Lingering pathogens are pathogenic influences that remain in the body and provoke a persistent immune response that produces characteristic signs and symptoms. Pathogenic influences in this context include living organisms (viruses, bacteria, fungi and parasites) as well as allergens, chemicals, drugs and environmental toxins.
Lingering pathogens manifest in a number of ways. An infection from the past may still be making its presence felt with recurrent symptoms (often arising when the patient is stressed or run down), or is perhaps detectable as persistent antibodies or other markers, in blood tests. Examples include glandular fever (Epstein Barr virus), cytomegalovirus, toxoplasmosis, brucellosis, aspergillus, malaria, viral hepatitis, and the active factors in immunizations. Some natural fauna can also manifest as lingering pathogens if they are not maintained in proper balance.
In clinic we often suspect a lingering pathogen when the patient presents with a history that begins “I have never been well since…”. They are usually referring to an acute infection they suffered some time ago, and occasionally an immunization. Alternatively, the initial insult which has left the patient with chronic or recurrent symptoms may have been exposed to environmental toxins such as volatile gases, fumes or heavy metals, or in some cases drugs or substances causing an allergic reaction.
In some cases, the initial infection or injury is not recalled or apparent, however the pattern of recurrent symptoms fits the picture of a lingering pathogen and will be treated as such.
There are a number of signs and symptoms that point to the presence of a lingering pathogen. Not all will be present in any particular individual, and their appearance can vary depending on any complicating pathology or deficiency, the duration of the condition, the age of the patient and any medications the patient may be taking.
A thorough physical examination is essential in the discovery of lingering pathogens, as signs like abnormal heat distribution or isolated sweating may be quite subtle and not obvious to the patient. The golden rule is that while patients are often unreliable witnesses, the body never lies. A good physical examination, in the context of lingering pathogens, requires systematic assessment of the neck for lymphadenopathy, observation of the tonsils for swelling, and palpation of the skin of the arms and hand, chest, head and feet for abnormal temperature sensations and moisture.
A positive history of infection or other event (immunization, chemotherapy) from which the patient has never completely recovered, or following which has been ‘never well since’ is the strongest indicator that a lingering pathogen is in situ. In such cases, the lingering pathogen may be present as a persistent illness after the initial episode has passed, or as an ‘echo’ of the initial illness that appears from time to time, recurring in much the same fashion as the first episode, although generally less severe, and usually when the patient is run down or stressed.
The sudden onset of an uncharacteristic symptom, in some absence of any clear etiology, may suggest a possible pathogenic influence. This is seen most commonly in middle aged people who suddenly develop an uncharacteristic problem, such as insomnia, headaches, asthma or allergies, with no identifiable changes in diet, habits, environment, routine or relationships to explain it. In such cases, a lingering pathogen should be part of the differential diagnosis.
Lingering Pathogens Part Two: Signs and Symptoms