A double whammy is challenging livestock farmers in sub-Saharan Africa,  ticks and tick-borne diseases, and tsetse-transmitted  African Animal Trypanosomosis (AAT) or Nagana. There is no vaccine against AAT, and existing drugs are losing their efficacy because of the emergence of drug-resistant parasites. Chemicals used against ticks, called acaricides, also face the problem of resistance.

Every year Nagana causes wasting and deaths in cattle resulting in economic losses that can be measured in billions of USD across sub-Saharan Africa. On the other hand, ticks suck blood from livestock, causing anaemia. Ticks also spread parasitic infections through their bites and lower animals’ value from the damage to the hides.

Parasites such as ticks and parasitic diseases like Nagana negatively affect the health and welfare of livestock, and they pose a heavy burden on communities that rely on livestock for their livelihood.

In Africa, parasites’ management and control are often reliant on chemicals and drugs, such as acaricides against ticks and trypanocides against tsetse-e.  However, resistance to many of the compounds currently in use is spreading, thus making parasite management and control increasingly challenging.

The Food and Agriculture Organization of the United Nations (FAO), in collaboration with the other Tripartite Organizations, the World Organisation for Animal Health (OIE) and the World Health Organization (WHO), have been active for years in the fight against the emergence and spread of antimicrobial resistance (AMR) in the livestock sector, aquaculture and crop production.

Expert consultation on the sustainable management of parasites

Presently, FAO is stepping up its activities against parasite resistance in livestock. In this framework, the FAO teams working on AMR and the Programme against African Trypanosomosis (PAAT) organized a virtual Expert Consultation on the sustainable management of parasites in livestock challenged by the global emergence of resistance.

The consultation was held on 9 - 10 November 2021, and it focused on acaricide resistance in ticks and trypanocidal drug resistance. Participants discussed the mechanisms of resistance, drivers, detection, surveillance, management and control. Experts from different institutions were involved, including international organizations, research and academic establishments, veterinary authorities from endemic countries, private sector and resource partners.

The issue of acaricide resistance in livestock ticks

The first day of the consultation focused on acaricide resistance of livestock ticks. Ten international speakers shared their experience regarding the global emergence of acaricide resistance in livestock ticks, which negatively affects the livelihoods of millions of small-scale producers.

Ticks develop resistance against different acaricides, aggravated by malpractices in their application, substandard products, and the lack of strategies to delay selection for resistance. A complicating factor is that there are no direct tests to differentiate between malpractice in chemical tick control and the development of resistance. The consultation advised FAO to develop guidelines for strategic tick control and management of acaricide resistance.

The challenge of trypanocidal drug resistance

The second day of the consultation focused on drug resistance in the treatment of African animal trypanosomosis. Experts warned that trypanocidal drug resistance has already been reported from over 15 countries in Africa, thus hampering disease control and negatively affecting food security and livelihoods.  Several factors contribute to the emergence and spread of trypanocidal drug resistance, such as drug overuse and misuse, circulation of substandard or fake products, and weak controls along the supply chains.

Experts recommended that the national authorities promote quality control of trypanocides, raise awareness on rational drug use, and strengthen data collection and surveillance to curb drug resistance.

FAO and the Tripartite should develop and disseminate guidelines and best practices, provide a platform for technical and scientific discussions and support advocacy, awareness, and resource mobilization at the international level. Academia should clarify the mechanisms and drivers of resistance, and develop more effective tools for management and control of the problem.