Travel Related Infections Flashcards
What is the most important part of history taking with travel related infections?
The calendar time and relative time as well as recent travel history rather than current travel history are the most important parts of the history taking.
What are more common with travel related infections?
With travel related infections certain bacterium such as rickettsia/spirochaete, protozoa and helminths are more common.
What are the key parts to a travel history
- Unwell travel companions or contacts
- Pre travel vaccinations and preventative measures undertaken.
- Recreational activities
- Healthcare exposure
What causes malaria?
It is casued by a parasitic protozoa. There are 4 main species of plasmodium: Falciparum (most common), vivax, ovale and Malariae. The vector for it is the female Anopheles mosquito. It is not contagous from human to human.
What is the normal incubation period for malarial parasites?
Incubation period – minimum 6 days. P Falciparum up to 6-12 days and P.Vivax/Ovale can be up to 1 year+.
How does Malaria present?
Usually presents with fever, chills and sweats may or may not have splenomegaly.
What is severe falciparum malaria?
Severe Falciparum Malaria is when the parasites count is above 2%. This may present with tachycardia, hypotension, arrhythmias, confusion, fits, ARDS (adult respiratory distress syndrome, diarrhoea, deragned LFT, bilirubin, acute kidney injury, low WCC, thrombocytopenia, DIC (deceminated intravascular coagulopathy, anaemia, metabolic acidosis, hypoglycaemia and secondary infection.
What is the general life cycle of the malaria parasite
7 stages to it taking place withint the mosquito and the human. In the Mosquito these take place in both the salivary gland and gut, in humans it take splace in the liver and the blood.
How is malaria managed?
Malaria should be mamaged by an ID physician, 3 blood smears must be taken before you can exlcude malaria. Must do a FBC, UandEs, LFTs, glucose and coagulation. Head CT if CNS symptoms and a CXR.
How is malaria treated and what must we test for before beginning treatment with one of these?
P.falciparum (malignant) – artesunate, quinine and doxycycline.
P.Vavx, ovale, malariae (benign) – chloroquine and primaquine, hypnozoites (used to get rid of liver stage that can lay dormant for years). Before treatment a G6PD screen, to ensure no G6PD deficiency (can cause haemolysis in the presence of primaquine).
How do we prevent malaria infection?
Asses risk in the area especially for regular or returning travellers.
Bite prevention – repellant, adequate clothing, nets, chemoprophoylaxis befor travel including for regular returning travellers
Chemoprophylaxis – specific to region, start before an continue after return generally 4 weeks.
What is enteric fever and what part of the world is usually host to it?
Typhoid and paratyphoid (Enteric fever)
Mainly asia and african and south america due to poor sanitation. Mechanism of infection is faecal-oral from contaminated food/water source is from cases or carriers as it is a human pathogen only.
Describe the organism that causes enteric fever
Salmonella Typhi and Pratyphi A, B and C cause Typhoid Fever. These are enterobacteriaceae, gram negative rods. Virulence comes from an endotoxin (antigen VI) that allows ivnasion and intracellular growth. Fimbiae adhere to epithelium over ileal lymphoid tissue (peyer’s patches) and gets into the lymph system.
What is the incubation period and the symptoms of enteric fever?
Systemic disease (bacteraemia) incubation 7-14 days, fever, headache, abdominal discomfort, constipation and dry cough. Relative bradycardia. Complciations include intestinal haemorrhage and perforation (10% mortality if left untreated) Paratyphoid is generally milder.
What investigations should be done for enteric fever?
Investigations – moderate anaemia, relative lymphopenia (low lymphocytes). Raise LFTs (transaminase and bilirubin). Culture blood and faeces. Serology (antobiody detection not reliable.
