EMERGING PATHOGENS
Diagnosis of Ebola
Specimen culture (confirmatory)
ROUTES OF TRANSMISSION
1. Direct contact 2. Indirect contact 3. Vectors
CLASSIFICATION OF EMERGING INFECTIOUS DISEASES (EID)
1. Newly Emerging Infectious Diseases 2. Re-Emerging Infectious Diseases 3. Deliberately Emerging Infectious Diseases 4. Accidentally Emerging Infectious Diseases
SOURCES OF EMERGING/RE-EMERGING PATHOGENS
1. People 2. Animals and birds 3. Environment 4. Food and water
FACTORS ATTRIBUTED TO THE EMERGENCE/RE-EMERGENCE OF PATHOGENS
1.Globalization 2.Travel 3.Social events -Population growth -Migration -Economic impoverishment -Urban decay -War/civil conflict 4.Environmental changes 5.Developments in healthcare 6.Human activities
THE FIRST STEP IN THE SUCCESS OR FAILURE OF EMERGING PATHOGENS
1.Novel pathogens are often derived from other species 2.Pathogens are not equal across species 3.Pathogen success and failure 4.Prediction through surveillance
Transmission of Zika Virus
Aedes genus (Aedes aegypti) bite -During daytime -Peak: early morning, late afternoon/ evening Sexual transmission Mother to fetus Laboratory exposures Blood transfusion (being investigated)
SARS-CoV2 (COVID-19)
Affects different people in different ways Most infected people will develop mild to moderate illness and recover without hospitalization Through bats NOT pangolin Wuhan, China late 2019
Management of SARS-CoV2 (COVID-19)
Airborne, droplet, and contact precautions Frequent hand hygiene Respiratory etiquette Environmental cleaning and disinfection Maintaining physical distances and avoidance of close, unprotected contact with people with fever or respiratory symptoms Negative pressure room Vaccines -Pfizer COVID-19 vaccine (BNT162b2) -Moderna -AstraZeneca/ Oxford COVID-19 vaccine -COVID-19 vaccine Ad26.COV2.S -Sinovac
EMERGING INFECTIOUS DISEASES (EID)
An infectious disease whose incidence has increased recently (in the past 20 years), and could increase in the near future Minority that are capable of developing efficient transmission between humans can be major public and global concerns as potential causes of epidemic or pandemics Can be caused by newly identifies microbes, including novel species or strains of virus
Signs and symptoms of Ebola
Appear 2 days to 3 weeks post exposure -Depending on the virulence of the pathogen and comorbidities and state of the immune system of the host -It can take from 2 to 21 days, but usually 8 to 10 days after infection for signs of Ebola to appear. Symptoms can seem like the flu at first-sudden fever, feeling tired, muscle pains, headache, and sore throat -As the disease gets worse, it causes vomiting, diarrhea, rash, and bruising or bleeding without an injury, like from the eyes or gums -Usually has no symptoms for two to 21 days → the incubation period Fever, sore throat, muscle, headache (initial) → flu like sings and symptoms GI s/sx: vomiting, diarrhea, rash → MODS (liver and kidney failure) → bleeding → DEATH (6-16 days post appearance of signs and symptoms) MORTALITY RISK: 25%-90% (average = 50%)
Vectors
Arthropods such as ticks, mosquitoes and sand flies have been identified as vectors in many cases of emerging pathogens
Prevention of MERS-CoV
Avoiding unpasteurized or uncooked animal products Practicing safe hygiene habits in health care settings and around dromedaries Community education and awareness training for health workers Implementing effective control measures
Transmission of Ebola
Blood, body fluids Direct contact with blood, secretions, organs or other body fluids of infected living or dead persons or animals Human-to-human transmission is a predominant feature of this epidemic
"BUSH MEAT"
Catchall phrase for the meat of wild animals Refers to the remains of animals killed in the forests and savannas of Africa
MERS-CoV
Coronaviruses are a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS) Virus transferred to humans from infected dromedrary camels It is a zoonotic virus Identified in dromedaries in several countries in the Middle East, Africa and South Asia
Deliberately Emerging Infectious Diseases
Diseases created by humans for bioterrorism Example: Anthrax
Accidentally Emerging Infectious Diseases
Diseases created or spread unintentionally by humans Example: vaccine-derived poliovirus
Re-Emerging Infectious Diseases
Diseases that have spread to new places or which previous treatment no longer control Such as methicillin-resistant Staphyloccocus aureus
Newly Emerging Infectious Diseases
Diseases that were not previously described in humans, such as HIV/AIDS Example: COVID-19
Precautions of MERS-CoV
Droplet/ airborne, contact, eye Contagious (close contact)
After Ebola
