Kelley Donham 2009 Zoonotic Risks of Agricultural Occupations Julie Smith, DVM, PhD, University of Vermont Extension Dairy Specialist Used by permission of: Kelley J. Donham MS, DVM, DACVPM Department of Occupational and Environmental Health College of Public Health, University of Iowa Danelle Bickett-Weddle, DVM, MPH, PhD, DACVPM Associate Director, Center for Food Security & Public Health, Iowa State University Principles and examples
Julie Smith, DVM, PhD, University of Vermont Extension Dairy Specialist
Used by permission of: Kelley J. Donham MS, DVM, DACVPM
Department of Occupational and Environmental Health College of Public Health, University of Iowa Danelle Bickett-Weddle, DVM, MPH, PhD, DACVPM
Associate Director, Center for Food Security & Public Health, Iowa State University
Principles and examples
Presenter
Presentation Notes
I appreciate the invitation to present this session of the Ag Medicine course and am really pleased with the range of expertise represented by the participants. I look forward to sharing information and perspectives with you over the next hour and a half. To try to right size your expectations, I want you to know I do not consider myself a zoonotic disease expert but as a veterinarian I have some insight as to which diseases of animals may pose problems for people. For over 10 years my outreach programs have focused on on-farm biosecurity – preventive health practices - to prevent endemic diseases of cattle such as Johne’s disease and emergency diseases that do not currently exist in this country like foot-and-mouth disease. I was surprised to find FMD listed in the assigned text as a zoonotic disease because it is not considered a public health threat. The caveat is that a few people with direct exposure to infected animals have been diagnosed with FMD, illustrating one of the points of this session which is to emphasize that evaluation of exposure risk is important in identifying zoonotic diseases when they occur in people. I do have some personal experience with zoonotic diseases. After graduating from vet school, I joined a mixed practice serving small and large animals in upstate New York where I had a personal run in with a zoonotic dz in the form of a rabid kitten. My experience as a graduate student provided additional exposure to zoonotic diseases. Several student employees experienced cryptosporidiosis and a grad student colleague experienced a severe undiagnosed enteric disease when the calves on his study had been diagnosed with Salmonella. In a moment I will be asking about your experiences with zoonotic diseases but first I want to credit Drs. Donham and Bickett-Weddle for the framework of this presentation and for selecting the diseases to be discussed. Modifying the presentation for effectiveness in this setting is a work in progress and your comments would be appreciated. In the first part of the presentation we will develop a better understanding of zoonotic diseases and how to assess and reduce risk of exposure. In the second part of the presentation we will take a closer look at 7 of the diseases listed on the syllabus with passing mention of tetanus. I have built in times for your input or questions but feel free to type questions or comments into the chat box as we go. Jean will alert me to any urgent issues or questions that need brought to my attention. I thank Lucy for her assistance in facilitating this webinar. Kelley Donham, MS, DVM, DACVPM, Professor and Associate Head for Agricultural Medicine, Department of Occupational & Environmental Health, University of Iowa College of Public Health, Iowa Center for Agricultural Safety and Health (I-CASH) Director, and Great Plains Center for Agricultural Health Deputy Director. Danelle Bickett-Weddle, DVM, MPH, PhD, DACVPM, Associate Director for the Center for Food Security and Public Health (since 2004). In that role, Dr. Bickett-Weddle manages development of materials for the USDA-APHIS National Veterinary Accreditation Program, co-leads the Secure Milk Supply Plan, and manages CFSPH's Infection Control and Biological Risk Management materials. She has teaching responsibilities in the College of Veterinary Medicine at ISU as well as the College of Public Health at the University of Iowa. She has been invited to give presentations throughout the U.S. and Mexico about disease prevention, agroterrorism, and biological risk management issues.
Kelley Donham 2009
What is your experience with zoonotic diseases?
Kelley Donham 2009
How do you say it? 1. Zoonosis
(a) zō-ˈä-nə-səs
(b) zō-ə-ˈnō-səs 2. Zoonoses
(a) zō-ˈä-nə-ˌsēz
(b) zō-ə-ˈnō-ˌsēz 3. Zoonotic
ˌzō-ə-ˈnä-tik
Presenter
Presentation Notes
It happens all the time in the English language that words aren’t pronounced the way they look, maybe more so in medicine where proper names are used in place of disease descriptions. For instance in veterinary medicine, Johne’s disease is a fairly common disease of cattle. What letter does Johne’s start with? The more we can interact during this class the better. Use the chat box. Use the raise hand function. Use the polling responses when available. Lucy will help me keep up. Before we get into today’s topic I want to make sure we are on the same page in terms of pronouncing some key words. For the word marked #1 on the screen, would you select your preferred pronunciation, a or b? And for the word marked #2 on the screen, would you select your preferred pronunciation? The third word only had one pronunciation provided in the dictionary.
Kelley Donham 2009
Overview What are zoonoses? Who is at risk? How are zoonoses transmitted? How can workers protect themselves? A few examples Wrap up Quickie quiz
Kelley Donham 2009
Zoonoses are diseases common to animals and humans. There are over 200 zoonoses in the world.
About 40 are risks for agricultural workers in the US.
