Burmese pythons in Florida's Everglades are carrying three previously unknown RNA viruses, raising questions about whether viruses harboured by the invasive snakes could eventually affect native wildlife.
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viruses → carry → wildlife
A study published in the Journal of Virology examined 40 Burmese pythons captured in and around the site of a 2020 disease outbreak among eastern mudsnakes.
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study → publish → mudsnakes
Researchers did not find the ferlavirus linked to that outbreak in the pythons, but instead identified three previously undescribed viruses: an alphavirus, a hepacivirus and an arterivirus.
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Researchers → find → viruses
They also detected a previously characterised serpentovirus.
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They → detect → serpentovirus
While the findings expand knowledge of viruses carried by invasive reptiles, researchers say further work is needed to determine whether any of these viruses can infect native snakes.
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any → expand → snakes
Florida’s Burmese pythons found carrying new RNA viruses
The research began after an outbreak among eastern mudsnakes in the Greater Everglades Ecosystem during November and December 2020.
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research → find → November
Some affected snakes were found writhing on riverbanks with frothy oral discharge, while examinations revealed necrotising enteritis and pulmonary oedema.
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examinations → find → enteritis
Scientists isolated a reptilian ferlavirus from the sick mudsnakes.
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Scientists → isolate → mudsnakes
Ferlaviruses are known to cause serious and sometimes fatal disease in snakes kept in managed settings, but this was the first recognised outbreak in free-ranging snakes.
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this → know → snakes
Because the virus was genetically related to viruses previously found in captive anacondas, researchers investigated whether an invasive constrictor species in the Everglades might be involved in its ecology.
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species → relate → ecology
Researchers tested 40 Burmese pythons
Researchers collected oral and vent swabs from 40 Burmese pythons captured in and around the outbreak area.
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Researchers → test → area
None tested positive for the ferlavirus found in the mudsnakes.
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None → test → mudsnakes
Instead, RNA sequencing revealed three previously undescribed viruses: Eden alphavirus, Burmese python hepacivirus and Burmese python arterivirus.
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sequencing → reveal → viruses
The researchers also detected Burmese python septoviruses, a group of serpentoviruses previously identified in South Florida's Burmese pythons.
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researchers → detect → pythons
Eden alphavirus was found in nearly one-third of pythons
Eden alphavirus, or EDEV, belongs to the genus Alphavirus in the family Togaviridae.
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alphavirus → find → Togaviridae
Researchers detected it in 12 of the 40 pythons, or 30%.
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Researchers → detect → pythons
Most detections came from vent samples.
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detections → come → samples
Only a partial viral sequence was recovered, and attempts to grow the virus in laboratory cell cultures were unsuccessful.
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attempts → recover → cultures
EDEV's closest known relatives include Caainguá virus, first identified in mosquito pools in Brazil.
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relatives → know → Brazil
The researchers describe EDEV as the first new terrestrial alphavirus detected in the continental US in more than 50 years.
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researchers → describe → years
However, its ability to cause disease remains unknown, and the study provides no evidence that it infects humans.
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it → cause → humans
A new hepacivirus was found in most of the snakes
Burmese python hepacivirus, or BuPyHV, was the most frequently detected of the three newly identified viruses.
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hepacivirus → find → viruses
It was found in 26 of the 40 pythons, meaning 65% had detectable viral RNA.
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% → find → RNA
The virus belongs to the genus Hepacivirus in the family Flaviviridae and is described by the researchers as the first hepacivirus identified in a snake.
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virus → belong → snake
Although the genus also includes hepatitis C virus, BuPyHV is genetically distinct, and there is no evidence that it causes hepatitis in humans.
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it → include → humans
Researchers identified an unusually elongated region in its genome and a possible additional protease-related protein whose function remains unknown.
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function → identify → genome
The third novel virus, provisionally named Burmese python arterivirus or BuPyAV, was detected in four of the 40 pythons, or 10%.
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virus → name → pythons
It belongs to the family Arteriviridae.
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It → belong → Arteriviridae
Researchers recovered only a short section of its genome, limiting what they could determine about its evolution.
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they → recover → evolution
Its closest known relative was a greater green snake arterivirus identified in China.
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relative → know → China
The study describes BuPyAV as the first reptilian arterivirus reported from North America.
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study → describe → America
Its ability to cause disease or spread between animals has yet to be established.
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ability → cause → animals
More than half of the pythons carried multiple viruses
The researchers found that many of the pythons carried more than one virus.
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many → carry → virus
Two or three viruses were detected in 23 of the 40 animals, representing 57.5% of the sample.
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viruses → detect → sample
The most common combination was Burmese python hepacivirus and serpentovirus, detected together in nine pythons.
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combination → detect → pythons
Eden alphavirus and hepacivirus were found together in seven.
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alphavirus → find → seven
The serpentoviruses identified in the study have previously been associated with respiratory disease in captive snakes.
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serpentoviruses → identify → snakes
However, detecting viral RNA does not by itself establish that a particular snake was ill because of the virus.
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snake → detect → virus
Cross-species transmission remains an open question
The findings do not show that any of the three newly identified viruses have already spread from Burmese pythons to native snakes.
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any → show → snakes
Researchers instead identify cross-species transmission as an issue that warrants further investigation.
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that → identify → investigation
…and 9 more, not listed.
The Aporia
