Travel Related Infection Flashcards
What are the unfamiliar features of imported diseases?
Presenting features Isolation requirements Diagnostic methods Treatment Unexpected complications
Why are travellers vulnerable to infection?
Temptation to take risks e.g. food, water, animals, sex
Different epidemiology of diseases
Incomplete understanding of health hazards
Stress of travel
Refugees
What infections are common worldwide?
Influenza
community acquired pneumonia
Meningococcal disease
STIs
What climate/ environment related health problems are there?
Sunburn Heat exhaustion Fungal infections Bacterial skin infections Cold injury Altitude sickness
What methods are infections controllable by public health measures?
What infections are controllable though these measures?
Sanitation:
- Traveller’s diarrhoea
- Typhoid
- Giardiasis
- Amoebiasis
- Food poisoning
- Chloera
Immunisation:
- Poliomyelitis
- Diptheria
Education:
- HIV
- STDs
What water related infection are there?
Schistosomiasis
Leptospirosis
Liver Flukes
Hookworms
What arthropod borne infections are there?
Malaria, Dengue fever - mosquitos
Rickettsial infections - ticks
Leishmaniasis - sand flies
What emerging infectious diseases are there?
Zika virus Ebola virus Swine Flu Avian flu West Nile virus
What important tropical diseases are there?
- Malaria
- Typhoid
- Dengue Fever
- Schistosomiasis
- Rickettsiosis
- Viral Haemorrhagic fevers
- Zika fever
What is the vector for malaria?
Female Anopheles mosquito
What is the parasite called causing malaria?
Plasmodium falciparum - can potentially be severe
The benign forms of the parasite include: • Plasmodium vivax • Plasmodium ovale • Plasmodium malariae • Plasmodium knowlesi
What are the symptoms of malaria?
Fever
Rigors
Aching
Malaise
(abdominal pain, headache dysuria, frequency, sore throat, cough, non-specific)
What are the signs of malaria?
Can be none
Splenomegaly, hepatomegaly, mild jaundice
What are the complications of malaria?
Cerebral malaria (encephalopathy) Blackwater fever (dark urine, renal failure) Pulmonary oedema Jaundice Severe anaemia
How is malaria diagnosed?
Thick + thin blood films
Rapid antigen tests
How is the severity of malaria assessed?
Complicated malaria indicated by one or more of: •Impaired consciousness or seizures •Hypoglycaemia •Parasite count >2% •Haemoglobin < 8mg/dL •Spontaneous bleeding •Haemoglobinuria •Renal impairment or pH < 7.3 •Pulmonary oedema or ARDS •Shock (algid malaria): gram negative bacteraemia
What is the prophylaxis for malaria?
Who needs to take prophylaxis?
Malarone, Mefloquine, Doxcycline
All travellers going to an endemic area including children and pregnant women need to take prophylaxis
What are the treatment options for uncomplicated Plasmodium falciparum?
Riamet - 3 days
or Malarone - 3 days
or Quinine - 7 days (plus doxycycline)
What are the treatment options for complicated Plasmodium falciparum?
IV quinine plus oral doxycycline
What are the treatment options for P. vivax, P. ovale, P. malariae, P. knowlesi?
Chloroquine - 3 days
Riamet - 3 days
NoteL add primaquine (14 days) in P. vivax and P. ovale
What adjuvant measures are there for malaria?
Ventilation (if pulmonary oedema) Maintain glucose level Correct anaemia (blood transfusion) Dialysis if renal failure Exchange transfusion if high parasitaemia
What malaria control programmes are there?
Drainage of stagnant water to prevent mosquito breeding sites
Larvacides against larval life stage
Mosquito killing sprays - DDT
Bed nets, mesh windows
What is the bacterium causing typhoid fever?
Salmonella typhi
Salmonella paratyphi
What are the risk factors for typhoid fevers?
Poor sanitation, unclean drinking water
What are the symptoms of typhoid fever at each stage?
Incubation period of 7 days 4 weeks
1st week: Fever, headache, abdo discomfort, constipation, neutrophilia, confusion
2nd week: fever peaks, diarrhoea begins
3rd week (complications): intestinal bleeding, perforation
4th week: recovery
10-15% relapse
How is typhoid fever diagnose?
Culture blood, urine + stool
Culture bone marrow
What is the treatment for typhoid fever?
Oral azithromycin
IV ceftriaxone if complicated
Note: increasing ciprofloxacin resistance
What is the vector for Dengue fever?
Aedes aegypti (yellow fever mosquito)
What are the clinical features for Dengue fever?
Sudden fever Headache Severe myalgia, arthralgia Rash Haemorrhagic signs
What is the diagnosis for Dengue fever?
Thrombocytopenia
Leucopenia
Elevated transaminases
PCR, serology
What is the management for Dengue fever?
Conservative measures: IV fluids, frozen plasma, platelets
What are the complications of Dengue fever?
Dengue haemorrhage fever
Dengue shock syndrome
What is schistosomiasis caused by?
A parasitic worm that lives in freshwater, the larvae grow inside freshwater snails
What are the clinical features and progression of schistosomiasis?
Swimmers itch
Invasive stage - cough, abdo discomfort, splenomegaly
Katayma fever - fever, diarrhoea, eosinophilia
Acute disease- eggs deposited in bowel (dysentery) or bladder
Chronic disease
How is schistosomiasis diagnosed?
clinical
antibody tests
ova in stools and urine
What is the treatment for schistosomiasis?
Praziquantel
Prednisolone if severe
What is the vector for Rickettsiosis?
What is the bacteria responsible for it?
Ticks
•Tick typhus (R. conorii, R. africae)
- 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 fever, rash, headache, confusion, bleeding
What is the diagnosis for Rickettsiosis?
What is the management?
Dx= Clinical features, serology
Tx= Tetracycline, doxycycline
What are examples of viral haemorrhagic fevers?
Ebola
Congo-Crimea haemorrhage fever
Lassa fever
Marburg disease
max incubation = 3 weeks
What is the course to follow for viral haemorrhage fevers?
Rule out severe infections
Isolation
Supportive treatment
How is Zika virus transmitted?
- Transmitted by daytime-biting Aedes mosquitos
- Also transmitted by sexual contact, blood transfusion
What are the symptoms of Zika virus?
What are the complications?
No or mild symptoms - headache, rash, fever, malaise, joint pains
In pregnancy, can cause microcephaly and other neurological symptoms
Can cause Guillain Barre syndrome
Note, Prevention: mosquito control measures
What is the approach to a fever in returning traveller?
Travel history Precautions taken Risks Symptoms Incubation periods
What investigations can be done if traveller illness suspected?
- FBC
- malaria films
- liver function tests
- stool microscopy & culture
- urine analysis & culture
- blood culture(s)
- CXR
What is the measures if travellers illness suspected?
Isolation + personal protective equipment
Supportive measures
Empirical Tx- Antimicrobial
Specific Tx once diagnosed
Look at the following signs on examination and the indicated disease
(rash, jaundice, lymph nodes, liver, spleen)
- rash - typhoid, typhus, dengue
- jaundice - hepatitis, malaria, Yellow fever
- lymph nodes - leishmania, trypanosomiasis
- liver - malaria, typhoid, amoebic abscess
- spleen – visceral leishmaniasis, typhoid, malaria
