Adela Oliva Chavez
she/her
Assistant Professor
Research interests: Extracellular vesicles, tick feeding, skin immune responses, epigenetics, tick management, diagnostics
740 Russell Labs
1630 Linden Dr.
Madison, WI 53706
Education
- Ph.D. University of Minnesota. Department of Entomology. Saint Paul, MN. (March 2008 – December 2013).
- M.Sc. University of Minnesota. Department of Entomology. Saint Paul, MN. (August 2005 – March 2008).
- B.Sc. Pan-American School of Agriculture “Zamorano”. Agricultural Engineer. Honduras. (January 2000 – December 2003)
Research Focus
Understanding the molecular and cellular interactions between ticks, their hosts, and the pathogens they transmit. Hard ticks, unlike other hematophagous arthropods, feed for long period of time (days to weeks). Thus, they have developed intricate mechanisms to manipulate their host immune and wound healing responses. This allows tick to feed uninterrupted and provides a safe haven to the pathogens they transmit. Using intracellular bacteria within the Anaplasmataceae family, we study the effect of tick-borne pathogen transmission in the skin responses and are characterizing how inflammatory and delayed wound healing aids in the establishment of infection in the skin. We utilize molecular, immunological, and microbiology techniques to define the role of extracellular vesicles in the modulation of host responses, how ticks regulate the content (proteins and miRNAs) within these extracellular, and what effect pathogens have on tick extracellular vesicle cargo.
Epigenetic drivers of tick adaptation and pathogen transmission. Tick-borne diseases are gaining relevance in the US. Interestingly, 80% of the cases are concentrated in the Northeastern and Midwestern, US. Several factors play a role in an arthropod’s ability to vector pathogens, which may impact pathogen distribution. Behavioral and biological differences between tick populations may be driven by epigenetics. Epigenetic variations correlate with global transcriptional changes that result in phenotypic plasticity. In bees, caste differentiation is influenced by variations in DNA methylation in response to environmental and nutritional clues. We will investigate the role of epigenetics in tick biology by looking at the methylation of Ixodes scapularis DNA to determine epigenetic variations between tick populations in the South (Texas), Midwest (Minnesota), and Northeast (Pennsylvania), US. By establishing the link between epigenetics and vector competence, we can develop novel approaches to reduce the capacity of ticks to vector pathogens.
Development of novel tick management strategies. Ticks and tick-borne disease significantly affect livestock worldwide. Tick feeding can reduce milk production, reduced weight gain, damage to hides, anemia, and even death. Current tick control measures are focused on the use of synthetic acaricides. Nevertheless, the emergence of resistance to several acaricides in tick populations has become a source of concern. Thus, increased interest has emerged in finding alternative approaches for the control of tick populations. One of such approaches is the development of anti-tick vaccines. Although some subunit vaccines have shown partial protection, polymorphism in protein sequence between tick populations and tick species reduces their efficiency. This project aims to examine the potential use of tick salivary glands- and midgut-derived extracellular vesicles as vaccine candidates against ticks. Effective tick vaccines will decrease the impact that ticks have on cattle and lessen the tick-borne disease burden. This knowledge can then be applied to other systems, potentially impacting animal and human health.
Tick-borne disease biomarker identification for diagnostics. Tick-borne diseases are the most significant vector-borne diseases in the U.S. Lyme disease alone affects around 400,000 people per year according to insurance estimates. Although serological and molecular diagnostics, such as ELISA and PCR, are used in clinical settings, these techniques sometimes result in undesirable rates of false negatives or false positives. This is particularly true during the early phases of infection, when pathogen numbers are low and pathogen-specific antibodies have not been mounted or antibodies mounted cross-react with antigens present in other tick-borne pathogens. We are characterizing the content of circulating extracellular vesicles to identify potential biomarkers that can be exploited for the development of new diagnostic approaches.
These novel techniques will potentially permit the early accurate diagnosis of these illnesses and coinfections with tick-borne pathogens to allow for prompt treatment.
