We’re staring at a crisis. The cholera bug is mutating fast. The disease outbreaks are more frequent. The drugs don’t work any more.
From January to April this year alone, the World Health Organisation announced outbreaks in 21 countries in eastern and southern Africa.
It has already been established that the frequency of outbreaks has increased, and this is a regional problem. Angola, Burundi, Kenya, Malawi, Mozambique, Tanzania, Somalia, Uganda, Zambia and Zimbabwe have had cholera cases since the beginning of 2019, according to WHO.
Kenya accounts for 35 per cent of the cases reported this year, followed by Mozambique (31 per cent). Tanzania and Burundi recorded the highest number of deaths in 2019 at 1.3 per cent and one respectively.
Scientists now fear the cholera bug has evolved to become stronger and harder to kill. In true biblical style, no weapon fashioned against it by scientists has prospered.
Cholera is caused by a bacteria called Vibrio cholerae through consuming contaminated food or water. Once in the stomach, the pathogen peels the lining of the stomach, causing diarrhoea that looks like rice water.
In Uganda, the Health ministry tested the strain of cholera responsible for the 2015-2016 outbreak and found it was resistant to Ampicillin (an antibiotic), according to BMC Infectious Diseases.
An analysis of data from 2011 to 2016 showed that Arua, Zombo, Nebbi, Ntoroko, Hoima, Masindi, Bulisa, and Busia were among the high risk areas.
In 2018, other districts like Bundibugyo, Bulambuli, Kasese, and Kyegegwa were also marked as hotspots.
At least 11,030 cases of cholera were reported between 2011 and 2016. The highest number of cases were 6,226 in 2012 and the lowest were 229 in 2011.
A study conducted in Bulambuli district in Eastern Uganda near the border with Kenya, whose results were published in June, concluded that the cholera outbreak in that area was caused by drinking contaminated water from Cheptui River.
The Tanzanian National Health Laboratory Quality Assurance and Training Centre in Dar es Salaam tested more than 511 stool specimens from 2015 to 2016, and resistance was detected to two antibiotics — Nalidixic acid and Ampicillin. These were outbreaks that caused more than 270 cases each week mostly in Dar es Salaam, Morogoro, Mwanza, and Mara.
New cases emerged from Tanga region in Korogwe DC (24), Korogwe TC (11) and Handeni (3). Cumulatively, the country has registered a total of 33,475 cases, with 552 deaths since the beginning of the outbreak in August 2015.
In Kenya, which accounts for more than a third of the cholera cases in the 21 African countries, the resistance is taking a dreaded turn.
From 2015, Nairobi’s neighbourhoods such as Zimmerman began recording cases of cholera.
Unaware of the mutating bug, public health officials issued statements about the usual: wash your hands, a call on the government to supply cleaner water because cholera thrives in dirt and advice to seek medical attention fast.
Dr John Kiiru, an expert on infectious diseases at Kenya Medical Research Institute, says the bacteria have “reinvented themselves” to become deadlier.
These changes have allowed the bacteria to adjust their genetic make-up in order to adapt easily to changes in climate and resist medication.
The bacteria in the current wave of outbreaks are more resistant to drugs than the germs encountered in the 90s and 80s. The bug is stronger and faster in causing outbreaks. “Before 2005, major cholera outbreaks would be experienced after a period of three to four years. But, since then, outbreak cycles are two to three months apart,” says Dr Kiiru, adding that “the whole of 2017 was a cholera year”.
Things took a significant turn after the 1997/99 El Niño/La Niña cycle. During this period, 26,901 cases were reported, resulting in 1,362 deaths. The deaths accounted for 5.1 per cent of the cases, which is five times the globally accepted maximum.
Dr Kiiru’s team noticed that the changes in the genetic composition of the cholera bacteria started in 2012. This was when his team in Kemri first isolated a strain that was resistant to a class of drugs traditionally used for early management of cholera. But, the first major outbreak caused by this mutant strain was recorded in 2015.
“We have since observed a gradual, but sustained replacement of the traditionally easier-to-treat cholera strains with this resistant strain,” he says.
Cholera is now worrying everyone and is no longer seen as a disease of the poor. The bug has gone to areas where it wasn’t previously found such as Central Kenya. Traditionally, cholera is common in low-lying areas such as coastal regions or near Lake Victoria where flooding is rampant and water drainage is poor. Cholera is also more common in urban slums, but the current strain is wreaking havoc in middle-income neighbourhoods.
Since January, Kenya has reported 4,171 cases of cholera and 28 deaths.
Apart from slums in Mukuru kwa Reuben, Kibera and Kayole, Nairobi County cases were found in Tassia, Donholm and pockets of Starehe and Ruaraka.
Prof Gunturu Revathi, the head of microbiology at the Department of Pathology at Aga Khan University Hospital says cholera is now “endemic and resident in the city”. “You can see happy, healthy looking people in Nairobi with cholera in their gut shedding it to the environment,” she says.
She makes fun of the drainage system which “was developed during Queen Victoria’s era, not even the current Queen Elizabeth’s”. “So, whenever it rains heavily in Nairobi, the drinking water is contaminated and people fall sick with diarrheal attacks,” she adds.
