Experts say more research is needed into a disease spread by cats after figures show an estimated 350,000 people a year in the UK become infected with toxoplasmosis.
Although only a minority of people - between one and two in every 10 - has symptoms, advisers say extra measures to control the disease may be needed.
The disease is spread by direct contact with cats or eating contaminated food.
The Food Standards Agency has released an official report.
Cat owners are assured that the risks can be managed with good basic hygiene and common sense.
British Veterinary Association past president and veterinary surgeon Harvey Locke said: "The biggest threat is to pregnant women and those who are immuno-compromised, which we have known for some time. It is useful to reiterate that they should take extra care but there is no need for people to get rid of their pet cats or choose not to have cats as pets."
The report says there is a lack of data on the condition, making it difficult to estimate the real burden of the disease.
And it says the current consumer advice should be reviewed.
FSA chief scientist Andrew Wadge said: "This thorough and detailed report points out key gaps in our knowledge about this parasite and suggests areas where more research is needed which will help us in estimating how much infection is due to food and which foods might be the highest risk.
"The report also suggests we look again at our advice to vulnerable groups and ensure that it reflects current scientific knowledge."
In about 80% of cases, a person who is infected will not be aware and will have no symptoms.
Others will develop mild flu-like symptoms, but will not need treatment.
But toxoplasmosis - the disease in humans - can cause serious complications in people with weakened immune systems, such as those with HIV and cancer.
And in pregnant women it can result in the baby being born blind or with brain damage. Three babies in every 100,000 are born with the condition in the UK.
Toxoplasmosis is a notifiable disease in Scotland but is neither a notifiable nor reportable disease in the rest of the UK.
The culprit parasite, Toxoplasma gondii, can get into the food chain via cats faeces causing contamination of soil, water and plants.
Humans may catch the infection from eating undercooked meat from animals harbouring toxoplasma or from contact with cat litter or contaminated soil.
Once infected, a person is immune from further infection for life.
The best way to avoid infection is to make sure you wear gloves when gardening or changing your cat's litter tray, wash fruit and vegetables before eating and cook meat thoroughly - although it is possible to still enjoy it rare, says the Food Standards Agency.
Pregnant women should also avoid contact with sheep and newborn lambs during the lambing season because there is a small risk that an infected sheep or lamb could pass the infection on at this time.