ERHS 430 - Exam 2
What is the global burden of HIV/AIDS?
38 million people living with AIDS in 2019, More than 70 million since 1983, >35 million deaths 690,000 deaths due to AIDS-related illness in 2019, decreased by 80,000 from previous year HIV/TB = leading cause of AIDS-related death (1 in 3) (33-50% of world population has TB) Peak transmission year: 1996 (Has since stabilized) Annual cost globally: $20 billion
Describe the definitive diagnosis of prion diseases.
A brain biopsy (immunohistochemical detection of protein) performed after death is the only way to confirm a prion disease. MRI, EEG, and CSF tests, tonsillar/lymphoid biopsy, and prion amplification assays can also be performed while the patient is alive.
What is an aberrant host and why is disease different in these cases?
A host becomes aberrant when a parasite cannot escape and dies inside the host. A disease is different in these cases because the parasite can infect various organs or leave blistery tracts throughout the skin.
What is the difference between a reservoir host and an incidental host?
A reservoir host is infected by a disease, but experiences no corresponding symptoms. Amplifying hosts rapidly replicate the infectious agent in high concentrations.
What is an arbovirus?
An anthropod-borne virus
What is an opportunistic pathogen? Give examples.
An opportunistic pathogen is an organism that becomes pathogenic following a perturbation to their host (e.g., disease, wound, medication, prior infection, immunodeficiency, and ageing). Examples include invasive pulmonary aspergillosis, allergic pulmonary aspergillosis, chronic pulmonary and aspergilloma, and severe asthma with fungal sensitization.
What is antibody dependent enhancement and how does it alter Dengue pathogenesis?
Antibody dependent enhancement is caused by subsequent infections with different genotypes of Dengue. This alters the disease into a much more severe form. Since there is a lack of herd immunity, anyone can be infected with any of 4 genotypes.
What is the difference between CJD and vCJD?
CJD symptoms→ early neurologic signs and signs of dementia vCJD symptoms→ psychiatric and behavioral symptoms, sensory distortions, delayed neurologic signs. The average duration of illness of CJD is 4-5 months, while vCJD is 13-14 months. vCJD mostly occurs in younger patients, the average age of death (28) is much lower than CJD (68). CJD is caused by a genetic mutation, while vCJD is caused by consuming contaminated beef products or by blood transfusion (rarely).
How does Coccidioidomycosis differ from other communicable diseases discussed in class?
Coccidioidomycosis is a soil-borne pathogen and most of the cases are in the southwestern US, whereas other communicable diseases are spread through contact, vectors, airborne droplets, or a common vehicle.
How does Coccidioidomycosis interact with one-health concepts?
Coccidioidomycosis research attempts to conserve healthy environments, animals, and people. Similar climates may become more at risk as climate change alters weather patterns (rainfall). This, in turn, determines the amount of animals and humans that may become infected. By protecting one of the aspects of One Health, we are protecting all of the aspects of One Health, they are all interconnected.
What species does Mad Cow Disease (BSE) infect?
Cows
Which viruses discussed have a zoonotic reservoir host and which are vector borne?
Ebola → zoonotic Dengue → vector-borne
List the modes of transmission for Ebola and Dengue
Ebola: Blood or bodily fluids, contaminated needles (etc), contact with infected bats or primates, sexual transmission Dengue: Human-mosquito-human cycle (Aedes spp).
Describe risk factors for contracting the diseases discussed.
Ebola: Living or travelling to Africa, women who are caretakers of the family, contact with fruit bats or primates, medical personnel, those who prepare infected bodies for burial. Dengue: Living or traveling to tropical regions, having dengue before increases likelihood
Describe ecological drivers for each virus discussed.
Ebola: human practices put people in closer contact with wildlife, such as bushmeat hunting, entering bat caves, and habitat loss for primates. Funeral practices and lack of resources, sanitation, PPE also contribute. Dengue: short-term changes in weather (temperature, precipitation, humidity) can increase incidence. Climate may influence mosquito distribution and density. Population growth, urbanization, poor sanitation, travel all contribute to increased incidence
What is the general geographic distribution and burden of disease for each virus?
Ebola: mostly West Africa, or associated with travellers from West Africa Dengue: mostly found in the tropics/equatorial region
State the hallmark symptoms for Lyme disease.
Erythema migrans (Bullseye rash).
Name at least one example from each class of eukaryotic pathogens.
Fungi: Coccidioidomycosis Algae: protothecosis Protozoa: Plasmodium (malaria) Helminths: tapeworms
What are the general clinical symptoms, treatment, and prevention for each disease?
General clinical symptoms for mild cases include fever, headache, muscle or joint pain, and skin rash, while severe cases include symptoms of high fever, confusion, tremors, seizures, paralysis, coma, or death. Supportive care is the common form of treatment. Prevention methods are to avoid mosquitoes and endemic regions.
What are the standard methods of treatment and prevention for the diseases discussed?
HPV: vaccine Chlamydia and Gonorrhea: antibiotics Syphilis: penicillin HIV/AIDS: Antiretroviral Therapy (ART)
List the general characteristics of hemorrhagic disease
Hemorrhagic diseases cause an inappropriate immune response that leads to liver damage, vascular leakage, pulmonary edema, and disseminated intravascular coagulation (DIC). They often end in shock and death. Examples: Ebola and Dengue.
Discuss climate related issues and human activities that play a role in the present and future state of Coccidioides spp.
Hotter, drier, less vegetative climate. Wind, construction, and agriculture cause dust emissions and soil disturbance. Occupational and socioeconomic are human exposure factors. Human interaction and activity that influences the environment and immediate conditions can prove conducive to Coccidioides growth and exposure.
State the prevalence and overall global burden of disease of malaria.
