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Zika Virus May Now Be Tied to Another Brain Disease

The Zika virus may be associated with an autoimmune disorder that attacks the brain’s myelin similar to multiple sclerosis, according to a small study that was presented at the American Academy of Neurology’s 68th Annual Meeting in Vancouver, Canada, April 15 to 21, 2016.

“Though our study is small, it may provide evidence that in this case the virus has different effects on the brain than those identified in current studies,” said study author Maria Lucia Brito Ferreira, MD, with Restoration Hospital in Recife, Brazil. “Much more research will need to be done to explore whether there is a causal link between Zika and these brain problems.”

For the study, researchers followed people who came to the hospital in Recife from December 2014 to June 2015 with symptoms compatible with arboviruses, the family of viruses that includes Zika, dengue and chikungunya. Six people then developed neurologic symptoms that were consistent with autoimmune disorders and underwent exams and blood tests. The authors saw 151 cases with neurological manifestations during a period of December 2014 to December 2015. All of the people came to the hospital with fever followed by a rash. Some also had severe itching, muscle and joint pain and red eyes. The neurologic symptoms started right away for some people and up to 15 days later for others.

Of the six people who had neurologic problems, two of the people developed acute disseminated encephalomyelitis (ADEM), an attack of swelling of the brain and spinal cord that attacks the myelin, which is the coating around nerve fibers. In both cases, brain scans showed signs of damage to the brain’s white matter. Unlike MS, acute disseminated encephalomyelitis usually consists of a single, attack that most people recover from within six months. In some cases, the disease can reoccur. Four of the people developed Guillain-Barré syndrome (GBS), a syndrome that involves myelin of the peripheral nervous system and has a previously reported association with the Zika virus.

When they were discharged from the hospital, five of the six people still had problems with motor functioning. One person had vision problems and one had problems with memory and thinking skills.

Tests showed that the participants all had Zika virus. Tests for dengue and chikungunya were negative. “

This doesn’t mean that all people infected with Zika will experience these brain problems. Of those who have nervous system problems, most do not have brain symptoms,” said Ferreira. “However, our study may shed light on possible lingering effects the virus may be associated with in the brain.”

“At present, it does not seem that ADEM cases are occurring at a similarly high incidence as the GBS cases, but these findings from Brazil suggest that clinicians should be vigilant for the possible occurrence of ADEM and other immune-mediated illnesses of the central nervous system,” said James Sejvar, MD, with the Centers for Disease Control and Prevention in Atlanta and member of the American Academy of Neurology. “Of course, the remaining question is ‘why’–why does Zika virus appear to have this strong association with GBS and potentially other immune/inflammatory diseases of the nervous system? Hopefully, ongoing investigations of Zika virus and immune-mediated neurologic disease will shed additional light on this important question.”

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via :))) by Inna Dubrovskaya / 500px Autumn Leaves

Katsushika Hokusai (葛飾北斎?, outubro ou novembro de 1760 – 18 de abril de 1849) foi um artista japonês, pintor de estilo ukiyo-e e gravurista do período Edo. Em sua época, era um dos principais especialistas em pintura chinesa do Japão.[1] Nascido em Edo (atual Tóquio), Hokusai é melhor conhecido como autor da série de xilogravuras Trinta e seis vistas do monte Fuji (富嶽三十六景, Fugaku Sanjūroku-kei?, c. 1831) que inclui sua pintura icônica e internacionalmente conhecida, A Grande Onda de Kanagawa, criada durante a década de 1820.

Katsushika Hokusai

yuri mizutani Original_2015

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Why are some insects so shiny and iridescent?

First here’s a post I answered on HOW insects form shiny or iridescent exoskeletons. It’s always good to know the answer to how because it can give context to the why. So why are some insects iridescent or shiny? 

This can be split into two main categories; communicative functions and non-communicative.  

