Infection 8 Travel Related Infections + Neglected Tropical Diseases Flashcards
Why are neglected tropical diseases classified as neglected?
Almost absent from global health agenda
Little funding
Associated stigma + social exclusion
What questions need to be asked when a travel related infection is suspected?
Where have they been?
When were they there? Incubation time
Symptoms
Any idea on how they got the infection
Vaccinated?
Others in group unwell?
Potential diseases in that area
What are the five species of malaria which affect humans?
Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi
What is the most severe species of malaria?
Plasmodium falciparum
What is the vector for malaria?
Female Anopheles mosquito
Incubation period of malaria
Minimum 6 days
Plasmodium falciparum can be 4 weeks
Plasmodium vivax/ovale can be 1 year
What can the incubation period of plasmodium falciparum be?
4 weeks
What can the incubation period of plasmodium vivax/ovale be?
Up to 1 year
What type of organism is plasmodium?
Protozoa
Investigation needed for suspected malaria
Blood film x3 - thick + thin smears
Blood tests - FBC, U+E, LFT
CXR - chest x ray
Head CT
Management of malaria
Removal of vector - bed nets, sanitation
Drugs - artesunate, quinine (IV/PO), doxycycline, primaquine (liver related malaria)
Drugs used to treat malaria
Artesunate IV or IM
Along side - Quinine
- Doxycycline
Primaquine - liver related malaria*
What drug should be given for liver related malaria?
Primaquine
What drug shouldn’t be used for malaria from plasmodium falciparum?
Why?
Chloroquine
Widespread resistance
Who should you not give primaquine to?
G6PD patients
What is the most common species of plasmodium causing malaria?
Plasmodium falciparum
Presentation of malaria
High heart rate
Low BP
O2 sats 90%
Mild confusion
Bite/puncture mark
Hepatosplenomegaly
Vomiting + nausea
Fever
Headache
Fatigue
Sweating + chills
Dry cough
Describe the life cycle of plasmodium falciparum
1- female anopheles mosquito bites human
2- injects sporozoites
3- sporozoites infect hepatocytes
4- sporozoites mature to merozoites
5- merozoites burst out of cell + infect bloodstream
6- merozoites attack erythrocytes
7- plasmodium asexually replicate and mature in RBCs
8- merozoites burst out of erthyrocytes (schizont)
9- process repeats
What is a schizont?
Name of erythrocyte when merozoites are ready to burst out of them
Name of erythrocyte when merozoites are ready to burst out of them
Schizont
What is incubation time?
Time from when a person becomes infected until they start to see the onset of symptoms
What causes a fever?
Cytokine release
Pyrogens
What are paroxysm fever?
Fevers that occur in short bursts
How does malaria cause symptoms of haemolytic anaemia?
What is the exception?
Destruction of erthyrocytes
Plasmodium falciparum doesnt
Symptoms of haemolytic anaemia
Pallor
Jaundice
Dark coloured urine
Weakness
Dizziness confusion
What is icterus?
Yellow eye - jaundice
Prevention of malaria
Insecticide spray
Clothing that covers whole body
Mosquito nets
Avoid still lakes
Chemoprophylaxis
Why should you avoid still lakes to prevent malaria?
Anopheles mosquitos lay eyes in stagnant water
What are the categories for recurrent malaria?
- Recrudescence - parasite not killed
- Relapse- cleared merozoites, dormant hypnotises in liver are no longer dormant
- Reinfection - cured but new case
Blood test result of malaria
Low WBC, platelets + Hb
High urea, bilirubin, CRP
Why does malaria cause by plasmodium falciparum not cause haemolytic anaemia?
1- P. falciparum creates sticky protein
2- protein coats surface of RBCs
3- RBCs clump together + occlude blood vessels
4- organ ischaemia
What is Legionellosis?
Collection of conditions caused by Legionella bacteria
What is the gram stain of Legionella bacteria?
Gram negative
Most likely place of infection for Legionnaire’s disease
Examples
Where the water is at a temperature high enough to help bacteria grow
e.g. poorly maintained shower system, AC unit
Mode of transmission of Legionella bacteria
Inhalation of droplets of water
Incubation of legionnaire’s diease
2-10 days
Initial signs and symptoms of Legionnaire’s disease
Headache
Muscle/chest pain
Chills
Fever >40°
Progressive signs and symptoms of Legionnaire’s disease
Cough
Shortness of breath
Nausea
Vomiting
Diarrhoea
Confusion
Treatment of Legionnaire’s disease
Antibiotics
clarithromyin
What is the microorganism that causes Legionnaire’s disease?
Legionella pneumophilia
What other condition does Legionnaire’s disease commonly present similar signs and symptoms to?
Pneumonia
What is the characteristic image in malaria blood film?
Headphone/wedding ring
Where do plasmodium species remain dormant within the human body?
Liver
What is schistosomiasis?
Genus of flatworm
Transmission of schistosomiasis
Through unprotected skin contact in areas of fresh water contaminated with helminths released from snails
What type of microorganisms is helminths?
Parasite
Symptoms of acute schistosomiasis
Fever
Diarrhoea
Coughs
Rashes
Abnominal pain
Muscle + joint pain
Result of chronic inflammation associated with schistosomiasis
Damage due to host’s immune response
- anaemia
- cystitis
- CVS + respiratory issues
- neurological - seizures, dizziness
Diagnosis of schistosomiasis
Confirmed by finding eggs in urine or stool sample
Blood test for antibiotics
Treatment of acute schistosomiasis
Steroids - reduces inflammation
Treatment of schistosomiasis
praziquantel
What is praziquantel used for and when is it most effective (what does this mean)?
- To treat schistosomiasis
- Most effective once worms have matured
- Patients often aren’t given treatment until a number of weeks post infection
What is another name for typhoid fever?
Enteric fever
Cause of typhoid fever
Salmonella typhi
What type of microorganism is Salmonella typhi?
Bacteria
Rod shaped
Gram negative
Gram stain of Salmonella typhi
Rod shaped gram negative
Presentation of typhoid fever
Fever
Abdominal pain
Constipation
If left untreated:
Delirium
GI haemorrhage
Bowel perforation
Where is typhoid fever most common?
Where there is poor sanitation and limited access to clean water
Who are more susceptible to typhoid fever and why?
Children
Immune systems are still developing
Treatment of mild typhoid fever
IV Ceftriaxone
Cephalosporin
Azithromycin
Macrolide
At home
Treatment of serious typhoid fever
Infections of antibiotics in hospital
Vaccinations of typhoid fever
1 injections or 3 tablets
What is dengue fever cause by?
Dengue virus
Transmission of dengue virus
Mosquitoes
Presentation of dengue
Mild or asymptomatic
Intense headache
Fever
Widespread red rash
Muscle/joint pain
Treatment of dengue
No specific treatments
Normally resolves itself within a few days
Supportive treatments - paracetamol
- take plenty of fluids
Treatment of severe dengue
No treatment
Intensive care required - IV fluids
- O2 if needed
- blood transfusion
- platelet transfusion
Symptoms of severe dengue
Restlessness
Acute fever
Severe abdominal pain
Petechiae - due to low platelets
Nosebleeds
Large decrease in BP - shock
Why would aspirin and NSAIDs make dengue worse?
COX enzymes are blocked
Needed to help with clotting
