BRUCELLOSIS Sarah Jacobs And Jessica Sampson
Videos!! • http://www.youtube.com/watch?v=b45P4ut2K0Q • http://www.youtube.com/watch?v=rLfysIpGk_Y • http://www.youtube.com/watch?v=gRS4shfH1Pw
Microbiology • BacteriaBrucellaabortus • Gram- negative • Rod shaped • Blood-borne pathogen • Zoonotic • Killed by disinfectants and pasturization
Symptoms • ANIMALS: • aborted fetuses • weak offspring • low milk production • HUMANS: flu-like symptoms • Fever • Pain • Fatigue • Swollen glands
Transmission: How • HUMANS: • unpasteurized milk and cheese • Contact with infected materials • Aerosols and sexually • ANIMALS: • Infected meat • Contact with afterbirth • Aerosols and sexually
Transmission: Who • Mostly cattle and bison/buffalo • Humans • Rarely goats, elk, camels, pigs, and canines
Treatment • Test-and-slaughter technique • Two types of vaccinations • Antibiotics • Quarantine herds • Depopulate herds
A Major Problem • Yellowstone National Park is a major home for buffalo • In the past, buffalo and cattle shared grazing grounds • Farmers killed and ran buffalo back into YNP • Hunting of buffalo dwindled populations to near extinction • SO…..
Management • Government put hunting policies on buffalo to increase their population • Buffalo grazing land outside of YNP was expanded • Buffalo were quarantined, tested and vaccinated • Over $3.5 billion was spent on vaccinating cattle herds
CASE STUDY • Reproduction and Survival of Yellowstone Bison • Conservation of bison in YNP has lead to conflict regarding overabundance and potential transmission of brucellosis to cattle
Objectives • 1. Estimate pregnancy rates, birth rates, adult survival, and population growth rates in each bison herd. • 2) Evaluate what factors influenced these rates. • 3) Estimate a population growth rate (k) from these vital rates.
Methods • Captured adult female bison during October, February, and May 1995-1999. • Fit bison with radio collars equipped with motion-sensitive mortality sensors. • Aged the Bison using wear patterns in teeth. • Used telemetry homing techniques to monitor the survival of radio collared bison monthly during autumn 1995 through spring 2001.
Methods cont. • When a mortality signal was detected, they located the animal and evaluated cause of death. • They recaptured radio collared bison during early-term pregnancy (Oct), late-term pregnancy (Feb), and shortly after calving (Apr-May) during 1995- 2001. • They monitored bison daily during the calving season from mid-March through June. • They considered birth successful when a live calf in close association with the female was observed. They considered birth unsuccessful if they observed an aborted fetus, stillborn calf, or if they repeatedly failed to detect a calf associated with the female.
Results • 26 bison were captured from the northern herd • 27 bison from the central herd • They were monitored for 101 and 89 animal-years. • There were 15 deaths of marked bison during 1995-2001, excluding capture-related deaths and removals. • Five bison died from unknown causes, 4 from vehicle collisions, 3 from predation, 2 from winterkill, and 1 from injury.
Results cont. • They monitored birth rates of 48 females aged 23 years, which produced 96 live calves in 145 reproductive seasons. • Of these 145 records, 66 were from bison testing positive for brucellosis, whereas 69 records were from brucellosis-negative bison, and 10 records were from bison sero-converting that year. • These records included 15 from 3- year-old females, 82 records from 4-8 year olds, and 44 records from females >9 years.
Results cont. • There was considerable support for variation in birth rates between age classes. • These results suggested the growth rate of the population could increase approximately 29% if brucellosis were eliminated.
Discussion • As expected, 3 year olds had lower pregnancy and birth rates than did older individuals. However, they did not detect reduced survival in older animals (>9 yr) due to senescence. • 50-55% of bison in both herds have been exposed to brucellosis. • Brucellosis infections reduced birth rates in both age categories, although these effects were most prevalent in bison that were exposed to brucellosis that year (i.e., sero-converters) and effects seemed to wane thereafter.
Discussion cont. • Four radio collared bison began to test negative for brucellosis in years after having previously tested positive. • Brucellosis antibody levels in these animals may have decreased to a level below detectablity. • As expected, the relatively constant adult survival was the most elastic trait, and juvenile survival was highly variable year to year.
Management • Findings suggest that if vaccination plans are implemented and successful at substantially reducing or eradicating brucellosis, then population growth rates could increase approximately 29%. • Increased growth rates could contribute to more movement outside the park because bison respond to increased density through spatial responses . • Even without the threat of brucellosis transmission, such movements would exacerbate societal conflicts regarding overabundance and property damage. • Future research should focus on estimating juvenile survival because this rate is currently largely unknown, but it seems to have a relatively high effect on population growth.
Conclusion • There are no cases on record of bison transmitting Brucellosis to cattle • If brucellosis in bison is treated, their population could increase…..causing other economic implications • Populations of bison and cattle need to be continually monitored and managed • Is brucellosis transmission between bison and cattle really a concern?
Fun Facts • Brucellosis is one of the most easily acquired laboratory infections. • any bison who tests positive will be shipped to slaughterhouses and have their meat distributed to American Indian tribes and food banks. • In one study, coyotes were fed infected cattle placenta to test whether they would transmit it back to the cattle. • http://www.sodahead.com/united-states/should-the-bison-be-slaughtered/question-1497157/?link=ibaf&imgurl=http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/1024/bison-baby.jpg&q=bison%2Bbrucellosis%2Bmap
Sources • http://www.cfsph.iastate.edu/Factsheets/pdfs/brucellosis_abortus.pdf • http://0-www.jstor.org.catalog.lib.cmich.edu/openurl?volume=71&date=2007&spage=2365&issn=0022541X&issue=7 • http://0-onlinelibrary.wiley.com.catalog.lib.cmich.edu/doi/10.1111/j.1365-2664.2009.01633.x/pdf • http://www.libraryindex.com/pages/670/Endangered-Mammals-BISON.html • http://www.jwildlifedis.org/cgi/reprint/24/3/533.pdf • http://www.asm.org/images/pdf/Brucella101504.pdf • http://www.nps.gov/yell/naturescience/bisonqa.htm • http://www.uptodate.com/contents/microbiology-epidemiology-and-pathogenesis-of-brucella • http://www.reuters.com/article/2011/02/16/us-yellowstone-bison-idUSTRE71E0CI20110216 • http://www.youtube.com/watch?v=b45P4ut2K0Q • http://www.youtube.com/watch?v=rLfysIpGk_Y