Also see Fungal Infections in Animals.
Fungal organisms rarely cause disease in healthy nonhuman primates, because most fungi are facultative pathogens that affect only very young or immunocompromised animals.
Microsporum spp and Trichophyton spp rarely infect institutional nonhuman primates. In clinical practice, these fungal agents are more common in privately owned monkeys. Topical treatment of ringworm with undecylenic acid ointment or 1% tolnaftate cream every 12 hours for 2–3 weeks can help, but nonhuman primates often lick off topical medications, making treatment ineffective.
The following drugs are effective against Microsporum and Trichophyton infections:
microsize griseofulvin: 20 mg/kg, PO, every 24 hours, long-term until the infection has cleared
itraconazole: 5–10 mg/kg, PO, every 24 hours, long-term until the infection has cleared
ketoconazole: 5–10 mg/kg, PO, every 12 hours for 30 days
fluconazole: 5 mg/kg, PO, every 24 hours for 30 days
Candida spp are common saprophytes of the skin, GI tract, and reproductive tract that act as facultative pathogens in debilitated nonhuman primates. Ulcers or white, raised plaques occur on the tongue or mouth. The fungus can also attack fingernails. Oral lesions caused by Candida must be differentiated from those caused by trauma, Mpox (previously called "monkeypox") infection, or herpesvirus infection via an accurate history combined with culture or cytological examination.
A cream containing nystatin (100,000–500,000 U/animal, topically, every 8–12 hours for 7 days) is effective in superficial Candida infections. Nystatin (200,000–300,000 U/kg, PO, every 6 hours for 48 hours after clinical recovery) is effective for candidiasis of the GI tract. Fluconazole (5 mg/kg, PO, every 24 hours for 15 days) has also been successful.
Dermatophilus congolensis infection has been reported in owl monkeys. Papillomatous lesions occur on the face and extremities. Diagnosis is typically based on results of cytological or histological evaluation or on culture and isolation. The infection is transmissible to humans. Regular bathing and husbandry enhancements can improve clinical signs in affected animals. Antifungal treatment should be based on culture and susceptibility testing.
Aspergillosis can develop in various nonhuman primate species. Aspergillus is usually a facultative pathogen in immunocompromised hosts, causing localized infections to disseminated infections, especially pulmonary infections with tracheobronchitis and cerebral infections with neurological signs. Treatment with voriconazole or terbinafine is empirical.
In endemic regions of the western and southwestern US, Coccidioides immitis has been associated with pneumonia and disseminated mycosis (“valley fever”) in monkeys and apes after exposure to airborne spores of this soil fungus. Serological testing is available for this agent, and a positive titer indicates likely infection.
Histoplasmosis, blastomycosis, and cryptococcosis have all occurred in nonhuman primates. Clinical signs include generalized lymphadenopathy, draining tracts in the skin, and respiratory signs with accompanying radiographic changes. Diagnosis can be based on cytological examination of fine-needle aspirates, biopsy, or positive results on a commercial lateral flow assay.
In the US, many fungal organisms are reportable on a state-by-state basis because of their zoonotic potential. Fluconazole (5 mg/kg, PO, every 24 hours for months to years) can be required to clear infection. A negative lateral flow assay result should be obtained before cessation of treatment.
Key Points
Fungal infection rarely causes disease in nonhuman primates, because it usually occurs in immunocompromised individuals.
Some fungal infections in nonhuman primates are reportable in certain US states.
Chronic treatment, combined with improvements in husbandry, might be required to effectively cure fungal infections in nonhuman primates.
