Mosquitoes may be spreading a big problem for amphibians

Jose Valdez
Nov 7 · 2 min read
Mosquito on frog. Credit: John Gould

Mosquitoes kill more people than any other animal in the world through their transmission of infectious diseases. Now, scientists have evidence to suggest mosquitoes might also play a role in the decline of amphibians by transmitting a deadly fungus.

The amphibian chytrid fungus, Batrachochytrium dendrobatidis, is an infectious disease that is thought to be a primary culprit in the global decline and extinction of many amphibian species. Despite its severe and continuing impact, very little is known about how it has spread so rapidly between populations.

Research scientists at the University of Newcastle, led by John Gould, have shed some light onto this aspect of the disease by revealing adult mosquitoes have the capacity to carry and then transfer the fungus on its legs to new uninfected locations. Their findings have been presented in a study published in Zoology and Ecology.

To determine whether mosquitoes could transmit the fungus, individuals were exposed to surfaces infected with the fungus. “Only adult females were analysed in this study,” says co-author Jose Valdez, “they are the only sex that bite and feed on blood which they use to produce their eggs.” Using a technique called polymerase chain reaction (PCR), that allows the DNA of any given species to be detected, the fungus was found to be present on the legs of mosquitoes that landed on the infected surfaces. Later, the fungus was also found on clean sterile surfaces after these mosquitoes landed on them.

“This study is important as it is the first to demonstrate that an insect host may be a vector of the chytrid fungus and suggests that it might account for how rapidly it has spread in the wild,” says Gould. The next step for the team will be to determine whether live fungal spores can be transmitted between infected and non-infected amphibians and start a new cycle of disease.

Research article:

Gould J., Valdez J.W., Stockwell M.P., Clulow J., Mahony M. Mosquitoes as a potential vector for the transmission of the amphibian chytrid fungus. Zoology and Ecology 29(1), 38–44. doi: https://doi.org/10.35513/21658005.2019.1.5

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