Last Portion of Class (Minamata Disease -) Flashcards
Where did Minamata Disease first occur?
A fishing community on the West coast of Japan in Minamata Bay in the 1950s -> first saw it in animals in 1952 and then children among the first sufferers in 1956.
- a wide variety of seafood was harvested from Minamata Bay: oysters and clams.
What was the timeline of Minamata Disease?
- In 1908 they built a chemical fertilizer factor Chisso Corporation factory in Minamata.
- In the1920s and 30s, they greatly started to produce fertilizer from this company.
- From 1932, Chisso started to use mercury in its products. -> from 1932 to 1968, Chisso dumped methyl mercury (a waste by-product) into Minamata Bay.
- In 1952, residents of Minamato started noticing concerning signs in animals.
- Feral cats who ate fish scraps from docks of Minamata Bay started exhibiting weird pyschological signs
- Ran into rocks, jumped into the sea and drowned, seizing
- Most of the cats in the fishing village ended up dying
- Soon after, people started showing alarming symptoms as well
- Delusions, tremors, delirium
- Children among first sufferers in 1956.
Researchers tested sediments at the mouth of the wastewater canal in 1959 and found up to 2 kg of mercury per ton of sediment—enough to be economically viable to mine.
Second outbreak in Niigata on Agano River in 1964-65. (like Chisso factory, also used mercury catalyst)
1968 → 12 years after discovery of the disease → Chisso stops production with the product → compensation for ppl
What did people of the Minamato Bay area first think Minamata disease was?
Thought it was a new contagious disease (bc it was highly localized): an “epidemic of an unknown disease of the central nervous system.”
What were the symptoms of Minamata Disease?
- People reported loss of sensation, difficulties seeing, hearing and swallowing.
- Followed by severe convulsions, coma and death.
- Mortality rate of 30% among those who got it
- Epidemiologically studies showed not contagious disease but rather due to seafood
- Suspected it was heavy metal poisoning
- Hypothesized it was mercury poisoning
- Mercury bioaccumulates → doens’t get flushed out of your body: neurological effects
- Found it high in pregnant women → miscarriages and found cerebral palsy in children
Who was Hajime Hosokawa?
- Chisso factory doctor
- Did an experiment on feeding waste water to a cat
- Him and company knew way before it started in the population how dangerous the disease was
- Some of the 138 plaintiffs in the first Minamata disease damages case against the Chisso Corp. leave Kumamoto District Court on March 20, 1973… FINISH NOTES
- Really just was acute mercury poisoning
What was the case of mercury poisoning in Canada?
- Grassy Narrows → pulp company dumped waste water into river
- Mercury contamination found in Freshwater fish
- When they realized there were elevated mercury levels in the fish, they closed the sports fishing industry and commercial fishing industry there
- Annishinaabe also relied on fish in their diet
- Closing of factory → economic consequences → more turned to eating the fish
- Solicited medical tests to see if they’re being exposed
- 1973 → found that their hair samples had 12x the normal amount of mercury; and 50x more (elevated) levels of mercury in their blood
- Speaking difficulties, similar symptoms to those in Minamata
- Since 1970s → efforts to address mercury poisoning in Ontario
- Japanese came over to suggest methods to test them
- Found it was the pulp mill leading to mercury contamination
- But a lot of that mercury remains in the environment
- But help for these problems remain elusive in many respects
- Not just mercury poisoning, but advocated by other sources of heavy metals/contamination in the waterways
What was the deal about New Environmental Diseases?
- Not as deadly as infectious pathogens.
- Many came about in the context of new technologies and compounds applied to industrial production.
- Novel chemicals, new uses of old substances, found their way into human bodies in many different ways
- Workplaces
- Households
- Wider environment
- In case of Minamata → new technologies using chemicals that disemminated into the wider environment
What were the first Polio vaccines?
- Sabin vaccine was available in 1962
- More successful in the long run bc you could administer it much more easily (could drink it) → went into the gut → most effective (bc polio is an intervirus)
- Easier to administer in rural areas because it required less sterile equipment and got rid of fear of vaccine
- Much weaker version of the virus → passed it through tissue cultures to weaken it → ppl ingest it → goes into gut → ppl pass it in stool as well → in places with poor sanitation other ppl would be exposed to it as well which would achieve wider coverage (weak version evoke an immune reaction in them)
- Salk vaccine was the injected vaccine and first one available in 1985
- Global vaccine campaigns were highly successful
- Number of polio cases falls dramatically with Salk vaccine (first) and then with the Sabine vaccine in 1980s
- By May 1988 they eradicated smallpox
- Next major goal was to eradicate polio globally
What were the results of the Global Polio Eradication Initiative?
