Medical Virology Assignment.docx

AMITY INSTITUTE OF VIROLOGY AND IMMUNOLOGY

ASSIGNMENT MEDICAL VIROLOGY

TOPIC- EMERGING VIRUSES- NIPAH VIRUS

SUBMITTED TO:

SUBMITTED BY:

DR. BENNET ANGEL

DEEPAK SINGH

AMITY INSTITUTE OF VIROLOGY AND IMMUNOLOGY

M.SC. VIROLOGY Roll NO. A12137418002

Emerging disease is a term used to describe the appearance of a previously unrecognized infection in a particular host species, or a previously known infection that has expanded into a new ecological niche or geographical zone, often accompanied by a significant change in pathogenicity. Some of the factors affecting the emergence and distribution of virus diseases:  

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Involving the virus Mutation and selection New genetic material—zoonosis or recombination/ reassortment Involving transmission Climate and weather Overcrowding Rapid air travel Changes in sexual activities or numbers of partners Intravenous drug use Introduction of new medical interventions War and famine Humans venturing into new environments Vector density and exposure Occupational exposure Involving host resistance Immunosuppression Nutritional state

INTRODUCTION 

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Nipah virus (NiV) is a member of the family Paramyxoviridae, genus Henipavirus. NiV was initially isolated and identified in 1999 during an outbreak of encephalitis and respiratory illness among pig farmers and people with close contact with pigs in Malaysia and Singapore. Its name originated from Sungai Nipah, a village in the Malaysian Peninsula where pig farmers became ill with encephalitis. The new agent, now named Nipah virus after the locality it was first reported, shares 80% sequence homology with Hendra virus, with both viruses now classified as henipaviruses within the Paramyxoviridae family. Nipah virus (NiV) is a zoonotic virus (it is transmitted from animals to humans). Nipah virus infection in humans causes a range of clinical presentations, from asymptomatic infection (subclinical) to acute respiratory infection and fatal encephalitis. Nipah virus can be transmitted to humans from animals (such as bats or pigs), or contaminated foods and can also be transmitted directly from human-to-human. Nipah virus is widely distributed across Northeast India, Bangladesh, and Southeast Asia, with phylogenetic analyses revealing the virus to be diverging within specific geographical localities. Fruit bats of the Pteropodidae family are the natural host of Nipah virus.

GENOME AND ITS STRUCTURE The NiV genome consists of a negative-sense, single-stranded RNA of approximately 18.2 kb, encoding six structural proteins, nucleoprotein (N), phosphoprotein (P), matrix protein (M), fusion protein (F), attachment glycoprotein (G), and the large protein or RNA polymerase protein (L). In addition, the P gene encodes three nonstructural proteins by RNA editing (V and W proteins) or an alternative open reading frame (C protein)

TRANSMISSION 

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NiV transmission from bats to humans is through two main pathways, i.e., intermediate hosts (pigs and horses) and food-borne transmission via date palm sap contaminated with the saliva or urine of fruit bats A retrospective study in Malaysia found that workers show severe influenza-like symptoms after slaughtering NiV-infected swine In the Philippines, people were infected by butchering horses or consuming horsemeat No cases of person-to-person spread have been found in Malaysia or Singapore, but in the Philippines, direct human-to-human virus transmission has been reported

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In India, human-to-human transmission of NiV was discovered in 2001. In a case of NiV infection in a human in 2007, date palm sap contaminated by bats was considered to mediate NiV spillover from bats to humans In Bangladesh, where people consume palm sap, frequent infection by NiV and personto-person NiV transmission has occurred. it was demonstrated that Syrian hamster infection could occur after drinking artificial palm sap mixed with NiV and infrared camera monitoring showed that bats frequently fly around or directly contact palm sap trees to urinate or defecate

OUTBREAKS 1. Nipah virus infection was first recognized in a large outbreak of 265 suspected cases in peninsular Malaysia during September 1998 to April 1999. Most patients had contact with sick pigs or had been in close physical contact with Nipah virus infected patients and then presented primarily with encephalitis. 2. first identification of Nipah virus as a cause of an outbreak of encephalitis was reported in 2001 in Meherpur district of Bangladesh. Since then, outbreaks of Nipah virus encephalitis have been reported almost every year in selected districts of Bangladesh. The Nipah outbreaks have been identified in Naogoan (2003), Rajbari and Faridpur (2004), Tangail (2005), Thakurgaon, Kushtia and Naogaon (2007), Manikgonj and Rajbari (2008), Rangpur and Rajbari (2009), Faridpur, Rajbari and Madaripur (2010) and

Lalmohirhat, Dinajpur, Rangpur and Comilla (2011) and Joypurhat, Rajshahi, Rajbari and Natore (2012). Repeated outbreaks of Nipah virus encephalitis were established in some districts. Sporadic cases of Nipah virus encephalitis have been reported, mostly from the west and north-western regions of Bangladesh almost every year, with high mortality and constituting a public health threat. Up to March 31, 2012 a total of 209 human cases of NiV infection in Bangladesh were reported; 161 (77%) of them died. 3. India reported three outbreaks of Nipah virus encephalitis in the eastern state of West Bengal, bordering Bangladesh, in 2001 and 2007. Seventy one cases with 50 deaths (70% of the cases) were reported in two outbreaks. During January and February 2001, an outbreak of febrile illness with neurological symptoms was observed in Siliguri, West Bengal. Clinical material obtained during the Siliguri outbreak was retrospectively analyzed for evidence of NiV infection. 4. On 19 May 2018, a Nipah virus disease (NiV) outbreak was reported from Kozhikode district of Kerala, India. This is the first NiV outbreak in South India. There have been 17 deaths and 18 confirmed cases as of 1 June 2018. The two affected districts are Kozhikode and Mallapuram. A multi-disciplinary team led by the Indian Government’s National Centre for Disease Control (NCDC) is in Kerala in response to the outbreak.

SIGNS AND SYMPTOMS 

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Nipah Virus is usually associated with inflammation of the brain due to which severe days of fever can often lead to a state of confusion, disorientation a nd even persistent drowsiness. If not taken care of, these symptoms can even cause a coma in a span of 24-48 hours. There are many patients who show neurological, respiratory and pulmonary signs as well. Some common signs and symptoms of NiV are headache, fever, nausea, dizziness, drowsiness and mental issues such as confusion. These symptoms can last up to 7 10 days. The symptoms may take from four to 14 days to appear after a person gets infected. The early symptoms are not very clear and can easily be confused with that of viral fever and common cold. The virus can kill between 40 per cent to 100 per cent of those infected by it.

DIAGNOSIS Laboratory diagnosis of a patient with a clinical history of NiV can be made during the acute and convalescent phases of the disease by using a combination of tests. Virus isolation attempts and real time polymerase chain reaction (RT-PCR) from throat and nasal swabs, cerebrospinal fluid, urine, and blood should be performed in the early stages of disease. Antibody detection by ELISA (IgG and IgM) can be used later on. In fatal cases, immunohistochemistry on tissues collected during autopsy may be the only way to confirm a diagnosis.