About Me
I am a 6-time marathon runner, scuba diver, and cat enthusiast
Publications
Online Profiles
Recent Publications
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Scientific reports. pmid:42092101, pmc:PMC13333938, doi:10.1038/s41598-026-51703-8
Hard ticks are a source of public health concern, in part due to their ability to inhabit different environments. In the United States (US), blacklegged ticks (Ixodes scapularis Say), the primary vector of Lyme disease, exhibit various phenotypes depending on their geographic origin (i.e. northern and southern US ticks). Although genetics may partially explain how blacklegged tick populations acclimate to different environmental conditions across the US, epigenetics may also contribute to their…
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Medical and veterinary entomology. pmid:41964202, doi:10.1111/mve.70072
Amblyomma spp. (Acari, Ixodidae) serve as primary vectors for numerous pathogens affecting humans and animals. Unlike other arthropods, ixodid ticks exhibit notably less susceptibility to entomopathogenic fungi, which are widely used as biological control agents. This study aimed to determine whether the dynamics of the cellular immune response to fungal infection differ between Amblyomma sculptum and Amblyomma americanum. Engorged female ticks were treated with conidial suspensions of…
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The Journal of investigative dermatology. pmid:40915408, pmc:PMC12603915, doi:10.1016/j.jid.2025.08.037
Wound healing has been extensively studied through the lens of inflammatory disorders and cancer, but limited attention has been given to hematophagy and arthropod-borne diseases. Hematophagous ectoparasites, including ticks, subvert the wound healing response to maintain prolonged attachment and facilitate blood feeding. In this study, we unveil a strategy through which extracellular vesicles ensure blood feeding and arthropod survival in 3 medically relevant tick species. Through single-cell…
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Vaccines. pmid:40333200, pmc:PMC12031118, doi:10.3390/vaccines13040355
CONCLUSIONS: Proteins within tick salivary and midgut vesicles are recognized by antibodies from vaccinated white-tailed deer. These proteins can be further evaluated for their function and potential as vaccine candidates against ticks.
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Ecology and evolution. pmid:39944902, pmc:PMC11814477, doi:10.1002/ece3.70987
Ticks and tick-borne pathogens represent the greatest vector-borne disease threat in the United States. Blacklegged ticks are responsible for most human cases, yet the disease burden is unevenly distributed across the northern and southern United States. Understanding the genetic characteristics influencing phenotypic differences in tick vectors is critical to elucidating disparities in tick-borne pathogen transmission dynamics. Applying evolutionary analyses to molecular variation in natural…
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Ticks and tick-borne diseases. pmid:39667072, doi:10.1016/j.ttbdis.2024.102420
Current tick control measures are focused on the use of synthetic acaricides and personal protective measures. However, the emergence of acaricide resistance and the maintenance of tick populations in wildlife has precluded the efficient management of ticks. Thus, host-targeted, non-chemical control measures are needed to reliably reduce ticks parasitizing sylvatic reservoirs. This project aimed to evaluate extracellular vesicles (EVs) from Amblyomma americanum as vaccine candidates for…
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Frontiers in cell and developmental biology. pmid:39376631, pmc:PMC11456543, doi:10.3389/fcell.2024.1460705
Ticks are important blood feeding ectoparasites that transmit pathogens to wildlife, domestic animals, and humans. Hard ticks can feed for several days to weeks, nevertheless they often go undetected. This phenomenon can be explained by a tick’s ability to release analgesics, immunosuppressives, anticoagulants, and vasodilators within their saliva. Several studies have identified extracellular vesicles (EVs) as carriers of some of these effector molecules. Further, EVs, and their contents,…
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bioRxiv : the preprint server for biology. pmid:37986907, pmc:PMC10659423, doi:10.1101/2023.11.10.566612
Wound healing has been extensively studied through the lens of inflammatory disorders and cancer, but limited attention has been given to hematophagy and arthropod-borne diseases. Hematophagous ectoparasites, including ticks, subvert the wound healing response to maintain prolonged attachment and facilitate blood-feeding. Here, we unveil a strategy by which extracellular vesicles (EVs) ensure blood-feeding and arthropod survival in three medically relevant tick species. Through single cell RNA…
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bioRxiv : the preprint server for biology. pmid:37961338, pmc:PMC10635084, doi:10.1101/2023.11.02.565357
CONCLUSIONS: Rab27 is needed for successful tick feeding and may be important for acquiring A. phagocytophilum during a blood meal. Additionally, silencing rab27 in tick cells results in a shift of extracellular vesicle size. Overall, we have observed that Rab27 plays a key role in tick EV biogenesis and the tripartite interactions among the vector, the mammalian host, and a microbe it encounters.
