Rickettsia bellii, Rickettsia amblyommii, and Laguna Negra hantavirus in an Indian reserve in the Brazilian Amazon

Abstract

BackgroundThe purpose of this study was to identify the presence of rickettsia and hantavirus in wild rodents and arthropods in response to an outbreak of acute unidentified febrile illness among Indians in the Halataikwa Indian Reserve, northwest of the Mato Grosso state, in the Brazilian Amazon. Where previously surveillance data showed serologic evidence of rickettsia and hantavirus human infection.MethodsThe arthropods were collected from the healthy Indian population and by flagging vegetation in grassland or woodland along the peridomestic environment of the Indian reserve. Wild rodents were live-trapped in an area bordering the reserve limits, due the impossibility of capturing wild animals in the Indian reserve. The wild rodents were identified based on external and cranial morphology and karyotype. DNA was extracted from spleen or liver samples of rodents and from invertebrate (tick and louse) pools, and the molecular characterization of the rickettsia was through PCR and DNA sequencing of fragments of two rickettsial genes (gltA and ompA). In relation to hantavirus, rodent serum samples were serologically screened by IgG ELISA using the Araraquara-N antigen and total RNA was extracted from lung samples of IgG-positive rodents. The amplification of the complete S segment was performed.ResultsA total of 153 wild rodents, 121 louse, and 36 tick specimens were collected in 2010. Laguna Negra hantavirus was identified in Calomys callidus rodents and Rickettsia bellii, Rickettsia amblyommii were identified in Amblyomma cajennense ticks.ConclusionsZoonotic diseases such as HCPS and spotted fever rickettsiosis are a public health threat and should be considered in outbreaks and acute febrile illnesses among Indian populations. The presence of the genome of rickettsias and hantavirus in animals in this Indian reserve reinforces the need to include these infectious agents in outbreak investigations of febrile cases in Indian populations.

Ticks and tick-associated spotted fever group Rickettsia from birds in the southwestern Brazilian Amazon

“…A series of studies have put in evidence the occurrence of a great diversity of rickettsial agents infecting ticks hosted by different vertebrate groups (amphibians, reptiles, birds, and mammals) in the Amazon biome (Labruna et al, 2004a;Parola et al, 2007;Ogrzewalska et al, 2010;2012;De Barros-Lopes et al, 2014;Soares et al, 2015). Hence, knowledge of the diversity of ticks infesting Amazonian birds is of great public health concern because many of these birds have the potential to transport Rickettsia-infected ticks to other New World biomes, including into the Nearctic region (Mukherjee et al, 2014;Cohen et al, 2015).…”

Relative Sensitivity of Conventional and Real-Time PCR Assays for Detection of SFG Rickettsia in Blood and Tissue Samples from Laboratory Animals

“…Studies on the natural transmission cycles of zoonotic pathogens and the reservoir competence of vertebrate hosts require methods for reliable diagnosis of infection in wild and laboratory animals. A variety of PCR-based assays are now widely used for the detection of rickettsial DNA in animal tissues and blood samples [ 1 , 2 , 3 ]. However, molecular assays are not infallible as the quality of the extracted DNA and, consequently, the PCR results are affected by conditions of sample acquisition, storage, and transportation, as well as methods used for DNA preparation.…”

Epidemiology, Biodiversity, and Technological Trajectories in the Brazilian Amazon: From Malaria to COVID-19

“…Recently, the disease was described as being caused by Rickettsia typhi in the Amazon, transmitted to humans by fleas. In 2009, a rickettsiosis outbreak was investigated in an indigenous population in the state of Mato Grosso ( 67 ). Better tools for monitoring rickettsioses should, therefore, be a priority in the Amazon.…”