++
-
The main diseases facing the international traveller are traveller's diarrhoea (relatively mild) and malaria, esp. CRFM.
-
Infections transmitted by mosquitoes include malaria, yellow fever, Rift Valley fever, Japanese encephalitis and dengue fever. Preventing their bites is excellent prevention.
-
STIs, inc. HIV, of concern in certain areas.
Prevention of disease is a key role for the GP (Table T6)
++
++
++
++
++
++
Treatment of breakthrough malaria during travel (where medical care unavailable):
++
-
Mefloquine 500 mg (2 tabs) statim; repeat after 6–8 h or artemether/lumefantrine (Riamet) 4 tabs at 0, 8, 24, 36, 48, 60 h
+
++
Summary of recommendations
-
CSFM area: chloroquine 300 mg/wk
-
CRFM area: mefloquine 250 mg/wk or doxycycline 100 mg/d
-
Multi-drug resistant area: doxycycline 100 mg/d
For stays >8 wks in areas 2 & 3: chloroquine 300 mg/wk plus doxycycline 50–100 mg/d
Standby treatment: artemether/lumefantrine or Malarone
CSFM = chloroquine-sensitive falciparum malaria
CRFM = chloroquine-resistant falciparum malaria»
++
+++
Fever in the returned traveller
++
Probability diagnosis: malaria, respiratory tract infection inc. bacterial pneumonia, gastroenteritis, dengue fever, Hepatitis A.
++
Serious disorders: as above, TB, typhoid, encephalitis, meningococcal meningitis, meloidosis, amoebiasis (liver abscess), all haemorrhagic fevers, schistosomiasis, African trypanosomiasis.
++
Investigations (if no obvious cause): FBE (?eosinophils), ESR/CRP, thick and thin blood films, blood culture, LFTs, urine-M & C, stool-M & C, new malaria tests, CXR.
+++
Traveller's diarrhoea
++
The illness is usually mild and lasts only 2–3 d. Unusual to last longer than 5 d. Mainly caused by an E. coli strain.
++
++
+++
Severe diarrhoea (patient toxic and febrile)
++
+++
Persistent diarrhoea >2–3 wks
++
++
Also consider Campylobacter jejuni, Salmonella, Yersinia, Cryptosporidium, strongloides, schistosomiasis.
+++
Preventive advice (countries at risk)
++
-
Purify all potentially contaminated water by boiling for 10 mins. 2% tincture of iodine is useful.
-
Do not use ice or salads.
-
Drink hot drinks or reputable bottled soft drinks.
++
Incubation period 10–14 d.
++
Features: ‘step ladder’ fever, abdominal pain, headache (classic), ‘pea soup’ diarrhoea, relative bradycardia
++
DxT: ‘stepladder’ fever + abdominal pain + bradycardia → typhoid (early)
++
Diagnosis: on suspicion → blood culture
++
Treatment: ciprofloxacin 500 mg (o) bd for 7–10 d or azithromycin
++
Incubation period few hours–5 days. Usually mild, uncomplicated episode diarrhoea. Fulminant lethal form with severe water and electrolyte depletion, intense thirst, oliguria.
++
DxT: fever + vomiting + abrupt onset ‘rice water’ diarrhoea → cholera
++
Diagnosis: stool M & C (Vibrio cholera)
++
Treatment: hospitalisation for IV fluids and electrolytes, azithromycin or ciprofloxacin
++
Consider it in sick traveller from endemic area with severe diarrhoea with blood and mucus.
++
Diagnosis: stool microscopy, faecal antigen
++
Treatment: metronidazole 600 mg (o) tds for 7–10 d
++
Often asymptomatic; symptoms include abdominal cramps, bloating, flatulence and bubbly, foul smelling diarrhoea.
++
Diagnosis: 3 specimens faeces-microscopy; ELISA/PCR
++
Treatment: metronidazole or tinidazole, scrupulous hygiene
+++
Specific acquired tropical infections
+++
Dengue (‘breakbone’) fever and chikungunya
++
Similar viral mosquito-borne infections.
++
Febrile illness with severe aching of muscles (myalgia +++) and joints. Possible characteristic erythematous rash with ‘islands of sparing’.
++
DxT: fever + severe myalgia/arthritis + rash → dengue
++
Diagnosis: clinical suspicion → specific antibodies
++
Treatment: is symptomatic with supportive follow-up. Push fluids & simple analgesics. Depression a worry.
++
Caused by a Gram-negative bacillus. It may manifest as a focal infection or as septicaemia with abscesses in the lung, kidney, liver or spleen. It presents with fever, cough and myalgia.
