Akhir 25, 1432 / March 30, 2011, SPA -- Bolivia's Health Ministry Tuesday called on its people to keep vigilant against any symptoms of dengue after 23 fatalities and 4,000 cases of infection were reported nationwide in recent days. Most cases have concentrated in the Amazon region of the South American country, with the highest numbers registered in the provinces of Beni and Santa Cruz, Xinhua quoted Health Minister Nila Heredia as saying. In the Santa Cruz province alone, 11 of the 23 fatalities and some 1,200 cases were reported, Heredia said. At the main children's hospital in Santa Cruz, there has been a daily admission of up to 50 new dengue cases this week, Heredia said. Health authorities have alerted local information networks to call on mothers of infants and young children who are particularly vulnerable to dengue to swiftly report to the nearest hospitals if their infants and children have any dengue symptoms. All Bolivians are also urged not to treat any suspected cases at home nor take any over-the-counter drugs. They were advised to consult doctors at the nearest hospitals once such symptoms emerge. Hot and humid tropical weather in the Amazon region provides optimal conditions for mosquitoes to thrive and spread dengue. Once infected with the epidemic, people get symptoms such as high fever, headache and vomiting, which can be deadly unless patients are treated in a timely way.