Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Women's Bodies Can Impede Less Desirable Sperm
A woman's body can act to lower less desirable sperm's chances of fertilizing an egg, researchers report.
They found that genetic compatibility between a woman's cervical mucus and a man's sperm affects the swimming motion, speed and viability of the sperm, CNN reported.
The study was published Aug. 19 in the journal Proceedings of the Royal Society B.
A previous study by the same researchers showed the same thing occurs in a woman's follicular fluid.
"The whole reproductive tract of the female seems to have evolved to filter out 'unwanted' spermatozoa," said the author of both studies, Jukka Kekalainen, an associate professor, Department of Environmental and Biological Sciences at the University of Eastern Finland, told CNN.
"We argue that cryptic female choice can potentially occur in multiple stages during the sperm migration from the vagina towards the unfertilized egg," she said.
The findings could help improve infertility treatment.
Between 30-40% of couples struggling with infertility don't know the exact cause, so if "both are diagnosed as fertile, it is possible 'gamete-level incompatibility concept' can help them to understand the reasons behind their reproductive problems," Kekalainen told CNN.
"Thus, we would encourage future infertility research to test the possibility that infertility is not always a pathological condition, but instead can also result in demonstrated evolutionary mechanism," she said.
California Has First Plague Case in Five Years
California's first case of plague in five years has been confirmed by health officials.
The patient, a resident of South Lake Tahoe, is receiving medical care while recovering at home, CBS News reported. Plague is easily treated with antibiotics if diagnosed early.
The patient is believed to have been bitten by an infected flea while walking a dog along the Truckee River corridor or in the Tahoe Keys area on Tahoe's south shore, according to health officials.
Fleas can acquire plague bacteria from infected chipmunks, squirrels and other wild rodents, and dogs and cats can also carry infected fleas, CBS News reported.
California's last confirmed plague cases were in 2015. Both patients were treated and recovered.
"It's important that individuals take precautions for themselves and their pets when outdoors, especially while walking, hiking and/or camping in areas where wild rodents are present," said El Dorado County Public Health Officer, Dr. Nancy Williams, CBS News reported. "Human cases of plague are extremely rare but can be very serious."