Travel Related Infections Flashcards
1
Q
Why are travellers vulnerable to infection?
A
- Temptation to take risks away from home (food, water, animals, sex)
- Different epidemiology of some diseases (HIV, TB, polio, diphtheria)
- Incomplete understanding of health hazards
- Stress of travel
- Refugees: (deprivation, malnutrition, disease, injury)
2
Q
What infections are common worldwide?
A
- Influenza
- Community acquired pneumonia
- Meningococcal disease
- Sexually transmitted diseases
3
Q
Give examples of climate/environmental relayed health problems.
A
- Sunburn
- Heat exhaustion and heatstroke
- Fungal infections
- Bacterial skin infections
- Cold injury
- Altitude sickness
4
Q
What infections are controllable by public heath measures regarding sanitation??
A
- Travelers’ diarrhoea
- Typhoid
- Hepatitis A or E
- Giardiasis
- Amoebiasis
- Helminth infections
- Viral gastroenteritis
- Food poisoning
- Shigella dysentery
- Cholera
- Cryptosporidiosis
5
Q
What infections are controllable by public heath measures regarding immunisations?
A
- Poliomyelitis
- Diphtheria
6
Q
What infections are controllable by public heath measures regarding education?
A
- HIV
- STDs
7
Q
Give examples of water-related infections
A
- Schistosomiasis
- Leptospirosis
- Liver flukes
- Strongyloidiasis
- Hookworms
- Guinea worms
8
Q
Give examples of arthropod-borne infections.
A
- Malaria (mosquitos)
- Dengue fever (mosquitos)
- Rickettsial infections (ticks: typhus)
- Leishmaniasis (sand flies: Kala-azar)
- Trypanosomiasis (tsetse fly: sleeping sickness)
- Filariasis (mosquitoes: elephantiasis)
- Onchocerciasis (black flies: River Blindness)
9
Q
Give some examples of some emerging infectious diseases worldwide.
A
- Zika: Latin America, Caribbean
- Ebola virus disease: West Africa
- MERS-CoV: Middle East
- Swine ‘flu (H1N1): worldwide
- Avian ‘flu (H5N1 and H7N9): China
- SARS: Far East, worldwide
- West Nile Virus: USA
10
Q
Give examples of some important tropical disease to be aware of.
A
- Malaria
- Typhoid
- Dengue Fever
- Schistosomiasis
- Rickettsiosis
- Viral haemorrhagic fevers
- Zika fever
11
Q
What is the epidemiology of malaria?
A
United Kingdom (HPA, 2015)
- 1400 cases/year
- 6 deaths/year
Worldwide (WHO, 2012)
- 207 million cases/year
- 627,000 deaths/year
12
Q
What is the malaria vector?
A
The female anopheles mosquito
13
Q
Describe the lifecycle of malaria.
A
- Mosquito bites human and injects sporozoites that migrate to the liver
- Sporozoites become merozoites
- Merozoites enter circulation with RBC and mature to male and female gametocytes
- Gametocytes for zygotes which mature to sporozoites
- Sporozoites transferred to mosquito when they bite humans
14
Q
What are the 5 species of malaria?
A
Potentially severe
-Plasmodium falciparum
Benign
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
- Plasmodium knowlesi
15
Q
What symptoms can malaria present with?
A
- Fever
- Rigors
- Aching bones
- Abdominal pain
- Headache
- Dysuria
- Frequency
- Sore throat
- Cough
16
Q
What signs can malaria present with?
A
- None
- Splenomegaly
- Hepatomegaly
- Mild jaundice
17
Q
What are the possible complications of malaria?
A
- Cerebral malaria (encephalopathy)
- Blackwater fever
- Pulmonary oedema
- Jaundice
- Severe anaemia
- Algid malaria
18
Q
How does cerebral malaria present?
A
- Hypoglycaemia
- Convulsions
- Hypoxia
19
Q
How does Blackwater fever present?
A
- Severe intravascular haemolysis
- High parasitaemia
- Profound anaemia
- Haemoglobulinuria
- AKI
20
Q
What is algid malaria?
