FACTSHEET: What’s to blame for Nigeria’s yearly cholera outbreak?

Each rainy season Nigerians face a higher risk of cholera. Our factsheet looks at what causes these yearly outbreaks, what makes them worse, and what’s being done to prevent them.

The death of 7 people in four communities in Nigeria’s capital Abuja in August marked the latest casualties in this year’s cholera outbreak.

Over the years cholera outbreaks seem to have become inevitable in Nigeria, especially during the rainy season. The germs that cause the disease are carried by water.

What causes these yearly outbreaks? Do living conditions in some parts of Nigeria make them worse? And are health officials tackling the outbreak differently this time around?

Our factsheet answers these questions and more.

What is cholera?

Cholera is an acute diarrhoeal disease that can kill within hours if untreated. It is caused by a bacterium called Vibrio cholerae, which infects the intestine.

The US Centers for Disease Control and Prevention (CDC) says that during an epidemic “the source of the contamination is usually the feces of an infected person that contaminates water and/or food.” The disease is therefore most likely found and spread in places where water supplies aren’t treated properly and sanitation or toilet systems are poor, according to the World Health Organization (WHO).

Cholera doesn’t often spread directly from one person to another. There’s little risk of catching the disease from casual contact with someone who is already sick.

The symptoms are vomiting and watery diarrhoea. Once a victim loses a certain percentage of their body weight, death is likely, Sunday Aderibigbe, an associate professor of epidemiology and community health at the University of Ilorin, told Africa Check.

Cholera outbreaks in Nigeria since 1970

Nigeria’s first recorded case of cholera was in village near Lagos, the country’s commercial hub, on 26 December 1970.

A major epidemic hit in 1971, with 22,931 cases reported and 2,945 people dying. The case fatality rate, or the share of sick people who died, was 12.8%.

Two decades later, in 1991, another major outbreak was reported to infected 59,478 Nigerians and killed 7,654 across the country. Historically, Kano, Katsina and Bauchi states seem to be particularly affected by cholera outbreaks.

This year 18,205 suspected cases were reported up to 29 July, including 235 deaths in 17 states. This is according to data from the Nigeria Centre for Disease Control.

Adamawa state alone has about 10% of all cases, most in communities bordering Cameroon. Children have suffered the most in the latest outbreak with those aged from one to 14 years making up 51.9% of reported cases.

“Cholera is difficult for young children to withstand at any time, but becomes a crisis for survival when their resilience is already weakened by malnutrition, malaria and other waterborne diseases,” said Unicef’s deputy representative in Nigeria, Pernille Ironside, at a media briefing during the 2017 cholera outbreak.

The disease could be more widespread. The WHO estimates that officially recorded cases represent only around 5 to 10% of actual cases.

What’s behind Nigeria’s annual cholera outbreak?

Poor sanitation

The Nigeria Centre for Disease Control says the country’s annual rainy season outbreak is largely in places with poor sanitation.

“A high proportion of Nigerians dispose waste or defecate in the open,” Prof Tanimola Akande, a public health physician and consultant at the University of Ilorin, told Africa Check.

“This happens even in cities. When rain falls, it washes these waste materials into streams. Meanwhile, streams act as a source of water for people living nearby.”

Nigeria’s 2016/17 Multiple Indicator Cluster Survey shows that just 51.6% of the 182,165 household members sampled across the country had access to improved toilets. These include pit latrines with ventilation or with a slab covering the hole. Nearly a quarter (23.5%) defecated in open places or into water bodies.

The survey is by the National Bureau of Statistics and its global health partners.

Lack of safe water

The WHO lists Nigerians’ poor access to improved water sources as another risk factor.

“Nigerians consume ‘pure water’ which isn’t pure,” Akande said. “A good number of pure water factories get water from unknown sources.” (Note: In Nigeria, “pure water” is packaged sachet water.)

This was shown by an investigative project that tested 30 sachet water brands from Lagos state in a laboratory. The project checked the chemical, physical and microbiological properties of the products to see if they met WHO standards for safe water. Half had disease-causing bacteria.

In 2016/17 only 3.7% of Nigerians had good access to water that was completely safe to drink, the Multiple Indicator Cluster Survey showed.

Migration and overcrowding

People are more at risk during cholera epidemics when they live in overcrowded places where the disease is endemic or recurring, a WHO brief says.

It adds that the people most at risk are those living in slums with poor basic infrastructure on the edges of cities, and in camps for internally displaced people or refugees.

What are health officials doing?

In previous years, prevention efforts included warning people not to eat a local salad delicacy called “Igbo Abacha”.  When flood water containing cholera germs flows to vegetable and fruit farms the produce could become a source of infection if it isn’t washed properly before eating.

This year the Nigeria Centre for Disease Control launched a national prevention campaign with international partners.

It includes educating the public in ways to prevent cholera:

  1. Ensure water is well boiled before drinking and only drink bottled water that has been properly sealed.
  2. Wash your hands often with soap and clean water. If that’s unavailable, using an alcohol-based hand sanitiser.
  3. Make sure all food is well cooked. Avoid raw food such as fruits and vegetables, unless they’ve been washed in safe water.
  4. Don’t defecate in the open or dump rubbish in public places.
  5. If anyone has sudden watery diarrhoea they must visit a healthcare facility immediately.

A cholera vaccination strategy is also being developed by the National Primary Healthcare Development Agency. This means vaccines will be available in primary health centres – the first point of healthcare for most Nigerians.

In Bauchi state alone, 600,000 people from 15 local councils were given cholera vaccines in May 2018, while 757,630 shots were sent to Adamawa state a month later as part of an emergency vaccination campaign.

But “no cholera vaccine is 100% protective and vaccination against cholera is not a substitute for standard prevention and control measures”, the US CDC warns.

Edited by David Ajikobi


Further reading:

© Copyright Africa Check 2018. You may reproduce this piece or content from it for the purpose of reporting and/or discussing news and current events. This is subject to: Crediting Africa Check in the byline, keeping all hyperlinks to the sources used and adding this sentence at the end of your publication: “This report was written by Africa Check, a non-partisan fact-checking organisation. View the original piece on their website", with a link back to this page.