Indigenous in 91 countries, ~80% cases are in 15 countries In 2016, ~216 million cases occurred worldwide with ~445,000 deaths.
What is the difference between an intoxication and an infection?
Intoxications require symptomatic care, infections require antibiotics or they can go away on their own. (Antibiotics don't eliminate toxins).
Which of the 5 viruses have a commercial human vaccine?
JEV - Japanese Encephalitis Virus
Which viruses described have a recent pattern of global emergence?
JEV and ChikV have a recent pattern of global emergence.
Which viruses discussed have zoonotic reservoirs?
Japanese Encephalitis Virus (JEV), Eastern Equine Encephalitis Virus (EEEV), and Rift Valley Fever Virus (RVFV)
State the global burden of disease for Leishmania and Schistosoma.
Leishmania: ~1 million caes/year Visceral: Over 300,000 cases each year, >200,000 deaths. 90% of visceral cases in India, Bangladesh, Nepal, Sudan, Brazil Schistosoma: >200 million people infected, 280,000 deaths annually
What is the general geographic distribution of Malaria and Lyme disease?
Malaria is most common in hot, humid climates with a lot of rainfall. This is the best breeding ground for mosquitoes. Lyme disease is most common in the northeast region of the US due to its vast forests and hot, humid summers. There are also large populations of mice and deer, which help the ticks spread across large areas.
How are both diseases treated and prevented? (generally, not specific drugs)
Malaria is treated with IV drugs. Prevention includes chemoprophylaxis (expensive) and mosquito control (nets, repellants). Lyme disease is treated with antibiotics and prevented by avoiding ticks.
State the vectors for Malaria and Lyme Disease
Malaria: Anopheles mosquitoes Lyme: black-legged ticks, Ixodes scapularis and Ixodes pacificus
State the organism name and type of pathogen for Malaria and Lyme disease
Malaria: Protozoan parasite, genus Plasmodium Lyme: Spirochete bacteria called Borrelia burgdorferi
What are the common STDs in the US?
Most common in the US: Human Papilloma Virus (HPV) Most reported in the US: Chlamydia
What is the ethical dilemma of the Tuskegee experiment?
No informed consent; study subjects (only black men) told they were being treated for "bad blood". They were never actually treated, even when penicillin became available. They were never given the option to quit the study, which lasted 40 years.
Which diseases are transmissible from person-to-person?
Norovirus, Typhoid Fever, Staphylococcus aureus, Cholera
What are the stages of syphilis?
Primary: skin lesions (3-90 days) Secondary: body rash (4-10 weeks) Latent: asymptomatic infection after primary and secondary phases Tertiary: affects internal organs, not contagious or treatable (3-15 years after initial infection)
What is the difference between a prion and other infectious agents?
Prions are not a bacteria or virus, so they don't have DNA or RNA, they are a neurodegenerative protein.
Which pathogens are readily treatable and which are prone to treatment failure?
Readily Treatable: Giardia, Leishmaniasis, tapeworms, hookworms, Larva migrans, flukes Prone to Treatment Failure: fungal infections, algal pathogens
What are some of the environmental risk factors for acquiring foodborne infections?
Risk factors: unsanitary conditions, lack of access to clean water, poor hygiene, lack of education about food safety Foodborne illnesses affect everyone: higher impact in developing nations Agricultural practices: industrialized vs. agrarian (more likely to be exposed)
What is the exposure environment that contributes to STIs?
STIs are most impacted by social, socioeconomic, and behavioral factors, such as poverty, socioeconomic status, gender (especially in areas with no equal rights), lack of education, and lack of access to healthcare.
Which foodborne diseases are zoonotic?
Salmonella, Clostridium perfringens, Clostridium botulinum, Campylobacter, Listeria monocytogenes, Escherichia coli, Hepatitis E Virus
Which prion diseases are zoonotic?
Scrapie, CJD, vCJD/Mad Cow Disease (BSE)
What are some of the risk factors associated with the pathogens discussed?
Some environmental risk factors include contaminated water or soil and temperate/tropical climates. This is due to heavy rainfall, flooding-poor sewage systems (downstream more at risk) and a lack of freezing seasons/refrigeration.
Describe the methods of transmission of prions.
Some prions are sporadic or hereditary, others are latrogenic (caused by medical examination or treatment), foodborne, bloodborne, or airborne (aerosol).
What is stigma and how does it relate to STIs?
Stigma is the disapproval or discrimination of a person/group based on their perceived characteristics. In regard to STIs, there is stigma attached to those infected, as they can be perceived as promiscuous, having a certain sexuality, or simply looked down upon.
List a couple of arthropod vectors
Ticks, Mosquitoes
What are the most prevalent foodborne diseases in the US?
Top 5 in the U.S.: Norovirus, Salmonella, Clostridium perfringens, Campylobacter, Staphylococcus aureus
What is the overall burden of disease caused by foodborne illness in the US? Globally?
US: 48 million people cases, 128,000 hospitalizations, and 3,000 deaths Globally: 420-960 million illnesses and ~420,000 deaths Norovirus is the most common foodborne illness in the world
Compare life cycle, differences in transmission, and progression of illness with other communicable diseases.
Valley fever is mostly asymptomatic, but there are primary (flu-like), chronic (like TB), and progressive (immuno-comprpmised people, infect every part of the body or lethal) forms. It is soil-borne, brought up by disturbance (aerosolized), spore inhalation, and infects the lungs first.
Which viruses discussed have human reservoirs?
Zika Virus and Chikungunya Virus
What species does Chronic Wasting Disease infect?
deer, elk, moose, reindeer, sika deer
What species does Creutzfeldt-Jakob Disease (CJD) infect?
deer, elk, reindeer, and moose
What species does Kuru infect?
humans (cannibalism)
What species does Scrapie infect?
sheep
