WEEK 10 - The travel vaccination schedule Flashcards
Travel Vaccinations
Inc. examples, how to obtain them
- Before travelling contact GP who will do a risk assessment for you
- its not guaranteed will get vaccine
EXAMPLES:
- Polio
- Typhoid
- TB
- Yellow fever
- HepA, HepB
- Cholera
- Diphtheria
- Tetanus
- Dengue
- Rabies
- Japanese Encephalitis
- Meninigitis
- Tick-borne Encephalitis
Rabies INFO
Cause, Transmission
CAUSE: Lyssavirus
- has long incubation period (3-12 weeks)
TRANSMISSION: rabid animal bite or scratch
- direct contact (common) or aerosol
2 FORMS of RABIES:
1. Furious = 80% of cases
2. Paralytic (loss of limb function)
OTHER
- Once symptoms appear = fatal (99.9% likely to die)
Rabies: Pathogenesis
Starts in peripheral nervous system from bite (saliva) of infected animal
- Infected animal secretes virus in salivary glands
- Animal bites human + saliva makes contact with broken skin
- Virus gets taken up at the pre-synaptic cleft + gets endocytosed into peripheral nervous system (PNS)
- Virus travels through axonal transport to neuronal soma
- Virus replicates producing RNA, viral proteins etc.
- Viral proteins travels from PNS to CNS then to brain
- Once virus enters brain = able to enter salivary glands
- when bite someone = virus transmitted
Rabies: Symptoms
Initial infection:
(develop non-specific / prodrome symptoms)
- Fever
- Itchy skin
- Paraesthesia (i.e. tingiling)
As infection progresses:
- Confusion
- Hyperactivity
- Agitation
- Drowsiness
- Hypersalivaion
- Dysphagiea
Rabies: Vaccine
Have 1 licensed UK vaccine = Rabipur
- inc. vaccine + human rabies immunoglobulin (human serum from outside UK)
- can NOT use UK serum due to BSE risk
- Can be used as Pre-exposure immunisation or Post exposure management (PEM)
PEM:
- Is 99% effective
- Before PEM is given a risk assessment is done
- Needs to be given ASAP
Cholera INFO
Cause, Transmission, Symptoms
CAUSE: Vibrio Cholerae
- incubation period = hours to 5 days
TRANSMISSION: Water-borne
- ingestion of faecally contaiminated water
SYMPTOMS:
- Often asymptomatic but watery diarrhoea / rice water stools
Cholera: Pathogenesis
- V.cholerae enters + attaches to small intestine
- V.cholerae starts producing CtxA and CtxB (toxin)
- CtxB attaches to host epithelial, mediating uptake of toxin into host cell
- CtxA upregulates cAMP = ↑ CFTR (receptor) expression = ↑ movement of solutes from s.intestine into gut lumen
- ↑ movement of solutes from enterocytes into gut lumen causes diarrohea symptom
Cholera: Vaccinations / Treatments
Given to:
- AID workers
- Travellers to risk / outbreak areas
- Lab workers
Have 2 licensed UK vaccines:
1. Dukoral (inactivated)
- 85% efficacy
2. Vaxchora (live)
- 90.3% efficacy at 10 days
- 79.5% efficacy at 3 months
Typhoid Fever INFO
Cause, Transmission
CAUSE: Salmonella typhi
- incubation period is 3-56 days
- a human pathogen (disease only seen in humans) BUT can survive on surfaces for a while
- makes type 4 capsiles which stop complement-mediated killing + phagocytosis
TRANSMISSION: Oral consumption of contaminated food / water
- also via direct faecal oral route
Typhoid fever: Pathogeneisis
A systemic infection which invades GI tract
- S.typhi invades GI tracts + gets into blood and lymph nodes
- effects: liver, bone marrow, gall bladder - If gets into gall bladder = can be a chronic carrier for years
= asymptomatic but shed viable disease
- chronic carriers need antibiotics to remove infection - During acute infection you are shedding viable pathogen
= can cause contamination in other individual’s food, water supplies
= transmission of disease
Typhoid: Symptoms
Flu-like symptoms
- Fever
- Fatigue
- Headache
- Constipation
- Diarrhoea
- Rash
To confirm diagnosis: take a blood or faeces sample
Typhoid: Vaccinations and control
Vaccinations:
- Taken if travelling to typhoid endemic area
Several vaccines available e.g.
- VI polysaccharide vaccine
- Oral typhoid vaccine
Most areas are free from endemic typhoid due to:
- Public health measure
- Improved water supplies
- Good food standRDA
- Antibiotics
Dengue INFO
Cause, Transmission
CAUSE: Flavivirdae virus
- 3 to 14 days incubation period
TRANSMISSION: Aedes mosquito
OTHER:
- 80% infections are asymptomatic
Dengue: Symptoms
Usually asymptomatic
- Viraemia (blood enters virus) 4 days post bite
- Symptoms appear 5 days after bite
- fever
- muscle pain
- rash
- vomitting
- severe headache
Severe outcomes
- risk of multiple organ failure = vascular permeability
Dengue: Vaccinations / Treatment
Vaccination:
- Odenga - live attenuated vaccine
- NOTE: NOT advisable to recieve VACCINE if NOT had DENGUE BEFORE
- ↑ risk of severe outcomes if get infected witha diff. serotype of dengue after vaccination
- Vaccine is active against secondary infections NOT primary
- primary infections are less likely to be severe
Treatment:
- NO NSAIDs as they ↑ chances of bleeding
Japanese encephalitis INFO
Cause, Transmission
CAUSE: Flavivirus
- 4 to 14 day incubation period
TRANSMISSION: mosquitos
- mosquitos can trasnfer virus to pigs, horses and humans etc.
- horses + humans are ‘dead end’ hosts = can NOT transmit disease to others (virus level is NOT high enough)
- Pigs are secondary hosts = can transmit disease to farms, food etc.
Japanese encephalitis: Vaccination
Only 1 licensed UK vaccine = Ixiaro
- given 2 doses = 98%
- 1 dose alone = 20% efficacy
- can be used in 2months+
- Recommended if have a high risk of exposure due to travel / job
Treatment:
- No standard treatment
- Bite avoidance is encouraged e.g. insecticide, mosquito nets
Yellow Fever INFO
Cause, Transmission, Symptoms
CAUSE: Flavivirus
TRANSMISSION: mosquito-borne
- mosquitos can transmit virus to monkeys, humans etc.
SYMPTOMS:
Ranges in severity
- Can be subclinical
- Fever, malaise
- Moderate to severe disease (e.g. jaundice, liver/kidney impairment)
Yellow fever: Vaccination
No specific treatment but cases ↓ due to vaccines
Vaccine admisntered if:
- Lab worker
- Over 9 months + travelling to area with yellow fever risk
- Over 9 months travelling to country requring ICVP to enter
- Live attenuated vaccine
- only given to ages up to 59 (not ≥60)
- 1 dose = 95-100% efficacy
- ADRs are not common
