Sunday, June 24, 2018

Nipah Virus (NiV) Disease Control Guideline

In Nepal, Epidemiology and Disease Control Division (EDCD) give the Infectious Disease Control Guideline for Nipah Virus.

Disease name: Nipah virus (NiV) disease
ICD-10 code: ICD-10 B 33.8
Epidemiology:
Background/causative agent: Nipah viral disease is one of the zoonotic infections caused by Nipah virus, a member of the family Paramyxoviridae, genus Henipavirus. It was first identified and isolated in Malaysia in 1999 during the outbreak of encephalitis and severe respiratory illness among pig farmers and people with close contact with the pig. The virus was named after Sungai Nipah, a village in Malaysia Peninsula. Another outbreak occurred in Bangladesh in 2001 and repeated outbreaks have been reported there since then. The outbreak in Siliguri, India occurred in 2001 with reports of human-to-human transmission in hospital settings.
Incubation period: 5-14 days
Reservoir: Fruit bats members of genus Pteropus are the major reservoirs. Pig is an intermediate host but infected cows, goats and dogs have been reported
Transmission: 3 known pathways
1. Drinking of contaminated fresh date palm sap majority of cases in Bangladesh
2. Via direct contact with infected bats, pigs, or from other NiV infected people’s secretions.
3. Direct contact with NiV-contaminated fruit bat secretions
Risk groups: All age groups are susceptible. People who come in close contact with infected swine are at increased risk.
Clinical features: Manifestations of NiV infection range from asymptomatic infection to acute respiratory illness to fatal encephalitis.
1. The patient may present with influenza-like symptoms- fever, headache, myalgia, vomiting and sore throat.
2. Neurological symptoms- Drowsiness, dizziness, seizures, followed by altered mental status and neurological deficit (encephalitis). These may progress into coma and death within 24-48 hours. Majority of patients who survive will have full recovery but 20% of cases will have the neurological deficit.
3. Some patients present with pneumonia leading to ARDS
Diagnosis: Diagnosis can be established in a patient with the clinical history suggestive of NiV by direct virus isolation or polymerase chain reaction(RT-PCR) in blood, CSF, throat and nasal swabs and urine at the early stage of infection. At a later stage, antibody (IgM and IgG) can be detected by ELISA. In fatal cases, tissues (eg. brain, spleen) can be used for virus isolation, RT-PCR and immunohistochemistry.
Differential diagnosis: Other causes of encephalitis and severe respiratory illness need to be considered.
1. Viral encephalitides e.g. Herpes simplex encephalitis, Japanese encephalitis (JBE),
2. Bacterial meningitis
3. Cerebral malaria
4. Influenza and influenza-like illness
Case fatality rate: 40-75%; variation in different outbreaks
Case definition 
Suspected case: A person fulfilling both of the following criteria.
1. Features of acute encephalitis:
a. Acute onset of fever AND
b. Evidence of acute brain dysfunction manifested as
i. Altered mental status OR
ii. New onset of seizures OR
iii. Any other neurological deficit
2. Epidemiological linkage.
a. Drinking raw date palm sap OR
b. Occurring during Nipah season OR
c. Patient from Nipah endemic area
Probable case: A person with features of acute encephalitis
a. during a Nipah outbreak in the area OR
b. with history of contact with confirmed Nipah patient
Respiratory features may present in patients with suspected or probable cases with or without encephalitis. The respiratory features are
a. Onset of illness < 7 days duration AND
b. Acute onset of fever AND
c. Severe shortness of breath, cough AND
d. Chest radiograph showing diffuse infiltrates confirmed case A suspected or probable case of Nipah virus infection with microbiological confirmation either by
a. IgM antibody against Nipah virus by ELISA in serum or CSF
b. Nipah virus RNA identified by PCR from respiratory secretions, urine, or cerebrospinal fluid.

Management of patient: There is no definite therapy for Nipah viral disease. Management is supportive. Because of the risk of person-to-person transmission, standard infection control practices and proper barrier nursing techniques should be followed. Ribavirin has been found effective only in vitro and usefulness in clinical practice remains uncertain.

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Hi, I’m Chakra, the man behind GITAB | Knowledge Hub, from Lumbini (Born place of Lord Buddha) Nepal. I am a student of Microbiology. Feel free to say hello via Facebook &Twitter.

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