Apparent Death Research Articles

Comparative pathogenicity of duck hepatitis A virus genotype 3 in different duck breeds: Implications of the diagnosis and prevention of duck viral hepatitis

Duck hepatitis A virus (DHAV) infection in ducklings causes acute hepatitis with considerable economic losses. In this study, Pekin and Muscovy duckling flocks (n=9) suffering from high mortality and hepatic lesions were examined by RT-PCR for DVHA. 44.4 % (4/9) of samples were positive for DHAV (5′ UTR region), of which 100 % (4/4) were DVHA-3 (VP1 gene). VP1 sequencing and phylogenetic analysis of an isolate originated from Muscovy ducklings showed that it shared 96.8 % −100 %, 88.5–89.2 %, and 86.5–88.2 % nucleotide similarity (ns) with the Egyptian, Korean-Vietnamese, and Chinese DVHA-3 strains, respectively. It was distinguished from the DHAV-1 vaccine (67.6 % ns). The sequenced DVHA-3 isolate was used to experimentally infect 5-day-old Pekin and Muscovy ducklings vs. control groups. No apparent clinical signs or deaths were reported in the experimentally-infected groups. Pekin ducklings showed greater cloacal viral shedding than Muscovy until the 6th dpi (P<0.05). DVHA-3 induced a significant rise in IFN-β and IL-1β serum levels, where Muscovy ducklings' levels were higher than Pekin ducklings. Among the biochemical parameters, AST was only increased on the 4th dpi in both breeds vs. control (P<0.05). Compared to Muscovy ducklings at 2, 4, and 6 day post infection (dpi), the infected Pekin group had lower lipase levels (P≥0.05, p<0.05, and p<0.05, respectively), while ALT was higher at 4 and 6 dpi (P<0.05). The histopathological lesions supported the gross lesions, and their scores were dominant at 2 and 4 dpi in both breeds. At 6 and 8 dpi, Pekin showed more severe histopathological changes compared to Muscovy for the liver, heart, brain, and intestines; the pancreas, kidney, and lung showed the opposite pattern. In conclusion, Pekin ducklings displayed distinct DHAV-3 infection results from Muscovy ducklings, and more research utilizing a variety of DHAV-3 strains has to be carried out.

The Slithering Dead: Does locomotor performance affect post-capture death feigning in dice snakes (Natrix tessellata, Laurenti 1768)?

Abstract Functional constraints between different types of antipredator behavior should be common, especially if they are on the opposite sides of the behavioral spectrum such as flight and post-capture immobility. We examined a potential compromise between post-capture immobility displays and sprint speed in dice snakes (Natrix tessellata), using a field-based approach. We sampled snakes (N = 238) from two populations: from a dense island population free of mammal predators, and from a less dense mainland population, preyed upon by both bird and mammal predators. We explored the effects of sexual maturity, temperature, body size, presence of palpable food in the gut, and injuries on the occurrence and duration of post-capture immobility as well as sprint speed. Our results confirm the existence of functional constraints between locomotor performance and post-capture immobility in dice snakes. Faster dice snakes start escaping promptly after release, while slower individuals utilize more passive antipredator behaviors such as death feigning. Local adaptations seem to have great influence on behavioral compromise, since the mammal-free island population exhibited a higher incidence of post-capture immobility and a significantly lower sprint speed, compared to the less dense mainland population. Additionally, immature individuals tended to avoid death feigning and their post-capture immobility lasted shorter compared to adult individuals. It remains to be seen how individuals adjust their behavior to accomodate locomotor constraints, and in which specific phases of the predator-prey interaction these adjustments occur.

PTEN DELETION IN THE ADULT DENTATE GYRUS INDUCES EPILEPSY.

