MercoPress. South Atlantic News Agency

With spring bloom come El Niño and deadly algae

Chilean investigators warned this week that temperatures in Chile's coastal waters have increased by half a degree since August, setting the stage for the arrival of “El Niño” by the end of this year.

El Niño is a warm ocean current that periodically, capriciously, moves in close to shore. It can be nasty, endangering human health and life and dealing devastating blows to the Chile's shellfish industry.

El Niño exacerbates what swimmers call the Red Tide and ocean scientists call HAB, for Harmful Algae Bloom. When certain marine shellfish eat HAB, toxins, poisonous to humans, build up in the sea creatures' flesh. These toxins have two bad consequences: Diarrheic Shellfish Poisoning (DSB) and Paralytic Shellfish Poisoning (PSP). The end effect on a human eating these infected shellfish will depend on the type and concentration of the toxins and the vulnerability of the human: it will range from misery to death.

Of the two types of toxins, PSP is the better known and by far the scarier. Early symptoms, which may appear within minutes of eating the tainted shellfish or may take an hour or two, include tingling lips and tongue. Symptoms may progress to tingling in the fingers and toes, and loss of control of arms and legs. The next symptom is difficulty in breathing. Some people experience nausea and a sense of floating. If a person has consumed enough poison, the muscles of the chest and abdomen become paralyzed, and death can result in as little as two hours. There is no antidote for PSP, and the only treatment involves mechanical assistance in breathing.

While PSP has been around for a long time, DSB is a relative newcomer in the corpus of medical knowledge. It was first identified in the Netherlands the 1960s, and was reported soon after in the waters off the northwest coast of the United States. Its range is global. DSP is less dramatic than its cousin, PSP, but little is known of its cumulative effects if ingested in quantity over a period of years. DSP is of particular interest to researchers at the Universidad de Chile, as the toxic is endemic among Patagonian molluscs.

Symptoms of DSP include vomiting, nausea, diarrhoea and abdominal cramps. Severe cases may produce neurological damage characterized by headaches, confusion, coma and even death, although death is rare. Small children and the elderly are among the highest risk groups for shellfish poisoning, as are those already weakened by disease.

Some recent research on laboratory rats at Duke University in the U.S. suggests that DSP may cause permanent neural damage in the foetus when a pregnant mother ingests contaminated seafood. The Duke researchers injected three sets of pregnant rats with different levels of toxins, all below the 20 parts per million (PPM) considered safe for human consumption. All three doses produced offspring with neural damage.

Carlos Garcia, a medical researcher at Universidad de Chile, headed up a study group that recently published a warning that DSP represented a global threat to public health and the shellfish industry, and advocates increased monitoring of this toxin in Chilean waters.

Garcia and his colleagues, Paulo Pereira, Luis Valle and Nestor Lagos, conclude: "To perform quantitative analysis of DSP toxins in shellfish samples is a requirement, because DSP toxins are endemic in the Chilean molluscs of the southern regions, and although human symptoms of DSP appear relatively mild in comparison with the Paralytic Shellfish Poisoning (PSP), the necessity of monitoring the chronic effects of continued uptake of low doses of DSP toxins more closely is imperative, since DSP toxins have been described as potent tumour promoters."

By Johnny Baker The Santiago Times Source: Internet Medical Research Sites