Presenter
Presentation Notes
Zoonoses are diseases common to animals and humans. This is the most non-restrictive definition that includes such things as tetanus and histoplasmosis that infect both people and animals but are not transmitted from one to the other. They can be acute or chronic; unnoticeably mild or deadly in severity. There are over 200 zoonoses in the world. About 80 zoonoses occur in industrialized countries. About 40 are known risks for agricultural workers in the US – but that is not to say an agricultural worker could be exposed to all 40 – it depends on the ag sector and type of work, etc. Over half (60%) of known human pathogens are zoonotic; about ¾ (75%) of emerging diseases are zoonotic; Important not just as sporadic or epidemic diseases, but as potential bioterror weapons. Costly to control, conduct surveillance, treat
Kelley Donham 2009
Names can be deceiving! Common
Term Human Animal
Dysentery Shigella spp. Brachyspira (swine)
Typhoid S. typhi S. gallinarum Erysipelas Str.
pyogenes Erysipelothrix
Measles Host-specific virus
Taenia saginata
Presenter
Presentation Notes
Just because the same disease name is used for a disease in humans and a disease in animals doesn’t mean they’re the same thing! Brachyspira is a spirochete that became known as Seruplina when I was in vet school and was known as Treponema prior to that. Taenia saginata is a tape worm with adult phase in humans, and intermediate cysticercus in beef muscle or heart – beef measles
Kelley Donham 2009
People (zooanthroponosis)
Vertebrate animal (anthropozoonosis)
Either (amphixenosis)
Zoonoses can be classified by major reservoir.
Presenter
Presentation Notes
Need some new vocabulary words to impress your friends at a party? If the natural host is human, it’s a Zooanthroponosis (human to animal) M. tuberculosis If the natural host is a non-human vertebrate animal, it’s an Anthropozoonosis (vertebrate to human) leptospirosis If humans and other vertebrates both serve as natural hosts, it’s an Amphixenosis: (certain strains of Salmonella, Streptococcus, E. coli)
Kelley Donham 2009
Who is at risk for zoonotic diseases?
occupational recreational Photo by Julie Smith
Presenter
Presentation Notes
The risk of contracting a zoonotic disease depends on activities that bring humans into close association with animals or environment: These can be broadly classed as occupational and recreational activities. Preventing zoonoses, like other diseases, involves risk management. The risk assessment process involves identifying the risk or risks, then understanding and applying ways to mitigate the risk. Communicating about risks and ways to reduce exposure or take action if affected is all part of risk communication. I want you to become informed risk communicators about agricultural zoonoses.
Kelley Donham 2009
How many Vermonters have exposure to livestock?
7000 farms
50% of operators full-time
140,000 cows 10,000 beef cows
14,000 sheep
2700 pigs + hobby farms
Few large production units; many backyard
flocks
Livestock census (USDA NASS 2007)
Presenter
Presentation Notes
By way of background about livestock and poultry in Vermont, some figures from the last census of agriculture are presented here. (The 2012 census is currently underway.) When you account for the fact that there are less than 1000 dairy farms in the state, you realize that a lot of livestock farms have some other type of animals. Only half of the operators are full-time so significant number of people who work with farm animals also have another job. And a significant number of employees are part-time. And then you add in students who work at university farms with dairy or other animals and people who visits farms open to the public and you have an even greater number of people with potential exposure to diseases carried by animals or their environments that can be public health threats. Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, 2011, National Association of State Public Health Veterinarians.
Kelley Donham 2009
What populations are at greatest risk?
Kelley Donham 2009
Populations at greatest risk . . .
Presenter
Presentation Notes
Farmers and farm employees Veterinarians Processing plant workers Hair and hide plant workers Pet owners Rural residents or those who enjoy the great outdoors Fair and field day exhibitors and attendees\ Who else? Did you hear about the outbreak of anthrax associated with African drumming? Dec 2009 New Hampshire
Kelley Donham 2009
Vulnerable Populations: • Children
• Lower immunity • Women
• Abortion risk for Brucella, Q Fever, Listeria
• Those lacking “herd immunity”
Presenter
Presentation Notes
Agriculture is the only industry that can legally employ individuals as young as 12 years old.
This section of the course covers several important zoonoses. As medical practitioners or risk managers in a state with rural and agricultural activities and occupations, you should be aware of what these look like when presented in a clinical setting and understand their animal and environmental sources to help rule them in or out in appropriate situations. Certain activities will put people at greater risk of exposure to zoonoses: vaccinations, treating sick animals, handling carcasses, delivering newborns, etc. Working (or playing) outdoors increases potential exposure to zoonoses through exposure to ticks, mosquitoes, untreated water, and so on. Associating diseases with specific species can be helpful, but don’t get locked into tunnel vision. For instance, rabies, while listed under beef cattle, could just as well be listed under any other mammal- dog, cat, you name it. My own rabies exposure was from a kitten.
