Causative agent, transmission, symptoms, pathogenesis, diagnosis, treatment, control,zika

1. TRANSMISSION
Mosquito-borne : Aedes aegypti
Sexual contact
Blood products
Organ transplantation
From pregnant mother to fetus
Infected animals
Incubation: 3-14 days
ZIKA
SYMPTOMS
Mostly asymptomatic or mild symptoms
Symptoms last for 2-7 days
Fever, headache, rash, conjuctivitis, Muscle and Joint pain,
malaise, Lymphadenopathy
Complications
Zika during pregnancy causes
• microencephaly (head is smaller than normal due to
abnormal brain development).
• Congenital abnormalities ( physical disability, heart
defects, hearing defect)
• Pregnancy complications such as fetal loss, stillbirth, and
preterm birth.
• Guillain-Barré syndrome ( immune system attacks the
nerves leading to weakness, paralysis)
• Neuropathy and myelitis, particularly in adults and older
children.
• No reported cases of death
TREATMENT
• No specific medicine
• Use pain relievers with acetaminophen and avoid medicines
with aspirin, which could worsen bleeding.
• Take rest, drink plenty of fluids
CAUSATIVE AGENT
Zika virus (Flavi virus)
Affects humans and non human primates( monkeys
and apes)
DIAGNOSIS
• Based on Symptoms
• Blood/ urine/ semen/ saliva/ CSF/ amniotic fluid
• Blood test to check for the virus or antibodies
• Nucleic Acid Testing (NAT)
• Detection of IgM antibodies
CONTROL
• Vector control
• Avoid travelling to tropical areas/ sub tropical areas in times of outbreak
PATHOGENESIS
ZIKV replicates in epithelial lining of midgut and salivary cells of the
vector. After 5 days, it appears in the mosquito saliva. During blood
meal, the vector inoculates the virus into human host skin.
The virus then infect the epidermal keratinocytes, fibroblast and the
Langerhans cells.
Viraemia ensues and the primary target for of ZIKV is monocytes.
Monocytes have the potential to infiltrate immune sanctuary sites
such as the brain, testes and placenta.
Following viral transmission, viral attachment to the host cellular
receptors is facilitated by E glycoprotein.
This is followed by endocytic uptake, uncoating of the nucleocapsid
and viral RNA are eventually released into the cytoplasm. In stark
contrast to other flaviruses, its antigen has been demonstrated in
host cell nucleus.