I am a postdoc with a background in Ecology, Mycology and Entomology. Currently, I am investigating the importance of biological rhythms for the survival and transmission of malaria parasites.
Given the high prevalence of biological rhythms in the natural world (spanning multiple Kingdoms), they must play an important role in an individual's fitness. To demonstrate this, I am exploring the fitness benefit of circadian rhythms to malaria parasites (Plasmodium) and its interactions with rhythms in the mosquito vector (Anopheles spp) and vertebrate hosts.
Part of my research involves asking: what are the consequences for parasite when their rhythms are perturbed? In malaria parasites I mismatch parasite rhythms with that of their rodent host. More recently, I have begun examining to mosquitoes of disrupting their feeding rhythms and asking what impact this may have for malaria transmission.
Phd by Research Publications (2022).
My thesis was awarded based on the culmination of ten years work, compiling 6 first author papers with a critical summary:
The evolutionary ecology of biological rhythms in malaria parasites (Download pdf)
Publications
Oke, C. E., O'Donnell, A. J., Schneider, P., & Reece, S. E. (2024). Plasticity in malaria parasite development: mosquito resources influence vector-to-host transmission potential. Frontiers in Malaria, 2, 1481816. https://doi.org/10.3389/fmala.2024.1481816
Parasites rely on their hosts for all their nutrition however mosquitoes in the field exhibit diversity in the amount of food they require. In this paper we ask how variation in the amount of sugar and blood provided to malaria-infected mosquitoes affects the potential for parasites to transmit from vector to host. We find that parasites in well resourced mosquitoes are bigger, faster and are more numerous. Our results also suggest that resource availability affects the ability of parasites to migrate from the midgut to salivary glands for transmission.
Holland, J. G., Prior, K. F., O’Donnell, A. J., & Reece, S. E. (2024). Testing the evolutionary drivers of malaria parasite rhythms and their consequences for host–parasite interactions. Evolutionary Applications, 17, e13752. https://doi.org/10.1111/eva.13752
We perturb several rhythms in the hosts of malaria parasites to investigate why parasites align their rhythmic replication to the host's feeding-fasting rhythm. We manipulated host rhythms governed by light, food or both, and assessed the fitness implications for par- asites to test which host rhythms represent ultimate drivers of the parasite's rhythm. We found that the host's light-driven rhythms did not affect parasite fitness but aligning with the timing of feeding-fasting rhythms may be beneficial for the parasite when the host possess a functional canonical circadian clock. Our results also suggest cue(s) from host food act as a proxy rather than being a key selective driver of the parasite's rhythm.
Westwood, M. L., Geissmann, Q., O’Donnell, A. J., Rayner, J., Schneider, W., Zuk, M., Bailey, N. W. and Reece, S. E. (2024). Machine learning reveals singing rhythms of male Pacific field crickets are clock controlled. Behavioral Ecology, 35(1), p.arad098. https://doi.org/10.1093/beheco/arad098
Evidence from field work suggests that male Pacific field crickets are changing the time of day they sing potentially as an anti-parasitoid strategy. We demonstrate that male calling behaviour meets all criteria for being an endogenous trait controlled by the circadian clock and thus could be a target for natural selection imposed by the parasitoid.
O’Donnell, A. J., Greischar, M. A., & Reece, S. E. (2021). Mistimed malaria parasites re‐synchronise with host feeding‐fasting rhythms by shortening the duration of intra‐erythrocytic development. Parasite Immunology, e12898. https://doi.org/10.1111/pim.12898
Reveals that synchrony and timing of the IDC follows rhythms associated with host feeding/fasting that are independent of the host’s canonical circadian clock (including the light-entrained oscillator in the brain and the transcription-translation-feedback-loop within all cells). Further, IDC synchrony dampens in the absence of feeding/fasting rhythms. Subsequently verified by others.
