Healthy and unhealthy communities - Microbiology Flashcards
List the key factors determining the travel-related risk
- Mode of destination
- Destination (local infection epidemiology)
- Season of travel
- Duration of travel
- Standards of accomodation, food hygiene and sanitation
- Behaviour of the traveller / purpose of travel
- Underlying health of traveller
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Describe the importance the destination a travellor goes to is
- Destinations where accomodaton, hygiene, sanitations, water quality and medical care of a high standard result in ‘few risks to the health of travellers’
- Visitng major cities and tourist centres pose few serious risks
Describe how the behaviour of a travellor can expose them to risks?
- Going outdoors in the evenings in a malaria-endemic area without taking precautions
- Swimming in schistosoma infested lakes
- Exposre to insects, rodents, bats, and other animals
- Ingestingcontaminated food/water
- Unprotected sexual intercourse
a) What is gastroenteritis associated with?
b) Describe the epidiemiology of gastroenteritis
c) What are the two types?
d) What are the causative agents?
a) Associated with poor hygiene and sanitation
b) Worlwide in endemic areas, 1.5 million children die yearly due to infectious gasteroenteritis
c) Viral and bacterial gastroenteritis
c) Rotavirus, Norovirus, Astrovirus
List the bacterial gastroenteritis agents
- Campylobacter jejuni
- (Enterotoxigenic) E.coli
- Salmonella
- Shigella
- Vibrio cholerae
Gastroenteritis
a) Presentation
b) Diagnosis
c) Treatment
a)
- Anorexia
- Nausea
- Vomiting
- Diarrhoea
- Abdominal discomfort
b)
- Clinical evaluation
- Stool testing
c)
- Oral or IV rehydration
- Antibiotics in select bacterial cases if bacteraemia
Which viral hepatitis are enterically (food and waterbore) transmitted?
- Hepatitis E
- Hepatitis A
Infection charcteristics of hepatitis E
a) Transmission
b) Outbreak
c) Incubation
d) Attack rate
e) Mortalitiy
f) Severity of disease
g) Vaccine available
a) Faeces
b) Seasonal, often associated with monsoon period
c) 3-7 weeks
d) 1 in 2
e) <1% but 15-25% in antenatal women
f) Increases with age
g) Develope
a) What are the genotypes of hepatitis E
b) Which is the most prevalent genotype?
a) Genotype: 1,2,3 and 4
b) Genotype 1
Describe the prevention and control measures for travellers to hepatitis E endemic regions
- Avoid drinking water (and beverage with ice) of unknown purity, uncooked shellfish, and uncooked fruit/vegetables not peeled or prepared by traveller
- Vaccine developed
Infection characteristics of hepatitis A
a) Transmission
b) Site of infection
c) Severity of disease
d) Epidemiology
a) Faecal-oral route
b) Acute, self-limiting infection of the liver
c) Infection may be asymptomatic in children and adults symptomatic. Rarely, fulminant hepatitis (Clinical syndrome of severe liver function impairment can ensue)
d) Every year there are 1.5 million symptomatic cases
Describe the prevention of hepatitis A
Good hgygiene
Pre-exposure
- Active immunisation vaccine (killed whole virus - active within 14 days of first dose) for travellers to intermediate and high-risk areas
Post exposure
- Vaccine (within 7 days)
- Immunoglobulin HNIG (within 14 days of onset of disease in primary case)
There are athropod-associate travel infections.What is an anthropod?
Mosquitoes or ticks
List some examples of mosquito associated viral infections
- Dengue type 1,2,3,4
- Japanese encephalitis
- Murray valey encephalitis
- St louis encephalitis
- West Nile virus
- Zika virus
- Yellow fever
- Chikungunya virus
Dengue fever
a) Transmittance
b) Symptoms
c) Presentation of dengue haemorrhage fever
d) What are the severe consequences of fengue haemorrhage fever?
e) What are the differential diagnosis of fengue fever and why?
a) Transmitted to people by bite of Aedes mosquito that is infected with dengue virus
b)
- High fever
- Severe headache
- Severe pain behind eyes
- Joint pain
- Muscle and bone pain
- Rash
- Mild bleeding (e.g., nose or gum bleeds, easy bruising)
c)
- Fever that lasts 2-7 days, with general signs and symptoms consistent with dengue fever
- When the fever declines, symptomsinclude persistent vomiting, sever abdominal pain, and dysponea (shortness of breath) may develop
d) Haemorrhage follows leading to failure of the circulatory system and shock. This leads to death if not corrected
e) Chikungunya and zika virus as they are prevalent in the same areas as denge virus (subtropical and tropical areas of the world)
List some examples of tick-borne infections
- Tick-borne encephalitis
- Kyasunar forest disease (Alkhumra)
- Lounping ill
- Omsk haemorrhage fever
- Powosan
- Crimean-congo haemarrhagic fever
Crimean-congo haemorrhagic fever
a) Cause
b) Case fatality
c) Incubation period
d) What type of outbreak does it cause?
