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Paralytic shellfish poisonings resulting from an algal bloom in Nicaragua.

Callejas L, Darce AC, Amador JJ, Conklin L, Gaffga N, Schurz Rogers H, DeGrasse S, Hall S, Earley M, Mei J, Rubin C, Aldighieri S, Backer LC, Azziz-Baumgartner E - BMC Res Notes (2015)

Bottom Line: PSP in humans is caused by ingestion of saxitoxin, which is a neurotoxin often associated with shellfish contaminated by algal blooms.The saxitoxin concentration in the urine of a hospitalized case-patient was 21 ng saxitoxin/g creatinine compared to 0.16 ng saxitoxin/g creatinine in the single control patient's urine.These findings suggest that a bloom of saxitoxin-producing algae resulted in saxitoxin accumulation in local clams and was responsible for the PSP intoxication.

View Article: PubMed Central - PubMed

Affiliation: Field Epidemiology Training Program, Managua, Nicaragua, USA. lcallejas@asamblea.gob.ni.

ABSTRACT

Background: During an October 2005 algal bloom (i.e., a rapid increase or accumulation in the population of algae) off the coast of Nicaragua, 45 people developed symptoms of paralytic shellfish poisoning (PSP) and one person died. PSP in humans is caused by ingestion of saxitoxin, which is a neurotoxin often associated with shellfish contaminated by algal blooms. To explore the relationship between the algal bloom and human illnesses, we performed a case-control study of residents living in a coastal island. We administered a standardized clinical questionnaire, sampled locally harvested seafood and algae, and obtained urine samples for saxitoxin testing from symptomatic and asymptomatic persons. PSP case-patients were defined as island residents who developed at least one neurological symptom during the November 4-16 intoxication period. Seafood and algal samples were analyzed for saxitoxins using the receptor-binding assay and high-performance liquid chromatography. Two urine samples were analyzed for saxitoxins using a newly developed immunoassay.

Findings: Three shellfish and two algal samples tested positive for saxitoxins. Ten (9%) of 107 participants developed neurological symptoms during the specified time period and five required hospitalization. While 6 (67%) of 9 possible case-patients and 21 (21%) of 98 controls had eaten fish (p=0.008), all case-patients and 17 (17%) of controls had eaten clams (P<0.0001). The saxitoxin concentration in the urine of a hospitalized case-patient was 21 ng saxitoxin/g creatinine compared to 0.16 ng saxitoxin/g creatinine in the single control patient's urine.

Conclusions: These findings suggest that a bloom of saxitoxin-producing algae resulted in saxitoxin accumulation in local clams and was responsible for the PSP intoxication.

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Related in: MedlinePlus

Pyrodinium bahamensein algal bloom water samples along the coast of Nicaragua, October-November, 2005.
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Fig1: Pyrodinium bahamensein algal bloom water samples along the coast of Nicaragua, October-November, 2005.

Mentions: In mid-October 2005, a local fisherman working near Corinto, a small town on the Pacific coast of Nicaragua, noticed a fluorescent greenish hue to the ocean water that significantly impaired underwater visibility (Figure 1). Within weeks, persons who experienced neurologic symptoms after eating seafood appeared in emergency rooms in and around Corinto. Seawater samples from the area contained 17.5 × 106 dinoflagellates per liter, almost twice the density needed to consider an algal bloom harmful [7]. Ninety-nine percent of these organisms were P. bahamanse, which is known to produce the saxitoxins that cause PSP.Figure 1


Paralytic shellfish poisonings resulting from an algal bloom in Nicaragua.

Callejas L, Darce AC, Amador JJ, Conklin L, Gaffga N, Schurz Rogers H, DeGrasse S, Hall S, Earley M, Mei J, Rubin C, Aldighieri S, Backer LC, Azziz-Baumgartner E - BMC Res Notes (2015)

Pyrodinium bahamensein algal bloom water samples along the coast of Nicaragua, October-November, 2005.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4359551&req=5

Fig1: Pyrodinium bahamensein algal bloom water samples along the coast of Nicaragua, October-November, 2005.
Mentions: In mid-October 2005, a local fisherman working near Corinto, a small town on the Pacific coast of Nicaragua, noticed a fluorescent greenish hue to the ocean water that significantly impaired underwater visibility (Figure 1). Within weeks, persons who experienced neurologic symptoms after eating seafood appeared in emergency rooms in and around Corinto. Seawater samples from the area contained 17.5 × 106 dinoflagellates per liter, almost twice the density needed to consider an algal bloom harmful [7]. Ninety-nine percent of these organisms were P. bahamanse, which is known to produce the saxitoxins that cause PSP.Figure 1

Bottom Line: PSP in humans is caused by ingestion of saxitoxin, which is a neurotoxin often associated with shellfish contaminated by algal blooms.The saxitoxin concentration in the urine of a hospitalized case-patient was 21 ng saxitoxin/g creatinine compared to 0.16 ng saxitoxin/g creatinine in the single control patient's urine.These findings suggest that a bloom of saxitoxin-producing algae resulted in saxitoxin accumulation in local clams and was responsible for the PSP intoxication.

View Article: PubMed Central - PubMed

Affiliation: Field Epidemiology Training Program, Managua, Nicaragua, USA. lcallejas@asamblea.gob.ni.

ABSTRACT

Background: During an October 2005 algal bloom (i.e., a rapid increase or accumulation in the population of algae) off the coast of Nicaragua, 45 people developed symptoms of paralytic shellfish poisoning (PSP) and one person died. PSP in humans is caused by ingestion of saxitoxin, which is a neurotoxin often associated with shellfish contaminated by algal blooms. To explore the relationship between the algal bloom and human illnesses, we performed a case-control study of residents living in a coastal island. We administered a standardized clinical questionnaire, sampled locally harvested seafood and algae, and obtained urine samples for saxitoxin testing from symptomatic and asymptomatic persons. PSP case-patients were defined as island residents who developed at least one neurological symptom during the November 4-16 intoxication period. Seafood and algal samples were analyzed for saxitoxins using the receptor-binding assay and high-performance liquid chromatography. Two urine samples were analyzed for saxitoxins using a newly developed immunoassay.

Findings: Three shellfish and two algal samples tested positive for saxitoxins. Ten (9%) of 107 participants developed neurological symptoms during the specified time period and five required hospitalization. While 6 (67%) of 9 possible case-patients and 21 (21%) of 98 controls had eaten fish (p=0.008), all case-patients and 17 (17%) of controls had eaten clams (P<0.0001). The saxitoxin concentration in the urine of a hospitalized case-patient was 21 ng saxitoxin/g creatinine compared to 0.16 ng saxitoxin/g creatinine in the single control patient's urine.

Conclusions: These findings suggest that a bloom of saxitoxin-producing algae resulted in saxitoxin accumulation in local clams and was responsible for the PSP intoxication.

Show MeSH
Related in: MedlinePlus