Rickettsial Disease in the Peruvian Amazon Basin.

Area of Science:

• * Infectious Diseases
• * Medical Entomology
• * Zoonotic Pathogens

Background:

• * Rickettsial infections, including spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR), are significant public health concerns globally.
• * Undifferentiated febrile illnesses in endemic regions often require etiological diagnosis to guide treatment and surveillance.
• * The Peruvian Amazon is a region with potential for emerging infectious diseases due to its rich biodiversity and human-animal interactions.

Purpose of the Study:

• * To determine the prevalence of rickettsial infections in undifferentiated febrile cases in Iquitos, Peru.
• * To investigate the presence and transmission of spotted fever group rickettsiae (SFGR) and typhus group rickettsiae (TGR) in domestic animals and their ectoparasites.
• * To identify risk factors associated with rickettsial infections in the study population.

Main Methods:

• * A passive, clinic-based surveillance program enrolled 2,054 participants with undifferentiated febrile illness.
• * Blood samples from humans and animals were tested for SFGR and TGR using ELISA and PCR.
• * Ectoparasites (fleas and ticks) were collected from animals and screened for Rickettsia spp. by PCR. Logistic regression was used for statistical analysis.

Main Results:

• * Nearly 2% of human participants showed serological evidence of rickettsial infection.
• * Rickettsia spp. were detected in a high proportion of fleas (97.4%) and ticks (5%).
• * Candidatus Rickettsia asemboensis was identified in 100% of fleas and 33% of ticks, indicating pathogen presence in the local ectoparasite fauna.

Conclusions:

• * Human pathogenic SFGR are circulating in the Peruvian Amazon.
• * Domestic animals and their ectoparasites serve as reservoirs and vectors for rickettsial pathogens.
• * Individuals exposed to domestic and peri-domestic animals and their ectoparasites face a significant risk of rickettsial infection.