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Flashcards in Travel Related Infection Deck (57)
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1
Q

Why are travelers more vulnerable to infection?

A

They take risks they might not normally take (sex, water, food and animals)

They are in countries with different epidemiologies of disease (HIV, TB, polio and diptheria)

Incomplete understanding of health hazards

If the traveller is a refugee they may be deprived, malnourished, diseased or even injured.

2
Q

What are some infections that are common worldwide?

A

Influenza

Community acquired pneumonia

Meningococcal disease

Sexually transmitted disease

3
Q

What are some examples of climate or environmental related health problems?

A
  • Sunburn
  • Heat exhaustion and heatstroke
  • Fungal infections
  • Bacterial skin infections
  • Cold injury
  • Altitude sickness
4
Q

Give examples of some ifnections controlled by public health measures

A

Sanitation:

  • Travellers diarrhoea
  • Typhoid
  • Cholera
  • Viral gastroenteritis

Immunization:

  • Poliomyelitis
  • Diptheria

Education:

  • HIV
  • STD’s
5
Q

What are some water related infections?

A
  • Schistosomiasis
  • Leptospirosis
  • Liver flukes
  • Strongyloidiasis
  • Hookworms
  • Guinea worms
6
Q

Give examples of arthropod - borne infections

A

Malaria (mosquitos)

Dengue fever (mosquitos)

Leishmaniasis (sand flies: kala-azar)

Filariasis (mosquitos: elephantiasis)

7
Q

What are some emerging infections?

A

Zika - latin america, caribbean

Ebola virus - west africa

Avian flu - china

West Nile virus - USA

8
Q

What is the main vector of malaria?

A

Female anopheles mosquito

9
Q

What species is the potentially severe form of malaria?

A

Plasmodium falciparum

Bengn includes:

  • Plasmodium vivax
  • Plasmodium ovale
  • Plasmodium malariae
  • Plasmodium knowlesi
10
Q

What are the clinical features of malaria?

A

Symptoms:

  • •fever
  • rigors
  • aching bones
  • abdo pain
  • headache
  • dysuria
  • frequency
  • sore throat
  • cough
11
Q

What are the signs of malaria?

A

None

Splenomegaly

Hepatomegaly

Mild-jaundice

12
Q

What are the complications of malaria?

A

Cerebral malaria (encephalpathy) - coma

Blackwater fever - server intravascular haemolysis (high parasitaemia, profound anaemia, haemaglobulinuria, acute renal failure)

Pulmonary oedema

Jaundice

Severe anaemia

Algid malaria (gram negatice septicaemia)

13
Q

How is the diagnosis of malaria made?

A

•Thick & thin blood films

–Giemsa, Field’s stain

•Quantitative buffy coat (QBC)

–centrifugation, UV microscopy

•Rapid antigen tests

–OptiMal

–ParaSight-F

14
Q

On blood films you can see the parasite within the red blood cells

A
15
Q

What defines malaria as being complicated malaria?

A
  • Impaired consciousness or seizures
  • Hypoglycaemia
  • Parasite count greater than or equal to 2%
  • Haemoglobin less than or equal to 8mg/dL
  • Spontaneous bleeding / DIC
  • Haemoglobinuria
  • Renal impairment or pH <7.3
  • Pulmonary oedema or ARDS
  • Shock (algid malaria)

–?Gram negative bacteraemia

16
Q

What are the treatment options for uncomplicated plasmodium falciparum?

A

Riamet - 3 days

Eurartesim - 3 days

Malarone - 3 days

Quinine (plus oral doxycycline or clindamycin) - 7 days

17
Q

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

A

IV artesunate (unlicensed in the UK)

IV quinine (plus oral doxycycline or clindamycin)

18
Q

What is treatment of P. vivax, p.ovale. p. malariae, p.knowlesi?

A

Chloroquine for 3 days

Riamet - 3 days

Add primaquine (14 days) in vivax and ovale tp eradicate liver hypnozoites

Before using primaquine you need to check for G6PD deficiency

19
Q

What are malaria control programmes?

A

•Mosquito breeding sites

–Drainage of standing water

•Larvacides

–(Paris green), temphos, biological

•Mosquito killing sprays

–DDT, malathion, (dieldrin)

•Human behaviour

–Bed nets

–Mesh windows

20
Q

What are the causative organisms for typhoid?

A

Salmonella typhi

Salmonella paratyphi

21
Q

What are the clinical features of typhoid?

A

•Incubation period: 7 days - 4 week

•1st week:
fever, headache, abdo. discomfort, constipation, dry cough, relative bradycardia, neutrophilia, confusion

•2nd week:
fever peaks at 7-10 days, Rose spots, diarrhoea begins, tachycardia, neutropenia

•3rd week (Complications):
intestinal bleeding, perforation, peritonism, metastatic infections

•week 4 (Recovery):
10 - 15% relapse

22
Q

How is the diagnosis of typhoid fever made?

A

•Clinical

–not easy

–evolution of features

•Laboratory (Salmonella typhi, S. paratyphi)

–Culture blood, urine & stool

–Culture bone marrow

23
Q

What is the treatment for typhoid fever?

A

Oral azithromycin

IV ceftriaxone - if complicated or concerned regarding absorption

24
Q

What is the commonest human arbovirus infection?

A

Dengue

25
Q

What causes the transmission of dengue?