O’Donnell, A. J., Reece, S. E. (2021) Ecology of asynchronous asexual replication: the intraerythrocytic development cycle of Plasmodium berghei is resistant to host rhythms. Malaria Journal 20, 105 . https://doi.org/10.1186/s12936-021-03643-z
Demonstrates that the various peturbations that normally lead to synchronisation of parasite cycles in P. chabaudi do not have the same effect on a related species, P. berghei.
Davidson, M. S., Yahiya, S., Chmielewski, J., O’Donnell, A. J., Gurung, P., Jeninga, M., Prommana, P., Andrew, D., Petter, M, Uthaipibull, C., Boyle, M., Ashdown, G. W., Dvorin, J. D., Reece, S. E., Wilson, D. W., Ando, D. M., Dimon, M. & Baum, J. (2021). Automated detection and staging of malaria parasites from cytological smears using convolutional neural networks. medRxiv. https://doi.org/10.1101/2021.01.26.21250284
Describes a novel machine learning method for identifying and staging parasites from microscopy images.
Prior, K. F., Middleton, B., Owolabi, A. T., Westwood, M. L., Holland, J., O'Donnell, A. J., Skene, D. J. & Reece, S. E. (2021). An essential amino acid synchronises malaria parasite development with daily host rhythms. bioRxiv. https://doi.org/10.1101/2020.08.24.264689
Screens for rhythmic metabolites in the blood of infected mice whose timing matches that of both host feeding/fasting and the IDC schedule (across perturbations of host and parasite rhythms). Finds a single candidate, isoleucine, and in vitro tests reveal isoleucine fulfils all criteria of a time-cue.
O'Donnell A. J., Prior K. F. and Reece S. E. (2020). Host circadian clocks do not set the schedule for the within-host replication of malaria parasites. Proceedings of the Royal Society B 287: 20200347. http://dx.doi.org/10.1098/rspb.2020.0347
Demonstrate that rhythms in the development cycle of malaria are linked to feeding associated rhythms in the mouse host and not the hosts core-TTFL clock.
Subudhi A. K., O’Donnell A. J., Ramaprasad A., Abkallo H. M., Kaushik A., Ansari H. R., Abdel-Haleem A. M., Rached F. B., Kaneko O., Culleton R., Reece S. E. & Pain, A. (2020). Malaria parasites regulate intra-erythrocytic development duration via serpentine receptor 10 to coordinate with host rhythms. Nature Communications 11(2763). https://doi.org/10.1038/s41467-020-16593-y
Demonstrates that: 57% of P. chabaudi’s and 6% of P. falciparum’s genes are expressed with 24hr rhythms; rhythmicity is lost in half of P. chabaudi’s genes when misaligned to host rhythms; and SR10 determines the IDC duration. Provides insight into why misalignment reduces fitness and reveals parasite control of the IDC schedule.
Westwood M. L., O’Donnell A. J., Schneider P., Albery G. F., Prior K. F., & Reece S. E. (2020). Testing possible causes of gametocyte reduction in temporally out-of-synch malaria infections. Malaria Journal, 19(1):1-10. https://doi.org/10.1186/s12936-020-3107-1
Tests whether the observed 50% reduction in gametocytes in temporally mismatched parasites can be explained by a reduction in conversion rate or increased cleareance by the hosts immune responses
Birget P. L. G., Schneider P., O’Donnell A. J., & Reece S. E. (2019). Adaptive phenotypic plasticity in malaria parasites is not constrained by previous responses to environmental change. Evolution, Medicine, and Public Health, eoz028. https://doi.org/10.1093/emph/eoz028
Malaria parasites have evolved flexible strategies to cope with the changing conditions they experience during infections. We show that using such flexible strategies does not impact upon the parasites’ ability to grow (resulting in disease symptoms) or transmit (spreading the disease).
