About

Benjamin Cull is a Research Assistant Professor in the Department of Entomology at the University of Minnesota, joined the department in 2019. His research interests encompass a broad range of aspects related to vector-borne diseases, with a particular focus on ticks and tick-borne diseases. His work includes studying the biology and ecology of ticks and mosquitoes, vector and vector-borne pathogen surveillance, and host-pathogen-vector interactions. Dr. Cull is experienced in sampling blood-feeding arthropods of medical and veterinary concern, utilizing molecular techniques for pathogen detection and characterization, and employing in vitro cell culture techniques to examine tick-pathogen interactions. He also applies community science methods for collecting data on arthropod vectors. Prior to his current position, Dr. Cull worked in the Medical Entomology and Zoonoses Ecology team at the UK Health Security Agency, where he managed national surveillance projects for ticks and mosquitoes. His recent research involves using the open access citizen science platform iNaturalist to gather data on the distribution and species diversity of important tick and mosquito vector species. His current projects include investigating the endosymbiont Rickettsia buchneri in Ixodes scapularis and its role in shaping the tick's capacity to host other pathogens, studying the innate immune response of ticks to pathogens, developing new methods for tick and tick-borne pathogen surveillance, and updating information on Minnesota's tick biodiversity. Through combining molecular, cell biology, and ecological approaches, Dr. Cull aims to translate molecular findings into broader understanding of vector-borne disease eco-epidemiology.

Research topics

• Biology
• Ecology
• Medicine
• Virology
• Genetics
• Geography
• Veterinary medicine
• Zoology

Selected publications

• Eco-epidemiology of hard tick-borne rickettsiae in North America: A scoping review

  Open MIND · 2026-01-01

  otherOpen access1st authorCorresponding

  Objectives: To provide an overview of the distribution, eco-epidemiology, pathogenicity, and known/potential tick vectors and wildlife reservoirs of Rickettsia species associated with ticks in North America. Identify knowledge gaps in our understanding of these tick-borne Rickettsia.

  PublisherDOI

• <i>Rickettsia parkeri</i> hypothetical protein RPATATE_1266, a homolog of exopolyphosphatase/guanosine pentaphosphate phosphohydrolase, regulates tick cell apoptosis

  Microbiology Spectrum · 2025-07-07 · 1 citations

  articleOpen access

  ABSTRACT Rickettsia parkeri, an intracellular bacterium transmitted by Amblyomma maculatum ticks, causes a febrile illness associated with eschar formation in humans. As a less virulent member of the spotted fever group within the Rickettsia genus, R. parkeri serves as an ideal model for studying interactions between rickettsial pathogens, their vectors, and hosts. Our previous research showed that R. parkeri modulates mitochondrial-dependent apoptosis in tick cells, enhancing its intracellular survival and replication; however, the underlying mechanisms remain unclear. To investigate further, we employed a Himar1-based transposon mutagenesis system to identify R. parkeri genes involved in apoptosis. Using the modified plasmid pLoxHimar, we introduced a transposon into the R. parkeri Tate’s Hell strain and selected a mutant with an insertion in RPATATE_1266, a hypothetical protein with homology to exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (Ppx/Gppa) family proteins, using mCherry fluorescence and spectinomycin/streptomycin resistance. The mutant genotype and single insertion site were confirmed by insertion site sequencing and inverse PCR. We found that the RPATATE_1266 mutant had reduced infection rates, growth, and plaque formation compared to wild-type R. parkeri in tick and mammalian cells. Moreover, the mutant showed upregulation of genes associated with ppx/gppa gene regulation networks (GRNs) and exhibited a marked inhibition of apoptosis in tick cells, including decreased expression of apoptosis-related genes, reduced mitochondrial membrane potential, and less DNA fragmentation. Restoration of RPATATE_1266 resulted in significant recovery of later-phase apoptosis, as measured by Caspase 3/7 activity. These findings suggest that RPATATE_1266 is a critical regulator of apoptosis in tick cells and could be a potential target for controlling R. parkeri infection and replication. This research enhances our understanding of how vector responses to pathogen infection influence pathogen replication and transmission. IMPORTANCE Rickettsia parkeri infections, though less severe than other rickettsioses, are becoming increasingly significant due to the expanding geographic range of their tick vector and their role in shaping our understanding of rickettsial biology. Advancing knowledge of the molecular mechanisms that regulate R. parkeri infection and replication is important for the field of vector-pathogen interactions. This study identifies the RPATATE_1266 gene (a hypothetical protein with homology to exopolyphosphatase/guanosine pentaphosphate phosphohydrolase [Ppx/Gppa] family proteins) as a key regulator of mitochondrial-dependent apoptosis in tick cells, a process critical for rickettsial intracellular survival. By elucidating the role of this gene, we provide new insights into the molecular interactions between rickettsial pathogens and their vectors. These findings not only enhance our understanding of pathogen-vector dynamics but also highlight potential directions for developing future strategies to manage rickettsial diseases beyond those caused by R. parkeri.

