bio hazards
TRANSCRIPT
Greg Doyon
Food:
Mad Cow Disease (vCJD)
Vector:
Malaria
Water:
Cryptosporidium
Aerosol:
Tuberculosis
Mad Cow Disease or variant Creutzfeldt-Jakob Disease overview:
Mad Cow Disease is to cows as vCJD is to humans.
Mad Cow Disease = Bovine Spongiform Encephalopathy
BSE is a degenerative brain disease in cows that comes from a prion aka misfolded protein
These prions infect proteins within the brain to cause microscopic “holes” in the brain
Creutzfeldt-Jakob Disease (CJD) Is a degenerative brain disease that affects
humans aged 45-75, but 60-65 is the most vulnerable population
Creates a sponge-like texture in the brain variant Creutzfeldt-Jakob Disease (vCJD) Comes from eating beef tainted with BSE or Mad
Cow Disease
Degenerative brain disease that is known to affect people in their 20’s.
Origins: 2 Hypotheses:
1st: BSE comes from the disease Scrapie▪ Scrapie affects the lymph nodes of sheep and is also
based on Prions.
▪ Cattle ate contaminated sheep with Scrapie
2nd: BSE comes from a single cow.▪ A sporadic case of BSE forms in a cow and is spread
through the feed.
▪ Most recent evidence suggest this is the most possible cause
Genetic Factors affecting humans:
PRNP
▪ Gene that encodes the prion protein
The PRNP locus was strongly associated with risk across several markers
▪ Basically the position of this gene on a chromosome
The polymorphic codon 129 of PRNP was the main genetic risk factor for vCJD
(Mead, S. et. al, 2009)
Hard question to answer. Practices
If BSE originated in a sporadic fashion than it seems as though this could have happened anywhere.
Possibly England was using a different antibiotic than other modern countries.▪ Recycling of antibiotic meat or even just recycling of
cattle
▪ Possibly a new mutation occurred?
Ireland had a significantly lower number of BSE cases compared to England 1,353 vs. 183,841. Ireland’s primary method to feed cattle is
predominately grass based In U.S.A., we feed our cattle with Soybean Meal
and Cotton Seed Meal Ban on feeding cattle with remains from other
animals Much less expensive 3 cattle had BSE, at least 1 came from Canada
Farms are in rural parts of the country, however contaminated meat is being shipped through out England.
Preference to live in city away from farms
Mosquito-borne infectious disease Caused by eukaryotic protists Prevalent in Equatorial regions of the world
Thrives in warm rainy areas
Environment allows mosquitoes to breed constantly
Causes headache, fever, coma, and death
Malaria was very prevalent in late 18th century England: Deaths per 1,000 per year
18th
Century Essex, England
18th
Century Essex, England
20th
Century Garki, Nigeria
Age NonMarsh Marsh Savannah
5 44 95.3 154
6-10 6.3 9.4 15
11-15 6.8 10.8 10
16-20 8.4 12.7 6
http://www.cdc.gov/ncidod/eid/vol6no1/reiter.h
tm
Question: What brought Malaria to the marshes of England in 17th and 18th Century?
Answer: Climate change
The climate had naturally become warmer as it is constantly going through waves of warming and cooling
Why is this important now and is it a threat? What other threats of Malaria exist as well?
In 1975 WHO, declared Europe “Free of Malaria”
Mass mosquito spraying, England as well
In 1977, 83% of the world was Malaria Free, with only Sub-Saharan Africa being affected.
As time went on, Malaria started to reappear first in South America, tropical Asia, and some Mediterranean countries.
Some theories of the resurgence of Malaria include:
Deterioration of Vector control
Urbanization
Clearance of forests
Population increase
Resistance to insecticide
Climate change
Yes, with the resurgence of Malaria and increasing global temperatures, the marshes of Southern England could again be stricken with Malaria
“The researchers have calculated that if global warming continues at its current rate, some of these same areas could once again become breeding centres for malaria for up to four months each year by the end of this century.”
http://news.bbc.co.uk/2/hi/health/1775427.stm “UK faces summers of malaria” (2002)
If Malaria does come back to England, likely to occur in: Southern Marshes
Northern England will be safer due to cooler temperatures
No imminent outbreak about to occur, however there is a very strong possibility that it can return to the English Marshes
Best way to control: IPM
A protozoan parasite found in contaminated water
Can colonize and reproduce in the intestines of humans and other vertebrates
Develops into an oocyst which is extremely hard to destroy
Spread through the fecal-oral route Main symptom is diarrhea
Can be fatal in immunocompromised people such as AIDS patients
http://upload.wikimedia.org/wikipedia/commons/7/73/Cryptosporidio
sis_01.png
Crypto has been the most prevalent infectious water-borne disease in the past 10 years in England. (Jones, M. et al, 2006)
In England and Wales between 1992 – 2003, Crypto was responsible for 70% of all water-borne outbreaks (Smith, A. et al, 2006)
(Smith, A. et al, 2006)
Swimming Pools contaminated with Crypto:
Regular treatment should reduce risk
Nearly impossible to prevent point-source infection
Crypto oocysts can been introduced by accidental fecal release by young children
Parents should prevent children with gastrointestinal distress from swimming in pools
(Smith, A. et al, 2006)
August 2003
Outbreak of Crypto in children following a visit to an “adventure park” in SW Rural England
Several activities included water, water rides, and contact with farm animals
Took water samples at various locations
Took stool samples of the farm animals▪ (jones, M et al, 2006)
91 children got sick Median age was 6 94% reported diarrhea 64% vomiting 62% abdominal pains 51% nausea
23/27 water samples contained various amounts of Cryptosporidium
Due to failure of communication between Park and Researchers, they were unable to test animal stool samples
Recirculation of contaminated water Poor filtration and disinfection Also, nearly all the children did not show
symptoms until 2-6 days following visit. Due to incubation time, children could easily
affect any family members or friends without knowing. i.e. Swimming Pools
Adventure park was in a rural area Residential pools are more likely to be
outside of the city, in more rural and suburban areas.
People in rural areas are more likely to have contact with animal feces, farms
Rural parts are more likely to be affected with Cryptosporidium
Potentially lethal infectious disease Caused by bacteria, attacks the lungs Spread through air when people with an
active infections sneeze, cough, or transmit saliva through air
Most infections are asymptomatic and are latent
1 in 10 will progress to active disease and >50% will die if left untreated
Was the biggest killer in UK in 19th century
http://en.wikipedia.org/wiki/File:Tuberculos
is_symptoms.svg
2005, TB cases rose 10.8% from previous year in England
London recorded 3,479 cases, up from 3,129 in 2004
The highest proportion of cases - 38% - were reported among people from an Indian, Pakistani and Bangladeshi ethnic background.
Levels of TB in the UK-born population have remained stable
Foreign born population accounted for 5,310 cases in England in 2005
However on 22% arrived in England in past 2 years
This suggests a combination of:
Latent infections
New infections acquired from infected person in England
Travel to other countries where TB is common
Extremely high amounts of TB in countries a foreign-born UK citizen would travel too.
India, Bangladesh, Many African countries as well
WHO: South East Asia accounts for 35% of World’s TB rate
WHO: Africa accounts for 30% of World’s TB rate
According to 2001 UK Census:
1,053,411 Britons had full Indian ethnicity.
99.3% resided in England
491,300 resided in London
1,148,738 Britons categorized themselves as Black British
1,100,000 resided in London
This means that the chances of someone from England traveling to a region where TB is prevalent is extremely high
Many of foreign born people are living in urban-London, making the urban region extremely susceptible to TB
Prevention and education for those traveling to high TB areas is key
Questions?