Parapertussis is a respiratory infection caused by the bacterium Bordetella parapertussis. This bacterial illness affects the lungs and is related to pertussis, commonly known as whooping cough. Both are Bordetella genus members, but Bordetella parapertussis does not produce the pertussis toxin, a key factor in whooping cough’s severity.
Symptoms and Comparison to Pertussis
The symptoms of parapertussis often begin subtly, resembling a common cold, with a runny nose, sneezing, and a mild cough, sometimes accompanied by a low-grade fever. After about one to two weeks, the cough can become more pronounced, characterized by sudden, uncontrollable bursts. This prolonged coughing can last for one to three weeks.
Parapertussis is a milder illness than pertussis, with a shorter duration. While both can cause a prolonged cough, the classic “whooping” sound that occurs during inhalation after a coughing fit is much less common in parapertussis. Vomiting after coughing, frequent in pertussis, is less often observed with parapertussis. Infants younger than six months, however, may experience a more severe course of parapertussis than older individuals. The incubation period for parapertussis is typically 7 to 10 days, with a possible range of 5 to 21 days after exposure to the bacteria.
Diagnosis and Treatment
Because the symptoms of parapertussis can mimic those of other common respiratory infections, a laboratory test is necessary for an accurate diagnosis. The primary method involves collecting a sample using a nasopharyngeal swab, inserted through the nostril to the back of the nose and throat. This sample is then analyzed using a polymerase chain reaction (PCR) test, which can detect the specific DNA of Bordetella parapertussis and differentiate it from Bordetella pertussis by identifying unique genetic markers.
Treatment for most cases of parapertussis is supportive, focusing on managing symptoms through rest, ensuring adequate hydration, and addressing any fever. Antibiotics, such as macrolides like erythromycin, clarithromycin, or azithromycin, or trimethoprim-sulfamethoxazole, are sometimes prescribed. These medications are most effective if administered early in the illness, within six days of cough onset, and are considered for vulnerable groups like infants. However, if not started early, antibiotics may have a limited impact on the overall course of the illness.
Prevention and Immunity
Standard pertussis vaccines, such as DTaP and Tdap, protect against Bordetella pertussis. These vaccines do not directly prevent infection with Bordetella parapertussis. While some studies suggest pertussis vaccination might offer cross-immunity or reduce parapertussis severity, other research indicates no significant protective effect. Some animal studies even suggest it could enhance Bordetella parapertussis colonization.
Transmission occurs when an infected person coughs or sneezes, releasing respiratory droplets into the air that are inhaled by others. General hygiene practices, such as frequent handwashing and covering coughs and sneezes, can help reduce bacterial spread.