Nannizziopsis vriesii
| Nannizziopsis vriesii | |
|---|---|
| Scientific classification | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Eurotiomycetes |
| Order: | Onygenales |
| Family: | Onygenaceae |
| Genus: | Nannizziopsis |
| Species: | N. vriesii |
| Binomial name | |
| Nannizziopsis vriesii | |
| Synonyms | |
| |
Nannizziopsis vreisii is a keratinophilic microfungus in the Family Onygenaceae which includes both dematophytes and saprophytic species.[1] The ecology of N. vriessi is not well known, but several studies have demonstrated that the Chrysosporium anamorph of N. vriesii causes skin lesions in reptiles.[2] This species can be identified by looking for characteristics such as white ascomata, and hyaline and globose ascopores.[3] Like many other fungi, N. vreisii has a sexual and asexual state, and the asexual state are named under Chryososporium, Malbranchea or Sporendonema.[1]
Taxonomy and naming
Nannizziopsis vreiisi was first described under in the genus Rollandina which was erected by Patouillard in 1905.[4] In 1970, Benjamin and Apinis amended the genus Rollandina and added several new species, including R. vriesii.[4] Apinis placed Rollandina vreissi under Rollanda because of the characteristics of the hyphae found in Patouillard's collection.[1]The genus Nannizziopsis was first believed to be a synonym of Arachnotheca, but upon further examination, enough distinguishing features were observed between species of Nannizziopsis and Arachnotheca to make them unique.[3] Currah treated Rollandina vriesii in the Onygenaceae because of its ability to degrade keratin, as demonstrated by hair perforation, and the presence of spheroidal ascospores with punctate walls.[1]
Cultural characteristics
Nannizziopsis vriesii produces dense colonies that can reach a diameter of 25–30 mm in 14 days.[4] The culture appears to be white and powdery and the reverse side is observed to be yellowish in color.[4] Isolates are shown to have strong urease activity and are mesophilic; displaying optimum growth at 30 °C.[5] Furthermore, growth of N. vreisii is inhibited at temperatures below 20 °C and at temperatures above 37 °C.[4] Unlike some closely related fungi, N. vriesii does not require an exogenous source of the vitamins thiamine or inositol for growth.[5]
Morphology
The sexual stage of N. vriesii consists of a 1 mm in diameter, whitish tumble-weed like fruiting body containing a central cluster of asci containing ascospores.[1] The hyphae comprising the exterior of the fruiting body are characteristically rough-walled with septal constrictions.[1] The lens shaped ascopores are brown in color and range in size from 2-3 μm.[3] Like other members in the family Onygenacae, N. vriesii produces rhexolytically dehiscing conidia.[1] The conidia are either teardrop shaped or club-shaped, and form directly on the sides of the hyphae.[5]
Pathogenicity in reptiles
Several studies have shown that the Chrysosporium anamorph of Nannizziopsis vriesii (CANV) causes dermatitis and cellulitis in reptiles. Skin lesions as well as poor nutrition make retiles more prone to infection and once the skin is infected, it can potentially transition into a condition called fatal yellow fungus disease.[6] Unlike other fungi, which infect reptiles, infections with N. vreisii are contagious and often fatal if not treated.[6] Treatment with thiabendazole or ketoconazole is suggested when infection becomes systemic.[7] Other suggested treated for infection is long-term treatment of itaconazole combined with removal of infected skin regions.[6] CANV was isolated from the skin of chameleons and lesions improved with treatment of itaconazole.[5] It has also been isolated from the skin lesions of geckos.[8] A recent review described a series of cases of infected coastal bearded dragons showing nodular lesions and crusty debris on the skin.[6] These infections tend to resistant treatment, however certain agents may have some limited effectiveness, including: triamcinolone acetonide, neomycin, thiostrepton, nystatin.[6] A related fungus, Ophidiomyces ophiodiicola, is responsible for an important disease of snakes.
References
- 1 2 3 4 5 6 7 Currah, R.S (October–December 1985). "Taxonomy of the Onygenales: Arthodermatacae, Gymnoasceae, Myxotrichaceae and Onygenaceae". Mycotaxon. 24: 1–216.
- ↑ http://www.uamh.devonian.ualberta.ca/~/media/uamh/CollectionActivities/Documents/UAMH_Annual_Report_2012F.pdf
- 1 2 3 Guarro, J; Cano, J; Vroey, C (October–December 1991). "Nannizziopsis (Ascomycotina) and Related Genera". Mycotaxon. 42: 193–200.
- 1 2 3 4 5 Apinis, A.E (December 1970). "Concerning Rollandina". Transactions of the British Mycological Society. 55: 499–502. doi:10.1016/s0007-1536(70)80075-4.
- 1 2 3 4 Paré, J.A.; Sigler, L; Hunter, B; Summerbell, R; Smith, D; Machin, K (1997). "Cutaneous Mycoses in Chameleons Caused by the Chrysosporium Anamorph of Nannizziosis Vreissi (Apinis) Currah". Journal of Zoo and Wildlife Medecine. 28: 443–453.
- 1 2 3 4 5 Johnson, R; Sigler, C; Sangster, C; Paré, J (December 2011). "Deep fungal dermatitis caused by the Chrysosporium anamorph of Nannizziopsis vriesii in captive coastal bearded dragons (Pogona barbata)". Australian Veterinary Journal. 89: 515–519. doi:10.1111/j.1751-0813.2011.00851.x.
- ↑ http://www.merckmanuals.com/vet/exotic_and_laboratory_animals/reptiles/mycotic_diseases_of_reptiles.html
- ↑ Toplon, D. E.; Terrell, S; Sigler, L; Jacobson, E (16 November 2012). "Dermatitis and Cellulitis in Leopard (Eublepharis) Caused by the Chrysosporium Anamorph of Nannizziopsis vreissi". Veterinary Pathology. 50: 585–589. doi:10.1177/0300985812465324.