How to reduce cholera-related deaths
Recent reports have associated the on-going cholera outbreaks in most parts of the world including Yemen and Nigeria to climate change and poor sanitation even as researchers warn that the situation could get worse if urgent actions were not taken.
According to the World Health Organisation (WHO), “in Africa, growing urbanization, climate change, conflict, displacement camps – as well as sanitation investment that is a third of what it should be – mean there is no reason to expect any improvement without deliberate action.”
Experts are unanimous that cholera can be prevented with improved sanitation and drinking water hygiene, factors, which have been responsible for the eradication of the illness in England for over a century. In the United States, the last cholera outbreak was almost a century ago and for many of the developed nations cholera is no longer a major threat to people’s health.
To prevent cholera, the WHO recommends:
*Good sanitation, since cholera is most commonly transmitted through drinking water that is contaminated with infected faeces. In addition to having access to good sanitation systems and clean drinking water, people should also wash their hands after using the toilet and before preparing and eating a meal.
*Surveillance and reporting of all cases of cholera. The identification, treatment and isolation of cholera prevents further spreading of the disease.
*Education of mass populations regarding good hygiene and safety practices. Such education can help contain the bacteria and prevent it from spreading.
Also, the WHO said effective and timely case management contributes to reducing mortality to less than one per cent. It consists of prompt rehydration of patients. Mild and moderate cases can be successfully treated with oral rehydration salts (ORS) only. The remaining 20 per cent of severe cases will need rehydration with intravenous fluids. Antibiotics are not paramount to successfully treat patients, but they can reduce the duration of disease, diminish the volume of rehydration fluids needed, as well as shorten duration of shedding of the germ.
The WHO noted: “Many lives can be saved if ORS is being used early at home, while waiting to get access to proper health care. WHO does not see any contradiction in making ORS packages available to households and non-medical personnel outside health care facilities. In the opposite, making ORS available at household and community levels can avert unnecessary deaths and contributes to diminishing case fatality rates, particularly in resource-poor settings. Providing nutritious food as well as continuing breastfeeding for infants and young children should continue simultaneously with administering appropriate fluids or ORS.”
Researchers at the Johns Hopkins Bloomberg School of Public Health, United States (US), in a study published last month in The Lancet Infectious Diseases noted: “Cholera is transmitted through an oral-fecal route, with outbreaks and endemic transmission tending to occur in areas with poor sanitation and a lack of clean drinking water. It affects an estimated three to five million people per year worldwide and causes 28,000 to 130,000 deaths annually. Vaccines for this illness cost an average of $1.85 per dose.”
There are two oral cholera vaccines, Dukarol and Shanchol that have been licensed for use in areas where cholera is endemic. Both vaccines contain whole-cell killed bacteria and reduce the chance of picking up cholera by more than 50 per cent for two years in endemic regions. Dukoral can be used in all age groups to provide short-term protection of up to 85-90 per cent against Vibrio cholerae 01 at four to six months following immunization. Shanchol provides longer-term protection against both Vibrio cholerae O1 and O139 in children aged less than five years.
A relatively new vaccine — internationally licensed by the WHO in 2011 — is in short supply, with roughly two million doses kept in a WHO stockpile. Current protocol calls for two doses of the vaccine to be given at least two weeks apart.
Unfortunately, these vaccines have not been widely available, have been fairly expensive for broad public health use and have been associated with a number of misconceptions, including that they do not work well.
Oral vaccines for cholera, which are composed of killed, whole cells of the bacteria Vibrio cholerae, became commercially available shortly after their development in the 1980s.
Studies have suggested a wide range of how well these vaccines provide protection, with some results suggesting that the risk of cholera is cut in half with the vaccine and others suggesting that risk is nearly eliminated.
The Guardian investigation revealed that Nigeria needs not less than N51.8 billion to procure vaccines for 70 million Nigerians at the cost of N1480 for the recommended two doses per person, which is about one-third of the 2017 national health budget of about N333 billion.
An estimated five to 10 percent of people who develop the cholera infection in their intestines will have severe disease characterized by excessive diarrhea, vomiting and leg cramps. The rapid loss of body fluids leads to dehydration and shock and, without treatment, death can occur within hours.
Several studies have shown that there is virtually no cholera in the US and UK as it tends to be transmitted by unclean water and poor sanitation practices.
Researchers say the key to eradicating cholera is upgrading water and sanitation. They say the vaccine is supposed to be a stopgap measure until sustainable infrastructure improvements can be implemented.
The WHO had in July 2017 raised red alert for acute outbreaks of cholera in Nigeria. The WHO blamed the cholera outbreaks on lack of access to clean drinking water and poor hygiene conditions.
A leading humanitarian medical organisation Medecins Sans Frontieres/ Doctors without Borders (MSF) reported Tuesday that no fewer than 48 persons have died of cholera since the outbreak of the disease last month in Borno State.
The United Nation (UN) apex health body, WHO, noted: “Poor sanitation conditions observed in the affected communities are one of the predisposing factors for this cholera outbreak. An important risk factor is the lack of access to clean drinking water and poor hygiene conditions.”
The WHO, last month, announced a strategy to stop cholera transmission by 2030, as an unprecedented outbreak in Yemen raced beyond 700,000 suspected cases with little sign of slowing down.
