Ectoparasiticides and the challenge of Tick resistance

 Mandate of National Drug Authority

National Drug Authority controls the manufacture, importation, distribution and use of both human and veterinary drugs in the country. The three main concerns of veterinary drug regulation are quality, safety and efficacy (effectiveness). Veterinary drugs include acaricides which are the most important of animal drugs in terms of volumes and capital investment. Acaricides in Uganda are registered by NDA following well laid procedures that conform to international standards and following recommendation from Ministry of Agriculture, Animal industry and Fisheries (MAAIF), basing on pre-registration field trials on efficacy. These trials have always been coordinated by Ministry of Agriculture and carried out by the National Livestock Resources Research Institute (NaLIRRI). This ensures that NDA registers acaricides that are tested and confirmed effective in the Ugandan environment. In addition to the field trials NDA constantly monitors compliance to quality standards by random sampling and testing of acaricides on market using standard testing procedures at the NDA's National Drug Quality Control laboratory. National Drug Authority also has a system of collecting information and giving feedback on the performance of veterinary drugs on market and in use - the veterinary pharmacovigilance function.

  Acaricides on the Ugandan Market

As of September 2016, five groups of acaricides are registered and these include: Amidines (11 brands), synthetic pyrethroids (13 brands), Ivermectins / Macrolactic Lactones (30 brands), organophosphates (1 brand) and co-formulations of organophosphates and synthetic pyrethroids (2 brands) (see attached list).

These are imported by 15 licensed pharmacies and distributed to farmers across the country.

  Reports of acaricide ineffectiveness

Starting in 2012, increasing losses of cattle to tick-borne diseases have been noted. Although poor quality of acaricides has often been blamed, only one case has been substantiated involving counterfeited DecatixTM in 2013. National Drug Authority and its partners have been undertaking support missions, visiting farmers and institutions that are concerned with acaricide use. These missions reveal that farm practices in acaricide application have largely to contributed the problem: Mixing of different acaricides together, changing them very often, using very low to very high concentration of acaricides, with wrong applicators, and prolonged use of one type of acaricide; and ineffectiveness and that ticks have gained resistance to acaricides

  Evidence of tick resistance to acaricides

Super resistant ticks that are not responsive to all the molecules of acaricides on market have been identified on 68% of the farms that reported the problem in Western and Central Uganda in July 2016 and are believed to be spreading to other areas. This emergence of multiple acaricide resistant ticks and its implication on tick control in Uganda was also reported in January 2016 by Vudriko et al, 2016. No complaints have been registered from Northern and Eastern Uganda as yet, where tick samples collected showed susceptibility to all the molecules of acaricides on the market. This rules out quality issues as had been claimed earlier.

 Task force on ticks and tick borne diseases

The National Task Force on ticks and tick borne diseases was formed in 2012 and re-activated on 13/04/2016 when the tick challenge resurged. This task force is led by Ministry of Agriculture Animal Industry and Fisheries (MAAIF) - Director of Animal Resources with 4 other government institutions participating, purposely to steer forward the implementation of the short, medium and long term solutions to the problem. The task force has operated through regular meetings hosted at NDA (the secretariat of the task force), and responded to farmer problems through field visits and the evidence based tick control approach. To date, the task force has made the following recommendations which if implemented will go a long way to addressing the tick challenge in Uganda. The centers of implementation are as per the policy on delivery of veterinary services (2001) and National Veterinary Drug Policy (2002).

  Short term interventions (already going on)

  • Vaccination against East Coast Fever (ECF) : Popularization and encouraging of vaccination against ECF which is the most dangerous tick borne disease. The other tick borne diseases can be managed as they are cheap to treat.

  • The Evidence based prescription of acaricides. The evidence based model is where ticks are tested against all acaricides to see the effective ones to be used on a particular farm - piloted by Makerere College of Veterinary Medicine, funded by JICA.

  • Sensitization of the stakeholders especially in the affected areas (the cattle corridor).

  • Development and production of sensitization materials in terms of charts, brochures, visual aids, and manuals on acaricide use.

 Medium term interventions
  • Bridging the knowledge gaps: in-service training meetings with extension workers to reinforce knowledge on tick control and acaricide management; districts to ensure a more stable extension workforce at district level through which the knowledge gaps can be addressed.

  • Instituting more controls during importation of acaricides, requiring more mandatory testing of each batch of acaricides for quality.

  • Suspension of combination or multi-ingredient acaricides: These have been identified to limit the acaricide rotation system as they expose the ticks to more than one acaricide molecule at a time, indicating that more than one molecule can be resisted at the same time.  

  • Introduction of novel products to cleanse the affected herds and break the inter-farm variation of resistance.

All these will necessitate sourcing and pooling of resources to scale up the interventions so far made and transforming them into long term programs.

 Long term interventions.
  • Review of policies to provide for:

- Easier interventions by the Central Government in tick control,

- Central control and unification of extension messages regarding tick control among other livestock health issues (central command on animal health issues).

- A framework to institute control and enforcement of distribution of acaricides through an acaricide zoning system based on scientific evidence and continuous monitoring of resistance.

  • Strengthening of institutional framework by equipping the participating institutions (responsibility centers: MAAIF, NDA, Makerere College of Veterinary Medicine and NaLIRRI) to effectively control and manage acaricides.

  • Increased funding to sustain interventions proposed.

  •  Novel technologies for tick control.

  • Institution of subsidies for acaricides and acaricide application devices (pumps, dips and spray races) to ensure proper use of acaricides.


Addressing the challenge of acaricide resistant ticks requires involvement of all stakeholders including Local Governments.  It should be noted that the issue at hand is not failure in regulation, but rather acaricide resistance, a natural phenomenon caused by factors some of which are beyond the mandate of NDA. Regulatory capacity is built over time, and in a resource limited setting, duplication of roles is very counterproductive. It should also be noted that the 8th East African Community Sector Council on Agriculture and Food Security (EAC-SCAFS) recommended single agency strategy for regulation of both human and veterinary drugs in the EAC partner States, the same trend adopted by other regional blocks in Africa and beyond. National Drug Authority as a regulator spearheading the campaign against acaricide resistance will continue to be advised by MAAIF, guided by scientific evidence from research and field experiences from the farmers and field workers to ensure effective regulation of veterinary drugs.