Sexually Transmitted Infections (STIs or STDs) can be caused by about 30 types of bacteria, viruses and known parasites, which are spread through the practice of sexual relations between people.
Of these thirty, the WHO has linked 8 with the highest incidence of diseases . And of those 8 infections, 4 are currently curable: syphilis, gonorrhea, chlamydia, and trichomoniasis. It is estimated that, annually, about 357 million people contract one of these. The remaining 4 (hepatitis B, herpes, HIV and HPV) are incurable viral infections that can be mitigated or attenuated with treatment.
STDs generally affect both men and women. However, there are exceptions, and some of them do make a gender differentiation. All these pathologies can lead to chronic diseases , complications (especially during pregnancy), some types of cancer and even , in the worst case, death.
As discussed, STDs are transmitted sexually, including vaginal, anal, and oral sex. They can also be spread by non-sexual means , such as blood transfusions or from mother to fetus.
People can be carriers of any of these diseases without realizing it , since in many cases, the symptoms are mild or we do not directly experience any type of affection, and we act merely as transmitters of the pathology.
Despite the fact that we live in the information age and have great sources of knowledge , STDs continue to grow , especially among the youngest. It is estimated that in Spain , cases of syphilis and gonorrhea are the pathologies that have increased the most , with an incidence rate of almost 55% in young people between 20 and 24 years of age. The Spanish Society of Contraception , ensures that this is due to a ‘relaxation’ of the population in the use of effective contraceptive methods , such as the condom. In general terms, the WHO estimates that more than one million people contract a sexually transmitted disease every day .
In the following gallery we review the different types of STDs and tell you what each of them consists of, relying on experts from the World Health Organization (WHO).





