Travel Related Infection Flashcards
Factors that can make travellers vulnerable to infection
Temptation to take risks away from home - food - water - animals - sex Different epidemiology of some diseases - HIV, TB, Polio, diptheria Incomplete understanding of health hazards Stress of travel Refugees - deprevation - malnutrition - disease - injury
Climate or environment related health problems
Sunburn Heat exhaustion/Heat stroke Fungal infections Bacterial skin infections Cold injury Altitude sickness
Infections that are controllable by sanitation
Traveller's diarrhoea Hep A or E Typhoid Food poisoning Cholera
Water related infections include
Schistosomiasis
Leptospirosis
Liver flukes
What is malaria’s vector?
Female anopheles mosquito
What is dengue fever vector?
Mosquitos
What is leishmaniasis’s vector?
Sand flies
Definition of malaria
Parasitic infection of red blood cells
Malaria life cycle
- mosquito bite
- sporozoites injected into bloodstream which rapidly migrate to liver cells
- multiple in liver cells to merozoites
- these go to red cells and replicate and make them burst
- A cycle of replication is made
- Male and female gameotocytes replicate inside the mosquitos gut
5 species of malaria
plasmodium falciparum (serious) plasmodium vivax plasmodium ovale plasmodium malariae plasmodium knowlesi
Presentation of malaria
Fever and rigors Aching bones Abdominal pain Headache Dysuria Frequency Sore throat Cough Majority no signs until established disease - splenomegaly - hepatomegaly - jaundice
Complications of malaria
Cerebral malaria (encephalopathy) Blackwater fever Pulmonary oedema Jaundice Severe anaemia Algid malaria
Definition of algid malaria
Gram -ve septicaemia
Investigations of malaria
Thick and thin blood films
Quantative buffy coat (QBC)
Rapid antigen tests
Complicated malaria means one or more of…..
Impaired consciousness/seizures
Hypoglycaemia
Parasite count >_2%
haemoglobin
Treatment of uncomplicated P. Falciparum malaria
Rimamet, euratesim and malarone for 3 days OR
Quinine 7 days plus oral doxycycline/clindamycin
Treatment of complicated or severe P. falciparum malaria
IV quinine plus oral doxycycline/clindamycin
Treatment of benign species of malaria
Cholorqine 3 days
Riamet 3 days
Add primaquine (14 days) in vivax + ovale to eradicate liver hypnozoites
Malaria control measures
Mosquito breeding sites - drainage of standing water Larvacides Mosquitos killing sprays (DDT) Human behaviour - DDT - bed nets - mesh windows
Causative organisms of typhoid (enteric) fever
Salmonella typhi
Salmonella paratyphi
Causes of typhoid fever
Poor sanitation
Unclean drinking water
How is typhoid fever transmitted?
Faecal-oral route
Incubation time for typhoid fever
7 days - 4 weeks
Presentation of typhoid fever
1st week - fever - headache - abdominal discomfort - constipation - dry cough - relative bradycardia - neutrophilia - confusion 2nd week - fever peaks 7-10 days - rose spots - diarrhoea begins - tachycardia - neutropenia 3rd week (complications) - intestinal bleeding - perforation - peritonism - metastatic infections 4th week (recovery) - 10-15% relapse
Investigations for typhoid fever
Blood culture
urine culture
stool culture
Bone marrow culture
Treatment of typhoid fever
uncomplicated, Asian acquired
- oral azithromycin
Complicated/concerning
- IV ceftriaxone
What is the commonest human arbovirus infection?
Dengue fever
Where is dengue fever found?
South of the equator - tropical conditions
Presentation of dengue fever
Sudden fever Severe headache, retro-orbital pain Severe myalgia and arthralgia Macular/maculopapular rash haemorrhagic - petechiae, purpura
Investigations for dengue fever
Clinical - thrombocytopenia - leucopenia - elevated transaminases - positive tourniquet test PCR Serology
Treatment for dengue fever
No treatment
Complications of dengue fever
Dengue haemorrhagic fever (DHF)
Dengue shock syndrome (DSS)
Treatment of complications of dengue fever
IV fluids
Fresh frozen plasma
Platelets
Prevention of dengue fever
Avoid bites New vaccine (degvaxia)
Where is schistosomiasis found?
