PATHOGENESIS OF NIPAH VIRUS INFECTION[11]:

	Primary Virus Replication
	↓
	Viremia
	↓
	Vesicular (Endothelial / Smooth muscle) infection
	↓
↓	Vasculistis	↓
Thrombosis and obstruction		Extra vascular spread of virus

Ischemia and Infraction		Parenchymal infection and cellular injuries

Fig 1: Pathogenesis of Nipah virus^[11]

TRANSMISSION: RISK FACTORS - PRECAUTIONARY MEASURES^[9-15]:

Chances of transmission (Fig 2), risk factors and its precautionary measures

Fig 2: Transmission of Nipah virus^[9]

1. From Bat to human:

Some bats carry Nipah virus and contaminate raw sap, taking raw date palm sap should be avoided which infect the human with virus. Better to consume boiled sap or molasses.

2. Human to Human:

· After coming in contact with infected patient better to wash hands with anti aseptic liquids and to sleep in separate bed.

· Maintain >1 full-stretched arm distance (1 meter or 3 feet) from patient.

· Patients belonging should keep separately and the items utilized by patient should wash soap and water.

2.1. Patient to health care workers

· Patients suffering with NiV symptoms should be kept under isolated and good ventilated premises.

· Use mask and gloves during history- taking, physical examination, sample collection and other care-giving to suspected Nipah cases Avoid unnecessary contact with suspected Nipah cases

· Standard precautionary measures should be followed for preventing infection at hospital.

2.2. Patient to other care givers/ close contact

· During history- taking, physical examination, wear surgical mask, surgical gloves (examine, specimen collection) and gown.

· During specimen collection and other invasive procedures (such as nasopharyngeal suction, endotracheal intubation) wear N95 mask, surgical gloves and gown.

· Wash hands in with soap and water at least for 20 seconds, or clean hand using 1-2 ml alcohol based hand sanitizer (chlorhexidine or 70% alcohol hand sanitizers) after providing any care to patient.

· Use disposable items while providing NG tube, oxygen mask, and endotracheal tube.

SYMPTOMS^[9-13]:

Without showing any symptoms NiV infections can progress silently in humans. However, people infected with this virus usually display influenza-like symptoms.

Once a person is infected with Nipah virus, it usually takes five to 14 days for the symptoms of an infection to appear gradual progression to coma within 24 to 48 hours.

Nipah virus is classified internationally as a biosecurity level (BSL) 4 agent. NiV has a number of important attributes that makes it a potential to be agents of bioterrorism. The symptoms of Nipah virus infection include:

· Fever within 3-14 days after contacting the virus

· Alveolar hemorrhage, pulmonary edema and aspiration pneumonia were often encountered in the lungs. These may lead to pneumonia and acute respiratory distress syndrome (ARDS)

· Dizziness

· Drowsiness

· Mayalgia (Muscle pain

· Headache

· A sore throat

· Nausea

· Vomiting

· Mental confusion and disorientation

· Atypical pneumonia

· Brain swelling or fatal encephalitis

SURVEILLANCE [13 - 15]:

Table 1: Morbidity and mortality due to Nipah and other virus

Month/year	Location	No. of cases	No. of Deaths	Case Fatality Rate
1998-1999	Malasia, Singapore	276	106	36%
Feb 2001	Silliguri**	66	45	68%
April, May 2001	Meherpur*	13	8	69%
Jan 2003	Naogaon*	12	8	67%
Jan 2004	Rajbari*	31	23	74%
April 2004	Faridpur*	36	27	75%
Jan-Mar 2005	Tangail*	12	11	92%
Jan-Feb 2007	Thakurgaon*	7	3	43%
Mar 2007	Kushtia*	8	5	63%
Apr 2007	Nadia**	5	5	100%
Apr 2007	Pabna, Natore & Naogaon*	3	1	33%
Feb 2008	Manikgonj*	4	4	100
Apr 2008	Rajbari	7	5	71%
Jan 2009	Gaibandha, Rangour, Niphamari* Rajbari*	3 1	0 1	0% 100%
Feb-Mar 2010	Faridpur* Faridpur, Rajbari, Gopalgonj* Kurigram*	8 8 1	7 7 1	87.5% 87.5% 100%
Jan-Feb 2011	Thakurgaon*	44	40	91%
Jan 2012	Joypurhat*	12	10	83%
Jan-Apr 2013	Pabma, Natore, Naogojn, Gaibardha, Manikganj*	24	21	88%
Jan-Feb 2014	13 districts*	18	9	50%
Jan-Feb 2015	Niphamani, Ponchaghor, Paridpur, Magura, Naugaon, Rajbari*	9	6	67%
May-June 2018	Kozhikode, Malappuram**	35	17	48.5%

