Caracterización epidemiológica de casos humanos compatibles con rickettsiosis que consultaron a instituciones de salud del departamento de Caldas-Colombia, años 2016-2019

Introducción: Las rickettsiosis son enfermedades zoonóticas, algunos artrópodos cumplen el papel de vectores. la inespecificidad de los síntomas hace que su diagnóstico clínico sea difícil. La Inmunofluorescencia indirecta (IFI), se usa en el diagnóstico. En Colombia, a partir del 2003, ha resurgido el interés por realizar estudios en búsqueda de dicha patología. Objetivo: Caracterizar epidemiológicamente los casos humanos compatibles con rickettsiosis que consultan a las instituciones de salud del departamento de Caldas-Colombia, durante el periodo de tiempo comprendido en los años 2016- 2019. Métodos: Se realizó un estudio de diseño cuantitativo, observacional, descriptivo, con una muestra no probabilística constituida por 175 pacientes con síntomas compatibles con rickettsiosis que consultaron en diferentes municipios de Caldas- Colombia; se les realizo IFI para la detección de anticuerpos en fase aguda y convaleciente frente a Rickettsia rickettsii, Rickettsia typhi y Rickettsia felis. Resultados: El promedio de edad fue de 31 años, Los municipios con mayor proporción de casos son Belalcázar, Chinchiná, Filadelfia, La Dorada, La Merced, Manizales. El 66 % tenían mascotas, frecuentemente perros; el 12% manifiestan picaduras por artrópodos. Los signos y síntomas más frecuentes fueron: cefalea 69,7%, artromialgia 60%, fiebre 58,2%. La seroprevalencia por IgG fue del 60%, 47,9% y 24% para R. rickettsii, R. typhi y R. felis respectivamente. Cinco pacientes presentaron seroconversión frente a R. rickettsii y R. felis y uno frente a R. typhi. Conclusión: Hay evidencia de enfermedad rickettsial en el departamento, predominantemente asociada con rickettsias del grupo de las fiebres manchadas.

Characteristics of Rickettsia typhi Infections Detected with Next-Generation Sequencing of Microbial Cell-Free DNA in a Tertiary Care Hospital

We present ten patients with Rickettsia typhi infection in whom next-generation sequencing of microbial cell-free DNA (mcfDNA) was used as a diagnostic tool. Rickettsia typhi mcfDNA was detected in all cases and was more rapid and specific than rickettsial serology. Rickettsia typhi mcfDNA impacted antibiotic management in 50% of patients.

Abducens nerve palsy with associated retinal involvement secondary to rickettsia typhi infection

Objective To report a case of abducens nerve palsy with associated retinal involvement due to rickettsia typhi infection. Material and methods A single case report documented with multimodal imaging. Results A 18-year-old woman with a history of high-grade fever was initially diagnosed with typhoid fever and treated with fluoroquinolone. She presented with a 5-day history of diplopia and headaches. Her best-corrected visual acuity was 20/20 in both eyes. Ocular motility examination showed left lateral gaze restriction. Lancaster test confirmed the presence of left abducens palsy. Fundus examination showed optic disc swelling in both eyes associated with superotemporal retinal hemorrhage and a small retinal infiltrate with retinal hemorrhage in the nasal periphery in the left eye. Magnetic resonance imaging (MRI) of the brain and orbits showed no abnormalities. A diagnosis of rickettsial disease was suspected and the serologic test for Richettsia Typhi was positive. The patient was treated with doxycycline (100 mg every 12 h) for 15 days with complete recovery of the left lateral rectus motility and resolution of optic disc swelling, retinal hemorrhages, and retinal infiltrate. Conclusion Rickettsial disease should be considered in the differential diagnosis of abducens nerve palsy in any patient with unexplained fever from endemic area. Fundus examination may help establish an early diagnosis and to start an appropriate rickettsial treatment.

Abducens nerve palsy with associated retinal involvement secondary to rickettsia typhi infection

Objective: To report a case of abducens nerve palsy with associated retinal involvement due to rickettsia typhi infection Material and methods: A single case report documented with multimodal imagingResults: A 18-year-old woman with a history of high-grade fever was initially diagnosed with typhoid fever and treated with fluoroquinolone. She presented with a 5-day history of diplopia and headaches. Her best-corrected visual acuity was 20/20 in both eyes. Ocular motility examination showed left lateral gaze restriction. Lancaster test confirmed the presence of left abducens palsy. Fundus examination showed optic disc swelling in both eyes associated with superotemporal retinal hemorrhage and a small retinal infiltrate with retinal hemorrhage in the nasal periphery in the left eye. Magnetic resonance imaging (MRI) of the brain and orbits showed no abnormalities. A diagnosis of rickettsial disease was suspected and the serologic test for Richettsia Typhi was positive. The patient was treated with doxycycline (100 mg every 12 h) for 15 days with complete recovery of the left lateral rectus motility and resolution of optic disc swelling, retinal hemorrhages, and retinal infiltrate.Conclusion: Rickettsial disease should be considered in the differential diagnosis of abducens nerve palsy in any patient with unexplained fever from endemic area. Fundus examination may help establish an early diagnosis and to start an appropriate rickettsial treatment.

