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)
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2
Q

What infections are common worldwide?

A
  • Influenza
  • Community acquired pneumonia
  • Meningococcal disease
  • Sexually transmitted diseases
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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
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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
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5
Q

What infections are controllable by public heath measures regarding immunisations?

A
  • Poliomyelitis

- Diphtheria

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6
Q

What infections are controllable by public heath measures regarding education?

A
  • HIV

- STDs

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7
Q

Give examples of water-related infections

A
  • Schistosomiasis
  • Leptospirosis
  • Liver flukes
  • Strongyloidiasis
  • Hookworms
  • Guinea worms
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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)
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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
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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
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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
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12
Q

What is the malaria vector?

A

The female anopheles mosquito

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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
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14
Q

What are the 5 species of malaria?

A

Potentially severe
-Plasmodium falciparum

Benign

  • Plasmodium vivax
  • Plasmodium ovale
  • Plasmodium malariae
  • Plasmodium knowlesi
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15
Q

What symptoms can malaria present with?

A
  • Fever
  • Rigors
  • Aching bones
  • Abdominal pain
  • Headache
  • Dysuria
  • Frequency
  • Sore throat
  • Cough
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16
Q

What signs can malaria present with?

A
  • None
  • Splenomegaly
  • Hepatomegaly
  • Mild jaundice
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17
Q

What are the possible complications of malaria?

A
  • Cerebral malaria (encephalopathy)
  • Blackwater fever
  • Pulmonary oedema
  • Jaundice
  • Severe anaemia
  • Algid malaria
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18
Q

How does cerebral malaria present?

A
  • Hypoglycaemia
  • Convulsions
  • Hypoxia
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19
Q

How does Blackwater fever present?

A
  • Severe intravascular haemolysis
  • High parasitaemia
  • Profound anaemia
  • Haemoglobulinuria
  • AKI
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20
Q

What is algid malaria?

A

Gram negative septicaemia

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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
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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)
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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
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24
Q

What are the possible side effects of oral quinine?

A
  • Nausea
  • Tinnitus
  • Deafness
  • Rash
  • Hypoglycaemia
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25
Q

What are the treatment options for complicated or severe P falciparum malaria?

A
  • IV artesunate

- IV quinine plus oral doxycycline or clindamycin

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26
Q

What are the possible side effects of IV quinine?

A
  • Cardiac depression
  • Cerebral irritation
  • N+V
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27
Q

How is malaria caused by organisms other than P falciparum treated?

A
  • Chloroquine (3 days)
  • Riamet (3 days)
  • Add primaquine (14 days) in vivax and ovale to eradicate liver hypnozoites
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28
Q

What programmes are there in place to control malaria?

A
  • Drainage of standing water to prevent mosquito breeding sites
  • Larvacides
  • Mosquito killing sprays
  • Human behaviour including bed nets and mesh windows
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29
Q

What organisms cause typhoid (enteric) fever?

A
  • Salmonella typhi

- Salmonella paratyphi

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30
Q

What is the epidemiology of typhoid?

A
  • Global cases: 27 million infections/yr
  • Global deaths:over 200,000/yr
  • UK cases: 500/yr
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31
Q

What conditions make typhoid more likely?

A
  • Poor sanitation

- Unclean drinking water

32
Q

What is the incubation period for typhoid?

A

7-28 days

33
Q

What are the clinical features of typhoid within the 1st week?

A
  • Fever
  • Headache
  • Abdominal discomfort
  • Constipation
  • Dry cough
  • Relative bradycardia
  • Neutrophilia
  • Confusion
34
Q

What are the clinical features of typhoid in the 2nd week?

A
  • Fever peaks at 7-10 days
  • Rose spots
  • Diarrhoea begins
  • Tachycardia
  • Neutropenia
35
Q

What are the clinical features of typhoid in the 3rd week?

A
  • Intestinal bleeding
  • Perforation
  • Peritonism
  • Metastatic infections
36
Q

What are the clinical features of typhoid in week 4?

A
  • Usually recovery

- 10-15% relapse

37
Q

How is typhoid fever diagnosed?

A
  • Clinically not easy due to evolution of features
  • Culture of blood, urine and stool
  • Culture of bone marrow
38
Q

What is the treatment for typhoid fever?

A
  • Oral azithromycin

- IV ceftriaxone

39
Q

What is the commonest human arbovirus infection?

A

Dengue

40
Q

What is the epidemiology of Dengue fever?

A
  • Dengue infection: 100 million cases/year

- Dengue Deaths: 25,000/year

41
Q

What is the vector in dengue?

A

Aedes aegypti (mosquito)

42
Q

What is the classical presentation of dengue?

A
  • Sudden fever
  • Severe headache, retro-orbital pain
  • Severe myalgia and arthralgia
  • Macular/ maculopapular rash
  • Haemorrhagic signs: petechiae, purpura, positive tourniquet test
43
Q

How is dengue diagnosed?

