Human herpesvirus-6 infection
Introduction
Introduction to human herpesvirus-6 infection Human herpesvirus-6 (HHV-6) was first isolated from lymphocyte proliferative diseases and peripheral blood lymphocytes of patients with AIDS by Salahnddin and Csvlo of the National Cancer Institute in 1986. The virus mainly infects humans. T cells, which are similar in morphology and biologicality to herpesviruses, were named human herpesvirus-6 (HHV-6). basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Infection: The virus is excreted in saliva, tracheal secretions and urine, and the child is infected by close contact with the parents. Complications: baby rose rash
Cause
The cause of human herpesvirus-6 infection
Causes:
HHV-6 is an enveloped virus with a icosahedral nucleocapsid wrapped with linear ds-DNA. The HHV-6 genome has some homology with other herpesviruses, but serologically There are differences. HHV-6 infection is spread all over the world. Like other herpes viruses, people have acquired primary infections in early childhood, and adults are generally infected.
Pathogenesis:
The virus is excreted in saliva, tracheal secretions and urine, and the child is infected by close contact with the parents. At the age of 2, the detection rate of HHV-6 antibody is 90% or higher, and when it is 30 to 40 years old, it is Down, only 60% of adults over the age of 40 have HHV-6 antibodies.
When the disease occurs due to the primary infection, the child develops acute febrile rose rash. After that, the virus enters the latent infection state in the body, and the gene combination exists in the form of integrated peripheral blood lymphocyte chromosomes. When the body immunity is low, the latent virus is Activation, how the virus enters the latent state and the mechanism of activation is unclear. HHV-6 mainly infects CD4 T cells and up-regulates CD4+ T cell expression. In addition, HHV-6 can also infect CD8+ T cells, NK cells, and giants. Phagocytes, large mononuclear cells, etc., thereby destroying the body's antiviral cellular immunity.
Prevention
Human herpesvirus-6 infection prevention
Because the source of infection is widespread and mostly recessive, the transmission route is complicated and difficult to control, and the population is generally susceptible, it is difficult to prevent HHV-6 infection. The focus of prevention is to develop an effective vaccine.
Complication
Complications of human herpesvirus-6 infection Complications, baby, rose
Herpes infection can be followed by bacterial infections, which can aggravate clinical symptoms.
(1) Herpetic keratitis is one of the common causes of blindness. In general, herpetic keratitis is as follows:
1. There is often a history of cold or fever before onset.
2. Photophobia, tearing, foreign body sensation or eye pain, vision loss.
3. Dendritic keratitis: ulcers are dendritic or coral-like.
4. Map-like keratitis: expanded by dendritic ulcers.
5. Discoid keratitis: opacity and edema in the central cornea, the epithelium is almost intact.
(2) Genital herpes may cause psychogenic and organic sexual dysfunction in patients.
(3) Intrauterine infection can cause premature birth, or congenital malformation.
Congenital malformation is a morphological or structural anomaly that exists at birth.
Symptom
Human herpesvirus-6 infection symptoms Common symptoms Nausea papules Hyperthermia herpes Herpes Lymph node swelling Sleeping convulsions Congestive rose rash
Infant infection
HHV-6 infection is usually asymptomatic, and the original infection of infants or immunodeficiency patients can have obvious symptoms. Most of the primary infections occur in children from 6 months to 2 years old. In severe cases, infantile rose rash (the sixth disease) ), often sudden onset, accompanied by high fever (39 ~ 40 ° C), after 3 to 5 days, the heat plummeted, body temperature fell to normal within 24h, hot red rash or maculopapular rash appeared, usually first occurred in the neck The body and the trunk are spread to the limbs, and there are no rashes on the cheeks, elbows, knees and palmars. After 1 to 2 days, the rash disappears without leaving any traces. The child is usually in good condition and can be accompanied by the pharynx. Congestion and neck lymphadenopathy, severe cases can occur high fever, convulsions, nausea, vomiting, lethargy and other systemic symptoms.
2. Adult infection
HHV-6 antibody-negative adult and older children with HHV-6 primary infection may develop mononucleosis, manifested as fever, bilateral cervical lymphadenopathy, no tenderness, lasting 1 to 3 months The rash is mostly rash, the color is bright red, can be fused into a piece, and even develops into diffuse erythema. The desquamation is more obvious when the regression occurs, and the peripheral blood mononuclear cells increase significantly, accounting for 40% to 60% of the total number of white blood cells, sometimes visible. Lymphocytes.
3. Infection of immunodeficient patients
Organ transplants and AIDS patients are more susceptible to HHV-6 than normal people. The virus is activated from the latent state, replicates, invades human T cells and develops disease, clinically visible fever, leukopenia, rash, and even pneumonia, hepatitis and encephalitis.
Examine
Examination of human herpesvirus-6 infection
1. HHV-6 is isolated and cultured from peripheral blood lymphocytes, or HHV-6 DNA can be detected by PCR.
2. The serological specific test mostly uses indirect immunofluorescence and immunoenzymatic methods. The specific IgG and IgM of HHV-6 can be detected within 7 days after onset.
Diagnosis
Diagnosis and diagnosis of human herpesvirus-6 infection
It is not difficult to diagnose the disease according to the typical clinical manifestations. Laboratory tests can assist in the diagnosis. In vitro immunofluorescence and immunoenzymatic methods are used for serological specific tests. HHV-6 specific IgG and IgM are within 7 days after onset. It can be detected that HHV-6 is isolated and cultured from peripheral blood lymphocytes, or HHV-6 DNA can be detected by PCR.