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Trends in parasitology. pmid:37591719, pmc:PMC10528898, doi:10.1016/j.pt.2023.07.009
Ticks can transmit a variety of human pathogens, including intracellular and extracellular bacteria, viruses, and protozoan parasites. Historically, their saliva has been of immense interest due to its anticoagulant, anti-inflammatory, and anesthetic properties. Only recently, it was discovered that tick saliva contains extracellular vesicles (EVs). Briefly, it has been observed that proteins associated with EVs are important for multiple tick-borne intracellular microbial lifestyles. The impact…
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Experimental & applied acarology. pmid:37052726, pmc:PMC10167096, doi:10.1007/s10493-023-00780-9
The cattle fever tick, Rhipicephalus (Boophilus) microplus, is the most economically important tick worldwide. Infestations with this tick can lead to direct damage and cattle mortality due to the transmission of potentially deadly pathogens. Management of this tick species has been focused on the use of synthetical acaricides; however, the emergence of acaricide resistance to single or multiple active ingredients has resulted in a need for novel acaricide compounds. Among potential avenues for…
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PloS one. pmid:36800354, pmc:PMC9937504, doi:10.1371/journal.pone.0266234
Ehrlichia ruminantium is a tick-borne intracellular pathogen of ruminants that causes heartwater, a disease present in Sub-saharan Africa, islands in the Indian Ocean and the Caribbean, inducing significant economic losses. At present, three avirulent strains of E. ruminantium (Gardel, Welgevonden and Senegal isolates) have been produced by a process of serial passaging in mammalian cells in vitro, but unfortunately their use as vaccines do not offer a large range of protection against other…
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Life (Basel, Switzerland). pmid:36556330, pmc:PMC9781593, doi:10.3390/life12121965
Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (HGA), is an obligate intracellular bacterium transmitted by the bite of black-legged ticks, Ixodes scapularis. The main host cells in vertebrates are neutrophils. However, the first site of entry is in the skin during tick feeding. Given that the initial responses within skin are a crucial determinant of disease outcome in vector-borne diseases, we used a non-biased approach to characterize the transcriptional…
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Journal of visualized experiments : JoVE. pmid:35467650, doi:10.3791/63618
Ticks are important ectoparasites that can vector multiple pathogens. The salivary glands of ticks are essential for feeding as their saliva contains many effectors with pharmaceutical properties that can diminish host immune responses and enhance pathogen transmission. One group of such effectors are microRNAs (miRNAs). miRNAs are short non-coding sequences that regulate host gene expression at the tick-host interface and within the organs of the tick. These small RNAs are transported in the…
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International journal of environmental research and public health. pmid:35162074, pmc:PMC8834366, doi:10.3390/ijerph19031051
The specific interactions of members of tick bacterial microbiota and their effects on pathogen transmission remains relatively unexplored. Here, we introduced a novel Wolbachia infection type into Ixodes scapularis tick cells and examined the antipathogenic effects on the intracellular pathogen Anaplasma phagocytophilum. An increase in A. phagocytophilum replication was observed in Wolbachia-infected tick cells. However, Wolbachia infection densities decreased when cells were serially passaged…
Selected Publications
- Butler LR, Gonzalez J, Pedra JHF, Oliva Chavez AS. Tick extracellular vesicles in host skin immunity and pathogen transmission. Trends Parasitol. 2023 Oct;39(10):873-885. doi: 10.1016/j.pt.2023.07.009. Epub 2023 Aug 16. Review. PubMed PMID: 37591719.
