ABSTRACT
Introduction and importance: SARS-CoV-2 infection has been linked to the de novo diagnosis of various autoimmune conditions as well as flares in pre-existing disease. With such high prevalence of SARS-CoV-2 in the community, it is important to consider rare manifestations of autoimmune conditions when patients present with severe symptoms. Multi-specialty care is required to ensure optimal outcomes and prompt diagnosis. Case presentation: A 28-year-old male presented to our tertiary referral centre with progressive debilitating polyarthritis, a purpuric rash on both flanks and aphthous ulcers 6 weeks after infection with SARS-CoV-2. On the second day of admission, he developed severe gastrointestinal haemorrhage requiring multiple blood transfusions. Attempted angioembolisation failed to identify a site of active haemorrhage. On failing trial of conservative management, the decision was made to perform an exploratory laparotomy. The small bowel was found to have an extensive vasculitis requiring resection to control haemorrhage. Autoimmune serology revealed c-ANCA positivity with anti-PR3 antibodies. Clinical discussion: Patients presenting with acute vasculitic pathologies related to SARS-CoV-2 have the potential to rapidly progress to severe life-threatening gastrointestinal haemorrhage. Prompt surgical management is appropriate in selected cases. Conclusion: In the current era of COVID-19, the differential diagnosis of SARS-CoV-2 induced ANCA vasculitis must be considered for such cases with gastrointestinal haemorrhage. Compilation of similar cases and further studies are required to determine an optimal management pathway for these patients.
ABSTRACT
Multiple mating in female animals is something of a paradox because it can either be risky (e.g., higher probability of disease transmission, social costs) or provide substantial fitness benefits (e.g., genetic bet hedging whereby the likelihood of reproductive failure is lowered). The genetic relatedness of parental units, particularly in lizards, has rarely been studied in the wild. Here, we examined levels of multiple paternity in Australia's largest agamid lizard, the eastern water dragon (Intellagama lesueurii), and determined whether male reproductive success is best explained by its heterozygosity coefficient or the extent to which it is related to the mother. Female polyandry was the norm: 2/22 clutches (9.2%) were sired by three or more fathers, 17/22 (77.2%) were sired by two fathers, and only 3/22 (13.6%) clutches were sired by one father. Moreover, we reconstructed the paternal genotypes for 18 known mother-offspring clutches and found no evidence that females were favoring less related males or that less related males had higher fitness. However, males with greater heterozygosity sired more offspring. While the postcopulatory mechanisms underlying this pattern are not understood, female water dragons likely represent another example of reproduction through cryptic means (sperm selection/sperm competition) in a lizard, and through which they may ameliorate the effects of male-driven precopulatory sexual selection.
ABSTRACT
Understanding individual differences in cognitive performance is a major challenge to animal behaviour and cognition studies. We used the Eastern water skink (Eulamprus quoyii) to examine associations between exploration, boldness and individual variability in spatial learning, a dimension of lizard cognition with important bearing on fitness. We show that males perform better than females in a biologically relevant spatial learning task. This is the first evidence for sex differences in learning in a reptile, and we argue that it is probably owing to sex-specific selective pressures that may be widespread in lizards. Across the sexes, we found a clear association between boldness after a simulated predatory attack and the probability of learning the spatial task. In contrast to previous studies, we found a nonlinear association between boldness and learning: both 'bold' and 'shy' behavioural types were more successful learners than intermediate males. Our results do not fit with recent predictions suggesting that individual differences in learning may be linked with behavioural types via high-low-risk/reward trade-offs. We suggest the possibility that differences in spatial cognitive performance may arise in lizards as a consequence of the distinct environmental variability and complexity experienced by individuals as a result of their sex and social tactics.
