NIPAH Virus Source,Transmission,Signs & Symptoms,Diagnosis,Treatment,Prevention. - презентация

1 NIPAH Virus Source,Transmission,Signs & Symptoms,Diagnosis,Treatment,Prevention

2 Introduction Nipah virus (NiV) is an emerging zoonotic virus (a virus transmitted to humans from animals). In infected people, Nipah virus causes severe illness characterized by inflammation of the brain (encephalitis) or respiratory diseases. It can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers. Nipah virus (NiV) is an emerging zoonotic virus (a virus transmitted to humans from animals). In infected people, Nipah virus causes severe illness characterized by inflammation of the brain (encephalitis) or respiratory diseases. It can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers. Nipah virus is closely related to Hendra virus. Both are members of the genus Henipavirus, a new class of virus in the Paramyxoviridae family. Nipah virus is closely related to Hendra virus. Both are members of the genus Henipavirus, a new class of virus in the Paramyxoviridae family. Although Nipah virus has caused only a few outbreaks, it infects a wide range of animals and causes severe disease and death in people, making it a public health concern. Although Nipah virus has caused only a few outbreaks, it infects a wide range of animals and causes severe disease and death in people, making it a public health concern.

3 Transmission During the initial outbreaks in Malaysia and Singapore, most human infections resulted from direct contact with sick pigs or their contaminated tissues. Transmission is thought to have occurred via respiratory droplets, contact with throat or nasal secretions from the pigs, or contact with the tissue of a sick animal. During the initial outbreaks in Malaysia and Singapore, most human infections resulted from direct contact with sick pigs or their contaminated tissues. Transmission is thought to have occurred via respiratory droplets, contact with throat or nasal secretions from the pigs, or contact with the tissue of a sick animal. In the Bangladesh and India outbreaks, consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection. In the Bangladesh and India outbreaks, consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection. During the later outbreaks in Bangladesh and India, Nipah virus spread directly from human-to-human through close contact with people's secretions and excretions. In Siliguri, India, transmission of the virus was also reported within a health-care setting, where 75% of cases occurred among hospital staff or visitors. From 2001 to 2008, around half of reported cases in Bangladesh were due to human-to-human transmission. During the later outbreaks in Bangladesh and India, Nipah virus spread directly from human-to-human through close contact with people's secretions and excretions. In Siliguri, India, transmission of the virus was also reported within a health-care setting, where 75% of cases occurred among hospital staff or visitors. From 2001 to 2008, around half of reported cases in Bangladesh were due to human-to-human transmission.

4 How affects cells To infect a cell, viruses must bind to a viral-specific receptor on the cells surface in order to penetrate it. Lees team identified a cell receptor called Ephrin-B2 as the key used by the Nipah virus to unlock the cells. Located on brain cells and cells lining the blood vessels, Ephrin-B2 is critical to nervous system development and the growth of blood vessels in human and animal embryos. Ephrin-B2 is found in humans, horses, pigs and bats, which may explain why the infection can jump so easily from one species to another. To infect a cell, viruses must bind to a viral-specific receptor on the cells surface in order to penetrate it. Lees team identified a cell receptor called Ephrin-B2 as the key used by the Nipah virus to unlock the cells. Located on brain cells and cells lining the blood vessels, Ephrin-B2 is critical to nervous system development and the growth of blood vessels in human and animal embryos. Ephrin-B2 is found in humans, horses, pigs and bats, which may explain why the infection can jump so easily from one species to another.

5 Clinical Features in Human Fever Migraine Vomiting Emphysema Myalgia Encephalitis (may relapse after recovery) Meningitis Disorientation Neurologic deficits (may persist after recovery) Coma Death Fever Migraine Vomiting Emphysema Myalgia Encephalitis (may relapse after recovery) Meningitis Disorientation Neurologic deficits (may persist after recovery) Coma Death

6 Diagnosis Nipah virus infection can be diagnosed by a number of different tests: Nipah virus infection can be diagnosed by a number of different tests: serum neutralization serum neutralization enzyme-linked immunosorbent assay (ELISA) enzyme-linked immunosorbent assay (ELISA) polymerase chain reaction (PCR) assay polymerase chain reaction (PCR) assay immunofluorescence assay immunofluorescence assay virus isolation by cell culture. virus isolation by cell culture.

7 Treatment Adding to the mortality rate for Nipah virus infection is that there is no known cure for it. Some infected individuals who received the antiviral drug ribavirin early in their illness had less severe symptoms. Treatment is mostly focused on managing fever and the neurological symptoms. Severely ill individuals will be hospitalized and may require the use of a respirator (ventilator). Adding to the mortality rate for Nipah virus infection is that there is no known cure for it. Some infected individuals who received the antiviral drug ribavirin early in their illness had less severe symptoms. Treatment is mostly focused on managing fever and the neurological symptoms. Severely ill individuals will be hospitalized and may require the use of a respirator (ventilator).

