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Models for human porphyrias: Have animals in the wild been overlooked?

Humans accumulate porphyrins in the body mostly during the course of porphyrias, diseases caused by defects in the enzymes of the heme biosynthesis pathway and that produce acute attacks, skin lesions and liver cancer. In contrast, some wild mammals and birds are adapted to accumulate porphyrins without injurious consequences. This study proposes to view such physiological adaptations as potential solutions to human porphyrias, and suggest certain wild animals as models. Given the enzymatic activity and/or the patterns of porphyrin excretion and accumulation, the fox squirrel, the great bustard and the Eurasian eagle owl may constitute overlooked models for different porphyrias. The Harderian gland of rodents, where large amounts of porphyrins are synthesized, presents an underexplored potential for understanding the carcinogenic/toxic effect of porphyrin accumulation. Investigating how these animals avoid porphyrin pathogenicity may complement the use of laboratory models for porphyrias and provide new insights into the treatment of these disorders. informacion[at] De Oliveira Neves & Galvan (2020) Models for human porphyrias: Have animals in the wild been overlooked? BioEssays. DOI 10.1002/bies.202000155
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Mosquitoes are attracted to Plasmodium-infected birds

Mosquitoes are attracted to Plasmodium-infected birds

Parasites can manipulate their hosts to increase their transmission success. Avian malaria parasites (Plasmodium) are thought to alter the cues such as host odour, used by host-seeking mosquitoes. Bird odour is affected by secretions from the uropygial gland and may play a role in modulating vector-host interactions. The hypothesis tested was  that mosquitoes are more attracted to the uropygial secretions and/or whole-body odour (headspace) of Plasmodium-infected house sparrows (Passer domesticus) than to those of uninfected birds. The attraction of nulliparous (e.g. uninfected mosquitoes without previous access to blood) Culex pipiens females towards these stimuli was tested in a dual-choice olfactometer. Gas Chromatography-Mass Spectrometry (GC–MS) analyses were used to assess whether Plasmodium infection is associated with differences in the chemical composition of uropygial secretions. Mosquitoes were more attracted to the odours of infected than uninfected birds, regardless of sex. However, the significant interaction between infection status and the stimuli (uropygial secretion or headspace) showed that mosquitoes were more attracted to the headspace of infected birds; no differences were found in the case of uropygial secretions. The compounds in the volatile lipophilic fraction of the uropygial secretion did not differ between infected and uninfected birds. These results support the host manipulation hypothesis since avian Plasmodium parasites may be capable of altering their host's body odour, thereby making infected individuals more attractive to mosquitoes. informacion[at] Díez-Fernández et al (2020) Mosquitoes are attracted by the odour of Plasmodium-infected birds. International J Parasitology. DOI 10.1016/j.ijpara.2020.03.013