Harmful Algal Blooms and Livestock Concerns - North Central ...
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Harmful Algal Blooms
and Livestock Concerns
Michelle Mostrom,
DVM, MS, PhD, DABVT, DABT (1995-2020)
North Dakota Veterinary Diagnostic Lab
Fargo, ND
michelle.mostrom@ndsu.edu
Cyanobacterial bloom Sedan, Kansas (Dr. S. Ensley, K-State Veterinary Toxicologist)
A large population of
livestock (food
producing animals) are
dependent on potable
surface waters that can
have algal blooms any
time of year, depending
on geographic location.
Photo courtesy Jessie Schultz, NDSU-VDL
Duckweed and a Duck
Livestock producers
can be confused by
rapid growth of
duckweed (Lemna,
small flowering
plants) in a pond.
NY Times: Kay Nietfeld/DPA, via Getty Images
About 70 to 80% of the water submissions into several
Water submissions into Midwest Veterinary Diagnostic Labs are pro-active and
request if water “safe to use for livestock”.
Veterinary Diagnostic Labs Often unknown history or location where water sample
taken. Sometimes water samples have been kept on a
dashboard for hours and samples compromised.
Labs try to provide microscopic identification of
cyanobacteria. Cell numbers/ml often not helpful because
not all cyanobacteria are toxigenic and not all toxins are
cell-bound.
Microcystins are largely cell-bound, but this does not
occur with other cyanotoxins.
Livestock producers don’t want to spend excessive $$ for
an evaluation (rarely >$50 to $100 for sample toxin and
identification).
Want quick turn-around to move livestock onto pastures.
Consider quick tests but they do not include all toxins
potentially at risk to livestock.
The water sample is just a ‘snapshot in time’.
Sampling is critical for determining cyanobacteria/
cyanotoxins in water sources and risk for livestock
USGS. Guidelines for Design and Sampling for
Cyanobacterial Toxin and Taste-and-Odor Studies in Lakes
and Reservoirs. Jennifer L. Graham, Keith A. Loftin,
Andrew C. Ziegler, and Michael T. Meyer Scientific
Investigations Report 2008-5038.
Consider when taking water samples:
Seasonal patterns,
Environmental conditions of rains, winds and mixing,
Distribution in the water column (general location of
cyanobacteria is largely affected by lake/reservoir
hydrology and morphology)
6 general water column distributions of
cyanobacteria:
Shoreline, near-shores, open-water
surface accumulation, scums
Even distribution throughout the photic
zone
Specific depth in the photic zone
Metalimnetic bloom
Even distribution throughout the water
column
Under ice bloom
USGS. Guidelines for Design and Sampling for Cyanobacterial Toxin
and Taste-and-Odor Studies in Lakes and Reservoirs. Scientific
Investigations Report 2008-5038.
HABs – Microcystin toxicosis in nursery pigs (late fall - winter in the Midwest) Drinking water for swine facility from an adjacent pond (~ 17,000 m2) that was naturally filled via a watershed. Water was treated with hydrogen peroxide in a holding tank prior to use. 5 week-old pigs presented with clinical signs of sudden death, slow growth, distended abdomens, liver centrilobular necrosis and areas of regeneration or necrosis with hemorrhage observed histologically. Mortality during the investigation increased by about 7.5% in three affected groups of nursery pigs, with a final mortality of 11.4% and 50% of the population showing clinical signs of various degrees. Algae were observed on the surface of a small area of standing water near the pond that had a waterway to the main water supply even in winter. Water from an isolation room was positive for microcystins LR and RR (3.4 ppb and 2 ppb, respectively). Standing water with growing algae by the main pond was tested and was positive for microcystins LA, LR, RR, and YR (range of 3 to 33.7 ppb LA, 4.3 to 9.9 ppb LR, 5.4 to 14 ppb or RR, and 4.5 to 4.6 ppb or YR). Liver tissue positive for microcystin YR at 1 to 3 ppb. Case Report. Microcystin toxicosis in nursery pigs. Classen DM, Schwartz KJ, Madson D, Ensley SM. J Swine Health Prod. 2017;25(4):198-205. Photos from Dr. S. Ensley K-State
Livestock losses: Rule out bacteria and viruses, feed
toxins, heavy metals, pesticides, pollutants, lightning
strikes, and check water quality and contaminants.
