Travel Related Infection Flashcards
1
Q
What is heat exhaustion?
A
Inability to maintain CO with normal CNS function (core body temp not above 40C)
2
Q
What is heat stroke??
A
Life-threatening condition in which body temp exceeds 41.1C because of in imbalance in heat generation and dissipation
3
Q
What are climate/environment associated health problems travellers may be exposed to?
A
Sunburn Heat stroke/exhaustion Fungal infections Bacterial skin infections Cold injury Altitude sickness
4
Q
What causes altitude sickness?
A
Hypoxaemia from low O2 levels
5
Q
What are the symptoms of altitude sickness?
A
Headache, NV, fatigue, weakness, pitting oedema, epistaxis, dyspnoea
6
Q
What diseases are controllable by improved sanitation?
A
Traveller’s diarrhoea, typhoid, hep A and E, giardiasis, amoebiasis, helminth infections, viral gastroenteritis, food poisoning, shigella dysentery, cholera, cryptosporidosis
7
Q
What diseases are preventable by immunisation?
A
Polio, diphtheria
8
Q
What diseases are preventable by education?
A
HIV/STIs
9
Q
What water related infections are assoc. with travel?
A
Schistosomiasis Leptospirosis Liver flukes Strongyloidiasis Hookworms Guinea worms
10
Q
What is schistosomiasis?
A
Parasitic disease caused by schistosomes (trematode)
Infection occurs when skin comes into contact with parasite infected water
11
Q
What is leptospirosis?
A
Infection with leptospira bacteria
Direct transmission to humans when broken skin/mucous membranes come into contact with infected animal urine, e.g. rodents
Usually self-limiting, may progress to Weil’s disease
12
Q
What are the three things assoc. with Weils disease?
A
AKI, jaundice, bleeding
13
Q
What are liver flukes?
A
Parasitic trematode which are principally parasites of the liver
14
Q
What is strongyloidiasis?
A
Nematode
Usually only seen in those returning from wet tropical areas
15
Q
What are hook worms?
A
Intestinal roundworm parasites
16
Q
What are guinea worms?
A
Worms residing in s/c tissue
Eventually emerges from the feet in most cases
17
Q
What are the arthropod-borne infections?
A
Malaria Dengue fever Rickettsial infection Leishmaniasis Trypanosomiasis Filarisis Onchocericiasis
18
Q
What is malaria and dengue fever spread by?
A
Mosquitos
19
Q
What is rickettsial infection spread by?
A
Ticks
Causes typhus
20
Q
What transmits leishmaniasis?
A
Sand fly bite
21
Q
What is the presentation of leishmaniasis?
A
Cutaneous/visceral manifestation
Most important visceral manifestation is kala-azar (weight loss, hepatosplenomegaly, immunosuppression)
22
Q
What is typanosomiasis transmitted by?
A
Tsetse fly
23
Q
What does trypanosomiasis cause?
A
Sleeping sickness (somnolence, coma, lymphadenopathy, recurrent fever)
24
Q
What is filariasis spread by?
A
Mosquitos
25
What does filariasis cause?
Elephantiasis (enlargement and swelling of the lower limbs)
26
What is onchoceriasis spread by?
Black flies
27
What does onchoceriasis cause?
River blindness
28
What are the emerging infectious diseases assoc. with travel?
```
Zika virus (Latin America, carribbean)
Ebola (w. Africa)
MERS-CoV (middle east)
Swine flu (H1N1)
Avian flu (H5N1)
SARS (far east)
West nile virus (USA)
```
29
What causes malaria?
Plasmodium species
30
What is required for a country to be able to be at risk of malaria?
Mosquitos bread in stagnant water - so req. high rainfall, high humidity and temperature
31
What is the vector for malaria?
Female anopheles mosquito
Male feeds on nectar
Females req. nutrition from blood for development of their eggs
32
How do mosquitos know how to get to blood?
Follow CO2 and bodily smells
33
What is the lifecycle of malaria?
