How can ticks be reared for research? - briefly
Maintain a laboratory colony on pathogen‑free vertebrate hosts (e.g., rodents or rabbits) in incubators set to 22–25 °C and 80–95 % relative humidity, providing regular blood meals to adult females. Collect engorged females, allow oviposition, and store the eggs under identical conditions to generate successive generations for experimental work.
How can ticks be reared for research? - in detail
Ticks used in laboratory studies must be produced under controlled conditions that mimic their natural environment while allowing precise manipulation of variables. Successful colonisation begins with selecting a suitable species, typically Ixodes scapularis, Rhipicephalus microplus, or Dermacentor variabilis, depending on the research focus. Each species has specific temperature, humidity, and photoperiod requirements that must be reproduced in an incubator or climate‑controlled room.
The life cycle of hard ticks comprises egg, larva, nymph, and adult stages. Maintaining the colony involves the following steps:
- Egg incubation – Place freshly laid eggs on a moist substrate (e.g., plaster of Paris mixed with charcoal) at 22‑25 °C and 85‑95 % relative humidity. Monitor for hatching, which occurs within 2‑4 weeks depending on species.
- Larval feeding – Provide a small vertebrate host (usually a laboratory mouse or rabbit) with a restrained, anesthetised animal. Attach larvae to the host’s dorsal surface using a feeding capsule or mesh enclosure. Allow 3‑5 days of attachment before removal.
- Molting to nymphs – Transfer engorged larvae to a separate humid chamber identical to the egg incubator. Maintain the same temperature and humidity until molting, typically 1‑2 weeks.
- Nymphal feeding – Repeat the host‑attachment procedure with a slightly larger host (often a rabbit). Feeding duration is 4‑6 days. After engorgement, collect nymphs for molting.
- Adult feeding – Separate males and females. Place females on a larger host (e.g., a rabbit or sheep) for 5‑7 days; males may be kept on a separate cage with a small host for mating opportunities. Ensure females have access to males for successful fertilisation.
- Egg laying – After detachment, keep engorged females in a high‑humidity chamber to lay eggs. Collect egg masses weekly and store them in the same substrate used for incubation.
Key environmental parameters must be continuously recorded:
- Temperature: 22‑27 °C for most temperate species; tropical species may require 28‑30 °C.
- Relative humidity: 85‑95 % throughout all stages; sudden drops can cause desiccation and mortality.
- Photoperiod: 12 h light/12 h dark mimics natural cycles and regulates developmental timing.
Sanitation procedures prevent microbial contamination and cross‑species infection:
- Disinfect all containers, feeding capsules, and tools with 70 % ethanol before each use.
- Replace substrate after each molting cycle.
- Quarantine any tick batch that shows abnormal mortality or pathogen presence.
Colony management includes detailed record‑keeping:
- Log dates of oviposition, hatching, feeding, molting, and egg collection for each batch.
- Note host species, weight, and any anesthetic agents used.
- Track environmental readings hourly using data loggers.
Common problems and corrective actions:
- Low attachment rates – verify host skin temperature, ensure proper restraint, and check that capsules are not too tight.
- High mortality during molting – increase humidity, reduce airflow, and confirm substrate moisture.
- Fungal growth – lower humidity slightly, improve ventilation, and apply antifungal agents if necessary.
By strictly controlling environmental conditions, providing appropriate hosts, and maintaining rigorous hygiene and documentation, researchers can sustain healthy tick colonies for experiments involving pathogen transmission, vaccine testing, or ecological studies.