NewsDesk @bactiman63

In a follow-up on the Nipah virus cases reported in Bangladesh in 2023, since 4 January 2023 and as of 13 February 2023, 11 cases (10 confirmed and one probable) including eight deaths (Case Fatality Rate (CFR) 73%) have been reported across two divisions in Bangladesh, according to the World Health Organization.

Image by Gordon Johnson from Pixabay

This is the highest number of cases since 2015 when 15 cases including 11 deaths were reported.

Six cases were reported from Dhaka Division including four deaths from the districts of Narsingdi (one case who died), Rajbari (four cases including three deaths) and Shariatpur (one case). Rajshahi Division reported five cases including four deaths from the districts of Naogaon (two cases including one death), Natore (one case who died), Pabna (one case who died), and Rajshahi (one case who died)

Since 2001, Bangladesh has been reporting seasonal outbreaks of Nipah virus infection between December and May, corresponding with the harvesting season of date palm sap (DPS) occurring in the country from November to March. Reported cases ranged from zero (in 2002, 2006 and 2016) to 67 (in 2004). A lower number of reported cases was observed from 2016 following an extensive advocacy campaign against the consumption of raw date palm sap.

The following public health response has been implemented by the government of Bangladesh.

Coordination:

  • The Communicable Disease Control unit and the Directorate General of Health Services (CDC-DGHS) held an emergency meeting on 28 January 2023 with all Divisional Directors, Civil Surgeons, Health and Family Planning Officers, and other public health experts to discuss and strategize the response to the outbreak.

Surveillance:

  • Outbreak investigation including contact tracing is ongoing by the National Rapid Response Team (NRRT) in collaboration with ICDDR, B.
  • CDC-DGHS, IEDCR, the Health Education Bureau, ICDDR, B, and WHO, are focusing on strengthening the existing surveillance system; formulating strategy for immediate interventions; and information, education, and communication (IEC) content for advocacy and awareness.

Case Management:

  • CDC-DGHS and the Dhaka Medical College Hospital’s senior clinicians are strengthening case management. COVID-19-designated Intensive Care Unit (ICU) beds in the hospital were repurposed temporarily for Nipah virus infection case management.
  • The infectious disease hospital (IDH) in Dhaka has been designated to support the quarantine and isolation of suspected Nipah virus infected cases.

Infection Prevention and Control:

  • Health care workers across all levels are instructed to observe optimal infection, prevention and control including wearing masks and gloves, investigating, and managing cases locally, and not referring cases to Dhaka for management except when necessary.
  • The National Guideline for Management, Prevention, and Control of Nipah Virus Infection is being reviewed and updated, focusing on safety measures for healthcare workers and infection, prevention, and control (IPC).

Risk Communication and Community Engagement:

  • Advocacy, risk communication and community engagement activities (RCCE) are ongoing.
  • Two hotline numbers have been activated for Nipah, one at IEDCR and the other at ICDDR, B, with the aim to collect formal and informal reporting of Nipah cases and also to meet the general queries of the public about Nipah and other infectious diseases.

WHO risk assessment

The overall risk is assessed by WHO as high at the national level due to the following reasons:

  1. Although Nipah virus cases are reported in Bangladesh almost every year, 11 cases and eight deaths, have already been reported in 2023, which is unusual compared to the past seven years.
  2. The case fatality rate from Nipah virus infection is high (73%). Initial signs and symptoms of Nipah virus infection are non-specific, and the diagnosis is often not suspected at the time of presentation. This can hinder accurate diagnosis and creates challenges in outbreak detection, effective and timely infection control measures, and outbreak response activities.
  3. There are currently no specific drugs or vaccines available for Nipah virus infection although WHO has identified Nipah as a priority disease for the WHO Research and Development Blueprint.  Intensive supportive care is recommended to treat severe respiratory and neurologic complications.
  4. Currently, the level of awareness among the general population is still low, despite ongoing efforts for risk communication and community engagement.
  5. There has already been one case of suspected human-to-human transmission during the current outbreak and secondary cases have previously been reported in Bangladesh.
  6. Fruit bats or flying foxes (Pteropus species.), the natural reservoir of Nipah virus, is present in Bangladesh and the genetic diversity of Nipah virus isolated from affected persons in Bangladesh suggest substantial diversity of the virus in the wildlife reservoir and repeated spill over of the virus from its reservoir to the human population.

The risk at the regional level is moderate as Rajshahi district borders India. Although there have not been any instances of cross-border transmission by humans previously, this risk remains given the shared ecological corridor for the virus’s natural host (fruit bats or flying foxes) and occurrence among domestic animals and humans previously in both countries. India also has experienced previous outbreaks of Nipah virus infection.

The risk assessed at the global level is low considering the absence of natural hosts in many countries and the fact that there have been no previous cases outside Bangladesh, India, Malaysia, and Singapore.