Embryonic and early postnatal promotor-driven deletion of the phosphatase and tensin homolog (PTEN) gene results in neuronal hypertrophy, hyperexcitable circuitry and development of spontaneous seizures in adulthood. We previously documented that focal, vector-mediated PTEN deletion in mature granule cells of adult dentate gyrus triggers dramatic growth of cell bodies, dendrites, and axons, similar to that seen with early postnatal PTEN deletion. Here, we assess the functional consequences of focal, adult PTEN deletion, focusing on its pro-epileptogenic potential. PTEN deletion was accomplished by injecting AAV-Cre either bilaterally or unilaterally into the dentate gyrus of double transgenic PTEN-floxed, ROSA-reporter mice. Hippocampal recording electrodes were implanted for continuous digital EEG with concurrent video recordings in the home cage. Electrographic seizures and epileptiform spikes were assessed manually by two investigators, and corelated with concurrent videos. Spontaneous electrographic and behavioral seizures appeared after focal PTEN deletion in adult dentate granule cells, commencing around 2 months post-AAV-Cre injection. Seizures occurred in the majority of mice with unilateral or bilateral PTEN deletion and led to death in several cases. PTEN-deletion provoked epilepsy was not associated with apparent hippocampal neuron death; supra-granular mossy fiber sprouting was observed in a few mice. In summary, focal, unilateral deletion of PTEN in the adult dentate gyrus suffices to provoke time-dependent emergence of a hyperexcitable circuit generating hippocampus-origin, generalizing spontaneous seizures, providing a novel model for studies of adult-onset epileptogenesis.

Hereditary nature of death-feigning frequency in a parasitoid wasp Heterospilus prosopidis using sib analysis.

Death feigning, a state of immobility observed in many animals in response to external stimuli, is an anti-predator behaviour. Although previous studies showed that death-feigning behaviours are quantitative genetic traits, the knowledge of the heritable basis of death-feigning behaviour is lacking. To investigate the heritable basis of death-feigning behaviour, we used 3 laboratory strains of a braconid parasitoid wasp, Heterospilus prosopidis. The heritable basis using half-sib analysis, and the effects of different geographical backgrounds, rearing conditions in the laboratory, and host age were evaluated. The results of the half-sib analysis showed that the frequency of death feigning varied among sires, suggesting a certain extent of additive genetic variance. Also, the frequency of death feigning varied between geographical backgrounds and among strains. Death-feigning frequency was not affected by the age of the host. Our findings highlight the importance of genetic factors underlying the basis of the death-feigning behaviour and provide support for the genetic alterations of traits from the perspective of evolution in various animal species.

Diagnosis of apparent death and resuscitation techniques in 18th century Spain: a historical analysis

Diagnosis of apparent death and resuscitation techniques in 18th century Spain: a historical analysis

Mate search or predation avoidance? Sex pheromone interrupts death feigning of males in the sweet potato weevil Cylas formicarius

Death feigning is hypothesized to be an anti-predator behavior in which prey is temporarily immobilized in response to external stimuli. While death feigning may be an effective predator-defense strategy, there may be trade-offs in terms of energy and time for finding food and/or mating. The duration of death feigning is regulated by the balance of various selection pressures, and its duration is influenced by many internal and environmental factors. However, little is known about the factors that influence arousal from death-feigning behavior. Sex pheromones are important semiochemicals that affect reproductive success and may influence the duration of death-feigning behavior. In this study, we aimed to investigate the effects of sex pheromones on the death-feigning behavior of the sweet potato weevil (Cylas formicarius) by conducting laboratory experiments. The results showed that males had a significantly shorter death-feigning duration in the presence of sex pheromones because it aroused them from their death-feigning behavior, but females were unaffected. This is the first study to show that sex pheromones alter death-feigning behavior. The results of this study elucidate the factors influencing predator-avoidance behavior and reveal the impact of death-feigning behavior on prey reproduction under predation pressure.

Death Feigning in Larvae of Scorpionflies (Mecoptera: Panorpidae): Frequency and Postural Changes Based on Larval Instars

AbstractDeath feigning is thought to have evolved primarily as a predator avoidance behavior, and has been reported in 10 of the 31 orders of insects. However, there have been no reports of death-feigning behavior in Mecoptera species. We found that larvae of two scorpionfly species, Panorpa japonica and P. pryeri, showed death feigning in response to external stimuli by brush poking stimulation. First, we examined the frequencies of death-feigning postures. The two species showed two different postures of death feigning, “straight” and “ball.” Most of the 1st instar larvae of P. japonica and P. pryeri adopted the straight death-feigning posture. Next, we examined duration of death feigning. As the larval instar progressed, the death-feigning posture shifted from straight to ball in both Panorpa species. In P. japonica, the longest durations of death feigning were found in the 2nd to 3rd instars, while the longest duration of death feigning was found in the late 4th instar in P. pryeri larvae.

