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Nutrition & Infectious Disease
AM_470816, January 2022.
HC0: NID Introduction
● Infection = the presence of a (micro-) organism that is able to divide/reproduce.
● Illness = the moment at which the (micro-) organism causes (tissue) damage.
● Pathogen = a (micro-)organism that is able to cause illness.
Classification of infectious pathogens:
Infection versus illness:
Example tuberculosis:
- Mycobacterium tuberculosis.
- 90% asymptomatic (no illness).
- Can be reactivated after years.
- Immune deficiency (e.g. AIDS) can reactivate tuberculosis to cause disease/illness.
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Infection:
People that have less severe disease (just a few symptoms), other physical diseases. There
are a lot of people who have asymptomatic infections, who can infect people without
knowing. Whether you are (a)symptomatic, nutrition matters!
Child under-nutrition & immune functioning:
Interplay of malnutrition with environmental enteric ‘darm’ dysfunction and systemic
inflammation → Exposure to intestinal pathogens and intestinal dysbiosis ‘dysfunctie’, as a
consequence of poor sanitation and possibly specific nutrient deficiencies (e.g., zinc, vitamin
A, and protein):
→ intestinal inflammation
→ disruption of intestinal barrier function.
→ Impaired barrier function allows the translocation of bacteria and bacterial
products from the intestine, which activate innate immune cells in the mesenteric lymph
nodes, liver, and systemic circulation to generate proinflammatory cytokines. The increased
systemic inflammation carries a metabolic cost and leads to impaired host defense.
Collectively, these vicious cycles lead to growth faltering ‘haperende groei’ and increased
mortality.
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Infection → undernutrition:
Plasmodium (malaria) and Hookworm (worm) → could both lead to anemia.
Hookworm: ancylostoma duodenale/ necator americanus.
- Male worm 8-10mm, female worm 10-13 mm.
- Large buccal cavity ‘grote mondholte’ with cutting teeth.
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- Life span 1 year, sometimes longer.
- Lifecycle:
- Within 1-2 days larvae develop (under warm, humid ‘vochtige’ conditions).
- Larvae grow in/on feces or on soil (bodem).
- After 5-10 days development of infectious larvae (can migrate and survive for
weeks).
- Migration via vascular system, lungs, trachea to intestine.
- 24 hours after infection in intestine larvae attach and develop into adult worms.
- If orally infected by A. duodenale no lung passage.
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Symptoms hookworm infection:
- Local skin manifestation (huidirritatie), (ground itch (jeuk) during penetration of the
larvae).
- Airways: during lung migration (coughing, sputum, fever).
- Intestine: abdominal pain, diarrhea, weight loss, and tiredness.
Nutrition and hookworm infection:
● Iron deficiency anemia: caused by attachment, blood loss, secretion of
anticoagulants.
● Protein energy malnutrition: caused by vomiting, reduced food intake, diarrhea.
HC1: Infectious Disease Epidemiology
History of Infectious Disease Epidemiology:
Dr. John Snow:
- Cholera outbreak in London 1854.
- Hand-draw map: what was the source of the disease?
- Water Pump handle was taken off.
- The source of the disease was not found until 1883. In 1883 it was found by Robert
Koch, he discovered vibrio cholerae.
Special features Infectious Disease Epidemiology:
Why is infectious disease epidemiology different from non-infectious disease epidemiology?
(1) A case (a person with an infectious disease) may also be a risk factor.
● Transmission of disease between cases.
● Contact patterns in society are important.
