|
1
|
de Araújo FES, Martins TF, Ramos CCM, Nogueira RMS, Faccini JLH, Tavares MA, de Lima NJ, de Almeida Júnior EB, de Sousa-Paula LC, Dantas-Torres F, da Silva Krawczak F, Costa-Junior LM, Labruna MB, Dall Agnol LT, Luz HR. Seasonal dynamics of Amblyomma cajennense (Fabricius, 1787) sensu stricto in a degraded area of the Amazon biome, with notes on Rickettsia amblyommatis infection. Parasit Vectors 2023; 16:391. [PMID: 37891604 PMCID: PMC10612284 DOI: 10.1186/s13071-023-05978-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/23/2023] [Indexed: 10/29/2023] Open
Abstract
BACKGROUND The tick Amblyomma cajennense sensu stricto (A. cajennense s.s.) frequently parasitizes animals and humans in the Amazon biome, in addition to being a vector of Rickettsia amblyommatis. In the present study, we evaluated both the population dynamics of A. cajennense s.s. in a degraded area of the Amazon biome and the presence of rickettsial organisms in this tick population. METHODS The study was carried out in a rural area of the Santa Inês municipality (altitude: 24 m a.s.l.), Maranhão state, Brazil. Ticks were collected from the environment for 24 consecutive months, from June 2021 to May 2023. The region is characterized by two warm seasons: a rainy season (November-May) and a dry season (June-October). We characterized the temporal activity of A. cajennense s.s. on the vegetation by examining questing activity for each life stage (larvae, nymphs, adults [males and females]) in relation to the dry and rainy season. Ticks collected in this study were randomly selected and individually tested by a TaqMan real-time PCR assay that targeted a 147-bp fragment of the rickettsial gltA gene. RESULTS Overall, 1843 (62.4%) adults (52.6% females, 47.4% males), 1110 (37.6%) nymphs and 398 larval clusters were collected. All adult females and nymphs were morphologically identified as A. cajennense s.s. Larval activity was observed from April to December, with a peak from June to September (dry season); nymph abundance peaked from September to November (transition period between dry and rainy seasons); and adult ticks were abundant from October to May (spring/summer/early autumn). The infection rate by R. amblyommatis in A. cajennense s.s. ticks was at least 7% (7/99). CONCLUSION Our data suggest a 1-year generation pattern for A. cajennense s.s., with a well-defined seasonality of larvae, nymphs and adults in the Amazon biome. Larvae predominate during the dry season, nymphs are most abundant in the dry-rainy season transition and adults are most abundant in the rainy season. The presence of R. amblyommatis in adult ticks suggests that animals and humans in the study region are at risk of infection by this species belonging to the spotted fever group of Rickettsia.
Collapse
Affiliation(s)
| | - Thiago Fernandes Martins
- Pasteur Institute, São Paulo State Department of Health, São Paulo, SP, Brazil
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | | | - João Luiz Horacio Faccini
- Post-Graduation Program in Health Sciences, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | | | | | - Eduardo Bezerra de Almeida Júnior
- Post-Graduation Program in Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | - Lucas Christian de Sousa-Paula
- Tick-Pathogen Transmission Unit, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, Hamilton, MT, USA
| | - Filipe Dantas-Torres
- Department of Immunology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation (Fiocruz), Recife, PE, Brazil
| | | | - Livio Martins Costa-Junior
- Post-Graduation Program in Northeast Biotechnology Network (RENORBIO), Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil
| | - Marcelo Bahia Labruna
- Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil
| | | | - Hermes Ribeiro Luz
- Post-Graduation Program in Health and Environment, Federal University of Maranhão, São Luís, MA, Brazil.
- Post-Graduation Program in Northeast Biotechnology Network (RENORBIO), Biodiversity and Conservation, Center of Biological and Health Sciences, Federal University of Maranhão, São Luís, MA, Brazil.
| |
Collapse
|
|
2
|
Unpacking the intricacies of Rickettsia-vector interactions. Trends Parasitol 2021; 37:734-746. [PMID: 34162522 DOI: 10.1016/j.pt.2021.05.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/27/2021] [Accepted: 05/20/2021] [Indexed: 12/19/2022]
Abstract
Although Rickettsia species are molecularly detected among a wide range of arthropods, vector competence becomes an imperative aspect of understanding the ecoepidemiology of these vector-borne diseases. The synergy between vector homeostasis and rickettsial invasion, replication, and release initiated within hours (insects) and days (ticks) permits successful transmission of rickettsiae. Uncovering the molecular interplay between rickettsiae and their vectors necessitates examining the multifaceted nature of rickettsial virulence and vector infection tolerance. Here, we highlight the biological differences between tick- and insect-borne rickettsiae and the factors facilitating the incidence of rickettsioses. Untangling the complex relationship between rickettsial genetics, vector biology, and microbial interactions is crucial in understanding the intricate association between rickettsiae and their vectors.
Collapse
|