Travel Related Infection Flashcards by Jam E

Why are travelers more vulnerable to infection?

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.

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What are some infections that are common worldwide?

Influenza

Community acquired pneumonia

Meningococcal disease

Sexually transmitted disease

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

Sunburn
Heat exhaustion and heatstroke
Fungal infections
Bacterial skin infections
Cold injury
Altitude sickness

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Give examples of some ifnections controlled by public health measures

Sanitation:

Travellers diarrhoea
Typhoid
Cholera
Viral gastroenteritis

Immunization:

Poliomyelitis
Diptheria

Education:

HIV
STD’s

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What are some water related infections?

Schistosomiasis
Leptospirosis
Liver flukes
Strongyloidiasis
Hookworms
Guinea worms

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Give examples of arthropod - borne infections

Malaria (mosquitos)

Dengue fever (mosquitos)

Leishmaniasis (sand flies: kala-azar)

Filariasis (mosquitos: elephantiasis)

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What are some emerging infections?

Zika - latin america, caribbean

Ebola virus - west africa

Avian flu - china

West Nile virus - USA

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What is the main vector of malaria?

Female anopheles mosquito

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What species is the potentially severe form of malaria?

Plasmodium falciparum

Bengn includes:

Plasmodium vivax
Plasmodium ovale
Plasmodium malariae
Plasmodium knowlesi

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What are the clinical features of malaria?

Symptoms:

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

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What are the signs of malaria?

None

Splenomegaly

Hepatomegaly

Mild-jaundice

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What are the complications of malaria?

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)

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How is the diagnosis of malaria made?

•Thick & thin blood films

–Giemsa, Field’s stain

•Quantitative buffy coat (QBC)

–centrifugation, UV microscopy

•Rapid antigen tests

–OptiMal

–ParaSight-F

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

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What defines malaria as being complicated malaria?

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

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What are the treatment options for uncomplicated plasmodium falciparum?

Riamet - 3 days

Eurartesim - 3 days

Malarone - 3 days

Quinine (plus oral doxycycline or clindamycin) - 7 days

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

IV artesunate (unlicensed in the UK)

IV quinine (plus oral doxycycline or clindamycin)

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

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

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What are malaria control programmes?

•Mosquito breeding sites

–Drainage of standing water

•Larvacides

–(Paris green), temphos, biological

•Mosquito killing sprays

–DDT, malathion, (dieldrin)

•Human behaviour

–Bed nets

–Mesh windows

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What are the causative organisms for typhoid?

Salmonella typhi

Salmonella paratyphi

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What are the clinical features of typhoid?

•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

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How is the diagnosis of typhoid fever made?

•Clinical

–not easy

–evolution of features

•Laboratory (Salmonella typhi, S. paratyphi)

–Culture blood, urine & stool

–Culture bone marrow

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What is the treatment for typhoid fever?

Oral azithromycin

IV ceftriaxone - if complicated or concerned regarding absorption

What is the commonest human arbovirus infection?

Dengue

What causes the transmission of dengue?

Aedes aegypti

What is the classical presentation of dengue fever?

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

What is the tourniquet test? What does it assess?

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

What is the clinical and laboratory diagnosis of dengue?

Clinical: ## Footnote –Thrombocytopenia –Leucopenia –Elevated transaminases –Positive tourniquet test Laboratory - PCR, serology

What are the therapeutic agents for dengue fever?

No specific therapeutic agents

What are the complications for dengue?

–Dengue haemorrhagic fever (DHF) –Dengue shock syndrome (DSS) Rx: IV fluids, fresh frozen plasma, platelets

What are the prevention methods for dengue?

Avoid bites New vaccine (dengvaxia), 2016 limited use

What are the transmitting organisms for schistosomiasis?

Freshwater snails

What are the micro-organisms assocaited with schistosomiasis?

* S. haematobium * S. mansoni * S. japonicum

What is the schistosomiasis life cycle?

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

What are the clinical features of schistosomiasis?

•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

What is the diagnosis of schistosomiasis?

–Clinical diagnosis –Antibody tests –Ova in stools and urine - Rectal snip

What is the treatment for schistosomiasis?

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

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

Rickettsiosis R. Conorii

What are the clinical features of rickettsiosis?

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

What is the diagnosis of rickettsiosis?

Clinical features Serology

What is the management of rickettsiosis?

Tetracycline

Give examples of viral haemorrhagic fevers

Ebola CCHV - crimean congo haemorrhagic fever Lassa fever Marburg disease

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

High security infection unit Treatment is supportive

What virus causes Zika?

Flavivirus

What transmits the zika virus?

Daytime - biting aedes mosquitos Also by sexual contact, blood transfusion •Related to dengue, yellow fever, Jap B encephalitis and West Nile viruses

What geographical areas were associated with outbreaks of zika virus?

Pacific outbreak - 2013-2014 Latin america pandemic 2015 - 2016

What are the clinical features of zika virus?

•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

What are the control measures for Zika?

* No antiviral therapy * Mosquito control measures * Vaccines in development

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

Malaria

What travel disease might a rash be a sign of?

typhoid, typhus, dengue

What might jaundice be a sign of?

Hepatitis Malaria Yellow fever

What might lymphadenopathy be a sign of?

leishmania, trypanosomiasis

What might enlarged liver be a sign of?

malaria, typhoid, amoebic abscess

What might splenomegaly be a sign of?

•visceral leishmaniasis, typhoid, malaria

Investigations

* FBC * malaria films * liver function tests * stool microscopy & culture * urine analysis & culture * blood culture(s) * CXR

Specific tests as indicated

–dengue –respiratory viral/atypical –hepatitis A, B, C –tick typhus (Rickettsia) –schistosomiasis –amoebic –leptospirosis/hantavirus –viral haemorrhagic fevers

Treatment

* 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