Queensland tick typhus in rural New South Wales

Abstract

We report five cases of Rickettsia australis infection from southern coastal New South Wales, Australia. All patients presented with a cutaneous eruption of erythematous papules and pustules and systemic features of malaise, headache, lymphadenopathy and myalgia. Acute kidney injury (AKI) was present in two of five cases and one of five cases had acute delirium. Improvement was only seen after treatment with doxycycline 100 mg b.i.d. Positive serology for R. australis was present in four of five cases and a positive polymerase chain reaction (PCR) was seen in one of five cases. Histology showed varying features, from neutrophilic vasculitis to Sweet's syndrome and lymphocytic vasculitis. Recent significant advances in the diagnosis of R. australis infection include an eschar swab or biopsy PCR and isolation of specific Rickettsia on serology. These investigations should be considered in the presence of any of the following features: eschar at site of a tick bite or lymphadenopathy and fever with an eruption of erythematous papules and pustules.

Molecular screening of ticks for the presence of Rickettsia species: A public health concern

“…The identified ticks vectors of R. australis are Ixodes tasmani, Ixodes holocyclus, and Ixodes cornuatus and these ticks are distributed along the eastern states of Australia [14,15]. R. akari, a well characterized member of the spotted fever group Rickettsia is the ethiologic agent of rickettsialpox, a benign zoonotic illness which has similar clinical manifestation like that of murine typhus.…”

Dermatological aspects of ticks in Australia: An update

“…14 The following three species of local ticks transmit bacterial agents following a tick bite: the paralysis tick (I. holocyclus) is endemic on the east coast of Australia and is associated with Queensland tick typhus (QTT) caused by R. australis and Q fever caused by C. burnetii. 16 Rickettsial infections are characterised by an eschar in 65% of cases; regional lymphadenopathy in 71% and a papulopustular eruption on the abdomen, limbs and acral areas is common. Constitutional symptoms may also be present.…”

“…Rickettsial ( Rickettsia spp ) infections (Queensland tick typhus, QTT; Flinders Island spotted fever, FISF; and Australian spotted fever, ASF) and Q fever (due to Coxiella burnetii ) are the only acknowledged systemic bacterial infections transmitted by tick bites in Australia 14 . The following three species of local ticks transmit bacterial agents following a tick bite: the paralysis tick ( I. holocyclus ) is endemic on the east coast of Australia and is associated with Queensland tick typhus (QTT) caused by R. australis and Q fever caused by C. burnetii 16 . Rickettsial infections are characterised by an eschar in 65% of cases; regional lymphadenopathy in 71% and a papulopustular eruption on the abdomen, limbs and acral areas is common.…”

“…QTT may be misdiagnosed as folliculitis or varicella infection and this uncommon disease may not be on the radar of clinicians in Australia today. It is treated with doxycycline 16 …”

Human Tick-Borne Diseases in Australia

“…Each case displayed complications including renal failure and severe pneumonia (McBride et al, 2007). More recently, five cases of QTT were reported from southern coastal New South Wales (Fergie et al, 2017), in which illness was characterized by a cutaneous eruption of erythematous papules and pustules as well as lymphadenopathy. Acute delirium or acute kidney injury was observed in three of the five cases.…”