Latest news with #microbiologist
Gizmodo
5 days ago
- Health
- Gizmodo
This Cat Poop Parasite Can Decapitate Sperm—and It Might Be Fueling Infertility
Male fertility rates have been plummeting over the past half-century. An analysis from 1992 noted a steady decrease in sperm counts and quality since the 1940s. A more recent study found that male infertility rates increased nearly 80% from 1990 to 2019. The reasons driving this trend remain a mystery, but frequently cited culprits include obesity, poor diet, and environmental toxins. Infectious diseases such as gonorrhea or chlamydia are often overlooked factors that affect fertility in men. Accumulating evidence suggests that a common single-celled parasite called Toxoplasma gondii may also be a contributor: An April 2025 study showed for the first time that 'human sperm lose their heads upon direct contact' with the parasite. I am a microbiologist, and my lab studies Toxoplasma. This new study bolsters emerging findings that underscore the importance of preventing this parasitic infection. The many ways you can get toxoplasmosis Infected cats defecate Toxoplasma eggs into the litter box, garden or other places in the environment where they can be picked up by humans or other animals. Water, shellfish and unwashed fruits and vegetables can also harbor infectious parasite eggs. In addition to eggs, tissue cysts present in the meat of warm-blooded animals can spread toxoplasmosis as well if they are not destroyed by cooking to proper temperature. While most hosts of the parasite can control the initial infection with few if any symptoms, Toxoplasma remains in the body for life as dormant cysts in brain, heart and muscle tissue. These cysts can reactivate and cause additional episodes of severe illness that damage critical organ systems. Between 30% and 50% of the world's population is permanently infected with Toxoplasma due to the many ways the parasite can spread. Toxoplasma can target male reproductive organs Upon infection, Toxoplasma spreads to virtually every organ and skeletal muscle. Evidence that Toxoplasma can also target human male reproductive organs first surfaced during the height of the AIDS pandemic in the 1980s, when some patients presented with the parasitic infection in their testes. While immunocompromised patients are most at risk for testicular toxoplasmosis, it can also occur in otherwise healthy individuals. Imaging studies of infected mice confirm that Toxoplasma parasites quickly travel to the testes in addition to the brain and eyes within days of infection. In 2017, my colleagues and I found that Toxoplasma can also form cysts in mouse prostates. Researchers have also observed these parasites in the ejaculate of many animals, including human semen, raising the possibility of sexual transmission. Knowing that Toxoplasma can reside in male reproductive organs has prompted analyses of fertility in infected men. A small 2021 study in Prague of 163 men infected with Toxoplasma found that over 86% had semen anomalies. A 2002 study in China found that infertile couples are more likely to have a Toxoplasma infection than fertile couples, 34.83% versus 12.11%. A 2005 study in China also found that sterile men are more likely to test positive for Toxoplasma than fertile men. Not all studies, however, produce a link between toxoplasmosis and sperm quality. Toxoplasma can directly damage human sperm Toxoplasmosis in animals mirrors infection in humans, which allows researchers to address questions that are not easy to examine in people. Testicular function and sperm production are sharply diminished in Toxoplasma-infected mice, rats and rams. Infected mice have significantly lower sperm counts and a higher proportion of abnormally shaped sperm. In that April 2025 study, researchers from Germany, Uruguay, and Chile observed that Toxoplasma can reach the testes and epididymis, the tube where sperm mature and are stored, two days after infection in mice. This finding prompted the team to test what happens when the parasite comes into direct contact with human sperm in a test tube. After only five minutes of exposure to the parasite, 22.4% of sperm cells were beheaded. The number of decapitated sperm increased the longer they interacted with the parasites. Sperm cells that maintained their head were often twisted and misshapen. Some sperm cells had holes in their head, suggesting the parasites were trying to invade them as it would any other type of cell in the organs it infiltrates. In addition to direct contact, Toxoplasma may also damage sperm because the infection promotes chronic inflammation. Inflammatory conditions in the male reproductive tract are harmful to sperm production and function. The researchers speculate that the harmful effects Toxoplasma may have on sperm could be contributing to large global declines in male fertility over the past decades. Preventing toxoplasmosis The evidence that Toxoplasma can infiltrate male reproductive organs in animals is compelling, but whether this produces health issues in people remains unclear. Testicular toxoplasmosis shows that parasites can invade human testes, but symptomatic disease is very rare. Studies to date that show defects in the sperm of infected men are too small to draw firm conclusions at this time. Additionally, some reports suggest that rates of toxoplasmosis in high-income countries have not been increasing over the past few decades while male infertility was rising, so it's likely to only be one part of the puzzle. Regardless of this parasite's potential effect on fertility, it is wise to avoid Toxoplasma. An infection can cause miscarriage or birth defects if someone acquires it for the first time during pregnancy, and it can be life-threatening for immunocompromised people. Toxoplasma is also the leading cause of death from foodborne illness in the United States. Taking proper care of your cat, promptly cleaning the litter box and thoroughly washing your hands after can help reduce your exposure to Toxoplasma. You can also protect yourself from this parasite by washing fruits and vegetables, cooking meat to proper temperatures before consuming and avoiding raw shellfish, raw water and raw milk. Bill Sullivan, Professor of Microbiology and Immunology, Indiana University. This article is republished from The Conversation under a Creative Commons license. Read the original article.