Blood meal from non-infected human by infected mosquito - sporozite enters human's blood stream
Via bloodstream, sporozite travels to liver, where they reproduce in hepatic cells and mature into merozoites (host parenchymal cells die)
Merozites released in blood (invade RBCs & reproduce to produce lots of merozites --> bursting of RBCs) (this is the erythrocytic phase)
Merozites either re-enter erythrocytic phase or divide and give rise to gametes
Gametes can then be sucked up by uninfected female anopheles mosquito
Gametes fuse in mosquitos gut --> zygote
Zygote develops and eventually releases lots of sporozites which make their way to the salivary gland --> repeat whole process
34
What are the species of plasmodium?
Plasmodium falciparum (potentially severe)
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi (bottom 4 cause benign malaria)
35
What are the clinical features of malaria?
```
Short bursts of fever
Headache
NV
Rigors
Aching bones/muscles
Abdominal pain
Dysuria
Frequency
Sore throat
Dry cough
Splenomegaly
Hepatomegaly
Mild jaundice
```
Most plasmodium infections have a mild course of symptoms and are considered uncomplicated malarial infections
36
What are the two types of complicated malaria?
Cerebral malaria
| Blackwater fever
37
What occurs in cerebral malaria?
Brain is affected (haemolytic anaemia --> brain not getting enough oxygen)
Infarcts in brain tissue may result as parasited RBCs block off BVs --> ischaemia
38
What is the presentation of cerebral malaria?
Altered mental status, convulsions, seizures, coma
| May also see gross arching of the back which is a sign of severe meningism
39
In which group of people is cerebral malaria most common?
Non-immune visitors and children
40
What does blackwater fever result from?
Severe intravascular haemolysis due to high parasitaemia leads to profound anaemia and Hb is released directly into BVs and urine
Often leads to AKI
41
What are the clinical features of blackwater fever?
Pulmonary oedema, jaundice, severe anaemia, algid anaemia (gram -ve septicaemia with malaria)
42
How do you manage malaria?
Mild - chloroquine
| More serious - ITU and artesunate
43
How do you diagnose malaria?
Thick and thin blood films (+/- giemsa, field stain)
Quantitative buffy coat
Rapid antigen tests
44
What will you see on the thick and thin blood films for malaria?
RBCs with signet rings inside them
| Multiple parasites in RBCs
45
What does quantitative buffy coat involve in malaria diagnosis?
Centrifugation to bring RBCs to the bottom and plasma to the top
UV microscopy under fluorescent light will allow for visualiation of parasites
46
What are the rapid antigen tests you can do for malaria?
OptiMal
ParaSight-F
Drop blood at one end of device - chemical reaction will tell you whether it is falciparum or not
47
Complicated malaria = ?
```
1+ of:
Impaired consciousness/seizures
Hypoglycaemia
Parasite count 2%+
Hb 8 or less
Spontaneous bleeding/DIC
Haemoglobulinuria
Renal impairment or pH <7.3
Pulmonary oedema or ARDS
Shock (algid malaria)
```
48
How do you treat uncomplicated falciparum infection?
Riamet (artemether-lumefantrine) 3 days
Eurartesim (dihydroartemisin-piperaquine) 3 days
Malarone (atovaquone-proguanil) 3 days
Quinine 7 days + oral doxycycline or clindaymycin
49
How do you treat complicated falciparum?
IV artesunate
IV quinine & doxycycline/clindamycin
Parasite count >10% then exchange transfusion should be considered
50
How do you treat P. vivax/ovale/malariae/knowlesi?
Chloroquine 3 days
Riamet 3 days
Add primaquine (14d) if vivax & ovale to get rid of liver hypnozites
51
When prescribing riamet/eurartesim/malarone what must you check?
G6PD deficiency as can lead to anaemia in these patients
52
What are the side effects of quinine?
Nausea, tinnitus, deafness, rash, hypoglycaemia, cardiac depression, cerebral irritation??
53
What are the malaria control programmes?
