LEC 14 - Emerging and Re-Emerging Infections
LEC 14 - Emerging and Re-Emerging Infections
Re-emerging Infectious Disease
Disease that was previously controlled but has risen again to be a significant health problem.
mortality, morbidity
TB is the 8th leading Cause of ___ and 10th Leading Cause of ___ in the Philippines.
Primary Complex
If the child’s immune system is not so strong, ___ can lead to massive hematogenous dissemination, leading to Miliary TB.
culture
The gold standard for laboratory confirmation of TB disease
testing
Part of the National Tuberculosis Program of DOH that is done to identify bacteriologically confirmed or clinically diagnosed TB cases; use of rapid TB molecular test as the primary diagnostic tool – GeneXpert/TB LAMP/TrueNAT
Emerging Infectious Diseases (Ereid)
Has emerged and incidence in humans increased in the last 2 decades and is continuously threatening to increase in the near future.
FACTORS CONTRIBUTING TO THE EMERGENCE OF INFECTIOUS DISEASES
Human demographics and behavior - transfer of people from one place to another Technology and industry Economic development and land use International travel and commerce Microbial adaptation and change Breakdown of public health measures Human susceptibility to infection Climate and weather Changing ecosystems Poverty and social inequality War and famine Lack of political will Intent to harm - bioterrorism
Wrong prescribing practices leads to ___
development of resistance to drugs
Deforestation
forces animals into close human contact - increased possibility for agents breach species barrier between animals and humans
Zoonoses
1,415 microbes are infectious for human Of these, 868 (61%) considered zoonotic 70% of newly recognized pathogens are zoonoses Emerging influenza infections in human associated with chickens, pigs
Hepatitis B
Identified several decades earlier Upward trend in all countries Prevalence >90% in high-risk population
Hepatitis C
First identified in 1989 In mid 1990s estimated global prevalence 3%
Mycobacterium tuberculosis
Obligate aerobe (needs oxygen to thrive) Slow-growing (takes up to 8 weeks to grow in culture) Nonmotile acid-fast bacilli
RISK OF TB TRANSMISSION
TB TRANSMISSION
Via airborne Active TB patients can infect 10-15 people annually if they do not practice proper precautions (e.g. cough etiquette)
Systemic TB
Fever Night sweats Easy fatigability Anorexia and weight loss
Pulmonary TB
Cough (>2 weeks) (most common symptom) Chest pain Hemoptysis Dyspnea
LIMITATIONS OF CULTURE:
Long turnaround time - 8 weeks/2 mos. to say if there is growth or none Access - not all labs have access to culture Cost - quite expensive
Drug susceptibility test
This is important because RIF resistance will give an initial clue that this might be a drug-resistant Mycobacterium tuberculosis
Specimens that can be submitted for GeneXpert:
Fresh sputum Sputum sediment bronchial washings (more invasive) Any Extra-pulmonary tuberculosis specimens (EPTB) e.g. lymph node aspirate, urine, CSF
Multidrug-Resistant TB (MDR TB)
Resistance to at least INH (Isoniazid) and rifampicin, the most potent anti-TB drugs
Different acid fast bacilli staining:
Ziehl-Neelsen - traditional; requires a heating step Kinyoun stain - “cold” acid-fast stain (missed out the heating step)
SIGNIFICANT RISK FACTORS OF TB
Age Urban dwelling Previous TB treatment Self-reported Diabetes Mellitus Lower socioeconomic status No health insurance Sex and smoking
FALSE
Correct statement: Reverse TRANSCRIPTION Polymerase Chain Reaction (RT-PCR) is the golden standard diagnostic test for SARS-CoV2.
TRUE or FALSE
Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) is the golden standard diagnostic test for SARS-CoV2.
FALSE
Correct statement: RT-PCR does not distinguish between infectious virus and viral genetic material remnants that is why it is NOT a good test for recovery.
TRUE or FALSE
RT-PCR does not distinguish between infectious virus and viral genetic material remnants that is why it is a good test for recovery.
2
Whenever RT-PCR is performed for SARS-COV2, a Biosafety Level ___ facility is required, and biosafety precautions must be observed.
Antibody Test
An indirect type of test because it tests the presence of Tests IgM, IgG or both.
FALSE
Correct statement: Best to test after at least 7 days of symptoms or exposure because during the first 7 days the disease, the body will not yet produced antibodies
TRUE or FALSE
Best to test after at least 5 days of symptoms or exposure because during the first 5 days the disease, the body will not yet produced antibodies
Plaque Reduction Neutralization Test (PRNT)
Gold standard for the antibody test
Rapid Test
More commonly utilized antibody test and provides point-of-care testing (gives immediate results). It is also cheap.
FALSE
Correct statement: Once an antibody test is validated, it can be used to assess recovery. For example, if it will show "IgG positive", then it will tell you that you had past COVID infection.
TRUE or FALSE
Once an antibody test is validated, it can be used to assess recovery. For example, if it will show "IgA positive", then it will tell you that you had past COVID infection.
RT-PCR
Which diagnostic test is used for suspected COVID-19 with symptoms and for highly exposed (HCWs) asymptomatic patients?
January 13, 2021
Date when Philippines was able to identify the first variant – SARS-COV2 UK Variant.
Spikes
SARS-CoV-2 has ______ that the virus uses to attach to human cells.
TRUE
TRUE or FALSE
Changes in the spike protein can result in changes in virus transmissibility or disease severity
FALSE
RNA viruses have a higher mutation rate than DNA viruses
TRUE or FALSE
DNA viruses have a higher mutation rate than RNA viruses
Strain
It is a variant with demonstrably different phenotype, such as difference in antigenicity, transmissibility, or virulence.
The WHO Virus Evolution Working Group (VEWG)
They monitor changes to SARS-CoV-2 to detect potential VOC and VOI that pose an increased risk to global public health
Greek
WHO recommends labels using letters of the ______ alphabet, such as Alpha, Beta, Gamma to label the variants of COVID-19.
Delta
Transmission of the _____ variant is higher than other variants of SARS-CoV-2
TRUE
TRUE or FALSE
Existing vaccines will still work against new variants of the virus since mutations alter only a minor piece of a large protein of the virus.
July 16, 2021
Date when the first local case of the Delta Variant was reported in the Philippines.
Ebola
Ebola was first discovered in 1976 near the ______ River.
Monkey
In what animal was Zika first discovered in the Zika Forest of Uganda in 1947?
Brazil
Which country is by far the most affected country of the Zika virus, reporting the most cases of people infected with the virus.
Candida auris
It is a novel ascomycetous yeast isolated from the external ear canal of an inpatient in a Japanese hospital. It causes invasive infections, predominantly fungemia, or fungi in the blood.
93% resistant to fluconazole (antifungal for Candida)
54% resistant to voriconazole (antifungal)
35% resistant to amphotericin B (antifungal)
7% resistant to echinocandins (antifungal)
4% resistant to azoles, amphotericin B, AND echinocandins
What are the drug resistance rates of Candida auris
TRUE
TRUE or FALSE
Candida auris have higher prevalence than other Candida species
FALSE
Correct statement: It forms white to cream colonies with a smooth edge on the Sabouraud-dextrose agar and pink colonies on CHROMagar Candida medium
TRUE or FALSE
It forms white to beige colonies with a smooth edge on the Sabouraud-dextrose agar and pink colonies on CHROMagar Candida medium
Studied by 35 People