Τravel Related Infections Flashcards
What do you need to find out about the place?
Specific location When they went How they got there Stop anywhere en route? Accommodation type Were preventative measures taken eg vaccines?
What is it important to find out about if a patient has been travelling
Where they went
How long for
Time of year they went (so when)
What they did there
What can you find out about the person?
Did they take any preventative measures?
Why is it important to find out about the pathogen?
Can get different strains in different places which are antigenically different.
Impacts on protection and detection
Can get different antibiotic resistance depending on which antibiotics are regularly used in that country
Why is it important to identify if the infection is travel related?
Patient may need to be isolated
Labs should be alerted to potential hazards
What are the four species of malaria?
Plasmodium falciparum
Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
What is the vector of malaria?
Female Anopheles mosquito
Where is malaria common?
Tropics of Africa
Asia
Middle East
South and Central America
What is the incubation period of malaria?
1-3 weeks
History of malaria?
Fever chills and sweats every 3rd/4th day Malaise Headache Cough Fatigue Arthralgia
What investigations should be done for malaria?
LFTs U&Es Head CT if there are CNS symptoms Glucose Blood smear to detect parasites FBC
Treatment of malaria?
P. falciparum (malignant) - quinine/artemisinin
P. vivax, ovale, malariae (benign) - chloroquine, primaquine
How does malaria get to humans?
Mosquito carries the parasite in its salivary gland and gut
Bites the human
What are the two cycles of malaria?
Liver - exo-erythrocytic
Blood - erythrocytic
How can malaria be prevented
Assess risk - knowledge of risk areas
Bite prevention - repellant, clothing, nets, chemoprophylaxis
Chemoprophylaxis - specific to region, start before and continue after return
Reasons why patients don’t take malarial prophylaxis properly?
Don’t know or think they need to take it
Don’t take it for the required period
What is entered fever?
Typhoid paratyphoid
Caused by salmonella
Where is enteric fever common?
Asia
Africa
South America
How is enteric fever spread?
Fecal-oral route from food and water
Due to poor sanitation
The only source is another infected human only
What causes enteric fever?
salmonella
Subspecies is enterica
Part of the Enterobacteriacea genus/family?
Features of salmonella?
Anaerobe
Gram negative bacilli
Does not ferment lactose
How does salmonella cause disease?
Produces Gram negative endotoxin
Invasin allows intracellular growth
Fimbriae adhere to epithelium over ileal lymphoid tissue (Peyer’s patches) where they multiply
Gain entry into the reticuloendothelial system
Symptoms and signs of enteric fever?
Systemic disease with fever and headache Abdominal discomfort Constipation Dry cough Hepatosplenomegaly Rash on abdomen (rare) Bradycardia
Incubation period of enteric fever?
7-14 days
Complications of enteric fever?
Intestinal haemorrhage
Perforation around Peyer’s patches
Investigations for enteric fever?
Moderate anaemia
Lymphopenia (low lymphocytes)
Raised LFTs (transaminase and bilirubin)
Blood and faeces cultures
Treatment of enteric fever?
Ceftriaxone or azithromycin
Prevention of enteric fever?
Food and water hygiene
Vaccine for high risk travel and lab personnel
What can non-typhoidal salmonella infections be caused by?
Salmonella typhimurium and enteritidis
Symptoms of non-typhoidal salmonella infections?
Diarrhoea Fever Vomiting Abdominal pain (Food poisoning)
Complications of non-typhoidal salmonella infections?
Normally self-limiting
Bacteraemia
Deep-seated infection
What type of virus is influenza?
Enveloped
Negative
Single-stranded RNA
What are the three subtypes of influenza and what is the subtype defined by?
A, B, C
Nucleoproteins
-haemagglutin
-neuraminidase
What is antigenic drift?
Mutations within the genes that code for antibody binding sites
This is what changes the antigens annually
What is antigenic shift?
Process by which two or more strains of a virus combine to form a new antigen having a mixture of the surface antigens of the two and of the original strains
Is it A or N which normally undergoes antigenic shift?
A
Does antigenic shift or drift lead to pandemics?
Shift
Incubation period of influenza?
1-4 days
Signs and symptoms of influenza?
Headache
Myalgia
Fever
Cough
When is influenza infectious?
The day preceding and first 3 days of symptoms
Complications of influenza?
Primary viral pneumonia
Secondary bacterial pneumonia
Characteristics of Legionella pneumophilia?
Fastidious
Gram negative
Pleomorphic
Where is Legionella pneumophilia found?
Water between 20 and 40*C
How is Legionella pneumophilia spread?
When aerosols are generated eg showers and AC systems
What is Legionella pneumophilia associated with?
Previous lung disease
Smoking
High alcohol intake
Immunocompromised patients in hospital are vulnerable if AC is not adequately maintained
Clinical features of Legionella pneumophilia
Mild, flu like illness sometimes
Other times - pneumonia with severe respiratory failure and high mortality
Can have GI symptoms before lung symptoms
Unproductive cough
Progressive dyspnoea
Confusion
How is Legionella pneumophilia diagnosed?
Sputum/bronchoalveolar lavage fluid cultured
Colonies identified serologically
Treatment of Legionella pneumophilia
Macrolide
Rifampicin
What type of bacteria is the one that causes Brucellosis?
Gram negative
Coccobacillus
How is the brucellosis pathogen (Brucella melitensis, abortus, suis) transmitted?
Direct contact with animals or their products though skin breaks/ingestion
abortus - cattle
suis - pigs
melitensis - goats
How does Brucella cause disease?
Lives in cells of the reticulo-endothelial system
Uses superoxide dismutase and nucleotide-like substances to inhibit intracellular killing mechanisms of host
Symptoms of Brucellosis?
High fever Myalgia Arthralgia Lumbosacral tenderness Epidydimitis
How is brucellosis diagnosed?
Blood cultures
How is brucellosis treated?
Doxycycline
Rifampicin
