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The Listeriosis outbreak is causing widespread panic and leaving death in its wake. And yet The National Institute for Communicable Diseases is yet to determine the source of the food-borne Listeriosis outbreak that has reached 748 laboratory-confirmed cases.
On Friday the institute said 67 people had been confirmed dead from the outbreak gripping the country which surfaced early last month and affects all nine provinces.
This week, Health Minister, Aaron Motsoaledi, gave a situational update of the outbreak, revealing that since the last briefing held in December, cases rose from 527 in December to 748 by Friday.
Dr Juno Thomas, head of the Centre for Enteric Diseases at the National Institute for Communicable Diseases (NICD), said this figure was “of great concern”.
“It means that the source of the outbreak is not controlled; in other words, that the contaminated food item/s are still being distributed and consumed by people countrywide,” she told City Press on Friday.
At this stage, Thomas explained, it wasn’t possible to predict the course of the outbreak.
However, based on global experience with listeriosis outbreaks, she said that such an outbreak may suddenly stop when the contaminated food item/s is no longer available. This would eliminate the Listeria bacteria from the food production environment, otherwise, the contamination would continue until investigations provided clues as to the likely source.
Thomas and her team at the NICD have identified the ST6 strain of the disease as the main course for the current outbreak out of eight other sequence types.
According to Motsoaledi, this confirmed the current working hypothesis of a single source of food contamination causing the outbreak.
Explaining the strain’s particular impact on humans, Thomas said: “In persons who develop meningitis - an infection of the brain - due to Listeria monocytogenes, the ST6 in particular causes more severe disease than the other sequence types.”
But the disease’s main victim has been babies. Infants less than 28 days old account for close to 40 percent of cases so far in the country. Infants are especially vulnerable from birth to six days after birth.
She said diagnosis at the laboratory was made through culturing Listeria monocytogenes from clinical specimens taken from ill patients, such as blood, cerebrospinal fluid (CSF), amniotic fluid, placenta or sterile body fluids.
Due to the rapid spread and the unusual behaviour of the disease, it has now been classified as a priority which requires medical professionals to immediately report it to the department. Prior to this outbreak, medical staff treated about 80 cases annually that were not severe.
Last month, environmental health practitioners from the City of Tshwane investigated a Tshwane patient hospitalised with Listeriosis and collected a chicken sample from the fridge at the patient’s home.
It tested positive for Listeria monocytogenes. The sample was traced back to the store, and back to the Sovereign Foods’ abattoir from which it was sourced.
As a precaution, the abattoir was served with a prohibition notice pending further investigations.
However, following whole-genome sequencing on the abattoir-related samples (a DNA-fingerprinting analysis to see whether particular organisms are related and were of the same sequence type), experts didn’t pick up the outbreak strain (ST6).
“At this juncture, we cannot conclude that the Abattoir called Sovereign Foods is the source of the present outbreak,” Mostoaledi explained.
The department said it was also an arduous process tracking the patients with confirmed cases of the disease. Currently, of the 748 labs confirmed cases, the outbreak team has only traced the outcomes of 160 patients.
According to the department, tracking the patients from the health facility that had the specimen was not easy because some did not have traceable physical addresses.
Mostoaledi said food premises within Gauteng – with the highest number of cases at 442 – would be inspected, targeting the food processing areas such as abattoirs and food retail shops.
The Director-General of the National Department of Health has formally requested food industry stakeholders to submit details of Listeria-positive food items, environmental swabs and Listeria isolates to the NICD.
And while Listeria has peaked the attention and worry of millions across the country, the department has emphasised that this is a treatable disease.
Thomas said: “Listeriosis is treated with ampicillin, an antibiotic which is available at all healthcare facilities countrywide.
“Another antibiotic called gentamicin is sometimes added to ampicillin. The treatment usually takes 2 weeks but may be longer for complicated infections.
