Travel Related Infections Flashcards
Why are travellers vulnerable to infection?
- tempted to take risks away from home
- different disease epidemiology
- incomplete understanding health hazards
- stress of travel
- refugees; deprivation, malnutrition, disease, injury
What are common worldwide infections?
Influenza, community acquired pneumonia, meningococcal disease, STDs
What are climate/environmental health problems?
Sunburn Heat exhaustion and heatstroke Fungal infections Bacterial skin infections Cold injury Altitude sickness
What traveler infections are controlled through sanitation?
- travelers’ diarrhoea
- typhoid
- hep A or E
- giardiasis
- amoebiasis
- helminth infections
- viral gastroenteritis
- food poisoning
- shigella dysentery
- cholera
- cryptosporidiosis
What traveler infections are controlled through immunisation?
Poliomyelitis
Diphtheria
What are some water related infections?
- schistosomiasis
- leptospirosis
- liver flukes
- strongyloidiasis
- hookworms
- guinea worms
What are some arthropod borne infections?
- malaria, dengue fever
- rickettsial infections
- leishmaniasis
- trypanosomiasis
- filariasis
- onchocerciasis
What arthropod causes malaria and dengue fever?
Mosquitoes
What arthropod causes rickettsial infections?
Ticks; typhus
What arthropod causes leishmaniasis?
sand flies; Kala-azar
What arthropod causes trypanosomiasis?
tsetse fly; sleeping sickness
What arthropod causes onchocerciasis?
black flies; river blindness
Describe the species of malaria
Plasmodium falciparum (potentially severe)
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi
What are the clinical features of malaria?
Non-specific
Fever, rigors, aching bones, abdo pain, headache, dysuria, frequency, sore throat, cough
What are the major complications of malaria?
6 major
- cerebral malaria; hypoglycaemia, convulsions, hypoxia
- blackwater fever; dark urine due to intravascular haemolysis - acute renal failure
- pulmonary oedema
- jaundice
- severe anaemia
- algid malaria
Describe management of malaria
Diagnosis through thick and thin blood films, quantitative buffy coat, rapid antigen tests
Severity assessment; complicated or not
How is malaria assessed for severity?
Complicated malaria is one or more of
- impaired consciousness or seizures
- hypoglycaemia
- parasite count >2%
- haemoglobin <8mg/dL
- spontaneous bleeding / DIC
- haemoglobinuria
- renal impairment or pH <7.3
- pulm oedema or ARDS
- shock (algid malaria)
What are drugs for malaria?
Quinine (from chinchona) and artemisinins (from Quinghaosu)
How is uncomplicated falciparum malaria treatment?
- Riamet 3 days
- Eurartesim 3 days
- Malarone 3 days
- Quinine 7 days + oral doxycycline
How is complicated or severe falciparum malaria treated?
- IV artesunate
- IV quinine + oral doxycycline
- once stable and can swallow switch to oral
How are vivax, ovale, malariae and knowlesi malaria treated?
- Chloroquine 3 days
- Riamet 3 days
- add primaquine in vivax and ovale to eradicate liver hypnozoites
Describe some malaria control programmes
Mosquito breeding site drainage of standing water
Larvacides
Mosquito killing sprays
Human behaviour i.e. ned nets and mesh windows
What are the two typhoid viruses?
Salmonella typhoid and salmonella paratyphi
Describe the clinical features of typhoid
1st week; fever, headache, abdo discomfort, constipation, dry cough, relative bradycardia, neutrophilia, confusion
2nd week; fever peaks at 7-10days, rose spots, diarrhoea begins, tachycardia, neutropenia
3rd week; intestinal bleeding, perforation, peritonism, metastatic infections
Week 4; 10-15% relapse but recover generally
Describe diagnosis of typhoid
Lab culture blood, urine and stool
Culture bone marrow
What is the treatment of typhoid?
Oral azithromycin
IV ceftriaxone (if complicated or concerned regarding absorption)
Describe the clinical features of dengue fever
- Sudden fever
- severe headache
- retro-orbital pain
- severe myalgia
- arthralgia
- macular/maculopapular rash
- haemorrhagic signs; petechiae, purpura, positive tourniquet test
Describe the diagnosis of dengue fever
Thrombocytopaenia, leucopenia, elevated transaminases, positive tourniquet test
Lab; PCR, serology
Describe the management of dengue fever
No specific therapeutic agent
Complications; dengue haemorrhagic fever, dengue shock syndrome
Rx; IV fluids, fresh frozen plasma, platelets
Prevention; avoid bites, new vaccine
What causes schistosomiasis?
S haematobium
S mansoni
S japonicum
Describe schistosomiasis clinically
Swimmer’s itch (first few hours)
After 24hrs; cough, abdo discomfort, splenomegaly, eosinophilia
Katayam fever after 15-20 days
Acute disease 6-8 weeks
Chronic disease
Describe diagnosis of schistosomiasis
Clinical diagnosis
Antibody tests
Ova in stools and urine
Rectal snip
Describe the treatment of schistosomiasis
Praziquantel; 20mg/kg, two doses 6hrs apart
Prednisolone if severe
Describe tick typhus organisms
R conorii
R africae
Causes Rickettsiosis
Describe rickettsiosis
Caused by tick typhus
Abrupt onset swinging fever, headache, confusion, endovasculitis, rash, bleeding
How is tick typhus/rickettsiosis managed?
tetracycline
Describe viral haemorrhagic fevers
Serious but rare in UK
- ebola
- Congo-Crimea haemorrhagic fever
- lassa fever
- marburg disease
Max incubation period 3 weeks
How do you treat viral haemorrhagic fevers?
Isolation; high security infection unit
Treatment; supportive
Describe Zika virus
Flavivirus
No or mild symptoms; headache, rash, fever, joint pains, fever, malaise
Can cause Guillain barre syndrome
No antiviral therapy
mosquito control measures and vaccines in development
What can zika virus cause in pregnancy?
Microcephaly and other neurological problems
How do you approach management of a fever in a returning traveler?
History; tropical, travel, precautions, risks, symptoms, incubation periods
Examination signs; rash, jaundice, lymph nodes, liver, spleen
Investigations; FBc, malaria films, LFTs, stool microscopy and culture, urine analysis and culture, blood culture, CXR
Treatment; isolation? PPE?, supportive measures, empirical treatment if unwell
What is the malaria vector?
female anopheles mosquito
Describe katayama fever
15-20 days after schistosomiasis
- prostrate
- fever
- urticaria
- lymphadenopathy
- splenomegaly
- diarrhoea
- eosinophilia