As was noted earlier, about ¾ of emerging diseases are found to be zoonotic. Here are a few that you are probably already familiar with. Deer tick from http://www.tickinfo.com/deertick.htm Mosquito from http://www.michigan.gov/deq/0,4561,7-135-3313_46123_24554-68318--,00.html Crow from http://en.wikipedia.org/wiki/File:Corvus_brachyrhynchos_30196.JPG Deer mouse from http://www.google.com/imgres?imgurl=http://www.dirkspestmanagement.com/wp-content/uploads/2011/09/Deer-Mice.jpg&imgrefurl=http://www.dirkspestmanagement.com/pest-controll-topic/rodents&h=386&w=500&sz=52&tbnid=m0RHe6FoUQ0tWM:&tbnh=91&tbnw=118&zoom=1&usg=__At-1Cb830keJcuOtueD8DXuWxw0=&docid=rdt5M2AG_AJJ7M&hl=en&sa=X&ei=yGsVUYmZErTW0gGtvYGQCw&ved=0CEwQ9QEwCQ&dur=3677
Kelley Donham 2009
Humans are often dead end hosts for zoonoses.
Lyme disease
West Nile fever
Bovine Spongiform Encephalopathy
Hanta virus
Presenter
Presentation Notes
Humans are dead end hosts for Lyme, WNV, BSE, Hanta, and usually Avian Influenza Deer tick from http://www.tickinfo.com/deertick.htm Mosquito from http://www.michigan.gov/deq/0,4561,7-135-3313_46123_24554-68318--,00.html Crow from http://en.wikipedia.org/wiki/File:Corvus_brachyrhynchos_30196.JPG Deer mouse from http://www.google.com/imgres?imgurl=http://www.dirkspestmanagement.com/wp-content/uploads/2011/09/Deer-Mice.jpg&imgrefurl=http://www.dirkspestmanagement.com/pest-controll-topic/rodents&h=386&w=500&sz=52&tbnid=m0RHe6FoUQ0tWM:&tbnh=91&tbnw=118&zoom=1&usg=__At-1Cb830keJcuOtueD8DXuWxw0=&docid=rdt5M2AG_AJJ7M&hl=en&sa=X&ei=yGsVUYmZErTW0gGtvYGQCw&ved=0CEwQ9QEwCQ&dur=3677
Kelley Donham 2009
An emerging swine zoonosis
Hepatitis E A human disease of concern primarily to
pregnant women There is a Hepatitis E virus of swine that can
be isolated from the feces of infected swine It can also be found in the environment in
such places as surface waters The importance of this disease and the risk
of transmission from swine is not yet known
Kelley Donham 2009
Another emerging swine zoonosis
Nipah Virus In the spring of 1999, 100 rural persons
died in a period of 4-5 days in Malaysia The virus thought to cause the disease is
called Nipah virus The virus is transmitted through urine to
humans The true importance of the disease is not
known at this time
Kelley Donham 2009
How often are zoonoses identified?
• Often they are not diagnosed • Sporadic rather than epidemic • Are maintained by aymptomatic carrier
animals • Someone has to know to ask the right
questions
Presenter
Presentation Notes
Just because these diseases have been described doesn’t mean they are easily identifiable. Accurate statistics on incidence don’t exist. They can be quite challenging to diagnose. Often cause non-specific symptoms May resemble severe influenza Their source can be difficult to identify. Livestock are often inapparent subclinical carriers. Nonspecific symptoms, lack of physician awareness, lack of diagnostic support may lead to non or mis-diagnosis. Another problem with diagnosis or risk management is that the same name is used for diseases caused by different organisms in people and animals
Kelley Donham 2009
How are diseases transmitted? Inhalation Ingestion Direct contact Animal-inflicted trauma Vector-borne Iatrogenic
Presenter
Presentation Notes
What’s another one we might add to this list? Nosocomial?
Kelley Donham 2009
Diseases transmitted by: Ingestion
Many dairy farm owners and employees consume raw milk Vermont dairies can sell up to up to 160 quarts per day (2-tiered system since 2009)
Presenter
Presentation Notes
For several decades the law allowed the sale of 25 quarts of raw milk to be sold at the farm In 2008 this was raised to 50 quarts In 2009 this was raised to160 quarts and allowed for delivery; but added some requirements, accountability and created a two tiered system In 2011 the allowable sales were changed from strictly fluid milk to fluid milk for personal consumption. Must be from healthy animals that are subject to veterinarian care and have current Rabies vaccinations, TB tests and Brucellosis tests, potable water tests (q 3 yr) Sell, barter, or give away Register with state if over 50 qt per day
Kelley Donham 2009
Diseases transmitted by: Bacteria found in unpasteurized milk: Listeria monocytogenes Salmonella spp. Campylobacter jejuni Yersinia enterocolitica E. coli O157:H7, Shiga-toxin E. coli
Other potential bacterial contaminants: Brucella (Bang’s), Mycobacteria,
Staphylococcus, Coxiella (Q fever)
Presenter
Presentation Notes
2007 National Animal Health Monitoring Survey (Dairy) found 28% of farms tested positive for Salmonella by PCR of either bulk tank milk or milk filters 7% tested positive for Listeria and 77% tested positive for Coxiella. >90% of dairies had at least one cow testing positive by fecal PCR for Campylobacter, with ~1/3 of healthy cows testing positive.
