Travel Related Infction Flashcards
How does increasing lglobal travel lead to infection
• Exotic destinations • Underlying medical conditions • War / natural disasters • Migration of populations • Emerging infections • Non-infectious problems – Accidents
What person factors should be considered in travel related infections
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
What are some significant pathogens in
Bacteria - rickettsia/spirochaete (vectors)
Fungus - yeast, mound
Parasite - Protozoa, helminth (vectors)
Why is the travel history important?
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
What factors should be taken as the history is taken?
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
What are specific risk factors for travel related infection
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
What are other aspects o travel history
- Any unwell travel companions /contacts?
- Pre-travel vaccinations / preventative measures?
- Healthcare exposure?
What are the 5 main species of plasmodium and what transmits it
• 5 main species of Plasmodium – falciparum – vivax – ovale – malariae – knowlesii Concentrate on first 2 • Vector - female Anopheles mosquito
Describe the number of cases of malaria per year
• 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)
Describe the symprtoms of malaria
Central - headache Systemic - fever Muscular - fatigue, pain Back - pain Skin - chills, sweating Respiratory - dry couch Spleen - enlarge Stomach - nausea, vomiting
Describe the history and examination of malaria
• Incubation period: – Minimum 6 days – P. falciparum: by 4 weeks – P. vivax/ovale: up to 1 year+ • History – Fever chills & sweats - cycle every 3rd or 4th day • Examination – Often few signs except fever (+/- splenomegaly)
Describe the symptoms of severe falciparum malaria
See slid
Describe the malaria life cycle
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
Describe the investigations and treatment of malaria
• 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
Describe typhoid/paratyphoid
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)
Describe the salmonella organisms
• 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)
What are the symptoms and signs off enteric fever
Enteric fever - symptoms & signs • Systemic disease (bacteraemia/sepsis) • Incubation period: 7-14 days • Fever, headache, abdominal discomfort, dry cough • Relative bradycardia • Complications – intestinal haemorrhage & perforation; seeding – 10% mortality (untreated) – Chronic carrier state 1-5% • Paratyphoid: generally milder
Describe the investigations for enteric fever
• Moderate anaemia • Lymphopaenia • Raised LFTs (transaminase & bilirubin) • Culture
– Blood (+ve in 40-80%)
– Faeces, bone marrow • Serology (antibody detection) not reliable
Describe the reatment for enteric fever
• 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
Describe the prevention for enteric fever
• Food & water hygiene precautions • Typhoid vaccine
– High-risk travel
– Laboratory personnel • Capsular polysaccharide antigen OR • Live attenuated vaccine • Modest protective effect (50-75%)
What are non typhoidal salmonella infections
• ‘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
What is dengue fever?
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
Describe the symptoms of dengue fever?
• 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
What is myiasis?
• 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
