Febrile Traveller
Epidemiology
Most common diseases: diarrhoea (35% / mth travel; affects 20-50%); Resp (1.4%); Giardiasis (0.7%)
90% present within 6/12 return; 50% benign; 50% “exotic”
Most common cause of death in travellers: trauma > PE > infection
Life threats: F. malaria, typhoid fever, dengue, haemorrhagic fevers, bacterial sepsis, rickettsia, , hepatitis, leptospirosis, schistosomiasis, HIV,
amoebiasis, cholera, brucellosis
Causes of fever:
Malaria > resp > diarrhoea > dengue, Typhoid fever; RMSF; Typhus; Leptospirosis; Relapsing fever
Fever onset within 2/52 return:
Malaria, dengue (super early), typhoid fever; viral haemorrhagic fever (if Africa / S America)
Causes of Fever >7/7:
Malaria; typhoid / paratyphoid
Causes of Fever and Haemorrhage: Malaria; Dengue (DHF), Viral haemorrhagic fever
Meningococcus; Leptospirosis; Plague; Bacterial sepsis; Rickettsia; Lassa fever, Ebola; Rift Valley fever; Yellow
Fever
Causes of Splenomegaly: Malaria, dengue, typhoid
Relapsing fever, trypanosomiasis, brucellosis, kala-azar, typhus, schistosomiasis
Causes of Hepatomegaly: Malaria, typhoid, Amoebiasis, hepatitis, leptospirosis
Causes of Jaundice: Malaria, dengue, Hepatitis (A-E, EBV, Q fever); cholangitis (liver fluke); abscess (amoebic, pyogenic);, yellow fever,
leptospirosis, relapsing fever
Causes of Lymphandenopathy: Rickettsia, brucellosis, HIV, Lassa fever, leishmaniasis, EBV, CMV, toxoplasmosis, trypanosomiasis
Causes of Diarrhoea: most common illness contracted abroad (affects 20-50%); If >14/7, less likely bacterial, parasite more likely; Norfloxaxin OD
as prophylaxis in short-term high-risk patients (gastrectomy, immunocompromise, chronic illness)
Dysentry: enteroinvasive E coli, Shigella, Salmonella, Campylobacter, Entamoeba
Bacteria (>80%): salmonella, campylobacter, E coli, shigella, yersinia, cholera, clostridium perfringens / difficile; aeromonas, plesiomonas,
parahaemolyticus
Viruses (0-35%): rotavirus, adenovirus, calcivirus, astrovirus, Norwalk virus
Parasites (0-20%): giardia (most common cause for chronic diarrhoea), cryptosporidium, entamoeba histolytica, isispora
Causes of Rash: Dengue (1st + 2nd rash), rickettsial, typhus, syphilis, gonorrhoea, Ebola, brucellosis, chikungunya, HIV seroconversion
Causes of Eschar: haemorrhagic fever, Typhus, borreliosis, anthrax
Causes of skin lesions: Cutaneous larva migrans, pyodermas, pruritic arthropod-reactive dermatitis, myiasis, tungiasis
Causes of Consolidation: Legionnaries, melioidosis
Causes of Eosinophilia: Helminth infection – strongyloidiasis, filariasis, hookworm, schistosomiasis, ascariasis); Absence of eosinophilia doesn’t
exclude parasites as only occurs during invasive part of infection; Ix: 3x stools for ova, cysts, parasites; serology
Assessment
Risk
High (1/10)
Mod (1/200)
Low (1/1000)
V low (1/>1000)
Diarrhoea, URTI
Dengue fever, Chikungunya, enterovirus, giardia, hep A, malaria, salmonella, shigellosis
Amoebiasis, ascariasis, measles, mumps, enterobiasis, scabies, TB, typhoid, hep B
HIV, anthrax, Chagas disease, haemorrhagic fevers, pertussis, plague, typhus, hookworm
Regional Diseases
Africa
Central and
S America
Mexico, Caribbean
Aussie, NZ
Middle E
Europe
China, E Asia
Malaria, HIV, TB, hook/tape/roundworm, brucellosis, yellow fever, relapsing fever, schistosomiasis, tick typhus, filariasis
Malaria, relapsing fever, dengue fever, filariasis, TB, schistosomiasis,
Chagas disease, typhus
Dengue fever, hookworm, lamaria, cysticerocosis, amoebiasis
Dengue fever, Q fever, Murray valley encephalitits, Japanese Encephalitis
Hookworm, malaria, anthrax, brucellosis
Giardia, Lyme disease, tickborne encephalitis, babesiosis
Dengue fever, hookworm, malaria, strongyloidiasis, haemorrhagic fever, Japanese encephalitis
Exposures
Dirty water, unpasteurised dairy Salmonella, shigella, hepatitis, amoebiasis, schistosomiasis, brucellosis, listeriosis, TB
Shellfish
clonorchiasis, paragonimiasis, vibrios, hep A