Mosquito breeding sites drainage
Larvicides - biological, temphos
Mosquito killing sprays (DDT)
Human behaviour - bed nets, mesh windows
54
What causes typhoid (enteric fever)?
Infectious disease caused by faecal-oral transmission of salmonella
55
What are the two species of salmonella that cause typhoid fever?
Salmonella typhi and salmonella paratyphi
56
What is the incubation period of typhoid fever?
7 days - 4 weeks
57
What is the presentation of typhoid fever/
wk1 - headache, fever, discomfort, constipation, dry cough, relative bradycardia, neutrophilia, confusion
wk2 - fever peaks, rose spots (chest, abdo), diarrhoea, begins, tachycardia, neutropenia
wk3 - clinical features of wk 2 + complications (e.g. intestinal bleeding, perforation, peritonism, metastatic infections)
wk4 - recovery for most
58
What tests can help you diagnose typhoid fever?
Culture blood, urine and stool
| Diagnosis made on blood culture!
59
How do you treat typhoid fever?
```
Oral azithromycin (uncomplicated)
IV ceftriaxone (complicated)
```
60
What is dengue fever?
Infection with dengue virus
| Can progress to viral haemorrhagic fever
61
What is the presentation of dengue fever in most people?
Mild and passes without lasting problems in about a week
62
What species of mosquito carries the dengue virus?
Aedes aegypti species
63
When do the Aedes aegypti species of mosquito tend to bite?
During the day or early evening before dusk
64
Where are Aedes aegypti mosquitos often found?
Living around sources of stagnant water, e.g. wells/water tanks
65
What is the classical presentation of dengue fever?
```
Sudden fever
severe headache, retro-orbital pain
Severe myalgia/arthalgia
Maculopapular rash
Facial flushing
Pleuritic pain
```
66
What is potentially life-threatening dengue fever called? What are its clinical manifestations?
```
Dengue haemorrhagic fever (form of DIC)
Severe abdominal pain
Abdominal swelling
Persistent vomiting (of blood)
Difficulty breathing
Cold, clammy skin
Purpura, petechiae
Positive tourniquet test
```
67
What does a tourniquet test determine?
Capillary fragility & hence haemorrhagic potential
68
How do you diagnose dengue fever?
Clinically - thrombocytopenia, leucopenia, elevated transaminases, positive tourniquet test
PCR and serology in the lab ca help
69
How do you manage dengue fever?
Fluids and paracetamol
| Complications: DHF & dengue shock syndrome (circulatory failure & DHF) - fluids, FFP, platelets
70
How do you prevent dengue fever?
Avoid bites
| New vaccine - limited use
71
What is schistosomiasis?
Infection with schistosomes (flatworms)
72
When should you think schistosomiasis?
Traveller returning with haematuria or dysentry
73
Where is schistosomiasis most common?
Rural areas with freshwater sources and poor sanitation
74
What are the species of schistosomes?
S. haematobium
S. mansoni
S. japonicum
75
What is the life cycle of the schistosomes?
Infected human excretes schistosome eggs in urine/faeces
Eggs hatch in water and release miracidia
Miracidia infect fresh water snails (intermediate hosts) where they develop into cercaria and are released back into the water
When humans come into contact with contaminated water - cercaria can penetrate and enter circulation
Migration into portal blood and liver where they mature into adults
Paired adult worms migrate into mesenteric venules of bowel/rectum (laying eggs that circulate to liver and shed n the stools) or venous plexus of bladder depending on species
76
What are the clinical features of schistosomiasis?
```
Swimmer's itch (first few h) - clears after 24-48h
Invasive stage (after 24h) - cough, abdo discomfort, splenomegaly, eosinophilia
Katayama fever (after 15-20 days) - prostrate, fever, urticaria, lymphadenopathy, splenomegaly, diarrhoea, eosinophilia
Acute disease (6-8wks) - eggs deposited in bowel (dysentery) or bladder (haematuria)
```
Chronic disease (tends not to occur in travellers, but can lead to neurological problems)
77
How do you diagnose schistosomiasis?
