Health
Scientists Built a Giant Human Scent Buffet to Learn How Mosquitoes Find Us
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Researchers created a giant sniffing arena for mosquitoes, all in hopes of understanding why they’re so drawn to us. Among other things, they found that human body odor was more alluring to the insects than the mere presence of carbon dioxide, a chemical that we exhale.
Plenty of research has tried to figure out how female bloodsucking mosquitoes find and choose the humans they feed on. But according to study author Conor McMeniman, these studies often find it hard to capture the complex nature of mosquito attraction. So, in partnership with researchers at the Macha Research Trust in Zambia, Africa, McMeniman and his team decided to build a more naturalistic setting for their experiments.
“In the laboratory, the majority of studies used to test mosquito smell preferences are performed on very small scales, in small boxes with volumes of around 0.5 cubic meters or less,” McMeniman, a researcher at the Johns Hopkins Bloomberg School of Public Health’s Malaria Research Institute, told Gizmodo. “For the study in Zambia, we used a structure called a semi-field flight cage—a screened structure with a volume of around 1,000 cubic meters, about 2,000 times the volume used for regular laboratory assays.”
Body heat alone didn’t bring the mosquitoes running over for a potential meal, the researchers found. The mosquitos did become attracted to the pads once carbon dioxide was added to the mix. But of the three factors, it was body odor that was the most alluring on its own to the bloodsuckers.
“In this study, we found that human scent is critical for the Anopheles gambiae to be drawn into the proximity of a potential host, whereby they then can detect warmth from the human skin,” McMeniman said. The team’s findings were published Friday in Current Biology.
As other research has shown, though, the mosquitos in this study had their clear favorites among the humans. And within people’s individual musks, the team identified chemical components that appeared to be incredibly attractive or repulsive.
“The most attractive individual had a scent signature with increased abundances of a number of light airborne carboxylic acids, as well as another chemical called acetoin that is likely produced by the skin microbiome,” McMeniman explained. “Interestingly, the individual that was least attractive in our screen had a scent signature that was radically different from the other volunteers—being enriched for a chemical called eucalyptol and depleted of a lot of other airborne chemicals found in other volunteers that were more attractive to mosquitoes, including the carboxylic acids we found.”
These findings suggest that high levels of eucalyptol in the body might be an great deterrent to mosquito bites. It’s likely that this person ate foods rich in the chemical, which is commonly found in herbs and spices, the authors say. But it’s also possible that he used external products that contain it, such as toothpaste and mouthwash.
“Understanding what chemicals in human scent drive differential attraction to certain humans is important, because if we can identify these chemicals, we can help to inform personal bite risk,” McMeniman said. This research could also help scientists develop better baits or traps.
More research is needed to confirm the team’s results. But this study is only the beginning of their work. Over the next few years, they plan to run larger experiments in Zambia that will involve over 100 humans. In the U.S., the team will be trying to better understand the entire library of chemicals that can be found in our scent. They’re hoping to eventually build a similar testing arena in the U.S. to study local disease-spreading mosquitoes.
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People struggling with mental health and substance abuse can access up to 12 free counselling sessions per year in a new Island Health program.
Leah Hollins, Island Health Board Chair, says “This represents a significant expansion and investment in community-based counselling services to improve access to these services on Vancouver Island.”
Virtual Island-wide services will be available through Cognito Health, and Trafalgar Addiction Treatment Centre. Services are also available in Port Hardy through North Island Crisis and Counselling Services and in Nanaimo through EHN Outpatient Services and Tillicum Lelum Aboriginal Society.
The publicly-funded, community-based counselling is intended for people with moderate challenges. The new partnership with Island health will meet the counselling needs of at least 1,500 people per year.
Access to the counselling services is via referral or self-referral through Island Health Mental Health and Substance Use locations.
Lyme disease in Quebec was back on the rise in 2021, following a brief slowdown in 2020.
According to data released earlier this week by Quebec’s public health institute (INSPQ), 709 cases of Lyme disease were reported to provincial health authorities as of April 6, 2022. Of those infections, 650 were likely acquired in Quebec, while the rest occurred elsewhere.
The rate of the disease in 2021 was 1.7 times higher than in 2019, the year with the second-highest recorded rate.
Of the 650 cases of Lyme disease acquired in Quebec, Estrie was again the most affected region. With 452 cases, it accounts for nearly 70 per cent of all infections in Quebec.
Authorities reported 124 cases in Montérégie.
The other regions, including Montreal, reported fewer than 20 cases.
The age group most affected by Lyme disease in Quebec in 2021 was 60-69, followed by 50-59, 40-49 and 70-79.
Lyme is transmitted through the bite of a tick carrying the disease.
The tell-tale symptom in humans is a reddening of the skin. Many with the disease experience fatigue, fever, aches and pains — and if the disease isn’t detected and treated quickly, the bacteria can disperse into the bloodstream, leading to much more uncomfortable symptoms.
According to the Quebec government, milder winters could partly explain the disease’s progression. The warmer climate allows ticks to survive and reproduce more easily.
Lyme disease has been a notifiable disease in Quebec since 2003, meaning doctors and laboratory technicians who detect a case must inform public health authorities.
This report by The Canadian Press was first published in French on June 9, 2023.
Health
Aggressive, ‘drooling profusely’ moose has disease never seen in its species in Alaska – Yahoo Canada Sports
A moose that was acting aggressively toward people has been diagnosed with rabies, a first for Alaska, according to wildlife officials.
The moose, which was “stumbling, drooling profusely, and had bare patches of skin,” was found acting oddly in Teller on June 2, the Alaska Department of Fish and Game said in a June 7 news release.
“That moose was being aggressive towards people and charging and getting a little bit too close to comfort for them,” Alaska Wildlife Biologist Sara Germain told KTUU-TV.
Before the moose’s carcass was burned, wildlife officials said they collected samples for testing, which showed “rabies virus in the brain.”
Further, the Centers for Disease Control and Prevention confirmed the virus in the moose was infected with was “an Arctic Fox rabies variant,” officials said. The variant stems from a winter rabies outbreak in Nome/Seward Peninsula and North Slope arctic foxes.
Wildlife officials said this suggests the moose contracted the disease from a fox.
“Due to the largely solitary nature of moose, it is very unlikely that any rabies outbreak will occur in the moose population, but isolated cases such as this one occur rarely,” officials said.
While rabies in moose is rare, some of the massive animals have been “diagnosed with rabies in South Dakota, Minnesota, Canada and Russia,” officials said.
The department said as a result of this rabies case that it plans to test “all brain samples from wild mammals found dead or euthanized from regions” known to have fox rabies, to better track the disease.
The public can help by calling the department if they find a dead animal or see any that with signs of rabies, which includes “excessive salivation, abnormal / aggressive behavior, bite marks,” officials said.
Though photos and videos can be helpful, it’s important to avoid contact “with a rabid animal or carcass,” officials said.
Rabies vaccines for dogs and cats is the best protection against the disease in people, according to officials.
“Likewise, preventing pets from interacting with foxes or other wildlife, and not leaving garbage or other attractants accessible to foxes and other wildlife, remain important,” the department said.
If someone is bitten by an animal that may have been exposed to rabies, “immediately wash the wound with soap and water and seek medical attention,” officials said.
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