The Zika Virus Ex­plo­sion, A Per­spec­tive

Asian Journal - - Front Page - Ray Hud­son

Just over two months ago, we spoke with Dr. Suni Bo­ras­ton, Di­rec­tor of the Van­cou­ver Coastal Health Travel Clinic about pre­cau­tions and vac­ci­na­tions trav­ellers should take while va­ca­tion­ing in the trop­ics. One of the dis­eases she men­tioned was the zika virus, a mild and short du­ra­tion virus, re­lated to dengue and yel­low fever, but much less vi­ra­lent. On Fe­bru­ary 1, 2016, within two months of the ear­lier re­port, the zika virus was de­clared a pub­lic health emer­gency by the World Health Or­ga­ni­za­tion (WHO) fol­low­ing sto­ries of ba­bies, in Brazil, be­ing born with un­der­de­vel­oped heads, tech­ni­cal name: mi­cro­cephaly.

Here’s some back­ground:

The zika virus, was first iden­ti­fied in the forests of Uganda in 1947, the first hu­man in­fec­tions re­ported in 1952. Since that time there have been out­breaks re­ported across trop­i­cal Africa, South­east Asia, the Pa­cific Is­lands, Cen­tral and South Amer­ica, with some in­fec­tions be­ing re­ported in the South­ern US, and now in China. So far, there have been no re­ports of in­fec­tions in In­dia, how­ever the coun­try is on alert and pre­par­ing for what ap­pears to be the in­evitable. The dis­ease is spread by the bite of the Aedes mos­quito, which be­comes the vec­tor (source of in­fec­tion) by tak­ing the blood of an­other in­di­vid­ual in­fected with the zika virus. This is the same mos­quito that spreads the much nas­tier: dengue fever, also known as “break-bone fever,” yel­low fever, and chikun­gunya (pro­nounced Chik-un-goon-ya) a Makonde word mean­ing “that which bends up.” One im­por­tant thing about the Aedes mos­quito, is that it is ac­tive in the day. Ac­cord­ing to the WHO, the peak bit­ing pe­ri­ods are early in the morn­ing and in the evening be­fore dusk, un­like the anophe­les mos­quito, which is the vec­tor for malaria and is only ac­tive at night. Ac­cord­ing to the Cen­tre for Dis­ease Con­trol (CDC) the zika virus pro­duces a much milder fever, headache, rash, joint pains, ab­dom­i­nal pain di­ar­rhea and vom­it­ing. Usu­ally the symp­toms are mild and dis­ap­pear on their own. Some peo­ple may not re­al­ize they’ve been in­fected at all.

We re­turned to the Van­cou­ver Coastal Health’s Travel Clinic and spoke with Dr. Bo­ras­ton about this dra­matic shift in at­ten­tion be­ing brought on this seem­ingly weaker cousin and asked if the zika virus is as big a prob­lem as it’s be­ing pre­sented, or is it a case of over-re­port­ing.

