What are the relevant patient factors to travel related infections?
Calendar and relative time
Why is a patient's travel history important?
Imported diseases that are rare or unkown in the UK can occur, Infection DDx must be broadened to include infections endemic to areas travelled recently by patient
Different strains of pathogen are/have potentially:
Impacting on protection and detection
Antibiotic resistance differences
Guides necessary ward and lab based infection prevention
What are the key aspects of a patients travel history?
Where? (Be exact)
How (Direct or via?)
Specific risks (including sexual contact)
Preventative measures taken (E.g. Doxycycline)
What are the 4 main species of micro-organism that can cause malaria?
escribe the spread of malaria
Female mosquitos are the vector
No case to case spread
Where does malaria occur?
Africa, Asia, Middle east, South and Central America
Describe a typical malaria history
Fatigue and Malaise
Arthralgia (joint pain)
Fever, Chills and Sweats which cycle every 3rd or 4th day
All occuring 1-3 wks after bite (incubation period)
What might be the common findings of an examination of patient with malaria?
Resp distress (metabolic acidosis, pulm oedema)
Who is responsible for treatment of malaria?
Infectious disease physician
Describe malaria management
Blood smear to detect parasites
FBC, Urea and Electrolytes, LFTs, Glucose
Head CT if CNS symptoms
Treatment is species dependent:
- P. falciparum - quinine or artemisinin
- P. vivax, ovale, malariae - chloroquinine +/- primaquine
Describe a cycle of Malaria transmission/infection beginning from a mosquito biting an infected human
Mosquito acts as vector, infected blood passes into the mosquito gut and can be passed on via the mosquitos saliva
A mosiquto bites a human and the malarial parasite enters the blood through mosquito saliva
Parasite takes root in the liver (Exo-erythrocytic phase)
Parasite is released into the blood (Erythrocytic phase)
Mosquito can bite newl infected human and further pass it on
Outline the prevention of malaria
- Knowlegde of risk areas for regular or returning travellers
- Repellant, aqequate clothing, nets
- Chemoprophylaxis before travel
- Specific to region
Stats and continues before/after return
What is enteric fever?
General term for Typhoid and Paratyphoid fever
Describe the epidemiology of enteric fever worldwide and in the UK
Widespread in areas with poor sanitation
21 million cases per year, mostly children
500 cases/yr (travel related - mainly India)
What is the mechanism of infection of enteric fever?
Source is cases or carriers only
What is the causative organism for enteric fever?
Salmonella enterica serotypes
Commonly Salmonella typhii/paratyphii A, B or C
Aerobic gram negative rods
What are the virulence factors of Salmonella enterica subsp. that commonly cause enteric fever?
Gram negative endotoxin (VI antigen)
Invasin (to allow intracellular growth)
Fimbriae (small hairlike processes) allow adherence to ileal peyer's patches
What are the symptoms and signs of enteric fever?
Systemic disease w/ fever and headache
Complications can include haemorrhage and perforation of bowel
What investigation might be performed in a patient with suspected enteric fever?
What would be found in a patient with enteric fever?
FBC, WBCC, Urea and Electrolytes, LFTs, Blood and stool culture
Bacteria in blood and stool culture (S. Enterica subsp.)
What is the current treatment for enteric fever?
Ceftriaxone or azithromycin for 7-14 days
Describe the preventative measures for enteric fever
Food and water hygiene precautions (boil water etc)
Used for high risk travel and lab personnel
VI capsular polysaccharide antigen or live attenuated virus
Apart from enteric fever, what other common disease is caused by salmonella spp.?
Give common causative organisms, symptoms and complications
Widespread distribution including UK (non-travel related)
Commonly caused by S. typhirium/enteritidis
generally self limiting but bacteriaemia and deep seated infection may occur
What is zoonosis?
Any process whereby an infectious disease is transmitted from animal to human
Give an example of a zoonosis disease
Include the common causative organisms and it's distribution worldwide
Brucella abortus (cattle) and B. melintensis (goats and sheep)
Gram negative coccobascillus
With regards to brucellosis describe the:
Through skin breaks or the GI tract (Milk)
Non specific, febrile (undulant fever, rising and falling)
Generally from blood culture
Doxycycline and rifampicin
Why is travel history important in a patient that potentially has a severe/high risk disease?
Assessment of travel guides possible diagnosis
Also allows us to assess possibility of high risk infection being present
What precautions might be taken with someone with a suspected high risk of a travel related infection?
Requirement to consider isolation
Additional protections afforded to clinicians/lab staff handling high risk specimens
Give an example of two types of novel emergent viruses that caused pandemics
E.g. H1N1 swine flu in 2009
E.g. SARS-CoV in 2003 (severe acute respiratory syndrome)
Give examples of viruses, vectors and diseases that cause haemorrhagic fevers
Your examples may vary
Filoviridae - Bat - Ebola haemorrhagic fever
Flaviviridae - Mosquito - Dengue and Yellow haemorrhagic fever
What are the symptoms of Ebola?
Internal/external bleeding at 5-7 days