The sexually transmitted disease chlamydia has been strongly linked to cervical cancer in a study carried out by scientists in Finland. Chlamydia trachomatis accounted for 24,311 new infections in men and 32,544 in women in 1999. However, because most cases show no symptoms, the actual number could be 90% greater. The study, published in the Journal of the American Medical Association, found that women infected with the chlamydia strain serotype G were nearly seven times more likely to develop cervical cancer (JAMA. 2001 285:47-51). Another two strains increased the risk of disease by nearly four-fold and three-fold. Also, exposure to more than one strain raised the overall risk. Dr Tarja Anttila from the National Public Health Institute and Dr Jorma Paavonen from the University of Helsinki analysed blood tests taken from 530,000 women in Finland, Norway and Sweden. One hundred and twenty-eight of the women developed invasive cervical cancer at least 12 months after donating a sample. The researchers then looked for an association between the presence of antibodies, identifying 10 different chlamydia strains, and the development of squamous cell carcinoma. The Public Health Laboratory Service (PHLS) reported that the number of diagnosed infections has risen by 76% since 1995. These findings underline the need for widespread screening of chlamydia infection. A spokesman for the PHLS commented, "It is very important that people understand that chlamydia is associated with all sorts of long term side effects."