Cholera – Pakistan

Hatching at a glance

In Pakistan, cholera is endemic with an epidemic threshold of a single laboratory confirmed case.

In 2022, Sindh province faces a significant increase in cholera cases with 234 laboratory confirmed cases reported between January 15 and May 27. Balochistan and Punjab provinces have also reported 31 and 25 confirmed cases of cholera respectively.

Currently, there is no evidence of cross-border spread of the disease. The risk of potential international spread exists given that Pakistan has long land borders with significant cross-border movement and several major urban centres, including the city of Karachi in Sindh province, with international transport hubs.

Description of the outbreak

On April 26, 2022, the Pakistan IHR National Focal Point reported a laboratory-confirmed cholera outbreak in Sindh Province, Pakistan. As of May 27, three provinces – Sindh, Balochistan and Punjab – had reported a total of 290 confirmed cholera cases.

The first laboratory confirmed case was reported on January 15, 2022 in Sindh province. Between January 15 and May 27, 234 laboratory-confirmed cases, with no deaths, were reported in the province. Of these cases, 126 (54%) were female and 114 (49%) involved children under the age of nine. According to the national cholera surveillance policy, specimens from children are prioritized over adults for confirmatory culture testing, which may explain the high proportion of confirmed cases in children.

As of May 27, a total of 109 samples have been tested from public water sources (fire hydrants) and individual households in Karachi city, Sindh province. Of these, results are available for 71 samples, 70% of which showed the presence of Vibrio cholerae while Escherichia coli and coliforms were detected in 55% and 90% of the samples, respectively.

Besides Sindh province, three districts in Balochistan have reported 31 confirmed cases and nine deaths, while two districts in Punjab have reported 25 confirmed cases.

Figure 1: Distribution of cholera cases in Pakistan, from January 15 to May 27, 2022 (n=290)

Cholera epidemiology

Cholera is an acute enteric infection caused by ingesting the bacteria Vibrio cholerae present in contaminated water or food. It is mainly linked to insufficient access to drinking water and inadequate sanitation. It is an extremely virulent disease that can cause severe acute watery diarrhea resulting in high morbidity and mortality, and can spread rapidly, depending on frequency of exposure, exposed population and setting. Cholera affects both children and adults and can be fatal if left untreated.

The incubation period is between 12 hours and five days after ingestion of contaminated food or water. Most people infected with V.cholerae do not develop any symptoms, although the bacteria are present in their faeces for 1-10 days after infection and are shed into the environment, potentially infecting other people. Of those who develop symptoms, the majority have mild or moderate symptoms, while a minority develop acute watery diarrhea with severe dehydration. Cholera is an easily treatable disease. Most people can be successfully treated with prompt administration of oral rehydration solution (ORS).

Cholera can be endemic or epidemic. A cholera-endemic area is an area where confirmed cases of cholera have been detected within the past three years with evidence of local transmission (cases are not imported from elsewhere). A cholera epidemic can occur in both endemic and non-endemic countries. Uninfected corpses have never been reported as a source of outbreaks.

The consequences of a humanitarian crisis – such as the disruption of water and sanitation systems or the displacement of populations to inadequate and overcrowded camps – can increase the risk of cholera transmission, if the bacterium is present or introduced.

A multi-sector approach including a combination of surveillance, water, sanitation and hygiene, social mobilization, treatment and oral cholera vaccines is essential to control cholera outbreaks and reduce deaths.

Public health response

In response to the outbreak, provincial health authorities in Sindh, Balochistan and Punjab have issued high alert notifications to concerned district health offices. The three provincial departments have also officially declared an epidemic in the affected districts.

A cholera response plan has been prepared and response activities are being implemented in the affected districts of Sindh, Balochistan and Punjab. This includes establishing sentinel surveillance sites, activating rapid response teams for case tracking, and engaging private sector hospitals to improve reporting. Material support was also provided to ensure availability of supplies including ORS, zinc, selected antibiotics and intravenous fluids for case management. Community engagement and health education messages were developed and disseminated in high-risk communities. Oral cholera vaccination (OCV) campaigns are planned in the affected areas.

WHO has provided support to health authorities in Pakistan through:

  • Advocacy and coordination through multiple high-level meetings. This includes advocating and guiding relevant authorities on the response to the cholera outbreak and providing support to the provincial cholera response cell.
  • Technical support for surveillance, case management including infection, prevention and control (IPC), data management and social mobilization.
  • Community engagement, including support for social mobilizers in highly affected districts and health awareness sessions that are conducted daily.
  • Collaboration with partners such as UNICEF at national and provincial levels for the implementation of effective water, sanitation and hygiene (WASH) interventions.
  • Conduct field visits to various hospitals to support surveillance, laboratory testing for cholera confirmation, water quality monitoring, improved IPC measurements and case management.
  • Support to affected districts with the distribution of sample collection kits, water purification tablets, ORS as well as cholera information, education and communication materials.
  • Laboratory support to civilian hospitals to take water and environmental samples.
  • Capacity building of district health management teams, health care providers and hospital focal points in surveillance, rapid response teams and in areas such as laboratory testing, IPC and case management.
  • Distribution of risk communication leaflets and awareness banners with additional materials being printed for future distribution. Development of customized standard operating procedures for faecal-oral transmitted diseases and distribution to health facilities to improve case management of cholera.
  • Applications submitted for OCV that have been accepted by the International Coordinating Group (ICG) for responsive campaigns in multiple affected areas.

WHO risk assessment

The risk of potential international spread from Sindh province exists given that the worst affected districts are located in the city of Karachi, which is an industrial center as well as a transportation hub with an airport and seaport. ; it is also the largest city in Pakistan and the capital of the province of Sindh. Currently, no international cross-border spread has been confirmed for this event. However, with continued transmission near border areas and transportation hubs, the risk of international spread cannot be ruled out.

In Balochistan province, surveillance is suboptimal, access to clean water and access to health care are limited, and affected areas are close to areas of active cross-border movements with Afghanistan and Iran.

In Punjab, although response activities are ongoing, the province is still registering an increased number of suspected cholera cases, especially in Lahore, the provincial capital and major international trading hub. Further spread to other provinces would aggravate the situation given the frequent population movements.

Necessary control measures are being implemented by national authorities with the support of WHO and partners to contain the outbreak, as described in the Public Health Response section above. However, there is a need to further strengthen surveillance by establishing systematic detection and laboratory confirmation of cholera in order to properly monitor the evolution of the epidemic and institute timely and appropriate interventions.

WHO Council

  • WHO recommends strengthening the disease surveillance system. Surveillance for early case detection, confirmation and response in other provinces and regions of Pakistan needs to be strengthened.
  • Appropriate and timely management of cholera cases should be ensured.
  • Oral cholera vaccines should be used in conjunction with improvements in WASH activities to control cholera outbreaks and for prevention in areas known to be at high risk of cholera.
  • Improving access to drinking water and sanitation infrastructure, as well as improving IPC measures in health facilities, with hygiene and food safety practices in affected communities are the means most effective in controlling cholera.
  • Risk communication and community engagement on cholera prevention and early care and treatment seeking should be provided to the population.

WHO does not recommend any travel or trade restrictions in Pakistan based on currently available information.

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