Entomotoxicology.

Entomotoxicology is a relatively new branch of forensic entomology. The potential use of insects for detecting drugs and other toxins in decomposing tissues has been widely demonstrated. In death investigations, Diptera and other arthropods can be reliable alternate specimens for toxicological analyses in the absence of tissues and fluids normally taken for such purposes. Entomotoxicology also investigates the effects caused by drugs and toxins on arthropod development in order to assist the forensic postmortem interval estimates. However, several remarks on the limitations of entomotoxicology have been highlighted recently. In this paper, the implications for the practice of this forensic procedure are fully reviewed.

Morphine extraction in necrophagous insects remains for determining ante-mortem opiate intoxication.

To study the potential use of insects remains as toxicological indicators, we measured morphine in desiccated entomological materials using a radioimmunoassay method (Coat-A-Count Serum Morphine, Dade Behring, France) following enzymatic hydrolysis.First, enzymatic cuticle extraction of morphine (pronase digestion preceded by a 2h incubation with a dithiothreitol solution) was performed on various substrates (Calliphoridae puparial cases and desiccated adults, and desiccated pupae of Dermestidae) which were then tested to identify possible interferences with the radioimmunoassay procedure. This same procedure was performed on puparial cases and desiccated adults of Lucilia sericata (Diptera, Calliphoridae) previously reared on minced meat containing various morphine concentrations. Morphine was detected only in cuticle powder from insects reared on meats containing 100 and 1000mg/kg. Higher concentrations were measured in puparial cases. Rearings on psoas from eight heroin overdose victims confirmed previous experimental results. Remains of necrophagous insects, particularly puparial cases, are often preserved for a long time, and consequently can serve as late alternative specimens for toxicological analysis when suitable tissues are not available.

Effects of temperature and intraspecific interaction on the development of Dermestes maculatus (Coleoptera: Dermestidae).

Studies were conducted to determine development rates of of Dermestes maculatus DeGeer at temperatures of 15, 20, 25, 30, and 35 degrees C. No individuals completed development to the adult stage at 15 degrees C. For the other temperatures, survivorship ranged from 9.3% at 20 degrees C to 36% at 35 degrees C. Time required for development varied inversely with temperature from a mean of 89.7 d at 20 degrees C to 36.4 d at 35 degrees C. For specimens held individually, survivorship was higher at 25 and 30 degrees C, i.e., 83.2 and 60.2%, respectively. No specimens held individually at 35 degrees C survived past the first larval instar. Mortality during the egg stage at 25 and 30 degrees C was 4.52-5.23%, whereas mortality during the first instar was significantly higher for the individuals held at 30 degrees C and 100% for those at 35 degrees C. There was an inverse relation observed between larval density and both survivorship and mean adult weights.

Determination of drug levels in two species of necrophagous Coleoptera reared on substrates containing morphine.

Two species of necrophagous Coleoptera: Dermestes frischi (Dermestidae) and Thanatophilus sinuatus (Silphidae), were reared on substrates containing different amounts of morphine. Colonies of D. frischi were reared on rabbit carcasses which had been given 10, 20, and 40 mg/h of morphine hydrochloride via ear artery perfusion over a 3 h period prior to death. A fourth rabbit served as a control. T. sinuatus was reared on minced beef spiked with morphine hydrochloride to give concentrations of 1,000, 2,500, 5,000, and 10,000 ng/g and one control colony. These dosages were calculated to create tissue concentrations of morphine similar to those encountered in human deaths due to morphine overdose. Larvae. pupae, and adults (except for T. sinuatus) were analyzed for morphine content. All developmental stages of D. frischi were positive for morphine and concentrations correlated with cadaveric tissue concentrations during larval stages and to a lesser extent in the adult stage. For T. sinuatus, the best correlations were found in 2nd and 3rd instar larvae. This study demonstrates the potential for use of necrophagous Coleoptera, as well as Diptera larvae, as alternate specimens for toxicological analyses.

Immunohistochemical contribution to the study of morphine metabolism in Calliphoridae larvae and implications in forensic entomotoxicology.

