Phaeohyphomycosis Caused by Cochliobolus hawaiiensis in a Camel Farm in Saudi Arabia: An Emerging Disease

Phaeohyphomycosis describes subcutaneous lesions caused by dematiaceous fungi, brown-pigmented mould. In a camel farm in Saudi Arabia, the owner complained of cases of skin infection among camels. Lesions persisted after sarcoptic mange outbreak which was treated until the infection resolved. General examination revealed that four camels were affected showing alopecia, erythema, numerous small subcutaneous nodules and brownish blackish crusts. To collect specimens, affected areas were disinfected with 70% ethyl alcohol and deep were taken. Skin scrapings were prepared in 10% potassium hydroxide for microbiological examination. Cultures were done onto Sabouraud dextrose agar (SDA) with chloramphenicol 0.5 mg per ml, incubated at 30⁰C and another set with chloramphenicol 0.5 mg per ml and cycloheximide (Sigma), 0.4 mg/L, incubated at 27⁰C and 37⁰C. Molecular mycology analysis was done by Polymerase Chain Reaction (PCR) on internal transcribed spacer (ITS) gene using ITS1 and ITS4 primers.

Microscopic examination indicated it was negative for dermatophytes. It showed brownish to black, septate hyphae arranged as arthro-hyphae, and black yeast-like particles. Cultures yielded multiple, velvety, gray colonies turning brownish black later. Lactophenol cotton-blue smears revealed septate, branched hyphae that are dark brown in colour1.5–5 μ wide. Conidiophores are septate, unbranched with flexuose apexes, bearing brown, multi-septate, cylindrical conidia. ITS gene sequence analysis confirmed the isolate from camel skin scrapings to be Cochliobolus hawaiiensis. The case is interesting as this represents, to the best of our knowledge, the first authenticated report of C. hawaiiensis in animals from a tropical country.