Disease surveillance of the amphibian chytrid fungus Batrachochytrium dendrobatidis in Papua New Guinea

Abstract

Emerging infectious diseases threaten the persistence of biodiversity globally. The amphibian chytrid fungus, Batrachochytrium dendrobatidis, is one of the most widespread and damaging pathogens to biodiversity. New Guinea hosts 6% of the world's frogs and is the largest landmass where B. dendrobatidis remains undetected despite being largely climatically suitable for its persistence. We surveyed for B. dendrobatidis in Papua New Guinea, by swabbing live frogs in the Gulf Province and Eastern Highlands Province and by examining museum specimens from a range of sites and elevations. Here, we show that over a large geographical range, all 442 samples were negative for B. dendrobatidis. The spread of B. dendrobatidis to Papua New Guinea may have been thus far prevented by the remoteness of New Guinea and the hotter climate in its lowlands, which surrounds a more climatically suitable zone for B. dendrobatidis in the highlands. Alternatively, B. dendrobatidis may be present in isolated patches or at low levels and remain undetected, to date. Papua New Guinea remains at risk and would benefit from a national disease surveillance program for chytrid fungi and pre‐emptive actions, designed to reduce the risk of pathogen transmission. Measures should include improved biosecurity protocols for trade and travel and continued disease surveillance in areas of probable entry and spread.

Endemic Lineages of Batrachochytrium dendrobatidis Are Associated With Reduced Chytridiomycosis-Induced Mortality in Amphibians: Evidence From a Meta-Analysis of Experimental Infection Studies

“…A notable exception to this overall pattern was Fu and Waldman (18), in which L. caerulea experienced high mortality from both Bd-Asia1 and Bd-GPL. The L. caerulea frogs used in this study were collected in New Guinea, which as of 2020 was entirely Bd-free (47). When compared with the other species in this study (Hyla japonica, Bufo gargarizans, and Bombina orientalis), which were collected from South Korea where Bd-Asia1 is historically endemic and widely distributed today (48), the pattern of disparity in outcomes due to differences in historical host adaptation opportunity is exemplified: Korean amphibians showed low mortality in both Bd-Asia1 and Bd-GPL treatments, suggesting that a long history with Bd-Asia1 may have led to evolution of broad Bd tolerance or resistance in these species.…”

The interplay of fungal and bacterial microbiomes on rainforest frogs following a disease outbreak

“…More laboratory trials are needed to elucidate this further. It would also be invaluable for researchers to collect and archive samples from sites that are not currently infected but are likely to become infected (e.g., Papua New Guinea) so that cause and effect can be disentangled in the future (Bower et al, 2017(Bower et al, , 2020.…”

Apparent absence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) in frogs in Malaita Province, Solomon Islands

“…Further surveys for the pathogen are necessary across the Solomon Islands archipelago, but a precautionary approach should be taken -management strategies and disease surveillance protocols that assume B. dendrobatidis has not yet been introduced to the Solomon Islands archipelago and that native amphibians may be at risk of impact if the fungus is introduced, should be implemented. We echo recent calls for action for an international, multidisciplinary approach to reduce the chances of the pathogen being imported into Melanesia, and limit its impact if it is (Bower et al 2019(Bower et al , 2020. Strategies should focus on preventing its importation, including via tourism, logging, and mining activities.…”

“…Human movements and commercial trade have been linked to international movement of B. dendrobatidis (Fisher and Garner 2007;Schloegel et al 2009;Farrer et al 2011). Despite its near-ubiquitous distribution, B. dendrobatidis has yet to be detected in Melanesia, with surveys of frogs in Papua New Guinea (Swei et al 2011;Dahl et al 2012;Bower et al 2020) and Fiji (Narayan et al 2011) failing to detect the pathogen.…”