Kelley Donham 2009
Diseases transmitted by: Fecal-oral route Hand-washing facilities limited Abundant exposure to manure Salmonella, E. coli, Cryptosporidia, etc. Diarrhea, nausea, vomiting Abdominal pain and cramping Dehydration, fever
Kelley Donham 2009
Diseases transmitted by: Direct contact Ag workers rarely wear PPE MRSA, contagious ecthyma (orf),
dematophytosis, erysipeloid
Presenter
Presentation Notes
PPE = personal protective equipment
Kelley Donham 2009
Diseases transmitted by: Bite wounds or wound infections Rabies, Tetanus, other bacteria
Presenter
Presentation Notes
Rabies is deadly in those without prophylactic vaccination (most veterinarians and some other health professionals) or post-exposure prophylaxis (series of vaccines). Tetanus is deadly in those without prophylactic vaccination (nearly everyone covered when young) or post-wound antitoxin administration when toxoid not adequately boosted. CDC recommends booster every ten years. Tetanus is also a problem in intravenous drug users. States reporting most cases (2001 – 2008) were CA, FL, TX, NY and PA. Hispanics at same risk when IDUs excluded.
Kelley Donham 2009
What steps can workers take to protect themselves?
Kelley Donham 2009
Steps workers can take to protect themselves. Understand the risks Use appropriate PPE Wash hands Change clothes Stay up-to-date with vaccines like
tetanus and flu (rabies, in some cases)
Presenter
Presentation Notes
Vaccination of animals also helpful for rabies and lepto prevention
Rabies (hydrophobia) Drooling Convulsions, Excitability Exaggerated sensation at the bite site Loss of feeling in an area of the body Loss of muscle function Low-grade fever (102 F or lower) Muscle spasms, Numbness and tingling Pain at the site of the bite Swallowing difficulty (drinking causes spasms of
the voicebox)
Presenter
Presentation Notes
Disease has been recognized for over 4000 years. Preventable viral disease of zoonotic concern.
Viral amplification in brain, spinal cord Destroyed by disinfectants, UV light, heat Viable in carcass less than 24 hours
Longer if refrigerated Does not survive in dried saliva
Center for Food Security and Public Health Iowa State
University 2009
Presenter
Presentation Notes
Rabies is a Lyssavirus in the family Rhabdoviridae.
Kelley Donham 2009
Rabies worldwide (2013)
Presenter
Presentation Notes
Worldwide Endemic in Africa and Asia 40,000-60,000 deaths annually from rabies with 90% occurring in Asia 25,000 in India alone! 30-60% occur in children under 15 years of age Majority (worldwide) related to dog bites this disease can be brought home, especially from areas where vaccination of dogs/cats not widespread A few countries free of rabies Antarctica, Australia, Bahamas, Bermuda, Finland, Greece, Hong Kong, Iceland, Japan, New Zealand, St. Kitts, Singapore, Sweden, United Kingdom. Canine vaccination and rabies surveillance have been most effective in controlling rabies. Decreased rabies cases (canine and human) 90% in South America in last 20 years. WHO exercises copyright over its information to make sure that it is used in accordance with the Organization's principles. Extracts of WHO information can be used for private study or for educational purposes without permission. Wider use requires permission to be obtained from WHO.
Kelley Donham 2009
Blanton, et al. 2011 JAVMA: 239 (6) 773-783
Distribution of major rabies virus variants by reservoir animals, US and Puerto Rico, 2010
Presenter
Presentation Notes
Monoclonal antibody and gene-sequencing techniques have revealed antigenic differences among various isolates from major wildlife hosts within a given geographic region. Multiple variants of the virus, maintained in primary reservoir species in a given location. http://www.cdc.gov/rabies/exposure/animals/wildlife_reservoirs.html
Kelley Donham 2009
Blanton, et al. 2011 JAVMA: 239 (6) 773-783
Reported cases of rabies in raccoons by county, 2010
Kelley Donham 2009
Blanton, et al. 2011 JAVMA: 239 (6) 773-783
Reported cases of rabies in bats by county, 2010
Kelley Donham 2009
Rabies in cattle
Separation from herd, aggression Bellowing, hypersalivation, seizures Anorexia Pharyngeal paralysis often mistaken
for “choke”, resulting in human exposure
Progressive paralysis, beginning with hindquarters
Kelley Donham 2009
Rabies in Vermont 71 confirmed animal cases in 2009,
7 were cows or calves, 1 horse 63 confirmed animal cases in 2012,
1 cow and 1 sheep Most cases skunks and raccoons, also
bats and a few cats
Kelley Donham 2009
Rabies in Vermont 56 confirmed animal cases in 2014,
1 cat, 2 bobcats 50 confirmed animal cases in 2013,
1 cow, 1 calf, 1 horse, 1 cat, 1 dog Most cases skunks and raccoons, also
a few foxes and bats
Presenter
Presentation Notes
Big brown bat "Big brown bat" by NPS - http://www.nps.gov/sagu/naturescience/insectivorous-bats.htm ([http://www.webcitation.org/5iafk8bIg Archive link). Licensed under Public Domain via Commons - https://commons.wikimedia.org/wiki/File:Big_brown_bat.jpg#/media/File:Big_brown_bat.jpg
Kelley Donham 2009
How can workers avoid infection with rabies?
