Biomedical subjects
Publications and source records attributed to M L Goff.
The genus Parasecia Loomis, 1966, is redefined, and Parasecia bulbocalcar Goff is described as new from specimens collected off a Yellow-shouldered Bat, Sturnia ludovici Anthony, taken in Morelos, Mexico. A key to the 15 species of Parasecia is provided.
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A computer algorithm, implemented in the BASIC language, is presented for calculating the postmortem interval (PMI) from arthropod successional data. Entomology-assisted determination of the PMI promises to be a reliable technique in cases of homicide, suicide, accidental death, and unattended death due to natural causes. The program requires, as input, the identity of arthropod taxa recovered from human remains in a death scene investigation and machine-readable data on carrion-associated arthropod taxa and their known successional patterns of activity for the same geographical area. The program performs rapid comparisons of these lists and, on output, calculates an upper and lower estimate of the PMI, identifies the definitive taxa for these limits, and determines if the remaining corpse taxa have known successional patterns that are consistent for this estimate. An alternate output is provided if one or more corpse taxa do not overlap all the others at any single time in the succession. In that event, the user is prompted to recheck the identity of the non-overlapping taxon or taxa or reevaluate the environmental circumstances surrounding the case in question. Results of the analysis are saved to an ASCII file for output to a printer for making paper copies useful for the entomologist's Case Study Final Report. This program may make possible wider use of this technique in law enforcement and medical investigator offices that utilize both forensic entomologist expertise and IBM PCs (or compatible computers).
Larvae of Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae) were reared on tissues from rabbits administered different dosages of methamphetamine to study the effects of this drug on development of this species. The rabbits were given 37.5, 71.4, and 142.9 mg of methamphetamine via ear vein infusion. From Hours 30 to 60, larvae feeding on tissues from rabbits receiving 71.4 and 142.9 mg of methamphetamine developed more rapidly than larvae from the control colony and those feeding on tissues from the rabbit receiving 37.5 mg of methamphetamine. The time required for pupariation was significantly greater for colonies fed on tissues from methamphetamine-dosed rabbits than for the control. These differences were sufficient to alter postmortem interval estimates based on larval development by up to 18 h and estimates based on puparial development by up to 48 h. The presence of methamphetamine or amphetamine could not be detected in Diptera larvae in this experiment using radioimmunoassay techniques, as there was a nonspecific reaction, resulting in a false positive.
Two new species of chiggers are described from mammals collected in Fazenda Agúa Limpa, Federal District, Brazil: Trombewingia brasiliensis from Bolomys lasiurus and Parasecia lasiurus from B. lasiurus and Oxymycterus sp.
Decomposition studies were conducted using two carcasses of domestic pigs, Sus scrofa L., 8.4 kg and 15.1 kg in weight, to determine the effects of carcass size on the rate of decomposition, composition of the arthropod fauna, and succession patterns. A total of 46 arthropod taxa were recovered during this study. No size-related differences were observed between carcasses with respect to composition of the arthropod fauna or patterns of succession. A greater number of arthropods were observed attracted to the 15.1-kg carcass, and the rate of decomposition observed was more rapid for the 15.1-kg carcass than for the 8.4-kg carcass. Internal temperatures of the 8.4-kg carcass were more directly related to external ambient temperatures during the fresh and bloated stages of decomposition. During the decay stage, both carcasses generated internal temperatures significantly above ambient temperatures. Following this stage, internal temperatures fell to approximate ambient temperatures during the postdecay and remains stages.
Second instar larvae of the fly Chrysomya megacephala (Diptera, Calliphoridae) were recovered from the diapers of a 16-month-old child abandoned by her mother on Oahu, Hawaii. The development of these larvae indicated a minimum period of 23.5 h of exposure prior to discovery of the child. Larvae of this species of fly are not normally associated with living tissues in Hawaii, but rather with feces and remains during the early stages of decomposition. Had the child in this case died and data not been provided detailing the site of infestation, the postmortem interval estimated would have been significantly longer than was actually the case, because of the development of the larvae inside the diapers of the living child. The need for caution in cases involving deaths of infants, the elderly, and individuals not capable of caring for themselves is stressed.
