Monday, February 07, 2011

Bangladesh: Updating The Nipah Outbreak

 


# 5295

 

 

Although Bangladesh’s Institute of Epidemiology Diseases Control and Research (IEDCR) is calling the outbreak of Nipah at Hatibandha `under control . . . at least for the time being’, there are fresh reports of new Nipah-like illnesses occurring elsewhere in the northern region of that nation.

 

Two reports, from yesterday and today by bdnews24, followed by some background on the Nipah virus.

 

'Nipah seems under control'

Sun, Feb 6th, 2011 5:57 pm BdST

Dhaka, Feb 6 (bdnews24.com) – The spread of Nipah virus at Hatibandha in Lalmonirhat appears under control 'for the time being' as there is no report of fresh infection, says the Institute of Epidemiology Diseases Control and Research (IEDCR).

(Continue . . . )

 

 

Nipah spreading across northern region

Mon, Feb 7th, 2011 7:50 pm BdST

Dhaka, Feb 7 (bdnews24.com) –The highly fatal nipah virus is spreading across the northern region after infecting 24 people at Hatibandha in Lalmonirhat district where it seemed to be petering out.

(Continue . . .)

 

 

Nipah is a relatively recently discovered zoonotic emerging infectious disease (EID).  Zoonotic diseases are caused by pathogens that can be shared between humans and vertebrate animals.  

 

Over the past three decades we’ve seen roughly one new emerging zoonotic disease per year.

 

HIV, Lyme Disease, Avian Flu, Nipah, Hendra, Q Fever, brucellosis, leptospirosis, plague, shigellosis, rabies, Crimean-Congo hemorrhagic fever, Ebola and Rift Valley fever are all examples of zoonotic diseases.

 

Nipah (which is closely related to the Hendra virus) was first identified in Malaysia in 1998, after an outbreak that was first associated with pigs, and then linked to fruit bats.  

 

The World Health Organization describes the virus on their Global Alert and Response (GAR) Nipah Page.

 

Nipah Virus (NiV) Infection

Photo by Chi Liu

Grey-headed flying foxes (Pteropus poliocephalus)

Nipah virus (NiV) infection is a newly emerging zoonosis that causes severe disease in both animals and humans. The natural host of the virus are fruit bats of the Pteropodidae Family, Pteropus genus.

 

NiV was first identified during an outbreak of disease that took place in Kampung Sungai Nipah, Malaysia in 1998. On this occasion, pigs were the intermediate hosts. However, in subsequent NiV outbreaks, there were no intermediate hosts. In Bangladesh in 2004, humans became infected with NiV as a result of consuming date palm sap that had been contaminated by infected fruit bats.

Human-to-human transmission has also been documented, including in a hospital setting in India.

 

NiV infection in humans has a range of clinical presentations, from asymptomatic infection to acute respiratory syndrome and fatal encephalitis. NiV is also capable of causing disease in pigs and other domestic animals. There is no vaccine for either humans or animals. The primary treatment for human cases is intensive supportive care.

 

image

 

 

CIDRAP has a nicely done Overview of the Nipah Virus including the clinical symptom chart below:

 

image

 

 

The Nipah virus, like it’s cousin the Hendra virus, is classified as a biosecurity level 4 (BSL-4) agent.

 

Exactly how the Nipah virus is transmitted from human-to-human isn’t well understood, although it is thought to be mostly through direct contact with respiratory secretions or other bodily fluids.

 

In 2007 researchers published a study that looked at an outbreak in a Bangladeshi village during 2004, that found evidence of H-2-H transmission.  The following comes from the CDC EID Journal.

 

 

Volume 13, Number 7–July 2007
Research

Person-to-Person Transmission of Nipah Virus in a Bangladeshi Community

Emily S. Gurley,Joel M. Montgomery, M. Jahangir Hossain, Michael Bell,Abul Kalam Azad, Mohammed Rafiqul Islam, Mohammed Abdur Rahim Molla, Darin S. Carroll,† Thomas G. Ksiazek, Paul A. Rota, Luis Lowe, James A. Comer, Pierre Rollin, Markus Czub,Allen Grolla, Heinz Feldmann, Stephen P. Luby, Jennifer L. Woodward, and Robert F. Breiman

Abstract


An encephalitis outbreak was investigated in Faridpur District, Bangladesh, in April–May 2004 to determine the cause of the outbreak and risk factors for disease. Biologic specimens were tested for Nipah virus. Surfaces were evaluated for Nipah virus contamination by using reverse transcription–PCR (RT-PCR).

 

Thirty-six cases of Nipah virus illness were identified; 75% of case-patients died. Multiple peaks of illness occurred, and 33 case-patients had close contact with another Nipah virus patient before their illness. Results from a case-control study showed that contact with 1 patient carried the highest risk for infection (odds ratio 6.7, 95% confidence interval 2.9–16.8, p<0.001).

 

RT-PCR testing of environmental samples confirmed Nipah virus contamination of hospital surfaces. This investigation provides evidence for person-to-person transmission of Nipah virus. Capacity for person-to-person transmission increases the potential for wider spread of this highly lethal pathogen and highlights the need for infection control strategies for resource-poor settings.

 

Interestingly, while most human infections present primarily with encephalitic symptoms, those few who develop respiratory difficulties appear to be the ones most able to infect others – raising the possibility of large-droplet transmission.

 

 

 

The following, again, comes from the EID journal.

 

Volume 15, Number 8–August 2009
Research

Recurrent Zoonotic Transmission of Nipah Virus into Humans, Bangladesh, 2001–2007

Stephen P. Luby, M. Jahangir Hossain, Emily S. Gurley, Be-Nazir Ahmed, Shakila Banu, Salah Uddin Khan, Nusrat Homaira, Paul A. Rota, Pierre E. Rollin, James A. Comer, Eben Kenah, Thomas G. Ksiazek, and Mahmudur Rahman

Abstract

Human Nipah outbreaks recur in a specific region and time of year in Bangladesh. Fruit bats are the reservoir host for Nipah virus. We identified 23 introductions of Nipah virus into human populations in central and northwestern Bangladesh from 2001 through 2007.

 

Ten introductions affected multiple persons (median 10). Illness onset occurred from December through May but not every year. We identified 122 cases of human Nipah infection. The mean age of case-patients was 27 years; 87 (71%) died. In 62 (51%) Nipah virus–infected patients, illness developed 5–15 days after close contact with another Nipah case-patient.

 

Nine (7%) Nipah case-patients transmitted virus to others. Nipah case-patients who had difficulty breathing were more likely than those without respiratory difficulty to transmit Nipah (12% vs. 0%, p = 0.03).

 

Although a small minority of infected patients transmit Nipah virus, more than half of identified cases result from person-to-person transmission. Interventions to prevent virus transmission from bats to humans and from person to person are needed.

 

 

Like all viruses, Nipah has the potential to evolve - and over time - become better adapted to its hosts.

 

Which means that it, along with a plethora of other emerging pathogens around the world, deserves both our attention and respect.

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