Jared Bullard MD FRCPC Paediatric Infectious Diseases & Medical Microbiology Manitoba 10 th Annual Travel Health Conference Winnipeg, MB April 27,

Transcription

1 Jared Bullard MD FRCPC Paediatric Infectious Diseases & Medical Microbiology Manitoba 10 th Annual Travel Health Conference Winnipeg, MB April 27, 2012

2 No conflicts of interest to declare

3 1. Review basic pathophysiology of infectious agents causing diarrheal illness 2. Discuss common etiological agents of waterborne infections: a. Bacterial b. Parasites c. Viral 3. Use case illustrations to review the pertinent clinical details of waterborne travel infections

4 1. Chase children 2. Bath and feed children 3. Read MSc papers about lymphoma 4. Associate Medical Director at Cadham Provincial Laboratory 5. Pediatric Infectious Diseases consultant 6. Eat 7. Chase children 8. Sleep?

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7 500,000 deaths by drowning worldwide every year 4000 in the US per year Risk factors associated with drowning: Overestimation or inability to swim Risk taking behaviour Use of alcohol or illicit drugs Inadequate adult supervision Underlying seizure disorder or arrhythmia Hyperventilation pre-swim From Chandy and Weinhouse, 2012, uptodate.com

8 Dehli Belly Montezuma s Revenge Tunisia Two Step Pharaoh s Curse Over 4 billion cases of human diarrhea 1 : 1.6 million deaths 62.5 million disability adjusted life years (DALY) 1. Baldursson and Karanis, Water Research, 2011.

9 Low risk (<10%): Northern Europe, Australia and New Zealand, the United States, Canada, Singapore, Japan Moderate risk (10-20%): Caribbean Islands, South Africa, and countries bordering the Mediterranean Sea including Israel High risk (>30%): Asia (with the exception of Singapore and Japan), Africa (outside of South Africa), South and Central America, and Mexico 1. Wanke. UpToDate.com 2012.

10 Modified from Baldursson and Karanis, Water Research, 2011.

11 Bowel wall: Lined with cells Proteins to remove and excrete different substances Surface area required for proper aborption In come the bugs! Direct invasion Multiply and coat Produce toxin

12 Direct invasion: Pathogen enters cells or tissues of bowel wall Results in destruction and inflammation Loss of absorption Blood and inflammatory cells Smaller volume, scant stool with blood and mucous From infectionlandscapes.org

13 Bacteria: Salmonella Shigella Campylobacter Enteroinvasive E. coli (EIEC) Parasites: Entamoeba histolytica Balanditium coli Viruses*: Norovirus Rotavirus

14 From electricorchid.tumblr.com Multiply and coat: Enter bowel, do not penetrate bowel wall Multiply to large numbers Physically block absorption by bowel wall Diarrhea secondary to osmotic gradient Often moderate-large volume, non-bloody

15 Bacteria: Enteropathgenic E. coli (EPEC) Parasite: Giardia lamblia

16 Toxin-mediated: Bind to receptors on bowel wall Result in excretion of electrolytes Often large volume, watery stools Potential to go systemic From sharinginhealth.ca

17 Bacteria: Vibrio cholera Enterotoxigenic E. coli (ETEC) Enterohemmorhagic E. coli (EHEC) Clostridium difficile

18 The most common cause of traveller s diarrhea 1 Attributable to ETEC Role of Dukoral 2 : Whole cell, killed with B toxin subunit of cholera 2 doses separated by 1 week; 3 months of protection Reduction in incidence of traveller s diarrhea by 52-67% May decrease <7% of traveller s diarrhea cases Vaccination by patch? 1. Cabral. Int. J. Environ. Res. Public Health Wanke. UpToDate.com 2012.

19 Salmonella typhi exclusively a human pathogen Other Salmonella more animal-associated Cause typhoidal (S. typhi and S. paratyphi) and gastroenteritis disease Two vaccines for S. typhi typhoid fever: Live oral vaccine Ty21a (Vivotif) Vi polysaccharide vaccine (Typhim Vi) Efficacy between 50-80% Boost every 2 years (Typhim Vi) or 5 years (Vivotif) depending on risk of re-exposure Vi polysaccharide conjugated to non-toxic P. aeruginosa exotoxin A evaluated and promising 1 1. Hohmann, UpToDate.com 2012.

