Latest news with #ToxoplasmaGondii
Gizmodo
4 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.
The Sun
4 days ago
- Health
- The Sun
New threat to plummeting male fertility rates identified as common but ‘silent' parasite that ‘DECAPITATES sperm'
FERTILITY rates appear to have been declining in both men and women globally - and now scientists have found a common single-celled parasite may be a contributor. Male fertility rates in particular have been plummeting over the past half-century, with an analysis from 1992 showing a steady decrease in sperm counts and quality since the 1940s. 3 3 And a more recent study found male infertility rates increased nearly 80 per cent from 1990 to 2019. Declining fertility rates have been attributed to a combination of factors, including rising costs associated with raising children. But now accumulating evidence suggests parasitic infections could also be a threat. A study published in April this year showed for the first time "human sperm lose their heads upon direct contact" with a parasite called Toxoplasma gondii. Toxoplasma gondii causes toxoplasmosis - an often harmless infection but can cause serious problems in individuals with weakened immune systems, pregnant women, and newborns. The parasite is found in the faeces of infected cats and in undercooked meat. Writing for The Conversation, Bill Sullivan, Professor of Microbiology and Immunology, Indiana University, said how the "new study bolsters emerging findings that underscore the importance of preventing this parasitic infection". Foodbourne transmission and animal to human transmission are the top ways people can get toxoplasmosis. Eating raw or undercooked meat, particularly lamb, pork, and venison, is a primary source of infection. And eating unwashed fruits and vegetables that have been contaminated with cat faeces or soil can also lead to infection. Major health advice for couples as HSE offers new resources for anyone struggling with fertility Ingesting the parasite through contact with cat faeces (poop) or soil contaminated with cat faeces is a common way to get toxoplasmosis. Cleaning cat litter boxes without proper hygiene can also expose people to the parasite. While toxoplasmosis is generally harmless for most people with healthy immune systems, often causing no symptoms or mild, flu-like symptoms that resolve on their own, Sullivan said toxoplasma remains in the body for life as dormant cysts in brain, heart and muscle tissue. And these cysts can reactive and cause additional episode of severe illness that damage critical organ system. He explains: "Between 30 per cent and 50 per cent of the world's population is permanently infected with toxoplasma due to the many ways the parasite can spread. "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. 3 "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." Evidence in past studies suggesting toxoplasma can reside in male reproductive organs has prompted analysis of fertility in infected men. In the April 2025 study, researchyers from Germany, Uraguay 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. Looking at what happens when the parasite comes into direct contact with human sperm in a test tube, they observed that after only five minutes, 22.4 per cent of sperm cells were beheaded. The number of decapitated sperm also increased the longer they interacted with the parasites. Sperm cells that maintained their head were often twisted and misshapen, and sperm cells had hole sin their head, suggesting the parasites were trying to invade them as it would any other type of cell. Sullivan added: "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." Could you have toxoplasmosis? Toxoplasmosis is a common infection that you can catch from the poo of infected cats, or infected meat. It's usually harmless but can cause serious problems in some people. Most people who become infected with the toxoplasma gondii parasite don't show any signs of infection. The parasite can reside in the body for life without causing issues. However, if you do have symptoms, they can be mild and flu-like, such as fever, swollen lymph nodes, and muscle aches. According to the NHS, some people may have more serious symptoms including: confusion blurred vision slurred speech unsteady walking Your GP may do blood tests to see if you've been infected with toxoplasmosis. They can also prescribe medicines to treat the infection if necessary. Most people who get toxoplasmosis get better without treatment. However, you'll usually be given medicines, including antibiotics, if you: are pregnant have a weakened immune system, for example, you're taking immunosuppressant medicines or you have HIV have symptoms affecting your eyes To avoid toxoplasmosis: wear gloves while gardening, and wash your hands thoroughly afterwards wash your hands before preparing food and eating wash hands, knives and chopping boards thoroughly after preparing raw meat wash fruit and vegetables thoroughly to get rid of any traces of soil thoroughly cook meat, especially lamb, pork and venison avoid cat poo in cat litter and soil if you can, wearing gloves if you need to empty cat litter trays and washing your hands afterwards Don't: eat raw or undercooked meat, or cured meats like salami or parma ham have unpasteurised goats' milk or any products made from it touch pregnant sheep or lambs do not feed cats raw or undercooked meat
