Travel Related Infection Flashcards
What factors make travellers more at risk from infection?
Temptation to take risks when away from home (food, water, animals, sex)
Different epidemiology of some diseases
Incomplete understanding of health hazards
Stress of travel
Refugees
What infections are common world wide?
Influenza
Community-acquired pneumonia
Meningococcal disease
Sexually transmitted disease
What are some climate/temperature related health problems?
Sunburn Heat exhaustion and heatstroke Fungal infections Bacterial skin infections Cold injury Altitude sickness
What are some common water-related travel-related infections?
Schistosomiasis Leptospirosis Liver flukes Strongyloidiasis Hookworms Guinea worms
What are the common tropical diseases to be aware of?
Malaria Typhoid Dengue Fever Schistosomiasis Rickettsiosis Viral haemorrhagic fevers (ie ebola) Zika fever
What pathology underlies a malaria infection?
parasites replicating within red blood cells, causing these cells to burst and the disease to spread to other red cells
Where is malaria most common?
In the tropics and subtropics
What is the vector for malaria?
The female anopheles mosquito
What is the non-benign species of malaria?
Plasmodium falciparum
What are the symptoms of malaria?
Fever Rigors Aching bones Abdominal pain Headache Dysuria Frequency Sore throat Cough
What are the signs of malaria?
Often none
Splenomegaly
Hepatomegaly
Mild jaundice
What are the complications of malaria?
Cerebral malaria (potentially fatal, more common in non-immune visitors and children in endemic areas, causes hypoglycaemia, convulsions and hypoxia)
Blackwater fever (causes severe intravascular haemolysis, high parasitaemia, profound anaemia, haemoglobinuria and acute renal failure. Also causes urine to be very dark due to renal system damage) Pulmonary oedema
Jaundice
Severe anaemia
Algid malaria (gram-negative septicaemia)
How is malaria diagnosed?
Thick and thin blood films (gold standard)- Giemsa, Field’s stain (can identify species of malaria)
Quantitative buffy coat- centrifugation, UV microscopy (quicker than blood films)
Rapid antigen tests- OptiMal, ParaSight-F (used when no access to healthcare)
How is malaria graded?
Severe or non-severe Severe if one or more of following present: -Impaired consciousness or seizures -Hypoglycaemia -Parasite count >/=2% -Haemoglobin >/= 8mg/dL -Spontaneous bleeding / DIC -Haemoglobinuria -Renal impairment or pH <7.3 -Pulmonary oedema or ARDS -Shock (algid malaria)- ?Gram negative bacteraemia
What are the treatment options for uncomplicated P falciparum malaria?
Riamet- 3 days (first line)
Eurartesim- 3 days
Malarone- 3 days
Quinine plus oral doxycycline or clindamycin- 7 days
What are the treatment options for complicated P falciparum malaria?
IV quinine (SE- cardiac depression, cerebral irritation, N&V) plus oral doxycycline or clindamycin IV artenusate (unlicensed in UK) When patient is stable and able to swallow, switch to oral treatments
What are the other malarial species other than P. falciparum?
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi
How are the other malarial species other than P. falciparum treated?
Cholorquine- 3 days
Riamet- 3 days
Add primaquine for 14 days in vivax and ovale to eradicate liver hypnozoites
What are some malarial control programmes?
Drainage of standing water to reduce mosquito breeding sites
Larvacides
Mosquito killing sprays (DDT, malathion)
Human behaviour (bed nets, mesh windows)
What is the causative organism of typhoid/enteric fever?
Salmonella typhi
Salmonella paratyphi
What are the clinical features of typhoid fever?
Incubation period of 1-4 weeks
1st week- fever, headache, abdominal discomfort, constipation, dry cough, relative bradycardia, neutrophilia, confusion
2nd week- fever peaks at 7-10 days, Rose spots, diarrhoea, tachycardia, neutropenia
3rd week- intestinal bleeding, perforation, peritonism, metastatic infections
4th week- 10-15% relapse
How is typhoid fever diagnosed?
Laboratory diagnosis through culture of:
- Blood
- Urine
- Stool
- Bone marrow
How is typhoid fever treated?
Oral azithromycin (uncomplicated) IV ceftriaxone (complicated)
What regions have the highest incidence of Dengue fever?
Southeast Asia
Southern America
Parts of Central Africa
How is Dengue fever transmitted?
Via the aedes aegypti mosquito (lives in water)
What are the clinical features of Dengue fever?
Sudden fever Severe headache, retro-orbital pain Severe myalgia and arthralgia Macular/ maculopapular rash Haemorrhagic signs: petechiae, purpura, positive tourniquet test
How can diagnosis of Dengue fever be done?
Clinical: - Thrombocytopenia - Leucopenia - Elevated transaminases - Positive tourniquet test- spots appear on arm when tourniquet applied Laboratory: - PCR - Serology
How is Dengue fever treated?
No specific therapeutic agents
IV fluids, FFP and platelets helpful in preventing complications
What are the complications of Dengue fever?
Dengue haemorrhagic fever
Dengue shock syndrome
What are the microbial causes of schistosomiasis?
S. haematobium
S. mansoni
S. japonicum
Where does schistosomiasis breed?
In freshwater and freshwater snails
Where is schistosomiasis most common?
South America
Africa
Southeast Asia
What are the clinical features of schistosomiasis?
Swimmers Itch (1st few hrs)
-clears 24-48hrs
Invasive stage (after 24hrs)
-cough, abdo discomfort, splenomegaly, eosinophilia
Katayama Fever (after 15-20 days)
-prostate, fever, urticaria, lymphadenopathy, splenomegaly, diarrhoea, eosinophilia
Acute disease (6-8 weeks)
-eggs deposited in bowel (dysentery) or bladder (haematuria)
-Chronic disease
How is schistosomiasis diagnosed?
Clinically
Serology
Presence of ova in stool or urine
Rectal snip (if rapid diagnosis required)
How is schistosomiasis treated?
Two doses of praziquantel six hours apart
Prednisolone required in severe cases
What are the features of tick typhus?
Result of infection from ticks typically in southern africa
Incubation period of one week
Maculopapular rash develops
Diagnosis done clinically
What are the causes of rickettsiosis?
Tick typhus Rocky Mountain Spotted Fever (R. rickettsii) Epidemic typhus (R. prowazekii) Murine or endemic typhus (R. mooseri) Scrub typhus (R. tsutsugamushi)
What are the clinical features of rickettsiosis?
Abrupt onset swinging fever Headache Confusion Endovasculitis Rash (macular, petechial) Bleeding
How is rickettsiosis diagnosed?
Clinically
Serology
How is rickettsiosis treated?
Tetracycline
What are the most common types of viral haemorrhagic fevers?
Ebola
Congo-Crimea haemorrhagic fever
Lassa fever
Marburg disease
What is the incubation period for viral haemorrhagic fevers?
Maximum of three weeks
How is Zika virus transmitted?
Aedes mosquito
Sexual contact
Blood transfusion
What infections can Zika virus be related to?
Dengue fever
Yellow fever
Jap B encephalitis
West nile viruses
What are the clinical features of Zika virus?
Often no or mild symptoms Headache Rash Fever Malaise Conjunctivitis Joint pains In pregnancy- microcephaly and other neurological problems such as Guillain-Barre syndrome
