Don’t fall fowl of this in­fec­tion

Campy­lobac­ter is nasty and poul­try is the most com­mon source of in­fec­tion. Pro­tect your­selves, write Nigel French and Glenda Lewis.

The Timaru Herald - - CATALYST -

It’s not just about water. Mem­bers of the NZ and in­ter­na­tional water as­so­ci­a­tions are meet­ing in Hamil­ton this week to un­pick what hap­pened in Have­lock North to cause the world’s worst recorded water-borne out­break of campy­lobac­ter in­fec­tion.

A year ago, the aquifer Have­lock North draws on was con­tam­i­nated with fae­cal mat­ter from sheep fol­low­ing heavy rain.

A guest speaker at the meet­ing is Steve Hrudey from the Univer­sity of Al­berta, who will re­count the anal­o­gous ex­pe­ri­ences of Walk­er­ton, On­tario, where, in May 2000, sev­eral thou­sand peo­ple be­came ill from con­tam­i­na­tion of their water sup­ply with harm­ful strains of E coli, and campy­lobac­ter. Seven died.

The out­break in Have­lock North showed New Zealan­ders just how nasty campy­lobac­ter in­fec­tion can be, es­pe­cially for the el­derly and peo­ple with com­pro­mised im­mune sys­tems. The deaths of two, and pos­si­bly three, peo­ple were linked to this out­break, and three were hos­pi­talised with the paralysing neu­ro­log­i­cal dis­or­der, Guil­lainBarre syn­drome. Some of the con­se­quences do not ap­pear in black and white sta­tis­tics. For ex­am­ple, one el­derly woman who was manag­ing well liv­ing in her own home had to go into a rest home fol­low­ing in­fec­tion. For her it was life-chang­ing.

The Have­lock North in­ci­dent landed us in the global in­fec­tious disease record books. Hope­fully the lessons will be taken. There’s a clear need to en­sure that all our drink­ing water sup­plies are ad­e­quately pro­tected, us­ing wellestab­lished and safe meth­ods such as chlo­ri­na­tion.

New Zealand has one of the high­est rates of re­ported campy­lobac­ter in­fec­tions among OECD coun­tries, and much of this is food-borne. About 6000-7000 cases are re­ported each year, com­pared to just over 1000 cases of sal­mo­nella, and it is es­ti­mated that a fur­ther 25,000 cases go un­re­ported. Typ­i­cally, vic­tims suf­fer about a week of de­bil­i­tat­ing gas­troen­teri­tis, and need a week off work or school. For some, this is a week with no in­come. This all adds to a sig­nif­i­cant eco­nomic deficit na­tion­ally.

Rates of in­fec­tion started to rise markedly in the early 1990s, track­ing the rise in con­sump­tion of fresh chilled, not frozen, chicken. The rate peaked in 2006, when New Zealand was wryly re­ferred to by in­ter­na­tional food safety ex­perts as ‘‘campy­lobac­ter cap­i­tal of the world’’.

Di­rec­tor of the NZ Food Safety Sci­ence & Re­search Cen­tre (NZFSSRC), Pro­fes­sor Nigel French, and his lab team at Massey Univer­sity, worked with the In­sti­tute of En­vi­ron­men­tal Sci­ences and Re­search (ESR) and the New Zealand Food Safety Author­ity (now MPI), to trace the ori­gin of in­fec­tions us­ing new ge­netic foren­sic tech­nolo­gies.

They con­firmed that poul­try was by far the most com­mon source of in­fec­tion. Af­ter reg­u­la­tory con­trols de­vel­oped by MPI and vol­un­tary in­dus­try con­trols were im­ple­mented, re­ported cases im­me­di­ately re­duced by more than half (from a peak of over 380 per 100,000 of pop­u­la­tion to 161 per 100,000).

But the av­er­age level has not re­duced fur­ther since then, and poul­try is still es­ti­mated to be a ma­jor con­trib­u­tor to campy­lobac­ter in­fec­tions in New Zealand, par­tic­u­larly in ur­ban ar­eas.

Like E coli, campy­lobac­ter bac­te­ria are com­mon in the gut and fae­ces of many an­i­mals. Hu­mans can be ex­posed to campy­lobac­ter from con­tam­i­nated water (in­clud­ing rivers), raw meat, raw milk and con­tam­i­nated sur­faces . Heat­ing above 75 de­grees Cel­sius will kill th­ese pathogens in poul­try, red meat and milk. Phys­i­cal con­tact with an­i­mals is also a sig­nif­i­cant path­way for in­fec­tion.

Elim­i­nat­ing campy­lobac­ter from the poul­try pro­cess­ing chain has proven very dif­fi­cult in many coun­tries, in­clud­ing New Zealand. Even though chick­ens are pro­cessed in a way that elim­i­nates most campy­lobac­ter by the end of pro­cess­ing, the bac­te­ria are still com­monly found on the sur­face of raw chicken meat and the juices around it, and in num­bers suf­fi­cient to cause ill­ness. Campy­lobac­ter is a sur­vivor! At a re­cent meet­ing of food sci­en­tists in Nel­son, Pro­fes­sor Arnoud van Vliet of the Univer­sity of Sur­rey, called campy­lobac­ter ‘‘Europe’s new su­per­bug’’.

He re­ported high lev­els of campy­lobac­ter in fresh chicken packs sold in rep­utable Bri­tish su­per­mar­kets. Campy­lobac­ter was present in be­tween 64 per cent and 78 per cent of the sam­ple sur­veyed.

Ge­netic sequencing has made it pos­si­ble to track the evo­lu­tion of fast-chang­ing bac­te­ria, and iden­tify the sources of in­fec­tion with pre­ci­sion. The at­tri­bu­tion of the Have­lock North out­break to sheep fae­ces was in­con­tro­vert­ible. Know­ing the source af­ter the event is not much com­fort to the af­flicted, how­ever. As al­ways, preven­tion is bet­ter than cure.

A new con­cern with campy­lobac­ter is the emer­gence in 2014 of a strain that is re­sis­tant to two an­tibi­otics – tetra­cy­cline and flu­o­ro­quinolone. A sur­vey con­ducted in 2015 found that this strain was preva­lent in poul­try in the North Is­land and had be­come the most com­mon in hu­man campy­lobac­ter in­fec­tions.

This is un­usual for NZ, where we have his­tor­i­cally ex­pe­ri­enced very low lev­els of an­tibi­otic re­sis­tance in campy­lobac­ter. For­tu­nately, an­tibi­otic treat­ment is not usu­ally re­quired for campy­lobac­ter in­fec­tion but if it is, ery­thromycin is usu­ally the drug of choice. To date, there is no ev­i­dence of wide­spread re­sis­tance to this an­tibi­otic in New Zealand.

The NZ Food Safety Sci­ence & Re­search Cen­tre ad­vises you to fol­low the rules if you want to con­tinue en­joy­ing your roast and but­ter chicken. We strongly ad­vise against eat­ing raw chicken as sashimi.

Mean­while, NZFSSRC sci­en­tists around New Zealand

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