02 Challenges of infectious diseases

unideb 2025

What are the characteristics of infectious Diseases that set them apart from other human diseases?

1. Potential for unpredictable and explosive global impact

2. Frequent acquisition by host durable immunity against reinfection after recovery

3. Reliance of disease on a single agent without requirement for multiple cofactors

4. Transmissibility

5. Potential for becoming preventable

6. Potential for eradication

7. Evolutionary advantage over human host because of replicative and mutational capacities of pathogens that render them highly adaptable

8. Close dependence on the nature and complexity of human behavior

9. Frequent derivation from or coevolution in other animal species.

What are examples of established infectious disease?

1. viral and bacterial respiratory and diarrheal diseases

2. drug- susceptible malaria

3. tuberculosis

What are examples of newly emerging infectious diseases?

1. Nipah virus

2. SARS

3. Ebola

What are examples of re-emerging infectious diseases

1. West Nile virus in USA

2. resistant influenza

3. MRSA

4. drug-resistant malaria

5. polio in Africa

6. cholera in Haiti

7. anthrax release in 2001

incubation period of ebola virus disease

2-21 days

When are humans infectious in ebola virus disease?

Until they develop symptoms

first symptoms in evola virus disease

sudden onset of fever, fatigue, muscle pain, headache and sore throat

What symptoms follow after the first symptoms in ebola virus disease?

1. vomiting

2. diarrhea

3. rash

4. symptoms of impaired kidney and liver function

5. internal and external bleeding (oozing from gums, blood in stools)

laboratory findings in ebola virus disease

1. low white blood cell count

2. low platelet count

3. elevated liver enzyme

How do we diagnose ebola virus disease?

1. ELISA

2. Ag-capture detection test

3. serum neutralization test

4. RT-PCR assay

5. electron microscopy

6. virus isolation by cell culture

What are the factors that contributes to

reemerging diseases?

1. Human demographics and behavior

2. Technology and industry

3. Economic development and land use

4. International travel and commerce

5. Microbial adaptation and change

6. Breakdown of public health measures

What are the biggest challenges for infectious diseases in the 21st century?

1. Nosocomial infections

2. Antimicrobial-resistant pathogens

3. Emerging zoonotic and vector-borne diseases

4. Bioterrorism

What is nosocomial infection

1. Infection that is acquired in a hospital or health care facility.

2. The patient must have been admitted for other reasons from newly acquired infection

3. He or she must also not show signs of active or incubating this new infection

What are MDR organisms

microorganisms, predominantly bacteria, that are resistant to one or more classes of antimicrobial agents

What happens to those who have a drug-resistant organism infection?

1. more likely to have longer hospital stays

2. require treatment with second- or third-choice drugs that may be less effective, more toxic, and/or more expensive

What are the common drug-resistant bacteria?

Bad Bugs: No ESKAPE (ESCAPE)

1. Enterococcus

2. S. aureus

3. Klebsiella spp./Clostridium difficile

4. Acinetobacter

5. P. aeruginosa

6. Enterobacter spp.

What does beta lactamase hydrolyze?

extended spectrum cephalosporins, penicillins, and aztreonam

What bacteria do beta lactamase mostly associated with?

E. coli and Klebsiella pneumoniae

Beta lactamase is usually mediated by?

plasmid

What antibiotic resistance is encoded on the same plasmid?

Aminoglycoside, ciprofloxacin and trimethoprim-sulfamethoxazole

How do we prevent antimicrobial resistance?

1. prevent infection

2. diagnose and treat infection effectively

3. use antimicrobials wisely

4. prevent transmission

How do we prevent infection?

1. Vaccinate

2. Get the catheters out

How do we diagnose and treat infection effectively?

1. Target the pathogen

2. Access the experts

How do we use antimicrobials wisely?

1. Practice antimicrobial control

2. Use local data

3. Treat infection, not contamination

4. Treat infection, not colonization

5. Know when to say “no” to vanco

6. Stop treatment when infection is cured or unlikely

How do we prevent transmission?

1. Isolate the pathogen

2. Break the chain of contagion

What is Antimicrobial Stewardship?

1. involves the optimal selection, dose and duration of an antibiotic

2. resulting in the cure or prevention of infection with minimal unintended consequences to the patient

3. including emergence of resistant, adverse drug events, and cost

examples of emerging zoonosis

1. Avian influenza virus

2. Bats: Nipah virus

3. Ebola virus

4. Marburg virus

5. Borrelia burgdorferi

6. Ixodes scapularis

7. Lassa fever

8. Hantavirus Pulmonary Syndrome

What is bioterrorism?

Possible deliberate release of infectious agents by dissident individuals or terrorist groups

What are characteristics of biological agents?

1. attractive instruments of terror-easy to produce

2. mass casualties

3. difficult to detect

4. widespread panic & civil disruption

What are biological agents with the highest potential?

1. B. anthracis

2. C. botulinum toxin

3. F. tularensis

4. Y. pestis

5. Variola virus

6. Viral haemorrhagic fever viruses

What does Bacillus anthracis cause?

1. cutaneous anthrax: black eschar on skin

2. gastrointestinal anthrax: ingestion of spores in contaminated food

3. inhalation anthrax: generally none unless bioterror or lab accident

What are the biggest challenges for treating infectious diseases in 21st century?

1. Development of new antibiotics

2. Treating infections without antibiotics

3. Development of new vaccines

4. New diagnostic methods

5. Prevention of new epidemics, pandemy