Model organisms are crucial for the progress of scientific research- whether it’s basic science or translational biomedical research.  I entered graduate school convinced that if I couldn’t study humans, then I’ll do mammalian research (i.e., rats or mice) because they are “more important” and potentially more informative than invertebrates like the fruit fly, Drosophila melanogaster.  Because of this, I centered three of my four first-year lab rotations solely on their mammalian organisms, and then considered if the research topics were of interest.  I reasoned that if I wanted to study neuroscience, then how informative and translational can a fly brain be?  From my introductory to biology courses, it was clear why “lower” organisms (e.g., the fly or even nematode) were incredibly useful for gene expression and regulation, but that was it… right?  The neuron types and circuit are not paralleled; so again, what could possibly be interesting to a budding neuroscientist in fly labs? It wasn’t until that fourth lab rotation (which turned out to be my eventual thesis lab) that I realized how wrong I was. Yes, the specific neuron types and their respective connections are different, but that they are more similar than distinct.  I hadn’t realized that less complex systems are also awesome in addressing larger concepts like the balance of excitation and inhibition, as well as microscopic details like the specific mechanism of neural transmission.  Thus, prioritize your research interests first, then address how that’ll be accomplished with your organism as a mere tool.

Circadian rhythm is the 24-hour physiological processes throughout a light/dark cycle. In other words, how your body responds to daylight/nighttime. It’s obvious to say that (most) people wake up in the morning feeling energized, to then feeling like napping (or taking a siesta) in the afternoon, to being awake again later in the night until you eventually fall asleep. Remarkably, this activity pattern is conserved across many species, down to rodents and even fruit flies- yes, those teeny, tiny flies feeding on your bananas at home. So, why is this even a concern? Altered activity patterns and disrupted sleep is seen in many neurological diseases and psychological disorders.  Seeing the same characteristic in different health conditions is unlikely a coincidence, suggesting your “biological clock” is somehow associated with your mental health. To further investigate what really goes on, scientists need to turn to a simple model organism for their research experiments, such as the fruit fly Drosophila melanogaster.

Here are the top five scientific articles I recently read this week relating to circadian rhythms/sleep in Drosophila:

1. Sitaraman, D., Aso, Y., Chen, N., Felix, M., Rubin, G.M., and Nitabach, M.N. 2015. Propagation of homeostatic sleep signals by segregated synaptic microcircuits of the Drosophila Mushroom Body. Current Biol 25:2915-2927.
2. Seidner, G., Robinson, J.E., Wu, M., Worden, K., Masek, P., Roberts, S.W., Keene, A.C., and Joiner, W.J. 2015. Identification of neurons with a privileged role in sleep homeostasis in Drosophila melanogaster. Current Biol 25:2928-2938.
3. Larkin, A., Chen, M., Kirazenblat, L., Reinhard, J., van Swinderen, B., and Claudianos, C. 2015. Neuroxin-1 regulates sleep and synaptic plasticity in Drosophila melanogaster. Euro J Neurosci 42:2455-2466.
4. Mazzoccoli et al., 2016. A Timeless link between circadian patterns and disease. Trends Molec Med 22(1):68-81.
5. Abruzzi, K., Chen, X., Nagoshi, E., Zadina, A., and Rosbash, M. 2015. RNA-seq profiling of small numbers of Drosophila Methods Enzymology 551:369-386.

The Zika virus (ZIKV) will manifest first as a mild headache, then a rash covering prominent areas of the body.  Usually followed by mild fever and back pain the next day, you will actually start to feel better by the end of the second day of illness.  The fever will subside and the rash will eventually go away within a couple of weeks.  There are no deaths associated with the illness.  Other than the discomfort of being ill for a couple of days, why is this a public health concern in Africa, Asia, and now Latin America?  To uncover the truth, we will have to go below the surface.

Similar to yellow fever, dengue fever, and West Nile, ZIKV is primarily transmitted as a mosquito-borne illness (via Aedes aegypti mosquitoes). Originating in the Zika Forest of Uganda, there have been cases in other African countries, such as, Tanzania, Egypt, Nigeria, and Sierra Leone, and regions of Asia, including India, Thailand, and the Philippines. It wasn’t until 2007, nearly 60-years after its discovery, that the virus was detected outside of Africa and Asia.  So how did this become a large concern in Latin America?  As most mosquito- transmitted illnesses, the answer likely lies through tourism, especially in Brazil because of the FIFA world soccer cup in 2014.

It was reported that an animal study using in mice have shown the virus is a neurotoxic. Neuronal cells were degraded and general softening of the brain was observed in these young mice.  But this conclusion was not cited and I could not identify any such research publication.  In contrary to this observation, Dr. Brain D. Foy of Colorado State University (an expert in insect-borne illnesses) states that mice, rates and other common research model organisms cannot be infected with the ZIKV, making it difficult to study the virus in traditional animal studies. So what is the evidence of the effects of Zika Virus on brain development? Two pregnant woman in Brazil were found with ZIKV in the amniotic fluid and those fetuses were born with microcephaly (a smaller head circumference). In association with the rise of ZIKV, there was also in increase in the amount of microcephaly births in the Northeast regions of Brazil. There have been more than 150 microcephaly cases in this region last year, which happens to be Brazil’s poorest region.  Because of this two isolated cases and a correlation, couples who want to start families are being told to delay their pregnancies in other countries.  Colombia, the second in highest infection rates, is recommending women delay their pregnancies for six to eight months.  However, El Salvador is advising women to delay for two years.  Despite El Salvador’s more than 5,000 cases of the Zika virus, there has not been any reports of microcephaly.

The Zika Virus, along with any other mosquito-transmitted illness, should not be taken lightly.  But the scientific evidence directly linking the virus outbreak with birth defects is simply lacking.  The only rational fear that I can see in this situation is fear for the unknown.