A

Clinically

  • Thrombocytopenia
  • Leucopenia
  • Elevated transaminases
  • Positive tourniquet test

Laboratory

  • PCR
  • Serology
44
Q

How is dengue managed?

A

No specific therapeutic agents

45
Q

What are the possible complications of dengue?

A
  • Dengue haemorrhagic fever (DHF)

- Dengue shock syndrome (DSS)

46
Q

How are the complications associated with dengue managed?

A
  • IV fluids
  • Fresh frozen plasma
  • Platelets
47
Q

How is dengue prevented?

A
  • Avoid bites

- New vaccine but limited use

48
Q

What vectors are involved in schistosomiasis?

A
  • S. haematobium
  • S. mansoni
  • S. japonicum
49
Q

How is schistosomiasis transmitted?

A

Freshwater snails

50
Q

Describe the lifecycle of schistosomiasis.

A
  • 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
Q

What are the clinical features of schistosomiasis?

A
Swimmers Itch (1st few hrs)
-Clears 24-48hrs 
Invasive stage (after 24hrs)
-Cough, abdominal discomfort, splenomegaly, eosinophilia
Katayama Fever (after 15-20 days)
-Prostrate, fever, urticaria, lymphadenopathy, splenomegaly, diarrhoea, eosinophilia
Acute disease (6-8 weeks)
-Eggs deposited in bowel (dysentery) or bladder (haematuria)

Chronic disease

52
Q

How is schistosomiasis diagnosed?

A
  • Clinical diagnosis
  • Antibody tests
  • Ova in stools and urine
  • Rectal snip
53
Q

How is schistomiasis treated?

A

PRAZIQUANTEL
-20mg/kg, two doses 6hrs apart

Prednisolone
-If severe

54
Q

What doe rickettsiosis cause?

A

Tick typhus

55
Q

What are the vectors involved in tick typhus?

A
  • R. conorii

- R. africae

56
Q

What are the clinical features of tick typhus?

A
  • Abrupt onset of swinging fever
  • Headache
  • Confusion
  • Endovasculitis
  • Rash (macular, petechial)
  • Bleeding
57
Q

How is tick typhus diagnosed?

A
  • Clinical features

- Serology

58
Q

How is tick typhus treated?

A

Tetracycline

59
Q

Give some examples of viral haemorrhagic fevers.

A
  • Ebola
  • Congo-Crimea haemorrhagic fever
  • Lassa fever
  • Marburg disease
60
Q

What is the incubation of viral haemorrhagic fevers?

A

-Maximum incubation period is 3 weeks

61
Q

How should people with viral haemorrhagic fevers be managed?

A
  • High security infection unit in isolation

- Supportive treatment

62
Q

What pathogen causes zika?

A

Flavivirus

63
Q

How is zika transmitted?

A
  • Daytime biting aedes mosquitoes

- Sexual contact with infected or infected blood transfusion

64
Q

What conditions is zika related to?

A
  • Dengue
  • Yellow fever
  • Jap B encephalitis
  • West Nile virus
65
Q

How can zike present?

A
  • No or mild symptoms
  • Headache
  • Rash
  • Fever
  • Malaise
  • Conjunctivitis
  • Joint pains
66
Q

What can zika virus cause in pregnancy?

A

Microcephaly and other neurological problems

67
Q

How is zika managed?

A
  • No current antiviral therapy
  • Vaccines in development
  • Prevention through mosquito control measures
68
Q

What autoimmune condition can zika cause?

A

Guillain Barre syndrome

69
Q

What is the most common cause of fever in a returning traveller?

A

Malaria

70
Q

How can you narrow down your diagnosis when taking a history?

A
  • Is it tropical?
  • Travel history
  • Precautions taken
  • Risks
  • Symptoms
  • Incubation periods
71
Q

What traveller disease would a rash suggest?

A
  • Typhoid
  • Typhus
  • Dengue
72
Q

What traveller disease would jaundice suggest?

A
  • Hepatitis
  • Malaria
  • Yellow fever
73
Q

What traveller disease would enlarged lymph nodes suggest?

A
  • Leishmania

- Trypanosomiasis

74
Q

What traveller disease would hepatomegaly suggest?

A
  • Malaria
  • Typhoid
  • Amoebic abscess
75
Q

What traveller disease would splenomegaly suggest?

A
  • Visceral leishmaniasis
  • typhoid
  • Malaria
76
Q

What investigations should be carried out on a traveller returning with fever?

A
  • FBC
  • Malaria films
  • LFTs
  • Stool microscopy & culture
  • Urine analysis & culture
  • Blood culture(s)
  • CXR
77
Q

How should travellers returning with fever be treated?

A
  • 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