Venom the movie...REAL??? not clickbait almost died

The products of evolution are fascinating and complex. Life intersects in countless interlocking processes, and we find many of these to be beautiful. There are some ways of life, however, that are less photogenic, and those are the kind I want to talk in this post. Specifically, one of the reproductive strategies we find most disturbing: behavior-altering parasitism, in which the behavior of the host is altered to maximize the success of its parasite.

(like this guy)

So what does that mean? In this case, we’re not talking behavior like the usefulness of a cough for spreading germs. We’re talking a perceptive shift that changes the way that that host interacts with the world. For most of us, the most familiar example is rabies. The basic physical symptoms of the rabies virus are fever, headache, and vomiting, with partial paralysis at later stages, but behavior is also affected, causing anxiety, confused agitation, and hyperactivity. Weirdly, the infected develop a fear of water. Nocturnal animals become active during the day. Behavior becomes increasingly reckless. 

Saliva collecting in the mouth is probably the most well known symptom of rabies.

This all happens for a reason. Digging a little deeper, the direct correlation between these symptoms and transmission of the parasite is obvious. The deranged nervous behavior makes it much more likely that the infected animal will pass on the rabies to another host, while the aversion to water and drink in general keeps saliva (through which rabies is passed) collected, pooling, in the mouth. All the better to infect you with! 

The Baculoviridae family of viruses cause even grosser effects. Acting on caterpillars, they cause their hosts to gorge themselves providing nutrients for the parasite. When the virions (virus bits) are ready to leave the host, the caterpillar’s cells begin producing enzymes that “dissolve the animal into goo.” This scatters clumps of infected material that can be ingested by future hosts! (Yay recycling!) 

Another great example of parasitically altered behavior is toxoplasmosis. Rodents that consume fecal matter from infected animals become more reckless and less fearful of predators-- even, dramatically, attracted to the scent of cat urine. 

(Interestingly, mice that have been cured of toxoplasmosis remain unafraid of cats, suggesting a lasting structural change in the brain.) 

This all, of course, makes those infected mice much more likely to be eaten by a cat: the definitive host. Definitive hosts are what you might call final or “preferred” hosts, a stable environment in which the parasite can kick back, reach maturity and reproduce. 

Not only mice and cats are affected by toxoplasmosis. Considered a neglected parasitic infection in the US, it causes "mild flu-like symptoms" at worst in those humans whose immune systems are able to battle the parasite. Most immune systems are; according to the CDC, over 40 million people in the States carry the parasite, with only a tiny fraction showing symptoms. But it can cause death if your immune system is compromised by something like AIDS, and if you become infected while pregnant (or just before you get pregnant), the results for your kid could be equally serious. The effect could be as obvious as losing the baby, or symptoms (seizures, blindness, or mental disability) might only surface in that child years after birth. Some scientists think that the effect of toxoplasmosis on the general (human) population is even more staggering. One fairly prolific proponent of this is Jaroslav Flegr, a parasitologist and evolutionary biologist who has written about toxoplasmosis' influence on everything from traffic accidents to sex ratios, mental illness and human personality. Much of this writing, to summarize very simply, discusses the increased recklessness also seen in infected mice. 

This effect on the mice is called parasite-increased trophic transmission, in which the host behavior is altered to make that host more likely to be eaten by an animal at a higher trophic level (in layman’s terms, a predator), thus passing on the parasite through ingestion (in layman’s terms, eatin it). 

Behavior-altering parasitism is a wide-ranging strategy, not only exhibited by viruses like rabies and protozoa like Toxoplasma gondii, but crustaceans, insects, and parasitic worms (like leeches and tapeworms). 

