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Published Date: 2019-01-22 11:00:39
Subject: PRO/AH/EDR> Pneumonia ovine - USA (02): (CA) bighorn sheep
Archive Number: 20190122.6270994
PNEUMONIA OVINE - USA (02): (CALIFORNIA) BIGHORN SHEEP
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Date: Thu 17 Jan 2019 4:43 p.m. PT
Source: Standard-Examiner [edited]
https://www.desertsun.com/story/news/2019/01/17/bighorn-sheep-dying-california-desert/2603545002/


At least 20 desert bighorn sheep have died in a San Gorgonio mountain population in Southern California, 100 miles [about 161 km] east of Los Angeles. The cause of death? Pneumonia, most likely from domestic sheep or goats, though wildlife specialists are examining other possible causes, including pathogens from feral cattle to the west and disease from a different bighorn group to the south.

"Since the beginning of December [2018], I have recovered 20 dead sheep, and I suspect that's just a portion of what's occurring," said Jeffrey Villepique, a wildlife biologist with the California Department of Fish and Wildlife inland deserts region who is leading the probe into the deaths.

A known herd of about 200 of the sheep has long lived and grazed in the area, from Mission Creek and Whitewater Canyon up miles of rugged slope to the peak of Mt San Gorgonio. Villepique and a fellow biologist have been hiking across the hills for the past several weeks and have seen less than 1/3 of the numbers of live sheep they would expect.

"All it takes is this disease introduction event to potentially wreak havoc on healthy populations," he said. Notably, all ages are dying, from large rams to lambs. Groups of dead sheep have been found together -- while shy of humans and wary of predators, bighorns are extremely gregarious with each other, rubbing noses and foraging on the same grasses. That means the disease can spread rapidly.

"It's really tragic," said Jack Thompson, regional director for The Wildlands Conservancy, a nonprofit that manages Whitewater Preserve, near where many of the dead sheep have been found. "The bighorn sheep are such an iconic species for the California desert."

Thompson said the chance to see "a really amazing animal" is part of what draws visitors to the area. "They have an encounter with it," he said." So, seeing them die, personally, is really, really sad."

Thompson said his staff started seeing suspect dead sheep in November [2018]. The 1st was found roadside on [15 Nov 2018], just north of the unincorporated community of Bonnie Bell. On [28 Nov 2018], another dead ram was reported in a riverbed in the same area. That day, rangers also encountered a live bighorn "acting loopy" just north of the community.

"It was walking in a fashion where it obviously seemed like it was having some kind of trouble," Thompson explained. "It was confused and should have been more disturbed by the presence of people. That was the 1st time we saw one that we said, 'There's obviously something going on here. This is a sick animal.'"

Villepique said he heard reports of dead sheep in November [2018] from a UC [University of California] Riverside graduate student and the conservancy, but at first chalked up one death to normal predation, possibly by a mountain lion, and the 2nd to a collision with a car.

But when he heard a report of a large male that had been standing by the side of the road for 24 hours straight, he thought, "Uh oh," and decided it was time to investigate.

"It was clear this animal appeared to be ill," he recalled, with its snout pointed downward and its ears sagging. Also odd was that a 5-year-old ram would let a ranger get within 30 feet [9 m] and tranquilize him with a dart.

Once the animal was immobilized, a trained wildlife veterinarian determined it was in extremely poor shape. It was euthanized and immediately shipped to a special facility at UC Davis, the California Animal Health and Food Safety laboratory, where wildlife pathologists have been trying to crack the riddle of what killed the ram and nearly 2 dozen more sheep from the same population.

"The initial evaluation is this ram had pneumonia, which is just another way of saying a whole bunch of fluid in the lungs," said Villepique. "We've been trying to identify the pathogen or pathogens responsible for that pneumonia, and we're still working to try to identify the source of the pathogen."

Since then, state biologists, rangers, and area volunteers have found increasing numbers of sick and dead animals. Many were emaciated and coughing badly. Samples were taken from the animals and shipped to the Davis research lab "to try to tease out which pathogen or multiple pathogens are causing this," said Villepique.

In total, 4 dead sheep were found by or reported to Whitewater Preserve rangers in early December [2018].

On [27 Dec 2018], the remains of 7 young males or ewes were found by Whitewater Preserve rangers on the east side of the canyon, after reports from hikers. "You'll find groups that together have walked to a point and all are obviously infected by the same thing, and they all just sit down and die together," said Thompson.

On [10 Jan 2019], 2 more bighorn were reported dead east of Bonnie Bell.

Villepique has recovered all those animals and 7 more.

He hopes subgroups of the San Gorgonio population have headed for higher elevations and will survive unscathed.

--
Communicated by:
ProMED-mail from HealthMap Alerts
<promed@promedmail.org>

[Bighorn sheep pneumonia has traditionally been considered a multifactorial disease, caused by multiple pathogens. Due to their complexity, understanding multifactorial phenomena like these usually requires integrated and sustained research efforts. The absence of established and universal explanations for pneumonia outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices.

Bighorn sheep pneumonia web of causation may have an important environmental component. In recent years, die-offs of bighorn sheep in several locations suggests that the proximate cause of these events may be a shared environmental determinant.

However, recent evidence indicates that in northwestern USA there seems to be a pathogen implicated in bighorn sheep outbreaks, _Mycoplasma ovipneumoniae_, an exotic disease agent for North America, introduced by domestic ovids.

For a picture of a bighorn sheep go to http://b50ym1n8ryw31pmkr4671ui1c64.wpengine.netdna-cdn.com/wp-content/blogs.dir/11/files/2013/09/Bighorn_Cal-Bebee-620x411.jpeg.-Mod.PMB

HealthMap/ProMED-mail map of California, United States: http://healthmap.org/promed/p/204]

See Also

Pneumonia ovine - USA: (UT) bighorn sheep 20190114.6257417
2018
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Pneumonia, ovine - USA (03): (UT,NV) bighorn sheep 20180806.5949871
2016
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Pneumonia ovine - USA (07): (SD) bighorn sheep 20161223.4719622
Pneumonia, ovine - USA (06): (MT) bighorn sheep 20161107.4611801
Pneumonia, ovine - USA (05): (CA) bighorn sheep 20160519.4232401
Pneumonia, ovine - USA (04): (NV) bighorn sheep 20160409.4149360
Pneumonia, ovine - USA (03): (NV) bighorn sheep 20160219.4033226
Pneumonia, ovine - USA (02): (AZ) bighorn sheep 20160109.3923355
Pneumonia, ovine - USA: (AZ) bighorn sheep 20160105.3911283
2015
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Pneumonia, ovine - USA (04): (CA) bighorn sheep 20151014.3714877
Pneumonia, ovine - USA (03): (ND) bighorn sheep 20150920.3659146
Pneumonia ovine - USA (02): (MT) bighorn sheep 20150409.3286818
Pneumonia, ovine - USA: (MT) bighorn sheep 20150121.31069442014
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Pneumonia, ovine - USA: (MT) bighorn sheep 20141229.3060886
2013
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Pneumonia ovine - USA (04): (CA) bighorn sheep 20130817.1885956
Pneumonia ovine - USA (03): (CA) bighorn sheep 20130626.1794259
Pneumonia, ovine - USA (02): (WA) bighorn sheep, comment 20130430.1680888
Pneumonia, ovine - USA: (WA) bighorn sheep, euthanasia 20130407.1628473
2012
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Pneumonia, ovine - USA: (WY) bighorn sheep, susp. 20130130.1520984
and other items in the archives
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