A comparison of insects collected from 35 cases of decomposing remains on the island of Oahu, Hawaiian Islands (14 from indoor situations and 21 from outdoors), yielded a total of 22 species of insects in 3 orders and 12 families. Of these, five species were recovered in both indoor and outdoor situations. Remains recovered indoors had a greater variety of Diptera larvae associated with them, while remains discovered outdoors had a greater variety of Coleoptera species present. Some species of insects were restricted to remains discovered indoors, while others were found only associated with remains in outdoor situations. Knowledge of the species of insects associated with different habitats may serve to provide information concerning the history of the remains.
Larvae of the flesh fly Boettcherisca peregrina (Robineau-Desvoidy) were reared on the tissues of rabbits to study the effects of heroin on the development rates of this species. The rabbits were given 6, 12, 18, and 24 mg of heroin by cardiac puncture. From Hours 18 to 96, larvae feeding on tissues containing heroin (as morphine) developed more rapidly than those feeding on tissues from the control. The time required for pupation was significantly greater for colonies fed on tissues from heroin-dosed rabbits than for the control colony. The differences observed in the rates of development were sufficient to alter postmortem interval estimates based on larval development by up to 29 h and estimates based on pupal development by 18 to 38 h.
A postmortem interval of 34 to 36 days was established for remains recovered on the island of Oahu, Hawaii, based on interpretations of patterns of arthropod succession on the remains. This interval was primarily based on the presence of adult specimens of Philonthus longicornis (family Staphylinidae), mature larvae of Piophila casei (family Piophilidae), and empty puparial cases of Chrysomya rufifacies (family Calliphoridae). Species and developmental stages of two additional Coleoptera species and three additional Diptera species were also present, which was consistent with the estimated interval, although not definitive.
Rearing of Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) in pure cultures at seven different population densities (larvae per gram of liver) demonstrated an inverse relationship between density and the duration of the larval stage. In pure cultures, larval mortality rates decreased with increasing density until an optimum density was reached (8 larvae/g liver for C. megacephala and 10 larvae/g liver for C. rufifacies), then decreased directly with density. Puparial and adult weights varied inversely with density for both species in pure cultures. Internal feeding mass temperatures were above ambient temperatures for all cultures, with maximum temperatures recorded in cultures with 20 and 40 larvae/g liver for G. rufifacies and C. megacephala, respectively. In paired encounters, larvae of C. rufifacies were cannibalistic and predatory on C. megacephala larvae after the first instar. In mixed cultures of these two species, the larval mortality of C. rufifacies remained relatively stable, whereas the larval mortality of C. megacephala increased directly with population density.
Larvae of the flesh fly, Boettcherisca peregrina (Robineau-Desvoidy), were reared on the tissue of rabbits to study the effects of cocaine and benzoylecognine on development rates. The rabbits were given 35, 69, and 137 mg of cocaine through cardiac puncture. From hours 30 to 70, larvae developed more rapidly on tissue containing cocaine, benzoylecognine, or both, from rabbits injected with 69 and 137 mg of cocaine than on tissue from rabbits injected with 35 mg of cocaine or no cocaine. Total development times required for pupation and adult eclosion were shortened correspondingly. Differences observed in the rate of development were sufficient to alter postmortem interval estimates based on larval development in decomposing human tissues by up to 24 h.
Colicus spinosus Goff & Gettinger, n. sp., is described from Marmosa agilis. Quadraseta brasiliensis Goff & Gettinger, n. sp., is described from Marmosa agilis, Monodelphis americana, and Oryzomys capito. All specimens were collected in central Brazil. The diagnosis of the genus Arisocerus Brennan, 1970, is corrected to describe the setation of the palpal tarsus as 7BS rather than 6BS as listed in the original description.
Deaths as a result of organophosphate poisoning are usually detected by analysis of body fluids and tissues for the presence of the toxic agent. These procedures present particular difficulties when performed on remains in an advanced stage of decomposition. Malathion poisoning was suspected in a case in which the remains were in an advanced stage of decomposition and the presence of malathion was confirmed by analyses of gastric content and body fat. Two species of fly larvae, Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart), were present on the remains. A sample of these larvae was analyzed for malathion content. A total of 574 micrograms of malathion was detected in 0.26 g of pooled larvae, or a level corresponding to 2050 micrograms/g of larvae. Presence of organophosphates in arthropod larvae has not been documented previously and the analysis of larvae from decomposing remains may prove a useful technique for detection of these toxicants in decomposing remains.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.