(above) A horsehair worm with cricket host.
(below) A flatworm (green dude) with a snail host 

(both images from wikipedia)

It can also lead to more complex behaviors than increased recklessness. For example, the larvae of the wasp Hymenoepimecis argyraphaga are grown in Leucauge argyra spiders. Before they finish killing the host, those larvae inject the spider with a chemical that alters weaving behavior. The spider, before dying, weaves a different sort of web for the larvae to pupate in, one specifically to keep their cocoons supported and dry. These more complicated changes in behavior are what are most spectacularly cool to me. 

Another very dramatic change in behavior is caused by the Cordyceps genus of fungi. Acting on insects, it is also known as the zombie ant fungus, due to its effects on its host. Spores attach to the ant and "dig" down into its exoskeleton, where they spread out along the muscles. David Hughes (an entomologist who's studied zombie ants) describes how the fungus replaces the ant from the inside out: "We found that a high percentage of the cells in a host were fungal cells. In essence, these manipulated animals were a fungus in ants’ clothing." The results of Hughes' team's research suggest that the fungus directly manipulates the legs and mandibles of the ant, like a puppeteer, and that a "large proportion" of the fungal cells seem connected to each other in a 3D network, working collectively to control the different behaviors required from the different parts of the host's body. Infected ants are moved to ideal places for the fungus to reproduce, over time (perhaps even years) creating mass graves of strange, overgrown little corpses. Cordyceps out of control can destroy an entire colony of ants, robbing itself of its own legs, so to speak, and so there is a balance struck by the ecosystem that continues to be researched, where just enough ants are infected to help the fungus grow without stranding itself. (This is really cool- other fungi that don't harm the ants help protect their colonies from cordyceps.)

We don’t understand the mechanisms behind every kind of behavioral change yet, but one that isn't too difficult to wrap our brains around is altered neurochemical communication. So what does that mean? The brain is a physical thing. Thought and action both start as energy between neurons. If you alter the brain’s ability to communicate to the body or itself by messing with the chemicals that allow that communication, you alter the behavior. For example, the emerald cockroach wasp injects venom directly into the brain of its host, messing with the chemical balance and therefore with the brain’s responses to threatening stimuli (the escape! responses triggered by something frightening, like a wasp trying to inject stuff into your head). 

(image from wikipedia)

The host becomes usefully paralyzed without any interference on the part of the wasp to the parts of the brain responsible for movement control. Put simply: the physical ability of the host to move has not been touched. What has been changed is that the host is no longer stimulated to move-- it has no motivation, there is no incentive to react. In its way, this solution is as satisfyingly elegant as anything else evolution has produced. Energy is more efficiently spent changing the host’s innate reaction to stimuli--cutting off behavior at the source-- than simply handling the behavior once it happens. 

We often like to consider our rational thinking as something divorced from our physical selves. These parasites remind us that even the mind is just a collection of physical components-- hormones, proteins, impulses, chemicals-- that can be attacked by an outside force, just the same as our muscles and organs. Isn’t it cool?

Odd Antlers of the Animal Kingdom

Deer are undoubtedly one of the most iconic creatures of the North American animal kingdom, I mean they are the logo of four big hunting outfitting brands, two fairly large fitness brands, and three large hipster beard care brands. It is without a doubt that the iconic feature which attracts everyone to these herbivores is their elegant antlers.

While there is not a person alive who doesn't recognize these classic symbols, most people don't have the slightest clue how they work, I mean they are one of the fastest growing bones in the animal kingdom and they extend from a structure that is extremely similar to one that we as humans have, that being the skull, so how does that happen?

The answer is certainly shocking: the same genes which promote cell growth and suppress cancer cell development not only allow antlers to grow at the impressive weight they do but also maintain their shape. In deer antlers you see the same the genes which would promote tumors in humans create the rapid growth we associate with antlers but this growth is prevented from reaching a level that is unbeneficial to life for the deer by tumor suppressing genes. As Edward Davis says in the below article "...antlers [are] using essentially a controlled form of bone cancer growth".This means that during mitosis antler cells display bone cancer-like traits, growing and dividing at an abnormally fast rate. However, unlike bone cancer the growth of these cells is checked by tumor suppressor and growth genes. The tumor promoting genes are a fairly simpler concept, they simply promote cell division occurring at a higher rate but the truly amazing part of this is the genes which control cancer growth, which would be of clear interest of study to many(How Cancer Genes relate to Antler Growth ). 