Microcystin toxins inhibit phosphatases 1 and 2A in
the liver causing hemorrhage.
Microcystin toxins may also be associated with
gastroenteritis and kidney necrosis.
Microcystins can cross the blood-brain-barrier and
cause neurological clinical signs.
WHO sets a microcystin LR safe allowable limit at
1.0 ug/L (1.0 ppb) for humans. A guideline level of 1
ug Microcystis toxins/L recommended for humans
partially based on experiment with growing pigs
(Falconer IR et al. 1994, Environmental Toxicol Water
Quality 9:131-139).
Livestock exposures often occur with high cyanotoxin
concentrations in water and with sub-acute to chronic
exposures.
Photo courtesy of Dr. S. Ensley, K-State Fluctuating environmental temperature during the fall
and winter can contribute to algae dying and releasing
toxins, and subsequently growing with warming
cycles.
Sheep exposed to Microcystis aeruginosa in Australia; 17 sheep died and other showed signs of hepatogenous photosensitivity. Recovery was monitored by serum biochemistry tests and liver enzyme activity (serum gamma-glutamyl transferase) and bilirubin concentrations that decreased rapidly to normal levels in the 3 weeks post-exposure. An additional 34% of sheep died during observation period of 6 months while serum biochemical tests gave no indication of the cause of deaths. Suggesting that sublethal exposure to microcystins may cause prolonged morbidity and delayed mortality. Recovery of hepatic function and latent mortalities in sheep exposed to the blue-green alga Microcystis aeruginosa. Carbis CR, Waldron DL, et al., Vet Rec. 1995;137:12-15.
Need to stop the exposure and move animals to clean water – without stress or fence out water sources and provide alternative water. For grooming animals, bathe the animals to remove algal debris (dogs). Can have loss of pasture grazing, economic hardships+. Often veterinarians will use medications aimed at treating the observed clinical signs, which may be contra-indicated with organ malfunction. Consider stress of handling animals. Microcystin toxicity can reduce liver perfusion and lead to liver failure. Drug metabolism often requires liver blood flow and liver enzymatic function. Microcystin LR can cause a change in sodium transport in the kidney and cause kidney failure. Medications should be used with caution and the knowledge of possible compromised liver and kidney functions in affected animals.
Anabaena/Dolichospermum bloom in SE Oregon resulted
in the deaths of 32 14-month old steers in a four-day
period.
Clinical signs reported: excitation, head tremors, staggering
gait, tetany and death (most acute signs appeared
neurological). Field necropsies of several animals revealed
pale livers. Histopathology included massive liver necrosis.
Microcystin LR was identified at 3000 ug/L in a reservoir
water sample and at 7100 ug/L in rumen contents of one of
the dead steers.
Dreher TW, et al. Anabaena/ Dolichospermum as the source of lethal
microcystin levels responsible for a large cattle toxicosis event.
Toxicon X, https://doi.org/10.1016/j.toxcx.2018.100003Question if rumen microflora might provide a protective shield for hepatotoxic effects of microcystin and nodularin? Cyanotoxins incubated with rumen fluid at three different concentrations (0.05, 0.5 and 5 ug/mL) for 3 hours in vitro. Concentrations were chosen to correspond to the subchronic and acute doses of cattle suggested by the California EPA (2012). Toxins analyzed by LC-MS (ESI) positive mode. Degradation efficiency was MC-YR 36%, nodularin 35%, MC-RR 25% and MC-LR 8.9% at a concentration of 0.05 ug/mL, which decreasing degradation at 0.5 ug/mL, and no degradation at 5 ug/mL. Little degradation observed after 3 hours up to 8 hours for MC-RR and MC-YR at the lowest concentration. [Note that MC-LR had rapid absorption from the gastrointestinal tract and metabolism of the parent compound within 1 – 2 hours after oral administration in rat.[Ref. 40, Kracko, D et al. SOT (2043 Poster Board-634) Washington DC, 2011] In vitro biodegradation of cyanotoxins in the rumen fluid of cattle. Manubolu M, Madawala S, et al. BMC Veterinary Research 2014,10:110. http://www.biomedcentral.com/1746-6148/10/110
Anatoxin-a toxicosis in dogs in North America
Anatoxins can be produced by many cyanobacteria
including Anabaena (Dolichospermum),
Oscillatoria, Planktothrix, Microcystis,
Aphanizomenon, Woronichinia, Cylindrospermum,
Phormidium.
