Week 3 Role of mosquito II - West Nile disease Flashcards
What are the diseases caused by West Nile virus?
West Nile fever, West Nile encephalitis, West Nile meningitis, West Nile meningoencephalitis, West Nile poliomyelitis
What is the vector of West Nile virus, mode of transmission and common reservoir?
Mosquitoes, primarily Cullex species
Bite of infected mosquito, blood transfusion or organ donation, mother to child transplacentally or during breast feeding
Wild birds
What are the symptoms of West Nile fever ?
Fever Chills Severe frontal headache Pain in the eyes upon movement Fatigue Vomiting Lymphadenopathy Non-itching skin rash
Facts of West Nile fever
West Nile fever is typically self-limiting, can last several days-weeks and there’s no long-term sequelae
Asymptomatic infection in about 80% of infections
West Nile fever is responsible for about 20% of infections
What diseases are caused by the neuroinvasive form of West Nile virus?
Encephalitis
Menengitis
Poliomyelitis
Facts of neuroinvasive form of West Nile virus
50% will have long-term neurological sequelae
>50 years of age
causes immunosuppression
Symptoms of West Nile meningitis
Inflammation of the meninges Abrupt fever Severe headache Sensitivity to light and sound Has a rate of 2% mortality in US
Symptoms and facts of West Nile encephalitis
targets people with >50 years
can cause Confusion, Tremors, Abnormal movements and Coma
Long term sequelae Fatigue Headache Decreased attention span Apathy Depression
Symptoms and facts of West Nile poliomyelitis
Not limited to elderly Acute flaccid paralysis Damage to the spinal cord Muscle weakness in limbs Breathing muscles can be affected Quadriplegia Respiratory failure can occur
What are the diagnose, treatment and prevention of West Nile poliomyelitis?
Typically immunological (ELISA or similar)
Supportive care
Vector control
History of West Nile poliomyelitis
1937 – First reported in Uganda
1957 – First report of neuroinvasive disease in Israel - 1990s – Neuroinvasive disease was uncommon until several outbreaks of severe disease were reported
West Nile poliomyelitis entered US in 1999 probably by transport of infected mosquitos in cargo ships, Air travel, Wind and Transport or migration of infected birds
It’s genetically similar to an Israeli strain found on
62 human cases
It entered bird populations and has High mortality
2000 – 21 human cases in New York
Evidence of bird infections from Vermont to S. Carolina
2001 – 66 human cases
First detected WN02 genotype
2002 - >4000 human cases
2003 - >9800 human cases
Peak in human cases
2004 – nearly all states in continental US
How climate change influences the incidence of West Nile poliomyelitis
Increased temperature can shorten extrinsic incubation period and alter development rate and survival of mosquito as well as alter precipitation pattern, it also gets complicated by urban environments
Precise timing is more important than total amount