Antlers are also a very promising field of study due to their extremely rare regenerative properties, sprouting in the spring and shedding in the winter, so this research could be of much interest towards therapies for bone diseases and injuries in human beings. The way scientists have attempted to deepen their understanding of this is by identifying the specific genes which lead this process. Through their research scientists at Stanford University have determined two genes which lead this process, uhrf1 and s100a10, although these two have entirely different purposes. The gene uhrf1 supports a higher rate of bone cell formation and s100a10 leads to a faster rate of mineralization. For those who are not familiar with what mineralization means in this context, more simply put, mineralization means the hardening of bone tissue, specifically due to the bone matrix becoming filled with calcium phosphate nanocrystals. This means that these two genes work together with uhrf1 growing the antlers and s100a10 shaping them into the classic shapes we associate with deer antlers.(Genetic research into Antler growth)
The problem that then arises is the same one that arises with any gene, what happens when one of these genes is turned off?

Now obviously any genes which have been turned off accidently in the DNA of a cell can be detrimental, these mutations can lead to any number of genetic disorders which can sometimes be incompatible with life. Luckily with deer antler growth the effect of either of the two pertinent genes being deactivated is not too severe as has been typically observed in the wild. As has been observed when the uhrf1 gene is non-functional deer will not have antler growth at an equitable rate and when the s100a10 gene is non-functional the rate and form of antler growth will not be suppressed and so will behave more like normal tumor cells. The s100a10 is clearly the more interesting of the two and can lead to a number of interesting yet sometimes worrying mutations.

 Image 4+5:Two deer with non-functional s100a10 genes (Link)

While these mutation are certainly interesting they are not incompatible with life for the deer and could even be beneficial to them in some scenarios. Despite these genes sometimes failing in nature, they could still prove vital to us as humans, because as mundane as deers may seem their iconic antlers might just hold the secret to preventing any other human from suffering from cancer, bone disease, or a broken bone ever again.

Zombie Deer Disease and Why We Should Fear it

This is the Zombie Apocalypse we should really be fearing because it is right at our doorstep. Now of course "Zombie Deer Disease" does not actually bring any deer back from the dead, they may just look like extras from The Walking Dead - Deer Edition. 

The proper name for this disease is Chronic Wasting Disease (CWD) and it is a progressive fatal degenerative neurological disease. Yeah, I know that all those words together are pretty freaking scary, however, you are in luck because so far it has only affected cervid populations. Cervids are the deer family, so moose, elk, mule deer, whitetail deer, reindeer, etc. and are found in all continents except Australia and Antarctica. CWD has been found in cervid populations in Canada, the United States, Norway, and South Korea (through imported deer). CWD is also a Transmissible Spongiform Encephalopathy or TSE, other TSEs are Bovine Spongiform Encephalopathy or Mad Cow disease, Scrapie, Creutzfeldt-Jakob Disease, and Fatal Familial Insomnia. TSEs are caused by abnormal proteins called prions.

A Healthy Stag (https://en.wikipedia.org/wiki/Deer#/media/File:Family_Cervidae_five_species.jpg)

Effects:
The effects of CWD are pretty scary they include holes eaten into the brain, drastic weight loss, lack of coordination and lack of fear of people (https://www.cdc.gov/prions/cwd/cwd-animals.html). Other than the obvious eating holes in the brain of the deer part there are also other reasons that this can wreak havoc on the populations. Discoordinated deer cannot protect themselves against predators like other deer can and they also do not realize that they should see humans as a threat. Also, deer with CWD by some reports die at a rate 3 times that of unaffected deer yearly. There are a few major problems that are hindering efforts to prevent CWD, first it has a really long incubation period of somewhere between 18 to 24 months and physiological symptoms do not show up until the very end. Also, it is really contagious among cervid populations and no one knows how to stop it yet. The main reason for the lack of prevention is it is not known how it is transmitted and even by depopulating any area it doesn't stop it from coming back in a totally new population later put in the area. Another reason that there is a problem is that not much can be done with the populations because no one knows how to stop it.