A Young Woman with Apparent Brain Death

A Young Woman with Apparent Brain Death

Synergistic effects of musking and autohaemorrhaging on the duration of death feigning in dice snakes (Natrix tessellata).

Predation exerts a significant selection pressure on prey, shaping a multitude of traits that serve as antipredator defences. In turn, natural selection could favour combinations of antipredator defences with synergistic effects that enhance prey survival. An especially interesting antipredator defence is death feigning (DF), present in a wide variety of taxa and usually characterized by the prey lying motionless often along with defaecation, musking and autohaemorrhaging (AH). All these aspects of the DF display should work in conjunction with one another, intensifying the overall effect of the display and in turn facilitating quicker escape. To confirm this hypothesis, we tested 263 dice snakes (Natrix tessellata) directly in the field. We noted the occurrence of smearing faeces, musk and AH, and we measured the duration of DF, expecting to see a negative association between the occurrence of these behaviours and the duration of DF. Our results affirm our hypothesis: dice snakes that smeared themselves in musk and faeces prior to DF and had AH during DF spent significantly less time in DF. Our results highlight the functional integration of antipredator behaviours across different phases of predator-prey interactions, emphasizing the need for future research to prioritize studying the sequential display of behaviours.

Flexible TAM requirement of TnpB enables efficient single-nucleotide editing with expanded targeting scope

TnpBs encoded by the IS200/IS605 family transposon are among the most abundant prokaryotic proteins from which type V CRISPR-Cas nucleases may have evolved. Since bacterial TnpBs can be programmed for RNA-guided dsDNA cleavage in the presence of a transposon-adjacent motif (TAM), these nucleases hold immense promise for genome editing. However, the activity and targeting specificity of TnpB in homology-directed gene editing remain unknown. Here we report that a thermophilic archaeal TnpB enables efficient gene editing in the natural host. Interestingly, the TnpB has different TAM requirements for eliciting cell death and for facilitating gene editing. By systematically characterizing TAM variants, we reveal that the TnpB recognizes a broad range of TAM sequences for gene editing including those that do not elicit apparent cell death. Importantly, TnpB shows a very high targeting specificity on targets flanked by a weak TAM. Taking advantage of this feature, we successfully leverage TnpB for efficient single-nucleotide editing with templated repair. The use of different weak TAM sequences not only facilitates more flexible gene editing with increased cell survival, but also greatly expands targeting scopes, and this strategy is probably applicable to diverse CRISPR-Cas systems.

Tongue flicking heralds flight behaviour following passive antipredator displays in dice snakes

AbstractWhen captured, many prey respond by biting the predator or struggling to get free. However, one indirect escape option is death feigning (DF), in which complete immobility supposedly “tricks” the predator into abandoning its meal. But lying motionless and exposed to a predator is dangerous; therefore, individuals should optimize DF occurrence and duration. We captured colour polymorphic dice snakes (Natrix tessellata, Natricidae) (N = 271) in the field and measured two behavioural responses: (1) the occurrence and duration of immobility/DF; (2) the number of tongue‐flicking sequences (TF). Tongue flicking is an essential component of a key sensory mechanism to check the safety of the environment before attempting escape. We experimentally assessed the relationship between these two behaviours and the effects of phenotypic characteristic of snakes on the occurrence and duration of immobility and of TF. Snake phenotype had multiple effects. Gravid females avoided DF and displayed more TF sequences during the tests compared to non‐gravid females and males. Blotched snakes stayed immobile longer than green and melanistic snakes. Larger individuals remained in DF for longer and showed fewer TF sequences than smaller individuals. Snakes burdened with a recent meal postponed fleeing and displayed more TF sequences than snakes without food. Finally, snakes showing more TF sequences postponed fleeing, which suggests that dice snakes assessed predatory risks and adapted escape behaviour to their risk status. Future studies should examine how individuals estimate the appropriate timing to shift from immobility to escape.