  PublisherDOI

• Online Crowdsourced Data from iNaturalist Can Assist Monitoring of Invasive Mosquitoes

  Insects · 2025-01-28 · 3 citations

  articleOpen access1st authorCorresponding

  Invasive mosquitoes continue to spread, increasing the threat of mosquito-borne disease. Ongoing mosquito surveillance is necessary to track the introduction and establishment of these species in new areas and implement appropriate public health and vector control measures. Contributions from citizen science initiatives have been an important component in detecting, controlling, and raising awareness of invasive mosquitoes. The open-access biodiversity platform iNaturalist is an extensive source of human observations of wildlife, including arthropod vectors, and can be a useful supplementary tool for passive vector surveillance. In this study, the utility of iNaturalist data to support invasive mosquito surveillance was assessed by examining the distribution and seasonal data on four invasive Aedes species (IAS) in Europe and neighbouring countries. Almost 16,000 iNaturalist observations of mosquitoes were examined across 62 countries; 13% were identified as IAS, with a further 2% considered probable IAS. These included 16 observations of Aedes aegypti, 1582 Aedes albopictus, 373 Aedes japonicus, and 58 Aedes koreicus. iNaturalist observations of IAS were present in most known areas of establishment, but potential new regions of spread were also identified. These results further support the use of iNaturalist data as a low-cost source of arthropod data to assist existing vector surveillance.

  PublisherOA PDFDOI

• Tick Cell Culture Methods

  Methods in molecular biology · 2025-01-01

  articleSenior author
  PublisherDOI

• Development of a Recombinase-Mediated Cassette Exchange System for Gene Knockout and Expression of Non-Native Gene Sequences in Rickettsia

  Vaccines · 2025-01-22

  articleOpen access1st authorCorresponding

  Background/Objectives: Incidence of vector-borne diseases, including rickettsioses and anaplasmosis, has been increasing in many parts of the world. The obligate intracellular nature of rickettsial pathogens has hindered the development of robust genetic tools for the study of gene function and the identification of therapeutic targets. Transposon mutagenesis has contributed to recent progress in the identification of virulence factors in this important group of pathogens. Methods: Combining the efficiency of the himar1 transposon method with a recombinase-mediated system, we aimed to develop a genetic tool enabling the exchange of the transposon with a cassette encoding non-native sequences. Results: This approach was used in Rickettsia parkeri to insert a himar1 transposon encoding fluorescent protein and antibiotic resistance genes for visualization and selection, flanked by mismatched loxP sites to enable subsequent recombinase-mediated cassette exchange (RMCE). RMCE mediated by a plasmid-encoded Cre recombinase was then employed to replace the transposon with a different cassette containing alternate fluorescent and selection markers and epitopes of Anaplasma phagocytophilum antigens. The resulting genetically modified R. parkeri was trialed as a live-attenuated vaccine against spotted fever rickettsiosis and anaplasmosis in mice. Conclusions: The use of this system provides a well-established and relatively efficient way of inserting non-native sequences into the rickettsial genome, with applications for the study of gene function and vaccine development.