Prior K. F., O’Donnell A. J., Rund S. S., Savill N. J., van der Veen D. R., & Reece S. E. (2019). Host circadian rhythms are disrupted during malaria infection in parasite genotype-specific manners. Scientific Reports, 9:10905. https://doi.org/10.1038/s41598-019-47191-8
Characterises differences infection dynamics in three parasite genotypes in response to timing disruption and shows that the disruption is a genetically variable virulence trait
O’Donnell A. J., Rund S. S. C., Reece S. E. (2019). Time-of-day of blood-feeding: effects on mosquito life history and malaria transmission. Parasites & vectors, 12(1):301. https://doi.org/10.1186/s13071-019-3513-9
With reports of mosquitoes biting earlier in the day as a strategy to avoid insecticide treated bed nets, this paper explores the consequence of altered biting time on mosquito life history and parasite trasmission
Westwood M. L., O’Donnell A. J., de Bekker C., Lively C. M., Zuk M., & Reece, S. E. (2019). The evolutionary ecology of circadian rhythms in infection.Nature ecology & evolution, 18(1). https://doi.org/10.1038/s41559-019-0831-4
Explores how hosts use rhythms to defend against infection, why parasites have rhythms and whether parasites can manipulate host clocks to their own ends.
Lippens C., Guivier E., Reece S. E., O’Donnell A. J., Cornet S., Faivre B., & Sorci G. (2018). Early Plasmodium‐induced inflammation does not accelerate aging in mice. Evolutionary Applications, 12(2):314-23.https://doi.org/10.1111/eva.12718
Tests the hypothesis that early activation of the inflammatory response confers protection against infection, it results in reduced reproductive output at old age and shortened longevity.
Schneider P., Rund S. S. C., Smith N. L., Prior K. F., O'Donnell A. J., & Reece S. E. (2018). Adaptive periodicity in the infectivity of malaria gametocytes to mosquitoes. Proceedings of the Royal Society B, 285(1888):20181876. https://doi.org/10.1098/rspb.2018.1876
Reveals gametocytes are twice as infective at night to mosquitoes and that vector rhythms also affect transmission. Answers a longstanding question posed by Hawking in the 1960’s but plagued with poor study design until now. Subsequently verified by others
Prior K. F., van der Veen D. R., O'Donnell A. J., Cumnock K., Schneider D., Pain A., Subudhi A., Ramaprasad A., Rund S. S. C., Savill N. J., & Reece S. E. (2018) Timing of host feeding drives rhythms in parasite replication. PLOS Pathogens, 14(2):e1006900. https://doi.org/10.1371/journal.ppat.1006900
Reveals that the hosts' peripheral rhythms (associated wicth the timing of feeding and metabolism), but not rhythms driven by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms.
Birget P. L., Repton C., O'Donnell A. J., Schneider P., & Reece S. E. (2017) Phenotypic plasticity in reproductive effort: malaria parasites respond to resource availability Proceedings of the Royal Society B, 284(1860):20171229. https://doi.org/10.1098/rspb.2017.1229
Reveals that the malaria parasite Plasmodium chabaudi responds to host anaemia by increasing investment in transmission stages because, counterintuitively, host aneamia represents a better environment for parasite replication. Furthermore, evolutionary potential in form of genetic variation exists in the extent that parasite strains respond to changes in red blood cell resources.
Rund, S.S.C.; O’Donnell, A.J.; Gentile, J.E.; Reece, S.E. (2016) Daily Rhythms in Mosquitoes and Their Consequences for Malaria Transmission. Insects, 7, 14.
Outlines new hypotheses for how daily rhythms in mosquitoes affects their capacity to transmit malaria parasites.
O’Donnell A.J., Mideo N. and Reece S.E. (2013) Disrupting rhythms in Plasmodium chabaudi: costs accrue quickly and independently of how infections are initiated. Malaria Journal, 12:372. doi:10.1186/1475-2875-12-372.
