# Spotted Fever Rickettsioses in Panama: New Cases and the Gaps That Hinder Its Epidemiological Understanding

## TL;DR

This paper reports new cases of spotted fever rickettsiosis in Panama and highlights diagnostic and epidemiological challenges in understanding the disease's spread.

## Contribution

The study presents new clinical cases and identifies gaps in diagnosing and understanding the epidemiology of spotted fever rickettsioses in Panama.

## Key findings

- Fatal RRSF case in Coclé province and severe SFGR case in GBIC were confirmed through molecular and immunofluorescence methods.
- Coclé and GBIC are identified as key endemic areas for RRSF in Panama.
- Contact with ticks in various environments is linked to recent RRSF cases, highlighting the need for improved diagnostic suspicion.

## Abstract

Rickettsia rickettsii is the most virulent agent of the genus Rickettsia that causes one of the most relevant vector-borne diseases in the Americas (RRSF). RRSF manifests with many non-specific acute clinical symptoms complicating its diagnosis and can lead to death if not treated appropriately. RRSF has been reported in Canada, the United States of America, Mexico, Costa Rica, Panama, Colombia, Brazil, and Argentina. In addition to R. rickettsii, mild and severe spotted fever group rickettsioses (SFGR) have been reported in the Americas; however, the true prevalence of these diseases is unknown. In Panama, RRSF have been reported in four of 14 provinces during two outbreak periods: five cases including two fatalities were identified in 1950–1951, and 23 cases including 17 fatalities between 2004 and 2025. This paper presents the clinical characterization of a fatal case of RRSF in Coclé province and a severe case of SFGR in a mountainous area of the Gnäbe Buglé Indigenous Comarca (GBIC). Laboratory confirmation was performed by molecular analysis of tissues obtained from necropsies in the case of RRSF and by immunofluorescence assay (IFA) in the case of SFGR. Furthermore, this paper identifies existing gaps in the initial clinical suspicion and pertinent to SFGR in Panama, which may be applicable to other countries in the region. In the last 21 years, cases have occurred upon contact with ticks in rural areas (13), urban and suburban locations (7), rural woodlands (2), and forests (1). Provinces with more cases are Panamá (7 of 23, 6 died), Coclé (5 of 23, 5 died), Colón (3 of 23, 1 died), Panamá Oeste (1 of 23, 1 died), and GBIC (7 of 23, 4 died), including a cluster of seven cases in 2019. Therefore, Coclé province is considered one of the endemic areas for RRSF in Panama, while the latest cases from the GBIC since 2019 indicate that mountainous areas are an eco-epidemiological scenario to include in the transmission of these diseases. Although this disease has a low prevalence, patients who present symptoms commonly associated with more common diseases such as dengue, other arboviruses, malaria, and leptospirosis, among others, should be included in the diagnostic suspicion. Without diagnostic suspicion and adequate treatment, the patient can die.