Neglected tropical diseases 3 Flashcards
What % of reported rabies infections are in children?
40%
Which communities are mainly affected by rabies?
Poor rural communities in asia and africa
What causes rabies?
Lyssavirus
How is rabies transmitted?
Via saliva from infected animals i.e. dogs
What % of human cases of rabies are caused by dog bites?
99%
How does rabies affect the brian?
Causes inflammation
What are the two types of rabies?
Furious and paralytic
Treatment of rabies?
Thorough washing of would
Rabies prevention?
Active vaccination of humans and dogs
Passive immunisation: immunoglobulins against lyssavirus can be used as an “antidote”
What is on the outside of lyssavirus particles?
Glycopeoteins
Lyssavirus shape?
Bulleted structure
What is inside lyssavirus?
helical ribonuclease protein
What is the target of virus neutralising antibodies used for passive immunisation of rabies?
Glycoproteins on the surface
How is lyssavirus adapted for replication in the mammalian CNS?
Glycoproteins on its surface
How do the glycoproteins on the surface help lyssavirus replicate in the mammalian CNS?
They bind to receptors found specifically on nerve cells, e.g. nicotinic ACh receptor and low affinity nerve growth factor receptors, and ganglyocytes
Incubation period of lyssavirus?
1-3 months
What occurs during lyssavirus incubation period?
Virus replicates in the muscle
Symptoms during incubation of lyssavirus?
None, fever, vomiting, loss of appetite, headaches
At which nicotinic ACh receptors does lyssavirus bind to?
Those at the neuromuscular junction
Where does the virus go after binding to the neuromuscular junction?
Travels up the axons of peripheral nerves, into neurons of the CNS, the brain and the SC
What happens after lyssavirus enters the SC and brain?
It replicates in the motor neurons
What happens as a result of lyssavirus replicating within the motor neurons of the brain and SC?
Neuronal damage, dysfunction and inflammation
Final step of lyssavirus infection?
Infection spreads along cranial nerves into salivary glands, skin, cornea and other organs
What causes the excessive salivation seen in furious rabies?
Infection of salivary glands
When are negri bodies seen and what is their appearance?
Small darker spots seen in staining
What are negri bodies?
Abnormal structure in the nucleus or cytoplasm composed of protein
Composed of viral N and P proteins
Result of accumulation of large quantities of protein
What can be used to confirm rabies post-mortem?
Direct fluorescence antibody test
%s of the two types of rabies?
furious–> 80%, paralytic–> 20%
Presentation of furious rabies?
Hyperactivity and hydrophobia, death after a few days
Presentation of paralytic rabies?
Gradual muscle paralysis, slow develop of coma, death
What is encephalitis?
Inflammation of the brain
Theories as to why rabies leads to two diff presentations?
Type of animal vector, wound site, incubation period, history of rabies vaccine
Main infection sites for furious rabies?
Function of anterior horn of spinal cord is disrupted, cells damaged
Main infection sites for paralytic rabies?
Peripheral nerves are demyelinated (muscle weakness)