  PublisherOA PDFDOI

• An update on the ecology, seasonality and distribution of Culex modestus in England

  Journal of the European Mosquito Control Association · 2024-04-19 · 9 citations

  articleOpen access

  Abstract Culex ( Barraudius ) modestus is an important vector of West Nile virus (WNV) in Europe and it has the potential to play a bridge vector role in future WNV transmission in the UK. Here we provide an update on the known distribution of the species in England based on adult and larval data, characterise the preferred Cx. modestus larval habitats, and present adult and larval data from sites where the species is known to occur. Culex modestus is primarily found in the south-east of England, particularly in North Kent, the Thames Estuary, and along the Essex coast, and as far east as Orford Ness, Suffolk, and in Rainham Marshes, Essex, in the West. Adult numbers peak in mid-late July, with larval numbers highest in late August / early September. Preferred habitats in North Kent are warm, shallow, narrow ditches, with an abundance of marginal, submerged, and floating vegetation. Such environmental data on the distribution, seasonality and habitat preference of Cx. modestus are critical for informing WNV surveillance programmes, identifying at risk areas (associated with this species) and providing information for a targeted control strategy in the event of WNV transmission.

  PublisherOA PDFDOI

• iNaturalist community observations provide valuable data on human-mosquito encounters

  Journal of Vector Ecology · 2024-07-11 · 6 citations

  article1st authorCorresponding

  Mosquitoes (Diptera: Culicidae) and the pathogens they transmit represent a threat to human and animal health. Low-cost and effective surveillance methods are necessary to enable sustainable monitoring of mosquito distributions, diversity, and human interactions. This study examined the use of iNaturalist, an online, community-populated biodiversity recording database, for passive mosquito surveillance in the United Kingdom (UK) and Ireland, countries under threat from the introduction of invasive mosquitoes and emerging mosquito-borne diseases. The Mozzie Monitors UK & Ireland iNaturalist project was established to collate mosquito observations in these countries. Data were compared with existing long-term mosquito UK datasets to assess representativeness of seasonal and distribution trends in citizen scientist-recorded observations. The project collected 738 observations with the majority recorded 2020-2022. Records were primarily associated with urban areas, with the most common species Culex pipiens and Culiseta annulata significantly more likely to be observed in urban areas than other species. Analysis of images uploaded to the iNaturalist project also provided insights into human-biting behavior. Our analyses indicate that iNaturalist provides species composition, seasonal occurrence, and distribution figures consistent with existing datasets and is therefore a useful surveillance tool for recording information on human interactions with mosquitoes and monitoring species of concern.

  PublisherDOI

• Bacterial reprogramming of tick metabolism impacts vector fitness and susceptibility to infection

  Nature Microbiology · 2024-07-12 · 11 citations

  articleOpen access
  PublisherOA PDFDOI

• Mosquito diversity and abundance in English wetlands – empirical evidence to guide predictions for wetland suitability for mosquitoes (Diptera: Culicidae)