- Oliva Chávez AS, Guzman Valencia S, Lynn GE, Rosario CA, Thomas DB, Johnson TL. Evaluation of the in vitro acaricidal effect of five organic compounds on the cattle fever tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae). Exp Appl Acarol. 2023 Apr;89(3-4):447-460. doi: 10.1007/s10493-023-00780-9. Epub 2023 Apr 13. PubMed PMID: 37052726; PubMed Central PMCID: PMC10167096.
- Gordon JL, Oliva Chavez AS, Martinez D, Vachiery N, Meyer DF. Possible biased virulence attenuation in the Senegal strain of Ehrlichia ruminantium by ntrX gene conversion from an inverted segmental duplication. PLoS One. 2023;18(2):e0266234. doi: 10.1371/journal.pone.0266234. eCollection 2023. PubMed PMID: 36800354; PubMed Central PMCID: PMC9937504.
- Underwood J, Harvey C, Lohstroh E, Pierce B, Chambers C, Guzman Valencia S, Oliva Chávez AS. Anaplasma phagocytophilum Transmission Activates Immune Pathways While Repressing Wound Healing in the Skin. Life (Basel). 2022 Nov 24;12(12). doi: 10.3390/life12121965. PubMed PMID: 36556330; PubMed Central PMCID: PMC9781593.
- Leal-Galvan B, Harvey C, Thomas D, Saelao P, Oliva Chavez AS. Isolation of microRNAs from Tick Ex Vivo Salivary Gland Cultures and Extracellular Vesicles. J Vis Exp. 2022 Apr 6;(182). doi: 10.3791/63618. PubMed PMID: 35467650.
- Skinner KM, Underwood J, Ghosh A, Oliva Chavez AS, Brelsfoard CL. Wolbachia Impacts Anaplasma Infection in Ixodes scapularis Tick Cells. Int J Environ Res Public Health. 2022 Jan 18;19(3). doi: 10.3390/ijerph19031051. PubMed PMID: 35162074; PubMed Central PMCID: PMC8834366.
- Park JM, Oliva Chávez AS, Shaw DK. Ticks: More Than Just a Pathogen Delivery Service. Front Cell Infect Microbiol. 2021;11:739419. doi: 10.3389/fcimb.2021.739419. eCollection 2021. PubMed PMID: 34540723; PubMed Central PMCID: PMC8440996.
- Oliva Chávez AS, Wang X, Marnin L, Archer NK, Hammond HL, Carroll EEM, Shaw DK, Tully BG, Buskirk AD, Ford SL, Butler LR, Shahi P, Morozova K, Clement CC, Lawres L, Neal AJO, Mamoun CB, Mason KL, Hobbs BE, Scoles GA, Barry EM, Sonenshine DE, Pal U, Valenzuela JG, Sztein MB, Pasetti MF, Levin ML, Kotsyfakis M, Jay SM, Huntley JF, Miller LS, Santambrogio L, Pedra JHF. Tick extracellular vesicles enable arthropod feeding and promote distinct outcomes of bacterial infection. Nat Commun. 2021 Jun 17;12(1):3696. doi: 10.1038/s41467-021-23900-8. PubMed PMID: 34140472; PubMed Central PMCID: PMC8211691.
- Ante VM, Farris LC, Saputra EP, Hall AJ, O’Bier NS, Oliva Chávez AS, Marconi RT, Lybecker MC, Hyde JA. The Borrelia burgdorferi Adenylate Cyclase, CyaB, Is Important for Virulence Factor Production and Mammalian Infection. Front Microbiol. 2021;12:676192. doi: 10.3389/fmicb.2021.676192. eCollection 2021. PubMed PMID: 34113333; PubMed Central PMCID: PMC8186283.
