Mange outbreak decimated a wild vicuna population in Argentina
Domestic llamas may have been source of epidemic: Cascading consequences expected

Date:
January 21, 2022
Source:
University of California - Davis
Summary:
Mange has decimated the population of wild vicunas and guanacos
in an Argentinian national park that was created to conserve
them, according to a new study. The findings suggest domestic
llamas introduced to the site may have been the source of the
outbreak. Cascading consequences for local predator and scavenger
species are expected.



FULL STORY ========================================================================== Mange has decimated the population of wild vicun~as and guanacos in an Argentinian national park that was created to conserve them, according
to a study from the Administration of National Parks in Argentina and
the University of California, Davis.


==========================================================================
The findings, published today in the journal PLOS ONE, suggest
domestic llamas introduced to the site may have been the source of the outbreak. Cascading consequences for local predator and scavenger species
are expected.

Vicun~as and guanacos are species of wild camelids native to Argentina,
Chile, Bolivia, Ecuador and Peru, where the vicun~a is the national
animal.

The study investigated the impacts and origins of the outbreak, which
began in 2014 in San Guillermo National Park.

"This part of Argentina used to be the Serengeti of the wild camelids,"
said corresponding author Marcela Uhart, who directs the Karen C. Drayer Wildlife Health Center's Latin America Program, within the UC Davis
School of Veterinary Medicine and its One Health Institute. "Now you
go and it's empty, and whoever is there is mangy. This disease is not
novel. We know mange. It's a common mite. But significant outbreaks are happening in several wildlife species around the world." Home on the
mange During the study, the authors observed signs of sarcoptic mange
in a quarter of living vicun~as, a third of live guanacos, and in nearly
all dead vicun~as and guanacos.



========================================================================== Between 2013 and the onset of the study in 2017, populations of guanaco
and vicun~a were down 95% and 98%, respectively. Nearly three-quarters
more were lost between 2017-18 alone. By 2019, researchers could no
longer find either animal during the study surveys.

Sarcoptic mange is a highly contagious disease in which mites burrow under
the animal's skin, which becomes thick, crusty, itchy and cracked. Because
it becomes too painful to move and forage, many animals starve or become
easy prey.

Mites from sevenvicun~as and three guanacos were collected and analyzed
in the lab of co-author Janet Foley, a disease ecologist in the UC Davis
School of Veterinary Medicine. They found the mites shared the same
genotype, indicating a single source and recent origin of the epidemic.

The authors traced a potential source to a governmental livestock
incentive program that introduced llamas to areas near the park in 2009,
some of which had mange, which is rarely fatal for llamas.

No infected llamas were available at the time of the study, so the
authors couldn't collect mites from them to compare with mites found
on the vicun~as and guanacos. But the findings combine to suggest that introducing mange- infected llamas may have triggered the outbreak.



========================================================================== Cascading consequences In several countries wild vicun~as provide a source
of income for Indigenous communities, who shear the live animals for their soft, valuable fiber. The animals also play a key role in maintaining
a balanced ecosystem in the vast high Andes plateau, or altiplano. Once
hunted nearly to extinction, the population in South America is considered
a conservation success story, having rebounded once strict enforcement
of the fiber trade and bans on lethal shearing were enacted in the 1980s.

While global populations of vicun~as and guanacos are still considered
healthy, the outbreak at San Guillermo is expected to bring cascading consequences for local predators and scavengers.

Vicun~as and guanacos are important prey species for mountain lions,
and condors feast on the remaining carcasses. Without wild herbivores on
the menu, the mountain lions may turn to local livestock for their meals
unless and until wild camelid populations can rebound. Condors may also
have to search for food outside the park, exposing them to risks such
as poisoning by pesticides or lead from hunting ammunition.

"Hopefully, within a few years, the animals will slowly return,"
Uhart said.

"But in the meantime, we don't know what will happen with the predators
and scavengers because there is basically nothing left for them to eat."
One Health approach needed The authors note that better and ongoing communication between the conservation and livestock sectors might have
warded off the outbreak and could help prevent future disease.

"Several factors combined to create the perfect storm of this epidemic at
a high cost to the ecosystem of San Guillermo National Park," said lead
author Hebe del Valle Ferreyra, a wildlife veterinarian with the national
parks service in Argentina. "Animal health management, conservation
and agriculture should not be regarded as opposing, incompatible and disconnected activities. A change of approach is needed that recognizes
the links between all these sectors." Additional co-authors in the study include Jaime Rudd and Ralph Vanstreels of UC Davis, Ana M. Marti'n of Universidad Cato'lica de Co'rdoba in Argentina, and Emiliano Donadio
of the National Scientific and Technical Research Council (CONICET)
in Argentina.

The research was supported by San Guillermo National Park, Administracio'n
de Parques Nacionales in Argentina, UC Davis, National University of
Co'rdoba, and the U.S. Fish and Wildlife Service.

========================================================================== Story Source: Materials provided by
University_of_California_-_Davis. Original written by Kat Kerlin. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hebe del Valle Ferreyra, Jaime Rudd, Janet Foley, Ralph
E. T. Vanstreels,
Ana M. Marti'n, Emiliano Donadio, Marcela M. Uhart. Sarcoptic
mange outbreak decimates South American wild camelid populations
in San Guillermo National Park, Argentina. PLOS ONE, 2022; 17 (1):
e0256616 DOI: 10.1371/journal.pone.0256616 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220121145407.htm

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