weird stuff

Mosquitoes want more human blood

Mosquitoes are increasingly turning to humans for their next meal as biodiversity loss strips them of traditional animal hosts, scientists have warned.

New research from Brazil's Atlantic Forest -- one of the most biodiverse regions on Earth -- shows that mosquitoes are now far more likely to feed on people than wildlife, even inside protected forest reserves.

The shift raises serious concerns about the spread of dangerous mosquito-borne diseases.

Researchers believe habitat destruction is driving the change. As deforestation and human activity shrink forest ecosystems, many animals disappear -- leaving mosquitoes with fewer blood sources and pushing them towards people instead.

Sergio Machado, from the Federal University of Rio de Janeiro, said the findings are "crucial, because in an environment like the Atlantic Forest with a great diversity of potential vertebrate hosts, a preference for humans significantly enhances the risk of pathogen transmission".

The findings are troubling because mosquitoes in the Atlantic Forest can carry viruses responsible for yellow fever, dengue, Zika, chikungunya, Mayaro and Sabia -- all of which pose serious health risks.

"With fewer natural options available, mosquitoes are forced to seek new, alternative blood sources.

"They end up feeding more on humans out of convenience, as we are the most prevalent host in these areas," Machado said.

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Long COVID linked to Alzheimer's

Long COVID may carry a worrying legacy for the brain, with scientists warning that persistent neurological symptoms after infection could raise the risk of Alzheimer's disease later in life.

Researchers in the US analysing blood samples from more than 225 long Covid patients found significantly increased levels of tau -- a protein closely linked to Alzheimer's and other forms of dementia.

Abnormal tau can clump together inside nerve cells, disrupting communication in the brain and driving the memory loss and cognitive decline that define the disease.

The findings suggest that symptoms such as brain fog, headaches, vertigo, and changes in smell or taste may not simply be lingering annoyances, but possible early warning signs of long-term neurological damage.

Dr Benjamin Luft, an infectious disease expert and lead author of the study, said: "The long-term impact of COVID-19 may be consequential years after infection and could give rise to chronic illnesses, including neurocognitive problems similar to those seen in Alzheimer's disease."

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Male sex drive strongest in their 40s -- study

Male sexual desire may not fade as early as many assume.

A large international study suggests that men's libido typically reaches its highest point in middle age -- not in their teenage years, but in their early 40s.

Researchers analysing data from more than 67,000 adults age between 20 and 84, found that men's self-reported sexual desire steadily increased through early adulthood, peaked around the age of 40, and only then began a slow decline. It was not until men reached their 60s that libido levels fell back to those typically reported by men in their 20s.

The findings, published in the journal Scientific Reports, challenge the long-held belief that sexual desire is driven mainly by biology and declines in a straight line with age.

Testosterone levels, the primary male sex hormone, usually begin to fall from the early 30s. Yet sexual appetite showed no sign of dipping for another decade.