Dr. Gary Schoolnik discusses cholera from medical, epidemiological, ecological, and economic perspectives, focusing on the links between agricultural practices, particularly the advent of chemical fertilizers, and climate change on cholera epidemics in South Asia.
He opens by offering several levels of analysis for disease, with their corresponding implications (medical, epidemiological, etc.)
He presents a video of Bangladesh, demonstrating a cholera outbreak and its harmful effects (Ghost Map is about tracking and fighting cholera in London). Rice water stool - milky and whitish cholera filled stool that results from the infection. It's spread through drinking contaminated water and, less frequently, by eating contaminated food. He notes that some residents defecate directly into their water supply, which is an excellent way to spread cholera and also disgusting. This creates the cycle in which it explodes into an epidemic and gets moved back to the water for further drinking. Epidemics occur around bodies of water. Sometimes it travels in the ballast water of large ships.
Climate (monsoon cycles) connects with cholera outbreaks. Thus, any weather changing events that increase rainfall increase the risk of cholera outbreaks. Post monsoon algal blooms precede the cholera outbreaks. Algal blooms are the result of sunlight and nitrogen being added together in the algae's environment. The monsoon rains create runoffs that bring nitrogen rich chemical fertilizers and human/animal wastes into the water.
Cholera bacteria are harbored by copepods. Copepods are numerous sea borne creatures that are related to lobster, shrimp, etc. and have a similar structure, though they are much smaller. They have a chitin containing exoskeleton, which is an abundant biopolymer. The cholera attaches, causes the chitin to tip over and then sprouts out like an old potato.
Competence for natural transformation - capacity to take up naked DNA into its own genome. The bacteria can make a quantum leap by simply grabbing effective DNA from the outside world. This horizontal gene transfer generally requires that similar sequences of DNA surround the DNA to be added; this enables the bacteria to pair up its own DNA with the new stuff. Thus most of the acquisitions will occur within related bacteria (same genus, not necessarily same species). There is a mechanism involving viruses for adding less matched DNA from a more distant relative. (This is the RNA side of things - think HIV which invades cells and begins running instructions for its own benefits. Humans are able to use the polymerase chain reaction along with an innocuous virus to introduce snippets of DNA into our own cells - in tests - and bacteria have a similar natural capability).
When it doesn't take the DNA up altogether, it can degrade the source material to nucleotides and then take those up instead.
This gives it the capacity to make big leaps in effectiveness.
It's believed 013 Bengal Cholera picked up a new DNA sequence that cloaked its surface and made it impossible for the host's immune system to recognize the disease immediately. This began a new sequence of suffering for adults that had previously been infected and would have had acquired immunity.
So the Green Revolution in Asia was good for food, but the massive use of chemical fertilizers helps feed cholera blooms. Plus deforestation. Plus global warming effects.
On the bright side, with clean drinking water and hygienic disposal of feces, cholera is stopped cold (unless you eat improperly prepared crab from the Louisiana area, which you properly will if you went to Cal).
He opens by offering several levels of analysis for disease, with their corresponding implications (medical, epidemiological, etc.)
He presents a video of Bangladesh, demonstrating a cholera outbreak and its harmful effects (Ghost Map is about tracking and fighting cholera in London). Rice water stool - milky and whitish cholera filled stool that results from the infection. It's spread through drinking contaminated water and, less frequently, by eating contaminated food. He notes that some residents defecate directly into their water supply, which is an excellent way to spread cholera and also disgusting. This creates the cycle in which it explodes into an epidemic and gets moved back to the water for further drinking. Epidemics occur around bodies of water. Sometimes it travels in the ballast water of large ships.
Climate (monsoon cycles) connects with cholera outbreaks. Thus, any weather changing events that increase rainfall increase the risk of cholera outbreaks. Post monsoon algal blooms precede the cholera outbreaks. Algal blooms are the result of sunlight and nitrogen being added together in the algae's environment. The monsoon rains create runoffs that bring nitrogen rich chemical fertilizers and human/animal wastes into the water.
Cholera bacteria are harbored by copepods. Copepods are numerous sea borne creatures that are related to lobster, shrimp, etc. and have a similar structure, though they are much smaller. They have a chitin containing exoskeleton, which is an abundant biopolymer. The cholera attaches, causes the chitin to tip over and then sprouts out like an old potato.
Competence for natural transformation - capacity to take up naked DNA into its own genome. The bacteria can make a quantum leap by simply grabbing effective DNA from the outside world. This horizontal gene transfer generally requires that similar sequences of DNA surround the DNA to be added; this enables the bacteria to pair up its own DNA with the new stuff. Thus most of the acquisitions will occur within related bacteria (same genus, not necessarily same species). There is a mechanism involving viruses for adding less matched DNA from a more distant relative. (This is the RNA side of things - think HIV which invades cells and begins running instructions for its own benefits. Humans are able to use the polymerase chain reaction along with an innocuous virus to introduce snippets of DNA into our own cells - in tests - and bacteria have a similar natural capability).
When it doesn't take the DNA up altogether, it can degrade the source material to nucleotides and then take those up instead.
This gives it the capacity to make big leaps in effectiveness.
It's believed 013 Bengal Cholera picked up a new DNA sequence that cloaked its surface and made it impossible for the host's immune system to recognize the disease immediately. This began a new sequence of suffering for adults that had previously been infected and would have had acquired immunity.
So the Green Revolution in Asia was good for food, but the massive use of chemical fertilizers helps feed cholera blooms. Plus deforestation. Plus global warming effects.
On the bright side, with clean drinking water and hygienic disposal of feces, cholera is stopped cold (unless you eat improperly prepared crab from the Louisiana area, which you properly will if you went to Cal).
