Week 5 Travel Related Infections Flashcards
(24 cards)
Name some common travel related infections
Malaria Typhoid Meningococcal septicaemia- non travel related infection Dengue Yellow fever
Apply the infection model to a pt presenting with an infection linked to travel?
Patient
- person- age, gender, physiological, pathological and social factors (low income country)
- time- CALENDAR TIME, RELATIVE TIME
- place- current, RECENT
Why is a travel history so important?
- Imported diseases- rare/unknown in UK
- Different strains of pathogens-antigenically different, impact on protection and detection, AB resistant
- infection prevention- on ward and in lab
Describe the incubation period and symptoms of malaria
incubation period- 1-3 weeks after bite- differs with species
sympts- Fever, shaking, sweating, headache, fatigue, dry cough, nausea, vomiting, spenomegaly at first and progressively getting worse.
What are the 4 key aspects of the travel history and name some other things to consider?
WHERE- sub saharan africa , SE asia, S/C America must risky WHEN- did sympts begin WHAT- are the signs/sympts HOW- did they acquire it? Accommodation How long Specific risks- sexual contacts Foreign healthcare exposures Preventive measures, vaccines
Describe the 4 main species of malaria
Plasmodium - falciparum (most dangerous), vivax, ovale, malariae
Describe the bacteria causing enteric fever (typhoid and paratyphoid) and how it is contracted
bacteria- salmonella typhi/ paratyphi A,B or C
- aerobic gram -ve rod - similar to e coli and others found in bowel
- virulence- invasin- allows intracellular growth, fimbtiae- adhesion, peyers patch- lymphoid tissues- pass through bowel
mainly from asia, africa and S america
due to poor sanitation
faecal oral transmission- contaminated food- street food, water
Where and how do you look up information of travel related infections?
public health england
WHO
interhealth worldwide
Describe influenza virus and its transmission
RNA viruses
influenza virus A, B or C
influenza A- wild birds are the natural host- occasionally transmitted to other species and may cause outbreaks in domestic poultry and give rise to human pandemics
- most virulent human pathogen
- has different serotypes based on antibody response to the virus
influenza B- affects humans most, less common, 1 serotype- immunity often acquired at young age but mutations enough
influenza C- humans, dogs, pigs, less common, mild disease in children
transmission- direct- sneeze mucus into eye, nose, mouth
- aerosols- coughing
- hand to; eye, nose or mouth
Describe legionella pneumophilia and an example of its clinical importance
- aerobic bacillus gram -ve bacterium - found in aquatic systems
- causes legionnaires disease - atypical pneumonia
- inhalation of aerosolised water, NOT airborne or person to person
- bacteria invades macrophages and lung epithelial cells and reproduces within these infected cells
- incubation 2-10 days
- sympts- fever, chills, cough- dry or sputum, can be blood, muscle aches, headache, tired, loss of appetite, loss of coordination, chest pain, D&V
- half people have GI symps and have have neurological sympts- confusion, impaired cognition
- abnormal kidney function, LFT, and electrolytes, CXR
what are the 3 main WHERE places to consider?
sub-saharan africa, SE asia, S/C America
what are the different time categories relating to when symptoms begin?
> 10days acute
10-21 subacute
21 chronic
what are some of the possible signs and symptoms of infectious disease?
resp- SOB/cough
GI-diarrhoea
Skin-rash
Jaundice- pre or post hepatic
CNS- headache/ meningism
Lymphoreticular- lymphadenopathy- glands increase in size in neck and groin/ spenomegaly- part of reticular endothelial system
Eosinophilia- eosinophils should not be raised- if are could be due to asthma, large increase- helminth disease
what are the main HOW a person acquires an infectious disease and give an example of each?
food/water- Travellers diarrhoea insect/tick bite- malaria swimming- helminth infections sexual contact- hep A animal contact (bite/safari)- tick bites, rabies beach/ recreational activities
what common investigations might you do in order to diagnose an infectious disease?
FBC- HB- may be low, WCC- low, platelets- low
Biochemistry- urea, creatinine-high, bilirubin- high, LFT, CRP- high
what might you see on a blood film of someone with malaria?
nodules on RBCs and dark spots
how is malaria contracted?
vector- female anopheles mosquito
no case to case spread
describe some of the severe symptoms that may arise as a result of falciparum malaria?
- cardiovascular- tachycardia, hypotension, arrhythmias
- respiratory- ARDS- acute respiratory distress syndrome- lungs filled with fluid
- GIT- diarrhoea, deranged LFT, bilirubin
- Renal- acute kidney injury
- CNS- confusion, fits, cerebral malaria (microvascular occlusion)
- blood- low/normal WCC, thrombocytopenia, DIC
- metabolic- Metabolic acidosis, hypoglyceamia
what are the investigations and treatments commonly used for malaria?
investigations: blood smear x3- thick- detect virus and thin- detect species FBC, U&E, LFT, glucose, coagulation head CT is CNS sympts CXR- respiratory distress syndrome
Treatment:
depends on species
P falciparum- quinine or artemisinin- side effects- hypoglyceamia
P vivax, ovale, malariae- chloroquine, hypnozoites (liver stage)
- doesnt work for falciparum as there is worldwide resistance
what preventative measures can be taken to prevent malaria infections?
A- assess risk- knowledge of risk areas- returning travellers
B- bite prevention- repellant, clothing, nets, chemopropholaxis before travel
C- chemoprophylaxis- specific to region, start before and continue after returning
what are the signs and symptoms of enteric fever (typhoid/ paratyphoid) and possible complications
systemic disease- bacteraemia
7-14 day incubation period
fever, headache, abdo pain, constipation, dry cough- normal CXR, bradycardia
complications- intestinal haemorrhage and perforation, 10% mortality if untreated
what investigations, treatments and preventions are used for enteric fever?
investigations- anaemia, lymphopenia, raised LFT- transaminase and bilirubin, Culture- blood and faeces, serology (antibody detection) not used anymore
treatment- resistance has led to treatment changing several times over the years- now ceftriaxone or azithromycin 7-14 days
preventions- food and water hygiene, typhoid vaccine- 75% protection, Vi capsular polysaccharide antigen
what other infections may salmonella bacteria cause and what symptoms do people get ?
food poisoning- s.typhimurium, s.enteritidis
diarrhoea, fever, vomiting, abdo pain
generally self limiting
what is dengue and what symptoms do people have?
arbovirus - transmitted through anthropods- mosquito
abrupt onset, severe myalgia, retro-orbital headache- first infection lasts 1-5days, improves 3-4 days after rash, supportive treatment only
- re infection with diff serotype- antibody dependent enhancement- dengue haemorrhagic fever (DIC), dengue shock syndrome- low BP, high HR
test with PCR or serology