A
Gram negative septicaemia
21
Q
How is malaria diagnosed?
A
Thick & thin blood films
-Giemsa, Field’s stain
Quantitative buffy coat (QBC)
-Centrifugation, UV microscopy
Rapid antigen tests
- OptiMal
- ParaSight-F
22
Q
How is the severity of malaria assessed?
A
Complicated malaria= 1 or more:
- Impaired consciousness or seizures
- Hypoglycaemia
- Parasite count 2% or higher
- Haemoglobin 8mg/dL or less
- Spontaneous bleeding / DIC
- Haemoglobinuria
- Renal impairment or pH <7.3
- Pulmonary oedema or ARDS
- Shock (algid malaria)
23
Q
What are the treatment options for uncomplicated P, falciparum malaria?
A
- Riamet (3 days)
- Euartesim (3 days)
- Malarone (3 days)
- Quinine (7 days) plus oral doxycycline or clindamycin
24
Q
What are the possible side effects of oral quinine?
A
- Nausea
- Tinnitus
- Deafness
- Rash
- Hypoglycaemia
25
What are the treatment options for complicated or severe P falciparum malaria?
- IV artesunate
| - IV quinine plus oral doxycycline or clindamycin
26
What are the possible side effects of IV quinine?
- Cardiac depression
- Cerebral irritation
- N+V
27
How is malaria caused by organisms other than P falciparum treated?
- Chloroquine (3 days)
- Riamet (3 days)
- Add primaquine (14 days) in vivax and ovale to eradicate liver hypnozoites
28
What programmes are there in place to control malaria?
- Drainage of standing water to prevent mosquito breeding sites
- Larvacides
- Mosquito killing sprays
- Human behaviour including bed nets and mesh windows
29
What organisms cause typhoid (enteric) fever?
- Salmonella typhi
| - Salmonella paratyphi
30
What is the epidemiology of typhoid?
- Global cases: 27 million infections/yr
- Global deaths:over 200,000/yr
- UK cases: 500/yr
31
What conditions make typhoid more likely?
- Poor sanitation
| - Unclean drinking water
32
What is the incubation period for typhoid?
7-28 days
33
What are the clinical features of typhoid within the 1st week?
- Fever
- Headache
- Abdominal discomfort
- Constipation
- Dry cough
- Relative bradycardia
- Neutrophilia
- Confusion
34
What are the clinical features of typhoid in the 2nd week?
- Fever peaks at 7-10 days
- Rose spots
- Diarrhoea begins
- Tachycardia
- Neutropenia
35
What are the clinical features of typhoid in the 3rd week?
- Intestinal bleeding
- Perforation
- Peritonism
- Metastatic infections
36
What are the clinical features of typhoid in week 4?
- Usually recovery
| - 10-15% relapse
37
How is typhoid fever diagnosed?
- Clinically not easy due to evolution of features
- Culture of blood, urine and stool
- Culture of bone marrow
38
What is the treatment for typhoid fever?
- Oral azithromycin
| - IV ceftriaxone
39
What is the commonest human arbovirus infection?
Dengue
40
What is the epidemiology of Dengue fever?
- Dengue infection: 100 million cases/year
| - Dengue Deaths: 25,000/year
41
What is the vector in dengue?
Aedes aegypti (mosquito)
42
What is the classical presentation of dengue?
- Sudden fever
- Severe headache, retro-orbital pain
- Severe myalgia and arthralgia
- Macular/ maculopapular rash
- Haemorrhagic signs: petechiae, purpura, positive tourniquet test
43
How is dengue diagnosed?
Clinically
- Thrombocytopenia
- Leucopenia
- Elevated transaminases
- Positive tourniquet test
Laboratory
- PCR
- Serology
44
How is dengue managed?
No specific therapeutic agents
45
What are the possible complications of dengue?
- Dengue haemorrhagic fever (DHF)
| - Dengue shock syndrome (DSS)
46
How are the complications associated with dengue managed?
- IV fluids
- Fresh frozen plasma
- Platelets
47
How is dengue prevented?
- Avoid bites
| - New vaccine but limited use
48
What vectors are involved in schistosomiasis?
