1. ACHA 2009 Name That Bug

2. Malaria-A Major World Disease 300-500 million cases annually 2.7 million deaths annually About 1500 US cases annually Prevalence increasing –Rising resistance –Anopheles vector spreading –Climate change –Increasing travel

4. Malaria A major cause of fever in the returning traveler A complicated disease –But resources are available

5. Fever in the Returning Traveler The Geosentinel Study –Malaria is #1 –Then Dengue –Mononucleosis –Rickettsial infection –Enteric fever (Typhoid or paratyphoid fever)

6. Malaria Etiology Caused by Plasmodium, a parasite Four important species –P. falciparum –P. vivax –P. ovale –P. malariae

7. The four species are not the same Falciparum –Often severe –High parasite burden –Organ damage common Non-falciparum –Generally not severe –Low parasite burden –Rare end organ damage

8. Malaria Transmission Predominantly due to the bite of a female Anopheles mosquito In US, there is rare transfusion spread –Also some “airport” infection

10. Malaria Pathogenesis The parasite digests red blood cell proteins, hemoglobin and deform the cell membrane Hemolysis occurs –Cytokines released Diseased cells filtered out by spleen and liver –Results in sequestration and enlargement

13. Malaria Signs and Symptoms FeverSweatsChillsHeadacheMyalgiasFatigue Abdominal pain

14. Malaria Diagnosis Light microscopy –Look at blood with Giemsa stain (or Wright’s stain) Look for ring forms in red cells, measure percent of red cells infected, look for “banana” forms

17. This is not vivax

18. CDC Assistance Call 770 488 7788 during normal business hours Call 770 488 7100 for emergencies

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20. The Salmonellae Motile gram negative bacilli Some cause gastroenteritis Some cause enteric fever Some cause bacteremia or endovascular infection Some cause osteomyelitis or abscess Some cause asymptomatic carrier state

23. This case was an example of enteric fever This case was an example of enteric fever Typhoid –Salmonella typhi –Salmonella paratyphi –Both are highly specific for human, not animal, infection –Always means that there was contact with an infected individual, a chronic carrier or contaminated food or water –21.6 million cases worldwide in one year, with 216,000 deaths

24. Typhoid in the USA Between 1994-1999 there were 1393 cases –30% had traveled to India –Strongly consider the typhoid vaccine

26. The Clinical Picture of Typhoid A febrile illness –Occurs 5-21 days after ingestion of the bacteria –Fever builds, is often sustained –May have abdominal pain, rose spots, liver or spleen enlargement –If untreated, has 15% mortality –Other symptoms may include headache, cough, relative bradycardia

28. The Diagnosis Established by blood culture

29. Sensitivity to Antibiotics Cipro often considered first choice But beware: resistance is growing –Lab testing may miss Cipro resistance, so specifically ask about sensitivity to nalidixic acid

31. Cipro

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33. Tuberculosis Tuberculosis Koch’s disease Received the Nobel prize for establishing that TB was caused by Mycobacteria tuberculosis in 1882

34. Tuberculosis A disease of antiquity –Mummies have had TB A disease of poverty A large fraction of cases in US are imported An indolent infection A disease of the “artiste” –For example the opera La Boheme

35. TB Epidemiology 14.6 million cases of active TB worldwide each year –1.6 million deaths per year 25,000 new US cases per year –About 50% are in foreign born

38. TB Presentation Symptoms are insidious Fever present in 50% Cough, weight loss or fatigue present in 66% X-ray often shows upper lobe infiltrate

41. A Critical Lab Test for Suspected Active Disease Collect multiple sputum specimens for “AFB smear and culture with sensitivity” –New tests are emerging to aid in diagnosis

43. TB Transmission and Prevention Generally by inhalation of droplet particles –One sneeze can create 40,000 droplets Screening high prevalence populations is helpful

44. TB Screening Focus is to detect both active disease and latent disease ACHA has guidelines Traditional test for latent TB is the Tuberculin skin test Newer tests utilize interferon assay –These tests are now recognized by CDC as equivalent to skin testing

45. TB Screening Tests Skin Testing –An acquired skill –Requires two visits –Well established Much data on sensitivity Cost stable –BCG may cause false positive Interferon Tests –Only needs phlebotomy skills and lab –One visit for result –Cost high, but coming down –Not prone to BCG influence Less data on sensitivity

46. TB Treatment Needs multiple effective drugs for long period of time ATS has established guidelines

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48. Fish Tapeworm Infection Diphyllobothrium Latum, the broad tapeworm Endemic wherever raw or undercooked fish is ingested Full grown worm lives in the human intestine, may reach 40 feet in length, may cause vitamin B12 deficiency with megaloblastic anemia

52. The Worm Itself A sucker head –Adheres to jejunum A neck A body –May consist of 4000 segments called proglottids The proglottids are hermaphroditic, produce up to a million eggs daily

57. American “outbreaks” Due to increased popularity of sushi from raw, unfrozen salmon –Especially farm raised

58. Tapeworm Symptoms Often asymptomatic When symptoms are present they are often vague –Diarrhea, cramping, fatigue –Occasional patient feels the worm segment hanging outside the anus or sees a partial segment in the toilet bowl

59. If complicated by B12 deficiency The patient may have anemia symptoms The patient may have anemia symptoms –Pallor, breathlessness Plus glossitis Plus findings of posterior column spinal cord disease –Loss of vibratory sense, proprioreception, poor coordination

60. Diagnosis Look in the stool for eggs, or sometimes segments of adult worms

63. Treatment Praziquantel is the drug of choice It kills the adult worm, so it will come out in the stool (warn patient) Low toxicity Dose is 5-10 mg/Kg as a single dose

65. Thank You!