++
DxT: fever + pneumonia + myalgia → melioidosis
++
Diagnosis: blood culture, swabs from focal lesions, haemagglutination test
++
Treatment: ceftazidime 2 g IV 6–8 hrly or meropenem or imipenem (all 14 d) then oral cotrimoxazole ± doxycycline bd + folic acid for 3 mths
++
-
Incubation period: P. falciparum 7–14 d; others 12–40 d
-
Most present within 2 mths of return from tropics
-
Can present up to 2 or more yrs
++
-
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 within 4 d.
-
Typical relapsing pattern often absent.
-
Thick smear allows detection of parasites.
-
Thin smear helps diagnose malaria type.
++
If index of suspicion high, repeat the smear (‘no evidence of malaria’ = 3 negative daily thick films). Monocytosis is a helpful diagnostic clue. Cerebral malaria and blackwater fever are severe and dramatic. Special new tests (e.g. PCR, ICT cards) now available.
++
-
Admit to hospital with infectious disease expertise
-
Supportive measures inc. IV fluids
-
P. vivax, P. ovale, P. malariae (depending on country of source):
-
P. falciparum:
-
artemether/lumefantrine or
-
uncomplicated: quinine (o) + doxycycline or clindamycin or
-
atovaquone/proguanil (Malarone)
-
Severe and complicated: quinine IV then quinine (o) or artesunate IV then Riamet (o)
++
Note: Check for hypoglycaemia. Beware if antimalarial use in previous 48 h.
++
+++
Japanese B encephalitis and meningococcal meningitis
++
Consider these serious infections in a patient presenting with headache, fever and malaise before neurological symptoms such as delirium, convulsions and coma develop. Admit to hospital ASAP for supportive treatment.
+++
Schistosomiasis (bilharzia)
++
-
First sign is local skin reaction (‘swimmer's itch’)
-
Generalised allergic reaction (fever, malaise, urticaria) some days later
-
Other symptoms (e.g. nausea, vomiting, cough)
++
Diagnosis: specific serology; also eggs in excreta
++
++
Prevention: travellers should be warned against drinking from or swimming and wading in dams, watercourses or irrigation channels esp. in Egypt and Africa
+++
African trypanosomiasis (sleeping sickness)
++
++
++
-
Haemolymphatic stage: lymphadenopathy, hepatosplenomegaly
-
Meningoencephalitic stage: including hypersomnolence
++
Diagnosis: on blood smear or chancre aspirate (trypomastigotes)
++
++
Prevention: avoid bites of the tsetse fly
+++
Plague (‘black death’)
++
Caused by Yersinia pestis—transmitted by fleas
++
++
-
bubonic plague—painful suppurating lymph nodes (buboes)
-
pneumonic plague—flu-like symptoms, sepsis, haemorrhage
-
septicaemic plague
++
Diagnosis: serology and smear/culture buboes; repid dipstick tests
++
Treatment: streptomycin and doxycycline
+++
Rabies (a rhabdovirus infection)
++
At first: malaise, headache, painful or itchy bite, fever, agitation. Then either paralytic ‘dumb rabies’ or encephalitic ‘furious rabies’ including hydrophobia (fear of drinking water because of painful pharyngeal muscle spasm)
++
DxT: painful/itchy bite + agitation + hydrophobia → rabies
++
Diagnosis: viral testing PCT (saliva or CSF)
++
Treatment: rabies immunoglobin (within 48 h); rabies vaccine (if unimmunised)
+++
Hansen's disease (leprosy)
++
Diagnosis is one or more of (WHO):
++
-
skin lesions—anaesthetic, hypopigmented or reddish maculopapules or annular lesions
-
thickened peripheral nerves → neuropathy
-
demonstration of acid-fast bacilli in skin smear or on biopsy
++
It can be localised (tuberculoid) or generalised (lepromatous).
++
Diagnosis: biopsy, lepromin test, PCR, skin smear
++
Treatment: multiple drugs (see www.who.int/lep)
++
++
Diagnosis: serology and tissue biopsy
++
Treatment: complex—seek advice
++
Consider infestation of body tissues by larvae (maggots) of flies if traveller presents with ‘itchy boils’ (e.g. tumbu fly, botfly, New World screw worm).
++
Treatment: Vaseline over lump, pressure and tweezer extraction of maggot
+++
Helminth (worm) infections
++
These are classified as nematodes (roundworms), cestodes (tapeworms) and trematodes (flukes). The roundworms which include pinworm (Enterobius vermicularis), whipworm (Trichuris trichiura), human roundworm (Ascaris lumbricoides), human threadworm (Strongyloides stercoralis), hookworm (Ankylostomiasis), filiariasis and larva migrans are the most prevalent worldwide.