Murine typhus mistaken for COVID-19 in a young man

Fever is a widely recognised presenting symptom of COVID-19. Consequently, other febrile illnesses may be difficult to distinguish from COVID-19—leading to delays in diagnosis and treatment. One such illness is murine typhus, a fleaborne illness with worldwide distribution caused by Rickettsia typhi. It often presents with fever, headache and myalgia, all of which have been commonly reported with COVID-19. Although the disease is usually mild with a good prognosis, there have been reports of severe illness and death. I present a case of murine typhus in a young male who had 2 weeks of headaches and daily fevers during the COVID-19 pandemic. He was ultimately tested for murine typhus when his occupation as a dog trainer was queried, and he experienced resolution of symptoms after treatment with doxycycline. During this pandemic, clinicians must be vigilant of other febrile illnesses whose symptoms overlap with COVID-19.

The Isolation of Orientia tsutsugamushi and Rickettsia typhi from Human Blood through Mammalian Cell Culture: a Descriptive Series of 3,227 Samples and Outcomes in the Lao People’s Democratic Republic

ABSTRACT In the Lao People’s Democratic Republic (Laos), rickettsial infections, including scrub and murine typhus, account for a significant burden of fevers. The Mahosot Hospital Microbiology Laboratory in Vientiane, Laos, routinely performs rickettsial isolation from hospitalized patients with suspected rickettsioses using mammalian cell culture systems. We review the clinical and laboratory factors associated with successful Orientia tsutsugamushi and Rickettsia typhi isolations from this laboratory over a period of 6 years between 2008 and 2014. The overall isolation success was 7.9% for all samples submitted and 17.3% for samples for which the patient had a positive O. tsutsugamushi or R. typhi rapid diagnostic test (RDT), serology, or PCR. The frequency of successful isolation was highest for samples submitted in November, at the end of the wet season (28.3%). A longer median duration of reported illness, a positive result for a concurrent Orientia or Rickettsia spp. quantitative PCR, and the use of antibiotics by the patient in the week before admission were significantly associated with isolation success (P < 0.05). Buffy coat inoculation and a shorter interval between sample collection and inoculation in the laboratory were associated with a higher frequency of isolation (both P < 0.05). This frequency was highest if cell culture inoculation occurred on the same day as blood sample collection. Factors related to the initial rickettsial bacterial concentration are likely the main contributors to isolation success. However, modifiable factors do contribute to the rickettsial isolation success, especially delays in inoculating patient samples into culture.

Serosurvey of IgG Antibodies against Bartonella henselae and Rickettsia typhi in the Population of Attica, Greece

Rickettsia typhi and Bartonella henselae are the causative agents of murine typhus and cat-scratch disease, respectively. A small-scale survey (N = 202) was conducted in the Attica region, Greece, for determining the prevalence rates of IgG antibodies against B. henselae and R. typhi by indirect fluorescence antibody test. IgG against B. henselae and R. typhi were present in 17.8% (36/202) and 4.5% (9/202) of the participants, respectively; co-occurring IgG against both B. henselae and R. typhi were detected in 3.5% (7/202), whereas only anti-B. henselae IgG in 14.3% (29/202), and only anti-R. typhi IgG in 1.0% (2/202). Titres 1/64, 1/128, 1/256, and 1/512, of anti-B. henselae IgG were identified in 6.4%, 4.5%, 4.5%, and 2.4%, whereas titres 1/40 and 1/80 of anti-R. typhi IgG were detected in 4.0%, and 0.5%, respectively. A positive association of anti-B. henselae IgG prevalence with a coastal area featuring a major seaport (p = 0.009) and with younger age (p = 0.046) was identified. The findings of this survey raise concern for exposure of the population of Attica to B. henselae and R. typhi, which should be considered in the differential diagnosis when compatible symptoms are present. Our results also suggest that seaports may represent high-risk areas for exposure to Bartonella spp.