** India, *Bangladesh

DIAGNOSIS [14-15] :

Table 2: Overview of diagnostic tests developed in various laboratories

TECHNIQUE	LABBORATOTY DEVELOPED COUNTRY	ASSAY METHOD
ELISA (detection of viral antigen)	CDC, USA Nat. Inst. Inf. Dis., Japan CDC, USA	· Antigen-capture ELISA using antibodies produced by DNA immunization · Antigen-capture ELISA using antibodies produced by DNA immunization · Monoclonal antibody-based antigen-capture ELISA
ELISA (detection of IgM and IgG)	DVS, Malaysia Chinese Nat. Diagn. Center for Exotic Animal Dis. Institute Trop. Med., Japan Institute Trop. Med., Japan	· Solid-phase blocking ELISA · Indirect ELISA based on E coli-expressed N · Indirect IgG ELISA based on recombinant N · IgM capture ELISA based on recomb. N
Luminex	CDC, USA CSIRO, Australia	Binding assay Receptor inhibition (blocking) assay
Neutralization	CSIRO, Australia	Plaque assay
Pseudo type neutralization	CDC, USA Nat. Inst. Inf. Dis., Japan Nat. Inst. Inf. Dis., Japan	VSV pseudo types expressing NiV F /G VSV pseudo types expressing NiV F /G VSV expressing secreted alkaline phosphatase pseudo typed with NiV F/G
Immuno histochemistry	Nat. Inst. of Animal Health, Japan	Monoclonal antibody-based Immuno histochemistry
PCR	Institute Pasteur, France Inst. of Zoology, UK Inst. of Zoology, UK Chulalongkorn Uni. Hosp., Thailand CDC, USA	Real-time RT-PCR (Taqman) using primers in N gene Real-time RT-PCR (Taqman) using primers in P gene SYBR Green assay using primers in N gene Duplex nested RT-PCR (bat urine specimen) Taqman array card (multiplex)
Virus culture	CSIRO, Australia	Plaque assay

NiV diagnosed with combination of different tests using

· Throat and nasal swabs which are sent to the laboratory for testing.

· Blood test.

· Virus isolation and detection.

· Cerebrospinal Fluid analysis.

· Urine test.

PREVENTION, CONTROL AND TREATMENT^[12,
16-19]:

Supportive/General Management:

1. Isolation (preferably in a separate unit)

2. Barrier nursing e.g. personal protection using masks, gloves, gowns, shoe covers

3. Hand washing with soap & water before and after handling/visiting patients

4. Resuscitation (if needed): ABC [Airway Breathing Circulation]

5. Unconscious patient posture change, care of eye, bladder, bowel and mouth

6. Oxygen inhalation if there is respiratory difficulty.

7. Nutritional support: oral/NG tube feeding according to the condition of the patient

8. Maintain fluid and electrolyte balance (Adults: 5% DNS, Children: 5% DNS, half or quarter strength saline)

9. Fluid restriction: 30% restriction particularly in children. 2/3 of the daily maintenance can be given in children if the child is not in shock

10. Maintain intake output chart

11. Bronchodilators may be given through large spacers

Symptomatic Treatment:

1. Treatment of fever: Paracetamol -15mg/kg/dose or 500 mg for adult if temperature ≥101.3oF (≥38.5°C). (Not more than 4 times in 24 hours)

2. Treatment of convulsion:

a. If patient present with convulsion:

Adult: IV Diazepam 10mg stat

Children: per rectal diazepam: 0.5mg/ kg (maximum 10mg) as stat dose It can be repeated once again after 10 min

b. If seizure persists despite above measures, treat as status epilepticus

c. If presents with history of convulsion(s): Give maintenance treatment with Phenobarbiton (Adult: 60 mg BD; Children: 5 mg/ kg/ day BD)

