Paralytic shellfish poisonings resulting from an algal bloom in Nicaragua.

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.

Discrepancy, coincidence or evidence in chronic idiopathic spastic paraparesis throughout the world: a meta-analysis on 2811 patients

HTLV-I has been associated with a chronic idiopatic spastic paraparesis (CHISPA) in man; however, a complete undestanding of this association is still debated. We selected the most comprehensible papers on this topic between 1985 and 1996, and found that 1261 out of 2811 patients (44.9 percent) reported, throughout the world, were HTLV-I positive. The mean age was 39.5 years and there was a female predominance of 1.9:1. These results do not exclude the causality of HTLV-I as a germen associated to CHISPA; however, other causes) e.g., toxic, immunosuppressors) must be considered as participating in the multistep neurodegeneration observed in CHISPA throughout the world.