9. Travel related infections Flashcards
What are the 3 categories of incubation periods?
<10 days = acute
10-21 days = subacute
>21 days = chronic
Where should all patients with fever returning from travel be treated?
side-room of infectious disease ward (until diagnosis)
Which investigations should be performed in cases of travel-related infection?
- blood cultures x2
- malaria parasite screen x3
- FBC
- look for: anaemia/haemolysis, low platelets or lymphocytes, high eosinophils
- U and E, LFTs, CRP
- CXR
- PCR/serology based on travel Hx/symptoms
- HIV test
Name 3 examples of emerging viral respiratory diseases.
- influenza pandemics
novel coronarviruses: - SARS-CoV (severe acute respiratory syndrome)
- MERS-CoV (middle east respiratory syndrome)
Name a causative agent for viral haemorrhagic fever.
ebola virus
What type of virus is ebola?
filovirus
What are the symptoms of ebola?
flu-like illness with:
- vomiting
- diarrhoea
- headaches
- confusion
- rash
- internal/external bleeding at 5-7 days
How is ebola virus transmitted?
direct contact with body fluids
What are the treatment options for ebola?
experimental:
- Zmapp (monoclonal antibodies)
- antivirals
vaccine under dev.
How is zika virus transmitted?
- Aedes mosquito
- sexual transmission
What are the consequences of zika infection?
- 20% get mild, dengue-like symptoms
- in pregnant women causes: foetal loss or congenital microcephaly
Which infections should be considered after travel to sub-Saharan Africa?
protozoa:
1. malaria (short incubation)
long incubation:
2. trypanosomiasis (African sleeping sickness)
3. amoebic liver abscess
4. visceral leishmaniasis (esp. if swimming)
helminths:
5. acute schistosomiasis
Which investigation result indicates parasitic infection?
eosinophilia
How are schistosomes (flat worm) transmitted?
Fresh water exposure - allows cercarial stage, which reside in and are released from water snails, to penetrate intact skin of swimmers.
Name a sign of schistosomiasis.
Swimmer’s itch - localised reaction at the point of parasite penetration
What is the difference between the acute and chronic stage of schistosomiasis?
Acute stage
- involves Katayama fever: immune complex phenomenon
- illness mostly self-limiting over a few weeks
Chronic stage (if untreated) - mature adult schistosomes end up in venules of bladder and bowel and release eggs... immunological reaction to eggs may cause fibrosis of liver, bowel and bladder over many years
How is chronic schistosomiasis diagnosed?
Stool and urine culuture: presence of ova
Serological testing
How is schistosomiasis treated?
PRAZIQUANTEL
short course of oral corticosteroids to alleviate acute symptoms
What is Legionnaire’s disease?
Pneumonia caused by Legionella pneumophila serogroup 1
What type of bacteria is Legionella pneumophila?
- gram negative rod
- facultative intracellular bacteria
- aerobic
How does L. pneumophila evade immune destruction?
prevents phagolysosome fusion and replicates within macrophage
How is L. pneumophila transmitted?
aerosol inhalation (no case to case spread)
What are the signs and symptoms of Legionnaire’s disease?
Symptoms:
1. SOB and productive cough
Signs:
- fever
- low O2 saturation levels
- crackles on auscultation - pulmonary oedema
- lung consolidation on X ray
How is Legionnaire’s disease treated?
LEVOFLOXACIN (quinolone)
