Strongy­loidi­a­sis often evades detec­tion, with dan­ger­ous con­se­quences. What about the dis­ease makes it easy to miss?

Strongy­loidi­a­sis doesn’t nec­es­sar­i­ly have spe­cif­ic symp­toms, and because Strongy­loides ster­co­ralis is micro­scop­ic, you won’t see it.

Being aware is vital, and hav­ing it in min­das a dif­fer­en­tial diag­no­sis. My jour­ney began by look­ing first at the unwell patient – with sep­ti­caemia or menin­gi­tis – and ask­ing why would a 25-year-old male be at risk of dying from septicaemia?

What’s the con­nec­tion between sep­ti­caemia and strongyloidiasis?

With strongy­loidi­a­sis, autoin­fec­tive filar­i­form lar­vae can trav­el from the bow­el and bur­row through the gut lining.

When they do this, they can also take with them bac­te­ria from the bow­el to any organ of the body. That’s where sep­ti­caemia and oth­er bac­te­r­i­al dis­eases can come in.

Dis­sem­i­nat­ed strongy­loidi­a­sis, the most advanced phase of the dis­ease, can also increase the risk of mul­ti­ple-end organ fail­ure and has a high fatal­i­ty rate. What pre­cip­i­tates it?

Peo­ple who are immuno­sup­pressed are at the great­est risk. In one study 65% of the fatal­i­ties from dis­sem­i­nat­ed strongy­loidi­a­sis were asso­ci­at­ed with giv­ing cor­ti­cos­teroids. The think­ing is that it has a dys­reg­u­la­tion effect. I see Strongy­loides ster­co­ralis in a David Atten­bor­ough way. It’s a sur­vival mech­a­nism. When the par­a­site sens­es that its home in the human is no longer safe, it says, ​“I need to find anoth­er home.” It starts mul­ti­ply­ing into its mil­lions, and the infec­tion becomes out of control.

What can health pro­fes­sion­als do to lim­it the risk of dis­sem­i­nat­ed strongyloidiasis?

Health pro­fes­sion­als work­ing in com­mu­ni­ty pri­ma­ry health­care ser­vices under­stand the val­ue of ear­ly diag­no­sis, treat­ment and fol­low-up test­ing, and are best placed to pre­vent clin­i­cal com­pli­ca­tions for strongyloidiasis.

The CARPA man­u­al rec­om­mends that any­one who is going to be immuno­sup­pressed needs to be test­ed for strongy­loidi­a­sis; but if they’re com­ing from a known endem­ic area, they also need to be giv­en iver­mectin treat­ment before they start their immunosuppressants.

The best way of find­ing and treat­ing peo­ple before they devel­op severe clin­i­cal com­pli­ca­tions is in the chron­ic phase and the best test for that is Strongy­loides serol­o­gy, though it may not detect new­ly acquired or dis­sem­i­nat­ed cas­es. This can be includ­ed with the adult health check/​preventative health assess­ment along with STIs, hepati­tis B, dia­betes, and chron­ic kid­ney dis­ease. Fol­low up serol­o­gy 6 to 12 months after treat­ment is rec­om­mend­ed as serol­o­gy decreas­es to neg­a­tive with effec­tive treat­ment. Some cas­es may require repeat treat­ment for eradication.

Iver­mectin should be giv­en to all pos­i­tive cas­es. We start­ed using iver­mectin in 2000 because it was more effec­tive for strongyloidiasis.

Before that I remem­ber alben­da­zole being intro­duced in 1995. That made a huge dif­fer­ence to a num­ber of oth­er helminths. But for S. ster­co­ralis, it’s not enough to reduce the worm load – you need to erad­i­cate each last worm due to its auto-infec­tive cycle.

Inter­na­tion­al guide­lines in the 1990s rec­om­mend­ed treat­ing all infect­ed per­sons, includ­ing the asymp­to­matic, as life threat­en­ing com­pli­ca­tions are unpredictable.

Strongy­loides serol­o­gy has been includ­ed in the Refugee Health Assess­ment since 2010 and those with pos­i­tive and equiv­o­cal results are treat­ed to pre­vent clin­i­cal com­pli­ca­tions and transmission.

By treat­ing the peo­ple that test pos­i­tive, you’re also pre­vent­ing trans­mis­sion, because it’s humans that will take it from one place to anoth­er – hence desert com­mu­ni­ties can have Strongy­loides as well. It is not some­thing that relates just to the tropics.

What advice can nurs­es give, and fol­low, when it comes to pre­vent­ing infection?

