Seasonal variation in the prevalence of a fungal pathogen and unexpected clearance from infection in a susceptible frog species

Title
Seasonal variation in the prevalence of a fungal pathogen and unexpected clearance from infection in a susceptible frog species
Publication Date
2022
Author(s)
Garnham, James I
Bower, Deborah
( author )
OrcID: https://orcid.org/0000-0003-0188-3290
Email: dbower3@une.edu.au
UNE Id une-id:dbower3
Stockwell, Michelle P
Pickett, Evan J
Pollard, Carla J
Clulow, John
Mahony, Michael J
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Inter-Research
Place of publication
Germany
DOI
10.3354/dao03628
UNE publication id
une:1959.11/52556
Abstract

The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causes the disease chytridiomycosis, which is a primary driver for amphibian population declines and extinctions worldwide. For highly susceptible species, such as the green and golden bell frog Litoria aurea, large numbers of Bd-related mortalities are thought to occur during the colder season (winter), when low temperatures favour the growth of the pathogen. However, extant L. aurea populations are persisting with Bd. We measured Bd prevalence and infection levels of wild L. aurea using capture-mark-recapture and radio-tracking methods. Using this information, we sought to determine host and environmental correlates of Bd prevalence and infection load. Mean ± SE infection load was higher in frogs sampled in autumn (431.5 ± 310.4 genomic equivalents; GE) and winter (1147.5 ± 735.8 GE), compared to spring (21.8 ± 19.3 GE) and summer (0.9 ± 0.8 GE). Furthermore, prevalence of Bd infection in L. aurea was highest in winter (43.6%; 95% CI 33.1-54.7%) and lowest in summer (11.2%; 95% CI 6.8-17.9%). Both prevalence and infection load decreased with increasing temperature. Seven frogs cleared their fungal infection during the coolest months when Bd prevalence was highest; however, these clearances were not permanent, as 5 frogs became infected again. Understanding the factors that allow amphibians to clear their Bd infections when temperatures are optimal for Bd growth presents the potential for manipulating such factors and provides an important step in future research.

Link
Citation
Diseases of Aquatic Organisms, v.148, p. 1-11
ISSN
1616-1580
0177-5103
Pubmed ID
35142293
Start page
1
End page
11

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