Asks whether parasites matched to the hosts circadian rhythm are better able to establish infections than mismatched parasites
A correction has been published for this article: O’Donnell A.J., Mideo N. and Reece S.E. (2014) Correction: Disrupting rhythms in Plasmodium chabaudi: costs accrue quickly and independently of how infections are initiated. Malaria Journal, 13:503. doi:10.1186/1475-2875-13-503.
Schneider P., Bell A.S., Sim D.G., O'Donnell A.J., Blanford S., Paaijmans K.P., Read A.F. and Reece S.E. (2012) Virulence, drug sensitivity and transmission success in the rodent malaria, Plasmodium chabaudi. Proceedings of the Royal Society of London Series B. doi:10.1098/rspb.2012.1792.
Drug treatment selects for the evolution of more harmful parasite strains.
Staszewski V., *Reece S.E., O'Donnell A.J. and *Cunningham E.J.A. (2012) Drug treatment of malaria infections can reduce levels of protection transferred to offspring via maternal immunity. Proceedings of the Royal Society of London, Series B online February 22. doi:10.1098/rspb.2011.156. *equal contributions
Shows that giving antimalarial drugs to pregnant mice can make their offspring more vulnerable to malaria than if mothers are untreated.
O'Donnell A.J., Schneider P., McWatters H.G. and Reece S.E. (2011) The fitness costs of disrupting circadian rhythms in malaria parasites. Proceedings of the Royal Society London B. doi:10.1098/rspb.2010.2457
Research highlight microbiology (Nature) and Faculty of 1000 evaluation (recommended)
Modernised the study of ‘periodicity’ in malaria infection and provided a rare demonstration of the fitness benefits of rhythmic behaviour. Specifically, reveals that parasite fitness (in host survival and transmission potential) is enhanced when Plasmodium’s IDC rhythm is in synchrony with the host’s circadian rhythms.
Media Attention:
O'Donnell A.J., Schneider P., McWatters H.G. and Reece S.E. (2011) The fitness costs of disrupting circadian rhythms in malaria parasites. Proceedings of the Royal Society London B. doi:10.1098/rspb.2010.2457
Faculty of 1000 Post Publication Peer Review (Patrick Duffy) 8 Feb 2011
Research highlight Nature 13 Jan 2011 The Scotsman Jan 7 2011
TIME Newsfeed Jan 7 2011
Metro Jan 7 2011
Herald Jan 7 2011
Yorkshire Post Jan 7 2011
The Times of India Jan 7 2011
Sydsvenskan (Sweden) Jan 7 2011
The Press Association Jan 6 2011
BBC News Jan 6 2011
The Scientist Jan 5 2011
Science.ORF.AT (Austria) Jan 5 2011
Handelsblatt (Germany) Jan 5 2011
Speigel Online (Germany) Jan 5 2011
Sueddeutsche (Germany) Jan 5 2011
Spektrumdirekt (German) Jan 5 2011
Dnews (Germany) Jan 5 2011
Diario Digital Nuestro País (Costa Rica) Jan 6 2011
Ask Science Dude Podcast (mp3)
EuSci Podcast (itunes)
Positions
2008 - Present
Currently employed as a Research Assistant assisting with research into the evolutionary ecology of Malaria.
2007 - 2008
Research technician with Landcare Research involved with a bioprospecting project, collecting and extracting fungal cultures from native forests as well as a large scale fungal population experiment.
2006 - 2007
Ecologist with Oratia Native Plants assisting with a Volcanic cones revegetation project using native grasses.
2006 - 2006
Junior Ecologist for Aranovus Limited involved working on wetland and forest restoration in Auckland..
2003 - 2005
M.Sc. Thesis, Major in Biological Sciences (Ecology): School of Biological Sciences, University of Auckland, New Zealand. The impacts of habitat disturbance on invertebrate and lizard fauna within an agricultural setting
2000 - 2002
B.Sc. Major in Biological Science: School of Biological Sciences, University of Auckland, New Zealand