Yellow fever

Yellow Fever: Symptoms, Treatment and Prevention

Yellow Fever is an acute viral disease transmitted by mosquitoes, which is characterized by fever, severe intoxication, thrombohemorrhagic syndrome, liver and kidney damage. This is a quarantine disease that can lead to serious complications and even death. In this article, we will look at the etiology, pathogenesis, symptoms, treatment and prevention of yellow fever.

Etiology and Pathogenesis

Yellow fever is caused by an arbovirus, which is transmitted through mosquito bites. The virus is quickly inactivated at high temperatures and under the influence of disinfectants, but persists for a long time in the frozen state and when dried. The virus enters the human body when bitten by an infected mosquito, spreads from the site of introduction along the lymphatic tract and reaches regional lymph nodes, where it multiplies and accumulates. After a few days, the virus enters the blood, hematogenously, into various organs (liver, spleen, kidneys, bone marrow, lymph nodes), causing their damage. After an infection, intense immunity develops and persists for 6-8 years.

Symptoms and Course

The disease begins suddenly with the appearance of a severe headache, severe pain in the lower back, back, and limbs. By the end of the first day, body temperature reaches 39-40 °C and higher. Hyperemia and puffiness of the face, swelling of the eyelids, injection of blood vessels in the sclera and conjunctiva appear. The pulse quickens to 100-130 per minute. On the 2nd day of the disease, painful thirst, nausea, and repeated vomiting, first of mucus and then of bile, appear. The mucous membrane of the oral cavity is hyperemic, the tongue is dry, the edges of the tongue are red. Towards the end of the initial febrile period (stage of hyperemia), on the 3-4th day of illness, cyanosis, jaundice, and a slight admixture of blood in the vomit may appear.

On the 4-5th day of illness, the patient’s health worsens, body temperature drops to low-grade (remission stage). However, after a few hours, the body temperature rises again, the patient’s condition progressively worsens, signs of damage to the central nervous system appear (dizziness, convulsions, delirium, decreased consciousness), as well as symptoms of liver and kidney damage (jaundice, increased levels of bilirubin in the blood, impaired renal function ). In severe cases, thrombohemorrhagic syndrome may develop, accompanied by bleeding, a decrease in the number of platelets and an increase in blood clotting time.

Treatment and Prevention

Treatment of yellow fever is based on symptomatic therapy aimed at improving the patient’s well-being and reducing the severity of symptoms. Blood loss must be compensated by administering blood substitutes and antithrombin drugs. To normalize liver and kidney function, hepatoprotectors and diuretics are used. In severe cases, admission to the intensive care unit may be required.

Prevention of yellow fever is based on measures to combat mosquitoes that carry the virus and vaccination. Yellow fever vaccine is recommended for all people planning to travel to endemic areas where the disease is common. Vaccination is carried out 10 days before departure and provides lasting immunity for 10 years. In addition, to prevent yellow fever, it is necessary to take measures to protect against mosquito bites (use repellents, wear protective clothing, use mosquito nets, etc.).