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Flashcards in Travel Related Infction Deck (27)
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1
Q

How does increasing lglobal travel lead to infection

A
• Exotic destinations
• Underlying medical conditions 
• War / natural disasters
• Migration of populations 
• Emerging infections
• Non-infectious problems
– Accidents
2
Q

What person factors should be considered in travel related infections

A

At one point after they traveled did they get the symptoms
Think abt incubation periods - tropics and abroad
Good travel history
Where they went in the last few months

3
Q

What are some significant pathogens in

A

Bacteria - rickettsia/spirochaete (vectors)
Fungus - yeast, mound
Parasite - Protozoa, helminth (vectors)

4
Q

Why is the travel history important?

A

Recognise imported diseases (rare / unknown in UK)

Different strains of pathogen •Antigenically different
•Impacts on protection/ detection
•Antibiotic resistance

Infection prevention
•On the ward
•In the lab

5
Q

What factors should be taken as the history is taken?

A
Where have they been? - Sub-saharan Africa
S.E .Asia
S / C America
N. Africa / M. East
S / C Asia
N. Australia
N. America

When the symptoms began? - incubation period
< 10 days
10-21 days
>21 days

What are the symptoms? -
Resp (SOB/cough) GI (diarrhoea) Skin (rash) Jaundice CNS (headache / meningism) Haematological (lymphadenopathy / splenomegaly / haemorrhage) (Eosinophilia)

How did they acquire it? -
Food/water Insect/tick bite Swimming Sexual contact Animal contact (bite/safari) Recreational activities

6
Q

What are specific risk factors for travel related infection

A

Animal bite Rodents Mosquito / insect bite Tick bite Dead / slaughtered animals Anthrax; Rift Valley; CCHF; Ebola; Marburg; monkey pox Farms Game parks Fresh water Caves Unpasteurised dairy Shellfish Under / uncooked fish / meat

7
Q

What are other aspects o travel history

A
  • Any unwell travel companions /contacts?
  • Pre-travel vaccinations / preventative measures?
  • Healthcare exposure?
8
Q

What are the 5 main species of plasmodium and what transmits it

A
• 5 main species of
Plasmodium
– falciparum 
– vivax 
– ovale 
– malariae 
– knowlesii
Concentrate on first 2
• Vector - female Anopheles mosquito
9
Q

Describe the number of cases of malaria per year

A
• 250 million cases and
1million deaths each
year 
• Commonest imported infection to UK 
• ~1500 cases per year
– Up to 11 deaths/year 
– 75% falciparum (90% cases from Africa, mortality 10- 20%) 
– Remainder mostly vivax/ovale (90% cases from India)
10
Q

Describe the symprtoms of malaria

A
Central - headache
Systemic - fever
Muscular - fatigue, pain
Back - pain
Skin - chills, sweating
Respiratory - dry couch 
Spleen - enlarge 
Stomach - nausea, vomiting
11
Q

Describe the history and examination of malaria

A
• Incubation period:
– Minimum 6 days
– P. falciparum: by 4 weeks
– P. vivax/ovale: up to 1 year+ • History
– Fever chills &amp; sweats - cycle
every 3rd or 4th day
• Examination
– Often few signs except fever
(+/- splenomegaly)
12
Q

Describe the symptoms of severe falciparum malaria

A

See slid

13
Q

Describe the malaria life cycle

A

Mosquito feeds - malaria parasite into bldstream, infect over cells, parasite develops, creating 10s of 1000s ofwhich burst out of liver cell, affect heathy RBCs, infect and burst cell, liberating morparticles, destroy Moore rbcs, some stay in rbcs called gametophytes, if another mosquito feed, the gamerocytes infect another mosquito which can then go on to infect another human

14
Q

Describe the investigations and treatment of malaria

A

• Malaria should be managed by an ID physician
• Blood film x3
• FBC, U&Es, LFTs, glucose, coagulation
• Head CT scan if
neurological symptoms
• CXR

• Treatment depends on
species
– P. falciparum (‘malignant’)
• Artesunate
• Quinine + doxycycline 
– P. vivax, ovale, malariae
(‘benign’)
• Chloroquine
• Dormant hypnozoites (liver)
– Can recur months-years
later 
– Give additional primaquine
15
Q