The WHO is also trying to keep the lid on a flare-up in Nigeria while tackling many entrenched outbreaks in Africa and an epidemic in Haiti, where almost 10,000 people have died since 2010.
The cholera focal point at WHO’s department for pandemic and epidemic diseases, Dominique Legros, said: “Once it’s out of the box, once it has spread, it’s very, very difficult to contain and we have a huge number of cases and deaths. It spreads like a forest fire.”
Legros said epidemics often arise in war zones. The WHO is sending an expert to Bangladesh to assess the risk for Rohingya Muslims fleeing from violence in Myanmar. “The risk is probably relatively high,” Legros said.
The WHO estimates there are 2.9 million cases and 95,000 deaths globally each year, far more than officially reported. Equipped with a vaccine stockpile that it created in 2013, the WHO plans to launch a global strategy on October 4.
Legros said: “The objective of the new strategy is to stop transmission by 2030. Overall, we expect reduction of mortality by 90 percent by 2030.” The strategy will aim to use the vaccine to contain outbreaks as fast as possible, while addressing deeper problems.
A new review of the research literature led by researchers at the Johns Hopkins Bloomberg School of Public Health, US, shows that cholera vaccines provide substantial protection for adults but provide significantly less protection for children under age five, a population particularly at risk for dying from this diarrheal disease.
The review, which considered seven clinical trials and six observational studies, found that the standard two-dose vaccine regimen reduced the risk of getting cholera on average by 58 percent for adults but only by 30 percent for children under age five.
The findings appear online in the journal The Lancet Infectious Diseases. Study leader and research associate in the Department of Epidemiology at the Bloomberg School, Dr. Andrew Azman, said: “There continues to be a lot of misinformation on what this vaccine is and what it can do.”
The trials and studies involved more than 500,000 thousand participants combined.
Taking an average of these results, the researchers found that for a two-dose regimen—the standard for these vaccines — efficacy was 58 percent and effectiveness was 76 percent. However, for children younger than five, efficacy was substantially lower: around 30 percent. One dose of these vaccines appeared to provide similar protection as a two-dose regimen, at least within the six months following vaccination. There were no data to examine long-term protection of a one-dose regimen.
Also, to new research by the University of Liverpool has shown that the impact of climate change on the emergence and spread of infectious diseases could be greater than previously thought.
The study, published in Scientific Reports, is the first large-scale assessment of how climate affects bacterium, viruses or other microorganisms and parasites (pathogens) that can cause disease in humans or animals in Europe.
There is growing evidence that climate change is altering the distribution of some diseases, in some cases causing epidemics or making diseases spread within their natural range, for example, Zika virus in South America, or bluetongue and Schmallenberg disease in livestock in Europe.
Diseases spread by insects and ticks (vector-borne diseases) were found to be the most climate sensitive, followed by those transmitted in soil, water and food. The diseases with the largest number of different climate drivers were Vibrio cholerae (cause of cholera), Fasciola hepatica (cause of liver fluke), Bacillus anthracis (cause of anthrax) and Borrelia burgdorferi (cause of tickborne Lyme disease).
Zoonotic pathogens – those that spread from animals to humans – were also found to be more climate sensitive than those that affect only humans or only animals. As 75 per cent of emerging diseases are zoonotic, emerging diseases may be particularly likely to be impacted by climate change.
However, the researchers stress that their response to climate change will also be dependent on the impacts of other drivers, such as changes to travel and trade, land-use, deforestation, new control measures and the development of antimicrobial resistance.
Also, another study found that cholera incidence in Africa increases during El Niño.
El Niño describes the unusual warming of surface waters along the tropical west coast of South America. These events tend to occur every three – seven years; something many suggest have become more regular and extreme in recent years, as a result of climate change.
Meanwhile, another research highlighted how El Niño could be transporting and spreading waterborne diseases like cholera thousands of miles, across oceans, with significant impacts for public health.
The study, published in the prestigious journal Nature Microbiology from a team of international researchers in the UK and US, explores how the arrival of new and devastating Vibrio diseases in Latin America has concurred in both time and space with significant El Niño events.
New Johns Hopkins Bloomberg School of Public Health research suggests that cholera cases in East Africa increase by roughly 50,000 during El Niño, the cyclical weather occurrence that profoundly changes global weather patterns.
The findings, researchers say, could help health ministries anticipate future cholera surges during El Niño years and save lives.
The researchers, reporting April 10 in the Proceedings of the National Academy of Sciences, used sophisticated mapping to pinpoint the location of clusters of cholera cases before, during and after El Niño years. Cholera is an infectious and often fatal bacterial disease, typically contracted from infected water supplies and causing severe vomiting and diarrhea. Africa has the most cholera deaths in the world.
Also, people with blood type O often get more severely ill from cholera than people of other blood types. New research from Washington University School of Medicine in St. Louis may explain why.
In people with blood type O, scientists found that cholera toxin hyperactivates a key signaling molecule in intestinal cells. High levels of that signaling molecule lead to excretion of electrolytes and water – in other words, diarrhea. Cholera is marked by severe diarrhea that can lead to dehydration, shock and even death.
The findings are available online in The American Journal of Tropical Medicine and Hygiene.
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