Fatal Rocky Mountain Spotted Fever along the United States-Mexico Border, 2013-2016

Abstract

Rocky Mountain spotted fever (RMSF) is an emerging public health concern near the US-Mexico border, where it has resulted in thousands of cases and hundreds of deaths in the past decade. We identified 4 patients who had acquired RMSF in northern Mexico and subsequently died at US healthcare facilities. Two patients sought care in Mexico before being admitted to US-based hospitals. All patients initially had several nonspecific signs and symptoms, including fever, headache, nausea, vomiting, or myalgia, but deteriorated rapidly without receipt of a tetracycline-class antimicrobial drug. Each patient experienced respiratory failure late in illness. Although transborder cases are not common, early recognition and prompt initiation of appropriate treatment are vital for averting severe illness and death. Clinicians on both sides of the US-Mexico border should consider a diagnosis of RMSF for patients with rapidly progressing febrile illness and recent exposure in northern Mexico.

Keywords: Arizona; California; Mexico; Rickettsia rickettsii; Rocky Mountain spotted fever; US–Mexico border; United States; rickettsia; tickborne disease; vector-borne infections; vectorborne infections.

Figure

Histologic slides of autopsy tissue from patients who acquired Rocky Mountain spotted fever in northern Mexico and died at hospitals in the United States, 2013–2016. A) Immunohistochemical stain of Rickettsia rickettsii antigens (red) in inflamed blood vessel adjacent to eccrine gland in a skin biopsy specimen from case-patient 1. Immunoalkaline phosphatase with naphthol-fast red and hematoxylin counterstain; original magnification ×50. B) Diffuse pulmonary capillaritis in case-patient 4. Hematoxylin and eosin stain; original magnification ×50. C) Vasculitis involving a small blood vessel in a peripheral nerve of case-patient 4. Hematoxylin and eosin stain; original magnification ×100.