3. Treatment of raised intracranial pressure (i.e., bradycardia, hypertension, papilloedema and deterioration of consciousness)

a. Elevation of head to 30⁰ with straight head

b. Mannitol

i Adult: 200ml IV running stat and 8 hourly until features of raised ICP resolved or not beyond eight doses of Mannitol.

ii Children: 2.5 – 5 ml/kg over 20 minutes as bolus dose stat and 6 hourly, not beyond eight doses of mannitol

4. Treatment of hypoglycemia (<40 mg/dl or <2.2 mmol/L)

i Adult: 25% glucose-40 ml IV

ii Children: 10% glucose 5 ml/kg bolus and can be repeated if necessary

5. Treatment of Shock:

i. 0.9% Normal Saline

a. Adult: 1 liter in 1st hour

b. Children: 20ml/kg over 20 mins

ii. Dopamine (when needed):

a. Adult: 05-20 microgram/kg/min

b. Children: 5-10 microgram/ kg/ min

Other treatment:

The following may be given if indicated.

1. Antibiotic e.g. IV Ceftriaxon (Children: 100mg/ kg once daily, Adult: 2gm BD for 10 days in suspected case of bacterial meningitis

2. IV Acyclovir 10mg/ kg 8 hourly as infusion over 20 min for 10 days

3. Broad spectrum antibiotics + Metronidazole/Clindamycin (for aspiration pneumonia/secondary bacterial infection)

Criteria for transferring patient to ICU:

1. Signs of impending respiratory failure

a. Respiratory rate:

Adult: > 30/min

Children: ≥ 70/min

b. Oxygen saturation <90%

c. Central cyanosis

2. Uncontrolled seizures

3. GCS ≤8

4. Hemodynamic instability (i.e., bradycardia, hypotension and capillary refilling time > 3 Seconds.

5. Multi organ failure

Criteria for referral to higher centre

· Deteriorating level of consciousness

· Uncontrolled convulsion

· Worsening respiratory distress

· Uncontrolled haemodynamic instability

Care during transportation of the patient

1) Maintaining patent airway

a. lateral position

b. airway suction if required

2) Oxygenation

3) Monitoring during transport

4) Personal protection for the person related to transport

Requirements for an isolation room:

· Standard should be equivalent to High Dependency Unit (HDU)

· Exhaust fan should be switched on

· Separate Pulse oxymeter, Non invasive BP, stethoscope, BP machine, Thermometer, Torch light

· Supply of adequate

§ disposable gloves,

§ gown (either disposable/autoclavable),

§ surgical mask/N95 mask,

§ hand washing facilities,

§ chlorhexidine hand washing solution/ alcohol 60%

· One Mechanical Ventilator for each four bedded HDU

§ HME filter

§ close circuit suction apparatus

Monitoring and follow up of surviving Nipah cases (two weeks from discharge):

1. Higher psychic functions – intact/ impaired

2. Orientation (time, place and person) fully oriented/impaired

3. Speech– intact/ impaired

4. Swallowing-– intact/ impaired

5. Seizures- controlled/uncontrolled

6. Motor activities- upper limbs- power, coordination

7. Lower limbs- power, coordination, gait

8. Daily activities (feeding, dressing, washing, bathing) - fully independent, partially dependent, fully dependent

Treatment is limited to supportive care. Because Nipah virus encephalitis can be transmitted person-to-person, standard infection control practices and proper barrier nursing techniques are important in preventing hospital-acquired infections (nosocomial transmission) [19].

The drug Ribavirin has been shown to be effective against the viruses in vitro, but human investigations to date have been inconclusive and the clinical usefulness of Ribavirin remains uncertain [19].

Passive immunization using a human monoclonal antibody targeting the Nipah G glycoprotein has been evaluated in the post-exposure therapy in the ferret model and found to be of benefit [19].

