Prevalence of Batrachochytrium dendrobatidis in Amphibians From 2000 to 2021: A Global Systematic Review and Meta-Analysis

Abstract

Chytridiomycosis is an amphibian fungal disease caused by Batrachochytrium dendrobatidis (Bd), which has caused large-scale death and population declines on several continents around the world. To determine the current status of Bd infection in amphibians, we conducted a global meta-analysis. Using PubMed, ScienceDirect, SpringerLink, China National Knowledge Infrastructure (CNKI) and Wanfang database searches, we retrieved a total of 111 articles from 2000 to 2021. Based on these, we estimated the Bd prevalence to be 18.54% (95% CI: 13.76–20.52) in current extent amphibians. Among these populations, the prevalence of Bd in Asia was the lowest at 7.88% (95% CI: 1.92–8.71). Further, no Bd infection was found in Vietnam. However, the prevalence of Bd in Oceania was the highest at 36.34% (95% CI: 11.31–46.52). The Bd prevalence in Venezuela was as high as 49.77% (95% CI: 45.92–53.62). After 2009, the global Bd prevalence decreased to 18.91% (95% CI: 13.23–21.56). The prevalence of Bd in epizootic populations was significantly higher than enzootic populations. The highest prevalence of Bd was detected with real-time PCR at 20.11% (95% CI: 13.12–21.38). The prevalence of Bd in frogs was the highest at 20.04% (95% CI: 13.52–21.71), and this different host was statistically significant (P < 0.05). At the same time, we analyzed the geographic factors (longitude, latitude, elevation, rainfall and temperature) that impacted the fungal prevalence in amphibians. Our meta-analysis revealed that factors including region, disease dynamic, detection method, host and climate may be sources of the observed heterogeneity. These results indicate that chytridiomycosis was a consistent threat to amphibians from 2000 to 2021. Based on different habitat types and geographical conditions, we recommend formulating corresponding control plans and adopting reasonable and efficient biological or chemical methods to reduce the severity of such diseases.

Tourism may threaten wildlife disease refugia

“…9% (8/93), which is substantial. Courtois et al (2015) reported a prevalence of 6% in French Guiana (eastern Guiana Shield) where human disturbance is widespread across the studied sites, while Bd prevalence in the Venezuelan Andes has been estimated to be as high as 49.8% (Li et al, 2021based on Sánchez et al, 2008. Since infection load needs time to build up, the overall low prevalence in Pantepui may also reflect a recent introduction.…”

Modeling the Distribution of the Chytrid Fungus Batrachochytrium dendrobatidis with Special Reference to Ukraine

“…It is worth noting here that elevation is amongst the topographical variables repeatedly considered important for shaping the distribution of Bd. Findings in this respect ranged from establishing evidence of a positive correlation of the pathogen occurrence with elevation [ 89 , 90 ] to the negation of any such correlation [ 91 ]. In our case, it was notable that the BART algorithm fully excluded ‘elevation’ from the model.…”

Pathogens in anurans from a seasonal tropical environment in Guanajuato, Mexico

“…In Mexico, the incidence of Batrachochytrium dendrobatidis has increased to 46.1%, higher than in other countries in the Americas such as Costa Rica (20.1%) and Brazil (32.7%). The only country in the Americas with a higher overall prevalence than that in Mexico is Venezuela (49.7%; Zhongle et al, 2021).…”