CBC
28-05-2025
- Health
- CBC
'How's my technique?' Your handwashing habits still need work
A Canadian microbiologist says pandemic handwashing habits likely didn't stick. An Ottawa hospital is turning to technology to make sure they get better.
Yahoo
25-05-2025
- Health
- Yahoo
YAHOO POLL: When in the day is best to take a shower?
In hot and humid Singapore, a minimum of one shower a day is probably a given — is it? How many times do you shower a day and when do you shower? Experts have now weighed in on whether it is better to shower in the morning or at night. Several have said that morning showers are better for our bodies and hygiene. Other polls: YAHOO POLL: Do you agree with SDP's push for election system reform? YAHOO POLL: Do you support harsher punishments for animal abusers? YAHOO POLL: COVID-19 cases on the rise – are you staying vigilant? One reason: Our bodies "collect pollutants" throughout even as we sleep as "most people don't wash their bedsheets every day, so if you're showering before bed, you'll still likely be jumping onto sheets that contain various bacteria from previous nights". One expert shared, "As a microbiologist, I am a day-shower advocate. A morning shower suggests your body will be cleaner of night-acquired skin microbes when putting on fresh clothes." What do you think? When is a good time for a shower in Singapore? Tell us what you think. Related So, How Often Do You Really Need to Shower? How Often Should You Shower? Here's What a Dermatologist Has to Say Gen Z-ers spend the longest time in the shower, new poll reveals. Here's what experts say about our washing habits.
CNA
20-05-2025
- Health
- CNA
Commentary: Is it better to shower in the morning or at night? Here's what a microbiologist says
LEICESTER, England: It's a question that's long been the cause of debate: Is it better to shower in the morning or at night? Morning shower enthusiasts will say this is the obvious winner, as it helps you wake up and start the day fresh. Night shower loyalists, on the other hand, will argue it's better to 'wash the day away' and relax before bed. But what does the research actually say? As a microbiologist, I can tell you there actually is a clear answer to this question. BENEFITS OF SHOWERING First off, it's important to stress that showering is an integral part of any good hygiene routine – regardless of when you prefer to have one. Showering helps us remove dirt and oil from our skin, which can help prevent skin rashes and infections. Showering also removes sweat, which can quell body odour. Although many of us think that body odour is caused by sweat, it's actually produced by bacteria that live on the surface of our skin. Fresh sweat is, in fact, odourless. But skin-dwelling bacteria – specifically staphylococci – use sweat as a direct nutrient source. When they break down the sweat, it releases a sulphur-containing compound called thioalcohols which is behind that pungent BO stench many of us are familiar with. DAY OR NIGHT? During the day, your body and hair inevitably collect pollutants and allergens (such as dust and pollen) alongside their usual accumulation of sweat and sebaceous oil. While some of these particles will be retained by your clothes, others will inevitably be transferred to your sheets and pillow cases. The sweat and oil from your skin will also support the growth of the bacteria that comprise your skin microbiome. These bacteria may then also be transferred from your body onto your sheets. Showering at night may remove some of the allergens, sweat and oil picked up during the day so less ends up on your bed sheets. However, even if you've freshly showered before bed, you will still sweat during the night – whatever the temperature is. Your skin microbes will then eat the nutrients in that sweat. This means that by the morning, you'll have both deposited microbes onto your bed sheets, and you'll probably also wake up with some BO. A night shower can help rinse away the day's dirt and grime, but you might not smell as fresh the next morning. What particularly negates the cleaning benefits of a night shower is if your bedding is not regularly laundered. The odour-causing microbes present in your bed sheets may be transferred while you sleep onto your clean body. Showering at night also does not stop your skin cells being shed. This means they can potentially become the food source of house dust mites, whose waste can be allergenic. If you don't regularly wash your sheets, this could lead to a build-up of dead skin cell deposits which will feed more dust mites. The droppings from these dust mites can trigger allergies and exacerbate asthma. Morning showers, on the other hand, can help remove dead skin cells as well as any sweat or bacteria you've picked up from your bed sheets during the night. This is especially important to do if your sheets weren't freshly washed when you went to bed. A morning shower suggests your body will be cleaner of night-acquired skin microbes when putting on fresh clothes. You'll also start the day with less sweat for odour-producing bacteria to feed on – which will probably help you smell fresher for longer during the day compared to someone who showered at night. As a microbiologist, I am a day shower advocate. IMPORTANCE OF WASHING YOUR SHEETS Of course, everyone has their own shower preference. Whatever time you choose, remember that the effectiveness of your shower is influenced by many aspects of your personal hygiene regime – such as how frequently you wash your bed sheets. So regardless of whether you prefer a morning or evening shower, it's important to clean your bed linen regularly. You should launder your sheets and pillowcases at least weekly to remove all the sweat, bacteria, dead skin cells and sebaceous oils that have built up on your sheets. Washing will also remove any fungal spores that might be growing on the bed linen – alongside the nutrient sources these odour-producing microbes use to grow.
Washington Post
14-05-2025
- Health
- Washington Post
Are beards really dirtier than toilet seats?
Is it true that beards are dirtier than toilets? No need to reach for the razor just yet. While your facial hair is crawling with microorganisms, it's very unlikely that your mustache or beard is germier than your commode. The notion that beards are potential carriers of disease dates back about six decades. In a 1967 study, microbiologist Manuel S. Barbeito and his colleagues sprayed participants' beards with bacteria and found that the bacteria remained after washing with soap and water.
