15 - Travel Related Infections Flashcards
Which parts of the infection model are most significant when looking at travel infections?
Why is travel history so important and what questions should be asked?
- Any unwell travel companions /contacts?
- Pre-travel vaccinations / preventative measures?
- Healthcare exposure?
- Where have they been?
- When did the symptoms begin?
- What are the symptom/signs?
- How did they acquire it?
Identify some common regions which are associated with travel-related infections
- Sub-saharan Africa
- S.E .Asia
- S / C America
- N. Africa
- M. East S / C Asia
Identify and describe the different incubation periods for travel-related infections
What are some typical symptoms of travel-related infections?
- Jaundice
- Eosinophillia
What are some activities that lead people to get travel related infections?
Draw a table of the important features of a travel history.
What are some risk factors whilst travelling that can lead to infections, and what infections do they most commonly cause?
What is malaria?
- Malaria is a mosquito-borne infectious disease, typically transmitted through an animal vector – an infected female Anopheles mosquito
- It is the commonest imported disease in the UK
Which species of the Plasmodium parasite cause malaria in humans?
- Plasmodium falciparum (75% – mainly Africa)
- Plasmodium vivax (~20% – mainly India)
- Plasmodium ovale (~20% – mainly India)
- Plasmodium malariae
- Plasmodium knowlesii
What is the distribution of malaria like across the world?
How does a patient with malaria present when it is only mild?
- History – fever, chills & sweats (cycle every 3rd or 4th day)
- Examination – often few signs except fever (± splenomegaly)
What is the incubation period for malaria?
What are some symptoms of severe falciparum malaria?
- CVS – tachycardia, hypotension, arrhythmias
- Resp – ARDS
- GI – diarrhoea, bilirubin, deranged LFT
- CNS – confusion, fits, cerebral malaria
- Blood – thrombocytopenia, DIC
- Renal - AKI
What is the brief life cycle of the malaria parasite?
- Mosquito gut to salivary gland
- Human liver to erythrocytic to mosquito gut
What are the clinical investigations for malaria?
- CXR
What is the treatment for malaria?
How can you prevent malaria?
What is Enteric fever?
- Mainly in Asia (India) as poor sanitation
- Also S.America and Africa
What are the organisms that cause enteric fever?
- Typhoid fever: Salmonella typhi
- Paratyphoid fever: Salmonella paratyphi A, B or C
Enterobacteriaceae that are aerobic gram-negative bacillus
What is the virulence of salmonella bacteria?
- 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 signs and symptoms of enteric fever and what is the incubation period?
- 7-14 days (paratyphoid generally milder symptoms)
- Bacteraemia & sepsis
- Fever
- Headache
- Constipation
- Dry cough
- Relative bradycardia
- Abdominal discomfort
What are the complications of typhoid fever?
- Intestinal haemorrhage
- Intestinal perforation
- 10% mortality (untreated)
What are the investigations for enteric fever?
What is the treatment for enteric fever?
- Multi drug resistant (including penicillins)
- Fluoroquinolones (e.g. ciprofloxacin) may work, but increasing resistance
- Usually, IV ceftriaxone (cephalosporin) / azithromycin (macrolide) for 7-14 days
How do cephalosporins and macrolides work?
Macrolides: inhibit protein synthesis
Cephalosporins: mode of action as other β-lactam antibiotics (such as penicillins), but are less susceptible to β-lactamases. Cephalosporins disrupt the synthesis of the peptidoglycan layer forming the bacterial cell wall.
How can enteric fever be prevented?
- Food & water hygiene precautions
- Typhoid vaccine (high-risk travel & lab personnel)
- Capsular polysaccharide antigen or live attenuated vaccine
What are some non-typhoidal salmonella infections?
- Food poisoning, e.g S.typhimurium and S.enteritidis
- Diarrhoea, fever, vomiting, abdominal pain
- Mainly affect immunocompromised and develop into enteric fever in these patients a lot
What is Dengue fever?
- Dengue fever is a mosquito-borne tropical disease caused by the dengue virus
- It is commonest arbovirus and has 4 serotypes
What are the high risk areas for Dengue fever?
- Africa
- Asia
- Indian SC
How does Dengue fever present?
First infection ranges from asymptomatic to non-specific febrile illness:
- Lasts 1-5 days
- Improves 3-4 days after rash
When you see a fever and rash together after travel, what diagnoses should you be thinking about?
- Childhood viruses – measles, rubella, parvovirus
- Infectious mononucleosis (EBV / CMV)
- Acute HIV infection
- Rickettsia (spotted fever)
How can Dengue fever be treated?
- Supportive treatment (no vaccine as it can cause the disease itself)
When can complications of dengue fever arise?
- Reinfection with different serotype and this can cause an antibody dependent enhancement
- Dengue haemorrhagic fever
- Dengue shock syndrome
What is myiasis?
- Fly larva in bite wounds
What are some examples of notifiable diseases to public health?
What are some emerging diseases in the UK as a consequence of travel?
- Influenza pandemics
- Novel coronaviruses:
I. SARS
II. MERS
What is viral haemorrhagic fever?
What is Ebola and where are the high risk areas?
- Viral haemorrhagic fever caused by a filovirus, spread by direct contact with body fluids
- It presents with flu-like symptoms (+ vomiting, diarrhoea, headaches, confusion, rash) as well as internal/external bleeding at 5-7 days
- Nigeria, Guinea, Liberia, Sierra Leone
What is the treatment for Ebola?
- Antivirals
- Zmapp (monoclonal antibodies)
- Vaccine under development
What is Zika virus?
- Arbovirus (flavivirus) transmitted through the Aedes mosquito & through sexual contact
- It presents with mild dengue-like symptoms (only in 20%) and causes congenital microcephaly and/or foetal loss
- NO TREATMENT OR VACCINE
- High risk in america, caribbean and pacific
In general what tests can you do for someone who is displaying signs of a travel related infection?
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