Presenter
Presentation Notes
Vaccinate farm cats, dogs, livestock, especially if going to fairs Don’t stick bare hand/arm into mouth of animal Get care for bites, scratches
Kelley Donham 2009
Rabies questions? 1-800-640-4374 (Vermont only) or 802-863-7240
Dr. Bob Johnson, State Public Health Veterinarian Monday through Friday, 8:00 a.m. to 4:30 p.m. Health Care Providers may contact Dr. Johnson 24/7 as needed.
The Department of Health is also responsible for the management of animals that may have exposed humans, assesses human and animal rabies exposure, coordinates rabies specimen testing and provides vaccination guidelines.
Rabies Hotline 1-800-472-2437 (800-4-RABIES) or 1-802-223-8697
Presenter
Presentation Notes
People are advised to avoid any animal that exhibits strange behavior, and not to try and trap or capture the animal themselves, but instead to call the state’s Rabies Hotline at 1-800-472-2437 (800-4-RABIES) or 1-802-223-8697. If bitten, wash the wound and call local health department or physician.
Worldwide distribution in domestic livestock and wild animals
Spirochete bacteria, often present in surface water
Presenter
Presentation Notes
Leptospira interrogans Rare in continental US; highest number of cases in Hawaii
Kelley Donham 2009
Presenter
Presentation Notes
100 to 200 cases identified in US annually, but disease is not reportable. 50% of known cases in Hawaii. Considered one of the more widespread zoonotic diseases in the world, with greatest incidence in temperate and tropical areas (recent significant increases in prevalence in Peru, Ecuador, and Thailand). Occupational or recreational exposure, incidence often increases in response to episodes of flooding. One of the recent larger outbreaks in continental US resulted in 110 cases in a group of 775 exposed persons who participated in triathlons, which included swimming in a lake, in June and July of 1998. Hosts: Cattle, pigs, dogs, various wild animals Incubation period: 3 to 14 or 21 days.
streams and ponds Mechanism of transmission: Direct or
indirect contact with urine from infected animals, or handling an aborted fetus
Route of entry: Mucous membranes Time/season:
Mid to late summer
Kelley Donham 2009
Symptoms
Usually asymptomatic Range of symptoms: high fever,
severe headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, rash
Severe, acute, icteric form with liver and kidney damage: Weil’s disease
Presenter
Presentation Notes
Symptoms of Weil’s disease in humans: Many cases are asymptomatic. Symptoms include high fever, severe headache, chills, muscle aches, and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhea, or a rash (from CDC.gov). If untreated, disease may progress to kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress may result. In animals, chronic kidney infections and abortions may be seen
Kelley Donham 2009
How can workers avoid infection with leptospirosis?
Presenter
Presentation Notes
Vaccination widely practiced in veterinary settings Caution in handling tissues (aborted fetuses, placentas) Controlling wildlife access
Kelley Donham 2009
Influenza Virus
Center for Food Security and Public Health Iowa State University 2007
Family Orthomyxoviridae “myxo” means mucus
Three main types Type A Multiple species
Type B Humans
Type C Humans and swine
Presenter
Presentation Notes
Influenza viruses belong to the family Orthomyxoviridae. They are classified into three main types. Influenza type A viruses affect multiple species including humans. Influenza types B and C both infect humans, but type C is also known to infect swine. We will discuss each of these further in the next few slides. (Photo: ISU-FAD course section by Dr. Corrie Brown)
Kelley Donham 2009
Influenza A is the principal zoonotic strain Infects multiple species Humans, pigs, birds, horses, others
Most virulent group Classification by surface antigens
into subtypes
Center for Food Security and Public Health Iowa State University 2007
Presenter
Presentation Notes
Disease from highly pathogenic avian influenza is also known as fowl plague, fowl pest, peste aviaire, geflugelpest, typhus exudatious gallinarium, Brunswick bird plague, Brunswick disease, fowl disease, fowl or bird grippe. Influenza type A infects multiple species. Several human influenza strains are type A while all avian strains are type A. They are considered the most virulent group, although not all strains cause clinical disease. Type A influenza viruses are classified into subtypes based on two surface antigens
Kelley Donham 2009
Influenza A
Center for Food Security and Public Health Iowa State University 2007
Presenter
Presentation Notes
Here are the major antigenic components of the influenza A virus: hemagglutinin (H) and neuraminidase (N), sometimes also referred to as HA and NA respectively. The yellow bars represent the hemagglutinin (HA) part of the virus. The pink protrusions represent neuraminidase (NA). The virus is composed of eight segments of RNA. Having segments makes it easier for reassortment to occur.
Kelley Donham 2009
Center for Food Security and Public Health Iowa State
University 2007
Presenter
Presentation Notes
Here are the major antigenic components of the influenza A virus: hemagglutinin (H) and neuraminidase (N), sometimes also referred to as HA and NA respectively. The yellow bars represent the hemagglutinin (HA) part of the virus. The pink protrusions represent neuraminidase (NA). The virus is composed of eight segments of RNA. Having segments makes it easier for reassortment to occur.
