The Division of Water Quality (DWQ) was notified by the Utah County Health Department on Monday, October 6, 2014, that a dog had died over the weekend after swimming and consuming water near the Lindon Marina on Utah Lake. Algal blooms in the lake are the suspected source of the toxic cyanobacteria that may be responsible for the dog’s death.
Although algae are a natural part of many freshwater ecosystems, under the right conditions they can proliferate to create large algal blooms. These blooms can contain harmful cyanobacteria, a type of photosynthetic bacteria (often referred to as blue-green algae) that produce toxins that can pose risks to humans, wildlife, domestic animals, and fish. Elevated levels of nutrients in the water, combined with increased temperatures and calm water, can promote rapid algal growth, resulting in extensive, bright-green blooms that can last for days or weeks.
DWQ is conducting ongoing, comprehensive sampling and monitoring of the lake and downstream areas to determine the extent of the possible cyanotoxin contamination of these waters. Sampling is critical, since the only way to know if a cyanobacteria bloom is harmful is to test for the presence of toxins in the water. In addition, cyanotoxins can remain in the water once the algal bloom has dissipated, which underscores the importance of continued sampling and monitoring to confirm the presence or absence of these toxins after the bloom subsides.
The Division is coordinating with the Utah County Health Department, Utah State Parks and Recreation, and Division of Wildlife Resources (DWR) on sampling and results to allow these entities to move forward on public-health advisories, if necessary, for the affected areas.
Update: January 28, 2015
The preliminary necropsy report for the dog that died shortly after drinking the water on October 5, 2014, from Utah Lake has been finalized. A specific cause of death was not identified. The Utah Veterinary Diagnostic Laboratory concluded that cyanobacteria toxins were an unlikely cause of death because no cyanobacteria or cyanotoxins were detected in the stomach contents or liver of the animal. Specifically, the necropsy report states the following (details are available in the full report linked at the bottom of this post):
“Only one of three heart measurement ratios used to indicate right ventricular hypertrophy is elevated, but overall gross cardiac changes argue that hypertrophy is indeed present. Moreover, the ratio of aortic to pulmonic valve circumferences is consistent with pulmonic valve dilation. Pulmonic valve dilation results in valvular leakage with volume overload to the right ventricle, which over time produces compensatory hypertrophy. Pulmonic valve dilation can be a congenital malformation or secondary to pulmonary hypertension or valvular infections (not identified here). Given the age of this animal, a congenital anomaly is likely. Other causes (among many) of acute cardiovascular collapse include a variety of toxicants (botulism, blue-green algae, carbamates, cyanide, nitrites/nitrates, organophosphates, strychnine, water hemlock, etc.), electric, anaphylactic or other forms of shock and grand mal epileptic or other seizures. Blue-green algae is not identified in gastric contents and Anatoxin-a and microcystin toxins are not identified chemically, making blue-green algae toxicity highly unlikely.”
As stated above, the examining veterinarian concluded that it was highly unlikely that blue green algae were responsible for the dog’s death.
Since the report of the dog death on October 5, 2014, DWQ scientists have investigated reports of another dog that died within hours of being in Utah Lake on October 4, 2015. Based on the information provided by the owner, this dog was in the water on the west side of Utah Lake. The dog began showing symptoms of distress shortly after being in the lake and was taken to an emergency clinic. The dog died at the clinic. The veterinarian concluded that ingestion of cyanobacteria was the cause of death was based on:
- the dog’s symptoms and rapid death
- the veterinarian’s past experience with cyanotoxin poisonings in another state
- the dog being recently at the lake
- cyanobacteria present on the dog’s nose
The veterinarian also observed that some of the symptoms were neurological. This dog was cremated, so no further analyses could be done.
