May 4, 2018 8:30-9:30AM Transmission Routes for Zoonotic Pathogens—From the Common to Highly Hazardous
INDIANA UNIVERSITY BLOOMINGTON What is One Health?
INDIANA UNIVERSITY BLOOMINGTON Centers for Disease Control and Prevention Definition:
• “One Health recognizes that the health of people is connected to the health of animals and the environment.” • “Goal of One Health is to encourage the collaborative efforts of multiple disciplines-working locally, nationally, and globally-to achieve the best health for people, animals, and our environment.” • “One Health approach is important because 6 out of every 10 infectious diseases in humans are spread from animals.” • “Animals also share our susceptibility to some diseases and environmental hazards. Because of this, they can serve as early warning signs of potential human illness. ”
INDIANA UNIVERSITY BLOOMINGTON Some Zoonotic Diseases…
• Rabies • Salmonella infections • Zika virus • Q fever (Coxiella burnetti) • Toxoplasmosis • And many, many more! …are also Infectious Diseases of Public Health Significance (IDPHS)
INDIANA UNIVERSITY BLOOMINGTON There are a Number of Infectious Diseases of Public Health Significance
• Anthrax • Monkeypox • Avian Influenza (H5N1) • Plague • Botulism • Q Fever • Ebola (EVD) • Severe Acute Respiratory • Extensively Drug-Resistant Syndrome (SARS) Tuberculosis (XDR-TB) • Smallpox • Lassa Fever • Staphylococcal enterotoxin B • Marburg Virus (SEB) • Middle East Respiratory • Tularemia Syndrome Coronavirus (MERS-CoV) No title Image credit: Anonymous artist’s interpretation of infectious diseases from Pinterest World Health Organization list of diseases most likely to spark a public health emergency
http://www.who.int/blueprint/priority-diseases/en/ The Public Health Problem of Infectious Diseases • Biological Hazards • Emergency Preparedness and Response • Economic Implications • Safe Work Environments • Promote Health, Prevention Practice, Resiliency, and Financial Stability to communities Routes of Exposure
Guide on Preventing the Transmission of Infections
Biosafety and Infectious Disease Training Initiative Routes of Exposure cont.
• Contact • Droplet • Airborne • Vehicle • Vector borne Guide on Preventing the Transmission of Infections Infectious Agents Reservoirs (microorganisms) • Humans • Bacteria • Symptomatic or • Viruses asymptomatic • Fungi • Incubation periods • Parasites • Animals • Prions • Environment
Guide on Preventing the Transmission of Infections No title Portals of Entry
“A portal of entry is the route by which an infectious agent enters the host” • Mucous membranes of the respiratory tract • Gastrointestinal tract • Urinary tract • Breaks in the skin (e.g. wounds) • Devices such as intravenous lines
Guide on Preventing the Transmission of Infections Portals of Exit “Portals of exit are the routes by which an infectious agent (microorganism) leaves the reservoir (not all reservoirs have an obvious portal of exit e.g. the environment).” • Blood • Body fluids, excretions, secretions • Skin • Respiratory • Gastrointestinal • Mucous membranes
Guide on Preventing the Transmission of Infections Host Susceptibility “An individual must be susceptible to the infectious agent (microorganism) for an infection to occur. Humans do not become infected with most animal viruses because they do not have the appropriate cell receptors, and individuals with circulating antibodies to vaccine preventable diseases do not develop infection because the immune response prevents the infectious agent from multiplying.” Guide on Preventing the Transmission of Infections Avian & Swine Influenza
Image credit: CDC, 2015 Key Facts of Seasonal Influenza • Period of contagiousness: Most healthy adults can infect 1 day before symptoms and 5-7 days after becoming sick
• Experts say flu is primarily spread through droplets or contaminated surfaces
• Very difficult to distinguish from other viral or bacterial-caused respiratory illnesses
• 2018 season: H3N2 strain (Type A) • October 1, 2017 to February 17, 2018 • 21,279 laboratory confirmed flu-associated hospitalizations • 74.5 per 100,000 population • Final data TBD • Death rate higher this year in children & general public than in over a decade
(CDC, 2015)
(CDC, 2017, PHAC, 2014)
Avian Influenza Key Facts
• “Bird flu”, “Pandemic influenza”, “Influenza virus Type A” • Asian lineage strains: H7N9 and H5N1 have been responsible for most human illness worldwide (high pathogenic strains) • Rare cases of human infection with viruses, reported, but increased risk in agriculture
• Vectors: Wild birds • Host range: Natural in waterfowl, can be highly pathogenic when introduced to domestic poultry, viral transmission H5N1 to mammals (domestic cats, dogs, etc.) • Infectious dose: Unknown • Incubation Period: Average cluster 3-5 days • Risk Group 2 or 3, depending on specific virus (BSL-2 containment)
INDIANA UNIVERSITY BLOOMINGTON (CDC, 2017, PHAC, 2014)
Avian Influenza cont.
