Pago Pago, AMERICAN SAMOA — Samoa's Ministry of Health has announced 65 cases of dengue-like illness in its latest reporting period, from April 29 to May 5. This comes as RNZ Pacific is reporting that American Samoa's Department of Health is set to start spraying private schools as a preventive effort against dengue fever.

Health department spokesperson Aileen Solaita said private schools are being sprayed first because they are smaller than public schools.

She said students will learn online while spraying is underway.

In Samoa, the Ministry of Health says the dengue-like illness count remains high, and urges the public to heed advice on prevention.

Patients with dengue-like illnesses have not yet had laboratory confirmation of the dengue infection.

A dengue outbreak was declared in Samoa on April 19.

Recommended prevention measures include cleaning up and removing stagnant water sources around the house which are potential mosquito breeding sites, and wearing appropriate clothing and using mosquito nets and repellents to minimize bites.

Meanwhile, a new study investigates climate indicators and worldwide dengue incidence from 1990 to 2019.

The researchers identify a distinct indicator, the Indian Ocean basin-wide (IOBW) index, as representing the regional average of sea surface temperature anomalies in the tropical Indian Ocean.

"IOBW is closely associated with dengue epidemics for both the Northern and Southern hemispheres," the study said.

"The ability of IOBW to predict dengue incidence likely arises as a result of its effect on local temperature anomalies through teleconnections.

"These findings indicate that the IOBW index can potentially enhance the lead time for dengue forecasts, leading to better-planned and more impactful outbreak responses."

The report, published in the journal Science, said El Niño climate events influence the dynamics of dengue transmission globally because of their effects on mosquito breeding.

"However, there are gaps in our understanding about long-distance climate drivers of dengue outbreaks.

"The findings of this study agree with prior research that identified local temperature variability as the primary driver of dengue epidemics.

"However, using a single temperature indicator makes it difficult to simultaneously predict the magnitude and timing of dengue epidemics in diverse countries owing to the different temperature variations across regions."

The US Centers for Disease Control and Prevention said almost half of the world's population, about 4 billion people, live in areas with a risk of dengue, and up to 400 million people get infected each year.

(Source: RNZ Pacific)