This is a speculative piece about influenza, why it exists and why it seems to be getting worse. Yes, we travel more. Diseases are easier to spread. But I think there is something else going on, something about the 20th century that made pandemics of influenza inevitable.
Here is the story of influenza from the bits and pieces I have been able to gather from online research. I will put the links last to improve the narrative flow. Basically, this is the story of a brave little snail and his buddy the nematode and the forces of evil---man, birds, rats, seals, pigs---that wanted to gobble the juicy little snail up, especially during times of crisis, like the occasional ice age or volcanic winter, when geothermal springs were one of the few places with abundant life and snails were one of the tastiest morsels around (unless you happened to enjoy eating pond scum). Poor snail! So plump, so juicy! So defenseless, hiding in his little shell.
“Psst,” said a voice from within snail’s tummy. It was nematode, also known as roundworm. “I have an idea. I will whip up a batch of poison and you use your slime to smear it around and when those pesky birds” (this snail lived in a pond) “come looking for you, they will find death instead.”
“Hmmm,” said the snail. “I like it!”
That’s the story. Here’s the theory.
Influenza has been around for thousands of years. The Greeks described influenza type illness in detail. And snails have been a staple of the diet of Mediterranean peoples for tens of thousands of years.
In the late 19th century, the first big documented flu epidemic, the so called Russia flu occurred. But that was nothing compared to the Influenza A of 1918. Years later, scientists would trace the influenza that caused the deadly 1918 pandemic to pig lungworms, a type of nematode. File that away for later reference, too.
A few decades passed. And then we got Asian Flu in 1957 and Hong Kong Flu in 1968 and Swine Flu in 2009. And in recent years, we are seeing the emergence of new strains faster than vaccine manufacturers can keep up. Why?
Here is my model for influenza. I think that the virus lives inside nematodes that live inside snails. The nematodes have a symbiotic relationship with their snail hosts. When the snail population is threatened, the nematodes get to work releasing influenza virus which just happens to target some of snails biggest natural predators---birds, especially aquatic birds like ducks, wild boar, rats, seals, humans. Plus, the snails (which benefit if their natural predators come down with flu) secrete a substance that allows influenza virus to survive for extended periods of time outdoors, waiting for some hungry duck to pick it up, contract flu and infect its flock--it is the snail secretion studies as well as the fact that seals and humans are the only two targets of flu b and the main food source we have in common is mollusks that made me think about snails as the likely prey that influenza is meant to protect.
There have been snails for a very very long time. There has been influenza for at least a few thousand years. What changed in the last one hundred years? Not travel. In 1918, people had been moving around by train for decades. Airplanes would not be commonly used for another thirty years. It cant just have been the world war. There was no influenza epidemic immediately after WWII.
I think we saw the rise of influenza because of the agricultural revolution that took place in Asia in rice farms. It began in the early 20th century. And then, in the mid 1950s, in China, it took off again. Increased production meant increased swampland full of rice which attracts snails. Rice farmers use ducks as natural pest control. The combination of an increased number of snails with their nematodes that can carry influenza--note that nematodes have been shown to be excellent vectors for phages or viruses---along with an increased number of ducks that can catch influenza and an increased number of humans that can also catch influenza all living in close proximity is the perfect natural petri dish for brewing up lots of flu and encouraging lots of genetic shifting.
Now, as promised, links:
Guess what? There is a major avian influenza epidemic every 2-4 years. And scientists have been unable to figure out where the flu virus hides between outbreaks.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2660440/
“Avian influenza virus (AIV) persists in North American wild waterfowl, exhibiting major outbreaks every 2–4 years.”
“Avian influenza viruses (AIVs) in wild waterfowl constitute the historic source of human influenza viruses, having a rich pool of genetic and antigenic diversity that often leads to cross-species transmission. Although the emergence of H5N1 avian influenza virus onto the international scene has captured the most attention, we do not as yet understand the mechanisms that underpin AIV persistence and dynamics in the wild. We developed a novel host–pathogen model intended to describe the epidemiology of low pathogenic AIV in temperate environments. Our model takes into account seasonality in migration and breeding together with multiple modes of transmission. AIVs have been detected in unconcentrated lake water, soil swabs, and mud samples. Laboratory experiments show that AIVs persist and remain infectious in water for extended periods. However, so far, the possibility of environmental transmission of AIV has been largely overlooked. Our work shows that environmental transmission provides a parsimonious explanation for the patterns of persistence and outbreaks of AIV documented in the literature. In addition to their scientific importance, our conclusions impact the design of control policies for avian influenza by emphasizing the dramatic and long-term role that environmental persistence of pathogens may play at the epidemic level.”
