++
Most will present within 2 weeks except HIV seroconversion infection.
Common infections encountered are dengue fever, giardiasis, hepatitis A and B, gonorrhoea or Chlamydia trachomatis, malaria and helminthic infestations.
An important non-infection problem requiring vigilance is deep venous thrombosis (DVT) and thromboembolism.
The asymptomatic traveller may present for advice about exposure (without illness) or about an illness acquired such as rabies, malaria, schistosomiasis and STIs.
++
Red flags in the returned traveller
+++
Gastrointestinal symptoms
++
Stool microscopy and culture
Look for and treat associated helminthic infestation (e.g. roundworms, hookworms)
+++
Moderate or prolonged (>3 weeks) diarrhoea
++
Usually due to Giardia lamblia, Entamoeba histolytica, Campylobacter jejuni (especially South-East Asia), Salmonella, Yersinia entero-colitica or Cryptosporidium.2
++
Stool examination (three fresh specimens):
– microscopy
– wet preparation
– culture
Faecal Multiplex PCR (if available)
Treat pathogen (see guidelines under diarrhoea in CHAPTERS 14 and 44)
++
Non-pathogens such as Escherichia coli and Endolimax nana are often reported but do not treat specifically.
++
Note: Consider exotic causes such as schistosomiasis, strongyloidiasis and ciguatera in unusual chronic post-travel ‘gastroenteritis’.
+++
Persistent abdominal discomfort
++
This common syndrome includes bloating, intestinal hurry and borborygmi, and often follows an episode of diarrhoea. Usually no pathogens are found on stool examination. However, giardiasis can be difficult to detect and an empirical course of tinidazole (2 g statim) is worthwhile. Any persistent problem then is a type of postinfective bowel dysfunction or irritable bowel. Reassurance is important.
+++
Rash/other skin lesions
++
Maculopapular: consider dengue, HIV, typhus, syphilis, arbovirus infections, leptospirosis, Q fever
Petechiae: viral haemorrhagic fevers, leptospirosis, dengue
Rose spots: typhoid
Eschar: typhus (tick and scrub), anthrax
Chancre: African trypanosomiasis, syphilis
++
Causes range from mild viral infections to potentially fatal cerebral malaria (see TABLE 15.1) and meningococcal septicaemia.
An Australian study of fever in returned travellers3 revealed the most common diagnosis was malaria (27%) followed by respiratory tract infection (24%), gastroenteritis (14%), dengue fever (8%) and bacterial pneumonia (6%). The commonness of malaria was supported by results from the GeoSentinel Surveillance Network.4
The common serious causes are malaria, typhoid, hepatitis (especially A and B), dengue fever and amoebiasis.
Most deaths from malaria have occurred after at least 3 or 4 days of symptoms that may be mild. Death can occur within 24 hours. Factors responsible for death from malaria include delayed presentation, missed or delayed diagnosis (most cases), no chemoprophylaxis and old age.
Refer immediately to a specialist unit if the patient is unwell.
Be vigilant for meningitis and encephalitis.
Be vigilant for amoebiasis—can present with a toxic megacolon, especially if antimotility drugs are given.
If well but febrile, first-line screening tests:
Refer immediately if malaria is proven or if fever persists after a further 24 hours.
++
++
++
++
Incubation period: P. falciparum 7–14 days; others 12–40 days
Most present within 2 months of return
Can present up to 2 or more years
Can masquerade as several other illnesses
++
++
High fever, chills, rigor, sweating, headache
Usually abrupt onset
Can have atypical presentations (e.g. diarrhoea, abdominal pain, cough)
++
Beware of modified infection.
Must treat immediately. Delay may mean death.
Typical relapsing patterns often absent.
Thick smear allows detection of parasites (some laboratories are poorly skilled with thick films).
Thin smear helps diagnose malaria type.
If index of suspicion is high, repeat the smear (‘No evidence of malaria’ = 3 negative daily thick films). Newer tests (e.g. polymerase chain reaction [PCR] tests and immune chromatographic test [ICT] card tests for PFM) show promise. Cerebral malaria and blackwater fever are severe and dramatic. The Para check V test (a desktop test) is accurate and needs to be positive before prescribing artemether in some areas.
++
Admit to hospital with infectious disease expertise. Rule out G6PD deficiency
Supportive measures, including fluid replacement
Avoid the same drugs used for prophylaxis
P. vivax, P. ovale, P. malariae5
artemether + lumefantrine 20 mg + 120 mg (Riamet)
4 tablets with food at 0, 8, 24, 36, 48, 60 hours (i.e. 24 tablets) in 60 hours
+
primaquine dose by weight to achieve a total dose of 6 mg/kg
P. falciparum5 uncomplicated
Riamet (as above)
or
atovaquone + progunail
or
quinine sulphate 600 mg (o) 8 hourly, 7 days +
doxycycline 100 mg (o) 12 hourly, 7 days
or
clindamycin 300 mg (o) tds, 7 days (children, pregnancy)
complicated (severe):
artesunate 2.4 mg/kg IV statim, 12 hours, 24 hours, then once daily until oral therapy (Riamet) is possible
or
quinine dihydrochloride 20 mg/kg up to 1.4 g IV (over 4 hours) then after 4-hour gap 7 mg/kg IV 8 hourly until improved (ECG/cardiac monitoring)
then
quinine (o) 7 days
Note: Check for hypoglycaemia. Beware if antimalarial use in previous 48 hours.
