A fatal case series of Rocky Mountain spotted fever in Sonora, México

Abstract

-Hernández: concepción y diseño del estudio Todos los autores participaron en la recolección, análisis e interpretación de los datos, y en la redacción y revisión del manuscrito. Una serie de casos fatales de fiebre manchada de las Montañas Rocosas en Sonora, México Materials and methods:We conducted a cross-sectional study on a series of 47 deaths caused by Rickettsia rickettsii from 2013 to 2016. The diagnosis of Rocky Mountain spotted fever was confirmed in a single blood sample by polymerase chain reaction (PCR) or by a four-fold increase in immunoglobulin G measured in paired samples analyzed by indirect immunofluorescence. Clinical and laboratory characteristics were compared stratifying subjects into two groups: pediatric and adult.Results: There were no differences in clinical characteristics between groups; petechial rash was the most frequent sign (96%), followed by headache (70%) and myalgia (67%). Although that doxycycline was administered before the fifth day from the onset of symptoms, death occurred in 55% of patients. In clinical laboratory, thrombocytopenia, and biomarkers of liver acute failure and acute kidney failure were the most frequent. Conclusion: Rocky Mountain spotted fever remains as one of the most lethal infectious diseases, which may be related not only to the lack of diagnostic suspicion and delayed administration of doxycycline, 70Biomédica 2018;38:69-76 Delgado-De la Mora J, Licona-Enríquez JD, Leyva-Gastélum M, et al. but to genotypic characteristics of Rickettsia rickettsii that may play a role in the variability of the fatality rate that has been reported in other geographical regions where the disease is endemic.

Rocky Mountain Spotted Fever in a Large Metropolitan Center, Mexico–United States Border, 2009–2019

“…For these reasons, we compared PCR-positive cases to those with only a positive IFA result and identified substantial differences between these groups. The clinical characteristics of PCR-positive case-patients in Mexicali matched closely with those described for well-characterized series from Arizona, USA, and Coahuila and Sonora, Mexico ( 3 , 22 , 36 , 37 ). In contrast, case-patients with a single IgG titer were less likely to demonstrate many of the classical characteristics of RMSF, including rash, myalgia, abdominal pain, nausea, and vomiting.…”

Is Rocky Mountain spotted fever the only disease of the spotted fever group rickettsioses found in Mexico?

“…RMSF has been widely documented in the country. However, unlike the clinical characteristics reported in these publications (which are usually similar), national case fatality rates (CFRs) vary between 20.2% and 92% 1,3 , remaining high even when doxycycline is administered in the first 5 days of evolution 3 . Such differences are even more significant when compared to those published by the United States, where the CFR is < 1% 4 .…”

Discusión de factores pronóstico en dos casos familiares de fiebre manchada de las Montañas Rocosas

“…1,2 En la era pre-antibiótica (1909) se estimó una mortalidad de 65-90% en Estados Unidos 3 y de 77-91% en México.…”