Raw meat
trichinosis, salmonella, E coli
Veggies
fascioliasis
Animals:
Rabies, Q fever, tularemia, brucellosis, echinococcosis, antrax, plague, toxoplasmosis, herpes B
Rodent:
hantavirus, viral haemorrhagic fever, typhus, Lassa fever, plague, leptospirosis
Mosquitos:
malaria, dengue fever, chikungunya, filariasis, yellow fever
Ticks:
rickettsia, tularemia, typhus, haemorrhagic fever
Tsetse flies:
African trypanosomiasis
Fleas:
typhus, plague
Sandflies:
leishmaniasis, sandfly fever
Freshwater:
schistosomiasis, leptospirosis
Sex:
HIV, Hep B, syphilis, gonorrhoea, Chlamydia, herpe
History:
Travel history – dates, places, rural area, freshwater exposure, insect bites, sexual, mode of travel (eg. cruise ship), purpose of trip and occupation
abroad, contact with animals, swimming, drug use, tattoos / piercings
Contacts, known mozzie bite, outbreaks during stay
Time of symptom onset, medical trt abroad, injections / transfusions abroad, fever course, GI/RS/NS Sx
Incubation
periods
Investigation
Mng
Complications
Management
Pre-travel health planning:
Fitness to travel (eg. PMH, DH)
Full travel history and risk assessment
Update of routine vaccinations
Routine vaccinatiosn for travel to developing countries – hep A, typhoid
Special circumstance vaccinations – yellow fever, meningococcus, rabies, Japanese B encephalitits
Prophylacic drugs – eg. Malaria
Advice on prevention – water, STDs, nets, repellents, screens etc…
Advice on first aid kit
Advice on travel insurance
<10/7
3-7/7: dengue, yellow fever, Ebola
4-14/7: Japanese B encephalitis
Other: Flu, plague, paratyphoid, Med spotted fever, African tick-bit fever, RMSF, meningococcal disease, Rickettsia, rabies, malaria,
typhoid, anthrax, diptheria, tularaemia, typhus
10-21/7
1-2/52: amoebic dysentry, typhoid fever, giardiasis, lassa fever
2-8/52: Hep A, malaria (falciparum; >90% within 2/12)
Other: viral haemorrhagic fever, scrub typhus, Q, relapsing fever, African trypanosomiasis, Rickettsia
>21/7
4-8/52: schistosomiasis
Wks-mths: hepatitis, malaria (vivax; only 50% evident within 2/12)
Wks-yrs: strongyloides, filariasis
Others: rabies, leishmaniasis, amoebic liver abscess, TB, brucellosis; syphilis, Chagas
Bloods: as below; eosinophilia in parasites; FBC, U+E, LFT; cultures if ?salmonella; do hepatitis, dengue serology in all; do thick and thin films
Stools: ova and parasites, bacterial culture, WBC, blood, microscopy, cysts
CXR: TB, typhoid fever, malaria
ABx in trt of traveller’s diarrhoea
Norfloxacin 400mg BD PO
Ciprofloxacin 500mg BD PO
Co-trimoxazole 160mg/800mg BD PO
Azithromycin 500mg PO OD (10mg/kg in children)
Avoid loperamide if bloody diarrhoea / fever
ATN, ARF; ARDS, resp failure; cardiomyopathy, CCF; met acidosis; DIC; encephalopathy; electrolyte abnormalities; hair and nail loss
IVF guided by CVP and PCWP; inotropes; intubation and PEEP; dialysis; blood products; anti-Staph Abx; drainage of abscess, removal of FB;
consider Ig / anti-TSST-1
Malaria – RELATIVE BRADYCARDIA, LIFE THREAT
Family
P. falciparum (no periodicity): most pathogenic; esp SE Asia, PNG, Indonesia; shorter incubation period than others (ie. <2/12); assume chloroquine
resistance
P vivax (2 daily): most
common worldwide; splenic rupture more common; more likely to reactivate (hypnozoites, killed by primaquine);
onset may be delayed by months
P ovale (2 daily): more likely to reactivate (hypnozoites, killed by primaquine)
P malariae (3 daily): may have lethal nephrotoxic version
Spread
Anopheles mosquito, female; Tropical countries (W Africa, Nigeria, Solomon Islands, Ghana, PNG, SE Asia, India, S America); returning travellers;
usually sufferers have taken inadequate prophylaxis
Pathogenesis
P falciparum: infects RBC of any age  clumping and sequestration of RBC  cell lysis; anaemia, ischaemia; stimulates high levels of inflamm
mediators  incr fever
Sporozoites in saliva glands of mosquito  enter blood  invade hepatocytes (Vivax and ovale form…..
