2. Pythium insidiosumPythium insidiosum
Kingdom StramenipilaKingdom Stramenipila
Oomycete “aquatic fungus”Oomycete “aquatic fungus”
Hyphal elements similar to FungiHyphal elements similar to Fungi
Primarily an infectious agent of plantsPrimarily an infectious agent of plants
PythiosisPythiosis
PhycomycosisPhycomycosis
Florida Horse LeechesFlorida Horse Leeches
Swamp CancerSwamp Cancer
3. Species Infected bySpecies Infected by Pythium insidiosumPythium insidiosum
CanineCanine Australia, Brazil, Korea, USA and VenezuelaAustralia, Brazil, Korea, USA and Venezuela
EquineEquine Australia, Brazil, Colombia, Costa Rica, New Zealand,Australia, Brazil, Colombia, Costa Rica, New Zealand,
New Guinea, USA and VenezuelaNew Guinea, USA and Venezuela
FelineFeline USAUSA
BovineBovine Brazil, USA and VenezuelaBrazil, USA and Venezuela
HumanHuman Australia, New Zealand, Haiti, India ThailandAustralia, New Zealand, Haiti, India Thailand
and the USAand the USA
BearBear USAUSA
CamelCamel USAUSA
4. Incidence of Pythiosis in the USIncidence of Pythiosis in the US
1995-2003 158 cases (all species)
2004 72 cases (all species)
2005 (Jan-Aug) 102 cases (all species)
2010 752 cases (all species)
17. Laboratory Diagnosis
1) Very few laboratories are familiar with
P. Insidiosum
2) Difficult to culture
3) Difficult to identify in histopath studies
4) Difficult to identify by clinical
presentation
22. What is Pythium Immunotherapy?
Allergy desensitization via Subcutaneous
presentation of purified P. insidiosum antigens
Switching of the of the immune response
from TH2 (allergic) to TH1 mode
(protective and curative)
25. Pythium antibody in Canines participating in FieldPythium antibody in Canines participating in Field
Trial Training and CompetitionsTrial Training and Competitions
Result #Dogs % of TotalResult #Dogs % of Total
Negative 105 61.4Negative 105 61.4
Borderline 43 25.1Borderline 43 25.1
PositivePositive 23 13.523 13.5
Total 171 100Total 171 100
* Normal Dogs <1 % Positive ,<5% Borderline, >95% Negative* Normal Dogs <1 % Positive ,<5% Borderline, >95% Negative
26. Pythium Associated Symptoms in Field Trial/HuntPythium Associated Symptoms in Field Trial/Hunt
CaninesCanines
VOMITING/DIARRHEAVOMITING/DIARRHEA
IN LAST 12 MONTHSIN LAST 12 MONTHS
Blood testBlood test
Negative 7 (6.7%)Negative 7 (6.7%)
Borderline 3 (7.0%)Borderline 3 (7.0%)
Positive 13 (26.1%)Positive 13 (26.1%)
32. Immunotherapy
♦ Purified protein extract of P. insidiosum
♦ Early treatment increases success rate
♦ Use as first option treatment
♦ >85% effective in equines, 50% effective in
canines
♦ Combine with surgical de bulking in chronic
cases
33. • Pythium insidiosum is endemic in
tropical and subtropical regions
• Differential diagnosis includes
subcutaneous mycosis, lymphoma,
parasitic and bacterial infections
• Serologic diagnosis is fast and accurate
• Itraconazole, Amphotericin B, Iodine and
surgery have shown limited success
• Immunotherapy alone or in conjunction with
other therapies demonstrates highest success
rate
34. Lagenidium gigantumLagenidium gigantum
Similar to Pythium in classSimilar to Pythium in class
Similar to Pythium in diseaseSimilar to Pythium in disease
characteristicscharacteristics
Essentially identical to Pythium inEssentially identical to Pythium in
tissue sectionstissue sections
Does not respond to PythiumDoes not respond to Pythium
ImmunotherapyImmunotherapy
35. Accurate Diagnosis is EssentialAccurate Diagnosis is Essential
Clinical presentation is not goodClinical presentation is not good
enoughenough
Histopath examination is not goodHistopath examination is not good
enoughenough
Pythium test alone is not good enoughPythium test alone is not good enough
Accurate diagnosis requires blood testAccurate diagnosis requires blood test
for both Pythium and Lagenidiumfor both Pythium and Lagenidium
Editor's Notes
Subcutaneous No draining tracts
Cutaneous Intestinal infection occurs in +/- 50% of infected dogs Peri-anal cutaneous lesions develop secondary to intestinal lesions
Usually cutaneous Up to 5% annual herd loss in herds studied in Venezuela
Results in 1-2 days vs 2-3 weeks for histopath Sensitivity >95% Specificity > 99% 1 cc serum required Cost $40 per sample
Surgery must be done in first 30 days of infection with complete removal of Pythium “ Wide and Deep” Equine Immunotherapy >90% at 30 days >75% at 60 days >60% at 90 days Canines probably similar, but most intestinal cases present at >90 days
Intense allergic/inflammatory response leading to tissue death and necrosis
Top Eosinophil/mast cell changing to Macropahge/lymphocyte Bottom Hyphae death and removal
Historical Equines overall 65-75% (90% in 30 day dropping to 50% in 90 day) (in this study 3 of 6 failures were >90 day infections) Canines overall 35% Lower due to advanced Intestinal infections
8/22/03 initial trmt 9/27/03 90 days 11/25/03 120 days 3/17/04 240 days
In advanced cases de-bulking has proven helpful. Removes a large part of the Pythium allowing immuno destruction of remaining inection.