Morphine was detected by immunohistochemistry on sections of third stage larvae of Calliphora vomitoria (Diptera, Calliphoridae) reared on minced beef meat previously treated with morphine hydrochloride. The detection was performed with an avidin-biotin-peroxidase-complex method. Positive specimens showed specific staining of the haemolymph and a more intense immunoreaction in an area located at the limit between exocuticle and endocuticle. These results constitute an evidence of morphine accumulation inside the cuticle of Diptera larvae during their development. During the pupariation, the larval cuticle is transformed into the sclerotized puparium. This study consequently points out the possibilities of analyzing empty pupariae when suitable tissues or living necrophagous insects are absent.

Epidermoptid mange in Laysan albatross fledglings in Hawaii.

Mange caused by the epidermoptid mite Myialges nudus (Acari: Epidermoptidae) is described in 31 dead fledgling Laysan albatrosses (Phoebastria immutabilis) from Midway Atoll (Hawaii, USA) sampled from 18 June to 10 July 1990 and from 21 June to 22 July 1991. This is the first record for this parasite from this host. Mites were collected from the skin; were located primarily in the stratum corneum; and were associated with mild to severe granulomatous inflammation, hyperkeratosis, dermal edema, ballooning degeneration of keratinocytes, neovascularization, and subdermal fibrosis. The severity of inflammation in some birds suggested that dermatitis due to M. nudus could be a significant cause of morbidity, or even mortality, in these birds.

Determination of drug levels in larvae of Protophormia terraenovae and Calliphora vicina (Diptera: Calliphoridae) reared on rabbit carcasses containing morphine.

Two species of blow flies (Diptera: Calliphoridae) were reared on tissues from rabbits administered different dosages of morphine. These species, Protophormia terraenovae and Calliphora vicina are among the first wave of insects colonizing a dead body. Two series of 3 rabbits were given dosages of 10, 20, and 40 mg/h of morphine over a 3 h period via ear artery perfusion. A morphine blood level plateau was attained after 1 h of perfusion. Two other rabbits were used as controls. Samples of tissues collected from rabbits using a coelioscopic technique were determined to have morphine concentrations similar to those encountered in human overdoses and were correlated with dosages of morphine administered. All samples from control rabbits were negative for morphine. Larvae and puparia of both species were regularly collected from each rabbit for toxicological analysis. Concentrations of morphine in larvae reared on rabbit carcasses containing morphine were significantly lower than concentrations found in the tissues. There was a decrease in concentration in morphine observed in transition from feeding 3rd instar larva to puparium. A correlation between larval concentration and tissue concentration was found only in feeding 3rd instar larvae.

Comparison of patterns of decomposition in a hanging carcass and a carcass in contact with soil in a xerophytic habitat on the Island of Oahu, Hawaii.

Decomposition studies were conducted to determine differences in rates and patterns of decomposition of carcasses hanging and exposed on the surface of the soil. These studies were conducted between 17 October and 17 December 1997 inside of Diamond Head Crater on the island of Oahu, Hawaii. The animal model was the domestic pig. Sus scrofa. The rate of biomass removal from the hanging carcass was significantly slower than that observed for the control carcass during the bloat and decay stages of decomposition. Internal temperatures for the control carcass were elevated above the ambient air temperatures during the earlier stages of decomposition (bloated and decay), while those recorded for the hanging carcass approximated the ambient air temperatures. There was a greater diversity of arthropod species recorded and numbers of individuals observed were higher for the control carcass. A significant site of arthropod activity was observed on the surface of the soil immediately under the hanging carcass and this became the primary site of arthropod activity as decomposition progressed.

Decomposition patterns in terrestrial and intertidal habitats on Oahu Island and Coconut Island, Hawaii.

