Occurrence of pathogenic fungi to Amblyomma cajennense in a rural area of Central Brazil and their activities against vectors of Rocky Mountain spotted fever.
Abstract: Two isolates of Beauveria bassiana and one of Purpureocillium lilacinum (=Paecilomyces lilacinus) were found infecting Amblyomma cajennense engorged females collected on horses (0.15% infection rate from a total of 1982 specimens) and another two isolates of P. lilacinum and one Metarhizium anisopliae detected in soils (2.1% from 144 samples) collected in typical pasture habitats of this tick in Central Brazil from October 2009 to March 2011. Fungi were isolated from soils with Rhipicephalus sanguineus as surrogate baits. No fungi were found in ticks or soils during the driest months (May to August). Testing pathogenicity of fungi all R. sanguineus females were killed regardless of the isolate and fungi sporulated abundantly on the cadavers. A. cajennense was less susceptible to infection with P. lilacinum within 20 days than R. sanguineus. All three fungal species probably act as natural antagonists of A. cajennense particularly in the rainy season and have interest for integrate control of vectors of Rocky Mountain spotted fever.
Copyright © 2012 Elsevier B.V. All rights reserved.
Publication Date: 2012-03-01 PubMed ID: 22459109DOI: 10.1016/j.vetpar.2012.02.016Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research investigates the occurrence and effects of certain types of fungi on a particular species of tick found in Central Brazil. These fungi could potentially be used to help control the species of ticks that transmit Rocky Mountain spotted fever.
Discovery of Pathogenic Fungi on Ticks
- The survey was conducted in a rural area in Central Brazil and focused on finding occurrences of fungi on a species of tick known as Amblyomma cajennense. This tick species is prevalent in the region and is a well-known vector of Rocky Mountain spotted fever.
- The researchers collected a total of 1982 engorged female ticks from horses. Out of these, 0.15% were found to be infected by two isolates of Beauveria bassiana and one isolate of Purpureocillium lilacinum.
- Apart from directly testing the ticks, the research team also collected soil samples from typical pasture habitats of A. cajennense. They found that 2.1% of the collected 144 samples carried two isolates of P. lilacinum and one isolate of Metarhizium anisopliae.
Testing of Fungi in Controlled Conditions
- Rhipicephalus sanguineus, another species of tick, was used as a surrogate bait for isolating the fungi from the collected soil samples.
- The researchers observed that no fungi were found in the ticks or soils during the driest months (from May to August), suggesting that these fungi thrive better in moist conditions.
- In controlled conditions, all tested R. sanguineus females were killed regardless of the type of fungal isolate, showing that these fungi are highly effective against ticks. Furthermore, the fungi sporulated abundantly on the cadavers, indicating a high potential for spreading.
- However, A. cajennense was found to be less susceptible to infection with P. lilacinum within 20 days than R. sanguineus. This could be a potential challenge if these fungi are used for controlling this tick species.
Implication of Findings
- Considering the high pathogenicity of the discovered fungi against ticks and their natural prevalence in the same habitats, these fungal species likely act as natural antagonists of A. cajennense, particularly in the rainy season.
- These findings are of great significance because they may provide a biological means to control the population of these ticks, thereby reducing the transmission of Rocky Mountain spotted fever.
Cite This Article
APA
D'Alessandro WB, Humber RA, Luz C.
(2012).
Occurrence of pathogenic fungi to Amblyomma cajennense in a rural area of Central Brazil and their activities against vectors of Rocky Mountain spotted fever.
Vet Parasitol, 188(1-2), 156-159.
https://doi.org/10.1016/j.vetpar.2012.02.016 Publication
Researcher Affiliations
- DMIPP, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil.
MeSH Terms
- Animals
- Beauveria / pathogenicity
- Beauveria / physiology
- Brazil / epidemiology
- Female
- Ixodidae / microbiology
- Paecilomyces / pathogenicity
- Paecilomyces / physiology
- Pest Control, Biological
- Rain
- Rocky Mountain Spotted Fever / transmission
- Seasons
- Soil Microbiology
Citations
This article has been cited 2 times.- Ribeiro-Silva CS, Muniz ER, Lima VH, Bernardo CC, Arruda W, Castro RN, Gôlo PS, Angelo IC, Fernandes ÉKK. Cuticular Lipids as a First Barrier Defending Ixodid Ticks against Fungal Infection.. J Fungi (Basel) 2022 Nov 8;8(11).
- Ren Q, Sun M, Guan G, Liu Z, Chen Z, Liu A, Li Y, Ma M, Yang J, Niu Q, Liu J, Han X, Yin H, Luo J. Susceptibility of the tick Haemaphysalis qinghaiensis to isolates of the fungus Metarhizium anisopliae in China.. Exp Appl Acarol 2014 Oct;64(2):253-8.
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