Travel clinic

Many of us fear snakes and spi­ders but dis­eases aris­ing from brushes with larger an­i­mals pose greater health risks, says Dr Jane Wil­son-howarth, un­less you know how to stay safe

Wanderlust Travel Magazine (UK) - - Contents -

Why you’ll never pet a street dog again! Dr Jane takes on zoonoses

‘In Nige­ria, I was sur­prised peo­ple talked so fondly of the de­lights of din­ing on wild bam­boo rats and even mon­keys and other pri­mates’

Some in­fec­tions car­ried by an­i­mals can be trans­ferred to hu­mans, and are of­ten dis­as­trous for those few of us who are un­lucky enough to catch them. Such dis­eases are re­splen­dent in the name zoonoses (pro­nounced zoo-no-sees), and once they have made the species leap, some can then spread be­tween hu­mans. The best known zoono­sis is vac­cinepre­ventable ra­bies, but there are, un­for­tu­nately, many more for which im­mu­ni­sa­tion is sim­ply not pos­si­ble.

An in­fec­tion is most likely to jump from one species to an­other when there is any kind of close con­tact. Amer­i­cans, for ex­am­ple, oc­ca­sion­ally catch bubonic plague from their cats (the cats hav­ing got too close to rats and their fleas).

It is per­haps un­sur­pris­ing that sev­eral of the most no­to­ri­ous out­breaks in re­cent years have come out of China, where those with lim­ited re­sources are forced to cram into small homes and have a habit of liv­ing with their live­stock, keep­ing chick­ens or pigs in, or very close to, their homes. Then, if one per­son be­comes in­fected, other fam­ily mem­bers may also be­come ill be­cause in­fec­tion spreads fastest in crowded con­di­tions.

NEW DIS­COV­ER­IES

SARS (Se­vere Acute Res­pi­ra­tory Syn­drome) was one in­fec­tion that came out of China. At one point it ap­peared to die out – suc­cess­fully con­trolled by quar­an­tin­ing those in­fected. But as re­cently as De­cem­ber 2017, sci­en­tists re­ported trac­ing SARS to a colony of bats in a re­mote cave in China, em­pha­sis­ing that an­other out­break is not im­pos­si­ble. Do­mes­tic an­i­mals (dogs and cats) that like to scav­enge flesh may per­haps visit such caves and be­come in­fected only to pass this on to their own­ers. South-east Asia has now been the source of sev­eral strains of in­fluenza orig­i­nat­ing from do­mes­tic pigs, poul­try or other birds.

The SARS dis­cov­ery is heart­en­ing as it shows that Chi­nese pub­lic health re­searchers are vig­i­lant to the pos­si­bil­ity of an­other killer pan­demic. The great chal­lenge of this mil­len­nium is mit­i­gat­ing the am­ple op­por­tu­ni­ties there are to share and spread dis­ease be­cause in­ter­con­ti­nen­tal travel is now so easy. Mean­while, Chi­nese sci­en­tists now have ma­te­rial to work on a vac­cine in case of an­other SARS out­break.

BUSH MEAT

Poverty of­ten drives peo­ple to­wards un­healthy choices, and it is thought that the source of the lat­est Ebola out­break in West Africa was due to eat­ing ‘bush meat’, prob­a­bly in the form of chim­panzees. When I was in Nige­ria in the sum­mer, I was sur­prised how peo­ple talked so fondly of the de­lights of din­ing on wild bam­boo rats and even mon­keys and other pri­mates. They felt that the Ebola cri­sis was over, so there was no longer any sig­nif­i­cant health risk in eat­ing wildlife.

How­ever, Ebola isn’t the only un­pleas­ant in­fec­tion con­tracted through eat­ing the

raw or poorly cooked meat of an un­healthy wild an­i­mal. Trav­ellers have ac­quired lep­rosy from un­der­cooked ar­madillo, and tu­laraemia could be a con­se­quence of eat­ing un­der­cooked hare or rab­bit. Tu­laraemia symp­toms can range from fever to skin ul­cers, but the pathogen is killed by be­ing heated to just 75ºc, so even light cook­ing ren­ders this wild meat safe. As ever, it is worth ad­her­ing to the ‘peel it, cook it, boil it or for­get it’ rule, es­pe­cially when eat­ing any­thing weird. In fact, vege­tar­i­ans will likely stay health­ier than meat eaters where in­fec­tions and par­a­sites are abun­dant.

OF MICE AND MEN

In a sim­i­lar vein, it is a wise idea to be alert to the state of the en­vi­ron­men­tal hy­giene of your ac­com­mo­da­tion, as well as any restau­rant that you are

us­ing. In the last doc­u­mented out­break of han­tavirus – an in­fec­tion car­ried by ro­dents that can lead, in some cases, to pul­monary com­pli­ca­tions – the source of the cases in Yosemite Na­tional Park was traced to deer mice. Some 12% of these ro­dents carry the virus and spread it mainly through urine and fae­ces, con­tam­i­nat­ing hu­man food.

The nasty thing about hanta, though, is that peo­ple can also be in­fected by in­hal­ing con­tam­i­nated air­borne dust, and in the fa­tal cases in Yosemite in 2012, the rus­tic ac­com­mo­da­tion proved an ideal en­vi­ron­ment for mice. Some of the park’s huts were con­demned as a con­se­quence.

An­other zoono­sis – but one that is un­likely to threaten most or­di­nary trav­ellers – is due to a vari­able par­a­sitic in­fec­tion called leish­ma­nia, aka kala-azar fever, which also causes pain­less trop­i­cal sores. It is most of­ten ac­quired – par­tic­u­larly in the Amer­i­cas – from the bites of tiny sand­flies, which will likely have first bit­ten an in­fected dog. Such dogs are of­ten mangy-look­ing mutts that hang about re­mote vil­lages and avoid­ing in­sect bites pro­tects you. In­deed, pre­ven­tion strate­gies for all these dis­eases over­lap with the pre­cau­tions ( see table) any sen­si­ble trav­eller will take.

Dr Jane Wil­son-howarth has moved back to Nepal, where she vol­un­teers with the ex­cel­lent char­ity PHASE https://phase­world­wide.org

Crowded house Lo­cals liv­ing along­side live­stock in cramped con­di­tions makes ru­ral China ripe for out­breaks

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