++
Incubation period 10–14 days
++
Insidious onset
Headache prominent
Dry cough
Fever gradually increases in ‘stepladder’ manner over 4 days or so
Abdominal pain and constipation (early)
Diarrhoea (pea soup) and rash—rose spots (late)
± splenomegaly
++
DxT ‘stepladder’ fever + abdominal pain + relative bradycardia ➜ typhoid (early)
++
++
++
Incubation period a few hours–5 days
++
Subclinical
Mild, uncomplicated episode of diarrhoea
Fulminant lethal form with severe water and electrolyte depletion, intense thirst, oliguria, weakness, sunken eyes and eventually collapse
++
DxT fever + vomiting + abrupt onset ‘rice water’ diarrhoea ➜ cholera
++
Stool microscopy and culture (Vibrio cholerae)
++
+++
VIRAL HAEMORRHAGIC FEVERS
++
These include: yellow fever, Lassa fever, etc., plus dengue fever and chikungunya.
++
Milder cases may present with flu-like symptoms and relative bradycardia (Faget's sign) and albuminuria. Severe cases experience these symptoms with abrupt fever then prostration, jaundice and abnormal bleeding from the gums and possibly haematemesis. Diagnosis is by ELISA testing.
++
DxT fever + bradycardia + jaundice + bleeding ➜ yellow fever
+++
Lassa fever, Ebola virus, Marburg virus, Hanta virus
++
These rare but deadly tropical diseases usually commence with a flu-like illness, gastrointestinal symptoms with thrombocytopenia, anaemia and, if severe, findings consistent with disseminated intravascular coagulation leading to bleeding and possibly shock and frank haemorrhage. Hanta virus tends to cause respiratory symptoms, including cough, progressing to respiratory difficulty. Seek urgent expert help.
++
Incubation period: 2–16 days
Transmission: direct body contact (body fluids, esp. blood, vomit from affected or dead person), infected animals, contaminated objects (needles, medical equipment)
Early symptoms: constitutional (fever, malaise, headache), upper respiratory (flu-like, cough, etc.), abdominal (pain, nausea, vomiting, diarrhoea)
May progress to severe symptoms as above then multiorgan failure
Diagnosis: PCR, histopathology
Treatment is supportive, esp. IV fluids
++
Also known as ‘breakbone’ fever, it is widespread in the south-east Pacific and endemic in Queensland. A returned traveller with myalgia and fever <39°C is more likely to have dengue than malaria. It is commonly misdiagnosed.
++
Mosquito-borne (Aedes aegypti) viral infection
Incubation period 5–6 days
Abrupt onset fever, malaise, headache, nausea, pain behind eyes, severe backache, prostration
-
Sore throat
Severe aching of muscles and joints
Fever subsides for about 2 days, then returns
Maculopapular rubelliform rash on limbs → trunk (hand pressure for 30 seconds causes blanching)
Petechial rash common (even in absence of thrombocytopenia)
Generalised erythema with ‘islands of sparing’
± Diarrhoea
The rare haemorrhagic form is very severe; may present with shock, which is usually fatal
Later severe fatigue and depression (prone to suicide)
++
Note: A large-scale survey of dengue patients showed the symptoms as fever 100%, myalgia 79%, rash 74%, headache 68%, nausea 37%.
++
DxT fever + severe aching (especially headache) + rash ➜ dengue fever
++
++
Symptomatic with rest, fluids and analgesics (paracetamol). Avoid antibiotics, aspirin, NSAIDs and corticosteroids
++
++
Also transmitted by Aedes aegypti, it is more common in Central and South America. Most infections are asymptomatic but common symptoms are fever, rash, arthralgia and conjunctivitis with a dengue-like syndrome. Can cause a Guillain–Barré-like syndrome or cerebral damage (microcephaly) in infants of infected mothers. Diagnosis is confirmed by serology and PCR. Treatment is symptomatic.
++
This is an alpha-viral mosquito-borne infection with a similar clinical picture to dengue fever; it can cause haemorrhagic fever. It is encountered in tropical South-East Asia, Indian Ocean islands and parts of Africa.
++
++
Encephalitis presents with fever, nausea and vomiting then progressing to stupor, coma and convulsions. Mosquito-borne cases include Japanese B encephalitis and West Nile fever.