20 Protozoan parasite Cause 280 million diarrheal cases/year worldwide 1 Cysts and trophozoites Found in some animal hosts (beavers) Traditionally diagnosed by microscopy More sensitive stool antigen kits increasingly available 1. Baldursson and Karanis. Wat. Res

21 Treated with tinidazole, metronidazole and nitazoxanide Avoided by boiling, chemically disinfecting or filtering water

22 Highly infectious and difficult to disinfect As few as 10 particles can cause infection Standard disinfectants ineffective; requires 1:50 solution of household bleach 30% may be asymptomatic and shedding Spread by water but also vomitus and can be concentrated in shellfish No specific therapy Hand hygiene!

23 Increasing symptoms as you age: Fever, jaundice, malaise, anorexia Only 30% of children < 6 years Sx versus 70% of children and adults > 6 years No chronic infection and rare fulminant hepatitis Primarily person-to-person transmission Transmission by water via fecal-oral route

24 Prevented by: Vaccination (Havrix, Twinrix) highly efficacious (95% one dose; 99% two doses) Duration of protection ~20-25 years Immunoprophylaxis Immune globulin for < 1 year and >41 years

25 Poor water and sewage systems Kitchen staff often inadequate training in food hygiene Resulting higher risk of food and waterborne gastroenteritis 1. Cartwright. J. App. Micro

26 Introduction of improved sanitation in 1990s Impact on incidence of diarrheal disease on cruise ships: 29.2 per 100,000 passenger days in per 100,000 passenger days in Cramer et al. Am. J. Prev. Med

27 Norovirus (NoV) a common cause of diarrhea at sea Incidence of NoV not impacted by improved sanitation Likely due to fomites Overall risk of gastroenteritis on ship ~1% for 7 day cruise 1. Cramer et al. Am. J. Prev. Med

28 Diarrhea via waterborne pathogens is common Can be prevented by: Selecting safer beverages (like beer) Careful hand hygiene Filtering, chemically treating or boiling water prior to consumption Carrying a supply of antibiotics (azithromycin or fluoroquinolone) not a bad idea Vaccines are available; balance risk, costs and benefits

29 Water also harbours organisms that can gain access via your skin Sometimes want to cause an infection right there Others just get lost Some are more interested in other places

30 Different bacteria cause SSTI from both fresh and salt water Useful acronym to remember them, AEEVM: Aeromonas spp. Edwardsiella spp. Erysipelothrix spp. Vibrio vulnificus Mycobacterium marinum Often introduced via trauma in marine environment

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36 Approximately 200 million people infected; 200,000 deaths/year from schistosomiasis 1 Caused by 3 main species: Schistosoma mansoni Carribean, South America, Middle East, sub-saharan Africa Schistosoma haematobium North and sub-saharan Africa, Middle East, Turkey and India Schistosoma japonicum China, The Phillipines, Thailand, Indonesia and other parts of Asia Leder and Weller, UpToDate.com, 2012

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38 Schistosomal/cercarial dermatitis or Swimmer s itch Commonly seen in North America caused by avian Schistosome spp. Can also be seen with Schistosoma japonicum Initially itchy followed by intensely pruritic papules May last up to a week or more Sensitization possible

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40 A 35 year old man goes to India to visit friends and relatives He does not seek pre-travel advice 1 week after returning to Canada, he develops fever, chills, headache and myalgias He had noted a diarrheal illness approximately 2 weeks ago His examination is significant for a T 39.9 C, HR 60 and diffuse abdominal pain

41 What is the most likely diagnosis? Is treatment warranted? How could this infection have been prevented?

42 A 50 year old woman and her 53 year old husband visit Galveston, Texas They enjoy an evening of raw oysters, wine and conversation 2 days later they are both suffering from profuse watery diarrhea

43 What is the most likely pathophysiology behind this presentation? What pathogen do you expect has boarded them? If vomiting was a feature of their illness, what do you now think is most likely causing their disease?

44 A 19 year old woman is taking her summer vacation by travelling in South America She did seek pre-travel advice and is following it! Following a day excursion to the jungle including swimming in a secluded waterfall she returns to the village 2 weeks later she has significant fever, chills, myalgias, headache and bone pain

45 What pathogen is likely causing her disease? What test could you perform to confirm your suspicion?

46 Following a trip to Mexico, a 24 year old male develops mild fever and diarrhea Blood and mucous are noted in the stool He presents to medical attention and a stool sample is sent This organism is discovered

47 What type of pathogen is this? What treatment would be useful?

48 1. Review basic pathophysiology of infectious agents causing diarrheal illness 2. Discuss common etiological agents of waterborne infections: a. Bacterial b. Parasites c. Viral 3. Use case illustrations to review the pertinent clinical details of waterborne travel infections

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