Introduction

• The yeast Malassezia pachydermatis is a commensal and opportunistic pathogen of canine skin. It is a common cause of ceruminous otitis externa and seborrheic dermatitis in dogs. Resistance to Malassezia spp appears to be increasing. While antifungal agents still play a key role in managing M pachydermatis, other agents, such as chlorhexidine, are being employed increasingly to avoid selection of antifungal agent-resistant isolates. 
• Few species of fungus cause infection. Infection can be acquired by inhalation, ingestion, or through the skin (for example, through a cut or wound), most commonly from soil. Some fungi can cause local or generalized infection in otherwise healthy, immunocompetent individuals. Local or generalized infection with other fungi is more common in stressed or immunocompromised individuals (eg poor nutrition, viral infections, immunosuppressive drug therapy, prolonged antibiotic therapy). Antifungal agents play a key role in managing fungal infections in dogs. 
• Protozoan parasites, including vector-borne infections (eg Leishmaniosis) and intestinal protozoa (eg Giardia, Coccidiosis), are responsible for a number of different diseases in dogs. Some of these diseases have a worldwide distribution and others are of regional importance. Some are zoonotic (eg Leishmaniosis) making disease prevention in dogs key to protecting human health. Canine vector-borne disease can be prevented by consistent use of insecticides and acaricides as part of limiting exposure to ticks and other arthropod vectors and vaccination (eg for Leishmaniosis). Accurate, prompt diagnosis and appropriate, appropriate management measures (eg hygiene) and specific treatment and are critical to managing protozoan parasitic diseases in dogs.  

Yeast and fungal infections

Antifungal agents

Protozoal infections

Antiprotozoal agents

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Johnston L, Mackay B, King T, Krockenberger M B, Malik R, Tebb A (2021) Abdominal cryptococcosis in dogs and cats: 38 cases (2000-2018). JSAP 62, 19-27 PubMed.
• Bond R, Morris D O, Guillot J, Bensignor E J, Robson D, Mason K V, Kano R, Hill P B (2020) Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats - Clinical consensus guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 31, 28-74 PubMed. 
• Cohn L A (2020) Canine nasal disease: An update. Vet Clin North Am Small Anim Pract 50, 359-374 PubMed. 
• Guillot J, Bond R (2020) Malassezia yeasts in veterinary dermatology: An updated overview. Front Cell Infect Microbiol 10, 79 PubMed. 
• Penzhorn B L (2020) Don't let sleeping dogs lie: unravelling the identity and taxonomy of Babesia canis, Babesia rossi and Babesia vogeli. Parasit Vectors 13, 184 PubMed. 
• Davidson A P, Shubitz L F, Alcott C J, Sykes J E (2019) Selected clinical features of coccidioidomycosis in dogs. Med Mycol 57 (Supplement 1), S67-S75 PubMed. 
• Elad D (2019) Disseminated canine mold infections. Vet J 243, 82-90 PubMed. 
• Uiterwijk M, Nijsse R, Kooyman F N J, Wagenaar JA, Mughini-Gras L, Ploeger H W (2019) Host factors associated with Giardia duodenalis infection in dogs across multiple diagnostic tests. Parasit Vectors 12, 556 PubMed.
• Baneth G (2018) Antiprotozoal treatment of canine babesiosis. Vet Parasitol 254, 58-63 PubMed. 
• Elad D (2018) Therapy of non-dermatophytic mycoses in animals. J Fungi (Basel) 4, 120 PubMed.  
• Viana P G, Figueiredo A B F, Gremião I D F, de Miranda L H M, da Silva Antonio I M, Boechat J S, de Sá Machado A C, de Oliveira M M E, Pereira S A (2018) Successful treatment of canine sporotrichosis with terbinafine: case reports and literature review. Mycopathologia 183, 471-478 PubMed. 
• McAtee B B, Cummings K J, Cook A K, Lidbury J A, Heseltine J C, Willard M D (2017) Opportunistic invasive cutaneous fungal infections associated with administration of cyclosporine to dogs with immune‐mediated disease. J Vet Intern Med 31, 1724-1729 PubMed. 
• Moriello K A, Coyner K, Paterson S, Mignon B (2017) Diagnosis and treatment of dermatophytosis in dogs and cats.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol 28, 266-e68 PubMed. 
• Nevile J C, Hurn S D, Turner A G (2016) Keratomycosis in five dogs. Vet Ophthalmol 19, 432-438 PubMed.
• Solano-Gallego L, Sainz Á, Roura X, Estrada-Peña A, Miró G (2016) A review of canine babesiosis: the European perspective. Parasit Vectors 9, 336 PubMed. 
• Beugnet F, Moreau Y (2015) Babesiosis. Rev Sci Tech 34, 627-39 PubMed. 
• Chomel B B (2014) Emerging and re-emerging zoonoses of dogs and cats. Animals (Basel) 4, 434-445 PubMed. 
• Mendelsohn C, Rosenkrantz W (2014) Otitis externa series, part 2: topical therapy for otitis externa. Today’s Veterinary Practice November/December, 24-29 Full article.
• Sharman M J, Mansfield C S (2012) Sinonasal aspergillosis in dogs: a review. JSAP 53, 434-444 PubMed. 
• Little S E, DeBess E (2013) Parasite protocols for your practice - Canine protozoa. Today’s Veterinary Practice September/October, 43-47 Article. 
• Hummel J, Grooters A, Davidson G, Jennings S, Nicklas J, Birkenheuer A (2011) Successful management of gastrointestinal pythiosis in a dog using itraconazole, terbinafine, and mefenoxam. Med Mycol 49, 539-542 PubMed.
• Lester S J, Malik R, Bartlett K H, Duncan C G (2011) Cryptococcosis: update and emergence of Cryptococcus gattii. Vet Clin Pathol 40, 4-17 PubMed. 
• Lin Blache J, Ryan K, Arceneaux K (2011) Histoplasmosis. Compend Contin Educ Vet 33, E1-10; quiz E11 PubMed. 
• Werner A, Norton F (2011) Blastomycosis. Compend Contin Educ Vet 33, E1-4 PubMed.
• Gaastra W, Lipman  LJ, De Cock A W, Exel T K, Pegge R B, Scheurwater J, Vilela R, Mendoza L (2010) Pythium insidiosum: an overview. Vet Microbiol 146, 1-16 PubMed. 
• Stenner V J, Mackay B, King T, Barrs V R, Irwin P, Abraham L, Swift N, Langer N, Bernays M, Hampson E, Martin P, Krockenberger M B, Bosward K, Latter M, Malik R (2007) Protothecosis in 17 Australian dogs and a review of the canine literature. Med Mycol 45, 249-266 PubMed. 
• Brömel C, Sykes J E (2005) Histoplasmosis in dogs and cats. Clin Tech Small Anim Pract 20, 227-232 PubMed.
• Brömel C, Sykes J E (2005) Epidemiology, diagnosis, and treatment of blastomycosis in dogs and cats. Clin Tech Small Anim Pract 20, 233-239 PubMed. 

