Historical overview and update on relapsing fever group Borrelia in Latin America.

Relapsing fever group Borrelia (RFGB) are motile spirochetes transmitted to mammalian or avian hosts through the bite of hematophagous arthropods, such as soft ticks (Argasidae), hard ticks (Ixodidae) and the human clothing lice. RFGB can infect pets such as dogs and cats, as well as birds, cattle and humans. Borrelia recurrentis, B. anserina and B. theileri are considered to have worldwide distribution, affecting humans, domestic birds and ruminants, respectively. Borrelia spp. associated with soft ticks are transmitted mainly by Ornithodoros ticks and thrive in endemic foci in tropical and subtropical latitudes. Nowadays, human cases of soft tick-borne relapsing fever remain neglected diseases in several countries, and the impact these spirochetes have on the health of wild and domestic animals is largely understudied. Human infection with RFGB is difficult to diagnose, given the lack of distinguishing clinical features (undifferentiated febrile illness). Clinically, soft tick or louse-borne relapsing fever is often confused with other etiologies, such as malaria, typhoid or dengue. In Latin America, during the first half of the twentieth century historical documents elaborated by enlightened physicians were seminal, and resulted in the identification of RFGB and their associated vectors in countries such as Mexico, Panama, Colombia, Venezuela, Peru and Argentina. Almost 80 years later, research on relapsing fever spirochetes is emerging once again in Latin America, with molecular characterizations and isolations of novel RFGB members in Panama, Bolivia, Brazil and Chile. In this review we summarize historical aspects of RFGB in Latin America and provide an update on the current scenario regarding these pathogens in the region. To accomplish this, we conducted an exhaustive search of all the published literature for the region, including old medical theses deposited in libraries of medical academies. RFGB were once common pathogens in Latin America, and although unnoticed for many years, they are currently the focus of interest among the scientific community. A One Health perspective should be adopted to tackle the diseases caused by RFGB, since these spirochetes have never disappeared and the maladies they cause may be confused with etiologies with similar symptoms that prevail in the region.

Tick-Borne Relapsing Fever in Southwest Colorado: A Case Report.

BACKGROUND: Tick-borne relapsing fever (TBRF) is a zoonosis caused by spirochetes of the genus Borrelia. The zoonosis is endemic in higher-elevation coniferous forests of the western United States. CASE REPORT: We discuss the case of a 44-year-old male residing in the San Juan Mountains of Western Colorado who presented with fever, myalgia, vomiting, and "violent chills" to an emergency department. Laboratory studies were notable for bandemia and thrombocytopenia with mild hyperbilirubinemia. Peripheral smear demonstrated multiple Borrelia spirochetes. The patient was treated with parenteral ceftriaxone and discharged with oral doxycycline therapy and recovered uneventfully. We discuss the clinical and epidemiological features of TBRF and the salient points for clinical diagnosis and management of this rare but important disease entity. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: TBRF is a rare and potentially life-threatening infectious process, which presents with nonspecific findings and often poses a diagnostic challenge. TBRF should be considered in the differential diagnosis for patients residing or vacationing in high-altitude forested areas in the western United States.

[A patient with fever following a visit to the tropics: tick-borne relapsing fever discovered in a thick blood smear preparation]. / Een patiënt met koorts na een bezoek aan de tropen: 'tick-borne relapsing fever' ontdekt in een dikkedruppelpreparaat.

A 26-year-old woman presented with a 2-day history of fever peaking to 39 degrees C and cold shivers that developed after a 2-weeks trip to Guatemala and Belize. Prior to the fever the patient had felt symptoms of a common cold and general malaise. Moreover, she complained of generalised myalgia and nausea. She had taken paludrine as a prophylactic against malaria. Borrelia spirochaetes, the pathogen of relapsing fever, were detected in a thick blood smear preparation. On the basis of the anamnesis, geography and specific exposure, the patient had a form of relapsing fever that is transmitted by ticks and not by lice: tick-borne relapsing fever. She was treated with doxycycline, 100 mg b.i.d. for 7 days. She could be discharged home in good condition after 2 days.

Dermatoses from ticks

Ticks are ectoparasites that cause dermatologic disease directly by their bite and indirectly as vectors of bacterial, rickettsial, protozoal, and viral diseases. In North America, where ticks are the leading cause of vector-borne infection, dermatologists should recognize several tick species. Basic tick biology and identification will be reviewed. Tick bites cause a variety of acute and chronic skin lesions. The tick-borne diseases include Lyme disease, tick-borne relapsing fever, tularemia, babesiosis, Rocky Mountain spotted fever, other spotted fevers, ehrlichiosis, Colorado tick fever, and others. The epidemiology, clinical features, diagnosis, and treatment of these diseases are reviewed with an emphasis on cutaneous manifestations. Finally, the prevention of diseases caused by ticks is reviewed.

Tickborne relapsing fever outbreak after a family gathering--New Mexico, August 2002.

On August 2, 2002, the New Mexico Department of Health (NMDOH) and the Indian Health Service (IHS) were notified of a tickborne relapsing fever (TBRF) outbreak after a 1-day family gathering held in late July at a remote, previously uninhabited cabin located in a mountainous region of northern New Mexico (elevation: approximately 8,000 feet). Approximately 40 persons attended the event; at least half slept overnight in the cabin. This report summarizes the investigation of this outbreak, which indicates that prompt diagnosis and collaboration among clinicians and public health authorities can reduce morbidity associated with TBRF. Persons living in areas where TBRF is endemic should avoid sleeping in rodent-infested buildings, rodent-proof susceptible buildings, and consider fumigation of buildings that harbor rodents.

El micrometodo de concentracion para diagnostico de la borreliosis / Concentration micromethod for the diagnosis of borreliosis

Las fiebres recurrentes son producidas por espiroquetas del genero Borrelia y transmitidas a otros por garrapatas y piojos. Nosotros hemos estudiado la sensibilidad y especificidad de un micrometodo de concentracion para el diagnostico de la Borreliosis en sangre. Se tomo sangre de ratones que fueron inoculados previamente con una cepa de Borrelia de origen humano. Tubos de micro-hematocrito fueron llenados con sangre, centrifugados y observados a traves del microscopio. La observacion se realiza en la interface de los globulos rojos y el plasma. El micrometodo se muestra mas sensible cuando los niveles de bacteremia son bajos