The bugs tend to feed at night, preferring moist surfaces near the eyes or mouth. A triatomine bug can become infected with T. cruzi when it feeds on an infected host. T. cruzi replicates in the insects intestinal tract and is shed in the bugs feces. When an infected triatomine feeds, it pierces the skin and takes in a blood meal, defecating at the same time to make room for the new meal. The bite is typically painless, but causes itching. Scratching at the bite introduces the T. cruzi-laden feces into the bite wound, initiating infection.In addition to classical vector spread, Chagas disease can be transmitted through consumption of food or drink contaminated with triatomine insects or their feces. Since heating or drying kills the parasites, drinks and especially fruit juices are the most frequent source of infection. This oral route of transmission has been implicated in several outbreaks, where it led to unusually severe symptoms, likely due to infection with a higher parasite load than from the bite of a triatomine bug.T. cruzi can be transmitted independent of the triatomine bug during blood transfusion, following organ transplantation, or across the placenta during pregnancy. Transfusion with the blood of an infected donor infects the recipient 10–25% of the time. To prevent this, blood donations are screened for T. cruzi in many countries with endemic Chagas disease, as well as the United States. Similarly, transplantation of solid organs from an infected donor can transmit T. cruzi to the recipient.
Ethinylestradiol/norethisterone (EE/NET), or ethinylestradiol/norethindrone, is a combination birth control pill which contains ethinylestradiol (EE), an estrogen and norethisterone (NET), a progestin. It is used for birth control, symptoms of menstruation, endometriosis, and menopausal symptoms. Other uses include acne. It is taken by mouth. Some preparations of EE/NET additionally contain an iron supplement in the form of ferrous fumarate.Side effects can include nausea, headache, blood clots, breast pain, depression, and liver problems. Use is not recommended during pregnancy, the initial three weeks after childbirth, and in those at high risk of blood clots. It, however, may be started immediately after a miscarriage or abortion. Smoking while using combined birth control pills is not recommended. It works by stopping ovulation, making the uterus not suitable for implantation, and making the mucus at the opening to the cervix thick.This combination pill was approved for medical use in the United States in 1964. It is on the World Health Organizations List of Essential Medicines. It is available as a generic medication. It is marketed under a large number of brand names. In 2020, it was the 45th most commonly prescribed medication in the United States, with more than 14 million prescriptions. See also
Mestranol/norethisterone
Oral contraceptive formulations
List of combined sex-hormonal preparations


== References ==