India: More Suspect Nipah Cases Hospitalized - Initial Tests on 6 Come Back Negative

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With the dual caveats that the incubation period for Nipah is believed to run from 4 days to more than 2 weeks, and that laboratory tests aren't always sensitive enough to detect the virus - particularly early in an infection - the very good news this morning is that the first 6 suspected cases (mostly HCWs) who had direct contact with India's confirmed case, have tested negative. 

This report from IANS.

Six test negative for Nipah in Kerala

IANS | Kochi Last Updated at June 6, 2019 12:20 IST

Samples of six patients suffering from fever were tested negative for Nipah virus, Kerala Health Minister K.K. Shailaja announced on Thursday. She said there was no need to panic as the situation was under control.

(SNIP)

"All these patients are under close observation and continue to be in the isolation ward of a hospital. The youth who tested positive is also recovering well," said Shailaja.

        (Continue . . . )


Ideally, you want to see two negative results 48 hours apart before ruling out infection.  But as we've seen with MERS-CoV (see AJIC: Intermittent Positive Testing For MERS-CoV), negative tests must be evaluated cautiously.

Test results on at least 3 other recently hospitalized cases are pending, as the number suspect cases continues to rise. (see 2 people suspected of having contracted Nipah virus infection hospitalised).

For those seeking a more in-depth look at Nipah diagnostics, the BMJ recently published a detailed open-access overview (see Mazzola LT, Kelly-Cirino C Diagnostics for Nipah virus: a zoonotic pathogen endemic to Southeast Asia BMJ Global Health 2019;4:e001118.).

Summary box

• Current diagnostics for Nipah virus (NiV), a WHO priority pathogen endemic to Southeast Asia, include in-house laboratory-based serological and nucleic acid amplification techniques.
• This review identified a number of remaining diagnostic gaps, including lack of point-of-care testing, difficulties obtaining clinical specimens and limited understanding of viral diversity, infection kinetics or dynamics, and ecology of the wild life reservoir; target product profiles for NiV diagnostics should be refined accordingly.
• Development of more reliable diagnostics will be key to the prevention and management of NiV disease, and to implementation of a ‘One Health’ approach comprising both human and animal surveillance and intervention.

Meanwhile the Ministry of Health's most recent press release contains additional details on the patient, and his activities for the 11 days between developing symptoms (May 23rd) and being diagnosed (June 3rd).

Case of NIPAH in Ernakulam district, Kerala, June, 2019

Mr Gokul Krishna Dileep, 21 year old male resident of Paravur, a student at Thodupuzha, district Idukki, presenting with fever on 23 rd May 2019, while in District Thrissur.

He visited a physician in Thrissur but returned to his family in Ernakulum as fever was high grade and was not subsiding. He consulted private hospital in Ernakulum on 25 May, 2019 and was treated with antibiotics.

He was referred to another private hospital on night of 30 May, 2019 as he developed slight disorientation and gait imbalance. Throat swab, CSF blood and urine samples were sent to National institute of Virology Alapuzha on 2 June, 2019.

The samples were sent to NIV Pune on 3 June, 2019 for confirmation and tested to be Nipah positive. The patient is stable conscious and oriented at present. All 3 other family members are healthy.

According to this press release, at least 314 contacts are being followed up on daily basis.  This number, and the number of `suspect' cases, will likely fluctuate a good deal in the days to come, as authorities evaluate potential exposures. 
 
While novel influenza remains the world's biggest pandemic threat, over the past couple of decades Nipah, SARS, MERS-CoV, and other suspected bat-borne viruses have become increasingly viewed as having some pandemic potential.

In Steven Soderbergh's 2011 pandemic thriller `Contagion’, technical advisor Ian Lipkin - director of Columbia University’s Center for Infection and Immunity in New York - painstakingly created a fictional MEV-1 pandemic virus based on a mutated Nipah virus.

•  In 2015's Blue Ribbon Study Panel Report on Biodefense a bi-partisan panel described a fictional biological attack on Washington D.C.  using a genetically engineered Nipah virus as part of their presentation. 
• A year ago, in the Johns Hopkins Clade X exercise, a genetically altered Nipah virus (spliced onto a parainfluenza backbone) was the cause of their fictional pandemic.  
• And early last year, in WHO List Of Blueprint Priority Diseases, we saw Nipah and Henipaviral diseases listed among the 8 viral threats in need of urgent accelerated research and development.

Earlier this year, in Curr. Opinion Virology: Viruses In Bats & Potential Spillover To Animals And Humans, we looked at an excellent overview of bat viruses with zoonotic potential.

While none of these viruses currently appear to be ready for prime time, bat-borne viruses are increasingly on our radar.  Some past blogs include:

Back To The Bat Cave: More Influenza In Bats

EID Journal: A New Bat-HKU2–like Coronavirus in Swine, China, 2017

Emerg. Microbes & Infect.: Novel Coronaviruses In Least Horseshoe Bats In Southwestern China

SARS-like WIV1-CoV poised for human emergence