• Mode of Transmission: Direct transmission of virus from birds to humans (mucus membranes with infectious secretions or bird excreta) • Slaughtering, de-feathering or preparing sick poultry associated with transmission • Oral ingestion of contaminated water, fomites, poor hand hygiene lead to self- inoculation • Communicability: Limited human-to-human, bird-to-bird very common, bird-to-human • Signs & Symptoms: Range from conjunctivitis to influenza symptoms; can result in pneumonia, acute respiratory distress, multiple organ failure, etc. for those where complications arise • Treatment: Susceptible to neuraminidase inhibitors, oseltamivir, zanamivir, peramivir • Inactivation: 132-140F; can survive in lake water for 4 days, and feces of various temperatures and humidity
INDIANA UNIVERSITY BLOOMINGTON Swine Influenza
• Type A virus; main in U.S. pigs are H1N1, H3N2, H1N2
• 1918 pandemic was an H1N1 strain
• Also rare in humans but human infections have occurred due to variant viruses
• Humans exposed to infected pigs or environment contaminated with swine flu
• Concerning because pigs are susceptible to avian, human, and swine influenza viruses (multi-species), so it is possible for the genes of these viruses to mix and create new ones
• Similar symptoms, complications and modes of transmission (human-to- human) as regular influenza
• Same suggested treatment as avian influenza
(CDC, 2017; PHAC, 2015)
INDIANA UNIVERSITY BLOOMINGTON Zika Virus
Image credit: NPR Zika Overview
• Zika is spread mostly by the bite of an infected Aedes species mosquito (Ae. aegypti and Ae. albopictus) • These mosquitoes are aggressive daytime biters • They can also bite at night
• Zika can be passed from a pregnant woman to her fetus • Infection during pregnancy can cause certain birth defects
• Zika can also be sexually transmitted, through blood (includes infusions), and laboratory & healthcare settings
• There is no current FDA-approved vaccine or medicine for Zika
Cases 2016: 41,000 Zika cases in the U.S. (36,000 from American territories) 2017: 430 symptomatic cases in the U.S. reported (417 from travel)
(CDC, 2018) (NY Times, 2017) Concerning Effects (Based on 2016 data)
INDIANA UNIVERSITY BLOOMINGTON (One Health, B. Dunham, Center for Veterinary Medicine, 2017)
Zika Virus
• Exemplifies One Health:
• “…approach brings together entomologists, physicians, veterinarians, virologists, wild life biologists, environmental experts, universities, governments, public health organizations, world health organizations, just to mention a few… all seeking to help address the following needs: (1) infection control, (2) treatment development, (3) diagnostic tests”
• “Determining whether there are non-human reservoirs for Zika virus needs to be established; studying the viral strains may help explain why the virus has demonstrated the capacity to spread exponentially in the human population in the Americas”
• “Enhanced surveillance systems are needed; take advantage of apps via smartphones; collecting and analyzing data to assist with public health strategies”
INDIANA UNIVERSITY BLOOMINGTON (CDC, 2018) Zika Symptoms, Testing & Treatment
• Common Symptoms: Fever, rash, joint pain, conjunctivitis (red eyes), muscle pain, headache • Lasts several days to a week • Symptoms can be mild and indistinguishable from other body ailments, so person may not think to get tested
Testing: Remains in the blood of the infected for a week • Doctor or healthcare provider may order blood tests • Once a person has been infected, he or she is likely to be protected from future infections • CDC suspects it remains in other bodily fluids (i.e. seminal) for up to 6 months
• Treatment: No specific medicine or vaccine for Zika • Rest, fluids, pain relievers • Do not take aspirin or anti-steroidal
(CDC, 2016) Zika Cases Reported in U.S. as of March 2018
No title
Biosafety and Infectious Disease Training Initiative Zika Prevention: Mosquito Control
. Prevent mosquito bites
– Use insect repellent with active ingredients: DEET, Picaridin, para-menthane- diol, IR3535
– Reapply insect repellent as directed
– Effectiveness of non-EPA registered natural repellents unknown . Integrated Mosquito Management