Prof Revathi comes across at least one cholera case daily in her lab.
Dr Kiiru says: “The patients shed the bacteria in millions from their gut, people carry the bacteria on their hands every time they visit a washroom, those who have not been exposed to the bacteria before and have not developed any rudimentary immunity against the cholera are caught off guard.”
Cholera was first reported in 1836 in Africa in Zanzibar. The 20,000 people who died came from as far as Lamu, Malindi and Kilwa in Kenya. Before that, the disease had been in Asia in 1817. Those cholera cases were mainly due to drinking water polluted by human waste. A total of 30,000 people were killed in Egypt in 1840 and more in West Africa until 1897. Perhaps plotting a deadlier war, the bug went silent before resurging in 1970.
WHO has reported that 99 per cent of cholera deaths are from Sub-Saharan Africa. The deaths in Africa have been blamed on fragile health systems, poor sanitation and political crises that drive people to overcrowded refugee camps. While the incidence of cholera has reduced by 23 per cent, WHO reports, the number of people who die out of those diagnosed in any outbreak has doubled from one to about two.
Until 2012, public health experts in Kenya were sure they had the disease figured out. They were wrong.
From one outbreak to the next, Dr Kiiru had been studying the bacteria, and all had been fine until 2012. “Now, it has acquired certain types of plasmids,” he says.
Plasmid. What a small word for the terror it symbolises. Plasmids are mobile elements, which attach themselves to the bacteria. Plasmids help bacteria perform certain functions for their survival.
“If you have one bacterium that has a plasmid that is resistant to a drug, the bacterium with that plasmid quickly shares the plasmid with those that do not have the element as soon as you subject them to antibiotics. Thus, the more we misuse antibiotics, the more we encourage resistant bacteria to share plasmids with those that are not,” he says.
The Vibrio cholera is a clever thief. Besides the resistance it has acquired from other sources, the arsenal it uses to cause havoc has been stolen from a group of viruses known as bacteriophages, making it a potential super pathogen resistant to antibiotics.
A study published in Nature by the Kemri team and experts from the UK, India, and elsewhere showed the cholera strain currently in Kenya is also distantly related to the one behind major outbreaks in Haiti after the earthquake of 2010 and it is also a distant relative of those devastating Yemen.
Dr Kiiru terms it a genetic re-assortment of sorts, where all the bacteria sit together and ‘marry’ each other to form a newer, stronger pathogen.
Not all bacteria is bad. Good bacteria tirelessly labour to cycle nutrients. Organic carbon, the rotten food in garbage cans, would quickly deplete the carbon dioxide in the atmosphere if not for the activity of decomposing bacteria. Without carbon dioxide, there would be no photosynthesis in plants to make their food by using the sun. No food, no mankind.
However, there should be a balance between the good and bad bacteria. When the good bacteria become more and tip the see-saw on one hand, the result is sickness and death.
In Nyanza’s Ahero, despite the swampy areas which make the region prone to outbreaks, people have developed a form of immunity due to constant exposure.
In hilly areas like Central, Dr Kiiru says, ponds have become a breeding ground for cholera. “The bacteria attaches itself to fish scales and when not handled or cooked well, they cause an outbreak,” he says.
The Kemri team says the virulence and resistance are a cause for concern.
Dr Kiiru says the bacteria have a characteristic called ESBL that makes it able to resist the drugs. “Before 2012, there was pre-ESBL cholera and now there is post-ESBL Cholera,” he adds.
Microbiologist Samuel Kariuki says bacteria is intelligent, perhaps more than man. “Bacteria were here before mankind, and have learnt to survive all these years,” Prof Kariuki tells HealthyNation. “This is how they gained resistance.”
Over time, bacteria have recorded what is happening around them in their DNA such as the knowledge of what tries to kill them, and how those drugs that try to kill them work. “When you expose them to subtle doses of drugs, and they feel ‘this dose is not strong enough to kill me’, they learn the attacking style of that drug, and change themselves for the next attack,” explains Prof Kariuki.
He adds: “The bug may develop ‘pumps’ to flush the drugs out or grow a thicker layer against the drug, and the next time you take medicine, the bacteria will just scoff at the drug.”
In a previous interview, Dr Evelyn Wesangula, head of the Antimicrobial Resistance programme at the Health ministry, had raised a concern about the misuse of antibiotics, where they were taken for viral ailments or doses were not completed. However, the cholera resistance to the drugs, the microbiologists say, is not because of the misuse but the management of cholera itself.
Clinicians give antibiotics, and delay in hydrating the patients.
Prof Revathi tells HealthyNation antibiotics are not helpful to prevent cases during an outbreak.
However, antibiotics are given to patients due to severe illness to cut short the time they are sick. “The doctor or healthcare worker has to make a clinical diagnosis of cholera. Due to the vomiting and diarrhoea, one has to manage the symptoms through dehydration,” she says.
Patients can lose as much as 20 litres of water a day, and this kills especially children and the elderly. The water is lost when the body tries to get rid of the bacteria.
An effective, safe and affordable oral vaccine, approved by WHO is available and some private hospitals have been immunising staff and patients. The Health ministry has not included this vaccine in its routine immunisation.
Additional reporting by Irene Abalo