- Pham M, Underwood J, Oliva Chávez AS. Changing the Recipe: Pathogen Directed Changes in Tick Saliva Components. Int J Environ Res Public Health. 2021 Feb 12;18(4). doi: 10.3390/ijerph18041806. Review. PubMed PMID: 33673273; PubMed Central PMCID: PMC7918122.
- Quadros DG, Johnson TL, Whitney TR, Oliver JD, Oliva Chávez AS. Plant-Derived Natural Compounds for Tick Pest Control in Livestock and Wildlife: Pragmatism or Utopia?. Insects. 2020 Aug 1;11(8). doi: 10.3390/insects11080490. Review. PubMed PMID: 32752256; PubMed Central PMCID: PMC7469192.
- Chávez ASO, O’Neal AJ, Santambrogio L, Kotsyfakis M, Pedra JHF. Message in a vesicle – trans-kingdom intercommunication at the vector-host interface. J Cell Sci. 2019 Mar 18;132(6). doi: 10.1242/jcs.224212. Review. PubMed PMID: 30886004; PubMed Central PMCID: PMC6451414.
- Oliva Chávez AS, Herron MJ, Nelson CM, Felsheim RF, Oliver JD, Burkhardt NY, Kurtti TJ, Munderloh UG. Mutational analysis of gene function in the Anaplasmataceae: Challenges and perspectives. Ticks Tick Borne Dis. 2019 Feb;10(2):482-494. doi: 10.1016/j.ttbdis.2018.11.006. Epub 2018 Nov 15. PubMed PMID: 30466964; PubMed Central PMCID: PMC6342664.
- McClure Carroll EE, Wang X, Shaw DK, O’Neal AJ, Oliva Chávez AS, Brown LJ, Boradia VM, Hammond HL, Pedra JHF. p47 licenses activation of the immune deficiency pathway in the tick Ixodes scapularis. Proc Natl Acad Sci U S A. 2019 Jan 2;116(1):205-210. doi: 10.1073/pnas.1808905116. Epub 2018 Dec 17. PubMed PMID: 30559180; PubMed Central PMCID: PMC6320499.
- McClure EE, Chávez ASO, Shaw DK, Carlyon JA, Ganta RR, Noh SM, Wood DO, Bavoil PM, Brayton KA, Martinez JJ, McBride JW, Valdivia RH, Munderloh UG, Pedra JHF. Engineering of obligate intracellular bacteria: progress, challenges and paradigms. Nat Rev Microbiol. 2017 Sep;15(9):544-558. doi: 10.1038/nrmicro.2017.59. Epub 2017 Jun 19. Review. PubMed PMID: 28626230; PubMed Central PMCID: PMC5557331.
- Oliva Chávez AS, Shaw DK, Munderloh UG, Pedra JH. Tick Humoral Responses: Marching to the Beat of a Different Drummer. Front Microbiol. 2017;8:223. doi: 10.3389/fmicb.2017.00223. eCollection 2017. Review. PubMed PMID: 28261180; PubMed Central PMCID: PMC5306392.
- Shaw DK, Wang X, Brown LJ, Chávez AS, Reif KE, Smith AA, Scott AJ, McClure EE, Boradia VM, Hammond HL, Sundberg EJ, Snyder GA, Liu L, DePonte K, Villar M, Ueti MW, de la Fuente J, Ernst RK, Pal U, Fikrig E, Pedra JH. Infection-derived lipids elicit an immune deficiency circuit in arthropods. Nat Commun. 2017 Feb 14;8:14401. doi: 10.1038/ncomms14401. PubMed PMID: 28195158; PubMed Central PMCID: PMC5316886.
- Oliva Chávez AS, Fairman JW, Felsheim RF, Nelson CM, Herron MJ, Higgins L, Burkhardt NY, Oliver JD, Markowski TW, Kurtti TJ, Edwards TE, Munderloh UG. An O-Methyltransferase Is Required for Infection of Tick Cells by Anaplasma phagocytophilum. PLoS Pathog. 2015;11(11):e1005248. doi: 10.1371/journal.ppat.1005248. eCollection 2015. PubMed PMID: 26544981; PubMed Central PMCID: PMC4636158.