Decomposition studies were conducted at two sites on the Island of Oahu, Hawaii, to compare patterns of decomposition and arthropod invasion in intertidal and adjacent terrestrial habitats. The animal model used was the domestic pig. One site was on Coconut Island in Kaneohe Bay on the northeast side of Oahu, and the second was conducted in an anchialine pool located at Barber's Point Naval Air Station on the southwest shore of Oahu. At both sites, the terrestrial animal decomposed in a manner similar to what has been observed in previous studies in terrestrial habitats on the island of Oahu. Rate of biomass depletion was slower in both intertidal studies, and decomposition was primarily due to tide and wave activity and bacterial decomposition. No permanent colonization of carcasses by insects was seen for the intertidal carcass at Coconut Island. At the anchialine pool at Barber's Point Naval Air Station, Diptera larvae were responsible for biomass removal until the carcass was reduced below the water line and, from that point on, bacterial action was the means of decomposition. Marine and terrestrial scavengers were present at both sites although their impact on decomposition was negligible. Five stages of decomposition were recognized for the intertidal sites: fresh, buoyant/floating, deterioration/disintegration, buoyant remains, and scattered skeletal.

A simple method for fume cupboard performance assessment.

The performance of a fume cupboard is determined by a complex interaction of factors which are time consuming and expensive to determine. This paper describes a simple and practical means of ranking, and assessing fume cupboard installations that can help to discharge managerial responsibility for a 'safe' environment. The method also gives an economically viable and technically defensible system for assessing fume cupboard performance as part of upgrading exercises or performance audits. The assessment strategy uses flow visualisation techniques and measurements of inflow air velocity as well as overall condition evaluation to rank performance and identify poor performing cupboards. The method has been used to carry out a condition and performance survey of 199 fume cupboards, both aerodynamic and box-type designs, in an academic institution. The results of this survey are presented which not only highlight performance characteristics but also provide insights into user attitudes and knowledge of fume cupboard operation and performance. It is suggested that surveys such as this could be helpful in training programmes for laboratory workers to enable them to optimise the use of fume cupboards.

Computational fluid dynamics as a method for assessing fume cupboard performance.

A commercially available computational fluid dynamic (CFD) software program, specific for HVAC systems, was used to study the performance of an aerodynamic fume cupboard. The numerical results showed good qualitative agreement with physical measurements giving confidence in the CFD model to simulate and predict overall fume cupboard performance. However, there were some quantitative differences specifically around 'aerodynamic' features that could not be accurately simulated by the software code. The CFD model was clearly able to demonstrate differences in performance between good and bad cupboard designs, and show the importance of using rear baffles and lipfoils. It also showed the importance of good design features when a 'worker' was standing against the front edge or when there were draughts in front of the aperture. The computer model was used to simulate the gas tracer containment test method described in BS 7258 (1994) [Laboratory Fume Cupboards], and had a much greater sensitivity than the recommended physical measuring instruments. The results given in this paper demonstrate the potential for using a commercially available software package for the optimisation of fume cupboard design and testing. It also indicates the economy of using CFD compared with building a prototype and testing a model.

A method for determining the heat transfer and water vapour permeability of patient support systems.

The formation of pressure ulcers can be exacerbated by a breakdown in the integrity of the patient's skin caused by poor maintenance of the skin microclimate. Patient support systems (PSSs-specialised beds, mattresses, chairs, cushions and pads) play an important role in the dissipation of heat and moisture away from the skin/support interface which is necessary in order to maintain the physiological skin microclimate. This paper reports a laboratory method and theory for the simultaneous measurement of the heat and water vapour dissipating properties of PSSs. The results demonstrate that the method is extremely selective, exhibiting very significant differences between the PSSs tested. It also shows that assessing PSS covers independently does not necessarily indicate the overall performance of the complete PSS.

Two new species of chiggers (Acari: Trombiculidae and Leeuwenhoekiidae) from Iran.

Odontacarus khanjani Goff & Saboori (Leeuwenhoekiidae) and Neotrombicula iranensis Goff & Saboori (Trombiculidae) were described as new. Both species were collected as unengorged larvae on alfalfa plants, Medicago sativa, in western Iran.

Arthropod succession patterns onto burnt carrion in two contrasting habitats in the Hawaiian Islands.