- The eradication campaign has been in many respects highly successful
- Types 2 and 3 thought to no longer exist in nature
- Number of cases globally has declined dramatically (about 90% since beginning of campaign)
- Still is number 1 serotype out there:
- WPV1
- cVDPV: vaccine-derived virus → arises from mutation of the live virus in the vaccine
- In some instances, once it is excreted in the ppls stool it is mutated into a more severe version that causes paralysis and death.
What diseases have been successfully eradicated?
- Smallpox: the only human disease to have been successfully eradicated from nature.
- Rinderpest: Animal disease successfully eradicated (2011)
What was the history of Smallpox and Vaccines?
- Earliest vaccine developed.
-> Sabin oral vaccine in 1962
-> Salk vaccine was the first injected one available in 1985. - Had thought would confer lifelong immunity, but soon realized would need boosters.
- Compulsory vaccination programs often targeted at children.
Epidemics would prompt new vaccination programs often targeted at children.
Mandatory smallpox vaccine campaigns would be enforced by saying their child could not go to school unless they were vaccinated.
What was the smallpox vaccination campaign like in the Phillipines?
- San Jose College Manila University 1887
- Smallpox had long been a problem in the Philipines, under Spanish rule they had a pretty good health program
- Quarantines
- Spanish disseminated vaccine lymph for 1806 on.
- Phillipines had public health department from 1883
- Provisions for isolation and quarantine
- By 1898 there were 122 regular vacunadores (vaccinators) working in provinces and major towns.
- Vaccinators usually weren’t paid well, so not much motivation to vaccinate people.
- Problem with early vaccination campaigns → vaccination/virus very weak → hard to get it work
- In other instances, vaccines were contaminated with bacteria → more issues, opposition
- Spanish-American War (1898) → public health system collapse → America took over public health system
- Established separated hospitals for smallpox, leprosy, etc.
- Established a smallpox vaccination campaign
- 103,931 vaccinations in Phillipines 1899
- In 1902 → teams would enter the most crowded houses (with army) and lead ppl out of the house 1 by 1 and anyone who did not have smallpox scars would be vaccinated.
- Colonial force
- Carried out on ppl seen as below the ppl in power
- 18 million by 1914
- 1929-30, endemic smallpox eradicated
- Vaccination programs helped establish colonial apparatus.
- Epidemics were persisting even as smallpox was being locally eradicated around the globe.
What helped in the eradication of smallpox due to vaccination campaigns?
- Epidemic persisted even with compulsory vaccination.
- Highly visible symptoms that enabled quick identification of disease (unlike TB for example)
- No reservoir in other animals (unlike plague)
-> Human disease - Only transmitted between humans - no vectors involved (unlike malaria, influenza) -> why smallpox eradication was seen as a possibility.
What was Russian Smallpox Eradication like?
- Russia had a long history of large-scale vaccination campaigns. Central medical authorities worked with local governing bodies to distribute vaccines.
- Soviet government imposed compulsory vaccination of the entire population in April 1919.
- Effective technique for rapid vaccine production and widespread dissemination.
- Successfully eliminated smallpox between 1936 and 1938.
When did new attention to Global Health happen?
- In the wake of WWII.
- World Health Organization (WHO) created in 1948.
- USA smallpox free in 1949.
- In Cold War context: Disease eradication offered possibilities for ‘technical cooperation’ between the USA and USSR.
- For WHO offered opportunities for it to asserts its role in the post-war world.
Who was Viktor Zhdanov (1914-1987)?
- Soviet deputy minister instrumental in persuading WHO to approve global smallpox eradication campaign.
- If you have enough people that are immune, then the virus can’t find a host and dies out.
- But challenge was you could not vaccinate everyone, everywhere, all at once.
-> Eg. India -> everywhere so spread out. - Costs were seen as prohibitive.
What was Smallpox eradication like in Nigeria?
- In December 1966 there was an occasion of a new mode of pursuing eradication.
-> Team faced with a smallpox epidemic in an area -> took what limited supplies they had -> identified new cases, isolated them, and traced ppl who had been in contact with those cases and vaccinated them. -> just those who had been in touch. - Within 5 months, the chain of transmission had been broken even tho less than 5% of the population had been vaccinated.
- Led WHO to focus more on containment instead of mass vaccination. -> identifying, and finding contacts. -> led to surveillance and containment strategy.
-> Also in India where ir found great success. - As much about administration and control as it is medical expertise.