An Autopsy and Histopathology-based Study to Ascertain the Cause of Death of Brought Dead Cases

Abstract Background and Objectives: The cases of apparent natural deaths are encountered in the hospital casualties who are noted dead at the time of the first medical attention and as such are labeled as “Brought Dead.” These include the cases of sudden death, unexplained death, and unattended death. The cause of such deaths is reported in the literature to emanate principally from the cardiovascular system, though there are some documented geographical, racial, and other variations. In the present study, we endeavored to detect the cause of such natural deaths in terms of the disease and the organ system involved, in the deceased individuals of the contemporary Bengali population, with cases due to obvious unnatural causes being excluded. Materials and Methods: An observational, cross-sectional study with 105 (n = 105, male: 89, female: 16) study subjects of age group of 20–80 years, selected by systemic random sampling, from the brought dead subjects coming to the mortuary of the NRS Medical College and Hospital for medicolegal autopsy from April 2011 to March 2012, excluding cases having a history of the obvious unnatural event. Organ system-wise gross examination was done, followed by tissue sampling for histopathological examination. The case-wise findings were tabulated and analyzed for descriptive statistics using SPSS software. Results: In the present study, 89 cases were male (84.8%) and 16 cases were female (15.2%), which reflects a male: female ratio of 5.56:1. The dead bodies are mostly recovered from the footpaths (47 cases, 44%). Sixty-four (61%) cases are of known identity. In 54 cases out of 105 (51.4%), morbid pathology is detected in the respiratory system (RS), lobar pneumonia, and cavitary pulmonary tuberculosis being the most frequent disease entity, in both genders. Fifty-one years–sixty-five years is found to be the most commonly affected age group, in both genders. Interpretation and Conclusions: The present study shows that the most common organ system involved in brought dead cases is the RS, which is supported by a few Indian studies.

Moments in history illustrating approaches to the diagnosis of apparent death and the development of resuscitation techniques in the 18th century.

Moments in history illustrating approaches to the diagnosis of apparent death and the development of resuscitation techniques in the 18th century.

Drop dead! Female mate avoidance in an explosively breeding frog.

Males' and females' reproductive strategies may differ, potentially leading to sexual conflict. Increased efforts by males (harassment, forced copulation, intimidation) to gain access to females could even negatively affect female survival and thus lead to reproductive failure for both individuals. In anurans, a higher mortality risk of mating females has been reported in explosive breeding species. During these mating events, several males cling to a female, which are mostly unable to get rid of the unwanted males. This can lead to the female's death. From the literature, it seems that females of explosive breeding frogs have no means to reject unwanted males. Here we describe female mate avoidance behaviours in the European common frog. We observed three female avoidance behaviours, namely 'rotation', 'release call(s)' and tonic immobility (death feigning). These behaviours were significantly associated with smaller female body size, and smaller females were more successful in escaping amplexus. Tonic immobility as a tactic to avoid mating or male harassment has only been observed in a handful of species and only in one other amphibian. Our observations show that females in explosive breeding frogs may not be as passive and helpless as previously thought.

Observations on neurophysiological pattern and behavioural traits as death-feigning mechanism in Eucryptorrhynchus scrobiculatus (Coleoptera: Curculionidae).

In adaptation to surrounding environmental stimuli, most insects exhibit defense behaviour (death feigning) to improve survival rates in the wild. However, the underlying mechanism of death feigning remains largely unknown. Here, we tested the neurophysiological pattern and behavioural traits of the death-feigning mechanism in the forestry pest Eucryptorrhynchus scrobiculatus. Using neuroanatomy, LC-MS/MS target metabolomics detection technology and qRT-PCR, we investigated the effects of neurochemicals and metabolic pathways in experimental weevils. Excision and drug tests were conducted to verify the key regulatory body parts involved in regulating the central nervous system in death feigning. Our results reconstructed the death-feigning mechanism of E. scrobiculatus: when the effective stimuli point of arousal weevils received mechanical stimulation, the thoracoabdominal ganglion transmitted signals into the brain through the ventral nerve cord, and then the brain regulated dopamine (DA) and serotonin (5-HT) metabolic pathways, reducing the expression of dopamine (dar2) and octopamine (oar1, oab2) receptor genes, finally inducing death feigning. Our study suggests that the variation of neurotransmitters in the brain is an important indicator of the physiological response of death feigning, and the results provide ecological and theoretical information for future investigations to reveal key behaviour and target genes for pest control.

