Here & Now

UW Entomologist Explains Zika Virus Risk In Wisconsin

NOW TO ENVIRONMENTAL NEWS. THERE HAVE BEEN NO CASES OF ZIKA VIRUS REPORTED IN WISCONSIN. AND THE SPECIES OF MOSQUITOES THAT CARRY THE VIRUS ARE NOT FOUND IN THIS STATE. HOWEVER, THAT SPECIES HAS BEEN REPORTED IN ILLINOIS, IOWA AND SOUTHERN MINNESOTA. CLOSE ENOUGH FOR THE STATE HEALTH DEPARTMENT WORKING WITH LOCAL HEALTH PARTNERS IN SOUTHERN WISCONSIN TO BEGIN SURVEILLANCE FOR IT. THAT SURVEILLANCE IS EXPECTED TO BEGIN IN LATE MAY OR EARLY JUNE. HERE TO TELL US ABOUT HOW THAT WILL WORK. AND TO REVIEW SOME OF THE HEALTH RISKS TO HUMANS THAT COME WITH THE ZIKA VIRUS IS UW-MADISON ENTOMOLOGIST DR. SUSAN PASKEWITZ. THANK YOU FOR BEING HERE.

SUSAN PASKEWITZ:

THANK YOU FOR HAVING ME.

FREDERICA FREYBERG:

SO AS WE JUST SAID IT HAS NOT BEEN FOUND IN WISCONSIN YET, BUT IN YOUR MIND IS IT JUST A MATTER OF TIME IF IT’S BEEN FOUND IN THESE SURROUNDING STATES?

SUSAN PASKEWITZ:

THE MOSQUITO THAT YOU’RE TALKING ABOUT IS THE ASIAN TIGER MOSQUITO. AEDES ALBOPICTUS IS ITS SCIENTIFIC NAME. IN AT LEAST 14 OR 15 TIMES THEY HAVE FOUND INFESTATIONS IN MINNESOTA. THEY’RE VERY GOOD AT WIPING THEM OUT. AND I THINK THEY HAVE A HARD TIME GETTING THROUGH THE WINTERS UP HERE. SO THEY GET REINTRODUCED INTO THE AREA PRETTY FREQUENTLY. THERE HAVE BEEN, AS YOU MENTIONED, ONE INSTANCE OF A TIRE PILE IN IOWA THAT WAS INFESTED. AND IN ILLINOIS THEY DO SEE THEM KIND OF SOUTH OF I-80. SO I THINK THERE’S AT LEAST A POSSIBILITY THAT THEY’RE INTRODUCED INTO OUR STATE. AND THAT WE MIGHT HAVE INFESTATIONS WE’RE NOT AWARE OF.

FREDERICA FREYBERG:

SURE. SO WHAT DOES THE SURVEILLANCE LOOK LIKE AND WHAT’S GOING TO BE HAPPENING WITH THAT?

SUSAN PASKEWITZ:

SO SURVEILLANCE FOR MOSQUITOES TAKES A COUPLE OF FORMS. ONE CAN LOOK FOR THE ADULT MOSQUITOES USING TRAPS USUALLY THAT PUT OUT SOME KIND OF CHEMICAL LURES WITH CARBON DIOXIDE. BUT IN THE CASE OF THESE MOSQUITOES THAT TRANSMIT ZIKA VIRUS, WE HAVE OTHER METHODS THAT ARE VERY EFFICIENT, ESPECIALLY IN PLACES WHERE YOU DON’T KNOW WHETHER THEY’RE ESTABLISHED YET OR NOT. SO IN OUR AREA WHAT WE’RE GOING TO BE USING IS SOMETHING CALLED OVA TRAPPING. WHAT AN OVA TRAP IS IS A CONTAINER FILLED WITH WATER THAT HAS A SUBSTRATE IN IT THAT THE MOSQUITOES WILL LAY THEIR EGGS ON. IT’S FAIRLY SPECIFIC FOR MOSQUITOES OF THIS TYPE SO THAT HELPS US A LOT. WHEN WE DO MORE GENERALIZED TRAPPING FOR ADULTS, WE CAN GET THOUSANDS AND THOUSANDS OF OTHER SPECIES, WHICH WOULD TAKE A LONG TIME TO SORT THROUGH. SO WITH THE OVA TRAPPING, THEY’RE SMALL, INEXPENSIVE CONTAINERS. WE CAN PUT OUT A LOT OF THEM IN A LOT OF DIFFERENT AREAS AND GET GOOD SOME SURVEILLANCE USING THAT TOOL.

FREDERICA FREYBERG:

THAT’S GOOD SURVEILLANCE TO TRAP THOSE EGGS, BUT DOES THAT THEN ALSO HELP KIND OF ERADICATE THEM?