Deer suffering from CWD (https://www.nih.gov/news-events/news-releases/nih-study-finds-no-chronic-wasting-disease-transmissibility-macaques)

Research:

Luckily research has started to do with a few different aspects of CWD. At the University of Minnesota, they got $1.5 M to fund research into improving testing for CWD (https://www.vetmed.umn.edu/departments/veterinary-and-biomedical-sciences/spotlight/drs-pam-skinner-and-peter-larsen-aim-18m-funding-speed-chronic-wasting-disease-testing). Research was also done by the University of Wyoming to test the effects of CWD on cattle and it was found that cattle resist exposure to CWD which is good because it means that right now at least it will probably not transfer to cattle populations (http://www.uwyo.edu/uw/news/2018/05/long-term-research-shows-domestic-cattle-resist-oral-exposure-to-chronic-wasting-disease.html). The NIH also did a study to see if there was transmissibility of CWD to the primate Cynomolgus Macaque or Crab-eating Macaque for which they found no transmissibility which for humans is a good sign (https://jvi.asm.org/content/92/14/e00550-18).

Cynomolgus Macaque (https://www.nc3rs.org.uk/macaques/macaques/behaviour-and-communication/)

The Spread:
The best piece of news for humanity is actually that there is no piece of evidence for human risk yet. It has even been determined by some that most of the time a human can even eat deer meat infected with CWD. However, the threat of CWD is becoming more prevalently all the time with it now being in 21 states in the US.

Distribution of CWD in North America (https://www.usgs.gov/media/images/distribution-chronic-wasting-disease-north-america-0)

If you are interested, more information about CWD can be found at the CDC page of CWD (https://www.cdc.gov/prions/cwd/index.html) and at the CWD website (http://cwd-info.org/faq/).

Positive Change in Population Control

I am sure all of you have had that experience of wandering the neighborhood, or driving down the street, and you spot a cat. It was most likely alone, minding its own business, looking for its next meal, or just simply strolling through the town it calls its home. Have you imagined that cat yet? Now, let me ask you a question about your experience: did you notice if its ear was tipped? 

If you're someone who's never looked for a cat with a tipped ear, you're not alone! It's not something most people think about when they first see a cat, but the reason for that is because people don't know the meaning behind it. I myself never looked for that noticeable mark until the summer of 2018. This was when I started volunteering for CPAW NJ. CPAW NJ is a nonprofit organization based in Montclair. The organization's sole purpose is Trap Neuter Vaccinate and Release, or TNVR (more about this later), in the cat communities in our area. 

CPAW NJ logo from http://cpawnj.org/

Karen Shinevar, the president of this charity, gave me the opportunity to help socialize a couple kittens and adult cats that they had rescued from the street. In this adventure, I was able to interact with cats who changed my opinion of feral cats and their impact on our community. Karen was honest to me in revealing that their plan was no longer to try to get cats adopted, but rather facilitate TNVR anywhere they could spread it. 

Jack and Turner photographed by me :)
both have been luckily adopted 

 All the cats I met while working this program were absolutely delightful. I worked with Jack and Turner, two siblings who both sustained injuries to their eyes pictured above, and with Oreo, he was abused when he was younger due to him being the only black kitten to come out of his mom's litter. Since then, Oreo has been rescued by Karen and is still looking for a home (if you are please send an email here)! I'm sure all of you want to keep hearing about my adventures with the cats I worked with, but I want to highlight the true purrrpose of CPAW NJ. After all, it wasn't the experiences with the kittens that I value most from CPAW. 