We should get the guys who wrote the article above together with the authors of the next article. They conclude that snails secret a slime that allows influenza to survive outdoors.
https://www.omicsonline.org/open-access/potential-role-of-fresh-water-apple-snails-on-hn-influenza-virus-persistence-and-concentration-in-nature-2167-7719.1000119.php?aid=38277
It could be the snail all by itself, but nematodes (round worms) have been described as natures perfect taxis for phages.
“Strikingly, the pig lungworm nematode has been implicated in directly transmitting the virus responsiblefor the 1918 influenza pandemic (30-33), but the potential role of nematode vectors in future flu or other viral disease epidemics is seldom discussed.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1393236/
Phages are bits of DNA and RNA that infect and grow within bacteria. They get things done from an evolutionary standpoint. And they can confer resistance. But how do bits of DNA and RNA get from one bacterial population to another? They don't have legs. They don't have wings. They don't have cars. They don't have phones so they cannot call Uber. If they want to get around they have to hitch a ride. And what better vector (taxi) than the nematode which is everywhere?
Ok, but how do I link nematodes with the influenza virus? Easy. I google.
Check out this study. Give rodents nematodes and then infect them with influenza and the virus goes to town. Something about the nematode assists the influenza in doing its dirty work. And rats are notorious for their love of nice fresh juicy snails.
Interaction of Nematospiroides dubius and influenza virus in mice
Author
Wieslaw Chowaniec 2, Richard B. Wescott 3, Larry L. Congdon
https://doi.org/10.1016/0014-4894(72)90007-0
Abstract
“The response of mice infected with Nematospiroides dubius to influenza A2 virus was studied in a series of four experiments. Groups of mice, given 50–1000 N. dubius larvae, subsequently were exposed to virus and killed for examination. The amount of virus present in lungs, hemagglutination-inhibition (HI) antibody titers to influenza, and numbers of adult N. dubius present were determined. Significantly higher antibody titers were found in nonparasitized controls than in parasitized mice in all experiments. These differences were most apparent in mice killed 21 days after exposure to virus. The greatest reductions in HI titers were observed in mice given 1000 larvae although mice that received fewer larvae usually had significantly lower titers than nonparasitized controls. The titers of virus present in the lungs of parasitized mice 2 days after exposure tended to be lower than in nonparasitized controls.”
Nematospiroides dubius is a rat parasite that hijacks the immune system of the rat in order to achieve a chronic infection state. In the process of hijacking the rat immune system, it also makes the rodent more vulnerable to influenza. See? The great circle of life. Or the great circle of death.
When I first started my research, I was suspicious of cicadas. They have that odd every 13 or 17 year emergence cycle. And bird populations have been shown to decline in the year before a cicada emergence. However, I now think that cicadas may just be taking advantage of the every 2-4 year year avian influenza epidemics. 13 and 17 are both four times x plus 1, meaning that cicadas who emerge in these years are likely to come out just after a bird flu epidemic.
Oh, one more strange thing. As of about ten years ago, we now have a new influenza, one that infects cows. How? How are cows getting influenza a disease of omnivores? Has someone been feeding cows ground of snails instead of ground up cow brains? Snail feed for animals is very popular right now. But it is not supposed to be given to cows since some types of snails carry liver flukes. No cattle rancher would ever give a cow something that might make the cow sick, would he....?
http://mbio.asm.org/content/5/2/e00031-14.full
https://www.feedipedia.org/node/200
https://burnabyredwigglers.wordpress.com/2015/12/01/compost-worms-as-a-source-of-protein-for-animal-feed/
Disclaimer. This is a theory. It has not been proved.
