Drug resistance in African animal trypanosomes: A review

Abstract

Animal African trypanosmiasis (AAT) is the most important factor contributing to the sub potential performance of livestock. AAT is caused by Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei. Chemotherapy and chemoprophylaxis are the major means of combating the disease. An estimated 17 million cattle are treated with trypanocides annually. The emergence of drugresistant trypanosome strains is considered a serious problem in trypanosomiasis control particularly for the resource-poor, at-risk populations and farmers in Africa. Trypanocidal drug resistance is the decreased or absence of sensitivity of trypanosome strains to standard quality trypanocidal drugs at the dose recommended in a good veterinary practice. Different resistance mechanisms are acquired independently through exposure to different drugs. A good example for this is cross resistance for diminazene and isometamidium. Trypanosomiasis drug resistance has been officially reported in 21 African countries. Moreover, certain African countries reported the presence of multi drug resistance. Safeguarding the available trypanocidal drugs is mandatory to reduce the devastating impact of the disease.

Chemotherapeutic potentials of β‐ionone against Trypanosoma congolense infection: Inhibition of parasite proliferation, anemia development, trans‐sialidase (TconTS3 and TconTS4) gene expressions, and phospholipase A2

“…About 17 million cattle are treated with trypanocides annually but these chemotherapeutic drugs have been shown to be toxic and sometimes ineffective because of drug resistance by the parasites (Solomon & Workineh, 2018). Attempt to identify novel drug candidates to be used against Nagana has led us to identify β-ionone as a possible structural scaffold or potential candidate for mitigating disease progression and pathologies through downregulation of T. congolense trans-sialidase (TconTS3 and TconTS4) variants and inhibition of PLA 2 .…”

“…Due to the obvious threat Nagana poses, it is therefore imminent to find ways of tackling the disease (Samdi et al, 2010). As vaccination is almost impossible due to the phenomenon of antigenic variation, chemotherapy remains the only viable option for the control of Nagana but some of the available trypanocidal drugs are faced with problems of parasite resistance, toxicity, and the need for a parenteral means of administration (Solomon & Workineh, 2018). Therefore, satisfactory drugs are needed, especially those targeting the trans‐sialidases and PLA 2 since they are important factors contributing to the disease progression (Coustou et al, 2012).…”

Investigation on Prevalence of Canine Trypanosomiasis in the Conservation Areas of Bwindi-Mgahinga and Queen Elizabeth in Western Uganda

“…The lack of knowledge about CAT in southwestern Uganda may be due to the absence of concern of a possible role of dogs in trypanosomiasis transmission, yet routine livestock treatment is carried out with different trypanocides such as diminazene aceturate (Berenil®), isometamidium chloride (Samorin®), and homidium chloride (Novidium®) in many areas [ 37 , 38 ]. However, the recently recognized trypanosomes' resistance to isometamedium chloride and/or diminazene aceturate [ 39 – 41 ] remains a big threat to animal industry and calls for immediate satisfactory investigation. The present study offers knowledge about CAT prevalence and its possible role in transmission of trypanosomiasis among livestock, dogs, wildlife, and humans.…”

Investigation on Prevalence of Canine Trypanosomiasis in the Conservation Areas of Bwindi- Mgahinga and Queen Elizabeth in Western Uganda

“…The lack of knowledge about CAT in southwestern Uganda may be due to the absence of concern of a possible role of dogs in trypanosomiasis transmission, yet routine livestock treatment is carried out with different trypanocides such as diminazene aceturate (Berenil®), isometamidium chloride (Samorin®), and homidium chloride (Novidium®) in many areas [37,38]. However, the recently recognized trypanosomes' resistance to isometamedium chloride and/or diminazene aceturate [39][40][41] remains a big threat to animal industry and calls for immediate satisfactory investigation. The present study offers knowledge about CAT prevalence and its possible role in transmission of trypanosomiasis among livestock, dogs, wildlife, and humans.…”