Patients want to know about Strongy­loides, what it is, where it lives, what makes it spe­cial, how it affects the body, how it can be diag­nosed and treat­ed, and how they can pre­vent it. 

We devel­oped the Strongy­loides patient edu­ca­tion flip chart in ear­ly 2002 and it is a very use­ful visu­al aid. It’s avail­able on the strongyaust​.au website.

Strongy­loides ster­co­ralis sur­vival out­side the body is lim­it­ed. It looks for a warm host and enters through the skin. Wear­ing shoes makes a dif­fer­ence – if you’re in an area where there is poten­tial for fae­cal con­t­a­m­i­na­tion. If you’re han­dling fae­ces at any point of time, that’s poten­tial­ly infectious. 

Per­sons with dis­sem­i­nat­ed strongy­loidi­a­sis are also infec­tious with cas­es diag­nosed from spu­tum or skin. Every­one will do their best to pre­vent it, but I am aware of clin­i­cians who have become infected.

How about pri­mor­dial prevention?

We see One Health as a way to address strongy­loidi­a­sis. One Health con­sid­ers humans as well as ani­mal health and envi­ron­men­tal health. At the envi­ron­men­tal lev­el, trans­mis­sion hap­pens when there’s inad­e­quate access to clean water and san­i­ta­tion – a basic human right and Unit­ed Nations Sus­tain­able Devel­op­ment Goal Num­ber 6.

We see hav­ing strongy­loidi­a­sis made noti­fi­able as a way to iden­ti­fy hotspots. The World Health Organ­i­sa­tion (WHO) has also now includ­ed strongy­loidi­a­sis with­in the neglect­ed trop­i­cal dis­eases for elim­i­na­tion by 2030.

Do you think that can be done?

Aus­tralia needs to start act­ing. Dis­mis­sive com­ments like ​“why both­er to treat the asymp­to­matic” or ​“they’ll only get it again” have always upset me. Aus­tralia could be lead­ing the way in how we address this – because we can do some­thing, just like Miwatj has. We need to look at this as a chron­ic infec­tious dis­ease that is treat­able and cur­able if diag­nosed early.

The sys­tem­at­ic approach of includ­ing strongy­loidi­a­sis in a pre­ven­ta­tive health assess­ment is vital for all endem­i­cal­ly infect­ed com­mu­ni­ties in Aus­tralia. Oth­er­wise, con­trol­ling this dis­ease is depen­dent on indi­vid­u­als, and indi­vid­u­als come and go.

Con­trol pro­grams in endem­ic com­mu­ni­ties are fea­si­ble – your work has pro­duced reduc­tions as dra­mat­ic as 60 to 10 per cent prevalence.

10 per cent is cer­tain­ly a reduc­tion, but still 10 times what you would expect in a sub­urb of Bris­bane. My focus is on clos­ing that gap.

By iden­ti­fy­ing strongy­loidi­a­sis, we’re also iden­ti­fy­ing the com­mu­ni­ties that are at the great­est risk for oth­er dis­eases, and in great­est need of fur­ther infra­struc­ture – for exam­ple, hous­ing and san­i­ta­tion facil­i­ties. It’s a proxy for reduc­ing oth­er con­di­tions you don’t expect to have in Australia.

Your pas­sion is inspir­ing. What has moti­vat­ed you to take on strongy­loidi­a­sis and what has kept you going?

My strongy­loidi­a­sis jour­ney began in 1995, with a par­a­sitol­ogy course and Rick Speare being a fan­tas­tic men­tor. Cas­es of dis­sem­i­nat­ed strongy­loidi­a­sis were unfold­ing around this time, then in 1999, my col­league, friend and men­tor, an Abo­rig­i­nal Health Work­er who was a queen for her peo­ple, devel­oped a con­di­tion and went to Dar­win. Instead of being able to come back and have that man­aged at home, she died in Ade­laide from dis­sem­i­nat­ed strongy­loidi­a­sis. It was a huge loss. It becomes per­son­al when it is some­one you know.

In 2000 we intro­duced iver­mectin, which made a big dif­fer­ence. When I was speak­ing to her sis­ter and explain­ing what we were doing, she said to me, ​“let not her death be in vain”.

When you’re the com­mu­ni­ty doc­tor, you learn about what is rel­e­vant in your com­mu­ni­ty. There were times I could have walked away, but I felt I had been giv­en this respon­si­bil­i­ty to take fur­ther for­ward. And I wasn’t on my own.