Other sources of information

• McAllister M M (2020) Neosporosis in animals. In: MSD Veterinary Manual. https://www.msdvetmanual.com/generalized-conditions/neosporosis/neosporosis-in-animals 
• Morrielo K A (2020) Dermatophytosis in dogs and cats. In: MSD Veterinary Manual. https://www.msdvetmanual.com/integumentary-system/dermatophytosis/dermatophytosis-in-dogs-and-cats 
• Petersen C (2020) Leishmaniosis in dogs. In: MSD Veterinary Manual. https://www.msdvetmanual.com/generalized-conditions/leishmaniosis/leishmaniosis-in-dogs 
• ESCCAP (2019) Control of vector-borne diseases in dogs and cats. ESCCAP Guideline 05 Third Edition - March 2019. https://www.esccap.org/uploads/docs/t2kkcbgl_0775_ESCCAP_Guideline_GL5_v9_1p.pdf 
• Taboada J (2018) Overview of fungal infections (Mycoses). In: MSD Veterinary Manual. https://www.msdvetmanual.com/generalized-conditions/fungal-infections/overview-of-fungal-infections 
• Koch S (2017) The challenge of chronic otitis in dogs: from diagnosis to treatment. Today’s Veterinary Practice Full article. 
• Booth D M (2015) Polyene macrolide antibiotics. In: MSD Veterinary Manual. https://www.msdvetmanual.com/pharmacology/antifungal-agents/polyene-macrolide-antibiotics 
• Constable P D (2015) Coccidiosis of cats and dogs. In: MSD Veterinary Manual. https://www.msdvetmanual.com/digestive-system/coccidiosis/coccidiosis-of-cats-and-dogs 
• Shipstone M (2014) Antifungals for Integumentary Disease. https://www.msdvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-integumentary-system/antifungals-for-integumentary-disease 
• Patton S (2013) Overview of giardiasis. In: MSD Veterinary Manual. https://www.msdvetmanual.com/digestive-system/giardiasis-giardia/overview-of-giardiasis