Systemic Fungal Infections in Small Animals

1. Systemic Fungal Infections in Small Animals Colleen Hock May 12, 2010 http://atlas.arabslab.com/data/8/blasto10.gif

2. The Mycotic Agents • Blastomyces dermatitidis • Histoplasma capsulatum • Coccidioides immitis • All are dimorphic (mold and yeast forms) • Cause primarily respiratory disease by evasion of the host immune response

3. Blastomycosis • Blastomyces dermatitidis • South east, south central, and upper midwest near river valleys and lakes • Moist and shaded areas with increased organic matter (soil and wood) http://www.familyvet.com/Dogs/Fungi.html

4. Dogs: Dyspnea Anorexia Depression Lameness Lymphadenopathy Skin Lesions +/- occular manifestations +/- Orchitis Cats: Dyspnea Nasal discharge Cough Lethargy Weight loss Blastomycosis: Clinical Signs **Pneumonia and weight loss are the most common presentations**

5. Blastomycosis http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/596603 http://www.njmoldinspection.com/vetmycology/vetblastomycosis.html Cutaneous blastomycosis: Dermatitis Occular blastomycosis: Panophthalmitis

6. Blastomycosis: Pathogenesis Inhale spores  Deposit in the alveoli  Acute Pulmonary Phase   Self-limiting control of asexual reproduction Asexual budding, not eliminated by the immune system OR the patient is immunocompromised   Lymphatic and Hematogenous Spread of spores Pyogranulomatous Inflammation within the lungs  Inflammation in skin, bones, LN’s, eyes, CNS, and/or reproductive tract

7. Blastomycosis: Diagnosis • History, Clinical signs, and Diagnostic findings • Definitive diagnosis must show the organismCytology: TTW, BAL, LN aspirates, fluid from the anterior chamber of the eye, draining tracts, prostatic fluid, and CSF • Never Culture Blastomyces because of danger to personnel http://www.pharmacy-and-drugs.com/illnessessimages/blastomycosis2.jpg

8. Blastomycosis: Diagnosis • Serology (AGID) is helpful if the organism cannot be definitively diagnosed.- Sensitivity and Specificity > 90% • Thoracic Radiographs indicated when respiratory signs present:- interstitial pattern- nodular interstitial pattern/diffuse miliary - tracheobronchial lymphadenopathy

9. Blastomycosis: Pyogranulomatous Inflammation http://www.vet.uga.edu/vpp/clerk/mordecai/index.php

10. Nodular Interstitial Pattern/Diffuse Milliary Pattern • Differentials • Lymphoma • Fungal pneumonia • Pneumoconiosis • Hematogenous bacterial pneumonia • Metastases from thyroid or mammary carcinoma www.vet.uga.edu/vpp/clerk/mordecai/figure1.jpg

11. Blastomycosis: Fungal Granuloma • Differentials • -Tumor metastases • -Fungal granuloma • Parasitic granuloma • Abscesses • Lymphoma • Malignant histiocytosis • Lymphoid granulomatosis • Cysts/Fluid filled bullae http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/596603

12. Fungal Osteomyelitis: Blastomyces dermatitidis http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm

13. Fungal Osteomyelitis vs. Bone Tumors   http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20341%20Lecture%207%20Musculoskeletal%20Part%201.ppt#362,49,Fungal Osteomyelitis http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/BoneTumorsinCatsandDogs/

14. Blastomycosis: Treatment • Amphotercin B- IV, nephrotoxic- Lipid soluble form that is less toxic • Iatroconazole- less toxic- oral administration- more expensive http://www.cvs.com/CVSApp/images/health/A1055050.JPG

15. Histoplasmosis • Histoplasma capsulatum • Found in soil near avian species (especially starlings) and bats • 3 forms in dogs: pulmonary, disseminated, and subclinical • Rare and progressive in cats http://www.familyvet.com/Dogs/Fungi.html