Kelley Donham 2009
Interspecies transmission
Presenter
Presentation Notes
This diagram depicts the interspecies transmission of influenza A viruses and is adapted from Fields Virology, 4th edition. The red arrows are direct transmissions that have occurred and caused disease. Influenza A viruses seem to be able to cross species barriers if given the right opportunity. The center of all this is the wild waterfowl, the reservoir species. Influenza A has caused disease in seals and whales (separate outbreaks with different viruses). The viruses appeared to have been transmitted from wild waterfowl. Equine influenza may have origins from wild waterfowl also. The virus has adapted to the equine host and circulates in that population. The H3N8 of US equine appears to have been transmitted to dogs in January of 2004. This virus has apparently adapted to its new host. In the summer of 2005 it was spread between dogs across the US. It was most prominent in racing dogs but there were cases in pet dogs also. It remains to be determined if the virus will continue to circulate in this species. Wild waterfowl are often responsible for transmission of the virus to domestic poultry. The HPAI H5N1 Asian influenza virus infected cats. Zoo cats fed infected uncooked poultry meat became infected and some domestic pet cats that were feeding on a pile of infected dead chickens became infected. The virus did not spread in cats outside of those two outbreaks. The “mixing vessel” pig can be infected by influenza viruses from wild waterfowl, humans, and domestic poultry. Influenza from swine has been transmitted to humans and caused disease. Human influenza virus has infected pigs. Some of the swine influenza viruses circulating and causing disease in the US swine population contain human influenza genes. Influenza virus from domestic poultry has sporadically infected and caused severe disease in humans, especially highly pathogenic strains. The first documented case of influenza transmitting directly from bird to human was in 1997. This is discussed later in the presentation. There have been no reports of direct transmission to human from wild waterfowl reservoir hosts. Adapted from Fields Virology, 4th edition, Lippincott Williams & Wilkins, page 1538
Kelley Donham 2009
Novel H1N1 of 2009 aka “Swine Flu”
Kelley Donham 2009
Kelley Donham 2009
Presenter
Presentation Notes
6 – 8 month delay between antigen selection and vaccine availability All of the 2014-2015 influenza vaccine protected against the following three viruses: an A/California/7/2009 (H1N1)pdm09-like virus an A/Texas/50/2012 (H3N2)-like virus a B/Massachusetts/2/2012-like virus. Some of the 2014-2015 flu vaccine also protected against an additional B virus (B/Brisbane/60/2008-like virus). Influenza A strains can circulate among several species; Influenza B circulates primarily among humans Influenza A can affect humans, ducks, chickens, pigs, horses, whales and seals
Kelley Donham 2009
Epidemiological aspects of swine influenza Swine influenza describes important respiratory
pathogen of pigs Type A, H1N1, H1N2 and H3N2 circulate in pigs Component of “porcine respiratory disease complex” Seasonal pattern overlaps with human influenza
As host to both avian and human strains, as well as swine strains, pigs can serve as “reassortment vessels”
Pigs CAN contract influenza from humans and humans from people (relatively close contact required)
Kelley Donham 2009
Epidemiological aspects of avian influenza Wild birds are the natural reservoir of all
subtypes of influenza A viruses Most infections subclinical in birds Highly pathogenic strains (e.g., H5 or H7) can cause
serious disease (death) in wild and domestic birds 2014-2015 US Avian Influenza outbreak
H5N2 and H5N8 (also found in captive falcons) 12/19/2014 – 6/17/2015 48 million birds affected Many turkeys flocks, also pullets and laying hens
This influenza subtype considered a low risk to public health BUT CAUTION IS WARRANTED
Kelley Donham 2009
How can workers avoid infection with zoonotic influenza?
MSRA: resistant to penicillins and related beta-lactam antibiotics, cephalosporins Modified penicillin-binding protein (PBP2a)
First reported as nosocomial pathogens
Rising prevalence, now considered “community associated”
Presenter
Presentation Notes
1.5% of US human population estimated to be colonized with MRSA (vs. about 30% colonized with SA). In 2005, estimated to cause 94,000 infections and over 18,000 deaths in US (Klevens, et al., 2007, JAMA 298:1763)
Kelley Donham 2009
Genetics of MRSA
PBP2a is encoded by mec2 gene Carried by one of six Staphylococcus
chromosomal cassettes (SCCs) SCCs may carry genes for multiple
antibiotic resistance as well as for Panton-Valentine leucocidin (PVL)
Presenter
Presentation Notes
Modified penicillin-binding protein (PBP2a) is encoded by mec2 gene, carried by one of six chromosomal cassettes PVL is a cytotoxin and is the cause of necrotic lesions involving the skin or mucosa, including necrotic hemorrhagic pneumonia. PVL creates pores in the membranes of infected cells. PVL is produced from the genetic material of a bacteriophage that infects Staph aureus, making it more virulent.