++
Consider mosquito-borne encephalitis and meningococcal meningitis in a patient presenting with headache, fever and malaise before neurological symptoms such as delirium, convulsions and coma develop.
++
This serious disease with a high mortality is caused by the Gram-negative bacillus Burkholderia pseudomallei, a soil saprophyte that infects humans mainly by penetrating through skin wounds, especially abrasions. It is mostly acquired while wading in rice paddies. It is mainly a disease of third world countries and occurs between 20° North and 20° South of the equator, mainly in South-East Asia and including northern Australia. It may manifest as a focal infection or as septicaemia with abscesses in the lung, kidney, skin, liver or spleen. It is called the ‘Vietnamese time bomb’ because it can present years after the initial infection, as seen in Vietnamese war veterans.
++
++
DxT fever + pneumonia + myalgia ➜ melioidosis
++
++
Ceftazidime 2 g IV, 6 hourly
Meropenem 1 g IV, 6 hourly
Imipenem 1 g IV, 6 hourly
All for at least 14 days, followed by oral cotrimoxazole ± doxycycline bd + folic acid for 3 months
++
++
Plague (Black Death), which is caused by the Gram-negative bacterium Yersinia pestis, is endemic in parts of Asia, Africa and the Americas. It has been presumed to be transmitted by the flea: ‘the flea bites the infected rat and then bites the human’, but spread from person to person is now considered more likely.
++
There are basically two forms:
++
bubonic plague—painful suppurating inguinal or axillary lymphadenitis (buboes) (see FIG. 15.2)
pneumonic plague—flu-like symptoms with haemoptysis, septicaemia and a fatal haemorrhagic illness (± buboes)
++
++
There is a rapid onset of high fever and prostration with black patches of skin due to subcutaneous haemorrhage.
++
++
++
Rabies is a rhabdovirus acquired by bites from an infected mammal, for example, a dog, cat, monkey, fox or bat.
++
Prodromal symptoms can include malaise, headache, abnormal behaviour including agitation and fever. It progresses to either paralytic ‘dumb rabies’ or encephalitic ‘furious rabies’, which involves excessive salivation and excruciating spasms of the pharyngeal muscles on drinking water (in particular). The patient is terrified of drinking water despite a great thirst (hydrophobia).
++
DxT painful/itchy bite + agitation + hydrophobia ➜ rabies
++
++
++
Wash the wound immediately then clean it. Administer rabies vaccine (if unimmunised) and rabies immune immunoglobulin ASAP (within 48 hours).
++
This is a type of food poisoning caused by eating tropical fish, especially large coral trout and large cod, caught in tropical waters (e.g. the Caribbean and tropical Pacific). The problem is caused by a type of poison that concentrates in the fish after they feed on certain micro-organisms around reefs. Ciguatera poisoning presents within hours as a bout of ‘gastroenteritis’ (vomiting, diarrhoea and stomach pains) and then symptoms affecting the nervous system, such as muscle aching and weakness, paraesthesia and burning sensations of the skin, particularly of the fingers and lips. There is no cure for the problem but it can be treated with IV fluids and possibly mannitol infusion or gammaglobulin. It is unwise to eat large predatory reef fish, especially their offal (mainly the liver).
+++
Hansen's disease (leprosy)
++
Hansen's disease (Gerhard Hansen, 1869) is caused by the acid-fast bacillus Mycobacterium leprae. It is a disorder of tropical and warm temperate regions, especially South-East Asia. It is considered to be transmitted by nasal secretions with an incubation period of 2–6 years. It affects the skin and nerves, especially of the extremities.
++
++
Diagnosis is one or more of:
++
Skin lesions—usually anaesthetic; hypopigmented or reddish maculopapules or annular lesions (see FIG. 15.3)
Thickened peripheral nerves with loss of sensation, e.g. ulnar (elbow), median (wrist), common peroneal (knee) and greater auricular (neck); also peripheral neuropathy or motor nerve impairment
-
Demonstration of acid-fast bacilli in a skin smear or on biopsy
It can be localised (tuberculoid) or generalised (lepromatous)
++
++
++
Referral to specialists or a specialist centre is advisable for shared care.
WHO treatment recommendations are multiple drug therapy, e.g. rifampicin, clofazimine and dapsone, but therapy is constantly being evaluated (see www.who.int/lep).
++
Scrub typhus is found in South-East Asia, northern Australia and the western Pacific. It is caused by Rickettsia tsutsugamushi, which is transmitted by mites.
++
Abrupt onset febrile illness with headache and myalgia
A black eschar at the site of the bite with regional and generalised lymphadenopathy
Short-lived macular rash
Can develop severe complications (e.g. pneumonitis, encephalitis)
++
++
+++
Queensland tick typhus
++
Queensland tick typhus, which is caused by Rickettsia australis, is directly related to a tick bite. The symptoms are almost identical to scrub typhus, although less severe, and the treatment is identical.