Ebola survivors have certain proteins called antibodies, in their blood that may protect them from the same strain of the virus for 10 years or more. But no one knows if they can get sick from the other strains Its rare, but the Ebola virus can stay in semen for 3 months after a man recovers, so they should avoid sex or use a condom to keep frim infecting others. The virus can stay in breast milk for 2 weeks after recovery, so women shouldnt breastfeed during that time
EBOLA
Ebola virus disease (EVD) 1976 (Sudan) 2014 (Guniea, Sierra Leone, Liberia, Nigeria) Other name: Ebola hemorrhagic fever (EHF) 5 strains (As of 2022) Rare and deadly disease in people and nonhuman primates Viruses that cause EVD are located mainly in sub-Saharan Africa People can get EVD through direct contact with an infected animal (bat or nonhuman primate) or a sick or dead person infected with Ebola virus It kills up to 90% of people who are infected
Food and water
Example: Mycobacterium paratuberculosis and milk Cryptosporidium spp. And water
People
Example: Mycobacterium tuberculosis migrant/ refugee populations Epidemic strains of Neisseria meningitidis
Animals and birds
Example: West Nile virus and migratory birds H5N1 and migratory birds Equine morbillivirus and equine workers
Environment
Example: global warming and the increase in malaria Deforestation and Borrelia burgdorferi
Risks of Ebola
Family members or friends take care of someone who is ill or when funeral preparation and burial ceremonies do not follow strict infection prevention and control measures Occur in clinical and other health care settings, when health care workers patients and other persons have unprotected contact with a person who is infected Direct contact with the body fluids of the infected person Sharing food/ drink or kissing with infected Ebola person -Through saliva Not spread by breathing air -And the airborne particles it contains from an infected person Air, food, water do not carry the virus Blood, stool, vomit: MOST INFECTIOUS Semen, urine, sweat, tears, breast milk - may carry virus Infected fluids, linens/needles with infected fluids → enter mouth, nose, eyes, genitals, skin break of new host
Signs and symptoms of MERS-CoV
Fever, cough, and/or shortness of breath, myalgia Pneumonia GI s/sx - diarrhea SIRS (systemic inflammatory response syndrome) → respiratory failure → MODS (multiorgan dysfunction syndrome) → death Occurrence: immunocomprmised, with co-morbidities One can be MERS-CoV (+) and asymptomatic
Transmission of MERS-CoV
From animals (infected dromedary camels) to humans -Arabian one hump camels -Major reservoir host for MERS-CoV and an animal source of MERS infection in humans Humans to humans (close contact) -No sustained human-to-human transmission has been documented (As of April 2022)
Signs and symptoms of Zika Virus
Incubation period → few days to a week Duration of signs and symptoms → 2-7 days Conjuntivitis Malaise Joint pains Fever (>38℃ - low grade fever) Headache Rash Manifestations of the diseases are NON LETHAL Rarely kills Majority of the signs and symptoms are MILD
Transmission of SARS-CoV2 (COVID-19)
Incubation: 7-14 days -1 to 12.5 days (WHO, 2021) Close contact and one person inhales small droplets -Produced by an infected person (symptomatic or not) coughing, sneezing, talking, or singing Through fomites in the immediate environment around the infected person Airborne transmission may be possible
Prevention of Ebola
Infection control -Barrier isolation, PPE -Sterilization of equipments and surfaces -Proper care with bushmeat/ wildmeat food Quarantine Contact tracing (monitor for 21 days)
Direct contact
Many emerging pathogens have their primary route of transmission by direct contact with an infected individual or Secretions from such an individual
EMERGING PATHOGENS/RE-EMERGING PATHOGENS
Micro-organism, including viruses, bacteria, fungi and parasites, behave in a similar fashion to humans, in that they strive to perpetuate their own species, thus ensuring their continued survival Micro-organisms will exploit social, cultural, geophysical, and climate opportunities to persist as well as affect new susceptible host populations
Complications of Zika Virus
Microcephaly GBS
Progression of SARS-CoV2 (COVID-19)
Mild to moderate (mild symptoms up to mild pneumonia): 81% -Does not necessitate hospitalization Severe (dyspnea, hypoxia, or >50% ling involvement on imaging): 14% -Usually admitted in acute MS unit Critical (respiratory failure, shock, or multiorgan system dysfunction): 5% -Admitted in ICU/CCU
ZIKA VIRUS
Mosquito-borne flavivirus Uganda Monkeys (1947) Named after Zika Forest, Uganda
Signs and symptoms of SARS-CoV2 (COVID-19)