e) Symptoms
f) Worrying signs and can they lead to?
a) Caused by an infection with Nairovirus (tick-borne virus) in the family Bunyavirdae
b) 10-40%
c) Short (1-3 days)d) Haemorrhagic fever
e)
- Fever
- Myalgia
- Neck stiffness
- Backache
- Headache
- Photophobia
- Nausea
- Vomiting
- Diarrhoea
- Abdominal pain
- Mood swings
- Confusion
f) Bleeding into the skin, mucosa, internal organs
a) What are viral haemorrhagic fevers (VHFs)?
b) What is the term ‘viral haemorrhagic fever’ used to describe?
c) Characteristically,what occurs in viral haemorrhagic fevers?
d) Provide examples of some viral haemorrhagic fevers in Africa
a) Viral haemorrhagic fervers (VHFs) refer to a group of epidemc prone disease that are caused by several distinct families of viruses
b) The term “viral haemorrhagic fever” is used to describe a severe multi-system syndrome (multple organ systems affected)
c) Characteristcally, the overall vascular system is damaged and the body’s ability to regulate itself is weakened. Symptoms can oftern be accompanied with life-threatening bleeding
d) Marburg and Ebola haemorrhagic fevers, Crimean-congo haemorrhagic fever (CCF), Rift Valley fever (RVF), Lassa fever, yellow fever
Tuberculosis
a) Causation? and what is the most common causative agent?
b) Transmission
c) Epidemiolgy
d) What do you call people who are asymptomatic and not infectious?
e) What vaccine provides partial prtoection against TB?
f) Treatment? What issues can arise?
a) Caused by various strains of mycobacteria. Most commonely mycobacterium tuberculosis
b) About 1/4 of the worl is infected with mycbacteria. 10 million people fell ill with TB in 2017
c) TB is transmited by people inhaling airborne droplets produced by infectious TB carriers
d) Latent TB infection (LTBI) carriers
e) BCG (Bacillus Calmette-Guerin) vaccine
f) Standard treatment of TB consists of six-month regimen of 4 first-line drugs (isoniazid, rifampicin, ethambutol and pyrazinamide)
Issue - variants of TB are resistant to antibiotics which makes TB more difficul and expensive to treat and have higher fatality rates. This is known as multidrug-resistant (MBR) and extensively drug-resistant (XDR) TB
Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
a) Case-fatality rate
b) Major reservoir host
c) Symptoms
a) 35.5% transission human-to-human
b) Dromedary camels
c)
- Fever, cough, short of breath
- Pneumonia is common but not always present
- GI symptoms include diarrhoea
Rabies
a) Transmittance
b) Wich animals are the main source of human rabies death?
c) Epidemiology
d) Managment and treatment
a) Direct contact with saliva (usually through a bite) or brain/nervous system tissue from an infected animal of a rabid animal, most commonly dogs
b) Dogs
c) Infections cause tens of thousands of deaths every year, mainly in Asia and Africa
d) Immediate thorugh wound washing with soap and water after contact with a suspected rabid animal and then followed by post-exposure prophylaxis [(rabies vaccine and rabies immune globulin (RIG)]
Monkeypox
a) Transmittance
b) What is monkey pox similar to? What is the difference between them?
c) Case-fatality
d) Treatment
a) Viral zoonotic disease that is transmitted from various wild animals e.g., rodents and primates but has limited secondary spread from human-to-human transmission
b) The monkeypox virus is similar to huma smallpox (eradicated in 1980) however monkeypox is milder (still fatal)
c) 1-10% with most deaths occuring in younger age groups
d) There is no specific treatment or vaccine available although prior smallpox vaccination was highly effective in preventing monkeypox as well
Malaria
a) Causative agents
b) Transmittance?
c) Where and when does it most occur?
d) Epidemiology
a) Plasmodium falciparum, P. vivax, P.ovale (subspecies curtisi and wallikeri), P.malariae, P.knowlesi
b) Transmitted by the bite of female anopheline mosquitoes
c) Occurs throughout tropics and sutropics at altitudes below 1500 metres. Malaria transmission occurs during or just after the rainy season
d) 240 k deaths per year. Between 2000-2015 global incidence reduce by 41% but still causes 200 million cases per year