  Journal of the European Mosquito Control Association · 2024-06-11 · 7 citations

  articleOpen access

  Abstract The absence of habitat-based guidance for wetland managers on the British mosquito assemblages has in recent years prevented development of the ecological aspect of medical entomology in the UK. This has been particularly relevant in the context of emerging mosquito-borne disease and the creation of wetlands for biodiversity and flood-alleviation goals. This study aimed to provide empirically derived habitat-based predictions in order to assess the suitability of English wetland habitats for mosquitoes. Entomological field data on mosquito density and diversity were collected at 12 English wetlands in 2017 and 2018 using immature and adult mosquito surveys. Wetlands were chosen representing a number of wetland categories that included coastal, urban, wet woodland and established freshwater wetlands to identify key species and functional groups to inform predictions of mosquitoes by aquatic habitat type. Nineteen species were recorded from eight functional groups, totalling 38,577 adult female (19 mosquito species groups) and ~2,000 immature mosquitoes in 13 aquatic habitat types. Approximately 90% of all trapped mosquitoes were attributed to one of five species groups. The most common species were: Aedes ( Och. ) caspius (Pallas, 1771) (~35% of all mosquitoes), associated with coastal estuarine and flooded grassland sites, Ae. cantans/annulipes (19.7%) in wet woodland field sites, Anopheles claviger (16.2%) and Coquillettidia richiardii (12.6%) with the widest occurrence, found in nearly all field sites, and Ae. detritus (6.9%) in brackish field sites. Across the study, adult mosquito activity increased from week 21 with wet woodland Aedes mosquitoes, until week 40 with open-flood water species, with greatest diversity of species during weeks 23–30. The resulting data inform efforts towards developing predictive tools for non-entomologists to accurately predict the presence and abundance of British mosquitoes in a given habitat, using local knowledge of seasonal aquatic habitats.

  PublisherOA PDFDOI

• The role of autophagy in tick-endosymbiont interactions: insights from <i>Ixodes scapularis</i> and <i>Rickettsia buchneri</i>

  Microbiology Spectrum · 2023-12-01 · 2 citations

  articleOpen access

  ABSTRACT Approximately 80 identified tick species are recognized as vectors and impact global public health by transmitting a wide range of pathogens; however, little is known about the interactions of ticks with the microbiome that they harbor, let alone their bacterial symbionts. In this study, we used the black-legged tick, Ixodes scapularis Say (Acari: Ixodidae), a vector of seven human pathogens in the United States, and utilized Rickettsia buchneri sensu stricto ISO7 T (Rickettsiales: Rickettsiaceae), a spotted fever group (SFG) rickettsia that is an endosymbiont of I. scapularis, to investigate the role of autophagy in symbiont and tick interactions. We found that the expression profile of most autophagy family member proteins (ATGs) is down-regulated after R. buchneri infection in tick cell cultures. The autophagic process was observed by assessment of autophagosome formation and maturation in vitro (tick cell culture) and in vivo (tick ovary) in the presence of R. buchneri , whereas apoptosis was not induced. We further showed that R. buchneri infection triggered the accumulation of plasma membranes within cells. Suppressing autophagy via Atg8 siRNA interference inhibited intracellular rickettsial replication. This research indicates that autophagy regulation is important for the maintenance of R. buchneri in its I. scapularis tick host and provides more clues to solve the tick-symbiont interaction puzzle. IMPORTANCE Ticks are second only to mosquitoes in their importance as vectors of disease agents; however, tick-borne diseases (TBDs) account for the majority of all vector-borne disease cases in the United States (approximately 76.5%), according to Centers for Disease Control and Prevention reports. Newly discovered tick species and their associated disease-causing pathogens, and anthropogenic and demographic factors also contribute to the emergence and re-emergence of TBDs. Thus, incorporating different tick control approaches based on a thorough knowledge of tick biology has great potential to prevent and eliminate TBDs in the future. Here we demonstrate that replication of a transovarially transmitted rickettsial endosymbiont depends on the tick’s autophagy machinery but not on apoptosis. Our findings improve our understanding of the role of symbionts in tick biology and the potential to discover tick control approaches to prevent or manage TBDs.

  PublisherDOI

Frequent coauthors

• Jeremy C. Mottram

  49 shared

• Jolyon M. Medlock

  UK Health Security Agency

  46 shared

• Kayleigh M. Hansford

  29 shared

• Joseane Lima Prado Godinho

  University of Oklahoma

  20 shared

• Emma L. Gillingham

  UK Health Security Agency

  19 shared

• Graham H. Coombs

  University of South Australia

  16 shared

• Alexander G. C. Vaux

  UK Health Security Agency

  15 shared

• Roderick Williams

  University of the West of Scotland

  13 shared