 latent hypnozoites in hepatocytes – chloroquine does not kill these, primaquine does)  multiply
 merozoites released when hepatocyte ruptures  enter RBC
 form trophozoite (Some form gameocytes than infect mosquitos again)  destroy RBC (Sx occur first here)
Sickle cell – resistant as low O2 conc and K level
Differential
diagnosis
Flu, dengue, meningitis, typhoid, pneumococcal pneumonia, hepatitis
Incubation
Days-wks
Symptoms
Most common cause of fever in traveller; may take longer for Sx if partial prophylaxis
Cyclical fevers / chills (cycle not reliable for determining species); headache, myalgia, anorexia, fatigue; CNS depression; splenomegaly; chest pain,
cough; AP+N; incr HR, decr BP, anaemia
P falciparum onset within 6/52  high parasitaemia (>100,000), severe anaemia, cerebral Sx, ARF (+oliguria), pul oedema, altered LOC, jaundice, severe
hypoG, V, acidotic
Potentially complicated: parasite >2%, jaundice, pregnancy
Other  low parasitaemia, mild anaemia, splenic rupture, nephrotic syndrome
Complications Hyperparasitaemia: >50% mortality if 10% RBC’s
Cerebral malaria: 20-50% mortality
ARF: ATN; in 10%
Black water fever: massive haemolysis and Hburia  ARF; can be life threatening
APO, severe anaemia, hypoG, spontaneous bleeding, 2Y infection
Investigation
Thick and thin blood films (rpt films Q6-12hrly for 36-48hrs before can confidently exclude; thick more sens; may be false –ives (not in falciparum); thin
allows for identification of species, more spec, parasite count determines response to trt); PCR; parasight
Rapid Ag test: >90% sens and spec, available in mins, limited availability
PCR: confirms species
Parasite LDH Ag: if falciparum; 90% sens and spec; rapid
Bloods – haemolytic anaemia (normocytic, normochromic), decr plt, mild decr WBC, incr ESR, DIC, ARF in falciparum, decr BSL, lactic acidosis (as
metabolise glucose to lactate); may be false +ive VDRL
Urine – haemoglobinuria
CXR: pul oedema
Treatment
Supportive care; admit all Falciparum and sick patients; exchange transfusion if high parasite load
Uncomplicated falciparum: Doxycycline + quinine / mefloquine / artemisinin
Vivax / ovale / malariae:
Chloroquine + primaquine PO; resistance not usually an issue
Severe malaria:
IV quinine / artesunate
Prophylaxis: prevention measures; chemoprophylaxis not 100% effective
chloroquine 250mg weekly for 1/52 before and 4/52 after
mefloquine 250mg / doxycycline / atovaguone + proguanil if chloroquine resistant area
Consult ID
Chloroquine resistance: E Africa, Thailand, Vietnam, Philippines, PNG
Prognosis
Falciparum potentially fatal in 24-48hrs; good if treated
Prophylaxis
Mefloquine, doxycycline, chloroquine, proguanil, malarone
Dengue = MOZZIE, BREAKBONE FEVER, RASH, LIFE THREAT (DHF, DSS)
Pathogen
Route of
transmission
Incubation
Epidemiology
Pathogenesis
Dengue virus  dengue fever, dengue haemorrhagic fever (esp SE Asia), dengue shock syndrome
Aedes moquito
4-10/7 (super short)
Disease of returned travellers
Dengue fever – on first infection with virus; may be subclinical
DHF / DSS: on 2nd infection; Ag/ab complexes  complement activation, consumptive coagulopathy, Incr vascular permeability
Differential
diagnosis
Symptoms
Investigations
Treatment
Prognosis
Ross river fever (also causes severe arthralgia)
High fever
Headache; conjunctival erythema, N+V, macular rash esp on face; ‘Breakbone fever’ (pain back, joints, legs)  lasts 1-7/7  settles 1-2/7 
2nd rash in 80% (maculopapular, spares palms and soles)
DHF: mostly in children <10yrs; 2nd infection in patient with immunity; due to incr vasc perm and DIC; NO myalgia or LN; hepatomegaly
DSS: in 20-30% DHF; within 2-6/7; mortality >10%; as above + circumoral cyanosis, decr BP, decr HR, delayed CRT, bleeding, pleural effusions, altered
LOC; can get myocarditis, liver failure
Serology – dengue IgM/G seroconversion
Bloods – decr plt, decr WBC, haemoconcentration, acidosis, incr Ur, incr LFT’s
CXR – pneumonia, pleural effusion
Urine: proteinuria, casts
FOB: early sign of coagulopathy
Supportive
Usually spontaneous resolution
50% mortality untreated DSS; 3% treated
