MAPPING ORIENTIA SPP. IN CHILE: DIVERSITY AND VECTOR ASSOCIATIONS

Isabella Pereira Pesenato; Ana Cláudia Calchi; RICARDO BASSINI SILVA; Adriana Santodomingo Santodomingo; Richard Thomas; Carolina Silva de la Fuente; Fernando de Castro Jacinavicius

Todos os Trabalhos

Trabalho

Título do Trabalho

MAPPING ORIENTIA SPP. IN CHILE: DIVERSITY AND VECTOR ASSOCIATIONS

Autores

Isabella Pereira Pesenato
Ana Cláudia Calchi
RICARDO BASSINI SILVA
Adriana Santodomingo Santodomingo
Richard Thomas
Carolina Silva de la Fuente
Fernando de Castro Jacinavicius

Modalidade

Resumo

Área temática

Protozoologia e patógenos transmitidos por vetores

Data de Publicação

24/09/2026

País da Publicação

Brasil

Idioma da Publicação

pt-BR

Página do Trabalho

https://www.even3.com.br/anais/23-congresso-brasileiro-de-parasitologia-veterinaria-673729/1561400-mapping-orientia-spp-in-chile--diversity-and-vector-associations

ISBN

978-65-272-2733-5

Palavras-Chave

Diversity, Taxonomy, Infectious diseases, Trombiculidae, Scrub typhus

Resumo

Chigger mites (Trombidiformes: Trombiculidae s.l.) have a cosmopolitan distribution and represent an important public health concern due to their ability to cause dermatitis and transmit microorganism. The larval stage parasitizes all terrestrial vertebrates, including humans, who serve as accidental hosts. For many years, the genus Orientia was considered monotypic, comprising only Orientia tsutsugamushi, and this distribution was thought to be restricted to the so-called “Tsutsugamushi Triangle.” This view was changed by reports of scrub typhus cases outside of this area, including the southern Chile, in Chiloé Island. Following these initial detections, it was assumed that Orientia circulation was restricted to the Chiloé region. Therefore, the objective of this study was to conduct a comprehensive Orientia surveillance in mites collected across the Chilean territory. Mite samples used in this study were collected from wild rodents across Chile, encompassing the Big North, Small North, Central, and Southern regions. The samples were processed either individually or in pools of up to 40 mites originating from the same host. DNA was extracted from absolute ethanol-preserved specimens using the DNeasy Blood & Tissue Kit (Qiagen). Conventional PCR assays targeting endogenous mite genes (18S rRNA and cox1) were first performed to assess sample viability. Samples that tested positive for one or both endogenous markers were considered viable and were subsequently screened by qPCR for bacteria of the genus Orientia, using genus-specific primers targeting the 16S rDNA gene. A total of 126 samples were evaluated, of which 75 were analyzed individually and 51 as mite pools. Voucher specimens were slide-mounted and morphologically identified as unidentified Carebareia Goff and Brennan; unidentified Morelacarus Vercammen-Grandjean; Paratrombicula chilensis Stekolnikov and González-Acuña; Quadraseta chiloensis Stekolnikov and Silva-de la Fuente; and unidentified Quadraseta Brennan. Among the tested samples, 19 were positive for Orientia. These detections originated from mites identified as Quadraseta sp. and Carebareia sp. Notably, this is the first report of Orientia DNA in a mite of the genus Carebareia. One of the positive samples corresponded to a protonymph originally collected as a larva in Cochamó, Los Lagos, and reared under laboratory conditions until the protonymph stage. This finding may indicate that chigger mites are capable of maintaining Orientia across transstadial developmental stages.

Título do Evento: 23º Congresso Brasileiro de Parasitologia Veterinária
Cidade do Evento: Belo Horizonte
Título dos Anais do Evento: Anais do XXIII Congresso Brasileiro de Parasitologia Veterinária
Nome da Editora: Even3
Meio de Divulgação: Meio Digital

Como citar

PESENATO, Isabella Pereira et al.. MAPPING ORIENTIA SPP. IN CHILE: DIVERSITY AND VECTOR ASSOCIATIONS.. In: Anais do XXIII Congresso Brasileiro de Parasitologia Veterinária. Anais...Belo Horizonte(MG) Centro de Atividades Didáticas I (CAD 1) da Universidade Federal de Minas Gerais (UFMG), 2026. Disponível em: https//www.even3.com.br/anais/23-congresso-brasileiro-de-parasitologia-veterinaria-673729/1561400-MAPPING-ORIENTIA-SPP-IN-CHILE--DIVERSITY-AND-VECTOR-ASSOCIATIONS. Acesso em: 01/11/2026