Picture of Oreo photographed by Alina (another volunteer)

Overpopulation can easily occur in cat communities due to the sexual behavior of female cats.  Cats reach sexual maturity at around 4 months old, so they have kittens much faster than a lot of animals. Cats, like rabbits, have heat cycles which occur every 12-22 days causing a release of hormones and a change in behavior that attracts new mates. In their period of heat, which can last from 2 days to 2 weeks, many male cats will mate with the female causing a large mix of genes. Once the cat gives birth, they can be fertilized again in as little as 2 days. This means that the cat population can get out of hand quickly. This cycle can also have effects on the mother because she can over exert herself when having litters so often. Cats can give birth to new litters 5 and a half times a year. This quick birth rate is all supposed to give cats a higher chance to pass on their genes, thus having high fitness. Currently, there are 500,000 cats on the streets of NYC, imagine in the entire US! Of course, governments have taken measures to try to regulate this cat population.

Cat population statistics brought to us by the CPAW NJ Facebook page

Traditionally, it is common for governments to utilize the option of trap and kill to handle their overpopulation of community cats. Trap and kill is when the government orders their animal control officers to lower the population of cats through the mass murdering of the population. However, this has shown to be ineffective due to the scientific phenomenon known as the vacuum effect. The vacuum effect is a description of what happens when a large piece of a population is removed: in some time, the population will bounce back because the resources in the community are now available. Immigration occurs as more animals try to take advantage of open shelters and plentiful food. Some people may be then drawn to the idea of adoption for these cats, however, this solution is also problematic. 

Yes, we always love to see a rescue mission that involves finding an animal a home. But sometimes, that is not always possible. There are strays on the street who would do much better in a home, these cats are usually banged up and ill prepared for defending themselves on the streets. Feral cats, however, have been raised in the wild. They are usually unfit for adoption because they have not been socialized. Cats need proper socialization with humans as kittens in order to become pets. If a cat is not properly socialized at the beginning of its life, it is likely that cat can never be a house pet. Without socialization, a feral cat will become stressed around humans and display aggressive behavior like hissing, spitting, and running away. Cats like Jack and Turner were lucky to be socialized as kittens because they can be adopted. However, if a cat shows any sign of being feral, they are usually euthanized in shelters for being wild. Statistics show that over 70% of cats are euthanized in shelters. 

This image shows a pyramid of actions to best reduce the cat population
https://www.communitycatspodcast.com/introducing-the-community-cat-pyramid/

This is why Karen started to spread the message of TNVR. This practice provides a humane way to handle outdoor cats while also fixing the communities' overpopulation issue. Instead of killing the cats caught by animal control officers, the goal is for cats to be neutered/spayed, vaccinated, allowed to heal, and then released back to where they were found. There are many benefits of TNVR for the cats's health and human life. For one, studies have shown that TNVR instead of trap and kill improves morale and happiness in animal control employees. The amount of euthanasias in shelters decreases significantly after a TNVR practice goes into effect. Not only that, but community cats play an important role in our environment's ecosystem. They fill in a specific niche that we should all be grateful for: small animal control. They hunt rats and mice so that the rodents cannot enter our houses. If not for community cats, our town could end up like Chicago did when it had a 3 month wait list for community cats due to a lack of rodent control. In that same matter, TNVR also prevents overconsumption of small birds and other wildlife by keeping a limited number of predators. TNVR also promotes cheap spay and neutering for pet owners. This means that humans can have easily accessible surgery that benefits the lives of their pets. In Montclair, CPAW NJ runs a monthly spay/neuter van in their campaign called Beat the Heat.

