Daffodil International University
General Category => Common Forum => Topic started by: Nahian Fyrose on May 29, 2013, 05:16:22 PM
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Nipah virus Infection
Nipah Virus Infection (NiV) is an emerging infectious disease of public health importance in the South-East Asia Region (Bangladesh).
History
Nipah Virus was first identified during an outbreak of disease that took place in Kampung Sungai Nipah, Malaysia in 1998. The cause of the outbreak in Malaysia was found to be a previously unknown virus, named Nipah after the area where it was identified. Nipah virus is part of the family of viruses called Paramyxoviridae, but researchers have found enough unique characteristics of Nipah.
Outbreaks in Bangladesh
The World Health Organization has confirmed two recent human outbreaks of the deadly Nipah virus have occurred in Bangladesh. WHO said that in February 2004, an outbreak of Nipah virus spread across six Bangladesh districts and caused 17 human deaths in 23 cases a mortality rate of 74%. A second outbreak in the Faridpur district earlier this month killed 18 of 30 cases a 60% mortality rate. Recently February 4 two people died in Lalmonirhat and Dinajpur. (Source: WHO Nipah Virus fact sheet)
Hosts
Nipah virus has been shown to cause clinical disease in swine and humans as well as serologic changes in several common farm animals and in various bat species.
Natural reservoir: The virus's natural reservoir includes three species of Pteropid fruit bat (also referred to as flying foxes). Many Malaysian piggeries have nectar-bearing fruit trees on their property, which would offer the opportunity for introduction of the virus into their swine herds.
Affected hosts: Pigs, humans, and possibly one dog have been reported with clinical illness caused by Nipah virus.
Transmission
Overwhelming epidemiologic evidence suggest that human exposure is caused by direct contact with pigs, probably infected secretion and discharges.
Reports suggest that between 86%and 93% of human Nipah virus cases have involved occupational exposure to pigs.
Exposure via contact with other animals has not been ruled out.
The virus is not easily transmitted to human.
No serologic evidence exits for transmission directly from fruit bats.
Nipah virus can be transmitted to human from animals, and can also be transmitted directly from human to human; in Bangladesh, half of reported cases between 2001 and 2008 were due to human to human transmission.
Clinical Features of Nipah Virus
Fever,
Migraine,
Vomiting,
Drowsiness,
Abdominal pain,
Nausea,
Headache
Weakness,
Encephalitis ,
Meningitis,
Disorientation,
Neurological defects,
Emphysema
Myalgia ( Muscular pain)0
Problems with swallowing and blurred vision
Coma
Death
Diagnosis:
No standard protocol exists for detecting Nipah virus at this time. However, several methods have been used to confirm viral infection.
• History/clinical signs
• Virus isolation (kidney, liver, cerebrospinal fluid)
• IgG-,IgM-capture enzyme linked immunosorbent assay (ELISA)
• Virus neutralization
• Immunohistochemistry (lung, kidney, spleen, heart)
• Reverse transcriptase polymerase chain reaction
Treatment
According to WHO effective treatment has not been developed for Nipah infection. Ribavirin, an antiviral drug, may reduce mortality among patients with encephalitis caused by Nipah virus, although further study is needed .Intensive supportive care is required for infected humans.
Scientists (Vienna, Austria) have made a discovery about the basic biology of Nipah virus, which suggest that cheap existing drugs for high blood pressure and malaria may help fight the disease.
The virus enters the cell through macropinocytosis, and ingestion process in which the cell membrane folds inward, engulfing the virus and it’s receptors in an intracellular vesicle.
Amiloride, which is used to treat hypertension and is known to block macropinocytosis.
Antimalarial chloroquine and hydroxychloroquine raise the pH in intracellular compartment; including the vesicles created by macropinocytosis.In cell culture they found all three drugs block the viral replication efficiently.
Prevention and Control
There is no vaccine against Nipah virus. Routine cleaning and disinfection of pigs farms(with sodium hypochlorite or other detergents) is expected to be effective in preventing infection.
1. Since the original source of transmission is various species of fruit bats, it may be possible to reduce the transmission of Nipah to pigs by removing the fruit source on a farm.
2. Import/export caution and biosecurity planning should increase.
3. Increased hygiene and updated protocols on pig operations.
4. Caution should be taken among healthcare professionals, research investigators, veterinary personnel, and individuals.
5. No human-to-human transmission has been documented. However, because the virus has been found in respiratory secretions and urine of infected patients, standard and droplet infection control precautions should be maintained for infected hospitalized.
Although Nipah virus caused a few of outbreaks, it infects a wide range of animals and causes severe disease and death in people, making it a public health concern.
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Informative post