Most common -Fever -Dry cough -Tiredness Less common symptoms -Aches and pains -Sore throat -Diarrhea -Conjunctivitis -Headache -Loss of taste or smell -A rash on skin or discoloration of fingers or toes
Management of MERS-CoV
No known cure Quarantine/ isolation Supportive and s/sx management -Medications: Interferon, ribavarine, lopinavir, loperamide Contact tracing Precautions -PPE Vaccines still under preclinical/ clinical trials as of April 2022
Treatment of Ebola
No known cure Standard support Intensive care Inmazeb is a mixture of three monoclonal antibodies (mAbs) -Atoltivimad, maftivimab, and odesivimab-ebgn Currently there are no licensed vaccines to prevent Ebola virus disease rVSV-ZEBOV (Ervebo) vaccine developed by Merck
Treatment of Zika Virus
No vaccine yet July 2016 -"ZPIV" vaccine clinical trials started early 2017 Supportive treatment
RE-EMERGING PATHOGENS
One whose incidence is increasing in an existing host population as a result of long-term changes in its underlying epidemiology Examples: Ebola SARS
Complications of SARS-CoV2 (COVID-19)
Pneumonia Hypoxemic respiratory failure/ ARDS Sepsis and septic shock Cardiomyopathy and arrhythmia Acute kidney injury Complications from prolonged hospitalization -Secondary bacterial infections, thromboembolism, gastrointestinal bleeding, and critical illness polyneuropathy/myopathy
PPE (CDC ENHANCED GUIDELINES)
Remove PPE slowly and deliberately Inspect PPE, hand hygiene, remove shoe covers, remove outer gloves, inspect inner gloves, remove face shield, hand hygiene, remove hood, hand hygiene, remove gown, hand hygiene, remove inner gloves, hand hygiene, apply new pair of gloves, remove N95 respirator, hand hygiene, apply disinfectant wipes to clean shoes, hand hygiene, remove gloves, hand hygiene, inspection
Viral testing for SARS-CoV2 (COVID-19)
SARS-CoV-2 RNA by reverse transcription polymerase chain reaction (RT-qPCR) -Gold standard-99% accuracy -Nasopharynx samples compared to oropharynx/ throat samples -Detected in stool and blood Antigen test -A rapid diagnostic test suitable for point-of-care (POC) testing -Presence or absence of an antigen -Commonly used for the detection of SARS-CoV-2 (COVID-19) -Nasopharyngeal or anterior nasal swab specimens during ACUTE phase -Lesser accuracy -Timing is key → testing must be done on the 4th or 5th day Saliva-based test RT-PCR -Morning saliva preferred (higher viral load) -Patients should not eat, drink, brush their teeth, use mouthwash or smoke for at least 30 minutes before sample collection
Prevention of Zika Virus
Safe sexual practices/ sexual abstinence -6 months (symptomatic) -8 weeks after travel to known Zika infested countries (asymptomatic) Protection against mosquito bites -Light colored clothes, long sleeves and pants -Breeding sites for mosquitoes -Insect repellants
Diagnosis of Zika Virus
Signs and symptoms Travel history Reverse transcription-polymerase chain reaction (rRT-PCR) -Saliva, semen, blood -Urine (Less than 14 days post s/sx onset) Test done to pregnant who traveled from Zika areas -2-12 weeks after travel
Management (Severe type) of SARS-CoV2 (COVID-19)
Supportive management of the most common complication of severe COVID-19 Antiviral drugs -Remedisivir, favipiravir and merimepodib -Remdesivir IV -Molnupiravir PO Dexamethasone -Prednisone, methylprednisone or hydrocortisone Immune-based therapy -Convalescent plasma Extracorporeal membrane oxygenation (ECMO) -Extracorporeal life support -Extracorporeal technique of providing prolonged cardiac and respiratory support Hemoperfusion -An extracorporeal blood purification modality that consists of the passage of anticoagulated whole blood through a device, usually a column, that contains adsorbent particles -It is used for the removal of toxins in poisonings and has been used for the removal of cytokines in septic patients in some centers
EMERGING PATHOGENS
The causative agent of an infectious disease whose incidence is increasing following its appearance in a new host population or whose incidence is increasing in an existing host population as a result of long-term changes in its underlying epidemiology An infectious agent whose incidence is increasing following its first introduction into a new host population Switches from one host to another (species 'jumps') Led to some of the most devastating disease epidemics recorded
Indirect contact
The ingestion of contaminated food or water with emerging pathogens
Diagnosis of MERS-CoV
Travel history S/sx manifestations Chest x-ray -Both patchy infiltrates consistent with viral pneumonitis lower based Chest CT -Interstitial infiltrates CBC -Low WBC and lymphocytes Polymerase chain reaction (PCR) test -Copies of a particular DNA sequence Specimen: sputum, nasopharyngeal swab, tracheal aspirate N gene sequence assay -For confirmation