Aggregation pheromone interrupts death feigning in the red flour beetle Tribolium castaneum

AbstractDeath feigning is a behavior in which a prey is rendered motionless due to stimulation or threat by a predator. This anti-predator defense mechanism has been observed across a wide range of animal taxa and is considered adaptive. However, long durations of death feigning can decrease opportunities for feeding and reproduction, and therefore is a fitness cost as compared to environments without predators. Because death feigning is thought to be affected by the balance between survival and other fitness costs, selection pressure may drive individuals who are capable of plastic changes in the intensity of death feigning. Pheromones, which are important semiochemicals that affect foraging and reproductive success, may be one of the factors influencing the intensity of death-feigning behavior. In this study, we investigated the effect of an aggregation pheromone on the death-feigning behavior of the red flour beetle Tribolium castaneum. We found that beetles exposed to the pheromone showed a significantly shorter duration of death feigning than beetles that were not exposed to the pheromone. Therefore, our results suggest that an aggregation pheromone can plasticly alter the death-feigning behavior in T. castaneum.

Xylazine Test Strips for Drug Checking

Why is this an issue?&#x0D; &#x0D; The opioid crisis is an ongoing public health concern in Canada. In 2022, a total of 7,328 apparent opioid toxicity deaths were reported, which is an average of 20 deaths per day.&#x0D; Xylazine, referred to as tranq, is an animal tranquilizer that has appeared as an adulterant in the unregulated drug supply (particularly in opioids) and is contributing to increasing numbers of drug poisoning (overdose) events and deaths.&#x0D; There is no approved drug for humans for reversing the effects of xylazine, so detection is critical.&#x0D; &#x0D; What is the technology?&#x0D; &#x0D; The Rapid Response Xylazine Test Strip by BTNX (Pickering, Ontario) is a rapid test for the detection of xylazine that can be used for drug checking in an unregulated drug supply.&#x0D; &#x0D; What is the potential impact?&#x0D; &#x0D; Xylazine can have harmful effects, such as severe skin lesions, central nervous system depression, cardiovascular effects, and death.&#x0D; The detection of xylazine using a test strip could alter consumption behaviours, such as avoiding the use of contaminated drugs, reducing the quantity consumed, injecting more slowly, or choosing to use at a supervised consumption site.&#x0D; &#x0D; What else do we need to know?&#x0D; &#x0D; The strips are currently available in Canada for $349.00 for a box of 100 or $3.49 per strip.&#x0D; Although these strips are good at checking for xylazine, they are not designed to anticipate and test for the next adulterant to enter the unregulated drug supply which could be equally or even more dangerous. Therefore, these strips would be useful as part of a robust harm reduction strategy.&#x0D;

Impacts of mycotoxin on cultured fish

Mycotoxins are secondary metabolites produced by filamentous fungi that could cause toxic responses when ingested by animals. The extent of production varies with geographic location, feed storage practices and processing methods. In the tropics, improper bagging, transport, storage and use of feeds with inferior quality of ingredients are ways in which mycotoxin is produced and is a great challenge that threatens life of culture fish. Mycotoxins in feeds are a problem of significant concern as farmers are taking steps to overcome the challenge of feed supply. The effects result in teratogenic, carcinogenic, oestrogenic or immune-suppressive effects, poor growth, low apparent digestibility, physiological disorders, histological change and death. The expression of mycotoxin impacts is influenced by factors such as age, nutrition, sex, species and the possibility of concurrent exposure to other toxins. The main target organ in animals is the liver; therefore, mycotoxin disease is primarily hepatic. Conditions increasing the likelihood of mycotoxin impacts in aquatic organisms include limited feed availability, environmental conditions that favour mould growth on feedstuffs, and lack of regulatory systems for aflatoxin monitoring and control. Mycotoxin's effect on these organisms is not only on health problems in exposed fish but also represents a high risk to consumers through residues in fish musculature. Therefore, control and prevention measures are needed to sustain the aquatic resources. However, several effective ways to prevent and control hazardous fungi and their dangerous mycotoxins have been presented.

