Nipah Virus and Nipah virus disease described
- 2. INTRODUCTION Nipah virus disease (NVD) is an emerging zoonotic infectious disease caused by Nipah virus (NiV) belonging to the genus Henipavirus of the family Paramyxoviridae. Nipah virus was named after one of the affected Malaysian villages, Sungai Nipah. It mainly affects pigs and humans. Since its discovery in 1999, the outbreaks of NiV have been reported from five countries including India.
- 3. INDIAN SCENARIO In India, initial NiV outbreaks in humans were reported from West Bengal in 2001 and 2007. More recently since 2018, cases have been reported from Kerala as localized outbreaks. Current outbreak has occurred in the Kozhikode district of Kerala. Till date, a total of 6 cases have been reported out of which 6 were confirmed and 2 deaths were reported (1 suspect and 1 confirmed). 3
- 4. Transmission and Reservoir Direct transmission Bat to Human • Exposure to bodily fluids of bat such as blood, saliva, or excrement particularly through contaminated food. • Contaminated date palm tree sap which is traditionally harvested overnight has been identified as Source of direct NiV infection in Bangladesh. Human to Human • Through contact with contaminated tissues or body fluids (reported from India, Bangladesh, and Philippines. Through an intermediate host • Eating contaminated fruits (swine) or grazing on grass infected with bat droppings. 4
- 5. Pathogenesis and Immune response NiV infection is generally accepted to be caused through oral or nasal route in humans after getting exposed to infected food, body fluids, or tissues. Secondary sites of NiV infection are generally found as lesions spread throughout the vasculature, lung, and brain. This indicates that NiV infection spread by hematogenous route followed by inflammation of blood vessels. Vasculitis is generally observed in small arteries, arterioles, and capillaries and may affect organs like brain, lung, heart, and kidney 5
- 6. 6 Incubation period: varies from 6-21 days for acute presentation, however, for 90% of the episodes, the incubation period will be less than 2 weeks. Case Fatality Rate: 40-75% in Laboratory confirmed cases
- 7. Clinical Presentation in Humans Acute Clinical Presentation. Most patients present with fever, headache, vomiting, and myalgia. During illness, symptoms progress to acute encephalitis with drowsiness, dizziness, altered sensorium areflexia, hypertension, and tachycardia. Neurologic sequelae. 20% -30% of the recovered patients may have persistent neurological deficits. Neurological sequalae may include clinical depression, cognitive difficulties, quadriparesis, or nerve palsies. 7
- 8. LABORATORY DIAGNOSIS Samples 1. Swab (Nasal and oropharyngeal) 2. Blood/Serum. 3. Urine sample 4. CSF 5. Tissue sample- brain, kidney, spleen etc As NiV is a highly contagious pathogen with no available treatment, only essential samples should be collected which are required for clinical management, and containment of samples should be ensured. Further, if any biochemistry or pathological test is required to be done, it should be done in completely closed automated systems ensuring the proper containment levels and biowaste disposal. 8
- 9. Lab Diagnosis cont.. Laboratory Diagnosis Protocols • In acute phase, NiV infection can be confirmed by detecting NiV specific RNA in the clinical samples using molecular methods (RT-PCR) • In later phase of illness (10-14 days post the symptom onset), the NiV infection can be detected using serological methods (ELISA) 9
- 10. TREATMENT Currently there is no known treatment or vaccine available for either people or animals. Treatment is limited to intensive supportive care, including rest, hydration, and treatment of symptoms as they occur. Ribavirin, an antiviral may have a role in reducing mortality among patients with encephalitis caused by Nipah virus disease, but its efficacy is unclear. Immunotherapeutic treatments (monoclonal antibody therapies) are currently under development and evaluation for treatment of NiV infections. One such monoclonal antibody, m102.4, has completed phase 1 clinical trials and has been used on a compassionate use basis. Focus should be on preventive measures. 10
- 11. Nipah as a biological weapon Nipah virus if is a zoonotic spillover it is a rare isolated event. However, when person to person transmission is high, virus has a chance to find right combination of mutations to become more transmissible and can be used as deadly weapon. Nipah virus can infect humans and the case- fatality rate may be as high as 75% There is no effective treatment or vaccine for the disease CDC identifies it as a Category C bioterrorism agent. Category C agents are emerging pathogens that could be engineered for mass dissemination in the future because of availability; ease of production and dissemination; potential for high morbidity and mortality rates and major health impact. 11