Kelley Donham 2009
Transmission of MSRA between humans and animals Companion animals tend to carry
human-associated MRSA strains “humanosis”
Strains associated with livestock 1972, Belgian milk cows Multiple reports since in pigs, sheep,
chickens, rabbits, horses, cattle As in humans, often associated with
poor skin condition
www.thebellamossfoundation
Kelley Donham 2009
MRSA in swine Isolates found to be shared between
swine and human caretakers ST398 transmitted from pigs to pig farmers
in Netherlands Recent report estimates 70% prevalence
in one Iowa swine unit while a 2nd unit in Illinois had no positive samples
Prevalence in sampled workers 64% at farm with colonized swine
Presenter
Presentation Notes
ST398 accounts for about 20% of all MRSA found in the Netherlands; prevalence in pig farmers estimated to be about 760 times that of general population.
Kelley Donham 2009
MRSA in cattle Reported MRSA isolated from cows
with subclinical mastitis 27 of 375 SA isolated were MRSA Throat sampling of 12 workers on
farm found 1 MRSA Human strain indistinguishable from
that isolated from several cows Direction of transfer not established
Juhász-Kaszanyitzky, et al. EID 2007: 13(4) 630-632
Presenter
Presentation Notes
MRSA could NOT be detected in a nationally representative sample of bulk tank milk from U.S. dairy farms (NAHMS, 2007).
Kelley Donham 2009
How can workers avoid infection with MRSA?
Presenter
Presentation Notes
Wear gloves!
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Erysipelas: “Diamond Skin Disease”
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Erysipelas / Erysipeloid
Erysipelothrix rhusiopathiae Relatively common pathogen of swine,
poultry (turkeys), fish Commercial herds vaccinate or exclude Survives well in environment: soil, fecal
material, world-wide distribution Erysipeloid in humans
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Infection in people typically on hand or foot
Typically contracted by direct contact (occupational disease)
Swelling, painful No suppuration Violet-colored zone of
Direct contact Fomites Ingestion Arthropods (ticks) Person-to-person (rare)
Center for Food Security and Public Health Iowa State
University 2009
Presenter
Presentation Notes
Q fever can be transmitted via a variety of routes. Domestic ruminants represent the most frequent source of human C. burnetii infection. However, pets, (i.e., cats, dogs and rabbits) have also been involved as sources of urban outbreaks. Aerosolization is the primary mode of transmission in humans. Organisms can be found in airborne droplets or dust contaminated by placental tissues, birth fluids, or excreta of infected animals. Shedding of C. burnetii into the environment occurs mainly during parturition; over 109 bacteria per gram of placenta are released at the time of delivery. Aerosol or direct transmission can occur when infected animals are processed as meat, during necropsies or assisting deliveries. Due to the persistence of the organism in the environment, dried infective material can contaminate dust or soil, which can be carried considerable distances by wind and has been documented to travel downwind up to ½ mile or more. This has resulted in cases of patients without any evident contact with animals. Fomites (i.e., newborn animals, wool, bedding, clothing) can also be contaminated by such materials and serve as a source of the transmission. Organisms shed in urine and feces of infected animals can also serve as a source of water, dust, soil or fomite contamination. Water may be contaminated and act as a vehicle for dissemination. Shedding in the milk occurs due to infected mammary glands, but pasteurization kills this organism. C. burnetii has been naturally and experimentally isolated from a variety of arthropods, (mainly ticks but also cockroaches, beetles, flies, fleas, lice, mites). Over 40 tick species are naturally infected with C. burnetii, and transovarial (mother to offspring) and transstadial (between developmental life stages) transmission has been documented. Feces of infected arthropods can serve as a source of C. burnetii infection and can remain infective for at least 19 months. Animals typically acquire Q fever through exposure to other infected animals, either through direct contact with contaminated material or aerosol exposure.
Male dairy farmer, 46 years of age Sudden onset of fever, chills, cough,
weight loss Initially thought it was influenza Symptoms persisted for 2 weeks Presented to emergency room Again influenza was the diagnosis
Center for Food Security and Public Health Iowa State
University 2009
Presenter
Presentation Notes
In March 2001, a 46 year old male dairy farmer from Georgia reported a sudden onset of fever, chills, cough, and weight loss. A physician initially diagnosed influenza in the patient. Two weeks later the symptoms still persisted and the patient presented to the emergency room where he was again diagnosed with influenza.
Kelley Donham 2009
Case study (continued) Referral to infectious disease specialist Tested positive for Q fever Antibiotics for 5 days Resolved in 2 weeks
Epidemiology No recent births on his farm Two beef cattle herds across the road 2 out of 14 tested positive for Q fever
Center for Food Security and Public Health Iowa State
University 2009
Presenter
Presentation Notes
The emergency room doctor then referred the patient to an infectious disease specialist. The infectious disease specialist tested the patient for Q fever and he was positive. The patient took a five day course of gatifloxacin (a fluoroquinolone), and symptoms resolved within 2 weeks. Although the patient owned several dairy cows, no recent calvings had occurred at his farm. Two beef cattle herds (approximately 35 animals per herd) were pastured across the road from the patient’s farm. Fourteen animals from the neighboring beef herds were then tested; two animals were found to be positive for Q fever. MMWR October 18, 2002/51(41);924-927.