When was the last case of smallpox?
October 1977.
- Ali Maow Maalin (1954-2013) living in Mogadishu, Somalia. Last known “natural” smallpox cases before eradication of the virus. Maalin went on to lead polio vaccination campaigns in Somalia.
- Since 1984 there are only two locations globally where variola virus is officially stored and handled under WHO supervision.
-> No more natural smallpox, only captivated/captured smallpox in Russian and US.
Who was Janet Parker?
- Last known person to die from smallpox in September 1978.
- She contacted the disease from a medical research laboratory.
- Debate about decisions to continue to keep the variola virus.
-> Some said we should eliminate it from nature forever (didn’t need the virus for vaccine production bc vaccine is made from cowpox) -> some said we should keep it to compare it when new disease occur.
-> Ethical argument: just bc its harmful to humans doesn’t mean we should eradicate it. -> own right to existence.
What were the 2 big themes of the post-war period in terms of disease?
global disease control and emerging pathogens.
-> In late 20th c. had a new sense of emerging pathogens due to increased surveillance of disease.
Review: Smallpox: Vaccination to Eradication compared to TB
- Epidemics persisted even with compulsory vaccination
- Highly visible symptoms that enabled quick identification of disease.
(unlike TB, for example)- TB eradication is hard bc its hard to control the disease when you can’t tell who has it
- No reservoir in other animals
(Unlike plague) - Only transmitted between humans - no vectors involved
(unlike malaria, influenza)- mosquitos
What was Malaria Eradication like in the post-war period?
- Vector-borne disease, do you eradicate the parasite? Or the vector? Or both?
- vector: anopheles mosquito
- Intersection of the history of pesticides (DDT) with the history of anti-malaria medicine.
- WW2 - Pacific theatre and globally, malaria and typhus major sources of illness.
- major cause of death
- spread by mosquitos and lice
- and by time of WWII researchers knew they were the critters involved
- Insecticidal value of dichloro-diphenyl-trichloroethane (DDT) identified in 1939.
- and becomes available as a highly effective pesticide
- applied significantly during the war to control typhus and malaria
- Widespread spraying of homes in Siciliy, Italy to prevent spread of malaria
- effective bc it did kill mosquitos
What were the downsides of using DDT to deal with Malaria?
- DDT is a persistent organic pollutant (POP)
- Resistanct to breakdown through usual chemical and biological processes
- Persists in the environment and can be transported long distance, including tavelling up food chains
- Bioaccumulates
- Harms of DDT are largely environmental harms → bc it biomagnifies and bioaccumulates → significant harm to bird population, good and bad insects → killed lots of birds
- Also was being detected in human bodies and correlation to some degree to cancer
- By 1970 DDT is banned is US except when used to control malaria-carrying mosquitos
- Still used around the world to control malaria around the world
- Toxicity of DDT to humans and other creatures is one problem of it
- Other is evolving pesticide resistance of infects and other pests
- 19th-20th c. → backfired → pesticide and antibiotic resistance
Charles Darwin and Natural Selection in reference to Disease
Natural selection - if there were natural variations in organisms that were beneficial to survival then those who had those characteristics, passed them on to their offspring → creatures with those characteristics more likely to prevail.
What was the evolutionary problem that occurred when dealing with malaria using DDT?
millions of flies could come from two successful flies breeding → rapid evolution
- Bc of the scale of insect reproduction you can have evolutionary change in a matter of years.
- A few individuals where resistant to the insecticide → survived spraying → reproduced → if the resistance was inheritable, it carried on to their offspring → natural selection
- By 1970s, they were already talking about the resistance to insecticides in insect populations to DDT
- Can see this in the increase of bed bugs and cockroaches in the present
- Reason we are seeing more of these pests is climate change but more than that it is bc the arsenal we had to get rid of these creatures, these creatures have evolved resistance to them.
- Malaria is the oldest and with tuberculosis, cumulatively deadliest human disease.
- Kills between 1 and 2.7 million people each year.
- Most are in Africa between 1 and 5yrs
- History of treatment has included efforts to treat effects on human body and to control mosquitoes
What is Quinine and what is it used for?
- Available from 16th c.
- From cinchona bark
- Impedes growth and reproduction of malarial parasites (plasmodia) in red blood cells
- (but if elsewhere in body, parasite could reinfect blood)
- Cinchona plant found in Peru.
- Component of tonic water → used it in India to help treat malaria
- Tied up in colonial history
- Cinchona native to the Americas → but planted in India to try and stop spread of malaria
- Part of the challenge is that quinine cannot be synthesized