8 Prevention and Control Control Strategies Following Nipah Outbreak Control Strategies Following Nipah Outbreak Upon the discovery of Nipah, Malaysia and Singapore developed national plans to help eradicate the disease (see References: Nor 1999): Upon the discovery of Nipah, Malaysia and Singapore developed national plans to help eradicate the disease (see References: Nor 1999):References Phase I: Immediate eradication by mass culling of pigs (this resulted in the loss of over 1 million swine and had a significant impact on the pig industry in Malaysia) Phase I: Immediate eradication by mass culling of pigs (this resulted in the loss of over 1 million swine and had a significant impact on the pig industry in Malaysia) Phase II: Antibody surveillance of high-risk farms to prevent future epidemics Phase II: Antibody surveillance of high-risk farms to prevent future epidemics Future actions: Further research into natural hosts, pathogenesis, and epidemiology Future actions: Further research into natural hosts, pathogenesis, and epidemiology Other preventive actions included the following: Other preventive actions included the following: A ban on transporting pigs within the country A ban on transporting pigs within the country A total ban on porcine production (which has since been lifted) A total ban on porcine production (which has since been lifted) Education about contact with pigs Education about contact with pigs Use of personal protective equipment among persons exposed to pigs Use of personal protective equipment among persons exposed to pigs

9 US Policies Since the Malaysian Outbreak The United States did not import live pigs from Malaysia or Singapore during the 1999 Nipah epidemic, and imports of live pigs from that region have remained minimal. Although pork by-products (such as soups, broths, leathers, and animal feed products) were shipped to the United States, there has been no evidence of spread of the virus within the United States. Travel logs from the affected region to the Unites States were cross- referenced and investigated (several travelers were carrying pork products intended for human consumption). Also, animal imports known to be destined for US zoos and wildlife parks were inspected. Again, no evidence of infection was found. The US Department of Agriculture has continued to encourage pork producers, associated veterinary personnel, and the medical community to remain aware of dangerous foreign animal diseases (including Nipah virus infection) that have the potential to contaminate United States livestock populations. Source: APHIS Center for Emerging Issues

10 Other Considerations for Prevention and Control 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 (see References: Enserink 2000). 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 (see References: Enserink 2000).References Import/export caution and biosecurity planning should increase. Import/export caution and biosecurity planning should increase. Increased hygiene and updated protocols on pig operations are necessary. Increased hygiene and updated protocols on pig operations are necessary. Nipah virus, like the related Hendra virus, is classified as a biosecurity level 4 (BSL-4) agent. Nipah virus, like the related Hendra virus, is classified as a biosecurity level 4 (BSL-4) agent. Caution should be taken among heathcare professionals, research investigators, veterinary personnel, and individuals in close contact with pig production. Although the risk of transmission is considered low, precautionary measures are appropriate considering the limited epidemiologic knowledge to date. Caution should be taken among heathcare professionals, research investigators, veterinary personnel, and individuals in close contact with pig production. Although the risk of transmission is considered low, precautionary measures are appropriate considering the limited epidemiologic knowledge to date.

11 Public Health Issues During the Malaysian outbreak, over 250 cases and 100 deaths occurred, indicating that the virus poses a substantial threat to exposed humans. Observations to date include the following: During the Malaysian outbreak, over 250 cases and 100 deaths occurred, indicating that the virus poses a substantial threat to exposed humans. Observations to date include the following: Overwhelming epidemiologic evidence suggests that human exposure is caused by direct contact with pigs, probably with infected secretions and discharges. Overwhelming epidemiologic evidence suggests that human exposure is caused by direct contact with pigs, probably with infected secretions and discharges. Reports suggest that between 86% and 93% of human Nipah virus cases have involved occupational exposure to pigs (see References: CDC 1999, University of Wisconsin). Reports suggest that between 86% and 93% of human Nipah virus cases have involved occupational exposure to pigs (see References: CDC 1999, University of Wisconsin).References Exposure via contact with other animals has not been ruled out. Exposure via contact with other animals has not been ruled out. The virus is not easily transmitted to humans. The virus is not easily transmitted to humans. No serologic evidence exists for transmission directly from fruit bats. No serologic evidence exists for transmission directly from fruit bats. 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 patients (see References: Mounts 2001). In the current outbreak in Bangladesh, news sources report that epidemiologists suspect that person-to-person transmission may be occurring, but nothing definite has been determined as yet. 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 patients (see References: Mounts 2001). In the current outbreak in Bangladesh, news sources report that epidemiologists suspect that person-to-person transmission may be occurring, but nothing definite has been determined as yet.References

12 Source of Information a/ htm a/ htm a/ htm a/ htm 2/en/ 2/en/ 2/en/ 2/en/ ecurity/ag-biosec/anim-disease/nipah.html ecurity/ag-biosec/anim-disease/nipah.html ecurity/ag-biosec/anim-disease/nipah.html ecurity/ag-biosec/anim-disease/nipah.html report.com/html/reports/life_sciences/report html report.com/html/reports/life_sciences/report html