Roane Viruses Flashcards
measles has a deficiency in what
Vitamin A
Infections involving the skin: three routes
1 Direct Inoculation (Papillomavirus, Poxviruses except smallpox, virus and primary HSV).
2 Local Spread from an Internal Focus (Recurrent HSV and VZV). S
3 ystemic Infection (Primary VZV, Rubella virus, Measles virus, and B19 parvovirus).
Measles epidemiology:
what group?
What time of year?
Measles is most prevalent in children 5 to 10 years of age and is seen primarily during the winter and spring.
incubation period for measles
The incubation period is 10 to 11 days. Theprodromal phase (3-4 days)
symptoms of measles
high fever, cough coryza, conjunctivitis, malaise,mucosa inflammation.
An erythematous macular and papular rash then develops behind the ears and over the forehead, spreading to the face, neck, trunk and extremities within 3 days. The lesions tend to reach confluence over the face and upper back, at which time the fever, cough and conjunctivitis are most severe. Koplik’s spots disappear 2 to 3 days after the appearance of the rash. Uncommon complications include encephalitis and purpura. SSPE is a rare but usually fatal complication.
How do skin lesions result
Skin lesions may result from the direct effect of viral multiplication (cell damage or cell death) or may result from the host response to the virus. Skin lesions of rubella and measles are thought to be at least partly due to the cell-mediated immune response to the virus. There is evidence for its direct attack of measles virus-infected endothelial cells by specific T-lymphocytes. Alternatively, the rash of Fifth Disease which is caused by B19 parvovirus is the result of immune-complex formation. These antigen-antibody complexes accumulate in the skin.
- Picture of a teen with measles: started behind the ears spread to the throat and then went all over, this picture is showing you the systemic spread
Rubella incubation
The incubation for this disease is 14 and 21 days following exposure to the virus
rubella symptoms
The prodromal symptoms can consist of low gradefever, headache, conjunctivitis, cough, sore throat and marked lymphadenopathy, arthritis can be seen in adults. From 1 to 4 days after initiation of the prodrome, an erythematous macular to papular rash appears, first on the face and then on the neck, trunk and extremities. The rash usually clears after 2 to 3 days.
When is rubella most common
spring months
rubella complications common in
intrauterine infections produces congenital malformation in 50% of neonates.
The earlier during pregnancy the infection occurs, the more severe the teratogenic findings. A wide variety of systems can be affected, especially the heart, eyes, auditory system, bones and CNS.
rubella
Rubella
parvovirus
most important parvovirus
B19
- Fifth disease: B19 infects the progenitor cells and an immune response occurs where you have a high antibody to viral ration è immune complex formation and these will accumulate in the skin (rash) or joints (arthritic like condition),
- Transient aplastic crisis – is a disease where B19 infects a lot of progenitor cells and a tremendous amount of viruses are made in a short time before the immune system can attack or kick in è viral excess è transient aplastic crisis where RBC aren’t produced and can die if don’t get transfusion
- No antibody is produced in the infected host and the virus persists for an extended period of time called pure red blood cell aplasia, if you give commercial IgG to try and shut down the virus giving partial recovery, likes the red blood cell because it has the P antigen
B19
B19
- Fetal: hydrops fetalis- [A severe form of the genetic disorder thalassaemia in which all four alpha chain polypeptides making up the haemoglobin molecule (the protein which transports oxygen in the body) are missing due to a defect in the gene which codes for them. As a result, affected individuals die at or before birth.] infect the fetus , erythroid progenitor cells found in the liver and they are infected, some evidence that myocardial and bone marrow may be infected, baby doesn’t develop normally, they have edema all over the body,
- congenital pure red blood cell aplasia- fetus is infected during development and the bone marrow and liver infected, if give a transfusion may fix it, RBCs fail to be made, result of autoimmunity or immune toleranceèviral persistent
Treatment considerations for monkey pox
An arm showing Ebola lesions. The dark purple bruise like lesions give way to blood filled blisters of highly infectious fluid.
Describe the major skin disease that are caused by HSV-1
1 causes a disease called Herpes labialis (Figure 1). This disease is actually the result of reactivation of a latent infection.- trigeminal nerve , seen in corner of the mouth
can cause other manifestations, for example, herpes gladiatorum which occurs in wrestlers as a result of direct skin to skin contact.
Eczema herpeticum is a manifestation of HSV – 1 infection in patients with skin disorders such as atopic dermatitis, pemphigus, or Darier’s disease. This herpes infection is shown in Figure 5.
Disease caused by HSV 2
– 2 causes primary and recurrent genital herpes. An example of primary genitalisis presented in Figure 2.
sacral ganglia
Varicella Zoster virus (HHV– 3) causes what disease
causes a primary infection in children and adults known as chickenpox. This infection can be very painful in adults.
Zoster (shingles)
the result of successful reactivation of latent infection in dermatomes of immunocompromised patients (AIDS, chemotherapy, etc.). This is a very painful condition.
dorsal root ganglion
disease caused by HHV-6
causes the most common childhood exanthem known as roseola infantum (exanthema subitum/sixth disease).
Human herpesvirus – 8 (HHV-8) causes what disease
Kaposi sarcoma in AIDS patients. An examples of scrotal lesions caused by HHV-8 is shown in
Note: Herpes virus B (monkey herpesvirus) causes highly fatal encephalitis that results from a bite by the infected monkey.
