By PEOPLE.COM/Erin Hill, Monique Jessen
Oct 25, 2018 @ 3:30 pm

Meghan Markle is taking every precaution against the Zika virus during her trip to Tonga.

As the royal mom-to-be stepped out on Wednesday evening to attend a welcome reception and dinner in with King Tupou VI and Queen Nanasipauʻu, it was impossible not to notice her super shiny arms.

After wearing several long-sleeved dresses during her visit in Fiji, Meghan opted for a capped-sleeve dress for her latest engagement, but she still protected her arms against mosquitos with insect repellent.

“The advice would be to wear a repellent which contains an active ingredient and wear that repellent all day and all evening,” Professor James G. Logan, Head of the Department of Disease Control at the London School of Hygiene and Tropical Medicine, tells People.

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“You have to put the repellent on like a hand cream. You have to really rub it in. If you squirt it on like a perfume, that won’t do anything because the mosquito will find a bit that’s not covered. A spray or a lotion is fine but really rub it in and reapply it often. There are four active ingredients, one of the main ones is DEET and it’s safe to use that during pregnancy.”

The World Health Organization classified Tonga in March as a “Category 1” risk, an “area with new introduction or re-introduction with ongoing transmission” of the Zika virus, which can cause serious birth defects, including microcephaly.

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Harry and Meghan sought medical advice about the Zika virus ahead of their tour and decided not to make any changes to their schedule, however, Meghan avoided a trip into the forest during their visit to Fiji, while Harry went solo.

“Wearing long sleeves and baggy clothes will help,” Logan adds. “Mosquitos can even bite through jeans so if the clothing is loose it’s much harder for the mosquito to bite. Wearing light-colored clothing can help as these mosquitos are often attracted to dark clothing. It also helps you spot them, if you see a dark mosquito on a light piece of clothing.”

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Since touching down Down Under, Meghan and Harry have kept a full calendar at a busy pace, opening the Anzac Memorial for fallen veterans, opening the Anzac Memorial for fallen veterans, opening the Invictus Games, stepping out on Bondi Beach and even receiving their “first baby gift.”

After her pregnancy announcement, a royal source told People Meghan had had her 12-week ultrasound and was “feeling well.”