Week 5 - Travel related infections Flashcards
What would an FBC of malaria show?
- Decreased Hb
- Decreased WBC
- Decreased platelet count
Why does malaria affect the liver?
- Increased breakdown of RBCs
- Liver cannot cope with increased demand and jaundice ensues followed by liver damage
What is the infectious cause of malaria?
-Plasmodium of which there are 4 species: P.falciparum P.Vivax P.Ovale P.malariae
What is the vector for malaria?
-Female anopheles mosquito
Does malaria require isolation?
-No, there is no case-case spread
Where is malaria common?
- Africa (bar the south)
- India
- S.America
How long is the incubation period of malaria?
-1-3 weeks
Which plasmodium species is most severe?
-P.falciparum
What are the complications of p.falciparum malaria?
- CVS complications -> tachy, hypotension, arrhythmias
- Resp -> ARDS
- GIT -> jaundice and diarrhoea
- Renal -> AKI
Describe the pathogenesis of malaria
- Plasmodium in mosquito matures into sporozoite and takes a blood meal injecting parasite
- Parasite infects liver cells and forms a schizont which rupures and enters bloodstream
- Infects RBC and matures resulting in lysis of RBC and infects another
What are the investigations of malaria is suspected?
- Contact infectious disease physician
- Blood smear x 3
- FBCs, U+Es, LFTs, glucose
- Head CT if CNS problems
- CXR
What are the treatments of malaria?
- Treatment is species specific
- P,falciparum -> quinine
- P.vivax, ovale or malariae -> primaquine and chloroquine
How is malaria prevented?
- Knowledge of at risk areas via CDC
- Bite prevention -> covered clothes etc
- Chemoprophylaxis
Why is history so important in infectious disease?
- Recognise imported diseases
- Infection prevetion
- Different strains of pathogen have different virulence/resistance
What is enteric fever?
-Typhoid or paratyphoid
How does enteric fever present?
-Constipation, severe cramps, vomiting, bacteraemia, abdomen tenderness, splenomegaly, temp, low BP
What are the features of FBC in enteric fever?
- Decreased WBC
- Decreased Hb
What are the features of LFTs in enteric fever?
- Increased ALT
- Increased CRP
What is the infectious agent of enteric fever?
- Salmonella Typhi
- Salmonella Paratyphi A, B or C
In what countries in enteric fever common and why?
-Africa, Asia and S.america due to poor sanitation
Who does enteric fever mainly affect?
-Children
What is the mechanism of infection of enteric fever?
-Faecal-oral from contaminated food/water
What is the gram status of salmonella?
-Gram negative bacilli
What gives salmonella typhi its virulence?
-Endotoxin, VI antigen, invasins and fimbrae
Where specifically in the GI tract does salmonella typhi invade?
-Payers patches
What is the incubation period of salmonella typhi?
-7-14 days
What is the firstline treatment for salmonella?
-Ceftriaxone or macrolide
How is enteric fever prevented?
- Food and water hygeine
- Precautions
- Vaccines
What are the serotypes of influenzae?
-A, B C
How are influenzae viruses spread?
-Cough/sneeze
What is the incubation period for influenzae?
-2 days
What is the presentation of influenzae?
-Headache, sore throat, fever, muscle ache, cough
Does influenzae require treatment?
-No, it is self-limiting
What are possible complications of influenzae?
- Pneumonia
- Sinusitis
How can you prevent influenzae?
- Frequent hand washing
- Vaccinations of elderly and at risk
Why do you have to vaccinate from influenzae yearly?
-Rapidly evolving virus so new strain year on year
What to viral peptides are responsible for influenzae virulence?
-Haemogluttin and Neurominadase
What is antigenic drift?
-Small mutations which occur continually over time from person-person
What is antigenic shift?
-Complete change in viral protein composition
Describe the presentation of legionnaires disease
-Fever, SoB, Productive cough, decreased O2 satsm Increased RR, increased HR (SIRS)
What investigations would you do for legionella?
-CXR, sputum sample, blood culture, FBC, U+E,
Describe the gram status of legionella pneumophilia
-Gram negative bacilli (flagellated)
How is legionella transmitted?
- Airborne
- Contaminated water droplets
What type of cells does legionella infect?
-Type 2 pneumocytes
What is the first line treatment for legionella?
-Erythromycin
Name some causes of travellers diarrhoea
- Norovirus
- E.coli
- Campylobactor
- Salmonella
- Shigella
- rotavirus
- Vibrocholera
What is icterus?
-Yellow sclera
Name the travel-related infection associated with a confluent macular rash
-Dengue fever
How would you diagnose dengue fever?
-PCR and serology
Name a travel related infections associated with lava
-Myiasis (bot fly)
What is dysentry?
-Blood and mucus in stool
What are some important questions you would ask a patient to elicit travel history?
- Where have you been and for how long?
- When did you return?
- When did your symptoms start in relation to your return?
- Is your travel companion ill?
- Did you do any recreational activities?
- Did you take any precautions before going away? (vaccinations)
Describe the common presentation of malaria
- Fever and chills
- Muscle weakness,myalgia and fatigue
- Shaking
- Headache and syncope
- Decreased BP, increased HR, Decreased Sats
