{"id":156317,"date":"2022-03-13T08:00:24","date_gmt":"2022-03-13T18:00:24","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=156317"},"modified":"2022-06-17T12:44:50","modified_gmt":"2022-06-17T22:44:50","slug":"ala-wai-infectious-bacteria","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2022\/03\/13\/ala-wai-infectious-bacteria\/","title":{"rendered":"Spikes in Ala Wai infectious bacteria influenced by rainfall"},"content":{"rendered":"Reading time: <\/span> 3<\/span> minutes<\/span><\/span>
\"man
Senior author Grieg Steward collecting samples from Ala Wai Canal. (Photo credit: SOEST<\/abbr>)<\/figcaption><\/figure>\n

In the Ala Wai Canal in Waikīkī, the abundance of Vibrio vulnificus<\/em>, an infectious bacterium, is strongly influenced by the amount of rainfall in the surrounding areas, according to a published study<\/a> by oceanographers at the University of Hawaiʻi<\/span> at Mānoa and Hawaiʻi<\/span> Pacific University (HPU<\/abbr>).<\/p>\n

Study authors Olivia Nigro<\/strong>, a former graduate student in oceanography at 糖心Vlog官方<\/abbr> Mānoa and now an assistant professor at HPU<\/abbr>, and Grieg Steward<\/strong>, professor in the 糖心Vlog官方<\/abbr> Mānoa School of Ocean and Earth Science and Technology<\/a>, first assessed Vibrio in 2006, when an Oʻahu<\/span> man died from a V. vulnificus<\/em> infection after his cuts and scrapes were exposed to Ala Wai Harbor water.<\/p>\n

\"woman
Lead author Olivia Nigro collecting samples from Ala Wai Canal.<\/figcaption><\/figure>\n

“His exposure occurred after many days of heavy rainfall, which, given our results, suggests this may have been an exacerbating factor,” said Steward. “At the time, we realized there was almost no data on the ecology of V. vulnificus<\/em> in the canal, or in Hawaiʻi<\/span> generally, and remarkably, very little in tropical waters anywhere.”<\/p>\n

After a quick pilot study in 2006 that showed the bacteria are present in high, but not unexpected numbers, the team geared up for a year-long study in 2008–09 with better methods to understand the variability in abundance over a seasonal cycle.<\/p>\n

Hawaiʻi\u2019s<\/span> unique dynamics<\/h2>\n

At higher latitudes, the abundance of V. vulnificus<\/em> shows a very strong seasonal cycle—nearly disappearing in winter when temperatures are cold. In Hawaiʻi<\/span>, temperatures are warm year-round, so freshwater input becomes a more important control.<\/p>\n

“V. vulnificus<\/em> occurs naturally in warm, brackish waters,” said Nigro. “So we expect to find this bacterium anywhere that temperatures are warm and freshwater and seawater mix in about equal proportions. When conditions are right, the Ala Wai Canal can be a great incubator for this bacterium!”<\/p>\n

The researchers observed that rainfall has a variable effect depending on the amount of precipitation.<\/p>\n

“Too little rainfall means much of the canal is saltier than optimum for V. vulnificus<\/em> growth, too much rainfall and the canal is fresher than the bacterium likes,” said Nigro. “We also found that, because of the flushing effect of intense rainfall, the highest abundance of V. vulnificus<\/em> shifted from within the canal out into the harbor.”<\/p>\n

\"heavy
Ala Wai Canal during heavy rain. (Photo credit: Grieg Steward, SOEST<\/abbr>)<\/figcaption><\/figure>\n

They observed the highest canal-wide average abundances, among the highest recorded anywhere, during a time of modest rainfall, moderate salinities and a moderate flushing of the canal.<\/p>\n

The researchers noted that, although rainfall is more frequent in winter on average, significant rainfall can also occur in summer, so spikes in V. vulnificus<\/em> can be a problem any time of year. This makes it challenging to predict precisely when and where there will be high concentrations of this pathogen. However, based on a few variables—rainfall and resulting salinity and flushing of the canal—the relative risk of exposure to this pathogen could be predicted as an average for the system.<\/p>\n

Reducing the risk of infection<\/h2>\n

With additional years of data to better understand how V. vulnificus<\/em> varies in space and time, it may be possible to provide real-time predictions of when and where the bacterium is likely to be at unusually high concentrations, which is one component in assessing the risk of infection.<\/p>\n

“Although V. vulnificus<\/em> can cause serious or even lethal infections, it usually only becomes a problem for individuals with underlying medical issues,” said Steward. “So people should not panic about incidental exposure to canal water. But it is wise to wash off with soap and water after exposure and one should avoid exposing open wounds to canal water, especially if one is immunocompromised.”<\/p>\n

This project was supported by funding from the National Oceanic and Atmospheric Administration through Hawaiʻi<\/span> Sea Grant<\/a> and from the National Science Foundation.<\/p>\n

This work is an example of 糖心Vlog官方<\/abbr> Mānoa\u2019s goal of Excellence in Research: Advancing the Research and Creative Work Enterprise<\/a> (PDF<\/abbr><\/span>), one of four goals identified in the 2015–25 Strategic Plan<\/a> (PDF<\/abbr><\/span>), updated in December 2020.<\/p>\n

–By Marcie Grabowski<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

In the Ala Wai Canal in Waikīkī, the abundance of Vibrio vulnificus<\/em>, an infectious bacterium, is strongly influenced by the amount of rainfall in the surrounding areas.<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[1467,1363,107,158,92,9,438],"class_list":["post-156317","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research","tag-manoa-excellence-in-research","tag-manoa-research","tag-oceanography","tag-publication","tag-school-of-ocean-and-earth-science-and-technology","tag-uh-manoa","tag-uh-sea-grant","entry","has-media"],"aioseo_notices":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/156317","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/comments?post=156317"}],"version-history":[{"count":11,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/156317\/revisions"}],"predecessor-version":[{"id":160859,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/posts\/156317\/revisions\/160859"}],"wp:attachment":[{"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/media?parent=156317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/categories?post=156317"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hawaii.edu\/news\/wp-json\/wp\/v2\/tags?post=156317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}