SUSAN PASKEWITZ:

YOU KNOW, THERE ARE SOME METHODS THAT ARE BASED ON THAT TRAP DEVICE, WHERE YOU, IN ESSENCE, LURE THEM IN TO LAY THEIR EGGS THERE AND THEN YOU SPRAY A LITTLE BIT OF IN THIS CASE CANOLA OIL, SO SOMETHING VERY LOW IMPACT, AND THEY GET A BIT OF IT ON THEIR WINGS. IT MAKES THEM SO THEY CAN’T FLY AND YOU CAN REDUCE THE POPULATION AS WELL.

FREDERICA FREYBERG:

WHAT’S THE EXPLANATION FOR THE EXPLOSION IN MOSQUITO-BORNE ZIKA INFECTIONS IN CENTRAL AND SOUTH AMERICA?

SUSAN PASKEWITZ:

SO IT HAS AN INTERESTING HISTORY. THE VIRUS WAS FIRST FOUND IN A MONKEY IN UGANDA IN 1947. NOTHING REALLY HAPPENED FOR 60 YEARS. THEN THERE WAS AN OUTBREAK IN MICRONESIA AND THEN A FEW YEARS LATER IN FRENCH POLYNESIA IN 2013, 2014. AT THAT POINT PEOPLE THINK THAT THERE WAS IMPORTATION INTO BRAZIL AND PROBABLY ASSOCIATED WITH A CANOE RACE THAT HAPPENED.

FREDERICA FREYBERG:

WELL, WHAT’S REALLY SCARY ABOUT IT NOW, THOUGH, IS THAT IT IS SOMEHOW — I DON’T KNOW THE SCIENCE OF IT, BUT MORPHED INTO THIS VERY DANGEROUS INFECTION THAT CAUSES THIS MICROCEPHALY IN BABIES.

SUSAN PASKEWITZ:

RIGHT. RIGHT. I THINK PEOPLE ARE NOT SURE YET WHETHER THERE’S A RESULT OF A CHANGE IN THE VIRUS OR AN INTRODUCTION INTO A VERY LARGE POPULATION OF PEOPLE WHO HAVE NO IMMUNITY AT ALL. SO IT’S KIND OF A RARE OCCURRENCE. IN THE EARLIER OUTBREAKS IT WAS IN SMALL POPULATIONS. AND SO YOU REALLY DIDN’T SEE IT. IT DOESN’T HAPPEN VERY OFTEN. BUT OF COURSE IT’S DEVASTATING WHEN IT DOES HAPPEN.

FREDERICA FREYBERG:

CAN WOMEN BE TESTED TO SEE IF THEY HAVE THIS INFECTION IF THEY ARE OF CHILD-BEARING AGE?

SUSAN PASKEWITZ:

YES. IF PEOPLE HAVE SYMPTOMS OF ZIKA OR HAVE BEEN IN AREAS WHERE THEY HAVE BEEN EXPOSED TO ZIKA-BEARING VIRUSES, THERE ARE SOME TESTS THAT CAN BE DONE. USUALLY I THINK THE RECOMMENDATION IS THAT YOU WAIT FOR SYMPTOMS. YOU CAN USE A TEST THAT WILL LOOK FOR THE DNA OF THE VIRUS OR ANOTHER TEST THAT LOOKS TO SEE IF YOU’RE MAKING ANTIBODIES AGAINST THE VIRUS.

FREDERICA FREYBERG:

HOW SERIOUSLY IS THIS BEING TAKEN HERE IN WISCONSIN?

SUSAN PASKEWITZ:

YOU KNOW, IN WISCONSIN WE’RE LUCKY IN MANY WAYS BECAUSE WE DO THINK THAT THE LIKELY MOSQUITOES THAT WOULD BE DOING THE TRANSMISSION ARE NOT HERE. SO WE’RE NOT GOING TO BE A HOT SPOT FOR THIS VIRUS THIS SUMMER. MUCH MORE LIKELY THE GULF STATES, FLORIDA AND SO ON, WILL BE AT HIGH RISK. BUT THE STATE DEPARTMENT OF HEALTH IS TAKING THIS VERY SERIOUSLY, IS MAKING SURE THAT PREGNANT WOMEN WHO ARE TRAVELING INTO AREAS OR WOMEN WHO ARE THINKING OF TRAVELING TO THOSE AREAS WHERE THE VIRUS IS BEING TRANSMITTED ARE AWARE OF THE PRECAUTIONS THEY NEED TO TAKE. WHAT THEY SHOULD DO WHEN THEY COME BACK. AND THEY’RE BEING VERY PROACTIVE ABOUT SETTING UP SURVEILLANCE FOR THE MOSQUITO. SO IF WE DO HAVE ISSUES WE’LL KNOW ABOUT IT AND WE CAN MOVE IN AND DO SOMETHING QUICKLY.

FREDERICA FREYBERG:

DR. PASKEWITZ, THANKS VERY MUCH.

SUSAN PASKEWITZ:

THANK YOU.