VACCINES [12, 20]:

Table 3. Nipah vaccine candidates with preclinical data

DEVELOPER	CANDIDATE NAME/ IDENTIFIER AND INSTITUTION	EFFICACY OR IMMUNOGENICITY DATA IN ANIMAL MODEL	REFERENCE
CFIA-NCFAD	ALVAC-F/G*	100% protection in pig model, no evidence of clinical illness, following 2 vaccinations (14 days apart) starting 28 days before challenge	21
CDC	VSV-NiV M F or G	100% protection in hamster model, no evidence of clinical illness, following single vaccination 32 days before challenge	22
CAAS-SKLVB	rLa-NiV G and/or rLa-NiVF**	High neutralizing antibody titers induced in pigs following 2 vaccinations (4 weeks apart)	23
INSERM	VV-NiV.F and/or G	100% protection in hamster model, following 2 vaccinations (1 month apart) starting 4 months before challenge	24
INSERM	AAV-NiVM G	100% protection in hamster model, no evidence of clinical illness, following single vaccination 32 days before challenge	25
RML	rVSV-EBOV-GP-NiV-G	100% protection in hamster model following single-dose vaccination 1 day before challenge 100% protection in AGM model following single-dose vaccination, 29 day before challenge	26 27
UTMB	VSV-NiVB F and/or G	100% protection in ferret model, no evidence of clinical illness, following single vaccination 28 days before challenge	28
UoT	rMV-Ed-G	100% protection in hamster model, no evidence of clinical illness, following 2 vaccinations (21 days apart) starting 28 days before challenge 100% protection in AGM model, but no protection against infection (pathological changes observed in brain), following 2 vaccinations (28 days apart) starting 35 days before challenge	29
USU	V-NiVG (VEE)	High neutralizing antibody titers induced in mice following 3 vaccinations at weeks 0, 5 and 18	30
Zoetis, Inc. /USU	HeVsG (subunit) + CpG	100% protection in ferret model, no evidence of clinical illness, following 2 vaccinations (20 days apart) 20 or 434 days before challenge	31

All R&D activities for NiV vaccines are in the pre-clinical stage. Many vaccine candidates including different live recombinant vaccine and subunit vaccines have been produced and tested in various animal models including hamsters, pigs, cats, ferrets and AGMs. These vaccines are based on the F and/or G glycoproteins, and essentially target the induction of NiV neutralizing antibodies, as done with other human Paramyxovirus vaccines such as mumps or measles vaccines.

CONCLUSION:

Nipah virus (NiV) infection is an emerging Zoonosis that causes severe disease in both animals and humans. In present situation NiV infected human or animals can get care and control measures are followed. As per WHO no particular vaccine has been launched in market and still the vaccines are under the preclinical study. Control measures have been followed to prevent the human to human and animal to human transmission with continuous medication and by following management studies. Personal protective management studies and Health Education is strongly recommended to overcome the NiV outbreak.

REFERENCES:

1. http://www.who.int/csr/disease/nipah/en/

2. Prof A K M Saiful Islam, Addl Director General (Admn), DGHS

3. Dr Md Mumtazudin Bhuiyan, Director, Hospital & Clinic, DGHS

4. Prof Shahina Tabassum, Head, Dept of Virology, BSMMU, Dhaka

5. Prof Syeda Afroza, Head, Dept of Pediatrics, Sir Salimullah Medical College, Dhaka.

6. Anna R. Thorner, Raphael Dolin, in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases (Eighth Edition), Zoonotic Paramyxovirus, 2015.

7. Tom Solomon, in Manson's Tropical Infectious Diseases (Twenty-third Edition), Virus Infections of the Nervous System Epidemiology, 2014.

8. Sharon Lewin, in Principles of Gender-Specific Medicine (Second Edition), Gender Differences in Emerging Infectious Diseases, Nipah Virus, 2010.

9. https://www.practo.com/health-wiki/nipah-virus-symptoms- treatment-transmission /172/ article.

10. World Health Organization (WHO). Nipah Virus (NiV) Infection

11. Kum Thong Wong et. Al. Nipah virus pathology working group: American journal of pathology Vol 161. No. 6, December 2002.

12. National Guideline for Management, Prevention and Control of Nipah Virus Infection including Encephalitis Directorate General of Health Services Ministry of Health & Family Welfare Government of the People’s Republic of Bangladesh Technical support: World Health Organization, Bangladesh Country Office. 1^st Edition, December 2011.

