Canadian athletes and medical staff were greeted by a few things they didn't expect when they arrived at the Rio Olympics: a conspicuous absence of mosquitoes and improved water quality off Copacabana Beach.
Canada's chief medical officer, Bob McCormack, said the view from on the ground in Rio has eased some of the team's worst fears ahead of the Games. Pre-Olympic worries over the mosquito-borne Zika virus and sky-high bacterial counts in Rio's infamously sewage-infested water where swimming events will be contested are still a concern, but there are encouraging signs on both fronts.
Recent tests have shown the country's efforts to improve the water quality in certain areas around Rio have had positive results over the past year, he said. Meanwhile, Team Canada's head doctor said after one week in Rio, he's still on the lookout for his first mosquito.
"To be honest, we've seen very few mosquitoes in the village," McCormack said.
Some of that is due to the city's effort to quell mosquito outbreaks through a widespread spraying campaign, particularly in areas with standing water. But the biggest factor affecting the mosquitoes is most likely the cooler weather in the Brazilian winter. Daytime temperatures have been in the low- to mid-20s, dropping into the mid-teens at night. Recent data have shown infection rates for mosquito-borne Zika and dengue fever falling to about 2 per cent.
"If you look at the data that has come out over the last couple of months, the incidences of Zika and dengue fever and other mosquito-borne viruses has just fallen off a cliff. It's almost disappeared completely," McCormack said.
Still, with other countries' athletes on full-on mosquito alert – the South Korean team arrived in Rio wearing long-sleeve uniforms pretreated with bug repellent – the Canadians are remaining cautious.
"We're leaving it up to the athletes, but our recommendations are that when you're out at dusk and dawn, the times that mosquitoes are prominent, [wear] appropriate barrier clothing and mosquito repellent," McCormack said.
That includes the opening ceremony on Friday, where swimmer Brittany MacLean will be taking part. She said athletes are focusing on what they can control, including using mosquito repellant, but not worrying too much.
"We've been doing everything we can to protect ourselves," she said. "Everyone's taking the precautions necessary and we can't really control the amount of bugs," she said. "[But] it's not like we've seen a huge swarm. I've seen a few, but nothing too bad."
The Zika virus has been a concern given its possible link to deformities in babies and to neurological problems in adults. But swimmer Audry Lacroix said the lack of mosquitoes around has eased athletes' concerns.
"I haven't seen a mosquito to date," she said. "It's not really something that's worrying athletes."
Rio's water quality is the other major concern, due to the city's long-standing practice of letting raw sewage to flow to the sea. Asked if he would compete in the water off Copacabana Beach, McCormack said he has ventured there several times to swim. The area is where the open-water swimming, including in the triathlon, will be contested. In recent months, swimmers have been told to do their best to keep their mouths closed when competing.
McCormack said he has not gotten ill from his swimming excursions there, but said he didn't take in much water. "I don't swallow the water when I swim at home either, but I've been on the beach and enjoyed it the last time I was here."
Independent tests done by the Associated Press last year suggested that ingesting as little as one teaspoon of water would have a 99-per-cent certainty of making athletes sick.
More recent reports have said three-teaspoons of water would cause illness.
"We paid a lot of attention," McCormack said of those results, particularly when athletes participated in a test competition there last August. Several countries shared health information after that event.
"In the test event for the open-water swim – that's 10 kilometres of putting your face in the water – none of those 50 athletes got sick," he said.
That said, Canada's open-water swimmers are taking prophylactic medication, such as antibiotics, to hopefully ward off problems. McCormack said Brazilian officials have been working with the World Health Organization and have been sharing water-quality reports amid cleanup efforts. Those include water-diverting booms and infrastructure improvements, which he said appear to be having an effect.
Though it doesn't mean Rio's reputation for dirty water will no longer apply, it means the picture looks a bit better than it did. "At the moment … it's better than it has been in the past," he said.
"Looking at the water-quality reports, which we've continued to monitor closely, the water quality for the open-water swim and triathlon is excellent. It's as good as the water in most of Canada. It meets all international standards," McCormack said.
"The testing that's been done has shown that the things we do to measure quality – the coliform counts, the E. coli counts – meet all international standards. I'm from Vancouver, if I went swimming in False Creek or in English Bay, I'd have the same potential risk of getting sick of swimming. The risks are low."
"To be honest, I can't tell you the coliform counts in False Creek but if you're from the West Coast you know that occasionally the beaches around Stanley Park are closed because they fail to meet international standards … There are many jurisdictions in Canada that intermittently have problems with water quality."
He added that the Canadian officials trust the data they are getting from Brazil and the WHO on the water testing.
He said athletes appear to have put those concerns behind them for now.
"The most pressing question from the athletes is what's the WiFi code [in the athlete's village]" McCormack said.
McCormack's comments on water quality come in spite numerous reports in recent weeks questioning whether Rio's handling of the pollution situation has been enough to make competition acceptable.
With a file from Ingrid Peritz