– IMM is based on an understanding of mosquito biology, the mosquito life cycle, and the way mosquitoes spread viruses . Aerial Spraying
– Aerial treatment of areas with products that rapidly reduce both young and adult mosquitoes can help to limit the number of mosquitoes that carry the Zika virus
Biosafety and Infectious Disease Training Initiative (CDC, 2016) Q Fever (Coxiella burnetti)
Image credit: Food Safety Net 6 deaths in Netherlands from Q Fever (2009) (CDC, 2017; PHAC 2011)
Q Fever Overview
Image credits: CDC & MRCP
INDIANA UNIVERSITY BLOOMINGTON (CDC, 2017; PHAC 2011)
Q Fever Pathogen Data
• Class of proteobacteria, spore-forming coccobacillus • Coxiella burnetti is the causative agent of Q fever • 60% of cases are asymptomatic • Manifestations vary by strain, route of transmission, inoculum size, country, age, gender
• Host range: Humans and wild and domestic animals (cattle, sheep, goats, cats, dogs) • Vector: Aerosols of infected animals, arthropods (i.e. ticks) can transmit between species • Infectious dose: 1-10 organisms! • Incubation period: 13-28 days through respiratory route; 24-48 hours with accidental inoculation
INDIANA UNIVERSITY BLOOMINGTON (CDC, 2017; PHAC 2011)
Q Fever Transmission, Symptoms, Treatment
• Transmission: Contaminated aerosols from amniotic fluid, placenta, contaminated wool (airborne organisms can be carried miles downwind), direct contact with infected animals, dried excreta, contaminated hides, straw, fertilizer, laundry of exposed persons, ticks, ingestion of raw milk products
• Symptoms • Acute Q Fever (less fatal): Flu-like, atypical pneumonia, hepatitis, severe headaches, myalgia, severe sweats, rash (rare) • Chronic Q Fever: in immunocomprised (>6 months), fever, hepatitis, weight loss, stroke, heart failure; associated with high mortality rate
• Treatment: Resistant to several antibiotics; requires in vitro assays in HEL cells
• More difficult to kill (i.e. cannot use bleach)
INDIANA UNIVERSITY BLOOMINGTON (CDC, 2017; PHAC 2011)
Bioterrorism Concerns
• Described as potential bioterrorist agent
• Select agent as part of regulations from 42 CFR Part 73
• Extremely resistant to heat, drying and many common disinfectants
• Easily infect people by breathing in contaminated dust
• Previously weaponized for biological warfare
INDIANA UNIVERSITY BLOOMINGTON Lessons Learned from the 2014- 2016 West Africa Ebola Epidemic Ebola Virus
• Extremely infectious acute, viral hemorrhagic fever
• Caused by single-stranded negative sense RNA Ebola virus (Filoviridae family)
• Disease with high case fatality rate (~50%)
• Infectious dose: 1-10 organisms
• 20 previous outbreaks of Ebola and Marburg virus
• 2014 West Africa Ebola outbreak caused by Zaire ebolavirus (five species)
(CDC, 2016; Heymann, 2015)
Ebola is a Category A Agent
Sample Category A Definition Agents • Easily disseminated • Anthrax (Bacilis anthracis) • High mortality • Botulism (Clostridium • Can cause public panic and social disruption botulinum toxin) • Require special public • Plague (Yersinia pestis) health action • Smallpox (Variola major) • Cannot be transported without special • Tularemia (Francisella permissions unless tularensis) virus is inactivated • Viral hemorrhagic fevers
(CDC, 2016; PHAC, 2014) Ebola Cases in the United States
Total cases: 11
Cases contracted in the US: 2
Cases first diagnosed in the US: 4
Cases evacuated to US from other countries: 7
Total recoveries from Ebola: 9
Total deaths: 2
Information on U.S. Ebola cases available at http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/united-states-imported- case.html (CDC, 2016) Reproduction Number
Image credit: NPR, 2014 Are the Ebola outbreaks over? SECTION TITLE GOES HERE IF NECESSARY
References
1. CDC: Ebola
2. Heymann, D. L. (2016). Control of communicable diseases manual. American Public Health Association.
3. Public Health Agency Canada: PSDS
4. One Health: Engaging a Multidisciplinary Approach
5. UC Davis: One Health in Action, Emerging Pandemic Threats
6. https://www.cdc.gov/onehealth/basics/index.html
7. CDC Avian Influenza
8. CDC Swine Flu
INDIANA UNIVERSITY BLOOMINGTON