Travel Related Infections Flashcards
1
Q
Why is the travel history important?
A
- Recognised imported diseases (rare / unknown in the UK)
- Different strains of pathogen
- Antigenically different
- Impact on protection / detection
- Antibiotic resistance - as more likely to be infected by multidrug resistant bacteria.
- Infection prevention
- On the ward
- In the lab
2
Q
How do you differentiate between what organisms it could be?
A
- Where have they been?
- Sub-saharan Africa
- S.E Asia
- S / C Ameria
- When did symptoms begin?
- Less than 10 days
- 10-21 days
- Over 21 days (chronic)
- What are the signs or symptoms?
- Resp
- GI (diarrhoea)
- Skin (rash)
- Jaundice
- CNS
- Haematological
- Eosinophilia
- How did they acquire it? (what activities did they do?)
- Food / water
- Insect / tick bite
- Swimming
- Sexual contact
- Animal contact (bite / safari)
- Recreational activities
- Any unwell travel companions? Contacts?
- Pre-travel vaccinations / preventative measures?
- Healthcare exposure?
3
Q
What are the five main species of malaria?
A
% main species of Plasmodium
- falciparum - 75% of malerial deaths. (90% of cases from Africa, 10-20% mortality)
- vivax
- ovale
- malariae
- knowlesii
Vector - female anopheles mosquito.
4
Q
Malarial History and Examination
A
- Incubation period:
- Minimum 6 days
- P, falciparum by 4 weeks
- P. vivax / ovale up to 1 year +
- History
- Fever, chills and sweats - cycle every 3rd or 4th day (not always seen, non specidic)
- Examination
- Often few sgns except fever (+/- splenomegaly)
5
Q
What are the symptoms of severe falciparum maleria?
A
- Cardiovascular
- Tachycardia
- Hypotension
- Arrhythmias
- Respiratory
- ARDS
- GIT
- Diarrhoea
- Deranged LFT’s
- Bilirubin (haemolysis)
- Renal
- Acute kidney injury
- CNS
- Confusion, fits
- Cerebral malaria
- Blood
- Low/normal WCC
- Thrombocytopenia
- DIC
- Metabolic
- Metabolic acidosis
- Hypoglycaemia
- • Secondary infection
6
Q
What is the life cycle of Maleria?
A
All down to good healthcare to prevent infection
7
Q
What investigations should be done for malaria?
A
- Malaria should be managed by an infectious disease specialist
- 3x blood films
- FBC, U&E, LFTs, glucose, coagulation
- Head CT scan if neurological symptoms
- Chest X-ray
8
Q
What is the treatment for malaria?
A
Treatment depends on species
- P. falciparum (malignant)
- Artesunate
- Quinine + doxycycline
- P. vivax, ovale, malariae (benign)
- Choroquire
- Dormant hypnozoites (liver)
- Can reoccur months - years later
- Give additional primaquine
9
Q
How do you prevent malaria?
A
- Assess risk - knowledge of risk areas
- Regular / returning travellers
- Bite prevention
- Repellant, adequate clothing, nets
- Chemoprophylaxis before travel
- Must include regular / returning travellers
- Chemoprophylaxis
- Specific to region
- Start before and continure after return (generally 4 weeks)
10
Q
Typhoid and paratyphoid
A
- Also known as enteric fever
- Mainly asia (also Africa and S america) - poor sanitation
- 21 million cases per pear, mainly children
- UL: travel-related
- 500 cases/yr (mainly sub-indian continent)
- Mechanism of infection
- Faecan-oral route from contaminated food / water
- Source is cases or carriers (himan pathogen only)
11
Q
Salmonella - the organism.
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)
12
Q
What are the signs and symptoms of enteric fever?
A
- Systemic disease (bacteraemia / sepsis)
- Incubation period: 7-14 days
- Relatice bradycardia
- Complications
- Intestinal haemirrhage and perforation; seeding
- 10% mortality
- Chronic carrier state 1-5%
- Paratyphoid: generally milder
13
Q
What are the investigations conducted for enteric fever?
A
- Moderate anaemia
- Lymphopaenia
- Raised LFTs (transaminase and bilirubin)
- Culture
- Blood (+ve in 40-80%)
- Faeces, bone marrow
- Serology (antibody detection) not reliable
14
Q
What are the treatments for enteric fever?
A
- Multi-drug resisant (inc. penicillins)
- Fluroquinolones (e.g. ciprofloxacin) may work, but increasing resistance
- Usually treated with IV ceftriaxone (cephalosporin) or azithromycin (macrolide) for 7-14 days
15
Q
How do you prevent enteric fever?
A
- Food and water hygiene precautions
- Typhoid vaccine
- High-rsh travel
- Laboratory personnel
- Capsular polysaccharide antigen OR
- Live attenuated vaccine
- Modest protective effect (50-75%)
