Investigators question the term “Australian Lyme”

In their paper, “Characterising DSCATT: A case series of Australian patients with debilitating symptom complexes attributed to ticks,” Schnall and colleagues question the use of the term “Australian Lyme.” [1] And prefer instead to refer to this condition as Debilitating Symptom Complexes Attributed to Ticks (DSCATT).

The authors looked at patients admitted to their infectious disease clinic in Australia between 2014 – 2020. “Patients were included if they had debilitating symptoms suggested by either themselves or the referring clinician as being attributed to ticks.”

They acknowledged that there are ill patients who have been seen at their infectious disease clinic who have been characterized as having “Australian Lyme” or Debilitating Symptom Complexes Attributed to Ticks.

The study included 29 patients with Debilitating Symptom Complexes Attributed to Ticks.

The authors were reluctant to diagnose their 29 referrals with Lyme disease if they did not meet the Royal College of Pathologists of Australasia [RCPA] diagnostic criteria for confirmed acute Lyme disease.

Four (16%) of the 29 referrals had at least 1 positive serological test collected > 30 days after symptom onset but did not meet the diagnostic criteria for acute infection.

Nineteen patients (66%) had positive serologies from non-NATA/RCPA-accredited institutions, such as IGeneX and Infectolabs.

The patients exhibited a range of symptoms. “Prior histories of anxiety (48%) and depression (41%) were common.” The most frequently reported symptoms included fatigue (83%), headache (72%) and arthralgia (69%).

The authors concluded their patients suffered from chronic fatigue syndrome, migraines, fibromyalgia and Medically Unexplained Illness (MUS).

“[MUS] is a new medically unexplained syndrome or an umbrella term for a range of disease or symptom processes,” wrote the authors.

Most of their patients reported successful treatment with antibiotics. “Of 25 cases with available data, 23 (92%) had previously been prescribed antimicrobials, with 53% reporting benefit from them.”

The most common antibiotics prescribed were doxycycline, azithromycin, penicillin, and roxithromycin.

Some patients were treated longer than 30 days. “The median number of antimicrobials prescribed was 2 (maximum 9), with a median duration of antimicrobial use of 3 months (maximum 24 months),” wrote the authors.

“One patient was trialled on nine separate antibiotics over a 12-month period,” they wrote. One had a PORT placed for intravenous antibiotics.

One of the patients was prescribed $1200 of atovaquone. The authors stated that atovaquone has been used for treatment for Pneumocystitis carinii pneumonia. But they failed to mention that atovaquone is also used for the treatment of the tick-borne infection Babesia microti.²

Ten (53%) of the treated patients benefited from treatment but their symptoms recurred. Two failed treatment. The actual failure rate could not be determined as the authors only had access to patients referred to their infectious disease unit.

The authors did not address the diagnostic challenges in their limitations section. There are no reliable tests for fibromyalgia, chronic fatigue, or MUS.

Authors Note: I would argue that the adage “If it looks like a duck, swims like a duck and quacks like a duck, then it probably is a duck,” is applicable as the authors dispute the term “Australian Lyme.”