16. Dogs- coughing- dyspnea- anorexia- weight loss- depression- ascites- ulcerated oral and/or nasal mucosa- anemia- lymphadenopathy- thrombocytopenia- fever- diarrhea Cats- weight loss- lethargy- fever (fluctuant) Histoplasmosis: Clinical Signs http://www.fs.fed.us/r8/caribbean/wildlife-facts/2007/wildlife-facts_images_2007/2-brazilian_free-tailed_bat.jpg http://cat.uab.cat/Publications/2005/SEP05/starlings.jpg

17. Histoplasmosis: Pathogenesis Inhale or ingest microconidia or hyhae  Conversion to yeast within the host  Yeasts engulfed by macrophages and they replicate intracellularly   Clear infection Immune system is overwhelmed  Hematogenous and Lymphatic spread

18. Histoplasmosis: Diagnosis • Cytology: exudates, TTW, FNA (LN’s), and Bone Marrow • Histopathology • Serology • Blood smear http://www.google.ca/imgres?imgurl=http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ

19. Histoplasmosis: Diagnosis • Radiographs:- pulmonary interstitial pattern with miliary or nodular infiltrates- Abdomen: hepatomegaly, splenomegaly, and ascites- Gastogram: Barium highlights thickening of the intestinal wall and mucosa- Abdominal Ultrasound for gi thickening- Bone: osteolysis with periosteal proliferation • Endemic areas: may see patients with calcification in the thorax or abdomen secondary to persistence of the organism

20. Histoplasmosis http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ.jpg

21. Histoplasmosis http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51108.htm

22. Histoplasmosis http://www.vet.uga.edu/vpp/clerk/edison/index.php

23. Histoplasmosis: Fungal osteomyelitis http://cal.vet.upenn.edu/projects/saortho/chapter_37/37F8.jpg

24. Histoplasmosis: Treatment • Iatroconazole: lower toxicity http://www.my-online-pharmacy.net/i/products/sporanox.jpg

25. Coccidiomycosis • Coccidioides immitis • Soil in arid or semi-arid regions • Virulent reputation • Epidemics after rainy season followed by a drought http://www.familyvet.com/Dogs/Fungi.html

26. Dogs- dyspnea- anorexia- cough- weight loss- lameness- draining tracts- abscesses- lymphadenopathy- meningitis Signs can range from flu-like symptoms to severe pneumonia when pulmonary tissue involved Can see extensive damage to bones, joints, skin, and CNS when dissemination occurs Fatal when immunocompromised Coccidiomycosis: Clinical Signs

27. Coccidiomycosis: Pathogenesis Inhalation of infective arthroconidia  Deposition in the lung  Microenvironment induces endosporulation  Endospores released   Removed by mononuclear cells Immunocompromised patients   Extensive lung damage Dissemination  Subclinical or clearance of organisms

28. Coccidiomycosis: Diagnosis • Cytology: exudate, TTW, LN or bone biopsy • Wet mount with 10% KOH- endospores 2-5 um- spherules 10-100 um- mycelial form= dangerous • Serology • Radiographs: Thorax and bones

29. Coccidiomycosis: wet mount http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm

30. Coccidiomycosis http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm

31. Coccidiomycosis: Fungal osteomyelitis http://www.familyvet.com/Dogs/Fungi.html

32. Coccidiomycosis: fungal osteomyelitis http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm

33. Coccidiomycosis: Treatment • Ketoconazole: helps to prevent dissemination • Iatroconazole www.amercianvetonline.com

34. References • http://www.vet.uga.edu/vpp/clerk/mordecai/index.php • http://www.familyvet.com/Dogs/Fungi.html • http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm • http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/BoneTumorsinCatsandDogs/ • http://www.pharmacy-and-drugs.com/illnessessimages/blastomycosis2.jpg • http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/596603 • http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51108.htm • http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ.jpg • http://www.vet.uga.edu/vpp/clerk/edison/index.php • http://cal.vet.upenn.edu/projects/saortho/chapter_37/37F8.jpg • http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm • http://www.vet.uga.edu/vpp/clerk/edison/index • Songer, J.G., & Post, K.W. (2003). Veterinary Microbiology. St Louis: Elsevier. • http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/BoneTumorsinCatsandDogs/ • http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20341%20Lecture%207%20Musculoskeletal%20Part%201.ppt#362,49,Fungal Osteomyelitis