Travel related infection Flashcards
Why are travel infections more prevalent?
Exotic destinations More comorbidities War/natural disasters Migration Emerging infections Accidents abroad
Important factors to consider
Calendar time (certain infections prevalent at certain times of the year) Relative time (incubation period can allow some to be ruled out) Place (important infections)
Bacterium associated with travel
Rickettsia
Spirochaete
Parasites associated with travel
Protozoa (Malaria)
Helminths (worm)
Why is travel history important?
Different strains - present differently Antibiotic resistance (less strict policies) Prevent infection (to ward and lab workers)
Key places where encounter pathogens abroad
Sub-saharan Africa
SE Asia
S/C America
Acute incubation/onset
<10 days
Subacute onset
10-21 days
Chronic onset
> 21 days
What is eosinophilia a sign of?
Allergy
Parasite infection
Different signs/symptoms of travel illness
Resp: SOB/Cough GI: Diarrhoea Skin: Rash Jaundice (Liver/RBC breakdown?) CNS: headache/meningism Haematological (spleno/hepatomegaly/lymphadenopathy) Eosinophilia
Ways of acquiring travel infections
Food/water Insect bite/tick swimming sexual Animal contact Recreational activates (eg caving = fungal risk)
Rodents = risk for
Leptospirosis
Tick bite = risk for
Rickettsia (AND game parks)
Dead slaughtered = risk for
Anthrax
Ebola
Farm = risk for
Q-Fever
Fresh water = risk for
Schistosomiasis
Leptospirosis
Caves = risk for
Histoplasmosis
Unpasteurised dairy
Brucellosis
Malaria patient presentation
High temp Low BP Tachycardia Low O2 sats Confusion Icterus (jaundice of eyes) Bite marks Hepatosplenomegaly
FCB malaria
Anaemic
WCC low
Platelets low
Biochem malaria
Urea high creatinine high bilirubin high Liver ALT and ALP = normal CRP high
ADDITIONAL test malaria
BLOOD FILMS = show presence of parasite
headphones
5 main species of malaria
Plasmodium: falciparum vivax ovale malariae knowlesii
Vector malaria
Female Anopheles Mosquito
Malaria incubation
Minimum 6 days
Falciparum: 4 weeks
Vivax/ovale: 1 year+
History malaria
fever, chills and sweats (3rd/4th day)
Examination malaria
Few signs
Bites/splenomegaly
Cardiovascular severe malaria
Tachycardia
Hypotension
Arrhythmias
Respiratory severe malaria
ARDS
GI severe malaria
Diarrhoea LFT's deranged Bilirubin high (haemolysis)
Renal severe malaria
Acute kidney injury
CNS severe malaria
Confusion/fits
Blood severe malaria
Low/normal WBC
Thrombocytopenia
DIC
Metabolic severe malaria
Metabolic acidosis
Hypoglycaemia
Life cycle malaria
Mosquito gut–> salivary gland and bites human
Salivary gland of mosquito –> liver of human = sporozoite (exoerythrocytic)
Liver schizont then merozoites –> blood (erythocytic and haemolysis)
Back to mosquito via gametocytes
Malaria investigations/tests
3x blood film FBC U&E LFT Glucose Coagulation
CT scan (cerebral oedema?) Chest X ray (pulmonary oedema?)
Treatment P.falciparum
Artesunate
OR Quinine + doxycycline
Treatment P. vivax, ovale, malariae
Chloroquine Additional primaquine (for dormant hypnozoites in liver)
dormant can cause recurrent malaria
Prevention of malaria
Know high risk area Bite prevention (repellent, clothing, bed nets) Chemoprophylaxis (continue after returning)
Typhoid/paratyphoid (enteric fever) presentation
slightly anaemic
low WCC
high CRP
abdominal discomfort
Blood culture typhoid/paratyphoid
Gram -ve bacilli
Salmonella typhi/paratyphi
(paratyphi A, B or C type)
Virulance factors salmonella typhi/paratyphi
Low infectious dose
Survives gastric acid
Fimbriae adhere to epithelial over lymphoid tissue (peyers patches)
Reside within macrophages
Signs and symptoms enteric fever
Systemic disease (sepsis/bacteraemia)
Incubation period: 7-14 days
fever, headache, abdominal discomfort, dry cough
BRADYCARDIA
Complications enteric fever
Intestinal haemorrhage/perforation
10% mortality
Chronic carrier
Which is milder paratyphoid/typhoid?
PARA
Enteric fever investigation results
Moderate anaemia
Lymphopaenia
Mild raised LFT’s
Blood culture and faeces/bone marrow
Treatment enteric fever
Multi drug resistant (to penicillin) Fluoroquinalones Ciprofloxacin (maybe but some resistant)
IV Ceftriaxone (cephalosporin) Azithromycin (macrolide)
If enteric is resistant to cetriaxone?
Meropenem
Prevention enteric fever
Food and water hygiene precautions
Typhoid vaccine
Non typhoidal salmonella symptoms
Food poisoning
diarrhoea, vomiting, abdo pain
Non typhoidal salmonella eg
S typhimurium
S enteritidis
Fever and rash causes
Childhood viruses (measles, rubella, parvovirus) Infectious mononucleosis (EBV/CMV) Acute HIV Rickettsia (spotted fever) Dengue fever
Investigations / signs dengue fever
severe myalgia
headache
Dengue PCR +ve
Rash
What virus is dengue? Where is it found?
Arbovirus - aedes mosquito
Tropical/subtropical regions
Range of infections dengue
4 serotypes
1st infection = asymptomatic/simple rash (classic dengue) only need supportive treatment
REinfection with new serotype = haemorrhagic/shock syndrome
What is reinfection dependent on?
Antibody dependent enhancement (need to have had dengue before)
What is Myiasis?
Fly larvae inside skin (tumbu/bot fly)
hang washing out, fly lays eggs, wear clothes and eggs burrow into skin and hatch
Emerging diseases
Influenza pandemics
SARS Cov
MERS
SARS Cov 2
Ebola
Viral haemorrhagic fever
Filovirus
50% mortality rate
Symptoms ebola
Flu like Vomiting Confusion Diarrhoea Rash Internal/external bleeding
Ebola spread
Direct contact with bodily fluids
Zika virus type and risk
Arbovirus (like dengue is)
Aedes mosquito and Sexual transmission
Congenital microcephaly, foetal loss
Malaria order of cells
Sporozoite in liver
Matures into schizont
Then merozoites
Mosquito reinfected via gametocytes
