elytra is needed to form a tight seal between both sides of the elytra as well as between the wings and dorsal sides of the insect’s body. Sealing between the left and right elytra is required for protective function (Crowson 1981). The morphometric analysis indicated that the shape and size of the elytra and hindwings were altered by UV-C. UV-C caused several abnormalities in the elytra and hindwings of T. castaneum, which were classified into 9 grades (G1–G9) based on the severity. The abdomen of adults (G6 in Figure 2) was uncovered because the elytra were split and the hindwings were unfolded. This suggests that water was lost from the uncovered abdomen, which may be one of the factors causing adult mortality after UV-C radiation. Previous reports showed that water can be lost directly through the integument in insects and also during respiration through the spiracles (Gibbs 2011). Elytra have important roles in water retention in beetles that live in dry areas (Chown et al. 2006; Schilman et al. 2008). Linz et al. (2016) noted water loss through the very thin cuticle of dorsal abdomen in Tribolium when the elytra were surgically removed, and the beetles without elytra had high mortality.
Modulation of neuromuscular synapses and contraction in Drosophila 3rd instar larvae
Published in Journal of Neurogenetics, 2018
Kiel G. Ormerod, JaeHwan Jung, A. Joffre Mercier
Leucokinin (LK), a member of the kinin peptide family, is encoded in one Drosophila gene (Terhzaz et al., 1999) and is expressed in larvae in abdominal (ABLK) neurons that send axon terminals to muscle 8 (de Haro et al., 2010; Landgraf, Sánchez-Soriano, Technau, Urban, & Prokop, 2003). These terminals contain dense core vesicles, lie near spiracles and are not far from Malpighian tubules. This location might allow LK to act as a co-transmitter on muscle 8 or elicit paracrine effects on spiracles or Malpighian tubules. The ABLK cells also express serotonin receptors that mediate serotonin’s ability to suppress rearing and reduce turning during larval crawling (Okusawa, Kohsaka, & Nose, 2014). Possible effects of LK on muscle warrant further study.
Neotropical freshwater stingrays (Chondrichthyes – Potamotrygoninae): biology, general features and envenomation
Published in Toxin Reviews, 2020
Juliana Luiza Varjão Lameiras, Oscar Tadeu Ferreira da Costa, Maria Cristina Dos-Santos
Of the aquatic animals, fishes are the most important medically (Brasil 2001). The main venomous fishes include stingrays, which, although not aggressive, cause many envenomations in regions where they are endemic (Halstead 1966, Junghanss and Bodio 2006, Magalhães et al.2008). Venomous stingrays belong to class Chondrichthyes (cartilaginous fishes), order Myliobatiformes (Nelson et al.2016) and are the only rays with stingers on their tail (Lovejoy 1996, Carvalho et al.2004, McEachran and Aschliman 2004). They have flat dorsal and ventral surfaces: the eyes and spiracles are located in the dorsal region (Figure 1(A)), and there are five pairs of gill slits and pelvic fins in the ventral region (Figure 1(B)).