“We don’t know that yet,” Dr. Bo­ras­ton replied. “The full an­swer is that we’ve been watch­ing the zika virus for a num­ber of years. There was a big out­break in French Poly­ne­sia in 2013, and it slowly spread across Cen­tral and South Amer­ica. Columbia had a huge out­break about 18 months ago, but it was Brazil’s out­break that alerted us to an in­crease in mi­cro­cephaly, ba­bies born with a re­duced head size. It was Brazil that tweaked to that, but at the same time Brazil had also done some things that in­creased their re­port­ing of mi­cro­cephaly. They changed the def­i­ni­tion of mi­cro­cephaly and they made it a re­portable dis­ease.” Those are what are called con­founders. Dr. Bo­ras­ton said she had no doubt that there is a link be­tween the zika virus and mi­cro­cephaly, but added that they don’t know how much yet. “There is a bi­o­logic ba­sis for this,” Dr. Bo­ras­ton said. “If a preg­nant woman is in­fected with rubella, tox­o­plas­mo­sis, or cy­tomegalovirus, the baby can have mi­cro­cephaly. But the num­ber of cases that Brazil was re­port­ing was huge, some­thing like four thou­sand new cases from Oc­to­ber 2015 to Jan­uary 2016. It’s a sus­pi­ciously high num­ber. So they looked at French Poly­ne­sia again, and they did re­port an in­crease in mi­cro­cephaly over the time of the zika out­break; 78 cases more than ex­pected.” She said that the process will be re­peated in Columbia to see if they had an in­crease, and then they’ll go back and look at what was ac­tu­ally hap­pen­ing in Brazil. “So I don’t think it’s as scary as the me­dia is mak­ing it,” Dr. Bo­ras­ton said, “but there’s no doubt that if you’re a preg­nant woman go­ing down to one of those ar­eas, you should think twice about it. We’re telling women who are bound and de­ter­mined to go, to use in­sect pre­cau­tions. Preg­nant women can safely use re­pel­lants, long sleeves, long pants, no per­fumes.” With re­spect to re­pel­lents, Dr. Borston said the most ef­fec­tive prod­ucts con­tain an un­pro­nounce­able chem­i­cal com­pound known as DEET. “DEET is safe,” she replied to a ques­tion about its safety. “The only peo­ple who got into trou­ble with DEET were in­fants where it was overused. They had some rev­ersible neu­ro­log­i­cal is­sues. But it’s safe for chil­dren and adults who use it prop­erly.” There has been some con­fu­sion about how long women may be at risk fol­low­ing ex­po­sure. The coun­tries, where zika is en­demic, are say­ing women should wait two years be­fore they get preg­nant. How­ever, this ad­vice is di­rected at women liv­ing in en­demic ar­eas. The ad­di­tional time pe­riod pro­vides an op­por­tu­nity to get the out­break un­der con­trol. “For women who want to travel to zika ar­eas,” Dr. Bo­ras­ton said, “we sug­ge­set they wait two months af­ter be­ing in a zika area be­fore try­ing to get preg­nant. I think that two months is overkill for women. We know this is a very quick dis­ease. It’s got a short in­cu­ba­tion pe­riod, and once it’s gone, it’s done and gone.” Men? Who knows? There have been a num­ber of cases where the zika virus has been found in se­men and in some cases trans­mit­ted it to sex­ual part­ners, in one case, they found the virus in se­men 62 days af­ter the orig­i­nal in­fec­tion. As a re­sult, men are be­ing told to wait two months be­fore hav­ing un­pro­tected sex, and if the trav­eller has a preg­nant part­ner at home, he shouldn’t have un­pro­tected sex for the du­ra­tion of the preg­nancy.” An­other wrin­kle in the zika story is that it ap­pears to be linked to Guil­lain-Barre syn­drome (GBS). “The French Poly­ne­sian out­break showed that there does seem to be a greater in­ci­dence of GBS,” said Bo­ras­ton, “but there was only a slightly higher in­crease to what they were ex­pect­ing.” GBS is a neu­ro­log­i­cal ill­ness that can cause ma­jor fa­tigue and mus­cle wast­ing. You can end up in an ICU on a res­pi­ra­tor for the du­ra­tion of the ill­ness, but it is rev­ersible. You can also get GBS from in­fluenza and campy­lobac­ter, which is like a bad food poi­son­ing. Asked about the de­vel­op­ment of a vac­cine, Dr Bo­ras­ton said that re­searchers are work­ing on it. She said they have just de­vel­oped a vac­cine against dengue fever, for use in en­demic coun­tries like Mex­ico, Brazil and the Philip­pines, and ex­pect they might be able to use the same tech­nol­ogy in de­vel­op­ing the zika vac­cine. They are hop­ing to have it out in eigh­teen months. Zika is cer­tainly a dis­ease to be un­der­stood and re­spected, how­ever Malaria con­tin­ues to be the most ef­fi­cient killer around the world. In 2015 (ac­cord­ing to the WHO), there were 214 mil­lion cases of malaria re­sult­ing in an es­ti­mated 430,000 deaths. With cli­mate warm­ing, is there any con­cern with zika mov­ing north? The south­ern United States al­ready has the right mos­quito for zika, but Dr. Bo­ras­ton doesn’t think it will move north. “We don’t have the vec­tor (mos­quito) here de­spite the leg­endary vo­ra­cious­ness of mos­qui­toes in Canada,” said Dr. Bo­ras­ton. “Could they be­come car­ri­ers for this virus? I just read that they are do­ing the stud­ies to de­ter­mine if that very thing is a pos­si­bil­ity, but I doubt that it would find the north­ern mos­qui­toes a very ef­fi­cient vec­tor. The West Nile virus never re­ally got a hold here. It gets too cold and the virus couldn’t sur­vive that.”

For more in­for­ma­tion on this and other travel in­for­ma­tion, please go on­line at http://trav­el­clinic.vch.ca

Photo: Ray Hud­son

Dr. Suni Bo­ras­ton in­di­cat­ing the trop­ics as the Zika hot spot.

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.