Clinical diagnosis
Antibody tests
Ova in stools/urine
Rectal snip
78
How do you treat schistosomiasis?
Praziquantel 20mg/kg, 2 doses 6h apart
| Prednisolone to dampen symptoms
79
What is ricketsiosis/typhus?
Infection of 1+ ricketsial bacteria transmitted by fleas, lice, ticks, mites
80
What species cause tick typhus?
R. conorri, R. africae
81
What species cause rocky mountain spotter fever?
R. richettsii
82
What species cause endemic typhus?
R. prowazekii
83
What species causes murine/endemic typhus?
R. Mooseri
84
What species causes scrub typhus?
R. tsutsugamushi
85
What are the clinical features of tick typhus?
Abrupt onset swinging fever, headache, confusion, endovasculitis, rash (macular, petechial), bleeding
86
How do you diagnose tick typhus?
Clinical, serology
87
How do you manage tick typhus?
Tetracycline
88
What are the viral haemorrhagic fever?
Ebola
Congo-Crimea haemorrhagic fever
Lassa fever
Marburg disease
89
What is the maximum incubation period of the viral haemorrhagic fevers?
3 weeks
90
How do you manage people with viral haemorrhagic fevers?
Rule out common severe infections, Rx supportive
91
What kind of virus is vika virus?
Flavivirus
92
What is zika virus transmitted by?
Day time biting by Aedes mosquito
| Also spread by sexual contact and blood transfusion
93
What are the clinical features of zika virus?
None/mild - headache, rash, fever, malaise, conjunctivitis, joint pains
GB syndromes
94
In pregnancy what can zika virus lead to?
Microencephaly, other neurological problems
95
How do you Rx zika virus?
No antivirals
| Mosquito control measures
96
What should you be aware of in trying to diagnose fever in a returning traveller?
It is most likely not tropical fever, e.g. just influenza
97
What history should you take in fever in returning traveller?
Travel hx
Precautions taken
Risk
Symptoms
98
What travel related infections will you see a rash in?
Typhoid
Typhus
Dengue
99
What travel related infections will you see jaundice in?
Yellow fever
Malaria
Hepatitis
100
What travel related infections will you see lymphadenopathy in?
Leishmaniasis, trypanosomiasis
101
What travel related infections involve the liver?
Malaria, typhoid, amoebic abscess
102
What travel related infections involve the spleen?
Visceral leishmaniasis, typhoid, malaria
103
What things may mean people are protected from malaria?
Sickle cell trait
G6PD deficiency
HLA-B53
Absence of Duffy antigens
104
What are different malaria prophylaxis regimens?
Atovaquone + proguanil (malarone)
Chloroquine
Doxycycline
Mefloquine (lariam)
Proguanil (paludrine)
Proguanil + chloroquine
105
What are SEs of malarone?
GI upset
106
What are SEs of chloroquine?
Headache
CI in epilepsy
NB take weekly
107
What are SEs of doxycyline?
Oesophagitis
| Photosensitivity
108
What are SEs of lariam?
Dizziness
Neuropsychiatric disturbance
CI in epilepsy
NB also take weekly
109
What advice should be given to pregnant woman re. malaria?
Avoid travelling to regions where it is endemic
If not -
Chloroquine can be used
Proguanil can only be taken with folate 5mg supplementation
Avoid others
110
What are the criteria for severe falciparum malaria?
```
High parasitaemia (>2%)
Hypoglycaemia
Severe anaemia
Renal failure
Pulmonary oedema
Metabolic acidosis
Abnormal bleeding
Multiple convulsions
Seizures
Shock
```
111
What is yellow fever?
A type of viral haemorrhagic fever spread by the Aedes mosquito
112
What are the features of yellow fever?
Flu like illness lasting <1 week
High fever, rigors, NV, bradycardia
Brief remission, followed by jaundice, haematemesis, oliguria
Councilman bodies may be seen in hepatocytes
113
What vaccines are routinely offered to pregnant women?
Flu and pertussis