A

Aedes aegypti

26
Q

What is the classical presentation of dengue fever?

A
  • Sudden fever
  • Severe headache, retro-orbital pain
  • Severe myalgia and arthralgia
  • Macular/ maculopapular rash
  • Haemorrhagic signs: petechiae, purpura, positive tourniquet test
27
Q

What is the tourniquet test? What does it assess?

A

It assesses a patients haemorrhagic tendancy and capillary fragility. It is part of the WHO algorith for diagnosis of dengue fever.

A blood pressure cuff is applied and inflated to the midpoint between the systolic and diastolic blood pressures for five minutes. The test is positive if there are more than 10 to 20 petechiae per square inch

28
Q

What is the clinical and laboratory diagnosis of dengue?

A

Clinical:

–Thrombocytopenia

–Leucopenia

–Elevated transaminases

–Positive tourniquet test

Laboratory - PCR, serology

29
Q

What are the therapeutic agents for dengue fever?

A

No specific therapeutic agents

30
Q

What are the complications for dengue?

A

–Dengue haemorrhagic fever (DHF)

–Dengue shock syndrome (DSS)

Rx: IV fluids, fresh frozen plasma, platelets

31
Q

What are the prevention methods for dengue?

A

Avoid bites

New vaccine (dengvaxia), 2016 limited use

32
Q

What are the transmitting organisms for schistosomiasis?

A

Freshwater snails

33
Q

What are the micro-organisms assocaited with schistosomiasis?

A
  • S. haematobium
  • S. mansoni
  • S. japonicum
34
Q

What is the schistosomiasis life cycle?

A

Eggs hatch releasing miracidia

Miracidia penetrate snail tissue

Sporocysts form in snail tissue

Sporocysts form cercariae which can penetrate human skin

Circariae shed their forked tail forming schistosomulae

Schistosomulae reside in the veins of the human host

Eggs are eliminated in faeces of urine

35
Q

What are the clinical features of schistosomiasis?

A

•Swimmers Itch (1st few hrs)

–clears 24-48hrs

•Invasive stage (after 24hrs)

–cough, abdo 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

36
Q

What is the diagnosis of schistosomiasis?

A

–Clinical diagnosis

–Antibody tests

–Ova in stools and urine

  • Rectal snip
37
Q

What is the treatment for schistosomiasis?

A

–PRAZIQUANTEL 20mg/kg, 2 doses 6hrs apart

–Prednisolone if severe

38
Q

What diseases is caused by tick typhus, give an example of the causative organism

A

Rickettsiosis

R. Conorii

39
Q

What are the clinical features of rickettsiosis?

A

Abrupt onset, swinging fever, headache, confusion, endovasculitis, rash (macular, petechial), bleeding

40
Q

What is the diagnosis of rickettsiosis?

A

Clinical features

Serology

41
Q

What is the management of rickettsiosis?

A

Tetracycline

42
Q

Give examples of viral haemorrhagic fevers

A

Ebola

CCHV - crimean congo haemorrhagic fever

Lassa fever

Marburg disease

43
Q

What is the primary prevention method for spread of viral haemorrhagic fevers?

A

High security infection unit

Treatment is supportive

44
Q

What virus causes Zika?

A

Flavivirus

45
Q

What transmits the zika virus?

A

Daytime - biting aedes mosquitos

Also by sexual contact, blood transfusion

•Related to dengue, yellow fever, Jap B encephalitis and West Nile viruses

46
Q

What geographical areas were associated with outbreaks of zika virus?

A

Pacific outbreak - 2013-2014

Latin america pandemic 2015 - 2016

47
Q

What are the clinical features of zika virus?

A

•Clinical: no or mild symptoms - headache, rash, fever, malaise, conjunctivitis, joint pains (like dengue)

In pregnancy can cause microcephaly and other neurological symptoms

Can cause guillain-barre syndrome

48
Q

What are the control measures for Zika?

A
  • No antiviral therapy
  • Mosquito control measures
  • Vaccines in development
49
Q

What is the most likely causes of fever in the patient returning from travel?

A

Malaria

50
Q

What travel disease might a rash be a sign of?

A

typhoid, typhus, dengue

51
Q

What might jaundice be a sign of?

A

Hepatitis

Malaria

Yellow fever

52
Q

What might lymphadenopathy be a sign of?

A

leishmania, trypanosomiasis

53
Q

What might enlarged liver be a sign of?

A

malaria, typhoid, amoebic abscess

54
Q

What might splenomegaly be a sign of?

A

•visceral leishmaniasis, typhoid, malaria

55
Q

Investigations

A
  • FBC
  • malaria films
  • liver function tests
  • stool microscopy & culture
  • urine analysis & culture
  • blood culture(s)
  • CXR
56
Q

Specific tests as indicated

A

–dengue

–respiratory viral/atypical

–hepatitis A, B, C

–tick typhus (Rickettsia)

–schistosomiasis

–amoebic

–leptospirosis/hantavirus

–viral haemorrhagic fevers

57
Q

Treatment

A
  • Isolation: ?personal protective equipment
  • Supportive measures (resuscitation)
  • Empirical treatment if patient unwell

–Antimicrobial therapy based on likely diagnosis

–aim to treat life-threatening conditions
e.g. typhoid, septicaemia

•Specific treatment

– once diagnosis is established