Decomposition studies were conducted using carcasses of domestic pigs, Sus scrofa L., one burned and the other unburned (the control) to determine effects of burning on arthropod succession patterns. The burnt carcass corresponded to a CGS level #2 burn victim. The studies were conducted in two contrasting habitats, both on the island of Oahu. The first was conducted in a xerophytic habitat from 1 Sept. 1995 through 1 Oct. 1995 while the second was conducted in a rainforest habitat from 29 April 1996 to 28 May 1996. No marked differences were noted in arthropod fauna present or the duration of the stages of decomposition between the carcasses at either site. The major oviposition by flies of the family Calliphoridae occurred one day earlier on the burnt carcass than the control carcass at Diamond Head and four days earlier at Lyon Arboretum. This resulted in all successional waves onto the burnt carcass occurring one day earlier at Diamond Head and four days earlier at Lyon Arboretum. These differences could alter a postmortem interval estimate based on arthropod succession patterns by up to 24 hours and 4 days, respectively.

Estimation of postmortem interval based on colony development time for Anoplolepsis longipes (Hymenoptera: Formicidae).

The postmortem interval for a set of human remains discovered inside a metal tool box was estimated using the development time required for a stratiomyid fly (Diptera: Stratiomyidae), Hermetia illucens, in combination with the time required to establish a colony of the ant Anoplolepsis longipes (Hymenoptera: Formicidae) capable of producing alate (winged) reproductives. This analysis resulted in a postmortem interval estimate of 14 + months, with a period of 14-18 months being the most probable time interval. The victim had been missing for approximately 18 months.

The genus Hexidionis (Acari:Trombiculidae) with the description of a new species from Texas.

Hexidionis garfieldi is described as new from specimens collected off a domestic cat. Felis silvestris f. catus Schreber, in Corpus Christi, TX. The genus Hexidionis Vercammen-Grandjean & Loomis, 1967, is rediagnosed and a key to the 11 included species given.

Arthropod succession on exposed carrion in three contrasting tropical habitats on Hawaii Island, Hawaii.

Decomposition studies were conducted using domestic pig carcasses to determine arthropod succession patterns on exposed carrion for the island of Hawaii. The carcasses were placed in upland forest and woodland (1,877 m), rainforest (1,169 m) and midelevation woodlands (646 m) habitats. Marked differences in species composition, rates of biomass removal, and succession patterns were observed between these 3 sites. These results also differed from patterns observed during previous decomposition studies conducted on the island of Oahu.

Effects of 3,4-methylenedioxymethamphetamine in decomposing tissues on the development of Parasarcophaga ruficornis (Diptera:Sarcophagidae) and detection of the drug in postmortem blood, liver tissue, larvae, and puparia.

Larvae of Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae) were reared on tissues from rabbits administered different dosages of 3,4-methylenedioxymethamphetamine to study the effects of this drug on the development of this insect species. The rabbits were given 11, 22.5, and 67 mg of the drug via ear vein infusion. These dosages correspond to a 0.5, 1.0, and 2.0 median lethal dose. Larvae from colonies fed on tissues from the rabbit receiving 67 mg and the control developed more rapidly from hours 24 through 114. The period required for completion of larval development was significantly shorter for the larvae from the colony fed on liver tissues from the rabbit receiving the 67 mg dosage. This colony also had the lowest total mortality rate during development. No significant differences were observed among the colonies in the duration of the puparial period. Analyses by liquid chromatography/mass spectrometry of the larvae and empty puparial cases following base extraction detected the drug in quantities directly related to the dosage of the drug administered to the rabbits serving as a food source. These results have implications for the determination of time since death when gauged by the development of this insect species.

External ophthalmomyiasis, a disease established in Hawaii.

External ophthalmomyiasis, usually caused by the sheep nasal bot fly, Oestrus ovis L., is characteristically a benign disorder in humans, but may rarely cause severe complications. It occurs on most of the inhabited Hawaiian islands, and is more common than indicated by previously published reports. A typical case is presented along with the fly's life cycle, clinical features, and management.