Despite the lack of confirmation that cyanobacteria poisoning was the cause of the death for the dog that died on October 5, 2014, DWQ and Utah Department of Health scientists still suspect cyanobacteria as the sole or a contributing cause of death for both dogs. Both dogs died within hours of being in the water where toxin-producing cyanobacteria were present. The symptoms exhibited were consistent with cyanotoxin poisoning, specifically neurotoxins. Even though cyanobacteria were not detected in the dog’s stomach during necropsy, the dog’s owner reported that the dog was drinking the water where “algae” had accumulated and vomited bright green “algae.” Cyanotoxins were not detected in the tissues of the necropsied dog, but the analytical methods that were used only identify a limited number of the known cyanotoxins, and additional unidentified toxins are suspected to exist.
Negative results from the toxin analyses are not uncommon in dog deaths attributed to cyanotoxin poisonings. Other causes not related to cyanobacteria are plausible as the cause of one or both of the deaths, but these were judged to be less likely given the weight of environmental evidence and that two dogs died within 24 hours of one another after ingesting Utah Lake water.
The Utah Division of Wildlife Resources (DWR) gathered dead waterfowl from Utah Lake for laboratory testing. DWR submitted five birds collected from areas where blue-green algae were present (Lindon Harbor down to Provo Bay) to the lab for analysis. Anatoxin-a test results came back negative. Additionally, there were no hepatic (liver) lesions to support microcystin exposure, so the laboratory has ruled out cyanobacteria poisoning. DWR suspects that these waterfowl deaths may be due to botulism type C.
- Utah Veterinary Diagnostic Lab Final Report
- California Animal Health Lab Analysis of Stomach Contents
Update: October 30, 2014
DWQ has received the test results from the cyanotoxin analysis conducted on samples collected October 22, 2014. Lab results show that microcystin levels remain below World Health Organization (WHO) guidelines. Cylindrospermopsin and Anatoxin-a were not detected. While the cooling weather has helped reduce the bloom, there may still be accumulations of cyanobacteria along the shorelines that could pose a health threat until they are “cleaned” through wave action.
The Utah County Health Department urges the public to continue to take appropriate precautions at the lake. Health officials suggest:
- People and pets should still stay out of areas with visible algae.
- People and pets should not drink the water and avoid getting water in their mouths.
- Individuals who recreate on Utah Lake should wash their hands and face after being in the lake and especially before eating.
Update: October 21, 2014
The Utah Department of Environmental Quality has determined the harbor water is contaminated by a toxic algae which is strongly suspected to have killed dogs and is known to be dangerous to humans. By order of the Utah County Health Department, the harbor is closed to swimming and bathing for humans and animals.
Update: October 20, 2014
Results from water samples collected at Utah Lake on October 10, 2014, show that while concentrations of microcystins had dropped in most locations, samples taken from cyanobacteria that had accumulated along the Lindon Harbor shoreline on October 10th showed a value of 730 micrograms per liter (ug/L) for microcystins.
The level of microcystins found along the shoreline—over 70 times the health advisory level—has a high probability of producing acute health effects during recreational exposure according to health-based guidelines established by the Environmental Protection Agency (EPA) and World Health Organization (WHO).
These data highlight how variable toxin concentrations can be within a small area. Earlier sampling results were more broadly representative of microcystin levels within the harbor area, and other samples taken on October 10, 2014, showed that the concentrations of microcystins had dipped below levels that could trigger a public health advisory. The sampling results from the shoreline, however, suggest that earlier data may not have been representative of the water that was ingested by the dog.
A public health advisory remains in effect for Utah Lake, and the Utah County Health Department recommends that people and animals refrain from swimming or ingesting water in areas with algal blooms to avoid exposure to possible toxins.
Update: October 14, 2014
DWQ has received the preliminary results of the necropsy (autopsy) for a dog that died shortly after drinking water from Utah Lake containing blue-green algae, or cyanobacteria. According to the report, the animal died from acute cardiovascular collapse consistent with exposure to a neurotoxin.
Microcystin and cylindrospermopsin, the cyanotoxins that were detected in the Utah Lake samples, are liver toxins (hepatotoxins). The necropsy report found only minor damage to the dog’s liver. Obvious liver damage is a characteristic of poisoning by microcystin or cylindrospermopsin.
