Travel Related Infections Flashcards
What is vulnerability of travelers to infection impacted by?
- Temptation to take risks away from home
- food, water, animals, sex
- Different epidemiology of some diseases
- HIV, TB, polio, diphtheria
- Incomplete understanding of health hazards
- Stress of travel
- Refugees: deprivation, malnutrition, disease, injury
What are some common infections worldwide?
- influenza
- community-acquired pneumonia
- meningococcal disease
- sexually transmitted diseases
What are some climate or environmental health problems?
- Sunburn
- Heat exhaustion and heatstroke
- Fungal infections
- Bacterial skin infections
- Cold injury
- Altitude sickness
What are some public health measures to control infection?
-
Sanitation
- Travelers’ diarrhoea
- Typhoid
- Hepatitis A or E
- Giardiasis
- Amoebiasis
- Helminth infections
- Viral gastroenteritis
- Food poisoning
- Shigella dysentery
- Cholera
- Cryptosporidiosis
-
Immunization
- Poliomyelitis
- Diphtheria
-
Education
- HIV
- STD’s
What are some water related infections?
- Schistosomiasis
- Leptospirosis
- Liver flukes
- Strongyloidiasis
- Hookworms
- Guinea worms
What are some arthropod-borne infections?
- Malaria (mosquitos)
- Dengue fever (mosquitos)
- Rickettsial infections (ticks: typhus)
- Leishmaniasis (sand flies: Kala-azar)
- Trypanosomiasis (tsetse fly: sleeping sickness)
- Filariasis (mosquitoes: elephantiasis)
- Onchocerciasis (black flies: River Blindness)
What is the malaria vector?
Malaria vector is the female anopheles mosquito
Describe the malaria lifecycle?
1) Bite
2) Sporozoite released
3) Becomes merozoitres in liver
4) Infects red blood cells
What are the 5 species of malaira?
- Potentially severe
- Plasmodium falciparum
- Benign
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae
- Plasmodium knowlesi
What are the clinical features of malaria?
- Symptoms
- fever
- rigors
- aching bones
- abdo pain
- headache
- dysuria
- frequency
- sore throat
- cough
- Signs
- none
- splenomegaly
- hepatomegaly
- mild jaundice
What are some potential complications of malaria?
- Cerebral malaria (encephalopathy)
- Blackwater fever
- Pulmonary oedema
- Jaundice
- Severe anaemia
- Algid malaria
How is malaria diagnosed?
- Thick and thin blood films
- Quantitative buffy coat (QBC)
- Rapid antigen tests
How is severity of malaria measured?
Severity assessment, complicated malaria has one or more of:
- Impaired consciousness or seizures
- Hypoglycaemia
- Parasite count ³2%
- Haemoglobin £ 8mg/dL
- Spontaneous bleeding / DIC
- Haemoglobinuria
- Renal impairment or pH <7.3
- Pulmonary oedema or ARDS
- Shock (algid malaria)
- ?Gram negative bacteraemia
What is the 1st and 2nd line treatment of malaria?
- 1) Quinine
- 2) Artemisinins
What are the treatment options for malaria?
- Uncomplicated malaria
- Riamet (3 days)
- Eurartesim (3 days)
- Malarone (3 days)
- Quinine (7 days) plus oral doxycycline
- Complicated or severe P. Falciparum malaria
- IV artesunate (unlicensed in UK)
- IV quinine plus oral doxycycline
- Treatment of P. Vivax, P. Ovale, P. Malariae, P. Knowlesi
- Chloroquine 3 days
- Riamet 3 days
- Add primaquine 14 days in vivax and ovale to eradicate liver hyponozoites
What are some methods of controlling malaria?
- Mosquito breeding sites
- Drainage of standing water
- Larvacides
- (Paris green), temphos, biological
- Mosquito killing sprays
- DDT, malathion, (dieldrin)
- Human behaviour
- Bed nets
- Mesh windows
Typhoid fever is also known as what?
Enteric fever
Typhoid is caused by what organisms?
- Salmonella typhi
- Salmonella paratyphi
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
How is typhoid diagnosed?
- Clinical is not easy, done by evolution of features
- Laboratory
- Culture blood, urine and stool
- Culture bone marrow
What is the treatment of typhoid?
- Oral azithromycin
- If uncomplicated
- IV ceftriaxone
- If complicated or concerned regarding absorption
What is dengue caused by?
Dengue virus
What is the vector of dengue?
Mosquito borne (aedes aegypti)
What are the clinical features of dengue?
- Sudden fever
- Severe headache, retro-orbital pain
- Severe myalgia and arthralgia
- Macular/ maculopapular rash
- Haemorrhagic signs: petechiae, purpura, positive tourniquet test
How is dengue diagnosed?
- Clinical
- Thrombocytopenia
- Leucopenia
- Elevated transaminases
- Positive tourniquet test
- Laboratory
- PCR
- Serology
Describe the management of dengue?
- No specific therapeutic agents
- Complications
- Dengue haemorrhagic fever (DHF)
- Dengue shock syndrome (DSS)
- Rx: IV fluids, fresh frozen plasma, platelets
- Prevention
- Avoid bites
- New vaccine (Dengvaxia)
What is schistosomiasis also known as?
Snail fever
What is schistosomiasis caused by?
Parasite flatworms called schistosomes
What is the vector of schistosomiasis?
Freshwater snails
What are different species of schistosomes?
- S. haematobium
- S. mansoni
- S. japonicum
What are the different kinds of schistosomiasis?
Can be hepatic or urinary infection (or a mix)
Describe the lifecycle of schistosomiasis?
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
How is schistosomiasis diagnosed?
- Clinical diagnosis
- Antibody tests
- Ova in stools and urine
- Rectal snip
What is the treatment for schistosomiasis?
- Praziquantel
- 20mg/kg
- Prednisolone if severe
What organism caused tick thyphys?
Caused by rickettsiosis
What are some different illnesses caused by rickettsiosis?
- Tick typhus (R. conorii, R. africae)
- Rocky Mountain Spotted Fever (R. rickettsii)
- Epidemic typhus (R. prowazekii)
- Murine or endemic typhus (R. mooseri)
- Scrub typhus (R. tsutsugamushi)
- others
What are some clinical features of tick typhus?
- Abrupt onset of fever
- Headache
- Confusion
- Endovasculitis
- Rash
- Bleeding
How is tick typhus diagnosed?
- Clinical features
- Serology
Describe the management of tick typhus?
- Tetracycline
What are examples of viral haemorrhagic fevers?
These are serious infections but rare in UK:
- Ebola
- Congo-Crimea haemorrhagic fever
- Lassa fever
- Marburg disease
What is the treatment for viral haemorrhagic fevers?
Rule out common severe infections
Requires isolation in high security infection unit
Only treatment is supportive
What causes zika?
Flavivirus
What is the vector of zika?
Transmitted by daytime-biting aedes mosquitoes, or sexual contact or blood transfusion
What are clinical features of zika?
- No or mild symptoms
- Headache
- Rash
- Fever
- Malaise
- Conjunctivitis
- Joint pains
- In pregnancy can cause microcephaly and other neurological problems
What is the treatment of zika?
- No antiviral therapy
- Mosquito control measures
- Vaccines in development
What illnesses have specific tests available?
- dengue
- respiratory viral/atypical
- hepatitis A, B, C
- tick typhus (Rickettsia)
- schistosomiasis
- amoebic
- leptospirosis/hantavirus
- viral haemorrhagic fevers
