Tropical diseases Flashcards
(46 cards)
What is the most common cause of fever in travellers from Sub-Saharan Africa?
Malaria - 62% of systemic fever cases
What are some of the symptoms of Malaria?
GI toxicity Respiratory problems - cough, breathlessness Headaches FEVER
What are some of the travellers diseases that present with systemic fever?
Malaria Dengue fever Mononucleosis Salmonella typhi - Typhoid Ricketsial infection
What is the most common cause of fever in travellers from the Carribean and South East Asia?
Dengue fever
What is the most common cause of fever in travellers from Asia?
Typhoid
Which diseases are mosquitoes responsible for?
Malaria
Zika virus
Dengue fever
What are the two types of mosquitoes which commonly transmit disease?
Aedes - day-biter
Anopheline - evening biter
Which season means there’s an increase in mosquito numbers?
End of the rainy season - increased amount of stagnant water for mosquitoes to lay eggs in
How can people physically avoid mosquitoes?
Stay indoors - AC, screens Impregnated netting - Permethrin (insecticide) - tucked in before the sun goes down (mosquito free) Clothing - Cover up (arms, legs, ankles, feet) - Spray/soak clothing
Which insect repellent works (Evidence based results)?
DEET
- makes you taste really bad to mosquitoes
What do you have to do to ensure DEET works?
30% DEET
Re-apply every 3-4 hours (more if you go swimming)
Remember to put it on the ankles
What is the worldwide distribution of Malaria?
South America
- Amazon basin
Sub-Saharan Africa
What is the life-cycle of Malaria?
Mosquito bites you
Malarial virus enters the bloodstream
Travels to the liver and sits there, growing (incubation period)
Spill out of liver and into blood where they lyse RBCs
- symptom development
- sticky RBCs (causing clots)
How long is the incubation period of Malaria?
Varies depending on the type of Malaria
- P.falciparum - 7-14 days
- P.malaria - 18-40 days
What are the different types of malaria?
P.falciparum (most deadly kind)
P.vivax
P.ovale
P.malaria
How is malaria diagnosed?
Blood films
Antigen test
PCR
Describe thick and thin blood films in Malaria diagnosis
Thick
- a thick blob of blood is put on a slide and stained with a substance that lyses RBCs
- the parasite can be seen stacked up on the film under a microscope
- helps see if the patient has Malaria at all
Thin
- a thin blob of blood is smeared on a slide
- the parasites can be seen within the RBCs
- easy to miss Malaria due to thin nature of the film
- helps diagnose which type of Malaria the patient has
Describe antigen testing in regards to Malaria diagnosis.
Like a pregnancy test
Comes up with bands depending on which antigens are present
Describe how PCR can be used to diagnose Malaria?
Amplification of the DNA can help diagnose which type of Malaria the patient has
What is the classic presentation of Malaria?
Fever Malaise Headache Myalgia Diarrhoea
What are some possible clinical features of Malaria? (aside from the classical presentation)
Anaemia - lysis of RBCs
Jaundice - lysis of RBCs
Renal impairment
- block microcirculation
What are some of the symptoms of severe malaria?
Parasitaemia (greater than 2% of RBCs infected) Cerebral malaria - blockage of micro-circulation Severe anaemia Renal failure Shock DIC Acidosis Pulmonary oedema
How is malaria treated?
Quinine and Doxycycline - dual therapy because of resistance Artemether compounds - don't have side effects of quinine - better in severe Malaria Prevention is best method of treatment - avoidance - chemoprophylaxis
What are the different types of malarial chemoprophylaxis?
Mefloquine - once weekly with psychiatric side effects
Doxycicline - daily, and can cause photosensitisation
Malarone - minimal side effects, but very effective