Fresh water and fresh water snails
Types of Schistosomiasis
S. Haematobium
S. mansoni
S. japonicum
Life cycle of schistosomiasis
- Eggs in faeces and urine
- Eggs hatch releasing miracidia
- Miracidia penetrate snail tissue
- Sporocysts in snail (successive generation)
- Cercarial released by snail into water and free swimming
- Penetrate skin
- Cercarial lose tails during penetration and become schistosomulae
- circulation
- Migrate to portal circulation in liver and mature into adults
- Paired adult worms migrate to
- mesenteric venules of bowels/rectum (layering eggs that circulate to the liver and shred in stools)
- venous plexus of the bladder - excreted out in faeces/urine (eggs)
Presentation of schistosomiasis
Swimmers itch in first few hours - clears after 24-48 hours Invasive stage (after 24 hours) - cough - abdominal discomfort - splenomegaly - eosinophilia Katayama fever (After 15-20 days) - prostate - fever - urticaria - lymphadenopathy - splenomegaly - diarrhoea - eosinophilia Acute disease (6-8 weeks) - eggs deposited in bowel (dysentery) or bladder (haematuria)
Investigations for schistosomiasis
Clinical
Antibody tests
Ova in stools and urine
Rectal snip
Treatment for schistosomiasis
Praziquantel 2 doses 6 hours apart
Prednisolone if severe
Presentation of Rickettsiosis/tick typhus
Tick bite eschar Maculopapular rash Abrupt onset swinging fever Headache Confusion Endovasculitis Rash (macular, petechial) bleeding
Diagnosis of ricketsiosis/tick typhus
Clinical features
Serology
Treatment of tick typhus/rickettsiosis
Tetracycline
Maximum incubation period of viral haemorrhagic fevers
3 weeks
Examples of viral haemorrhagic fever infections
Ebola
Lassa fever
Marburg disease
Treatment of viral haemorrhagic fevers
Supportive
Transmission of zika virus
daytime-biting aedes mosquito
sexual contact
blood transfusion
What is the Zika virus related to?
Dengue
Yellow fever
Jap B encephalitis
West nile virus
Presentation of zika virus
No or mild symptoms - headache - rash - fever - malaise - conjunctivitis - joint pains (like dengue) In pregnancy - microencephaly and other neurological problems Guillian barre syndrome
Treatment of the zika virus
No treatment
Investigations of a returning traveller with a fever
FBC Malaria films LFTs Stool microscopy/culture Urinalysis + culture Blood cultures CXR Specific tests for specific diseases as indicated
If a rash and fever on examination, what can this indicated in a returning traveller?
Typhoid
Typhus
Dengue
What can jaundice and fever on examination of a returning traveller indicate?
Leishmania
Trypanosomiasis
What can liver signs and fever suggest in a returning traveler?
Malaria
Typhoid
Ameobic abscess
What can spleen signs and fever suggest in a returning traveler?
Visceral leishmaniasis
Typhoid
Malaria
Treatment of non falciparum acute malaria
Chloroquine
Most common non falciparum malaria
Plasmodium vivax
What is yellow fever spread by?
Aedes mosquito
Incubation of yellow fever
2 - 14 days
Presentation of yellow fever
Mild flu like illness lasting < 1 week
Sudden onset high fever, rigours, N + V, bradycardia
Brief remission
Then jaundice, haematemesis, oliguria
What may be seen in hepatocytes in yellow fever?
Councilman bodies (inclusion bodies)
Transmission of typhoid
Faecal oral (and contaminated food and water)
Presentation of typhoid
Headache Fever Arthrlagia Relative bradycardia Abdominal pain and distension Rose spots (trunk in 40%) - more common in parathyroid
Complications of typhoid
Osteomyelitis GI bleed / perforation Meningitis Cholecystitis Chronic carriage (1% - more likely if adult females)
Treatment of amoebiasis
Metronidazole