Anatoxin-a can cause acute neurological signs of
muscle fasciculations, seizures, collapse, cyanosis
and death.
Clinical signs occurred within 5 to 60 minutes post
exposure to the water (swimming). Death is rapid,
usually with non-specific lesions on post-mortem.
Treatment of little or no benefit.
Differential diagnosis of toxicants important.
Challenge to obtain accurate microscopic
identification; need to detect toxins.
The water and stomach contents from these dogs
were positive for anatoxin-a by LC-MS/MS/MS
(CAHFS, UC Davis).
Puschner B, et al. J Vet Diagn Invest 2008;20:89-92. “Obi”, Photo courtesy of K. Benson, NDSU-VDLSummary of Cyanotoxins produced by Cyanobacteria or Harmful Blue-green Algae in upper Midwest
Toxin Target Organ in Cyanobacteria
Mammals
Cyclic peptide toxins
Microcystins Liver Microcystis, Anabaena
(Dolichospermum),
Planktothrix
(Oscillatoria),
Aphanizomenon
Nodularin Liver Nodularia
Alkaloids
Anatoxin-a Nervous system Anabaena
(Dolichospermum),
Planktothrix
(Oscillatoria),
Aphanizomenon,
Cylindrospermum
Anatoxin-a(S) Nervous system Anabaena
(Dolichospermum)
Cylindrospermopsins Liver Cylindrospermum
Anabaena
(Dolichospermum),
Aphanizomenon
Saxitoxins Nervous system Anabaena
(Dolichospermum)
Cylindrospermum
Aphanizomenon
Data adapted from:
EPA. Cyanobacteria and cyanotoxins: Information for drinking water systems. 2014.
Sivonen, K. and Jones G. Chapter 3. Cyanobacterial toxins. In: Chorus I. and Bartram J., eds: Toxic Cyanobacteria in Water: A guide to
their public health consequences, monitoring and management. E & FN Spon: London, UK. ©1999 WHOOften the next question after
identifying a cyanobacterial
bloom - is how can the livestock
producer use the water source for
potable livestock water.
An old-timers approach was to place barley straw in the
water source prior to hot weather to prevent a bloom.
(Photos courtesy of Dr. S. Ensley, K-State)
Livestock producers mention the use of algaecides,
particularly adding copper sulfate to the water source
and lyse the cyanobacteria that has many disadvantages.Side effects reported after numerous copper sulfate treatments in upper Midwest lakes 1) Intended temporary killing of algae with recovery of algal population within 7 to 21 days post treatment – so very ineffective. Repeat blooms could be more severe 2) Accelerated phosphorus recycling from the lakebed 3) Fish kills 4) Copper accumulation in the sediments that may render the water source unusable for sheep 5) Depletion of dissolved oxygen by decomposition of dead algae 6) Tolerance adjustments of certain algae to higher copper sulfate doses 7) Shift of species from green to harmful blue-green algae and from game fish to rough fish 8) Disappearance of macrophytes or large aquatic plants and benthic macroinvertebrates 9) Accumulation of cyanotoxins in algal mats for maybe 4 to 6 weeks and risks of animal exposure Hanson M.J., Stefan H.G. Side effects of 58 years of copper sulfate treatment of the Fairmont Lakes, Minnesota. Journal American Water Resources Association. Vol 20, 1984. https://doi.org/10.1111/j/1752-1688.1984.tb04797.x
Needs:
Improve obtaining water sampling from areas of
concern for livestock exposures.
Microscopic identification is not consistent, and
needs to be accompanied by a determination if
cyanobacteria are toxigenic or--
Consider the use of quick, low-cost tests for
multiple cyanotoxins.
The long-term answer may include establishment
of a riparian zone around water sources and
preventing livestock urine/fecal discharge into the
water source.
The use of aerators or ‘bubblers’ can agitate a
water source, but electricity or a power source is
needed for pasture use.
Microcystis bloom near Streeter North Dakota, Dr. K. Sedivec, NDSUYou can also read