Kelley Donham 2009
Dairy survey
Center for Food Security and Public Health Iowa State
University 2009
EID April 2005 Evaluated bulk tank milk
samples for prevalence 3 year period 316 samples; 19 states (most northeast) >90% prevalence in bulk tank milk No human disease information
Presenter
Presentation Notes
A study published in the Emerging Infectious Diseases April 2005 journal looked at the prevalence of Coxiella burnetii in bulk tank milk samples in New York State and 18 other states. Samples collected Jan 2001 to Dec 2003. Trans-PCR (for transposon-like sequence) evaluated the prevalence of the organism…94.3% prevalent with no human disease information.
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Milk transmission questioned Epidemiology and Infection 2006 Reviewed literature establishing
pasteurization conditions effective against Coxiella burnetii and patterns of cases vs exposure
Presenter
Presentation Notes
Epidemiology and Infection 2006 raised the question of the importance of milk as a route of transmission and need to set pasteurization conditions to kill it. The authors conclude “it seems more than plausible that clinical disease of Q fever results only from inhalation of C. burnetii and sometimes arthropods bites. Ingestion of C. burnetii-contaminated milk or milk products may result in serological conversion potentially indicating infection but not necessarily clinical disease.”
Kelley Donham 2009
How can workers avoid infection with Q fever?
Presenter
Presentation Notes
PPE when delivering newborn small ruminants and cattle
Kelley Donham 2009
Small ruminants and human health concerns Coxiella Brucellosis (Brucella ovis and
Brucellosis, Leptospirosis, and Tuberculosis can not only affect small ruminants but can also infect humans who consume raw or contaminated milk or dairy products
Kelley Donham 2009
Small ruminants and human health concerns: Brucellosis Brucellosis (Brucella ovis and
melitensis) Gram negative bacteria Transmitted in placenta, fetus, fetal
membranes, semen, milk Consider if abortions and stillbirths seen Rev-1 B. melitensis vaccine can cause
disease in people
Presenter
Presentation Notes
Especially problematic in developing nations
Kelley Donham 2009
Small ruminants and human health concerns: Chlamydiosis Chlamydiosis (C. abortus) Considered Gram negative but difficult to
stain Transmitted by ingestion, aerosols,
direct contact with mucous membranes Consider if abortions and stillbirths seen Recovered animals immune (or don’t
abort) for several years
Presenter
Presentation Notes
Transmitted in placenta and uterine discharges, and goat milk Related chlamydia carried by psitticine birds (parrots, macaws, parakeets, budgies) – psittacosis Related chlamydia carried by cats may cause conjunctivitis
Kelley Donham 2009
Small ruminants and human health concerns: Toxoplasmosis Toxoplasmosis (Toxoplasma gondii) Intracellular protozoan parasite Life cycle: oocyst, tachyzoite, bradyzoite,
tissue cyst Animal (or human) becomes infected
when eats un- or under-cooked meat or tissues containing tissue cysts
Can cross placenta in sheep and goats Cats are the definitive host, generally
asymptomatic
Presenter
Presentation Notes
Worldwide, common in warm, humid climates, especially at lower altitudes Incubation period in humans is 10 to 23 days after ingesting contaminated meat or 5 to 20 days after exposure to infected cats
Kelley Donham 2009
Small ruminants and human health concerns: Vibriosis Vibriosis (Campylobacter spp.) Gram negative curved or spiral rods C. jejuni is predominant cause of sheep
abortion in US C. fetus also causes abortions, stillbirths,
weak lambs in sheep C. jejuni causes enteritis in humans;
C. fetus is opportunistic pathogen in humans, causes septicemia
Presenter
Presentation Notes
Guillain-Barre (Gee YAH buh RAY) syndrome may follow (1 in 1000 diagnosed infections); almost 1/3 of GBS cases
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What protective actions should people take?
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Steps workers can take to protect themselves. Understand the risks Use appropriate PPE Wash hands Change clothes Avoid needle sticks when vaccinating
animals for Brucella
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Wrap Up What is a zoonosis? A disease common to humans and
animals. We classify zoonoses by: Etiologic agent Associated human activity Groups of animals involved Direction of transmission
Kelley Donham 2009
Take home points General features of zoonoses: Vague symptoms, may evade diagnosis Often resolve spontaneously, seldom
fatal Animals are often subclinically infected
(appear “healthy”) Humans often an incidental host
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Take home points Prevention worth a pound of cure Risk communication Risk management
Kelley Donham 2009
Now a quick quiz
Kelley Donham 2009
Zoonoses are diseases common to animals and humans.
1. True 2. False 3. Don’t know
1 2 3
0% 0%0%
Kelley Donham 2009
Zoonoses are easily recognized and diagnosed.
1. True 2. False 3. Don’t know
1 2 3
0% 0%0%
Kelley Donham 2009
Leptospirosis can only be contracted by direct contact of mucous membranes with urine.
1. True 2. False 3. Don’t know
1 2 3
0% 0%0%
Kelley Donham 2009
Rabies only affects wildlife in Vermont.
1. True 2. False 3. Don’t know
1 2 3
0% 0%0%
Kelley Donham 2009
A bull’s eye lesion is a sign of MRSA.
1. True 2. False 3. Don’t know
1 2 3
0% 0%0%
Kelley Donham 2009
Can a person be infected with the pathogen responsible for this animal’s skin problem?
