Fiebre y exantema tras picadura de garrapata / Fever and rash after tick bite

Las garrapatas duras se han convertido en los principales vectores de enfermedades infecciosas en el mundo industrializado, pudiendo transmitir a través de su picadura bacterias, virus y protozoos, además de causar procesos alérgicos y tóxicos. Dentro de las enfermedades transmitidas por garrapatas, las más frecuentes en nuestro medio son: la fiebre botonosa mediterránea, la enfermedad de Lyme y la enfermedad de Debonel/Tibola. La fiebre botonosa mediterránea es la rickettsiosis más frecuente en Europa. Se ha observado un aumento de los casos en los últimos años, en probable relación con el aumento de temperatura global. (AU)

Hard ticks have become the main vectors of infectious diseases in the industrialized world, being able to transmit bacteria, viruses and protozoa through their bite, as well as causing allergic and toxic processes. Among the tick-borne disease the most frequent in our setting are boutonneuse fever, Lyme disease and Debonel/Tibola disease. Boutonneuse fever is the most common rickettsiosis in Europe. An increase in cases has been observed in recent years, probably related to the increase in global temperature. (AU)

The Characteristics and Clinical Course of Patients with Scrub Typhus and Queensland Tick Typhus Infection Requiring Intensive Care Unit Admission: A 23-year Case Series from Queensland, Tropical Australia.

Scrub typhus and Queensland tick typhus (QTT)-rickettsial infections endemic to tropical Australia-can cause life-threatening disease. This retrospective study examined the clinical course of all patients with laboratory-confirmed scrub typhus or QTT admitted to the intensive care unit (ICU) of a tertiary referral hospital in tropical Australia between 1997 and 2019. Of the 22 patients, 13 had scrub typhus and nine had QTT. The patients' median (interquartile range [IQR]) age was 50 (38-67) years; 14/22 (64%) had no comorbidity. Patients presented a median (IQR) of seven (5-10) days after symptom onset. Median (IQR) Acute Physiology and Chronic Health Evaluation II scores were 13 (9-17) for scrub typhus and 13 (10-15) for QTT cases (P = 0.61). Following hospital admission, the median (IQR) time to ICU admission was five (2-19) hours. The median (IQR, range) length of ICU stay was 4.4 (2.9-15.9, 0.8-33.8) days. Multi-organ support was required in 11/22 (50%), 5/22 (22%) required only vasopressor support, 2/22 (9%) required only invasive ventilation, and 4/22 (18%) were admitted for monitoring. Patients were ventilated using protective lung strategies, and fluid management was conservative. Standard vasopressors were used, indications for renal replacement therapy were conventional, and blood product usage was restrictive; 9/22 (41%) received corticosteroids. One patient with QTT died, and two (8%) additional patients with QTT developed purpura fulminans requiring digital amputation. Death or permanent disability occurred in 3/9 (33%) QTT and 0/13 scrub typhus cases (P = 0.055). Queensland tick typhus and scrub typhus can cause multi-organ failure requiring ICU care in otherwise well individuals. Queensland tick typhus appears to have a more severe clinical phenotype than previously believed.

Probable African Tick Bite Fever in the United States.

African tick bite fever (ATBF) is a tick-borne rickettsial disease most often observed in North American and European tourists returning home from the southern portion of Africa. Ticks infected with Rickettsia africae transmit this parasitic bacterium to humans, who subsequently develop an influenza-like illness, one or more inoculation eschars, and in some cases, a cutaneous rash. Because ATBF often presents with non-specific symptoms that suggest other infectious diseases, establishing the diagnosis may be difficult. Confirmatory assays, including serology and nucleic acid amplification, may take weeks to return and cannot help with acute treatment decisions. We present a case of a previously healthy 60-year-old woman who developed an illness strongly suggestive of ATBF after a missionary trip to Zimbabwe and discuss the disease's diagnostic challenges. Our paper also reviews the epidemiology of this disease and the currently available diagnostic laboratory tests and recommended treatment options.

The epidemiology and clinical features of rickettsial diseases in North Queensland, Australia: Implications for patient identification and management.

BACKGROUND: Rickettsial infections are a common cause of hospitalization in tropical settings, although early diagnosis is challenging in the rural locations where these infections are usually seen. METHODS: This retrospective, clinical audit of microbiologically-confirmed cases of scrub typhus or spotted fever group (SFG) rickettsial infection between 1997 and 2016 was performed a tertiary referral hospital in tropical Australia. Clinical, laboratory and radiological findings at presentation were correlated with the patients' subsequent clinical course. RESULTS: There were 135 locally-acquired cases (95 scrub typhus, 37 SFG, 3 undifferentiated). There were nine hospitalizations during the first 5 years of the study period and 81 in the last 5 years (p for trend = 0.003). Eighteen (13%) of the 135 cases required ICU admission, all of whom were adults. A greater proportion of patients with SFG infection required ICU support (8/37 (22%) compared with 10/95 (11%) scrub typhus cases), although this difference did not reach statistical significance (p = 0.10). Three (8%) of the 37 patients with SFG infection had severe disease (1 died, 2 developed permanent disability) versus 0/95 scrub typhus patients (p = 0.02). Adults with a high admission qSOFA score (≥2) had an odds ratio (OR) of 19 (95% CI:4.8-74.5) for subsequent ICU admission (p<0.001); adults with a high NEWS2 score (≥7) had an OR of 14.3 (95% CI:4.5-45.32) for ICU admission (p<0.001). A patient's respiratory rate at presentation had strong prognostic utility: if an adult had an admission respiratory rate <22 breaths/minute, the negative predictive value for subsequent ICU admission was 95% (95% CI 88-99). CONCLUSIONS: In the well-resourced Australian health system outcomes are excellent, but the local burden of rickettsial disease appears to be increasing and the clinical phenotype of SFG infections may be more severe than previously believed. Simple, clinical assessment on admission has prognostic utility and may be used to guide management.