- S. haematobium
- S. mansoni
- S. japonicum
49
How is schistosomiasis transmitted?
Freshwater snails
50
Describe the lifecycle of schistosomiasis.
- Vectors excreted by infected human in faeces and urine enter freshwater
- Eggs hatch releasing miracidia which penetrate the snails tissues.
- Mature as sporocytststs in snail and cercariae are released into the water and penetrate human skin
- They lose their tail and enter the circulation as schistosimulae
- Migrate to portal blood in liver and mature into adults
- Adults pair and migrate toe bowel to lay eggs which are then excreted by the infected human
51
What are the clinical features of schistosomiasis?
```
Swimmers Itch (1st few hrs)
-Clears 24-48hrs
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Invasive stage (after 24hrs)
-Cough, abdominal discomfort, splenomegaly, eosinophilia
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Katayama Fever (after 15-20 days)
-Prostrate, fever, urticaria, lymphadenopathy, splenomegaly, diarrhoea, eosinophilia
```
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Acute disease (6-8 weeks)
-Eggs deposited in bowel (dysentery) or bladder (haematuria)
```
Chronic disease
52
How is schistosomiasis diagnosed?
- Clinical diagnosis
- Antibody tests
- Ova in stools and urine
- Rectal snip
53
How is schistomiasis treated?
PRAZIQUANTEL
-20mg/kg, two doses 6hrs apart
Prednisolone
-If severe
54
What doe rickettsiosis cause?
Tick typhus
55
What are the vectors involved in tick typhus?
- R. conorii
| - R. africae
56
What are the clinical features of tick typhus?
- Abrupt onset of swinging fever
- Headache
- Confusion
- Endovasculitis
- Rash (macular, petechial)
- Bleeding
57
How is tick typhus diagnosed?
- Clinical features
| - Serology
58
How is tick typhus treated?
Tetracycline
59
Give some examples of viral haemorrhagic fevers.
- Ebola
- Congo-Crimea haemorrhagic fever
- Lassa fever
- Marburg disease
60
What is the incubation of viral haemorrhagic fevers?
-Maximum incubation period is 3 weeks
61
How should people with viral haemorrhagic fevers be managed?
- High security infection unit in isolation
| - Supportive treatment
62
What pathogen causes zika?
Flavivirus
63
How is zika transmitted?
- Daytime biting aedes mosquitoes
| - Sexual contact with infected or infected blood transfusion
64
What conditions is zika related to?
- Dengue
- Yellow fever
- Jap B encephalitis
- West Nile virus
65
How can zike present?
- No or mild symptoms
- Headache
- Rash
- Fever
- Malaise
- Conjunctivitis
- Joint pains
66
What can zika virus cause in pregnancy?
Microcephaly and other neurological problems
67
How is zika managed?
- No current antiviral therapy
- Vaccines in development
- Prevention through mosquito control measures
68
What autoimmune condition can zika cause?
Guillain Barre syndrome
69
What is the most common cause of fever in a returning traveller?
Malaria
70
How can you narrow down your diagnosis when taking a history?
- Is it tropical?
- Travel history
- Precautions taken
- Risks
- Symptoms
- Incubation periods
71
What traveller disease would a rash suggest?
- Typhoid
- Typhus
- Dengue
72
What traveller disease would jaundice suggest?
- Hepatitis
- Malaria
- Yellow fever
73
What traveller disease would enlarged lymph nodes suggest?
- Leishmania
| - Trypanosomiasis
74
What traveller disease would hepatomegaly suggest?
- Malaria
- Typhoid
- Amoebic abscess
75
What traveller disease would splenomegaly suggest?
- Visceral leishmaniasis
- typhoid
- Malaria
76
What investigations should be carried out on a traveller returning with fever?
- FBC
- Malaria films
- LFTs
- Stool microscopy & culture
- Urine analysis & culture
- Blood culture(s)
- CXR
77
How should travellers returning with fever be treated?
- Isolation and use of PPE
- Supportive measures
- Empirical treatment if patient is unwell and based on the likely diagnosis
- Specific treatment once diagnosis is established
