Vaccination against cholera can play a vital role in cholera outbreak prevention. Being a cholera endemic country, it is right time for Nepal to submit a request form for cholera vaccine to the WHO’s Global Task Force on Cholera Control

On June 3, a 40-year-old female from Nuwakot visited the emergency ward of Sukraraj Tropical and Infectious Disease Hospital (STIDH). Her chief complaints were loose motion, abdominal pain and vomiting. Faecal specimen tested positive for Vibrio cholerae O1 Ogawa serotype by stool culture. It was later reconfirmed by the National Public Health Laboratory. Similarly, a 36-year old male from Kalimati area had a two-day history of acute watery diarrhoea, vomiting, abdominal pain and leg cramps. He was admitted to STIDH on June 11. He was also tested positive for cholera (O1, Ogawa serotype). On June 17, two other patients with acute diarrhoea were found positive for similar types of cholera.

These are the first reported cases of cholera this year (2018). For the past few years, cholera has been regularly seen in Kathmandu.

Cholera is an acute infectious disease caused by the bacterium called Vibrio cholerae. If not treated within hours, it can lead to severe dehydration, unconsciousness or even death. A person with cholera develops signs and symptoms in between 12 hours and five days after ingesting contaminated food or water. Nevertheless, only about 1 in 10 infected will have a severe illness such as profuse watery diarrhoea, abdominal pain, vomiting and leg cramps.

It is worth mentioning here that remaining infected persons but without having signs and symptoms of cholera, however, can still shed this bacterium in their faeces in 1 to 10 days after infection.

In Nepal, most of the people do not usually visit hospital unless signs and symptoms are severe. Thus these majority asymptomatic infected persons can be the cause of the spread of this deadly bacterium. Even after a single case is detected, concerned bodies should spring into action and launch campaigns, especially preventive measures against cholera. We should not wait for an outbreak in some other parts. Cholera is usually observed during rainy seasons. In Nepal, the rainy season generally begins in mid-June and lasts until the first week of September.

For the last few years, cholera cases have been found between July and October in Kathmandu. This year, the first cholera cases, however, were detected at the beginning of June – earlier than expected. Knowledge of the changing epidemiology trends of cholera over the time is crucial and helpful to clinicians and policymakers.

For the first time, STIDH observed a new biotype of cholera known as “Classical biotype” in humans in Nepal. In fact, “Classical biotype” is thought to be extinct and has not been detected for the past several years worldwide. Two types of biotypes known as “El tor” and “Classical” are associated with serogroup O1 cholera.

El tor biotype has been solely detected in Nepal in the past. O1 and O139 serogroups are primarily responsible for cholera outbreaks worldwide. Classical biotype is found to be associated with higher case-to-infection ratio compared to El tor biotype. Thus, a careful laboratory-based study is necessary in order to predict outcome and severity of cholera in coming days.

The government has been heavily investing in how to practice good and effective personnel hygiene such as hand washing techniques for the prevention of cholera. Though hand washing is still important, other new routes of transmission of cholera are emerging in Nepal.

For example, cholera from jar water was first identified at STIDH in 2015 – a new route of transmission of cholera bacterium

Very recently, Nepal Academy of Science and Technology has documented that harmful pathogens are found in abundance in commercial jar water. Likewise, unwillingness to boil water due to losing its original taste is becoming one of the main challenges when it comes to fight against cholera. One cholera patient told me that he usually does not boil water due to its unpleasant taste, although he knows he has to boil it before using it for drinking. Such mindset has to be addressed while campaigning against waterborne diseases including cholera.

Cholera is a well-established waterborne infectious disease in Nepal, and its economic and social burden is enormous. Sometimes, it is difficult to diagnose cholera earlier due to various reasons.

Recently, WHO’s Global Task Force on Cholera Control partners endorsed a call to action on ending cholera through the implementation of “Ending Cholera – A Global Roadmap to 2030”. Cholera-affected countries have been urged to put extra efforts and resources to end cholera transmission. In this context, vaccination against cholera can play a vital role in cholera outbreak prevention. Being a cholera endemic country, it is a right time for Nepal to submit a request form for cholera vaccine to Global Task Force on Cholera Control.

According to Global Task Force on Cholera Control, “A cholera outbreak is defined by the occurrence of at least one confirmed case of cholera and evidence of local transmission”. This clearly shows there is a cholera outbreak already in the country this year.

There is a need to maintain extra vigilance against cholera to prevent further spread of the disease and to bring outbreaks under control, if it occurs.

Pun is coordinator of Clinical Research Unit, Sukraraj Tropical and Infectious Disease Hospital