- Oliver JD, Chávez AS, Felsheim RF, Kurtti TJ, Munderloh UG. An Ixodes scapularis cell line with a predominantly neuron-like phenotype. Exp Appl Acarol. 2015 Jul;66(3):427-42. doi: 10.1007/s10493-015-9908-1. Epub 2015 Apr 17. PubMed PMID: 25894426; PubMed Central PMCID: PMC4449809.
- Chávez AS, Felsheim RF, Kurtti TJ, Ku PS, Brayton KA, Munderloh UG. Expression patterns of Anaplasma marginale Msp2 variants change in response to growth in cattle, and tick cells versus mammalian cells. PLoS One. 2012;7(4):e36012. doi: 10.1371/journal.pone.0036012. Epub 2012 Apr 25. PubMed PMID: 22558307; PubMed Central PMCID: PMC3338850.
- Felsheim RF, Chávez AS, Palmer GH, Crosby L, Barbet AF, Kurtti TJ, Munderloh UG. Transformation of Anaplasma marginale. Vet Parasitol. 2010 Feb 10;167(2-4):167-74. doi: 10.1016/j.vetpar.2009.09.018. Epub 2009 Sep 20. PubMed PMID: 19837516; PubMed Central PMCID: PMC2817780.
- Baldridge GD, Burkhardt NY, Oliva AS, Kurtti TJ, Munderloh UG. Rickettsial ompB promoter regulated expression of GFPuv in transformed Rickettsia montanensis. PLoS One. 2010 Jan 29;5(1):e8965. doi: 10.1371/journal.pone.0008965. PubMed PMID: 20126457; PubMed Central PMCID: PMC2813287.
- Nelson CM, Herron MJ, Felsheim RF, Schloeder BR, Grindle SM, Chavez AO, Kurtti TJ, Munderloh UG. Whole genome transcription profiling of Anaplasma phagocytophilum in human and tick host cells by tiling array analysis. BMC Genomics. 2008 Jul 31;9:364. doi: 10.1186/1471-2164-9-364. PubMed PMID: 18671858; PubMed Central PMCID: PMC2527338.
- Baldridge GD, Kurtti TJ, Burkhardt N, Baldridge AS, Nelson CM, Oliva AS, Munderloh UG. Infection of Ixodes scapularis ticks with Rickettsia monacensis expressing green fluorescent protein: a model system. J Invertebr Pathol. 2007 Mar;94(3):163-74. doi: 10.1016/j.jip.2006.10.003. Epub 2006 Nov 27. PubMed PMID: 17125789; PubMed Central PMCID: PMC1868488.
Teaching
- Medical Entomology
- One-Health Entomology
Honors and Awards
- College of Agriculture and Life Sciences Dean’s Outstanding Achievement Award for Early Career Research. Texas A&M University. 2023
- USDA E. Kika De La Garza Science Fellow. USDA. 2023.
- Scialog Fellow: Mitigating Zoonotic Threats (MZT). Research Corporation for Science Advancement. 2021-2022.
- Young Scientist Ticks & Tick-borne Pathogens Award. International Ticks & Tick-borne Pathogens Meeting. 2014.
- Most Valuable PhD Student. Department of Entomology. University of Minnesota. 2009.
- Distinguished Master Thesis. Graduate School. University of Minnesota. 2009.
Professional Affiliations
- Frontiers in Cellular and Infection Microbiology – Veterinary and Zoonotic Infection, Associate Editor (2023-present)
- American Society for Rickettsiology, Diversity Ambassador (2022-present)
- Frontiers in Cellular and Infection Microbiology, Guest Editor (2021-2023)
- Zoonoses and public health, Editorial Board (2020-present)
- International journal of Environmental Research and Public Health, Guest Editor and Topics Board (2020-2023)