Sex and strain-specific spectral attraction of Tribolium castaneum (Coleoptera: Tenebrionidae): behavioral studies

We examined the attraction of adults to six LEDs in the red flour beetles, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), which is widespread as a stored grain insect. In the experiment, bluish green and green were more attractive than the two UVs, blue, and red LEDs only in females. On the other hand, no difference was found in attraction among the six LEDs in males. Next, we investigated the relationship between light intensity and attractiveness. No sexual difference in attractiveness in different light intensities was found, but the strongest light intensity was more attractive than other light intensities. Finally, we investigated the relationship between light attraction and strains artificially selected for the duration of death feigning. Short-strain beetles were more attracted to UV lights than long-strain beetles.

Evaluation of acute oral toxicity, anti-diabetic and antioxidant effects of Aloe vera flowers extract.

Aloe vera (L.) Burm.f. is widely used in various traditional systems of medicine worldwide. Since over 5000 years ago, several cultures have used A. vera extract medicinally for conditions ranging from diabetes to eczema. It has been shown to reduce the symptoms of diabetes by enhancing insulin secretion and protecting pancreatic islets. This research study aimed to investigate the in-vitro antioxidant effect, the acute oral toxicity, and the possible pharmacological in-vivo anti-diabetic activity with histological examination of the pancreas of the standardized deep red A. vera flowers methanolic extracts (AVFME). The liquid-liquid extraction procedure and TLC technique were used to investigate chemical composition. Total phenolics and flavonoids in AVFME were quantified by Folin-Ciocalteu and AlCl3 colorimetric methods, respectively. The present study involved evaluating the in-vitro antioxidant effect of AVFME using ascorbic acid as the reference standard, an acute oral toxicity study by using thirty-six albino rats and different concentrations of AVFME (200mg/kg, 2, 4, 8 and 10g/kg b.w.). Furthermore, the in-vivo anti-diabetic study was performed on alloxan-induced diabetes in rats (120mg/kg, I.P.) and two doses of AVFME (200 and 500mg/kg b.w., orally) were used as compared to glibenclamide (5mg/kg, orally) as a standard hypoglycemic sulfonylurea medication. A histological examination of the pancreas was performed. AVFME resulted in the highest phenolic content of 150.44±4.62mg gallic acid equivalent per gram (GAE/g) along with flavonoid content of 70.38±0.97mg of quercetin equivalent per gram (QE/g). An in-vitro study revealed that the antioxidant effect of AVFME was strong as ascorbic acid. The results of the in-vivo studies showed that the AVFME didn't cause any apparent toxicity signs or death in all groups at different doses which proves the safety of this extract with a wide therapeutic index. The antidiabetic activity of AVFME demonstrated a considerable drop in blood glucose levels as glibenclamide, without severe hypoglycemia or significant weight gain which is considered an advantage of AVFME over glibenclamide use. The histopathological study of pancreatic tissues confirmed the protective effect of AVFME on the pancreatic beta-cells. The extract is proposed to have antidiabetic activity through inhibition of α-amylase, α-glucosidase, and dipeptidyl peptidase IV (DPP-IV). Molecular docking studies were conducted to understand possible molecular interactions with these enzymes. AVFME represents a promising alternative source of active constituents against diabetes mellitus (DM) based on its oral safety, antioxidant, anti-hyperglycemic activities, and pancreatic protective effects. These data revealed the antihyperglycemic activity of AVFME is mediated by pancreatic protective effects while significantly enhancing insulin secretion through increasing functioning beta cells. This suggests that AVFME has the potential as a novel antidiabetic therapy or a dietary supplement for the treatment of type 2 diabetes (T2DM).