PRO/EAFR> Diphtheria – Nigeria (13): update


A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Wed 2 Aug 2023 9:25 a.m. EDT
Source: The Conversation [edited]

Diphtheria has been reported in Nigeria: more than [836] confirmed
cases as of 30 Jun 2023. There were 83 deaths among the confirmed
cases between May 2022 and June 2023. Infectious diseases expert Dr.
Oyewale Tomori explains what diphtheria is, its symptoms, and how
people can protect themselves against the disease.

What is diphtheria?

Diphtheria is a disease caused by bacteria called _Corynebacterium
diphtheriae_. The bacterium usually affects the mucous membranes of
the nose and throat, causing respiratory and skin infections.

Left untreated, diphtheria toxin spreads through the tissues of the
nose and throat as well as tissues of the heart and nerves. It can be
very hard to breathe and swallow. In severe respiratory disease, there
can be damage to the heart and nerves.

What are the common symptoms, and how bad can they be?

Symptoms of respiratory diphtheria usually begin 2 to 5 days after a
person becomes infected. Signs may include weakness, fever, sore
throat, and swollen glands in the neck. A thick, grey coating in the
throat or nose can also appear.

Skin infections caused by _C. diphtheriae_ typically consist of
shallow ulcers (sores) and do not result in severe disease.

With treatment, most people with diphtheria survive, but recovery is
often slow.

Diphtheria is fatal in about 5% to 10% of the cases. Rates of death
are higher in children under age 5 or adults older than age 40.

The lethality and symptoms of diphtheria are caused by the exotoxin
produced by the bacterium. Different strains of _C. diphtheriae_ cause
differences in lethality.

How is it spread?

People with diphtheria can spread the bacteria to others through the
air when they cough or sneeze, or if others come into contact with
their infected wounds or contaminated objects.

Asymptomatic transmission and chronic infection are also possible.

How can people protect themselves?

Diphtheria is extremely rare in countries with widespread vaccination
against the disease. Many countries with low vaccine coverage rates
and limited healthcare still experience high rates of diphtheria.

Getting vaccinated is the best way to protect against diphtheria.
Diphtheria vaccines are combination vaccines. These vaccines protect
against diphtheria and tetanus, and some also protect against
pertussis (whooping cough). People of all ages need appropriate
combination diphtheria vaccines.

You should limit contact with people who have diphtheria disease who
can spread it through coughing and sneezing. Avoid touching
contaminated wounds or objects.

How serious is the current outbreak in Nigeria? How often has Nigeria
experienced diphtheria outbreaks?

It is a serious outbreak. According to the Nigeria Centre for Disease
Control and Prevention [NCDC], between May 2022 and March 2023,
Nigeria reported 1064 suspected cases and confirmed 389 cases from 21
states. During the same period, 62 deaths were recorded, giving a
case-fatality rate of 15.9%. Sadly, only 60 (15.4%) out of 389
confirmed cases were fully vaccinated with a diphtheria
toxin-containing vaccine. [As of 30 Jun 2023, per the NCDC, suspected
and confirmed cases were 2455 and 836, respectively, from 24 states.
Deaths numbered 83 for a case-fatality rate of 9.9%, and only 181
(21.7%) out of the 836 cases were fully vaccinated. – CopyEd.TW]

The outbreak is not waning, as in June 2023 alone, Nigeria reported
439 suspected cases and confirmed 160 (36.5%) from 4 states and Abuja,
the capital. No death was recorded among confirmed cases.

During the 11-year period between 2007 and 2017, Nigeria did not
report any case of diphtheria to the World Health Organisation.
However, in 2018 and 2019, the country reported 1870 and 2289 cases,

What should the Nigerian government be doing to control the disease?

According to the UNICEF/WHO joint estimates, Nigeria’s
diphtheria-tetanus-pertussis (DTP3) coverage has been consistently
lower than 80%, ranging from 29% to 62% between 2000 and 2022.

Globally, more than half (over 50%) of the children who remain
unvaccinated for DTP3 are concentrated in just 8 countries: Nigeria,
India, the Democratic Republic of Congo, Ethiopia, Pakistan, Angola,
the Philippines, and Indonesia.

This is why Nigeria continues to report diphtheria outbreaks, long
forgotten by most countries in the world. If Nigeria is to control the
disease and prevent future outbreaks, it must increase and sustain the
level of childhood vaccination to 90% and above, far above the current
levels of less than 60%.

Nigeria must also enhance epidemiological surveillance to ensure early
detection of diphtheria cases. The country must put in place an
effective and efficient laboratory service for the rapid and reliable
confirmation of cases, as well as the identification of toxigenic _C.

There must be early and prompt reporting of cases, timely management
and treatment of cases, and adequate supply of diphtheria antitoxin.
Finally, contacts must be followed up efficiently to limit the spread
of the disease.

[Byline: Oyewale Tomori]

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