A 35-year-old forestry officer was delivered to the hospital on the 7th day after the onset of the disease. He complains of chills, elevated body temperature up to 40.0°C, sharp headache, and myalgias. On examination his face is puffy and hyperemic, the tongue is dry, "chalk-dusted": In the left inguinal area, a sharply painful conglomeration of enlarged lymph nodes can be palpated. The skin over the conglomeration is hyperemic and tense. What etiotropic therapy should be prescribed to this patient?