 As for the cats, the vaccinations allow the cats to become resistant to rabies, which also benefits us. The trap, neuter, and release practice allows for behavioral changes like reduced territorial fighting. The cats live a safer life with less injuries and resistance to diseases that would normally spread quickly in communities. When the cars are sterilized, they usually stop their sexual behavior. This prevents vocalized mating, a common behavior that many people are irritated by. In addition, cats can no longer have kittens in the cold outdoors where most of them usually die. To ensure they don't mistakenly attempt a second sterilization on the same cat, TNVR organizations tip one ear of the cats who have already been neutered. This is why it is important to look for that tip! Not only does TNVR result in a cheaper and practical solution to overpopulation, it also has countless studies that support that TNVR is beneficial for all parties. 

community cat inside a trap about to be checked up. The cover allows
for the cat to calm down. Photo from the CPAWNJ facebook.

With all these benefits for TNVR, it's crazy that it hasn't been implemented widely. Sadly, the true issue that prevents TNVR from spreading is the lack of knowledge. Many officials in government often say that spay/neutering will not solve the problem. This is why CPAW NJ tries to spread this awareness in communities. It solves the long term problem of overpopulation while giving cats the best chance of surviving in the outdoors. TNVR organizations also face additional challenges. Traps require food for the cat to eat as bait. Without it, no cat would enter the trap and no neutering would happen. Karen told me recently that many towns will tell her they believe in TNVR, but will not legalize feeding feral cats. Notably, another issue is that many governments mandate TNR registration. People who run TNVR efforts are forced to share their personal information. The government also considers the cats that are recovering in the operator's care as the operator's personal property. This in turn makes them violate maximum cat allowance ordinances.  

tipped ear cat from CPAW NJ website.

If you have been particularly inspired to help with this message, please check out the CPAW NJ get involved page! The people here are kind, considerate, and willing to teach you. CPAW not only handles spay/neuter and TNR, they also handle surrender prevention by providing behavior advice, cat care for beginners, and even lost cat aid. CPAW NJ has taught me how important a cat can be to our human-made ecosystem. That, and gave me the important job of teaching about the tipped ear. 

Team City Bird vs. Team Country Bird

For those who have encountered the combatant pigeons of New York City, it likely comes as no surprise when I say that birds that live in the city have different behavioral patterns. The environmental conditions in the city are so drastically different than those of rural areas, that they place a selective pressure upon the birds, causing them to biologically adapt over time. In some ways, the pressures caused by city life can improve populations of birds, and in other ways, they are put at a disadvantage.

Birds in the city are forced to face several environmental differences that affect how they must behave to survive. There is a heightened amount of stimulus as well as population density in cities. At any given moment, there is noise, traffic, bright lights, and many people and different types of animals fighting for space and resources. In order to survive and reproduce, city birds tend to be forced to adopt a more aggressive demeanor and be willing to fight and assert themselves when necessary.

When observed, urban birds show off their aggressive sides in response to trouble. Much of this comes from biological evolution over time, but in addition to the foundation that evolutionary tendencies provides, the frequency of exposure to situations like these makes the birds better equipped for conflict going forward. Birds in the city also show raised aggression during mating as a result of the density of competition.

Additionally, it was found that city birds may even have a greater immune system and higher intelligence than country birds. I would hypothesize that their immune system would be better as birds are exposed to a much less clean environment, exposed to pollutants and food scraps, and therefore would naturally build antibodies to different pathogens more quickly. They could also have become genetically predisposed to have a better immune response over generations (read more about inherited immunity here).

One downside of life in the city for birds is the potential of more stress, which can shorten the length of their telomeres. Telomeres, which are like caps on chromosomes, shorten over time, and their shortening can decrease one's lifespan. With exposure to a great amount of stressors, city birds may face more wear and tear than country birds.

It is up to you whether you find that city birds or country birds are superior. Frankly, there is no true purpose in determining which type of the amazing creatures reigns supreme. City birds seem to mirror their human city-mates, having to endure great stress, but resultantly becoming more aggressive and well-equipped in the face of conflict. Country birds are not as likely to have these traits, but they also face much less external stress. The choice is up to you; Team City Bird or Team Country Bird?