Describe typhoid/paratyphoid

A

Typhoid & paratyphoid (enteric fever) • Mainly Asia (also Africa & S America) –
poor sanitation • 21 million cases/year, mainly children • UK: travel-related
– ~500 cases/yr (mainly Indian subcontinent) • Mechanism of infection
– faecal-oral from contaminated food/water
– source is cases or carriers (human pathogen
only)

16
Q

Describe the salmonella organisms

A
• Salmonella typhi 
• Salmonella paratyphi
A, B or C
– Enterobacteriaceae:
aerobic Gram-negative bacillus
Virulence 
– Low infectious dose
– Survives gastric acid
– Fimbriae adhere to epithelium over ileal lymphoid tissue (Peyer’s patches) → RE system / blood
– Reside within macrophages (liver/ spleen/ bone marrow)
17
Q

What are the symptoms and signs off enteric fever

A
Enteric fever - symptoms &amp; signs
• Systemic disease (bacteraemia/sepsis) 
• Incubation period: 7-14 days 
• Fever, headache, abdominal discomfort, dry cough 
• Relative bradycardia 
• Complications
– intestinal haemorrhage &amp; perforation; seeding
– 10% mortality (untreated)
– Chronic carrier state 1-5% 
• Paratyphoid: generally milder
18
Q

Describe the investigations for enteric fever

A

• Moderate anaemia • Lymphopaenia • Raised LFTs (transaminase & bilirubin) • Culture
– Blood (+ve in 40-80%)
– Faeces, bone marrow • Serology (antibody detection) not reliable

19
Q

Describe the reatment for enteric fever

A

• Multi-drug resistant (including penicillins) • Fluoroquinolones (eg ciprofloxacin) may
work, but increasing resistance • Usually treated with IV ceftriaxone
(cephalosporin) or azithromycin
(macrolide) for 7-14 days

20
Q

Describe the prevention for enteric fever

A

• Food & water hygiene precautions • Typhoid vaccine
– High-risk travel
– Laboratory personnel • Capsular polysaccharide antigen OR • Live attenuated vaccine • Modest protective effect (50-75%)

21
Q

What are non typhoidal salmonella infections

A

• ‘Food-poisoning’ salmonellas • Widespread distribution including UK • e.g. S. typhimurium, S. enteritidis • Diarrhoea, fever, vomiting, abdominal pain • Generally self-limiting but bacteraemia and
deep-seated infections may occur

22
Q

What is dengue fever?

A
Dengue fever 
• Dengue is commonest arbovirus
– 100 million cases per year and  ↑
– 25 000 deaths per year
– ~6% of returning travellers to Leicester IDU 
• 4 serotypes 
• Sub and tropical regions
– Africa, Asia, Indian SC
23
Q

Describe the symptoms of dengue fever?

A

• First infection ranges from asymptomatic to
non-specific febrile illness (“classic dengue”)
– lasts 1-5 days
– Improves 3-4 days after rash
– Supportive treatment only
• Re-infection with different serotype
– Antibody dependent enhancement
• Dengue haemorrhagic fever (children, hyper-endemic areas)
• Dengue shock syndrome

24
Q

What is myiasis?

A

• First infection ranges from asymptomatic to
non-specific febrile illness (“classic dengue”)
– lasts 1-5 days – Improves 3-4 days after rash – Supportive treatment only
• Re-infection with different serotype
– Antibody dependent enhancement
• Dengue haemorrhagic fever (children, hyper-endemic areas)
• Dengue shock syndrome

25
Q

What are some novel viruses?

A

See slide

26
Q

What is Ebola?

A

Viral haemorrhagic fever - Ebola • First described in Congo in 1976 • Filovirus • Flu-like illness with vomiting , diarrhoea
headaches, confusion, rash • Internal/external bleeding at 5-7 days • Spread by direct contact with body fluids
• Index case Dec 2013 • Initial source possibly bats • Thought to have spread
from C Africa • Treatment experimental
– Zmapp (monoclonal abs) – Antivirals
• Vaccine under
development • “Ebola free” Mar 2016

27
Q

What is zika virus

A

Zika virus • Arbovirus (flavivirus) – Aedes mosquito • Isolated in rhesus monkey, Uganda, 1952 • Outbreak 2015-present
– Americas, Caribbean, Pacific • 20% get symptoms, mild, dengue-like • Congenital microcephaly, foetal loss • Also sexual transmission • No treatment, no vaccine