Aphanizomenon, one of the three genera of cyanobacteria identified in the water samples taken from Utah Lake, produces a potent neurotoxin known as anatoxin-a. This cyanotoxin was originally known as Very Fast Death Factor (VFDF) because animals exposed to anatoxin-a often died within a matter of minutes or hours. The rapid death of the dog after drinking the water and the cause of death are consistent with neurotoxin exposure. The presence in the lake water of a cyanobacterium known to be capable of producing neurotoxins also points to possible anatoxin poisoning.
While testing on the samples taken on Monday, October 6, 2014, did not detect anatoxin-a, this particular cyanotoxin degrades readily, having an environmental half-life of twenty-four hours. It is possible that anatoxin-a, unlike the more persistent microcystin, had degraded by the time the samples were taken one day later.
Water samples from Utah Lake were tested using enzyme–linked immunosorbent assays (ELISA), the most commonly used rapid method to test for cyanotoxins. Anatoxin-a analysis requires the use of high performance liquid chromatographic (HPLC) methods that take longer than ELISA. Other neurotoxins produced by cyanobacteria that are similar to anatoxin-a in composition (analogues) and toxicity do not currently have standard measurement methods. It is possible that anatoxin-a analogues were present but not detected due to the testing methods used.
Tissue samples from the dog were sent for analysis to the California Animal Health and Food Safety (CAHFS) laboratory in Davis, California. This analysis may help determine whether anatoxin-a was responsible for the dog’s death.
See the DWQ memorandum for more detailed information.
Update October 10, 2014
Results from the samples collected on Wednesday indicate that the concentrations of the toxin are dropping, with all measurementsnow below the thresholds used by other states to trigger public health advisories. Based on these results, DWQ decided not to conduct additional monitoring over the weekend. The division will reevaluate the bloom early next week to determine if additional monitoring is warranted.
Update: October 9, 2014 (P.M.)
Microcystin, which can cause liver damage, was detected at 11 micrograms per liter (ug/L) from a water sample collected from the north side of the Lindon Harbor jetty on October 6, 2014. Another sample collected at the same time from the south side of the jetty had a microcystin concentration of 4.5 ug/L.
For comparison purposes, public health advisory levels have been set at 6 ug/L in Washington, Ohio, Virginia, and Vermont; 10 ug/L in Oregon; and 14 ug/L in Massachusetts. Each state uses different factors, such as body weight and rate of ingestion, in their calculations, which accounts for the range of values in these advisory levels. Utah does not currently have a public health advisory level for cyanotoxins.
For further information, see the Press Release.
Update: October 9, 2014 (A.M.)
Utah County Health Department officials have issued a warning to anyone swimming or boating on Utah Lake to avoid areas of bright green algae growth. Owners should also keep their dogs out of these areas.
The Utah Division of Wildlife Resources (DWR) is advising anglers and hunters to avoid these areas and not eat fish, shellfish, birds, or other animals that are found dead or sick. DWR recommends that anglers catching fish on Utah Lake during the algal bloom remove the fat, skin and organs from the fish before cooking, being particularly careful to not to cut into the organs. Before cooking or freezing the fish, the fillets should be rinsed with clean water to remove any contaminants that may have gotten onto the fillets during the cleaning process.
Update October 8, 2014
Sampling continued today at the Lindon Boat Harbor, Provo State Park Harbor, the Jordan River at the Utah Lake Outlet, and Jordan River at the Narrows. DWQ collected samples for the following constituents:
- Total Chemistry
- Non-Filtered Nutrients
- Filtered Nutrients
- Filtered Metals
- Field Parameters
Update: October 6, 2014
DWQ environmental scientists, in collaboration with scientists specializing in aquatic algal analysis, conducted both visual observations of the lake and collected multiple algae samples of the blooms observed near the marina. Samples were sent to a Florida lab for analysis to determine if the three dominant genera of cyanobacteria comprising this bloom—Microcystis, Aphanizomenon, and Dolichospermum—were producing cyanotoxins.