Diphtheria: what you need to know

With five confirmed cases of Diphtheria (Witseerkeel) in the Helderberg basin, there are a few key things you need to know about this potentially life-threatening bacterial infection.

As a modern society, we take for granted that illnesses like polio and diphtheria no longer seriously affect us, and must remember that this is largely due to effective immunisation programmes.

The vaccine for diphtheria was developed in the 1940s, and has been widely used around the world since.

As a result, diphtheria is now so rare that even as a doctor I had to double-check the spelling when researching this article.

There are usually only a handful of cases of diphtheria reported in South Africa every year.

The biggest outbreak in South Africa in recent years was in KwaZulu-Natal in 2015, in which there were 15 confirmed cases, and four reported deaths.

Further afield, a good illustration of the disease’s natural course in the face of interrupted immunisation programmes was in the former Soviet Union in 1990.

According to the South African Respiratory Journal (SARJ), 157 000 people contracted the disease, and 5 000 deaths were reported.

Immunisation in children remains the cornerstone of prevention, and in the case of diphtheria, prevention really is better than cure.

I will focus on the respiratory type, Corynebacterium Diphtheriae (medical advice: don’t try to say that with a mouth full of cereal).

Carried only in humans, this strain of diphtheria is contagious, and spreads from person to person through respiratory droplets or hand-to-mouth contact with an infected person’s mouth, nose or throat.

Symptoms usually start within two to five (up to 10) days after contact. Early symptoms and signs are nonspecific and similar to tonsillitis or other throat infections.

These include fever, malaise (feeling poorly), chills, nausea and vomiting, loss of appetite, accompanied by a sore throat. A tell-tale whitish/grey pseudomembrane may form over the throat and tonsils, which can make it difficult to swallow and breathe.

This false “membrane” looks like a lining at the back of the throat, but is in fact dead tissue, and will bleed if someone attempts to scrape it away.

It forms due to a toxin produced by the bacteria. It can cause swelling in the airways and neck lymph nodes, giving the characteristic appearance of a “bull neck”.

In severe cases, this swelling can block the airway, which can be fatal. In other severe cases, the heart muscles can become affected and may cause heart failure or cardiac arrest.

Remembering that while most pharyngitis (infection in the throat) is not diphtheria, the presence of a pharyngitis with a white/ grey pseudomembrane, with or without the “bull neck” should get medically checked out urgently.

Children who were not fully immunised are at increased risk. Whereas adults are less affected than children, they may also be at risk if exposed more than 10 years after their last booster.

If diphtheria is suspected, your doctor should take a throat swab, and treat you according to your clinical condition. It is not necessary to wait for the throat swab results before starting treatment.

Treatment requires antibiotics, though antibiotics are not enough if the “pseudomembrane” has already formed. In these cases, patients are given antitoxin and other supportive measures in hospital, which greatly improves outcomes.

As an interesting side remark, the antitoxin used during the 2015 outbreak in KwaZulu-Natal was made and donated by Japan, which is one of three countries that manufactures the antitoxin.

This apparently cost them R2 million rands for 400 vials.

The most important message with regards diphtheria is: Make sure your children (and you) are up to date with your immunisations.

Children should be vaccinated for diphtheria at six, 10 and 14 weeks, and again at 18 months. They receive boosters at ages six and 12 years old.

According to the SARJ, good immunisation schedules appear to be sufficient for keeping the toxin-producing strains out of general circulation. Immunisation programmes need 90% coverage to be effective.

Adult immunity tends to fade over 10 years, but this is generally not an issue due to low rates of transmission, thanks to effective child immunisation programmes.

Adults can choose to get a booster every 10 years, though this would only be necessary if there was a significant outbreak, and in high risk individuals (such as people who have been in contact with confirmed cases).

According to the World Health Organisation (WHO) and the United Nations Children’s Fund (UNICEF), South Africa’s immunisation rate is between 70 and 80 percent, hence the occasional outbreaks.

There are several reasons suggested for the below 90 percent coverage, including limited resources for surveillance, vaccine distribution issues (especially in deeply rural areas), children who do not attend school or clinics, and some immigrants that might be unvaccinated or avoid using government clinics.

It is important to remember that children of all nationalities are able to access free vaccination services at government clinics.

There are also several private pharmacies and clinics that offer immunisation services.

Dr HJ MacRobert is from New Street Surgery, Somerset West.