Professor, Doctor, and Physician Nguyen Thanh Bao from the Department of Microbiology at Ho Chi Minh City University of Medicine and Pharmacy stated that diphtheria is an acute infectious disease caused by the diphtheria bacteria. Anyone who comes into contact with the pathogen can become infected. Individuals with low immunity are more susceptible to the disease. Typically, children aged one to ten years are the most affected because they no longer have antibodies passed from their mothers.
Diphtheria outbreaks do not follow a distinct seasonal pattern; as long as there is a source of infection, it can spread. When an infected person coughs or sneezes, bacteria are dispersed into the air and can infect healthy individuals. Additionally, skin contact through scratches can also lead to the spread of diphtheria bacteria.
What is Diphtheria?
According to specialist in General Internal Medicine Dr. Nguyen Thi Hai Dan, diphtheria is an acute infectious disease caused by the bacterium Corynebacterium diphtheriae. The disease can lead to serious complications such as pneumonia, heart failure, nerve paralysis, and even death.
In Vietnam, although diphtheria has been controlled since the introduction of the vaccine, it has not been completely eradicated. Since 2013, sporadic outbreaks have occurred, mainly in the Central and Central Highlands regions, and more recently in Northern provinces such as Ha Giang, Dien Bien, and Thai Nguyen.
Symptoms of diphtheria primarily include sore throat. (Illustrative image: News).
Symptoms of Diphtheria
The main symptom of diphtheria is a sore throat, characterized by a white pseudomembrane caused by inflammatory cells adhering to the throat. If left untreated, this membrane can spread and block the respiratory tract, causing the patient to suffocate. Unlike other common bacteria, diphtheria bacteria can cause a sore throat, fever, and most dangerously, their toxins can enter the bloodstream and affect vital organs, leading to myocarditis and nephritis. The bacteria can even impact the nervous system, causing paralysis of the arms, legs, strabismus, and changes in the voice due to laryngeal strain.
Treatment for Diphtheria
The treatment for diphtheria involves the use of diphtheria antitoxin and macrolide antibiotics. Diphtheria antitoxin is an injectable medication containing antibodies that neutralize the diphtheria toxin, preventing damage to tissues and organs. Macrolide antibiotics such as erythromycin or azithromycin are used to kill the bacteria and prevent the spread of the disease.
When a child is diagnosed with diphtheria, parents should be vigilant in taking measures to prevent complications from the toxins produced by the bacteria. The patient needs to receive diphtheria antitoxin vaccination (Serum Anti Diphtheriae – SAD) to neutralize the bacterial toxins and prevent their effects on the heart, kidneys, and nervous system. Subsequently, the physician will prescribe appropriate antibiotics to eradicate the infection.
Causes of Diphtheria
Diphtheria is caused by close contact with respiratory secretions (directly or through droplets) or from skin lesions. Humans are the only hosts for diphtheria bacteria, with very rare cases of infection in animals. Infections can occur year-round, peaking during colder months.
Diphtheria can cause damage to the heart (myocarditis), nervous system, and kidneys. Symptoms typically appear two to five days after infection. In addition to respiratory symptoms, other complications may include seizures, paralysis of the nasal nerves, facial paralysis, eye muscle paralysis, mouth muscle paralysis, and swallowing muscle paralysis.
Preventing Diphtheria
The best prevention method is to vaccinate children three times starting at birth, with each dose spaced one month apart. After one year, a booster shot is administered, followed by another booster after five years. Dr. Bao recommends that patients with sore throat and related symptoms seek medical examination early. If the physician detects a white pseudomembrane in the throat suspicious of diphtheria, they will recommend vaccination with antitoxin to prevent complications.
Diphtheria has been referred to by various names until French physician Pierre Bretonneau named it in 1826. In 1883, microbiologist Edwin Klebs identified the causative bacteria. About a year later, bacteriologist Friedrich Loffler was the first to culture the pathogen and clarify the toxin production process. In 1890, scientists Shibasaburo Kitasato and Emil von Behring discovered that the serum of animals immune to diphtheria could treat the disease in non-immune animals.
Scientists discovered the toxic β-corynebacteriophage and its role in the period from 1951 to 1953. However, it was not until 2003 that they successfully sequenced the complete genome of Corynebacterium diphtheriae for the first time.
Diphtheria is primarily caused by the bacterium Corynebacterium diphtheriae. Other species of Corynebacterium, including C. ulcerans and C. pseudotuberculosis, can also cause the disease, but such cases are quite rare. Some strains of Corynebacterium diphtheriae produce toxins that cause diphtheria. They secrete toxins because they are also infected with a virus known as a bacteriophage.
The toxin inhibits cell protein production, destroys tissues in the infected area, and leads to the formation of a pseudomembrane in the trachea. The toxin can be transported through the bloodstream and distributed to tissues throughout the body, causing myocarditis, nerve damage, thrombocytopenia, and proteinuria.
The time from infection with Corynebacterium diphtheriae to the onset of symptoms is 1-10 days, usually 2-5 days. Some symptoms include sore throat, runny nose, difficulty swallowing, fever, and cough.
Infection occurs through direct contact with the damaged skin area of an infected person, nasal and throat secretions, airborne droplets, and sometimes even through contaminated objects. Lack of vaccination, weakened immune systems, history of eczema, unsanitary living conditions, overcrowding, and travel to areas experiencing outbreaks are factors that increase the risk of diphtheria infection.
Dr. Pierre Bretonneau named diphtheria in 1826. (Image: History of Vaccines).
The world has experienced several severe diphtheria outbreaks. In 1921, the United States reported over 200,000 cases and 15,500 deaths, prompting large-scale testing and prevention programs in schools.
In 1943, World War II caused a diphtheria outbreak in Europe, with approximately one million infections and 50,000 deaths. In the 1990s, the disease infected over 80,000 people and caused 2,000 deaths in Russia. From 2014 to 2019, diphtheria outbreaks also occurred in Indonesia, Venezuela, Haiti, and in the Rohingya refugee community in Bangladesh.
