[MICRO20] LEC 14: Emerging and Re-emerging Infections (Flashcards)

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