Mom tells of sorrow at losing daughter
It’s been a month since Tanya Clack’s daughter died from listeriosis and she is still battling to come to terms with Sonette’s final tragic moments.
Clack said Sonette had displayed symptoms from November and, because of her severe illness, doctors terminated her pregnancy at 14 weeks on November 14 at Tshwane District Hospital. At the time, she had not yet been diagnosed with the disease.
Clack said her daughter was admitted to the Steve Biko Academic Hospital on December 1. She was suspected of having meningitis until the day before her death, when the diagnosis of listeriosis was made.
“She was unconscious for two or three days and her temperature was very high. She regained consciousness and, the next minute, she was dead,” said her grieving mother.
Sonette lived in Pretoria Moot, north of central Pretoria, before she died of the food-borne disease on December 9.
This week, Clack alleged that Sonette had been cruelly treated at the hospital. She said the staff didn’t listen to her when she voiced concerns about Sonette’s high temperature on December 3.
“She was red in the face and when I asked the nurse to check what was wrong, she said they had checked her at 6am. I looked at my watch and it was 11.20am. Sonette’s right arm was very swollen from the drip and the nurse simply asked me: ‘Isn’t it always like that?’”
Sonette’s two children, aged 16 and 10, are now living with Clack in Durban. She plans to take legal action against the hospital.
“I laid a complaint at the hospital and left my details, but no one has even phoned me.”
Clack alleged that the hospital did not listen to the family when they tried to give a history of Sonette’s illness.
“It’s very unfair how they treated her … they didn’t listen to us. On that Saturday morning, her temperature was very high and all they told us was that she was on antibiotics. Ok, even so, why weren’t they checking her every two hours?” Clack asked.
The director of communications for the department of health, Foster Monare, said that the department was investigating Clack’s allegations.
Facts about Listeriosis
WHAT IS LISTERIOSIS?
According to the National Institute for Communicable Diseases (NICD), listeriosis is a serious bacterial disease caused by the Gram-positive, rodlike bacterium, Listeria monocytogenes.
Infection with Listeria usually results in gastroenteritis with symptoms ranging from mild to severe. However, in people with weak immune systems, listeriosis can lead to meningitis or septicaemia.
WHO CAN GET LISTERIOSIS?
Anyone can get listeriosis. However, those at high risk are pregnant women and their unborn babies, newborn babies, the elderly and immune-compromised individuals.
It can also affect those with underlying conditions such as HIV, diabetes, cancer and chronic liver or kidney disease.
HOW IS LISTERIOSIS TRANSMITTED?
Listeriosis is spread through the ingestion of contaminated food products including raw or unpasteurised milk, and soft cheeses. It is also found in vegetables, processed foods, ready-to-eat meats and smoked fish products.
It can survive in normal temperatures associated with refrigeration (4°C). Direct contact with the organism can cause skin lesions.
WHAT ARE THE SYMPTOMS OF LISTERIOSIS?
The incubation period varies and can be between three and 70 days (median three weeks). Up to 10% of people may be asymptomatic carriers. This figure may be higher in abattoir and laboratory workers who work with Listeria monocytogenes cultures. Symptoms are usually mild and may include fever, myalgia, malaise and sometimes nausea or diarrhoea. The spread of infection to the nervous system can cause meningitis, leading to headaches, confusion, a stiff neck, loss of balance or convulsions.
HOW CAN LISTERIOSIS BE PREVENTED?
The main preventive measure is to always ensure that good basic hygiene is followed. It is recommended to thoroughly wash fruit and vegetables. Keep your fridge temperature below 4°C and freezer temperature below -18°C. People should avoid the following foods:
- Raw or unpasteurised milk, or dairy products that contain unpasteurised milk;
- Soft cheeses (for example: feta, goat’s milk, Brie);
- Foods from delicatessen counters (for example: prepared salads, cold meats) that have not been heated or reheated adequately; and
- Refrigerated pâtés.
Source: NICD