+++
Pinworms (also called threadworms)
++
-
Enterobius vermicularis is the most ubiquitous parasitic worm
-
Causes pruritus ani
-
Inspect anus in child about 1 h after sleeping
-
Collect eggs with adhesive tape on perianal skin
++
-
Scrupulous hygiene; shower each morning; cut fingernails short
-
Wash nightwear, underwear and bedlinen in very hot water daily for several days
-
Veterinarian check of household pets
-
Use any one of pyrantel, albendazole, praziquantel or mebendazole as single dose (e.g. pyrantel (o) 10 mg/kg up to 1000 mg). Repeat in 2–3 wks: patient and household contacts.
++
-
Basically light infections that rarely cause problems, usually observed in stool
-
Diagnosis: finding eggs in the faeces
-
Treat with pyrantel or albendazole as single dose
++
About 1–2 cm long these worms can cause failure to thrive, anaemia, abdominal pain, diarrhoea and rectal prolapse with heavy infestation.
++
Diagnosis: microscopy of stool
++
Treatment: single large dose of mebendazole or aldendazole or 3 d course
+++
Human threadworm (strongyloides)
++
These tiny parasites (2 mm or so) are common worldwide. Features if symptomatic are recurrent (low grade) abdominal pain, diarrhoea, ± urticaria and respiratory symptoms. Blood eosinophilia. Can live and reproduce in the body for many years. Aggravated by steroid therapy e.g. septicaemia.
++
DxT: mild abdominal pain + recurrent diarrhoea + blood eosinophilia → strongyloides
++
Diagnosis: larvae in faeces, duodenal biopsy, ELISA test
++
Treatment: ivermectin 200 mcg/kg (o) two doses 2 wks apart (not in children) or albendazole 200 mg bd, 3 d. Antihistamines for pruritus
+++
Cutaneous larva migrans (creeping eruption)
++
A pruritic, erythematous serpiginous eruption on the skin esp. hands, legs and feet. The larvae (of dog or cat hookworms) keep just ahead of the lesion.
++
Diagnosis: clinical appearance; eosinophilia
++
Treatment: usually self-limiting. Can use single dose ivermectin or albendazole
++
-
Lymphatic filariasis—chronic lymphoedema may manifest as a hydrocele, elephantiasis of extremities, genitals, e.g. scrotum, and breasts
Diagnosis: blood film and serology
-
Onchoerciasis (river blindness)—skin disease and chronic eye disease (uveitis and optic atrophy)
Diagnosis: PCR
Treatment of filariasis: ivermectin
-
Loiasis (due to Loa Loa—a filaria)
In Africa: painful swellings of angioedema (Calabars) mainly on limbs, eosinophilia, worms may migrate across eyes (subconjunctivae)
Diagnosis: microscopy of mid-day blood sample
Treatment: diethylcarbamazine 6 mg/kg (o) stat.
++
Parasites from sheep areas can migrate anywhere but usually form cysts on lungs. May be asymptomatic or skin cysts and abdominal discomfort.
++
Diagnosis: serology, ultrasound
++
Treatment: surgical cystectomy, albendazole
+++
Dracunculus medimensis (Guinea worm)
++
Causes local symptoms such as pain and intense itching at skin ulcer or blister as the worm emerges into the skin. The longest nematode.
++
Treatment: slow extraction of pre-emerging worms, metronidazole ± corticosteroids
++
-
First sign—‘creeping eruption’ at entry point on feet
-
1–2 wks later—respiratory symptoms like pneumonia
-
Anaemia follows
-
Iron deficiency (commonest cause in world)
++
Diagnosis: larvae or ova in stool
++
Treatment: single dose mebendazole or pryantel
++
Prevention: use footwear in endemic areas
+++
Viral haemorrhagic fevers (VHF)
++
These infections, which belong to the domain of tropical medicine, include Ebola virus, Lassa fever, yellow fever, dengue, chikungunya and hantavirus. Many have names based on the area where the VHF was first described, esp. South American types, e.g. Junin, Machupo, Sabia.
++
++
Early symptoms: fever, myalgia, headache, abdominal symptoms (ANV, diarrhoea, pain), upper respiratory (cough, sore throat, chest pain), flushed skin or rash. May progress to thrombocytopenia, anaemia, DIC with bleeding including frank haemorrhage, hypotension/shock and multiorgan failure.
++
Transmission: direct body contact (body fluids from affected person or dead person); contaminated objects (needles, medical equipment) and infected animals.
++
Diagnosis: PCR, histopathology
++
Treatment: supportive care, strict isolation and quarantine measures; the future—antivirals, synthetic antibodies
++
Milder cases present with flu-like symptoms, relative bradycardia (Faget's sign) and albuminuria. Severe cases develop abrupt fever with prostration, jaundice and abnormal bleeding.
++
Diagnosis: viral culture, serology (ELISA)