Travel Related Infection Flashcards
What are some infections controllable by sanitation measures?
Travellers diarrhoea, typhoid, hepatitis A and E, giardiasis, cholera, food poisoning and viral gastroenteritis
What are some infection controllable by immunisation?
Poliomyelitis and diphtheria
What are some water related infections?
Schistomiasis, Leptospirosis, liver flukes, hookworms, guinea worms and strongyloidiasis
What are some arthropod-borne infections?
Malaria, dengue fever, rickettsial infections, leishmaniasis, trypanosomiasis, filariasis and onchocerciasis
What are some important tropical diseases?
Malaria, typhoid, dengue fever, schistosomiasis, rickettsiosis, viral haemorrhage fevers and zika fever
What is the malaria vector?
Female anopheles mosquito
Describe the malaria life cycle
Mosquito takes blood meal and implants sporozoites which change to merozoites in liver
RBCs then carry the gametocyte which is picked up by mosquito
What are the 5 species of Malaria?
Plasmodium falciparum (potentially severe), vivax, ovale, malariae, and knowlesi
What are the symptoms of Malaria?
Fever, rigors, aching bones, abdomen pain, headache, dysuria, frequency, sore throat and cough
What are the signs of Malaria?
None
Splenomegaly, hepatomegaly and mild jaundice
What are some complications of Malaria?
Cerebral malaria - encephalopathy
Blackwater fever
Pulmonary oedema
Jaundice
Severe anaemia
Algid malaria
Describe blackwater fever
Severe intravascular haemolysis
High parasitaemia and profound anaemia
Haemoglobinuria
Acute renal failure
Describe cerebral malaria
Non invasive visitors and children in endemic areas
Get hypoglycaemia, convulsions and hypoxia due to reduced BF
How is malaria diagnosed?
Thick and thin blood films - Giemsa and field stain
Quantitative buffy coat - centrifugation and UV microscopy
Rapid antigen test - OptiMal and ParaSight-F
What does complicated malaria have one or more of?
Impaired consciousness or seizures, hypoglycaemia, parasite count more than 2%, haemoglobin less than 8mg/dl, spontaneous bleeding, haemoglobinuria, renal impairment, pulmonary oedema, and shock
What are the Malaria drugs?
Quinine from Chinchona
Artemisinins from Quinghaeosu
What are the treatment options for uncomplicated P. falciparum malaria?
Riamet 3 days
Eurartesim 3 days
Malarone 3 days
Quinine 7 days plus oral doxycycline
What are the treatment options for complicated or severe P. falciparum malaria?
IV quinine plus oral doxycycline
When patient is able to swallow and is stable then switch to oral treatment
IV artesunate - not in UK
What is the treatment for the other types of malaria?
Chloroquine 3 days
Riamet 3 days
Add primaquine in vivax and ovale to eradicate liver hypnozoites
What are malaria control programmes?
Mosquito breeding sites
Larvacides
Mosquito killing sprays
Human behaviour
Describe typhoid fever
Salmonella typhi and salmonella paratyphi
Widespread - poor sanitation and unclean drinking water
Incubation period - 7 days to 4 weeks
What are the clinical features of typhoid fever?
1st week - fever headache, abdomen pain, constipation, dry cough, bradycardia, neutrophilia and confusion
2nd - fever peaks, rose spots, diarrhoea, tachycardia and neutropenia
3rd - complications
4th - recovery
What are the complications of typhoid fever?
Intestinal bleeding, perforation, peritonism and metastatic infections
How is typhoid fever diagnosed?
Clinical - not easy
Lab - culture blood, urine and stool
Culture bone marrow
What is the treatment for typhoid fever?
Oral Azithromycin
IV Ceftriaxone
Describe Dengue
Swahili
Commonest human arbovirus infection
Infection - 100 million cases a year and 25000 deaths a year
How is Dengue transmitted?
Aedes aegypti - mosquito daytime biting near pools of water
What is the classical Dengue fever?
Sudden fever
Severe headache and retro-orbital pain
Severe myalgia and arthralgia
Macular rash
Haemorrhagic signs - petechiae, purpura and positive tourniquet test
What is the Dengue rash?
Muscular and petechial rash
How is Dengue diagnosed?
Clinical - thrombocytopenia, leukopenia, elevated transaminases and positive tourniquet test
Lab - PCR and serology
What is included in management of Dengue?
No specific therapeutic agents
Complications - IV fluids, fresh frozen plasma and platelets
Prevention - avoid bites and new vaccine
What are the complications of Dengue?
Dengue haemorrhagic fever
Dengue shock syndrome
How is Schistosomiasis transmitted?
Fresh water and freshwater snails
What are the types of schistosomiasis?
S. haematobium, mansoni and japonicum
Describe the Schistosomiasis life cycle
Eggs hatch releasing miracidia - penetrates snail tissue then sporocysts in snail
Penetrates skin - shistosomulae go into circulation and migrate to liver and mature
Paired adult worm migrates to bowel to lay eggs in stool
What are the clinical features of Schistosomiasis?
Swimmers itch - 1st few hrs
Invasive stage - cough, abdo discomfort, splenomegaly and eosinophilia
Katayama fever
Acute disease - eggs in bowel or bladder
Chronic disease
What is katayama fever?
Prostate, fever, urticaria, lymphadenopathy, splenomegaly, diarrhoea and eosinophilia
How is schistosomiasis diagnsoed?
Clinical
Antibody test
Ova in stool and urine
Rectal snip
What is the treatment for schistosomiasis?
Praziquantel
Prednisolone if severe
What are characteristics of tick typhus?
Tick bite eschar
Maculopapular rash
What is the main type of Rickettsiosis?
Tick typhus
