Imported infections
Basic features of imported diseases
- cosmopolitan infections
- infections blocked to tropics and subtropics areas
Danger:
diagnosis delay – malaria, typhoid fever, amebosis
risk of spreading – viral hepatitis, typhoid fever, cholera, haemorhagic fevers
Diseases obligatory reported to WHO:
yellow fever, spotted fevers, plague, cholera, haemorhagic fevers, influenza – epidemic
occurence, SARS
Examination in patient with suspected imported disease:
a) detailed personal, work and epidemiologic history:
travel history – vaccination, chemoprophylaxis of malaria
possibility of infection – place of staying, eating of raw food, drinking of defective
water, insects biting, swimming in a river or lake, contact or injury by animal, sexual
contacts with natives
determination of incubation period: short to 10 days, middle: 10-21 days, long: more
than 21 days
b) physical examination
c) look for common causes (pneumonia, infection of urinary tract), establish the principal
sign (fever,diarrhea, jaudice, exanhema, respiratory sign…)
d) above all we must distinguish diseases requireing timely therapy (tropical malaria,
purulent meningitis, typhoid fever, extraintestinal amebiasis, rickttsiosis) and timely
isolation (viral hepatitis, typhoid fever, haemorrhagic fevers)
1. Fever
Malaria
protozoal infection caused by four species of the genus Plasmodium, transmitted by the bite
of an infected female Anopheles mosquito
Plasmodium falciparum (life cycle 24 hours)– malaria tropica
Plasmodium vivax, Plasmodium ovale (l.c. 48 hours)– malaria tertiana
Plasmodium malariae (l.c. 72 hours)– malaria quartana
spread between 45 degree of north and 40 degree of south latitude
annually 400 million new cases – 1,5 to 3 million death
annually imported 10 000 cases to nonendemic countries
Malaria areas
A – Pl. chlorochine sensitive
B – chlorochine resistant Pl. falciparum, rarely Pl. vivax
C – chlorochine resistance widespread
Risk for travelers depends on:
- the area: the degree of endemicity, the predominant Plasmodium species, distribution of
resistance
- season
- type of area visited (urban or rural)
- type of accomodation (air-conditioned or screened indoor versus outdoor)
- duration of exposure
- preventive measures taken
- individual behavior
Incubation period: 7-30 days – months, years
Clinical picture
- fever
- headache
- myalgias
- vomiting
- diarrhea
- cough
Diagnosis
history (prophylaxis) + clinical picture
thin + thick blood films, percentage of parasited red cells
Therapy
malaric attac: chlorochine
quinine
meflochin
atovaquon+proguanil
artemisin
halofantrin
+ doxycyklin, klindamycin
antirelapsing theraty in malaria tertiana:
primaquine
Prophylaxis of malaria
1. exposure prophylaxis: avoid mosquito bites – repelents, mosquito nets
2. chemoprophylaxis: chlorochine, meflochine, atovaquone/proguanil, + doxycyklin,
azithromycin
Stand-by emergency treatment
Schistosomiasis (Bilharsiasis)
200 million infected persons
endemic in Africa, Asia, South America, certain Carribean islands
differention in infectivity and geografical location
S. haematobium, S. japonicum, S. mansoni, S. intercalatum, S. mekongi, S. bovis, number of
avian schistosomes
Transamission: ova in urine and faeces – water – snail - water – skin the host
Clinical picture:
1. cercarial dermatitis („swimmer´s itch“)
2. after 2-9 weeks after exposure: acute schistosomiasis (Katayama fever) – fever,
headache, abdominal pain, hepatosplenomegaly, eosinopholia
3. chronic schistosomiasis – deposition of eggs in tissue and local granuloma formation
Diagnosis
- clinical picture
- identification of parasite eggs in faecal samples or biopsy material
- serology
Therapy
prazikvantel
Dengue fever
causative agent: RNA virus of the Flaviviridae family – four serotypes
transmission by the bite of mosquito Aedes aegypti
spread: between 30 degree north and 20 degree south latitude
Incubation period 3-14 days
Clinical picture
- „breakbone fever“ – muscle aches, back pain, frontal or retroorbital headache, pharyngitis,
arthralgia, rhinitis, cough, exanthema
- dengue haemorhagic fever (DHF)
- dengue shock syndrom
Diagnosis
clinical picture
serology
Therapy
symptomatic
Rickettsial infections
transmitted to humans by various insect vectors: ticks, mites, lice, fleas or by aerosol from
animals and animal products
-
Rickettsia – spotted fever, typhus group, scrub typhus group
Coxiella
Ehrlichia
many imported cases remain undiagnosed – serologic surveys
Dg: serology
Therapy: doxycyklin, clarithromycin, chloramphenicol
Haemorrhagic fevers
Flaviviruses – yellow fever, dengue 1,2,3,4, TBE (Omsk, Kyasanur)
Phlebovirus – Rift valley fever
Nairovirus – Congo - Crimean fever
Hantaviruses – Hantaan, Seoul, Dobrava, Puumala, Sin nombre
Arenaviruses – Junin, Machupo, Guanarito, Sabia, Lassa
Filoviruses – Marburg, Ebola
Fever + remote residence in tropical area
- reactivation of latent infection: TBC, histoplasmosis, melioidosis, leishmanasis
- recrudescence (low- grade persistent infection may expand): malaria, Brill – Zinsser disease
- alteration of immune system by disease or drugs: dissemination of Strongyloides larvae
outside of GIT
- scarring changes of organs: schistosomiasis
- seizures: cysticercosis
- hepatobiliary obstruction: echinococcosis, acute allergic symptoms in rupture of
echinococcal cyst
- hepatocellular malignancy: viral hepatitis B, C
Processes other than infection causing fever after travel
- drugs: taken for prophylaxis, empirical therapy, prescribed for documented infection
- prolonged travel – edema of lower extremity – predisposition to acute streptococcal cellulitis
- prolonged long flights – pulmonary emboli (the economy class sydrom)
Examination of patient with fever
always exclude malaria – repeated microscopy
blood examination:
- BC+dif., FW, CRP
- liver tests, urea,kreatinin
- blood culture
urine examination
serologic tests
sternal puncture
haemocoagulations
2.Diarrhea
- acuta:
cholera – like form : cholera
ETEC
Shigella rare
dysenteria- like form: shigella
Campylobacter
Salmonella
Entamoeba histolytica
EIEC
Yersinia enterocolitica
- subacuta et recurrens
lambliasis
chronic bowel amoebiasis
strongyloidosis
bowel schistosomiasis
3. Jaundice
viral ethiology: viral hepatitis
yellow fever
bacterial ethiology: leptospira infection
Q-fever
parasitic ethiology: amoebic liver absces
fasciolosis
liver schistosomiasis
4. Exanthematic diseases
-
morbilli, rubella, scarlatina, varicella
dengue fever
rickettsioses
syphyllis
Recommendation for travelers
1. Card with data:
blood-group, drugs, allergy, chronic diseases
2. Check before the trip:
validity of vaccination against tetanus, VHA,VHB,typhoid, meningococcus, TBC, diphteria,
polio, yellow fever
3. Malaria
chemoprophylaxis: drugs regularly, record
take with food, enough water
start 1-2 weeks before visiting risk area, end 4 weeks after return
other ways of protection
4. Dietary arrangement
drinking enough safe water, food cooked, boiled, roasted, peeled
5. Sex with unknow partner
proper protection
6. Sun-bath
never between 11 a.m. and 15 p.m., UV filter sun glasses, head protection