Travel Infections

Question 1

If a travel infection isn’t treated with antibiotics what kind of differential diagnosis are you thinking?

Answer 1

Parasite - maybe malaria

Question 2

Why is travel history important?

Answer 2

Gives idea of imported diseases
Helps identify treatment
Different strains of pathogen antigenically different
Antibiotic resistance

Question 3

What should you ask in the travel history?

Answer 3

When they went
When they came back
Have they been in contact with anyone unwell
Pre travel vaccinations
Preventative measures
Recreational activities
Healthcare exposure

Question 4

What are symptoms/signs malaria?

Answer 4

Sometimes NONE

Othertimes - Fatigue, fever, malaise, hepatosplenomegaly, fever can be tertian

Question 5

What are the three most common species of malaria?

Answer 5

Plasmodium falciparum
Plasmodium ovale
Plasmodium vivax

Question 6

What is the method of transmission of malaria?

Answer 6

Vector - female mosquito

Question 7

Can you have case to case spread?

Answer 7

No

Question 8

If the person has travelled from Africa what is the most likely plasmodium?

Answer 8

Falciforum

Question 9

If the person has travelled from India what are the two most likely plasmodiums?

Answer 9

Ovale

Vivax

Question 10

What is the incubation period?

Answer 10

Min 6 days
P falciform up to 6/12
P vivax/ovale up to 1 year

Question 11

Why such a long incubation period?

Answer 11

Due to dormant stage in liver

Question 12

On examination what might you see indicating malaria?

Answer 12

Not much apart from increased temp and splenomegaly

Question 13

Which is the most severe malaria? Why? How much burden do you need?

Answer 13

Falciparum - only need 2% burden
Can lead to microvasc occlusion which can lead to cardiac problems, acute respiratory distress syndrome DIC CNS problems, tachy, diarrhoea etc.

Question 14

What is the lifecycle of malaria in an infected human?

Answer 14

Malaria infected mosquito bites 
Releases sporozoites 
Travel to liver and infect liver cells 
Mature into schizonts 
Form merozoites 
Lyse and release into blood stream
Infect RBCs - form more merozoites
and so on...lyse etc
Some meozoites become gametocytes - female mosquito feeding can pick up these gametocytes and become infected

Question 15

What blood tests would you do for malaria? Other tests?

Answer 15

3 x blood films - thick and thin (thick looks at parasites in general - thin looks more closely at malaria parasites)
Rapid antigen test

Blood cultures - to check for bacterial origin
FBCs - platlets/WBC/RBC etc
LFTs - deranged 
Albumin - indication of liver function
Bilirubin- raised in haemolysis due to breakdown of haem
Glucose - gives hypoglycaemia
Clotting if platelets low
CRP - inflammation
U and Es - affects kidneys

Chest Xray

Question 16

What blood results might you see for malaria?

Answer 16

Positive blood film for parasite 
Positive antigen test
Raised bilirubin due to haemolysis
Deranged LFTs due to liver dysfunction
Low/normal WBC
Low platelets
Hypoglycaemic

Question 17

What is the treatment for malaria?

Answer 17

Falciparum - artesunate. quinine + doxycycline

Viviax and ovale - chloroquine and primaquine

Question 18

Which enzyme deficiency disorder are you concerned about in someone with malaria?

Answer 18

G6PDH - as get haemolytic anaemia. Will be even worse with malaria

Question 19

Why can’t you give chloroquine and primaquine to falciparum malaria?

Answer 19

Resistant

Question 20

What is the ABC of malaria prevention?

Answer 20

A - assess risk/knowledge of area
B - bite prevention - clothes, nets, repellant
C - chemoprophylaxis - start before and continue after return

Question 21

What are differentials for malaria?

Answer 21

Typhoid
Dengue
Rickettsial infection
Meningococcal septicaemia

Question 22

If Salmonella typhi is on blood culture what is the diagnosis? Where would you catch this most likely? What from? What is the method of transmission? What is the incubation period? Symptoms?

Answer 22

Typhoid/paratyphoid
Asia
Poor sanitation
Falco-Oral - cases or carriers only - human pathogen
7-10 days
Fever headache abdominal discomfort constipation dry cough
Relative bradycardia

Question 23

What is a major complication of salmonella typhi?

Answer 23

Intestinal haemorrhage and perforation - 10% mortality if untreated

Question 24

What is the difference between typhoid/paratyphoid?

Answer 24

Paratyphoid is generally milder

Question 25

How would you diagnose typhoid?

Answer 25

Culture - blood/faeces
Moderate anaemia
Relative lymphopenia
Raised LFTs (transaminase and bilirubin)

Question 26

How do you treat typhoid?

Answer 26

Ceftriaxone

Question 27

How do you prevent typhoid (2)?

Answer 27

Food and water hygiene precautions
Typhoid vaccine
Live attenuated vaccine - 50-75% effect

Question 28

What are the differentials for fever and rash?

Answer 28

Measles, mumps, rubella, EBV, CMV, acute HIV, dengue

Question 29

How do you test for dengue?

Answer 29

Viral PCR

IgM antibody serology

Question 30

What kind of virus is dengue?

Answer 30

Arbovirus

Question 31

What is the interesting thing about dengue?

Answer 31

2nd time infected with different serotype = antibody dependent enhancement and severe haemorrhagic fever/dengue shock syndrome

Question 32

What are the symptoms of dengue?

Answer 32

Asymptomatic to severe febrile illness
Rash
Fever

Question 33

What virus causes Ebola?

Answer 33

Filovirus

Question 34

What are the symptoms?

Answer 34

Flu like with vomitting, diarrhoea, headaches, confusion, internal/external bleeding at 5-7days.

Question 35

How is it spread?

Answer 35

Direct contact with body fluids

Question 36

How is it treated? Prevented?

Answer 36

Antivirals
Monoclonal antibiotics

Now have vaccine

Question 37

What is Zika virus?

Answer 37

Arbovirus - differential for dengue - flu like

Question 38

What is the important thing to remember about Zika virus? Is there any vaccine or treatment?

Answer 38

Congenital microcephaly - foetal loss
Sexual transmission
No treatment no vaccine