Zoonotic Potential of Cryptococcus spp. in Donkeys: An Urgent Public Health Issue in Egypt

Cryptococcus is an emerging fungus that has gained medical importance over the last decade, as it causes life-threatening infections in both humans and animals. In Egypt, there is limited information about the epidemiology, ecology, and pathogenesis of Cryptococcus spp. in donkeys. Therefore, the current study was carried out to investigate the occurrence and molecular characteristics of Cryptococcus species among healthy and diseased donkeys and its possible role in the epidemiology of such pathogen in Egypt. A total of 52 nasal swabs were collected from apparently healthy (n=38) and diseased donkeys (n=14) at different localities in Egypt including Cairo, Giza, and El-Fayoum Governorates. Bacteriological examination and identification of Cryptococcus spp. were performed. Molecular serotyping of Cryptococcus spp was determined by multiplex PCR using CNa-70S/A- CNb-49S/A. The virulence genes (LAC1, CAP59, and PLB1) of the identified isolates were detected by PCR. Our results showed that the overall occurrence of Cryptococcus spp. in donkeys was 11.5%. The highest proportion was in El-Fayoum, while Cairo and Giza's governorates trailed behind with 10% and 8.8% respectively. Phenotypic identification of Cryptococcus indicated that 13.2 % and 7.1% among healthy and diseased donkeys were positive for this pathogen, respectively. Donkeys older than 10 years had the most Cryptococcus spp. infections (14.3%), followed by donkeys from 1 to 5 years (12.1%) and donkeys from 6 to 10 years (8.3%), while in both males (11.4%) and females (11.8%) the pathogen was almost identical. Statistical analysis of the potential risk factors associated with Cryptococcus colonization in the donkeys did not show any significant differences. Molecular serotyping of the Cryptococcus spp. isolates (n=6) evidenced C. gattii (B) in the nasal passages of 4 healthy donkeys (7.7%); while the other 2 C. neoformans (A) (3.8%) isolates identified in healthy and diseased donkeys. Among the virulence genes detected, four C. gattii and C. neoformans isolates had higher levels of laccase (LAC1) genes. The other 2 C. gattii isolates had capsular associated protein (CAP59) gene either alone or associated with LAC1 gene. None of the species had the Phospholipase gene. This study underlines a potential association of those fungi with human disease in Egypt. In order to strengthen existing therapeutic and control approaches, further analyses of the main risk factors and the other virulence of these pathogens should be further considered.