Enteric fever (typhoid and paratyphoid) = salmonella – RELATIVE BRADYCARDIA, LIFE-THREAT
Pathogen
Route of
transmission
Incubation
Epidemiology
Pathogenesis
Differential
diagnosis
Symptoms
Salmonella typhi / paratyphi
Faecal - oral
5-21/7
Developing countries and returning travelers
Colonises SI, mesenteric nodes, spleen
Malaria, typhus, hepatitis, amoebic liver abscess, brucellosis, endocarditis, gastro
High fever (peaks at 7-10/7 = severely unwell), relative
bradycardia (also occurs in malaria, legionella, babesiosis), malaise, headache, myalgia,
constipation (bowel perf in severe)  diarrhoea, CNS sx, sore throat, confusion; splenohepatomegaly; rose spots (2-4mm blanching
Complications
Investigations
Treatment
Prognosis
Prophylaxis
macules in clusters)
In 30% untreated; cause 75% deaths; can involve any system
FBC: normocytic normochromic anaemia, neutropenia, incr/normal/low WCC; +ive Widal test (sens 30-90%, measures ab’s, non-spec); ELISA (95% sens
and spec)
Blood cultures: 80% +ive within 1/52, 30% +ive in 2nd wk
Stool culture: rarely +ive in 1st week; 30-60% +ive in 2nd week
Urine culture: 30% positive
CXR: pneumonia
Supportive; Amoxicillin / cipro / co-trimoxazole; May need ceftriaxone / cefotaxime in children due to resistance
Can be discharged if well; patient needs to understand infectious precautions
12-34% mortality rate untreated
Typhoid vaccine  70% protection
Rickettsial infections (typhus, RMSF, African Tick Bite Fever) = TICKS, RASH, ESCHAR
Family
G-ive rod-shaped, obligate intracellular
Spread
Vector-bourne (eg. Body lice / ticks)
Pathogenesis
Predominantly infect endothelial cells (esp lung and brain)  vasculitis, necrosis, thrombosis, rashes, organ dysfunction
Symptoms
R. prowazekii --> epidemic typhus  rash, small haemorrhages due to vascular lesion --> skin necrosis (eg. Fingers, earlobes, penis, vulva),
ecchymotic haemorrhages in brain, heart, lung etc...; pneumonia, thrombosis, vasculitis, myocarditis
Orienta tsutsugamushi --> scrub typhus; milder version of above; transient rash; necrosis rare; may be lymphadenopathy; papule  black eschar
at bite site; pneumonia, encephalitis, cardiac failure; untreated mortality 10%
R. rickettsii --> spotted fevers; haemorrhagic rash of entire body; vascular lesions cause acute necrosis, fibrin extravasation, thrombosis of small
BV's; similar perivascular inflamm response to above occuring in brain, muslce, lungs, kidneys, testes, heart
Treatment
Doxy
Viral haemorrhagic Fever = TICKS, RELATIVE BRADYCARDIA, RASH, ESCHAR
Pathogen
Incubation
Epidemiology
Symptoms
RNA zoonose viruses: Ebola, Marburg – direct contact with body secretions, inc needlestick; Africa
Lassa – less haemorrhagic and CNS features; Bolivia, Argentina, Venezuela, Brazil
Rift Valley – hepatitis, retinitis; Congo
Yellow, Omsk – mosquitos and ticks
10-21/7
Rural areas of Africa, S America, Sahara; more rare than malaria / dengue / lepto / ricketsial… More likely if contact / presents with haemorrhagic
symptoms
Requires strict isolation
Non-specific febrile illness  relative
Investigations
Treatment
Prognosis
bradycardia, conjunctivitis, pharyngitis, rash, necrosis of viscera, haemorrhagic complications
PCR / virology; decr WBC, decr plt, incr INR/APTT, DIC (esp Rift Valley, yellow fever), incr LFT’s (jaundice in yellow fever)
Barrier nursing; negative pressure room; ribavarin
Involve ID and MOH
Mortality: <1% Omsk, 25% Lassa, 90% Ebola
Schistosomiasis
Pathogen
Route of
transmission
Incubation
Epidemiology
Pathogenesis
Symptoms
Investigations
Treatment
Prognosis
Prophylaxis
Larvae penetrate intact skin from water  portal venous system  become worms  mesenteric / haemorrhoidal venules  eggs  eggs out in
faeces/urine
Snails
Africa, Middle East, Latin America
Swimmer’s itch (papular, pruritic dermatitis)
Katayama fever (fever, chills, malaise, headache, cough, AP, D, uriticaria; occasional NS Sx)
Egg deposition  haematuria, haematospermia, urinary urgency/f, dysuria, genital ulcers, prostatitis, salpingitis; rarely paraplegia, cerebral lesions
Eggs in urine / stool
Praziquantel (20mg/kg PO x2)
Notes from: Dunn