What is Yellow Fever in Children?
Yellow fever is an acute vector-borne (transmitted by blood-sucking arthropod) infectious disease of a viral nature that is common in the tropical regions of South America and Africa, and manifests itself as hemorrhagic syndrome, jaundice and nephropathy.
Types of yellow fever in children:
- city;
- forest;
- unspecified.
Epidemiology
Yellow fever (VL) is spread by wild animals and sick people. Among wild animals, the reservoirs of the virus are hedgehogs, anteaters, sloths, monkeys, etc. The mosquitoes also transmit the infection. The susceptibility to the disease is universal. The disease is manifested by epidemic outbreaks.
A child can become infected if the blood of a patient or a person who has died of yellow fever (VL) has got on his mucous membranes or damaged skin. About 3-6 days pass from infection to the onset of symptoms.
Classification
Yellow fever, which takes place in a typical form, has cycles. There are three of them. The first is the initial, febrile period, this is the phase of hyperemia. The second – the period of a drop in temperature, the weakening of the disease – this is the phase of remission. The third is the period of venous stasis.
Clinical forms
There are three clinical forms, they differ in the severity of the manifestations of the disease. The mild form is manifested by transient fever, headaches. The moderate form of yellow fever is manifested by headache, fever, nausea, nosebleeds, while positive vascular tests, slight proteinuria, subclinical rise in bilirubin, back pain, epigastric pain, vomiting, dizziness, photophobia are recorded. In severe form, severe headache, fever, intense vomiting, back pain, oliguria, jaundice are manifested. There is also a malignant form of yellow fever in children, in which the child has hypothermia, bloody vomiting, jaundice, hemorrhagic syndrome, shock or coma.
Causes of Yellow Fever in Children
The causative agent is a group B arbovirus from the family Togaviridae. Guinea pigs, monkeys, and bats are susceptible to it.
Pathogenesis during Yellow Fever in Children
The virus is initially based in regional lymph nodes, where it multiplies during the incubation period. After this, the VL virus enters the circulatory system, viremia lasts 2 days. It spreads through the blood, reaching the kidneys, liver, bone marrow, spleen. In a sick child, the development of DIC occurs (disseminated intravascular coagulation), as with other hemorrhagic fevers).
Pathomorphology
The liver is maximally altered (hepatocyte necrosis occurs with the formation of Kaunsilmen’s bodies). An increase in the kidneys is observed, they become yellowish, fatty degeneration is visible in the section.
Examinations revealed multiple hemorrhages in the lungs, gastrointestinal tract, pericardium, hemorrhage and perivascular infiltrates in the brain.
Symptoms of Yellow Fever in Children
The disease has an acute onset, the temperature reaches 40–41 ° C. The face with redness, puffy, fixed hyperemia of the neck and upper chest, swelling of the lips. Also, patients complain of headache and muscle pain. For the onset of the disease, the following symptoms are characteristic: nausea and vomiting with blood, severe hemorrhagic syndrome, bleeding gums, jaundice, hypotension, impaired consciousness, delirium, severe kidney damage, collapse. With kidney damage, proteinuria, anuria, bile pigments, cylindruria, azotemia occur. Fatal outcomes occur on the 6-7th day of illness due to uremic or hepatic coma.
Diagnosis of Yellow Fever in Children
Yellow fever in children is determined using specific diagnostics – the methods of CSC, PH, RTGA, ELISA with the separate determination of specific antibodies of classes TgM and IgG.
Treatment for Yellow Fever in Children
Specific therapy for yellow fever in children has not been developed. Apply symptomatic treatment with antipyretics, analgesics, antiemetics. Also, symptomatic treatment includes the fight against shock, hemorrhagic syndrome.
Prescribe the antiviral drug ribavirin. In the process of treatment, serious monitoring of blood counts is necessary, since taking the drug can lead to dose-dependent hemolytic anemia, and ultimately to death. Infusion therapy is also performed to treat yellow fever in children.
Prevention of Yellow Fever in Children
Preventive measures begin with strict epidemiological surveillance in the territory where cases of yellow fever (VL) are recorded. Routine extermination of mosquitoes that carry the virus should be carried out. Vehicles arriving from epidemic sites must undergo pest control. Prevention includes the use of individual and collective mosquito repellents, quarantine isolation of people who are not immunized against yellow fever (VL), arriving from places where there are cases of the disease, immunization of the population against this disease.
Vaccination
Yellow fever vaccine is an attenuated live virus of strain ND grown on chicken embryos. 1 dose of the vaccine (0.5 ml) contains at least 1000 LD50 of the virus, as well as trace amounts of chicken egg protein and neomycin or polymyxin.
A single dose is administered under the skin to children over 9 months of age who travel to countries where there are yellow fever epidemics. After vaccination, an intense immunity is formed in the body for 10 years or more. Doctors decide revaccination based on individual cases.
In theory, revaccination is indicated only for seronegative children and adults, but if screening for specific antibodies is not possible, doctors decide to re-vaccinate, especially if the interval between vaccinations is more than 10 years.
Yellow fever vaccine in children almost never causes allergies. Only in extremely rare cases do moderate fever, myalgia and malaise occur.
Contraindications are the same as with the introduction of other live vaccines: immunodeficiencies, pregnancy, immunosuppressive therapy, severe allergic reactions to egg white, neomycin or polymyxin.