COMMUNICATION

1. Mate Selection 

While insects tend to use chemical communication more as a means of attracting potential mates colouration can however play a significant role in mate selection in a number of ways. 

Honest signalling - in which the colouration reveals the quality of the individual as these colourations are costly to produce. Therefore only individuals that are high-quality are able to afford the cost of producing these signals (in this case the iridescence or shiny colouration)

Example: 

A study (Fitzstephens & Getty, 2000) found that male Calopteryx maculata (Black-winged damselfly) with higher fat stores had a much bluer iridescent colouration compared to males on low fat diets.

Amplifier traits - iridescent / shiny colours may be used to amplify the differences in the signals of quality (however no studies have directly focused if this is a function of iridescence)

Sensory drives - iridescent colouration was favoured due to being more effective in signalling in certain ecological environments 

Receiver Bias -  females (or in rare cases the males or hermaphrodites) as the receivers may have favoured certain iridescent colouration due to being better received by their sensory system therefore resulting in the evolution of this colouration

2. Species Recognition

Man species use iridescent / shiny colouration in order to identify members of their own species! As simple as that! 

Example: 

Colias eurytheme (orange sulfur butterfly) use UV iridescence to communication with conspecifics

3.Agonistic interactions

Iridescense / shiny colouration may be used in intrasexual encounters; mostly male-male agonistic encounters and can be used as a territorial signal.

4.flocking behaviour

Can help insects that school together facilitate their orientation or direction within their schools / flocks. This is seen in many aquatic species of fish and even squid. 

5.  Predation avoidance 

Iridescense / shiny colouration can be used to order to actually avoid predation! Although at first glance you’d assume this would make them more visible, this isn’t always the case. 

Mimicry / camouflage - insects can avoid predation by mimicking objects, leaves, raindrops, other harmful species or even by blending into the background 

Examples: 

A number of iridescent jumping spider species (Salticidae);  such as Brettus adonis in this study (Jackson & Hallas 1986) were found to mimic raindrops to avoid predation   

The iridescent green leaf beetles such as the  (Dogbane Leaf Beetle, Chrysochus auratus) similarity use their iridescence colouration to mimic dew on leaves.

Species like tiger beetles ( Cicindelinae) even use their iridescence to create an unsaturated appearance that allow them to blend into their envrionment (Schultz 1986, 2001)

Warning colouration - insects may use their colouration to communicate their toxicity or unpalatability serving as aposematic warning.

Example: 

Panamanian tortoise beetle (Charidotella egregia) that change from gold to red when disturbed by predators(Vigneron et al. 2007).

Startle displays - some species will use their iridescence colouration to create a flash that may startle potential predators long enough for them to escape due to the way in which the iridescence reflects light.

Example:

The tiger beeltes again! Some of them have bright colouration like below that they use as startle defenses against predators (Sargent 1990). 

NON-COMMUNICATION

1. Thermoregulation

There’s much debate over whether Iridescense / shiny colouration has any function in either heat absorption or dispersion. 

Some found evidence that the structures used to created iridescense / shiny colouration acted as heat collectors, like in the wings of butterflies ( Miaoulis & Heilman 1998). However other’s have found no evidence of thermoregulation in tiger beetles Schultz & Hadley (1987). 

2.Friction reduction

iridescense structures may reduce the friction in burrowing insects  

Example: Carabid Beetles (Brachininae) (Seago et al. 2009). 

These are just some of the proposed and studied functions of iridescense and shiny colouration in insects, there are more that aren’t as well studied or understood just yet! 

More reading: 

Doucet S, Meadows M 2009, ‘Iridescence: a functional perspective’, Journal of the Royal Society Interface, vol.6, no.2, pp.115–132 

Meadows M, Butler M, Morehouse N, Taylor L, Toomey M, McGraw K, Rutowski R 2009, ‘Iridescence: views from many angles’, Journal of the Royal Society Interface, vol.6, pp.203–211

Um olhar apenas.