13. 4morbidity-and-mortality-nipah-sear-2001-2018.

14. Kulkarni DD, Tosh C, Venkatesh G, Senthil Kumar D. Nipah virus infection: current scenario. Indian J Virol. 2013 Dec; 24(3):398-408.

15. WHO South East Asia surveillance and outbreaks May-June 2018.

16. Nipah national guideline for management prevention and control of Nipah. Hossain, M.J., et al. Clinical presentation of Nipah virus infection in Bangladesh. Clin Infect Dis, 2008. 46(7): p. 977-84.

17. Chong HT, H.M., Tan CT. Difference in epidemiologic and clinical features of Nipah virus encephalitis between Malaysian and Bangladesh outbreaks. Neurology Asia, 2008. 13: p. 23-26.

18. Extended Disability Scoring system. WHO Bulletin. 88[8]: 2010. 561-640; WHODAS 2.0

19. UTMC Emergency medicine residents Global and disaster medicine site. CDC ON NIV (NIPAH VIRUS) May 25th, 2018

20. Satterfield BA, Cross RW, Fenton KA, et al. The Immuno modulating V and W proteins of Nipah virus determine disease course. Nat Commun. 2015 Jun 24; 6:7483.

21. Weingartl HM, Berhane Y, Caswell JL, et al. Recombinant Nipah virus vaccines protect pigs against challenge. J Virol. 2006 Aug; 80(16):7929-38.

22. Lo MK, Bird BH, Chattopadhyay A, et al. Single-dose replication-defective VSV-based Nipah virus vaccines provide protection from lethal challenge in Syrian hamsters. Antiviral Res. 2014 Jan; 101:26-9.

23. Kong D, Wen Z, Su H, et al. Newcastle disease virus-vectored Nipah encephalitis vaccines induce B and T cell responses in mice and long-lasting neutralizing antibodies in pigs. Virology. 2012 Oct 25; 432(2):327-35.

24. Guillaume V, Contamin H, Loth P, et al. Nipah virus: vaccination and passive protection studies in a hamster model. J Virol. 2004 Jan; 78 (2):834-40.

25. Ploquin A, Szécsi J, Mathieu C, Guillaume V, Barateau V, Ong KC, Wong KT, Cosset FL, Horvat B, Salvetti A. Protection against Henipavirus infection by use of recombinant adeno-associated virus-vector vaccines. J Infect Dis. 2013 Feb 1; 207(3):469-78.

26. DeBuysscher BL, Scott D, Marzi A, et al. Single-dose live-attenuated Nipah virus vaccines confer complete protection by eliciting antibodies directed against surface glycoprotein. Vaccine. 2014 May 7; 32(22):2637-44.

27. Prescott J, DeBuysscher BL, Feldmann F, et al. Single-dose live-attenuated vesicular stomatitis virus-based vaccine protects African green monkeys from Nipah virus disease. Vaccine. 2015 Jun 4; 33(24):2823-9.

28. Mire CE, Versteeg KM, Cross RW, et al. Single injection recombinant vesicular stomatitis virus vaccines protect ferrets against lethal Nipah virus disease. Virol J. 2013 Dec 13; 10:353.

29. Yoneda M, Georges-Courbot MC, Ikeda F, et al. Recombinant measles virus vaccine expressing the Nipah virus glycoprotein protects against lethal Nipah virus challenge. PLoS One. 2013; 8(3):e58414.

30. Defang GN, Khetawat D, Broder CC, Quinnan GV Jr. Induction of neutralizing antibodies to Hendra and Nipah glycoproteins using a Venezuelan equine encephalitis virus in vivo expression system. Vaccine. 2010 Dec 16;29(2):212-20

31. Pallister JA, Klein R, Arkinstall R, et al. Vaccination of ferrets with a recombinant G glycoprotein subunit vaccine provides protection against Nipah virus disease for over 12 months. Virol J. 2013 Jul 16; 10:237.

Received on 31.08.2018 Accepted on 12.10.2018

Asian J. Pharm. Res. 2018; 8(4): 249-254.

DOI: 10.5958/2231-5691.2018.00043.6